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Sample records for ca ii ca

  1. Solar Ca II K Observations

    Science.gov (United States)

    Bertello, Luca; Pevtsov, Alexei A.; Tlatov, Andrey; Singh, Jagdev

    2016-07-01

    Some of the most important archives of past and current long-term solar synoptic observations in the resonance line of Ca II K are described here. These observations are very important for understanding the state of the solar magnetism on time scales up to several decades. The first observations of this kind began in 1904 at the Kodaikanal Observatory (India), followed by similar programs at different other locations. Regular full-disk Ca II K monitoring programs started in 1915 at the Mount Wilson Observatory (USA) and in 1917 at the National Solar Observatory of Japan. Beginning in 1919 and in 1926 regular observations were taken also at the Paris-Meudon Observatory (France) and at the "Donati solar tower telescope of the Arcetri Astrophysical Observatory in Italy, respectively. In 1926 the the Astronomical Observatory of the Coimbra University in Portugal started its own program of Ca II K observations. Although some of these programs have been terminated over the years, their data archives constitute a unique resource for studies of solar variability. In the early 1970s, the National Solar Observatory (NSO) at Sacramento Peak (USA) started a new program of daily Sun-as-a-star observations in the Ca II K line. Today the NSO is continuing these observations through its Synoptic Optical Long-term Investigations of the Sun (SOLIS) facility.

  2. Fast inversion of solar Ca II spectra

    CERN Document Server

    Beck, C; Rezaei, R; Louis, R E

    2014-01-01

    We present a fast (<< 1 s per profile) inversion code for solar Ca II lines. The code uses an archive of spectra that are synthesized prior to the inversion under the assumption of local thermodynamic equilibrium (LTE). We show that it can be successfully applied to spectrograph data or more sparsely sampled spectra from two-dimensional spectrometers. From a comparison to a non-LTE inversion of the same set of spectra, we derive a first-order non-LTE correction to the temperature stratifications derived in the LTE approach. The correction factor is close to unity up to log tau ~ -3 and increases to values of 2.5 and 4 at log tau = -6 in the quiet Sun and the umbra, respectively.

  3. Ca II Absorbers in the Sloan Digital Sky Survey: Statistics

    CERN Document Server

    Sardane, Gendith M; Rao, Sandhya M

    2014-01-01

    We present the results of a survey for CaII 3934,3969 absorption-line systems culled from ~ 95,000 Sloan Digital Sky Survey (SDSS) Data Release 7 and Data Release 9 quasar spectra. With 435 doublets identified in the catalog, this list is the largest CaII catalog compiled to date, spanning redshifts z = 0.3 A, is n_0=0.017 +/- 0.001. In comparison to MgII surveys, we found that only 3% of MgII systems in the SDSS have CaII, confirming that it is rare to identify CaII in quasar absorption-line surveys. We also report on some preliminary investigations of the nature of the two populations of CaII absorbers, and show that they can likely be distinguished using their MgII properties.

  4. CaII Κ Imaging to Understand UV Irradiance Variability

    Indian Academy of Sciences (India)

    R. Kariyappa

    2000-09-01

    To identify and understand the underlying physical mechanisms of total solar and UV irradiance variability and to estimate the contribution of various chromospheric features to UV irradiance, detailed analysis of spatially resolved data is required. The various chromospheric features have been segregated and different parameters have been derived from CaII Κ Spectroheliograms of NSO/Sac Peak and Kodaikanal Observatory and compared with UV irradiance flux measured in MgII h and k lines by NOAA 9 satellite. The important results of this detailed analysis of CaII Κ Images of 1992 together with UV irradiance data will be discussed in this paper.

  5. Correlation Between Sunspot Number and ca II K Emission Index

    CERN Document Server

    Bertello, Luca; Tlatov, Andrey; Singh, Jagdev

    2016-01-01

    Long-term synoptic observations in the resonance line of Ca II K constitute a fundamental database for a variety of retrospective analyses of the state of the solar magnetism. Synoptic Ca II K observations began in late 1904 at the Kodaikanal Observatory, in India. In early 1970s, the National Solar Observatory (NSO) at Sacramento Peak (USA) started a new program of daily Sun-as-a-star observations in the Ca II K line. Today the NSO is continuing these observations through its Synoptic Optical Long-term Investigations of the Sun (SOLIS) facility. These different data sets can be combined into a single disk-integrated Ca II K index time series that describes the average properties of the chromospheric emission over several solar cycles. We present such a Ca II K composite and discuss its correlation with the new entirely revised sunspot number data series. For this preliminary investigation, the scaling factor between pairs of time series was determined assuming a simple linear model for the relationship betwe...

  6. Correlation Between Sunspot Number and Ca ii K Emission Index

    Science.gov (United States)

    Bertello, Luca; Pevtsov, Alexei; Tlatov, Andrey; Singh, Jagdev

    2016-11-01

    Long-term synoptic observations in the resonance line of Ca ii K constitute a fundamental database for a variety of retrospective analyses of the state of the solar magnetism. Synoptic Ca ii K observations began in late 1904 at the Kodaikanal Observatory in India. In the early 1970s, the National Solar Observatory (NSO) at Sacramento Peak (USA) started a new program of daily Sun-as-a-star observations in the Ca ii K line. Today the NSO is continuing these observations through its Synoptic Optical Long-term Investigations of the Sun (SOLIS) facility. These different data sets can be combined into a single disk-integrated Ca ii K index time series that describes the average properties of the chromospheric emission over several solar cycles. We present such a Ca ii K composite and discuss its correlation with the new entirely revised sunspot number data series. For this preliminary investigation, the scaling factor between pairs of time series was determined assuming a simple linear model for the relationship between the monthly mean values during the duration of overlapping observations.

  7. The Infrared Ca II triplet as metallicity indicator

    CERN Document Server

    Carrera, Ricardo; Pancino, Elena; Zinn, Robert

    2007-01-01

    From observations of almost 500 RGB stars in 29 Galactic open and globular clusters, we have investigated the behaviour of the infrared Ca II triplet (8498, 8542 and 8662 \\AA) in the age range 13$\\leq$Age/Gyr$\\leq$0.25 and the metallicity range $-2.2\\leq$ [Fe/H] $\\leq$+0.47. These are the widest ranges of ages and metallicities in which the behaviour of the Ca II triplet lines has been investigated in a homogeneous way. We report the first empirical study of the variation of the CaII triplet lines strength, for given metallicities, with respect to luminosity. We find that the sequence defined by each cluster in the Luminosity-$\\Sigma$Ca plane is not exactly linear. However, when only stars in a small magnitude interval are observed, the sequences can be considered as linear. We have studied the the Ca II triplet lines on three metallicities scales. While a linear correlation between the reduced equivalent width ($W'_V$ or $W'_I$) versus metallicity is found in the \\citet{cg97} and \\citet{ki03} scales, a secon...

  8. The non-active stellar chromosphere: Ca II basal flux

    Science.gov (United States)

    Pérez Martínez, M. I.; Schröder, K.-P.; Hauschildt, P.

    2014-11-01

    We analyse high-resolution, high-s/n European Southern Observatories (ESO)-archive spectra (from UVES, the UV echelle spectrograph) of 76 inactive or modestly active stars of spectral type G to M, main sequence and giants. Using PHOENIX model photospheres with Ca II K lines that match the observed line profiles, we (i) revise the effective temperatures, (ii) obtain a precise surface flux scale for each star and (iii) directly determine the exact surface fluxes of each Ca II K chromospheric emission with respect to the photospheric line profile. We find that our stellar sample exhibits a lower boundary to its chromospheric surface flux distribution with an unprecedented definition. From a subsample of the 25 least active stars, we obtain a simple empirical formula for the basal Ca II flux as a function of effective temperature: log {F^basal_{Ca II(H+K)}} = 7.05(± 0.31) log {T_eff} - 20.86(± 1.15). This is in good agreement with the Mg II basal flux. In a direct comparison with the large body of Mt Wilson S-measurements of the chromospheric Ca II emission and its well-defined cut-off, excellent agreement is achieved as well. A new result, however, is the small scatter of the least active star's fluxes about the basal flux. It is about 25 per cent and equals the residual uncertainties of our approach. At the same time, we do not find any evidence for a gravity dependence within these limits. This strongly confirms the basal flux as a well-defined and universal phenomenon, which characterizes every inactive chromosphere.

  9. Spectropolarimetric capabilities of Ca II 8542 A line

    CERN Document Server

    Noda, C Quintero; Rodríguez, J de la Cruz; Katsukawa, Y; Ichimoto, K; Anan, T; Suematsu, Y

    2016-01-01

    The next generation of space and ground-based solar missions aim to study the magnetic properties of the solar chromosphere using the infrared Ca II lines and the He I 10830 {\\AA} line. The former seem to be the best candidates to study the stratification of magnetic fields in the solar chromosphere and their relation to the other thermodynamical properties underlying the chromospheric plasma. The purpose of this work is to provide a detailed analysis of the diagnostic capabilities of the Ca II 8542 {\\AA} line, anticipating forthcoming observational facilities. We study the sensitivity of the Ca II 8542 {\\AA} line to perturbations applied to the physical parameters of reference semi-empirical 1D model atmospheres using response functions and we make use of 3D MHD simulations to examine the expected polarization signals for moderate magnetic field strengths. Our results indicate that the Ca II 8542 {\\AA} line is mostly sensitive to the layers enclosed between $\\log$ $\\tau=[0,-5.5]$, under the physical conditio...

  10. Flavonoid Myricetin Modulates GABAA Receptor Activity through Activation of Ca2+ Channels and CaMK-II Pathway

    Directory of Open Access Journals (Sweden)

    Xiao Hu Zhang

    2012-01-01

    Full Text Available The flavonoid myricetin is found in several sedative herbs, for example, the St. John's Wort, but its influence on sedation and its possible mechanism of action are unknown. Using patch-clamp technique on a brain slice preparation, the present study found that myricetin promoted GABAergic activity in the neurons of hypothalamic paraventricular nucleus (PVN by increasing the decay time and frequency of the inhibitory currents mediated by GABAA receptor. This effect of myricetin was not blocked by the GABAA receptor benzodiazepine- (BZ- binding site antagonist flumazenil, but by KN-62, a specific inhibitor of the Ca2+/calmodulin-stimulated protein kinase II (CaMK-II. Patch clamp and live Ca2+ imaging studies found that myricetin could increase Ca2+ current and intracellular Ca2+ concentration, respectively, via T- and L-type Ca2+ channels in rat PVN neurons and hypothalamic primary culture neurons. Immunofluorescence staining showed increased phosphorylation of CaMK-II after myricetin incubation in primary culture of rat hypothalamic neurons, and the myricetin-induced CaMK-II phosphorylation was further confirmed by Western blotting in PC-12 cells. The present results suggest that myricetin enhances GABAA receptor activity via calcium channel/CaMK-II dependent mechanism, which is distinctively different from that of most existing BZ-binding site agonists of GABAA receptor.

  11. Radiative emission of solar features in Ca II K

    CERN Document Server

    Criscuoli, S; Fontenla, J; Giorgi, F; Rast, M; Solanki, S; Uitenbroek, H

    2010-01-01

    We investigated the radiative emission of different types of solar features in the spectral range of the Ca II K line. We analyzed full-disk 2k x 2k observations from the PSPT Precision Solar Photometric Telescope. The data were obtained by using three narrow-band interference filters that sample the Ca II K line with different pass bands. Two filters are centered in the line core, the other in the red wing of the line. We measured the intensity and contrast of various solar features, specifically quiet Sun (inter-network), network, enhanced network, plage, and bright plage (facula) regions. Moreover, we compared the results obtained with those derived from the numerical synthesis performed for the three PSPT filters with a widely used radiative code on a set of reference semi-empirical atmosphere models.

  12. The Ca II triplet in red giant spectra: [Fe/H] determinations and the role of [Ca/Fe

    CERN Document Server

    Da Costa, G S

    2015-01-01

    Measurements are presented and analyzed of the strength of the Ca II triplet lines in red giants in Galactic globular and open clusters, and in a sample of red giants in the LMC disk that have significantly different [Ca/Fe] abundance ratios to the Galactic objects. The Galactic objects are used to generate a calibration between Ca II triplet line strength and [Fe/H], which is then used to estimate [Fe/H]_CaT for the LMC stars. The values are then compared with the [Fe/H]_spec determinations from high dispersion spectroscopy. After allowance for a small systematic offset the two abundance determinations are in excellent agreement. Further, as found in earlier studies, e.g., Battaglia et al. (2008), the difference is only a very weak function of the [Ca/Fe] ratio. For example, changing [Ca/Fe] from +0.3 to -0.2 causes the Ca II based abundance to underestimate [Fe/H]_spec by only ~0.15 dex, assuming a Galactic calibration. Consequently, the Ca II triplet approach to metallicity determinations can be used witho...

  13. Study on Effect of Gd (III) Speciation on Ca (II) Speciation in Human Blood Plasma by Computer Simulation

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Ca (II) speciation and effect of Gd (III) speciation on Ca (II) speciation in human blood plasma were studied by computer simulation. [CaHCO3]+ is a predominant compound species of Ca (II). Gd (III) can compete with Ca (II) for biological molecules. The presence of Gd (III) results in a increase of concentration of free Ca (II) and a decrease of concentration of Ca (II) compounds.

  14. Probing low-redshift galaxies using quasar absorption lines with an emphasis on Ca II absorption

    Science.gov (United States)

    Sardane, Gendith M.

    2016-05-01

    We searched for intervening CaII absorption in nearly 95,000 quasar spectra with i≤20 from the Sloan Digital Sky Survey(SDSS) data releases DR7+DR9. Our identification of >400 CaII systems is the largest compilation of CaII absorbers in a blind search. (Abstract shortened by ProQuest.).

  15. Morphological Properties of Slender Ca ii H Fibrils Observed by Sunrise II

    Science.gov (United States)

    Gafeira, R.; Lagg, A.; Solanki, S. K.; Jafarzadeh, S.; van Noort, M.; Barthol, P.; Blanco Rodríguez, J.; del Toro Iniesta, J. C.; Gandorfer, A.; Gizon, L.; Hirzberger, J.; Knölker, M.; Orozco Suárez, D.; Riethmüller, T. L.; Schmidt, W.

    2017-03-01

    We use seeing-free high spatial resolution Ca ii H data obtained by the Sunrise observatory to determine properties of slender fibrils in the lower solar chromosphere. In this work we use intensity images taken with the SuFI instrument in the Ca ii H line during the second scientific flight of the Sunrise observatory to identify and track elongated bright structures. After identification, we analyze theses structures to extract their morphological properties. We identify 598 slender Ca ii H fibrils (SCFs) with an average width of around 180 km, length between 500 and 4000 km, average lifetime of ≈400 s, and average curvature of 0.002 arcsec‑1. The maximum lifetime of the SCFs within our time series of 57 minutes is ≈2000 s. We discuss similarities and differences of the SCFs with other small-scale, chromospheric structures such as spicules of type I and II, or Ca ii K fibrils.

  16. Morphological properties of slender Ca II H fibrils observed by SUNRISE II

    CERN Document Server

    Gafeira, R; Solanki, Sami K; Jafarzadeh, Shahin; Van Noort, M; Barthol, P; Rodriguez, J Blanco; Iniesta, J C del Toro; Gandorfer, A; Gizon, L; Hirzberger, J; Knolker, M; Suarez, D Orozco; Riethmüller, T L; Schmidt, W

    2016-01-01

    We use seeing-free high spatial resolution Ca II H data obtained by the SUNRISE observatory to determine properties of slender fibrils in the lower solar chromosphere. In this work we use intensity images taken with the SUFI instrument in the Ca II H line during the second scientific flight of the SUNRISE observatory to identify and track elongated bright structures. After the identification, we analyze theses structures in order to extract their morphological properties. We identify 598 slender Ca II H fibrils (SCFs) with an average width of around 180 km, a length between 500 km and 4000 km, an average lifetime of ~400 s, and an average curvature of 0.002 arcsec^-1. The maximum lifetime of the SCFs within our time series of 57 minutes is ~2000 s. We discuss similarities and differences of the SCFs with other small-scale, chromospheric structures such as spicules of type I and II, or Ca II K fibrils.

  17. Macrocyclic receptor showing extremely high Sr(II)/Ca(II) and Pb(II)/Ca(II) selectivities with potential application in chelation treatment of metal intoxication.

    Science.gov (United States)

    Ferreirós-Martínez, Raquel; Esteban-Gómez, David; Tóth, Éva; de Blas, Andrés; Platas-Iglesias, Carlos; Rodríguez-Blas, Teresa

    2011-04-18

    Herein we report a detailed investigation of the complexation properties of the macrocyclic decadentate receptor N,N'-Bis[(6-carboxy-2-pyridil)methyl]-4,13-diaza-18-crown-6 (H(2)bp18c6) toward different divalent metal ions [Zn(II), Cd(II), Pb(II), Sr(II), and Ca(II)] in aqueous solution. We have found that this ligand is especially suited for the complexation of large metal ions such as Sr(II) and Pb(II), which results in very high Pb(II)/Ca(II) and Pb(II)/Zn(II) selectivities (in fact, higher than those found for ligands widely used for the treatment of lead poisoning such as ethylenediaminetetraacetic acid (edta)), as well as in the highest Sr(II)/Ca(II) selectivity reported so far. These results have been rationalized on the basis of the structure of the complexes. X-ray crystal diffraction, (1)H and (13)C NMR spectroscopy, as well as theoretical calculations at the density functional theory (B3LYP) level have been performed. Our results indicate that for large metal ions such as Pb(II) and Sr(II) the most stable conformation is Δ(δλδ)(δλδ), while for Ca(II) our calculations predict the Δ(λδλ)(λδλ) form being the most stable one. The selectivity that bp18c6(2-) shows for Sr(II) over Ca(II) can be attributed to a better fit between the large Sr(II) ions and the relatively large crown fragment of the ligand. The X-ray crystal structure of the Pb(II) complex shows that the Δ(δλδ)(δλδ) conformation observed in solution is also maintained in the solid state. The Pb(II) ion is endocyclically coordinated, being directly bound to the 10 donor atoms of the ligand. The bond distances to the donor atoms of the pendant arms (2.55-2.60 Å) are substantially shorter than those between the metal ion and the donor atoms of the crown moiety (2.92-3.04 Å). This is a typical situation observed for the so-called hemidirected compounds, in which the Pb(II) lone pair is stereochemically active. The X-ray structures of the Zn(II) and Cd(II) complexes show that

  18. Study of the Sextans dwarf spheroidal galaxy from the DART CaII triplet survey

    NARCIS (Netherlands)

    Battaglia, G.; Tolstoy, E.; Helmi, A.; Irwin, M.; Parisi, P.; Hill, V.; Jablonka, P.

    2011-01-01

    We use Very Large Telescope (VLT)/Fibre Large Array Multi Element Spectrograph (FLAMES) intermediate-resolution (R similar to 6500) spectra of individual red giant branch stars in the near-infrared Ca ii triplet (CaT) region to investigate the wide-area metallicity properties and internal kinematics

  19. K-band Imaging of strong CaII-absorber host galaxies at z~1

    CERN Document Server

    Hewett, Paul

    2007-01-01

    We present K-band imaging of fields around 30 strong CaII absorption line systems, at 0.7CaII absorption of the form (L/L*)^0.7 reproduces the observations well. The luminosity-dependent cross-section for the CaII absorbers appears to be significantly stronger than the established (L/L*)^0.4 dependence for MgII absorbers. The associated galaxies lie at large physical distances from the CaII-absorbing gas; we find a mean impact parameter of 24kpc (H0=70km\\s\\Mpc). Combined with the observed number density of CaII absorbers the large physical separations result in an inferred filling factor of only ~10 per cent. The physical origin of the strong CaII absorption remains unclear,...

  20. Measurements of Ca II Infrared Triplet Lines of Young Stellar Objects

    CERN Document Server

    Moto'oka, Keiko

    2015-01-01

    Equivalent widths and line widths of Ca II infrared triplet emission lines were measured in high-resolution optical spectra of 39 young stellar objects.We found that the equivalent widths of the emission lines decrease with stellar evolution. It has been often claimed that strong chromospheric activity is generated by a dynamo process caused by fast rotation of the photosphere. However, we found no clear correlation between the strength of the Ca II lines and the stellar rotation velocity. Instead, we found that the objects with high mass accretion rates had stronger Ca II emission lines. This correlation supports the turbulent chromosphere model or the magnetic accretion theory for classical T Tauri stars. We also noticed that the equivalent widths of Ca II lines of transitional disk objects are one-tenth of those of classical T Tauri stars, even if the masses of the circumstellar disks are comparable.

  1. The location of the Ca II ions in the beta Pictoris disk

    Science.gov (United States)

    Hobbs, L. M.; Welty, D. E.; Lagrange-Henri, A. M.; Ferlet, R.; Vidal-Madjar, A.

    1988-01-01

    Echelle spectra of beta Pictoris have been obtained in the region of the Ca II 8542A line which arises from the metastable 3d 2D5/2 level. A narrow, weak, circumstellar absorption line is seen at the stellar radial velocity. A simple theory is developed of the radiative pumping of the metastable levels of the Ca II ions by the radiation from the star at the H and K lines. The relatively large fractional population, N3(Ca II)/N1(Ca II) of roughly 0.05, observed for the metastable level then requires that the calcium absorbers be largely concentrated within about 1 AU of the star. This result confirms two previous, independent estimates of the location of this gas. A time-variable circumstellar component of the 8542A line also is found at an infall velocity of about 15 km/s.

  2. A dynamic model of interactions of Ca2+, calmodulin, and catalytic subunits of Ca2+/calmodulin-dependent protein kinase II.

    Directory of Open Access Journals (Sweden)

    Shirley Pepke

    2010-02-01

    Full Text Available During the acquisition of memories, influx of Ca2+ into the postsynaptic spine through the pores of activated N-methyl-D-aspartate-type glutamate receptors triggers processes that change the strength of excitatory synapses. The pattern of Ca2+influx during the first few seconds of activity is interpreted within the Ca2+-dependent signaling network such that synaptic strength is eventually either potentiated or depressed. Many of the critical signaling enzymes that control synaptic plasticity,including Ca2+/calmodulin-dependent protein kinase II (CaMKII, are regulated by calmodulin, a small protein that can bindup to 4 Ca2+ ions. As a first step toward clarifying how the Ca2+-signaling network decides between potentiation or depression, we have created a kinetic model of the interactions of Ca2+, calmodulin, and CaMKII that represents our best understanding of the dynamics of these interactions under conditions that resemble those in a postsynaptic spine. We constrained parameters of the model from data in the literature, or from our own measurements, and then predicted time courses of activation and autophosphorylation of CaMKII under a variety of conditions. Simulations showed that species of calmodulin with fewer than four bound Ca2+ play a significant role in activation of CaMKII in the physiological regime,supporting the notion that processing of Ca2+ signals in a spine involves competition among target enzymes for binding to unsaturated species of CaM in an environment in which the concentration of Ca2+ is fluctuating rapidly. Indeed, we showed that dependence of activation on the frequency of Ca2+ transients arises from the kinetics of interaction of fluctuating Ca2+with calmodulin/CaMKII complexes. We used parameter sensitivity analysis to identify which parameters will be most beneficial to measure more carefully to improve the accuracy of predictions. This model provides a quantitative base from which to build more complex dynamic

  3. Metal Abundance Calibration of the Ca II Triplet Lines in RR Lyrae Stars

    CERN Document Server

    Wallerstein, George; Huang, Wenjin

    2011-01-01

    The GAIA satellite is likely to observe thousands of RR Lyrae stars within a small spectral window, between 8470A and 8750A, at a resolution of 11,500. In order to derive the metallicity of RR Lyrae stars from Gaia, we have obtained numerous spectra of RR Lyrae stars at a resolution of 35,000 with the Apache Point Observatory 3.5 m echelle spectrograph. We have correlated the Ca II triplet line strengths with metallicity as derived from Fe II abundances, analogous to Preston's (1959) use of the Ca II K line to estimate the metallicity of RR Lyrae stars. The Ca II line at 8498A is the least blended with neighboring Paschen lines and thus provides the best correlation.

  4. Fusion-activated Ca(2+ entry: an "active zone" of elevated Ca(2+ during the postfusion stage of lamellar body exocytosis in rat type II pneumocytes.

    Directory of Open Access Journals (Sweden)

    Pika Miklavc

    Full Text Available Ca(2+ is essential for vesicle fusion with the plasma membrane in virtually all types of regulated exocytoses. However, in contrast to the well-known effects of a high cytoplasmic Ca(2+ concentration ([Ca(2+](c in the prefusion phase, the occurrence and significance of Ca(2+ signals in the postfusion phase have not been described before.We studied isolated rat alveolar type II cells using previously developed imaging techniques. These cells release pulmonary surfactant, a complex of lipids and proteins, from secretory vesicles (lamellar bodies in an exceptionally slow, Ca(2+- and actin-dependent process. Measurements of fusion pore formation by darkfield scattered light intensity decrease or FM 1-43 fluorescence intensity increase were combined with analysis of [Ca(2+](c by ratiometric Fura-2 or Fluo-4 fluorescence measurements. We found that the majority of single lamellar body fusion events were followed by a transient (t(1/2 of decay = 3.2 s rise of localized [Ca(2+](c originating at the site of lamellar body fusion. [Ca(2+](c increase followed with a delay of approximately 0.2-0.5 s (method-dependent and in the majority of cases this signal propagated throughout the cell (at approximately 10 microm/s. Removal of Ca(2+ from, or addition of Ni(2+ to the extracellular solution, strongly inhibited these [Ca(2+](c transients, whereas Ca(2+ store depletion with thapsigargin had no effect. Actin-GFP fluorescence around fused LBs increased several seconds after the rise of [Ca(2+](c. Both effects were reduced by the non-specific Ca(2+ channel blocker SKF96365.Fusion-activated Ca(2+entry (FACE is a new mechanism that leads to [Ca(2+](c transients at the site of vesicle fusion. Substantial evidence from this and previous studies indicates that fusion-activated Ca(2+ entry enhances localized surfactant release from type II cells, but it may also play a role for compensatory endocytosis and other cellular functions.

  5. 3D Temperature Mapping of Solar Photospheric Fine Structure Using Ca II H Filtergrams

    CERN Document Server

    Henriques, V M J

    2012-01-01

    Context. The wings of the Ca II H and K lines provide excellent photospheric temperature diagnostics. At the Swedish 1-meter Solar Telescope the blue wing of Ca II H is scanned with a narrowband interference filter mounted on a rotation stage. This provides up to 0"10 spatial resolution filtergrams at high cadence that are concurrent with other diagnostics at longer wavelengths. Aims. The aim is to develop observational techniques that provide the photospheric temperature stratification at the highest spatial resolution possible and use those to compare simulations and observations at different heights. Methods. We use filtergrams in the Ca II H blue wing obtained with a tiltable interference filter at the SST. Synthetic observations are produced from 3D HD and 3D MHD numerical simulations and degraded to match the observations. The temperature structure obtained from applying the method to the synthetic data is compared with the known structure in the simulated atmospheres and with observations of an active ...

  6. The Strings of Eta Carina: The HST/STIS Spectra and [Ca II

    Science.gov (United States)

    Melendez, M. B.; Gull, T. R.; Bautista, M. A.; Badnell, N. R.

    2006-01-01

    Long linear, filamentary ejecta, are found to move at very high velocity external to the Homunculus, the circumstellar hourglass-shaped ejecta surrounding Eta Carinae. The origin of the strings is a puzzle. As an example, the Weigelt Blobs have N at 10X solar and C, O at 0.01X solar abundance, along with He/H significantly enhanced. This abundance pattern is evidence for extreme CNO-processing. Similarly, the Strontium Filament has Ti/Ni at 100X solar, presumably due to the lack of oxygen to form Ti-oxide precipitates onto dust grains. We have obtained 2-D spectra with the HST/STIS of the Strontium Filament and a portion of a string. These deep spectral exposures, at moderate dispersion, span much of the near red spectral region from 5000 to 9000A. We have identified twelve emission lines in these spectra with proper velocities and spatial structure of this string and obtained line ratios for [Ca II] (7293/7325A) and [Fe Ill (7157/8619A) which are useful for determining physical conditions in this nebulosity. In an attempt to use the [Ca II] ratio to determine the physical parameters, and ultimately the abundances in the strings, we have constructed a statistical equilibrium model for Ca II , including radiative and collisional rates. These results incorporate our newly calculated atomic data for levels n = 3,4,5 and 6 configurations of Ca II. The aim is to compute the [Ca II] line ratios and use them as a diagnostic of the physical parameters. Using the [Fe II] ratio we find that for Te=10,000 K, the electron density is Ne approx.10(exp 6)/cu cm. We plan to use the [Ca II] ratio to confirm this result. Then, we will extend the use of this multilevel model Ca II atom to study the physical conditions of the Strontium filament where eight lines of Ca II, both allowed and forbidden, had been identified. With the physical conditions determined, we will be able to derive reliable estimates for the gas phase abundances in the strings.

  7. CaMK-II activation is essential for zebrafish inner ear development and acts through Delta-Notch signaling.

    Science.gov (United States)

    Rothschild, Sarah C; Lahvic, Jamie; Francescatto, Ludmila; McLeod, Jamie J A; Burgess, Shawn M; Tombes, Robert M

    2013-09-01

    Zebrafish inner ear development is characterized by the crystallization of otoliths onto immotile kinocilia that protrude from sensory "hair" cells. The stereotypical formation of these sensory structures is dependent on the expression of key patterning genes and on Ca2+ signals. One potential target of Ca2+ signaling in the inner ear is the type II Ca2+/calmodulin-dependent protein kinase (CaMK-II), which is preferentially activated in hair cells, with intense activation at the base of kinocilia. In zebrafish, CaMK-II is encoded by seven genes; the expression of one of these genes (camk2g1) is enriched in hair cells. The suppression of camk2g1 expression by antisense morpholino oligonucleotides or inhibition of CaMK-II activation by the pharmacological antagonist, KN-93, results in aberrant otolith formation without preventing cilia formation. In fact, CaMK-II suppression results in additional ciliated hair cells and altered levels of Delta-Notch signaling members. DeltaA and deltaD transcripts are increased and DeltaD protein accumulates in hair cells of CaMK-II morphants, indicative of defective recycling and/or exocytosis. Our findings indicate that CaMK-II plays a critical role in the developing ear, influencing cell differentiation through extranuclear effects on Delta-Notch signaling. Continued expression and activation of CaMK-II in maculae and cristae in older embryos suggests continued roles in auditory sensory maturation and transduction.

  8. VizieR Online Data Catalog: CaII-Mv Correlation (Wilson-Bappu Effect) (Wallerstein+

    Science.gov (United States)

    Wallerstein, G.; Machado-Pelaez, L.; Gonzalez, G.

    1999-07-01

    Hipparcos parallaxes were used to derive absolute visual magnitudes of G, K, and M stars with Ca II emission line widths previously measured by O.C. Wilson. A linear relationship similar to the one derived originally by Wilson & Bappu and improved by Lutz & Kelker was found from Mv=+7 to -2. For stars brighter than Mv=-2 a substantial number of stars show Ca II emission lines that are broader than expected from the linear fit. Most of those stars are bright giants and supergiants of type G. (3 data files).

  9. Bcl10 is phosphorylated on Ser138 by Ca2+/calmodulin-dependent protein kinase II.

    Science.gov (United States)

    Ishiguro, Kazuhiro; Ando, Takafumi; Goto, Hidemi; Xavier, Ramnik

    2007-03-01

    Ordered assembly of scaffold proteins Carma1-Bcl10-Malt1 determines NF-kappaB activation following T cell receptor (TCR) engagement. Carma1-Bcl10 interaction and the signaling pathway are controlled by Carma1 phosphorylation, which are induced by PKCtheta and Ca(2+)/calmodulin-dependent protein kinase II (CaMKII). In addition to Carma1 phosphorylation, previous studies have demonstrated that Bcl10 is phosphorylated in the C-terminal Ser/Thr rich region following TCR engagement. However the kinases that phosphorylate Bcl10 are incompletely understood. Here we show that CaMKII phosphorylates Bcl10 on Ser138. Furthermore, a CaMKII inhibitor, KN93, and CaMKII siRNA substantially reduce Bcl10 phosphorylation induced by phorbol myristate acetate/ionomycin. S138A mutation prolongs Bcl10-induced NF-kappaB activation, suggesting that Bcl10 phosphorylation is involved in attenuation of NF-kappaB activation. These findings suggest that CaMKII modulates NF-kappaB activation via phosphorylating Bcl10 as well as Carma1.

  10. Theoretical study on the role of Ca(2+) at the S2 state in photosystem II.

    Science.gov (United States)

    Yang, Jingxiu; Hatakeyama, Makoto; Ogata, Koji; Nakamura, Shinichiro; Li, Can

    2014-12-11

    In photosynthesis, calcium is crucial for oxygen evolution. In the absence of Ca(2+), the Kok cycle has been proven to stop at S2 with Yz•. To explore the reason, photosystem II (PSII) S2 models (in total 32452 atoms) with different metal ions (Ca(2+), Sr(2+), and K(+)) or without Ca(2+) involved in the oxygen evolution complex (OEC) have been theoretically studied based on the previous dynamic study of PSII. It is found that the portion of the Mn1 d-orbital decreases in the highest occupied molecular orbitals for Ca(2+)-depleted PSII. This feature is unfavorable for the electron transfer from the OEC to the Yz•. Furthermore, the proton donor-acceptor distance was found elongated by the alternation of the binding water in the absence of Ca(2+). The isolated vibrational modes of the key water molecules along the path and their high frequency of the OH stretching modes also suggested the difficulty of the proton transfer from the OEC toward the proton exit channel. This work provides one mechanistic explanation for the inactivity of Ca(2+)-depleted PSII.

  11. Observations of Chromospheric Anemone Jets with Hinode SOT and Hida Ca II Spectroheliogram

    CERN Document Server

    Morita, Satoshi; Ueno, Satoru; Ichimoto, Kiyoshi; Kitai, Reizaburo; Otsuji, Ken-ichi

    2010-01-01

    We present the first simultaneous observations of chromospheric "anemone" jets in solar active regions with Hinode SOT Ca II H broadband filetergram and Ca II K spetroheliogram on the Domeless Solar Telescope (DST) at Hida Observatory. During the coordinated observation, 9 chromospheric anemone jets were simultaneously observed with the two instruments. These observations revealed three important features, i.e.: (1) the jets are generated in the lower chromosphere, (2) the length and lifetime of the jets are 0.4-5 Mm and 40-320 sec, (3) the apparent velocity of the jets with Hinode SOT are 3-24 km/s, while Ca II K3 component at the jets show blueshifts (in 5 events) in the range of 2- 6 km/s. The chromospheric anemone jets are associated with mixed polarity regions which are either small emerging flux regions or moving magnetic features. It is found that the Ca II K line often show red or blue asymmetry in K2/K1 component: the footpoint of the jets associated with emerging flux regions often show redshift (2-...

  12. Structure and Dynamics of Isolated Internetwork Ca II H Bright Points Observed by Sunrise

    CERN Document Server

    Jafarzadeh, S; Feller, A; Lagg, A; Pietarila, A; Danilovic, S; Riethmüller, T L; Pillet, V Martínez

    2012-01-01

    We aim to improve our picture of the low chromosphere in the quiet-Sun internetwork by investigating the intensity, horizontal velocity, size and lifetime variations of small bright points (BPs; diameter smaller than 0.3 arcsec) observed in the Ca II H 3968 {\\AA} passband along with their magnetic field parameters, derived from photospheric magnetograms. Several high-quality time series of disc-centre, quiet-Sun observations from the Sunrise balloon-borne solar telescope, with spatial resolution of around 100 km on the solar surface, have been analysed to study the dynamics of BPs observed in the Ca II H passband and their dependence on the photospheric vector magnetogram signal. Parameters such as horizontal velocity, diameter, intensity and lifetime histograms of the isolated internetwork and magnetic Ca II H BPs were determined. Mean values were found to be 2.2 km/s, 0.2 arcsec (150 km), 1.48 average Ca II H quiet-Sun and 673 sec, respectively. Interestingly, the brightness and the horizontal velocity of B...

  13. CaII Absorbers in the Sloan Digital Sky Survey: Element Abundances and Dust

    CERN Document Server

    Sardane, Gendith M; Rao, Sandhya M

    2015-01-01

    We present measurements of element abundance ratios and dust in CaII~absorbers identified in SDSS DR7+DR9. In an earlier paper we formed a statistical sample of 435 CaII absorbers and postulated that their statistical properties might be representative of at least two populations of absorbers. Here we show that if the absorbers are roughly divided into two subsamples with CaII rest equivalent widths larger and smaller than $W_0^{\\lambda 3934} = 0.7$ \\AA, they are then representative of two physically different populations. Comparisons of abundance ratios between the two CaII absorber populations indicate that the weaker $W_0^{\\lambda 3934}$ absorbers have properties consistent with halo-type gas, while the stronger absorbers have properties intermediate between halo- and disk-type gas. We also show that, on average, the dust extinction properties of the overall sample is consistent with a LMC or SMC dust law, and the stronger absorbers are nearly 6 times more reddened than their weaker counterparts. The absor...

  14. Regulation of voltage-gated Ca(2+) currents by Ca(2+)/calmodulin-dependent protein kinase II in resting sensory neurons.

    Science.gov (United States)

    Kostic, Sandra; Pan, Bin; Guo, Yuan; Yu, Hongwei; Sapunar, Damir; Kwok, Wai-Meng; Hudmon, Andy; Wu, Hsiang-En; Hogan, Quinn H

    2014-09-01

    Calcium/calmodulin-dependent protein kinase II (CaMKII) is recognized as a key element in encoding depolarization activity of excitable cells into facilitated voltage-gated Ca(2+) channel (VGCC) function. Less is known about the participation of CaMKII in regulating VGCCs in resting cells. We examined constitutive CaMKII control of Ca(2+) currents in peripheral sensory neurons acutely isolated from dorsal root ganglia (DRGs) of adult rats. The small molecule CaMKII inhibitor KN-93 (1.0μM) reduced depolarization-induced ICa by 16-30% in excess of the effects produced by the inactive homolog KN-92. The specificity of CaMKII inhibition on VGCC function was shown by the efficacy of the selective CaMKII blocking peptide autocamtide-2-related inhibitory peptide in a membrane-permeable myristoylated form, which also reduced VGCC current in resting neurons. Loss of VGCC currents is primarily due to reduced N-type current, as application of mAIP selectively reduced N-type current by approximately 30%, and prior N-type current inhibition eliminated the effect of mAIP on VGCCs, while prior block of L-type channels did not reduce the effect of mAIP on total ICa. T-type currents were not affected by mAIP in resting DRG neurons. Transduction of sensory neurons in vivo by DRG injection of an adeno-associated virus expressing AIP also resulted in a loss of N-type currents. Together, these findings reveal a novel molecular adaptation whereby sensory neurons retain CaMKII support of VGCCs despite remaining quiescent.

  15. Adsorption and desorption of Zn(II) and Cu(II) on Ca- alginate immobilized activated rice bran

    Science.gov (United States)

    Suratman, A.; Kamalia, N. Z.; Kusumawati, W. A.

    2016-02-01

    Ca-alginate immobilized activated rice bran has been used for adsorption of Zn(II) and Cu(II) from aqueous solution. The effect of the pH, kinetics model, adsorption isotherm and desorption on the adsorption performance was investigated. Activated rice bran was immobilized by the entrapment in alginate beads. The adsorption strength of Ca-alginate immobilized activated rice bran was compared to Ca-alginate and non-immobilized activated rice bran. The concentrations of adsorbed ions were analyzed using Atomic Absorption Spectrophotometer (AAS). The result showed that pH of 4.0 and the contact time of 120 min are the optimum condition for adsorption of Zn(II) and Cu(II). The adsorption kinetic of Zn(II) and Cu(II) followed the pseudo-second-order model with adsorption rate constant 4.9 x 10-2 and 3.14 g.mg-1.min-1, respectively. The both adsorption processes obeyed Langmuir isotherm with adsorption capacity of 2.03 and 2.42 mg.g-1 of adsorbent, respectively. The strength of Zn adsorption on Ca-alginate immobilized activated rice bran (86.63%) was more effective compared to Ca-alginate beads (60.96%) and activated rice bran (43.85%). The strength of Cu adsorption was 80.00%, 61.50% and 22.10%, respectively. The desorption of Zn(II) and Cu(II) showed that recovery percentage of the adsorption was 76.56% and 57.80% with the condition of using HCl 0.1 M as desorption agent for 1 hour.

  16. Rat vas deferens SERCA2 is modulated by Ca{sup 2+}/calmodulin protein kinase II-mediated phosphorylation

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, J.B.R.; Muzi-Filho, H. [Programa de Farmacologia e Inflamação, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ (Brazil); Valverde, R.H.F. [Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ (Brazil); Quintas, L.E.M. [Programa de Farmacologia e Inflamação, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ (Brazil); Noel, F. [Programa de Desenvolvimento de Fármacos, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ (Brazil); Einicker-Lamas, M. [Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ (Brazil); Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ (Brazil); Cunha, V.M.N. [Programa de Farmacologia e Inflamação, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ (Brazil)

    2013-03-19

    Ca{sup 2+} pumps are important players in smooth muscle contraction. Nevertheless, little information is available about these pumps in the vas deferens. We have determined which subtype of sarco(endo)plasmic reticulum Ca{sup 2+}-ATPase isoform (SERCA) is expressed in rat vas deferens (RVD) and its modulation by calmodulin (CaM)-dependent mechanisms. The thapsigargin-sensitive Ca{sup 2+}-ATPase from a membrane fraction containing the highest SERCA levels in the RVD homogenate has the same molecular mass (∼115 kDa) as that of SERCA2 from the rat cerebellum. It has a very high affinity for Ca{sup 2+} (Ca{sub 0.5} = 780 nM) and a low sensitivity to vanadate (IC{sub 50} = 41 µM). These facts indicate that SERCA2 is present in the RVD. Immunoblotting for CaM and Ca{sup 2+}/calmodulin-dependent protein kinase II (CaMKII) showed the expression of these two regulatory proteins. Ca{sup 2+} and CaM increased serine-phosphorylated residues of the 115-kDa protein, indicating the involvement of CaMKII in the regulatory phosphorylation of SERCA2. Phosphorylation is accompanied by an 8-fold increase of thapsigargin-sensitive Ca{sup 2+} accumulation in the lumen of vesicles derived from these membranes. These data establish that SERCA2 in the RVD is modulated by Ca{sup 2+} and CaM, possibly via CaMKII, in a process that results in stimulation of Ca{sup 2+} pumping activity.

  17. Thermodynamics of calmodulin trapping by Ca2+/calmodulin-dependent protein kinase II: subpicomolar Kd determined using competition titration calorimetry.

    Science.gov (United States)

    Tse, Joyce K Y; Giannetti, Anthony M; Bradshaw, J Michael

    2007-04-03

    Calmodulin (CaM) trapping by Ca2+/calmodulin-dependent protein kinase II (CaMKII) is a phenomenon whereby the affinity of CaM for CaMKII increases >1000-fold following CaMKII autophosphorylation. The molecular basis of this effect is not entirely understood. Binding of CaM to the phosphorylated and the unphosphorylated states of CaMKII is well mimicked by the interaction of CaM with two different length peptides taken from the CaM-binding region of CaMKII, peptides we refer to as the long and intermediate peptides. To better understand the conformational change accompanying CaM trapping, we have used isothermal titration calorimetry (ITC) to compare the binding thermodynamics of CaM to these peptides as well as to a shorter CaMKII-based peptide. Calorimetric analysis revealed that the enthalpy, rather than the entropy, distinguished binding of these three peptides. Furthermore, the heat capacity change was found to be similar for the long and intermediate peptides but smaller in magnitude for the short peptide. Direct titration of CaM with peptide provided the Kd value for the short peptide (Kd = 5.9 +/- 2.4 microM), but a novel, two-phased competitive binding strategy was necessary to ascertain the affinities of the intermediate (Kd = 0.17 +/- 0.06 nM) and long (Kd = 0.07 +/- 0.04 pM) peptides. To our knowledge, the Kd for the long peptide is the most potent measured to date using ITC. Together, the findings reported here support a model whereby the final conformational change accompanying CaM trapping buries little additional surface area but does involve formation of new hydrogen bonds and van der Waals contacts that contribute to formation of the high-affinity, CaM-trapped state.

  18. Selective chelation of Cd(II) and Pb(II) versus Ca(II) and Zn(II) by using octadentate ligands containing pyridinecarboxylate and pyridyl pendants.

    Science.gov (United States)

    Ferreirós-Martínez, Raquel; Esteban-Gómez, David; Platas-Iglesias, Carlos; de Blas, Andrés; Rodríguez-Blas, Teresa

    2009-12-07

    Herein we report the coordination properties toward Cd(II), Pb(II), Ca(II), and Zn(II) of a new octadentate ligand (py-H(2)bcpe) based on a ethane-1,2-diamine unit containing two picolinate and two pyridyl pendants, which is structurally derived from the previous reported ligand bcpe. Potentiometric studies have been carried out to determine the protonation constants of the ligand and the stability constants of the complexes with these cations. The introduction of the pyridyl pendants in bcpe provokes a very important increase of the logK(ML) values obtained for the Pb(II) and Cd(II) complexes, while this effect is less important in the case of the Zn(II) analogue. As a result, py-bcpe shows a certain selectivity for Cd(II) and Pb(II) over Zn(II) while keeping good Pb(II)/Ca(II) and Cd(II)/Ca(II) selectivities, and the new receptor py-bcpe can be considered as a new structural framework for the design of novel Cd(II) and Pb(II) extracting agents. Likewise, the stabilities of the Cd(II) and Pb(II) complexes are higher than those of the corresponding EDTA analogues. The X-ray crystal structure of [Zn(py-bcpe)] shows hexadentate binding of the ligand to the metal ion, the coordination polyhedron being best described as a severely distorted octahedron. However, the X-ray crystal structure of the Pb(II) analogue shows octadentate binding of the ligand to the metal ion. A detailed investigation of the structure in aqueous solution of the complexes by using nuclear magnetic resonance (NMR) techniques and density functional theory (DFT) calculations (B3LYP) shows that while in the Zn(II) complex the metal ion is six-coordinated, in the Pb(II) and Ca(II) analogues the metal ions are eight-coordinated. For the Cd(II) complex, our results suggest that in solution the complex exists as a mixture of seven- and eight-coordinated species. DFT calculations performed both in the gas phase and in aqueous solution have been also used to investigate the role of the Pb(II) lone pair in

  19. Slender Ca II H fibrils mapping magnetic fields in the low solar chromosphere

    CERN Document Server

    Jafarzadeh, Shahin; Solanki, S K; Wiegelmann, T; Riethmueller, T; van Noort, M; Szydlarski, M; Rodriguez, J Blanco; Barthol, P; Iniesta, J C del Toro; Gandorfer, A; Gizon, L; Hirzberger, J; Knoelker, M; Pillet, V Martinez; Suarez, D Orozco; Schmidt, W

    2016-01-01

    A dense forest of slender bright fibrils near a small solar active region is seen in high-quality narrow-band Ca II H images from the SuFI instrument onboard the Sunrise balloon-borne solar observatory. The orientation of these slender Ca II H fibrils (SCF) overlaps with the magnetic field configuration in the low solar chromosphere derived by magnetostatic extrapolation of the photospheric field observed with Sunrise/IMaX and SDO/HMI. In addition, many observed SCFs are qualitatively aligned with small-scale loops computed from a novel inversion approach based on best-fit numerical MHD simulation. Such loops are organized in canopy-like arches over quiet areas that differ in height depending on the field strength near their roots.

  20. A Century of Solar Ca ii Measurements and Their Implication for Solar UV Driving of Climate

    Science.gov (United States)

    Foukal, Peter; Bertello, Luca; Livingston, William C.; Pevtsov, Alexei A.; Singh, Jagdev; Tlatov, Andrey G.; Ulrich, Roger K.

    2009-04-01

    Spectroheliograms and disk-integrated flux monitoring in the strong resonance line of Ca ii (K line) provide the longest record of chromospheric magnetic plages. We compare recent reductions of the Ca ii K spectroheliograms obtained since 1907 at the Kodaikanal, Mt. Wilson, and US National Solar Observatories. Certain differences between the individual plage indices appear to be caused mainly by differences in the spectral passbands used. Our main finding is that the indices show remarkably consistent behavior on the multidecadal time scales of greatest interest to global warming studies. The reconstruction of solar ultraviolet flux variation from these indices differs significantly from the 20th-century global temperature record. This difference is consistent with other findings that, although solar UV irradiance variation may affect climate through influence on precipitation and storm tracks, its significance in global temperature remains elusive.

  1. Radiative emission of solar features in the Ca II K line: comparison of measurements and models

    CERN Document Server

    Ermolli, I; Uitenbroek, H; Giorgi, F; Rast, M P; Solanki, S K

    2010-01-01

    We study the radiative emission of various types of solar features, such as quiet Sun, enhanced network, plage, and bright plage regions, identified on filtergrams taken in the Ca II K line. We analysed fulldisk images obtained with the PSPT, by using three interference filters that sample the Ca II K line with different bandpasses. We studied the dependence of the radiative emission of disk features on the filter bandpass. We also performed a NLTE spectral synthesis of the Ca II K line integrated over the bandpass of PSPT filters. The synthesis was carried out by utilizing both the PRD and CRD with the most recent set of semi­empirical atmosphere models in the literature and some earlier atmosphere models. We measured the CLV of intensity values for various solar features identified on PSPT images and compared the results obtained with those derived from the synthesis. We find that CRD calculations derived using the most recent quiet Sun model, on average, reproduce the measured values of the quiet Sun regi...

  2. Long-term Synoptic Observations of Ca II K and Magnetic Flux

    Science.gov (United States)

    Bertello, L.; Pevtsov, A. A.; Tlatov, A. G.

    2016-04-01

    Long-term synoptic observations in the resonance line of Ca II K and measurements of the solar magnetic flux over several decades constitute a fundamental database for a variety of retrospective analyzes of the state of the solar magnetism. These data archives may also hold the key for untangling some of the mysteries behind the solar dynamo, which in turn could result in a better predictive capability of current dynamo models. Synoptic Ca II K observations began in 1907 at the Kodaikanal observatory (India) and in 1915 at the Mt Wilson (California, USA) solar observatory. By the early 1970s a number of synoptic programs for solar magnetic observations were established that provided full disk magnetograms. These programs include measurements carried out at the Mt Wilson 150-foot solar tower, Wilcox observatory (California, USA), and by the National Solar Observatory (NSO, USA). Today the NSO is continuing these observations through its Synoptic Optical Long-term Investigations of the Sun (SOLIS) facility. We will review some of these historical observations, their properties, and their importance for understanding the behavior of the solar magnetic field over multidecadal time scales. We will also show recent results about using Ca II K spectroheliograms and sunspot magnetic field measurements to reconstruct homogeneous series of pseudo-magnetograms prior the magnetograph era.

  3. Ca II H sunspot tomography from the photosphere to the chromosphere

    Science.gov (United States)

    Henriques, V. M. J.; Kiselman, D.

    2013-09-01

    Aims: We aim at gaining insight into the thermal properties of different small-scale structures related to sunspots. Methods: We use filtergrams in the Ca ii H filter at the Swedish 1-m Solar Telescope to study the relationship between fine structure at different heights in a sunspot. Results: The methods for destretching and aligning the different image data work well. The magnetic spine structure in the outer parts of the sunspot penumbra is found to be associated with higher intensities in the Ca ii H wing passbands but with less steep vertical temperature gradients. Dark lanes in a light bridge behave very similarly to dark cores in penumbral filaments. Fibril structures are seen in the line-core images over the umbra and penumbra. Conclusions: The observations add support to the idea that penumbral filaments, light bridges, and umbral dots are caused by similar processes of overturning convection. Observations in the Ca ii H & K wings are a promising observable, complementing others, for testing simulation results for sunspots at high spatial resolution.

  4. Porous heterometallic Cd(II)-Ca(II)-terephthalate: Synthesis, structure, luminescent and gas adsorption properties

    Science.gov (United States)

    Liu, Haiping; Dong, Yanli; Ren, Hailiang

    2016-03-01

    A new heterometallic poly(dihydrate-one and a half terephthalate-cadmium calcium) coordination polymer, namely [CdCa(pdc)1.5(H2O)2]n (1, H2pdc = terephthalic acid), has been successfully obtained by the solvothermal reactions of H2pdc, Cd(NO3)2·4H2O and Ca(NO3)2·4H2O. Single crystal X-ray diffraction analysis reveals that compound 1 features a 3D porous framework based on 1D chain subunits. Moreover, compound 1 is luminescent and exhibits high adsorption capacities for H2, CH4 and CO2 at room temperature.

  5. Calcium EXAFS establishes the Mn-Ca cluster in the oxygen-evolving complex of Photosystem II

    Energy Technology Data Exchange (ETDEWEB)

    Cinco, Roehl M.; McFarlane Holman, Karen L.; Robblee, John H.; Yano, Junko; Pizarro, Shelly A.; Bellacchio, Emanuele; Sauer, Kenneth; Yachandra, Vittal K.

    2002-08-02

    The proximity of Ca to the Mn cluster of the photosynthetic water-oxidation complex is demonstrated by X-ray absorption spectroscopy. We have collected EXAFS data at the Ca K-edge using active PS II membrane samples that contain approximately 2 Ca per 4 Mn. These samples are much less perturbed than previously investigated Sr-substituted samples, which were prepared subsequent to Ca depletion. The new Ca EXAFS clearly shows backscattering from Mn at 3.4 angstroms, a distance that agrees with that surmised from previously recorded Mn EXAFS. This result is also consistent with earlier related experiments at the Sr K-edge, using samples that contained functional Sr, that show Mn is {approx}; 3.5 angstroms distant from Sr. The totality of the evidence clearly advances the notion that the catalytic center of oxygen evolution is a Mn-Ca heteronuclear cluster.

  6. Ca2+ -regulated lysosome fusion mediates angiotensin II-induced lipid raft clustering in mesenteric endothelial cells.

    Science.gov (United States)

    Han, Wei-Qing; Chen, Wen-Dong; Zhang, Ke; Liu, Jian-Jun; Wu, Yong-Jie; Gao, Ping-Jin

    2016-04-01

    It has been reported that intracellular Ca2+ is involved in lysosome fusion and membrane repair in skeletal cells. Given that angiotensin II (Ang II) elicits an increase in intracellular Ca2+ and that lysosome fusion is a crucial mediator of lipid raft (LR) clustering, we hypothesized that Ang II induces lysosome fusion and activates LR formation in rat mesenteric endothelial cells (MECs). We found that Ang II acutely increased intracellular Ca2+ content, an effect that was inhibited by the extracellular Ca2+ chelator ethylene glycol tetraacetic acid (EGTA) and the inositol 1,4,5-trisphosphate (IP3)-induced Ca2+ release inhibitor 2-aminoethoxydiphenyl borate (2-APB). Further study showed that EGTA almost completely blocked Ang II-induced lysosome fusion, the translocation of acid sphingomyelinase (ASMase) to LR clusters, ASMase activation and NADPH (nicotinamide adenine dinucleotide phosphate) oxidase activation. In contrast, 2-APB had a slight inhibitory effect. Functionally, both the lysosome inhibitor bafilomycin A1 and the ASMase inhibitor amitriptyline reversed Ang II-induced impairment of vasodilation. We conclude that Ca2+ -regulated lysosome fusion mediates the Ang II-induced regulation of the LR-redox signaling pathway and mesenteric endothelial dysfunction.

  7. Mechanochemical synthesis and intercalation of Ca(II)Fe(III)-layered double hydroxides

    Energy Technology Data Exchange (ETDEWEB)

    Ferencz, Zs.; Szabados, M.; Varga, G.; Csendes, Z. [Department of Organic Chemistry, University of Szeged, Dóm tér 8, Szeged H-6720 (Hungary); Materials and Solution Structure Research Group, Institute of Chemistry, University of Szeged, Aradi Vértanúk tere 1, Szeged H-6720 (Hungary); Kukovecz, Á. [Department of Applied and Environmental Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720 (Hungary); MTA-SZTE “Lendület” Porous Nanocomposites Research Group, Rerrich Béla tér 1, Szeged H-6720 (Hungary); Kónya, Z. [Department of Applied and Environmental Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720 (Hungary); MTA-SZTE Reaction Kinetics and Surface Chemistry Research Group, Rerrich Béla tér 1, Szeged H-6720 (Hungary); Carlson, S. [MAX IV Laboratory, Ole Römers väg 1, Lund SE-223 63 (Sweden); Sipos, P. [Materials and Solution Structure Research Group, Institute of Chemistry, University of Szeged, Aradi Vértanúk tere 1, Szeged H-6720 (Hungary); Department of Inorganic and Analytical Chemistry, University of Szeged, Dóm tér 7, Szeged H-6720 (Hungary); and others

    2016-01-15

    A mechanochemical method (grinding the components without added water – dry grinding, followed by further grinding in the presence of minute amount of water or NaOH solution – wet grinding) was used in this work for the preparation and intercalation of CaFe-layered double hydroxides (LDHs). Both the pristine LDHs and the amino acid anion (cystinate and tyrosinate) intercalated varieties were prepared by the two-step grinding procedure in a mixer mill. By systematically changing the conditions of the preparation method, a set of parameters could be determined, which led to the formation of close to phase-pure LDH. The optimisation procedure was also applied for the intercalation processes of the amino acid anions. The resulting materials were structurally characterised by a range of methods (X-ray diffractometry, scanning electron microscopy, energy dispersive analysis, thermogravimetry, X-ray absorption and infra-red spectroscopies). It was proven that this simple mechanochemical procedure was able to produce complex organic–inorganic nanocomposites: LDHs intercalated with amino acid anions. - Graphical abstract: Amino acid anion-Ca(II)Fe(III)-LDHs were successfully prepared by a two-step milling procedure. - Highlights: • Synthesis of pristine and amino acid intercalated CaFe-LDHs by two-step milling. • Identifying the optimum synthesis and intercalation parameters. • Characterisation of the samples with a range of instrumental methods.

  8. Study of the Sextans dwarf spheroidal galaxy from the DART CaII triplet survey

    CERN Document Server

    Battaglia, G; Helmi, A; Irwin, M; Parisi, P; Hill, V; Jablonka, P

    2010-01-01

    We use VLT/FLAMES intermediate resolution (R~6500) spectra of individual red giant branch stars in the near-infrared CaII triplet (CaT) region to investigate the wide-area metallicity properties and internal kinematics of the Sextans dwarf spheroidal galaxy (dSph). Our final sample consists of 174 probable members of Sextans with accurate line-of-sight velocities (+- 2 km/s) and CaT [Fe/H] measurements (+- 0.2 dex). We use the MgI line at 8806.8 \\AA\\, as an empirical discriminator for distinguishing between probable members of the dSph (giant stars) and probable Galactic contaminants (dwarf stars). Sextans shows a similar chemo-dynamical behaviour to other Milky Way dSphs, with its central regions being more metal rich than the outer parts and with the more metal-rich stars displaying colder kinematics than the more metal-poor stars. Hints of a velocity gradient are found along the projected major axis and along an axis at P.A.=191 deg, however a larger and more spatially extended sample may be necessary to p...

  9. The [Fe/H] Dependence on the Ca {\\sc ii}-$M_V$ Relationship

    CERN Document Server

    Gomez, Thomas; Pancino, Elena

    2012-01-01

    We examined the Wilson-Bappu effect, a relationship between the absolute magnitude of the star, $M_V$, and the logarithm of the Ca {\\sc ii} emission width, $W_0$, over the largest $M_V$ range to date, +13 to -5, covering M-dwarfs to type Ia supergiants. We used an extensive literature, the latest Hipparcos reduction, data from two globular clusters, and new observations from Apache Point Observatory to compile a sample that allowed us to study the effect of [Fe/H] on the Wilson-Bappu relationship. Our results include reporting the deviations from linearity and demonstrating that the Wilson-Bappu relationship is insensitive to metallicity.

  10. On the migration of Ca II H bright points in the internetwork

    CERN Document Server

    Jafarzadeh, S; Solanki, S K; Pietarila, A; Feller, A; Lagg, A; Gandorfer, A

    2014-01-01

    The migration of magnetic bright point-like features (MBP) in the lower solar atmosphere reflects the dispersal of magnetic flux as well as the horizontal flows of the atmospheric layer they are embedded in. We analyse trajectories of the proper motion of intrinsically magnetic, isolated internetwork Ca II H MBPs (mean lifetime 461 +- 9 sec) to obtain their diffusivity behaviour. We use seeing-free high spatial and temporal resolution image sequences of quiet-Sun, disc-centre observations obtained in the Ca II H 3968 {\\AA} passband of the Sunrise Filter Imager (SuFI) onboard the Sunrise balloon-borne solar observatory. Small MBPs in the internetwork are automatically tracked. The trajectory of each MBP is then calculated and described by a diffusion index ({\\gamma}) and a diffusion coefficient (D). We further explore the distribution of the diffusion indices with the help of a Monte Carlo simulation. We find {\\gamma} = 1.69 +- 0.08 and D = 257 +- 32 km^2/s averaged over all MBPs. Trajectories of most MBPs are...

  11. Ca II H and K Chromospheric Emission Lines in Late K and M Dwarfs

    CERN Document Server

    Rauscher, E; Marcy, Geoffrey W.; Rauscher, Emily

    2006-01-01

    We have measured the profiles of the Ca II H and K chromospheric emission lines in 147 main sequence stars of spectral type M5-K7 (0.30-0.55 solar masses) using multiple high resolution spectra obtained during six years with the HIRES spectrometer on the Keck 1 telescope. Remarkably, the average FWHM, equivalent widths, and line luminosities of Ca II H and K increase by a factor of 3 with increasing stellar mass over this small range of stellar masses. We fit the H and K lines with a double Gaussian model to represent both the chromospheric emission and the non-LTE central absorption. Most of the sample stars display a central absorption that is typically redshifted by ~0.1 km/s relative to the emission, but the nature of this velocity gradient remains unknown. The FWHM of the H and K lines increase with stellar luminosity, reminiscent of the Wilson-Bappu effect in FGK-type stars. Both the equivalent widths and FWHM exhibit modest temporal variability in individual stars. At a given value of M_v, stars exhibi...

  12. Butterfly Diagram and Carrington Maps for Century-Long Ca II K Spectroheliograms from Kodaikanal Observatory

    CERN Document Server

    Chatterjee, Subhamoy; Ravindra, B

    2016-01-01

    The century-long (1907-2007) Ca II K spectroheliograms from Kodaikanal Solar Observatory (KSO) are calibrated, processed and analysed in the present study to follow the evolution of bright on disc structures called plages, the possible representatives of magnetic activity on the Sun. This has been the longest dataset studied in Ca II K till date covering about 9.5 cycles of 11 year periods. Plages were segmented with area $\\geq 1\\:\\textrm {arcmin}^2$ using global thresholds for individual full disc images and subsequent application of morphological closing operation. Plage index was calculated and seen to have close positive correlation with fractional disc area covered by plages. The newly generated plage area cycle (from KSO) was compared with the same from Mount Wilson observatory (Correlation~$95.6\\%$) for the overlapping years i.e. 1915-2000. Study illustrated time-latitude distribution of plage centroids rendering butterfly diagram (as observed for sunspots). The 3D visualisation of the diagram showed o...

  13. Dynamo Sensitivity in Solar Analogs with 50 Years of Ca II H & K Activity

    CERN Document Server

    Egeland, Ricky; Baliunas, Sallie; Hall, Jeffrey C; Pevtsov, Alexei A; Henry, Gregory W

    2016-01-01

    The Sun has a steady 11-year cycle in magnetic activity most well-known by the rising and falling in the occurrence of dark sunspots on the solar disk in visible bandpasses. The 11-year cycle is also manifest in the variations of emission in the Ca II H & K line cores, due to non-thermal (i.e. magnetic) heating in the lower chromosphere. The large variation in Ca II H & K emission allows for study of the patterns of long-term variability in other stars thanks to synoptic monitoring with the Mount Wilson Observatory HK photometers (1966-2003) and Lowell Observatory Solar-Stellar Spectrograph (1994-present). Overlapping measurements for a set of 27 nearby solar-analog (spectral types G0-G5) stars were used to calibrate the two instruments and construct time series of magnetic activity up to 50 years in length. Precise properties of fundamental importance to the dynamo are available from Hipparcos, the Geneva-Copenhagen Survey, and CHARA interferometry. Using these long time series and measurements of fu...

  14. The Appearance of Spicules in High Resolution Observations of Ca II H and Hα

    Science.gov (United States)

    Pereira, Tiago M. D.; Rouppe van der Voort, Luc; Carlsson, Mats

    2016-06-01

    Solar spicules are chromospheric fibrils that appear everywhere on the Sun, yet their origin is not understood. Using high resolution observations of spicules obtained with the Swedish 1 m Solar Telescope, we aim to understand how spicules appear in filtergrams and Dopplergrams, how they compare in Ca ii H and Hα filtergrams, and what can make them appear and disappear. We find that spicules display a rich and detailed spatial structure, and show a distribution of transverse velocities that, when aligned with the line of sight, can make them appear at different Hα wing positions. They become more abundant at positions closer to the line core, reflecting a distribution of Doppler shifts and widths. In Hα width maps they stand out as bright features both on disk and off limb, reflecting their large Doppler motions and possibly higher temperatures than in the typical Hα formation region. Spicule lifetimes measured from narrowband images at only a few positions will be an underestimate because Doppler shifts can make them disappear prematurely from such images; for such cases, width maps are a more robust tool. In Hα and Ca ii H filtergrams, off-limb spicules essentially have the same properties, appearance, and evolution. We find that the sudden appearance of spicules can be explained by Doppler shifts from their transverse motions, and does not require other convoluted explanations.

  15. Transverse oscillations in slender Ca II H fibrils observed with Sunrise/SuFI

    CERN Document Server

    Jafarzadeh, Shahin; Gafeira, R; van Noort, M; Barthol, P; Rodriguez, J Blanco; Iniesta, J C del Toro; Gandorfer, A; Gizon, L; Hirzberger, J; Knoelker, M; Suarez, D Orozco; Riethmueller, T L; Schmidt, W

    2016-01-01

    We present observations of transverse oscillations in slender Ca II H fibrils (SCFs) in the lower solar chromosphere. We use a 1-hour long time series of high (spatial and temporal) resolution, seeing-free observations in a 0.11 nm wide passband covering the line core of Ca II H 396.9 nm from the second flight of the Sunrise balloon-borne solar observatory. The entire field of view, spanning the polarity inversion line of an active region close to the solar disk center, is covered with bright, thin, and very dynamic fine structures. Our analysis reveals the prevalence of transverse waves in SCFs with median amplitudes and periods on the order of 2.4+-0.8 km/s and 83+-29 s, respectively (with standard deviations given as uncertainties). We find that the transverse waves often propagate along (parts of) the SCFs with median phase speeds of 9+-14 km/s. While the propagation is only in one direction along the axis in some of the SCFs, propagating waves in both directions, as well as standing waves are also observ...

  16. Spectropolarimetric observations of the Ca II 8498 A and 8542 A lines in the quiet Sun

    CERN Document Server

    Pietarila, A; Bogdan, T

    2007-01-01

    The Ca II infrared triplet is one of the few magnetically sensitive chromospheric lines available for ground-based observations. We present spectropolarimetric observations of the 8498 A and 8542 A lines in a quiet Sun region near a decaying active region and compare the results with a simulation of the lines in a high plasma-beta regime. Cluster analysis of Stokes V profile pairs shows that the two lines, despite arguably being formed fairly close, often do not have similar shapes. In the network, the local magnetic topology is more important in determining the shapes of the Stokes V profiles than the phase of the wave, contrary to what our simulations show. We also find that Stokes V asymmetries are very common in the network, and the histograms of the observed amplitude and area asymmetries differ significantly from the simulation. Both the network and internetwork show oscillatory behavior in the Ca II lines. It is stronger in the network, where shocking waves, similar to those in the high-beta simulation...

  17. Composite CaWO4 Detectors for the CRESST-II Experiment

    CERN Document Server

    Kiefer, M; Bauer, M; Bavykina, I; Bento, A; Brown, A; Bucci, C; Ciemniak, C; Coppi, C; Deuter, G; von Feilitzsch, F; Hauff, D; Henry, S; Huff, P; Imber, J; Ingleby, S; Isaila, C; Jochum, J; Kimmerle, M; Kraus, H; Lanfranchi, J -C; Lang, R F; Malek, M; McGowan, R; Mikhailik, V B; Pantic, E; Petricca, F; Pfister, S; Potzel, W; Pröbst, F; Roth, S; Rottler, K; Sailer, C; Schäffner, K; Schmaler, J; Scholl, S; Seidel, W; Stodolsky, L; Tolhurst, A J B; Usherov, I; Westphal, W

    2009-01-01

    CRESST-II, standing for Cryogenic Rare Events Search with Superconducting Thermometers phase II, is an experiment searching for Dark Matter. In the LNGS facility in Gran Sasso, Italy, a cryogenic detector setup is operated in order to detect WIMPs by elastic scattering off nuclei, generating phononic lattice excitations and scintillation light. The thermometers used in the experiment consist of a tungsten thin-film structure evaporated onto the CaWO4 absorber crystal. The process of evaporation causes a decrease in the scintillation light output. This, together with the need of a big-scale detector production for the upcoming EURECA experiment lead to investigations for producing thermometers on smaller crystals which are glued onto the absorber crystal. In our Run 31 we tested composite detectors for the first time in the Gran Sasso setup. They seem to produce higher light yields as hoped and could provide an additional time based discrimination mechanism for low light yield clamp events.

  18. An ultra fast detection method reveals strain-induced Ca(2+) entry via TRPV2 in alveolar type II cells.

    Science.gov (United States)

    Fois, Giorgio; Wittekindt, Oliver; Zheng, Xing; Felder, Erika Tatiana; Miklavc, Pika; Frick, Manfred; Dietl, Paul; Felder, Edward

    2012-09-01

    A commonly used technique to investigate strain-induced responses of adherent cells is culturing them on an elastic membrane and globally stretching the membrane. However, it is virtually impossible to acquire microscopic images immediately after the stretch with this method. Using a newly developed technique, we recorded the strain-induced increase of the cytoplasmic Ca(2+) concentration ([Ca(2+)](c)) in rat primary alveolar type II (ATII) cells at an acquisition rate of 30ms and without any temporal delay. We can show that the onset of the mechanically induced rise in [Ca(2+)](c) was very fast (<30 ms), and Ca(2+) entry was immediately abrogated when the stimulus was withdrawn. This points at a direct mechanical activation of an ion channel. RT-PCR revealed high expression of TRPV2 in ATII cells, and silencing TRPV2, as well as blocking TRPV channels with ruthenium red, significantly reduced the strain-induced Ca(2+) response. Moreover, the usually homogenous pattern of the strain-induced [Ca(2+)](c) increase was converted into a point-like response after both treatments. Also interfering with actin/myosin and integrin binding inhibited the strain-induced increase of [Ca(2)](c). We conclude that TRPV2 participates in strain-induced Ca(2+) entry in ATII cells and suggest a direct mechanical activation of the channel that depends on FAs and actin/myosin. Furthermore, our results underline the importance of cell strain systems that allow high temporal resolution.

  19. Stimulation of fibroblast proliferation by neokyotorphin requires Ca influx and activation of PKA, CaMK II and MAPK/ERK.

    Science.gov (United States)

    Sazonova, Olga V; Blishchenko, Elena Yu; Tolmazova, Anna G; Khachin, Dmitry P; Leontiev, Konstantin V; Karelin, Andrey A; Ivanov, Vadim T

    2007-01-01

    Neokyotorphin [TSKYR, hemoglobin alpha-chain fragment (137-141)] has previously been shown to enhance fibroblast proliferation, its effect depending on cell density and serum level. Here we show the dependence of the effect of neokyotorphin on cell type and its correlation with the effect of protein kinase A (PKA) activator 8-Br-cAMP, but not the PKC activator 4beta-phorbol 12-myristate, 13-acetate (PMA). In L929 fibroblasts, the proliferative effect of neokyotorphin was suppressed by the Ca2+ L-type channel inhibitors verapamil or nifedipine, the intracellular Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester, kinase inhibitors H-89 (PKA), KN-62 (Ca2+/calmodulin-dependent kinase II) and PD98059 (mitogen-activated protein kinase). The proliferative effect of 8-Br-cAMP was also suppressed by KN-62 and PD98059. PKC suppression (downregulation with PMA or inhibition with bisindolylmaleimide XI) did not affect neokyotorphin action. The results obtained point to a cAMP-like action for neokyotorphin.

  20. Relationship between breakthrough curve and adsorption isotherm of Ca(II) imprinted chitosan microspheres for metal adsorption

    Institute of Scientific and Technical Information of China (English)

    Yangcheng Lu; Jing He; Longwen Wu; Guangsheng Luo

    2016-01-01

    In this work, an equilibrium-dispersion model was successfully established to describe the breakthrough performance of Ca(II) imprinted chitosan (Ca(II)-CS) microspheres packed column for metal adsorption, and the assumptions of Langmuir isotherms and axial dispersion controlled mass transfer process were confirmed. The axial dispersion coefficient in Ca(II)-CS microspheres packed column was found to be almost proportional to the linear velocity and fit for prediction through single breakthrough test. Sensitivity analysis for breakthrough curve indicated the axial dispersion coefficient as well as Langmuir coefficient was sensitive variable for deep removal requirement. The retrieval of the adsorption isotherms of Ca(II)-CS microspheres from breakthrough curve was fulfilled by model ing calibration. A strategy based on the correlation between adsorption isotherms and breakthrough performance was further proposed to simplify the column adsorption design using absorbents with smal/uniform size and fast adsorption kinetics like Ca(II)-CS microspheres to cut down the gap between lab and industry.

  1. Enhancement of CA3 hippocampal network activity by activation of group II metabotropic glutamate receptors.

    Science.gov (United States)

    Ster, Jeanne; Mateos, José María; Grewe, Benjamin Friedrich; Coiret, Guyllaume; Corti, Corrado; Corsi, Mauro; Helmchen, Fritjof; Gerber, Urs

    2011-06-14

    Impaired function or expression of group II metabotropic glutamate receptors (mGluRIIs) is observed in brain disorders such as schizophrenia. This class of receptor is thought to modulate activity of neuronal circuits primarily by inhibiting neurotransmitter release. Here, we characterize a postsynaptic excitatory response mediated by somato-dendritic mGluRIIs in hippocampal CA3 pyramidal cells and in stratum oriens interneurons. The specific mGluRII agonists DCG-IV or LCCG-1 induced an inward current blocked by the mGluRII antagonist LY341495. Experiments with transgenic mice revealed a significant reduction of the inward current in mGluR3(-/-) but not in mGluR2(-/-) mice. The excitatory response was associated with periods of synchronized activity at theta frequency. Furthermore, cholinergically induced network oscillations exhibited decreased frequency when mGluRIIs were blocked. Thus, our data indicate that hippocampal responses are modulated not only by presynaptic mGluRIIs that reduce glutamate release but also by postsynaptic mGluRIIs that depolarize neurons and enhance CA3 network activity.

  2. Chromospheric Sunspot Oscillations in H-alpha and Ca II 8542A

    CERN Document Server

    Maurya, Ram Ajor; Park, Hyungmin; Yang, Heesu; Song, Donguk; Cho, Kyuhyoun

    2013-01-01

    We study chromospheric oscillations including umbral flashes and running penumbral waves in a sunspot of active region (AR) using scanning spectroscopy in H-alpha and Ca II 8542A, with the Fast Imaging Solar Spectrograph (FISS) at the 1.6 meter New Solar Telescope at Big Bear Solar Observatory. A bisector method is applied to spectral observations to construct chromospheric Doppler velocity maps. Temporal sequence analysis of these shows enhanced high-frequency oscillations inside the sunspot umbra in both lines. Their peak frequency gradually decreases outward from the umbra. The oscillation power is found to be associated with magnetic-field strength and inclination, with different relationships in different frequency bands.

  3. The Hanle and Zeeman polarization signals of the solar Ca II 8542 \\AA\\ line

    CERN Document Server

    Štěpán, Jiří

    2016-01-01

    We highlight the main results of a three-dimensional (3D) multilevel radiative transfer investigation about the solar disk-center polarization of the Ca {\\sc ii} 8542 \\AA\\ line. First, we investigate the linear polarization due to the atomic level polarization produced by the absorption and scattering of anisotropic radiation in a 3D model of the solar atmosphere, taking into account the symmetry breaking effects caused by its thermal, dynamic and magnetic structure. Second, we study the contribution of the Zeeman effect to the linear and circular polarization. Finally, we show examples of the Stokes profiles produced by the joint action of atomic level polarization and the Hanle and Zeeman effects. We find that the Zeeman effect tends to dominate the linear polarization signals only in the localized patches of opposite magnetic polarity where the magnetic field is relatively strong and slightly inclined, while outside such very localized patches the linear polarization is often dominated by the contribution ...

  4. Chromospheric diagnosis with Ca II lines: forward modeling in forward scattering (I)

    CERN Document Server

    Carlin, E S

    2014-01-01

    This paper shows the first synthetic tomography of the quiet solar chromosphere formed by spatial maps of scattering polarization. It has been calculated for the CaII 8498, 8542 and 3934 A lines by solving the NLTE (non-local thermodynamical equilibrium) RT (radiative transfer) problem of the second kind in a 3D atmosphere model obtained from realistic MHD (magneto-hydrodynamical) simulations. Maps of circular polarization were calculated neglecting atomic polarization. Our investigation focuses on the linear polarization signals induced by kinematics, radiation field anisotropy and Hanle effect in forward-scattering geometry. Thus, instead of considering slit profiles at the limb as normally done in the study of the second solar spectrum, we synthetize and analyze spatial maps of polarization at disk center. It allows us to understand the spatial signatures of dynamics and magnetic field in the linear polarization for discriminating them observationally. Our results suggest new ideas for chromospheric diagno...

  5. ADSORPTION OF Ca(II FROM AQUEOUS SOLUTION ONTO CELLULOSIC FIBERS AND ITS IMPACT ON THE PAPERMAKING PROCESS

    Directory of Open Access Journals (Sweden)

    Guangxiang Yuan

    2011-06-01

    Full Text Available Calcium(II is one of the most common metal ions in papermaking systems. However, the effect of Ca2+ on papermaking processes has not drawn much attention. The adsorption of Ca2+ from aqueous solutions onto bleached Eucalyptus globulus kraft pulp fibers was investigated. Thermodynamic results indicate that the adsorption of Ca2+ onto bleached E. globulus kraft pulp fibers was exothermic, reversible, and spontaneous. The equilibrium data followed Langmuir isotherms. The adsorption basically agrees with the ionic reaction model between carboxyl groups of fibers and Ca2+ in which the molar ratio of carboxyl to Ca2+ is close to 2:1. The binding capacity with carboxyl groups is so strong that the anionic charge of the adsorption sites in fibers can be screened, leading to decreased performance of cationic polyacrylamide for retention and drainage, Alkyl Ketene Dimer (AKD for sizing, and cationic starch for dry strength. The precipitation effect of Ca2+ with three kinds of dissolved and colloidal substances (sodium rosinate, sodium stearate, sodium oxalate also was investigated. The results showed that deposits formed by Ca2+ and dissolved and colloidal substances, which could adsorb to the surfaces of fibers, would affect drainage and retention abilities of cationic polyacrylamide.

  6. Pavlovian fear conditioning regulates Thr286 autophosphorylation of Ca2+/calmodulin-dependent protein kinase II at lateral amygdala synapses.

    Science.gov (United States)

    Rodrigues, Sarina M; Farb, Claudia R; Bauer, Elizabeth P; LeDoux, Joseph E; Schafe, Glenn E

    2004-03-31

    Ca2+/calmodulin-dependent protein kinase II (CaMKII) plays a critical role in synaptic plasticity and memory formation in a variety of learning systems and species. The present experiments examined the role of CaMKII in the circuitry underlying pavlovian fear conditioning. First, we reveal by immunocytochemical and tract-tracing methods that alphaCaMKII is postsynaptic to auditory thalamic inputs and colocalized with the NR2B subunit of the NMDA receptor. Furthermore, we show that fear conditioning results in an increase of the autophosphorylated (active) form of alphaCaMKII in lateral amygdala (LA) spines. Next, we demonstrate that intra-amygdala infusion of a CaMK inhibitor, 1-[NO-bis-1,5-isoquinolinesulfonyl]-N-methyl-l-tyrosyl-4-phenylpiperazine, KN-62, dose-dependently impairs the acquisition, but not the expression, of auditory and contextual fear conditioning. Finally, in electrophysiological experiments, we demonstrate that an NMDA receptor-dependent form of long-term potentiation at thalamic input synapses to the LA is impaired by bath application of KN-62 in vitro. Together, the results of these experiments provide the first comprehensive view of the role of CaMKII in the amygdala during fear conditioning.

  7. SYNTHESIS, CHARACTERIZATION AND ANTITUMOR ACTIVITY OF A Ca (II COORDINATION POLYMER BASED ON 3-AMINO-2-PYRAZINECARBOXYLIC ACID

    Directory of Open Access Journals (Sweden)

    XI-SHI TAI

    2015-10-01

    Full Text Available A new Ca(II coordination polymer has been obtained by reaction of Ca(ClO42·H2O with 3-amino-2-pyrazinecarboxylic acid in CH3CH2OH/H2O. It was characterized by IR, 1HNMR, thermal analysis and X-ray single crystal diffraction analysis. X-ray analysis reveals that each Ca(II center is seven-coordination with a N2O5 distorted pentagonal bipyramidal coordination environment. The Ca(II ions are linked through the O atoms of 3-amino-2-pyrazinecarboxylic acid ligands to form 1D chain structure. And then a 3D network structure is constructed by hydrogen bonds and π-π stacking. The antitumor activity of 3-amino-2-pyrazinecarboxylic acid ligand and its Ca(II coordination polymer against human intestinal adenocarcinoma HCT-8 cells, lung adenocarcinoma HCT-116 cells and human lung adenocarcinoma A549 cells line have been investigated.

  8. Alkyl sulfonic acide hydrazides: Synthesis, characterization, computational studies and anticancer, antibacterial, anticarbonic anhydrase II (hCA II) activities

    Science.gov (United States)

    O. Ozdemir, Ummuhan; İlbiz, Firdevs; Balaban Gunduzalp, Ayla; Ozbek, Neslihan; Karagoz Genç, Zuhal; Hamurcu, Fatma; Tekin, Suat

    2015-11-01

    Methane sulfonic acide hydrazide, CH3SO2NHNH2 (1), ethane sulfonic acide hydrazide, CH3CH2SO2NHNH2 (2), propane sulfonic acide hydrazide, CH3CH2CH2SO2NHNH2 (3) and butane sulfonic acide hydrazide, CH3CH2CH2CH2SO2NHNH2 (4) have been synthesized as homologous series and characterized by using elemental analysis, spectrophotometric methods (1H-13C NMR, FT-IR, LC-MS). In order to gain insight into the structure of the compounds, we have performed computational studies by using 6-311G(d, p) functional in which B3LYP functional were implemented. The geometry of the sulfonic acide hydrazides were optimized at the DFT method with Gaussian 09 program package. A conformational analysis of compounds were performed by using NMR theoretical calculations with DFT/B3LYP/6-311++G(2d, 2p) level of theory by applying the (GIAO) approach. The anticancer activities of these compounds on MCF-7 human breast cancer cell line investigated by comparing IC50 values. The antibacterial activities of synthesized compounds were studied against Gram positive bacteria; Staphylococcus aureus ATCC 6538, Bacillus subtilis ATCC 6633, Bacillus cereus NRRL-B-3711, Enterococcus faecalis ATCC 29212 and Gram negative bacteria; Escherichia coli ATCC 11230, Pseudomonas aeruginosa ATCC 15442, Klebsiella pneumonia ATCC 70063 by using the disc diffusion method. The inhibition activities of these compounds on carbonic anhydrase II enzyme (hCA II) have been investigated by comparing IC50 and Ki values. The biological activity screening shows that butane sulfonic acide hydrazide (4) has more activity than the others against tested breast cancer cell lines MCF-7, Gram negative/Gram positive bacteria and carbonic anhydrase II (hCA II) isoenzyme.

  9. Urotensin II induction of neonatal cardiomyocyte hypertrophy involves the CaMKII/PLN/SERCA 2a signaling pathway.

    Science.gov (United States)

    Shi, Hongtao; Han, Qinghua; Xu, Jianrong; Liu, Wenyuan; Chu, Tingting; Zhao, Li

    2016-05-25

    Although studies have shown that Urotensin II (UII) can induce cardiomyocyte hypertrophy and UII-induced cardiomyocyte hypertrophy model has been widely used for hypertrophy research, but its precise mechanism remains unknown. Recent researches have demonstrated that UII-induced cardiomyocyte hypertrophy has a relationship with the changes of intracellular Ca(2+) concentration. Therefore, the aim of this study was to investigate the mechanisms of cardiomyocyte hypertrophy induced by UII and to explore whether the calcium/calmodulin-dependent protein kinase II (CaMKII)-mediated up-regulating of phospholamban (PLN) Thr17-phosphorylation signaling pathway contributed to UII-induced cardiomyocyte hypertrophy. Primary cultures of neonatal rat cardiomyocytes were stimulated for 48h with UII. Cell size, protein/DNA contents and intracellular Ca(2+) were determined. Phosphorylated and total forms of CaMKII, PLN and the total amount of serco/endo-plasmic reticulum ATPases (SERCA 2a) were quantified by western blot. The responses of cardiomyocytes to UII were also evaluated after pretreatment with the CaMKII inhibitor, KN-93. These results showed that UII increased cell size, protein/DNA ratio and intracellular Ca(2+), consistent with a hypertrophic response. Furthermore, the phosphorylation of CaMKII and its downstream target PLN (Thr17), SERCA 2a levels were up-regulated by UII treatment. Conversely, treatment with KN-93 reversed all those effects of UII. Taken together, the results suggest that UII can induce cardiomyocyte hypertrophy through CaMKII-mediated up-regulating of PLN Thr17-phosphorylation signaling pathway.

  10. A DFT-Based QSARs Study of Acetazolamide/Sulfanilamide Derivatives with Carbonic Anhydrase (CA-II Isozyme Inhibitory Activity

    Directory of Open Access Journals (Sweden)

    Oral Oltulu

    2007-02-01

    Full Text Available This study presents Quantitative Structure Activity Relationships (QSAR studyon a pool of 18 bio-active sulfonamide compounds which includes five acetazolamidederivatives, eight sulfanilamide derivatives and five clinically used sulfonamides moleculesas drugs namely acetazolamide, methazolamide, dichlorophenamide, ethoxolamide anddorzolamide. For all the compounds, initial geometry optimizations were carried out with amolecular mechanics (MM method using the MM force fields. The lowest energyconformations of the compounds obtained by the MM method were further optimized by theDensity Functional Theory (DFT method by employing Becke’s three-parameter hybridfunctional (B3LYP and 6-31G (d basis set. Molecular descriptors, dipole moment,electronegativity, total energy at 0 K, entropy at 298 K, HOMO and LUMO energiesobtained from DFT calculations provide valuable information and have a significant role inthe assessment of carbonic anhydrase (CA-II inhibitory activity of the compounds. By usingthe multiple linear regression technique several QSAR models have been drown up with thehelp these calculated descriptors and carbonic anhydrase (CA-II inhibitory data of themolecules. Among the obtained QSAR models presented in the study, statistically the mostsignificant one is a five parameters linear equation with the squared correlation coefficient R2 values of ca. 0.94 and the squared cross-validated correlation coefficient R2CV values of ca. 0.85. The results were discussed in the light of the main factors that influence theinhibitory activity of the carbonic anhydrase (CA-II isozyme.

  11. Shaping of action potentials by type I and type II large-conductance Ca²+-activated K+ channels.

    Science.gov (United States)

    Jaffe, D B; Wang, B; Brenner, R

    2011-09-29

    The BK channel is a Ca(2+) and voltage-gated conductance responsible for shaping action potential waveforms in many types of neurons. Type II BK channels are differentiated from type I channels by their pharmacology and slow gating kinetics. The β4 accessory subunit confers type II properties on BK α subunits. Empirically derived properties of BK channels, with and without the β4 accessory subunit, were obtained using a heterologous expression system under physiological ionic conditions. These data were then used to study how BK channels alone (type I) and with the accessory β4 subunit (type II) modulate action potential properties in biophysical neuron models. Overall, the models support the hypothesis that it is the slower kinetics provided by the β4 subunit that endows the BK channel with type II properties, which leads to broadening of action potentials and, secondarily, to greater recruitment of SK channels reducing neuronal excitability. Two regions of parameter space distinguished type II and type I effects; one where the range of BK-activating Ca(2+) was high (>20 μM) and the other where BK-activating Ca(2+) was low (∼0.4-1.2 μM). The latter required an elevated BK channel density, possibly beyond a likely physiological range. BK-mediated sharpening of the spike waveform associated with the lack of the β4 subunit was sensitive to the properties of voltage-gated Ca(2+) channels due to electrogenic effects on spike duration. We also found that depending on Ca(2+) dynamics, type II BK channels may have the ability to contribute to the medium AHP, a property not generally ascribed to BK channels, influencing the frequency-current relationship. Finally, we show how the broadening of action potentials conferred by type II BK channels can also indirectly increase the recruitment of SK-type channels decreasing the excitability of the neuron.

  12. The Ca²⁺-calmodulin-Ca²⁺/calmodulin-dependent protein kinase II signaling pathway is involved in oxidative stress-induced mitochondrial permeability transition and apoptosis in isolated rat hepatocytes.

    Science.gov (United States)

    Toledo, Flavia D; Pérez, Leonardo M; Basiglio, Cecilia L; Ochoa, Justina E; Sanchez Pozzi, Enrique J; Roma, Marcelo G

    2014-09-01

    Oxidative stress (OS) is a common event in most hepatopathies, leading to mitochondrial permeability transition pore (MPTP) formation and further exacerbation of both OS from mitochondrial origin and cell death. Intracellular Ca²⁺ increase plays a permissive role in these events, but the underlying mechanisms are poorly known. We examined in primary cultured rat hepatocytes whether the Ca²⁺/calmodulin (CaM)-dependent protein kinase II (CaMKII) signaling pathway is involved in this process, by using tert-butyl hydroperoxide (tBOOH) as a pro-oxidant, model compound. tBOOH (500 μM, 15 min) induced MPTP formation, as assessed by measuring mitochondrial membrane depolarization as a surrogate marker, and increased lipid peroxidation in a cyclosporin A (CsA)-sensitive manner, revealing the involvement of MPTPs in tBOOH-induced radical oxygen species (ROS) formation. Intracellular Ca²⁺ sequestration with BAPTA/AM, CaM blockage with W7 or trifluoperazine, and CaMKII inhibition with KN-62 all fully prevented tBOOH-induced MPTP opening and reduced tBOOH-induced lipid peroxidation to a similar extent to CsA, suggesting that Ca²⁺/CaM/CaMKII signaling pathway fully mediates MPTP-mediated mitochondrial ROS generation. tBOOH-induced apoptosis, as shown by flow cytometry of annexin V/propidium iodide, mitochondrial release of cytochrome c, activation of caspase-3 and increase in the Bax-to-Bcl-xL ratio, and the Ca²⁺/CaM/CaMKII signaling antagonists fully prevented these effects. Intramitochondrial CaM and CaMKII were partially involved in tBOOH-induced MPTP formation, since W7 and KN-62 both attenuated the tBOOH-induced, MPTP-mediated swelling of isolated mitochondria. We concluded that Ca²⁺/CaM/CaMKII signaling pathway is a key mediator of OS-induced MPTP formation and the subsequent exacerbation of OS from mitochondrial origin and apoptotic cell death.

  13. The octopamine receptor OAMB mediates ovulation via Ca2+/calmodulin-dependent protein kinase II in the Drosophila oviduct epithelium.

    Directory of Open Access Journals (Sweden)

    Hyun-Gwan Lee

    Full Text Available Ovulation is an essential physiological process in sexual reproduction; however, the underlying cellular mechanisms are poorly understood. We have previously shown that OAMB, a Drosophila G-protein-coupled receptor for octopamine (the insect counterpart of mammalian norepinephrine, is required for ovulation induced upon mating. OAMB is expressed in the nervous and reproductive systems and has two isoforms (OAMB-AS and OAMB-K3 with distinct capacities to increase intracellular Ca2+ or intracellular Ca2+ and cAMP in vitro. Here, we investigated tissue specificity and intracellular signals required for OAMB's function in ovulation. Restricted OAMB expression in the adult oviduct epithelium, but not the nervous system, reinstated ovulation in oamb mutant females, in which either OAMB isoform was sufficient for the rescue. Consistently, strong immunoreactivities for both isoforms were observed in the wild-type oviduct epithelium. To delineate the cellular mechanism by which OAMB regulates ovulation, we explored protein kinases functionally interacting with OAMB by employing a new GAL4 driver with restricted expression in the oviduct epithelium. Conditional inhibition of Ca2+/Calmodulin-dependent protein kinase II (CaMKII, but not protein kinase A or C, in the oviduct epithelium inhibited ovulation. Moreover, constitutively active CaMKII, but not protein kinase A, expressed only in the adult oviduct epithelium fully rescued the oamb female's phenotype, demonstrating CaMKII as a major downstream molecule conveying the OAMB's ovulation signal. This is consistent with the ability of both OAMB isoforms, whose common intracellular signal in vitro is Ca2+, to reinstate ovulation in oamb females. These observations reveal the critical roles of the oviduct epithelium and its cellular components OAMB and CaMKII in ovulation. It is conceivable that the OAMB-mediated cellular activities stimulated upon mating are crucial for secretory activities suitable for egg

  14. Fluxes in H\\alpha and Ca II H and K for a sample of Southern stars

    CERN Document Server

    Cincunegui, C; Mauas, P J D; Cincunegui, Carolina; D\\'iaz, Rodrigo F.; Mauas, Pablo J. D.

    2007-01-01

    The main chromospheric activity indicator is the S index, which is esentially the ratio of the flux in the core of the Ca II H and K lines to the continuum nearby, and is well studied basically for stars from F to K. Another usual chromospheric proxy is the H\\alpha line, which is beleived to be tightly correlated with the Ca II index. In this work we characterize both chromospheric activity indicators, one associated with the H and K Ca II lines and the other with H\\alpha, for the whole range of late type stars, from F to M. We present periodical medium-resolution echelle observations covering the complete visual range, which were taken at the CASLEO Argentinean Observatory. These observations are distributed along 7 years. We use a total of 917 flux-calibrated spectra for 109 stars which range from F6 to M5. We statistically study these two indicators for stars of different activity levels and spectral types. We directly derive the conversion factor which translate the known S index to flux in the Ca II core...

  15. The NIR Ca II triplet at low metallicity : Searching for extremely low-metallicity stars in classical dwarf galaxies

    NARCIS (Netherlands)

    Starkenburg, E.; Hill, V.; Tolstoy, E.; Gonzalez Hernandez, J.I.; Irwin, M.; Helmi, A.; Battaglia, G.; Jablonka, P.; Tafelmeyer, M.; Shetrone, M.; Venn, K.; de Boer, T.

    2010-01-01

    The NIR Ca II triplet absorption lines have proven to be an important tool for quantitative spectroscopy of individual red giant branch stars in the Local Group, providing a better understanding of metallicities of stars in the Milky Way and dwarf galaxies and thereby an opportunity to constrain the

  16. Heme-induced Trypanosoma cruzi proliferation is mediated by CaM kinase II

    Energy Technology Data Exchange (ETDEWEB)

    Souza, C.F. [Laboratorio de Imunomodulacao e Protozoologia, Instituto Oswaldo Cruz, Fiocruz (Brazil); Carneiro, A.B.; Silveira, A.B. [Laboratorio de Sinalizacao Celular, Instituto de Bioquimica Medica, UFRJ (Brazil); Laranja, G.A.T. [Laboratorio de Interacao Tripanosomatideos e Vetores, Departamento de Bioquimica, IBRAG, UERJ, 20551-030 Rio de Janeiro (Brazil); Silva-Neto, M.A.C. [Laboratorio de Sinalizacao Celular, Instituto de Bioquimica Medica, UFRJ (Brazil); INCT, Entomologia Molecular (Brazil); Costa, S.C. Goncalves da [Laboratorio de Imunomodulacao e Protozoologia, Instituto Oswaldo Cruz, Fiocruz (Brazil); Paes, M.C., E-mail: mcpaes@uerj.br [Laboratorio de Interacao Tripanosomatideos e Vetores, Departamento de Bioquimica, IBRAG, UERJ, 20551-030 Rio de Janeiro (Brazil); INCT, Entomologia Molecular (Brazil)

    2009-12-18

    Trypanosoma cruzi, the etiologic agent of Chagas disease, is transmitted through triatomine vectors during their blood-meal on vertebrate hosts. These hematophagous insects usually ingest approximately 10 mM of heme bound to hemoglobin in a single meal. Blood forms of the parasite are transformed into epimastigotes in the crop which initiates a few hours after parasite ingestion. In a previous work, we investigated the role of heme in parasite cell proliferation and showed that the addition of heme significantly increased parasite proliferation in a dose-dependent manner . To investigate whether the heme effect is mediated by protein kinase signalling pathways, parasite proliferation was evaluated in the presence of several protein kinase (PK) inhibitors. We found that only KN-93, a classical inhibitor of calcium-calmodulin-dependent kinases (CaMKs), blocked heme-induced cell proliferation. KN-92, an inactive analogue of KN-93, was not able to block this effect. A T. cruzi CaMKII homologue is most likely the main enzyme involved in this process since parasite proliferation was also blocked when Myr-AIP, an inhibitory peptide for mammalian CaMKII, was included in the cell proliferation assay. Moreover, CaMK activity increased in parasite cells with the addition of heme as shown by immunological and biochemical assays. In conclusion, the present results are the first strong indications that CaMKII is involved in the heme-induced cell signalling pathway that mediates parasite proliferation.

  17. On-disk counterparts of type II spicules in the Ca II 854.2 nm and Halpha lines

    CERN Document Server

    van der Voort, L Rouppe; De Pontieu, B; Carlsson, M; Vissers, G

    2009-01-01

    Recently a second type of spicules was discovered at the solar limb with the Solar Optical Telescope (SOT) onboard the Japanese Hinode spacecraft. These previously unrecognized type II spicules are thin chromospheric jets that are shorter-lived (10-60 s) and that show much higher apparent upward velocities (of order 50-100 km/s) than the classical spicules. Since they have been implicated in providing hot plasma to coronal loops, their formation, evolution and properties are important ingredients for a better understanding of the mass and energy balance of the low solar atmosphere. Here we report on the discovery of the disk counterparts of type II spicules using spectral imaging data in the Ca II 854.2 nm and Halpha lines with the CRisp Imaging SpectroPolarimeter (CRISP) at the Swedish Solar Telescope (SST) in La Palma. We find rapid blueward excursions in the line profiles of both chromospheric lines that correspond to thin, jet-like features that show apparent velocities of order 50 km/s. These blueward ex...

  18. The Ca(2+)/Calmodulin/CaMKK2 Axis: Nature's Metabolic CaMshaft.

    Science.gov (United States)

    Marcelo, Kathrina L; Means, Anthony R; York, Brian

    2016-10-01

    Calcium (Ca(2+)) is an essential ligand that binds its primary intracellular receptor calmodulin (CaM) to trigger a variety of downstream processes and pathways. Central to the actions of Ca(2+)/CaM is the activation of a highly conserved Ca(2+)/CaM kinase (CaMK) cascade that amplifies Ca(2+) signals through a series of subsequent phosphorylation events. Proper regulation of Ca(2+) flux is necessary for whole-body metabolism and disruption of Ca(2+) homeostasis has been linked to various metabolic diseases. Here we provide a synthesis of recent advances that highlight the roles of the Ca(2+)/CaMK axis in key metabolic tissues. An appreciation of this information is critical to understanding the mechanisms by which Ca(2+)/CaM-dependent signaling contributes to metabolic homeostasis and disease.

  19. Chromospheric Diagnosis with Ca II Lines: Forward Modeling in Forward Scattering. I

    Science.gov (United States)

    Carlin, E. S.; Asensio Ramos, A.

    2015-03-01

    This paper presents a synthetic tomography of the quiet solar chromosphere formed by spatial maps of scattering polarization. It has been calculated for the Ca II 8498, 8542, and 3934 Å lines by solving the non-LTE radiative transfer problem of the second kind in a three-dimensional atmosphere model obtained from realistic magneto-hydrodynamical simulations. Our investigation focuses on the linear polarization signals induced by kinematics, radiation field anisotropy, and the Hanle effect in forward-scattering geometry. Thus, instead of considering slit profiles at the limb as normally done in the study of the second solar spectrum, we synthesize and analyze spatial maps of polarization at the disk center. This allows us to understand the spatial signatures of dynamics and magnetic field in the linear polarization in order to discriminate them observationally. Our results suggest some ideas for chromospheric diagnosis that will be developed throughout a series of papers. In particular, Hanle polarity inversion lines and dynamic Hanle diagrams are two concepts introduced in the present work. We find that chromospheric dynamics and magnetic field topology create spatial polarization fingerprints that trace the dynamic situation of the plasma and the magnetic field. This allows us to reconstruct the magnetic field intensity in the middle chromosphere using Stokes V along grooves of null linear polarization. We finally address the problems of diagnosing Hanle saturation and kinematic amplification of scattering signals using Hanle diagrams.

  20. A STIS Atlas of CaII Triplet Absorption Line Kinematics in Galactic Nuclei

    CERN Document Server

    Batcheldor, D; Valluri, M; Mandalou, J; Merritt, D

    2013-01-01

    The relations observed between supermassive black holes and their host galaxies suggest a fundamental link in the processes that cause these two objects to evolve. A more comprehensive understanding of these relations could be gained by increasing the number of supermassive black hole mass (M) measurements. This can be achieved, in part, by continuing to model the stellar dynamics at the centers of galactic bulges using data of the highest possible spatial resolution. Consequently, we present here an atlas of galaxies in the Space Telescope Imaging Spectrograph (STIS) data archive that may have spectra suitable for new M estimates. Archived STIS G750M data for all non-barred galactic bulges are co-aligned and combined, where appropriate, and the radial signal-to-noise ratios calculated. The line-of-sight velocity distributions from the CaII triplet are then determined using a maximum penalized likelihood method. We find 19 out of 42 galaxies may provide useful new M estimates since they are found to have data...

  1. Observational Searches for Chromospheric -Mode Oscillations from CaII H-Line Observations

    Indian Academy of Sciences (India)

    R. Kariyappa; L. Damé; K. M. Hiremath

    2006-06-01

    We have used a high spatial and temporal resolution of long time sequence of spectra in CaII H-line obtained at the Vacuum Tower Telescope (VTT) of the Sacramento Peak Observatory on a quiet region at the center of the solar disk over a large number of bright points and network elements to search for atmospheric (chromospheric) -mode oscillations. An important parameter of the H-line profile, intensity at H2V(IH2V), has been derived from a large number of line profiles. We derived the light curves of all the bright points and network elements. The light curves represent the main pulse with large intensity amplitude and followed by several follower pulses with lower intensity amplitudes. The light curves of these bright points would give an impression that one can as well draw curves towards and away from the highest peak (main pulse) showing an exponential growth and decay of the amplitudes. An exponential decaying function has been fitted for all the light curves of the bright points to determine the damping time of the modes that are more or less the same, and one value of the coefficient of exponent can represent reasonably well the decay for all the cases. The FFT analysis of temporal variation of both the bright points and the network elements indicates around 10-min periodicity. We speculate that this longer period of oscillation may be related to chromospheric -mode oscillations.

  2. The Appearance of Spicules in High Resolution Observations of Ca II H and H-alpha

    CERN Document Server

    Pereira, Tiago M D; Carlsson, Mats

    2016-01-01

    Solar spicules are chromospheric fibrils that appear everywhere on the Sun, yet their origin is not understood. Using high resolution observations of spicules obtained with the Swedish 1-m Solar Telescope we aim to understand how spicules appear in filtergrams and Dopplergrams, how they compare in Ca II H and H-alpha, and what can make them appear and disappear. We find spicules display a rich and detailed spatial structure, and show a distribution of transverse velocities that when aligned with the line of sight can make them appear at different H-alpha wing positions. They become more abundant at positions closer to the line core, reflecting a distribution of Doppler shifts and widths. In H-alpha width maps they stand out as bright features both on disk and off-limb, reflecting their large Doppler motions and possibly higher temperatures than in the typical H-alpha formation region. Spicule lifetimes measured from narrowband images at only a few positions will be an underestimate because Doppler shifts can ...

  3. Ca II triplet spectroscopy of RGB stars in NGC 6822: kinematics and metallicities

    CERN Document Server

    Swan, Jesse; Tolstoy, Eline; Irwin, Mike J

    2016-01-01

    We present a detailed analysis of the chemistry and kinematics of red giants in the dwarf irregular galaxy NGC 6822. Spectroscopy at 8500 Angstroms was acquired for 72 red giant stars across two fields using FORS2 at the VLT. Line of sight extinction was individually estimated for each target star to accommodate the variable reddening across NGC 6822. The mean radial velocity was found to be v_helio = (52.8 +/- 2.2) km/s with dispersion rms = 24.1 km/s, in agreement with other studies. Ca II triplet equivalent widths were converted into [Fe/H] metallicities using a V magnitude proxy for surface gravity. The average metallicity was [Fe/H] = (-0.84 +/- 0.04) with dispersion rms = 0.31 dex and interquartile range 0.48. Our assignment of individual reddening values makes our analysis more sensitive to spatial variations in metallicity than previous studies. We divide our sample into metal-rich and metal-poor stars; the former are found to cluster towards small radii with the metal-poor stars more evenly distribut...

  4. Ca(II) Binding Regulates and Dominates the Reactivity of a Transition-Metal-Ion-Dependent Diesterase from Mycobacterium tuberculosis.

    Science.gov (United States)

    Pedroso, Marcelo M; Larrabee, James A; Ely, Fernanda; Gwee, Shuhui E; Mitić, Nataša; Ollis, David L; Gahan, Lawrence R; Schenk, Gerhard

    2016-01-18

    The diesterase Rv0805 from Mycobacterium tuberculosis is a dinuclear metallohydrolase that plays an important role in signal transduction by controlling the intracellular levels of cyclic nucleotides. As Rv0805 is essential for mycobacterial growth it is a promising new target for the development of chemotherapeutics to treat tuberculosis. The in vivo metal-ion composition of Rv0805 is subject to debate. Here, we demonstrate that the active site accommodates two divalent transition metal ions with binding affinities ranging from approximately 50 nm for Mn(II) to about 600 nm for Zn(II) . In contrast, the enzyme GpdQ from Enterobacter aerogenes, despite having a coordination sphere identical to that of Rv0805, binds only one metal ion in the absence of substrate, thus demonstrating the significance of the outer sphere to modulate metal-ion binding and enzymatic reactivity. Ca(II) also binds tightly to Rv0805 (Kd ≈40 nm), but kinetic, calorimetric, and spectroscopic data indicate that two Ca(II) ions bind at a site different from the dinuclear transition-metal-ion binding site. Ca(II) acts as an activator of the enzymatic activity but is able to promote the hydrolysis of substrates even in the absence of transition-metal ions, thus providing an effective strategy for the regulation of the enzymatic activity.

  5. Empirical calibration of the near-IR Ca II triplet - I. The stellar library and index definition

    CERN Document Server

    Cenarro, A J; Gorgas, J; Peletier, R F; Vazdekis, A; Prada, F

    2001-01-01

    A new stellar library at the near-IR spectral region developed for the empirical calibration of the Ca II triplet and stellar population synthesis modeling is presented. The library covers the range 8348-9020 Angstrom at 1.5 Angstrom (FWHM) spectral resolution, and consists of 706 stars spanning a wide range in atmospheric parameters. We have defined a new set of near-IR indices, CaT*, CaT and PaT, which mostly overcome the limitations of previous definitions, the former being specially suited for the measurement of the Ca II triplet strength corrected for the contamination from Paschen lines. We also present a comparative study of the new and the previous calcium indices, as well as the corresponding transformations between the different systems. A thorough analysis of the sources of index errors and the procedure to calculate them is given. Finally, index and error measurements for the whole stellar library are provided together with the final spectra.

  6. Ca II 854.2 nm Spectromagnetograms: A Powerful Chromospheric Diagnostic

    Science.gov (United States)

    Harvey, J. W.; Bertello, Luca; Branston, D.; Britanik, J.; Bulau, S.; Cole, L.; Gosain, Sanjay; Harker, Brian; Jones, Harrison P.; Marble, A.; Martinez Pillet, V.; Pevtsov, A.; Schramm, K.; Streander, Kim; Villegas, H.

    2016-05-01

    The transition from physical dominance by plasma flows in the photosphere to magnetic pressure in the solar chromosphere motivates as many diagnostic observations as possible across this important region. Among the few ground-accessible spectral lines formed within the chromosphere, the Ca II 854.2 nm line has the desirable properties of presence everywhere on the solar disk, Zeeman sensitivity, and narrow line width. Mapped observations of circular polarization within this line (spectromagnetograms) have been made at NSO infrequently since 1974, with regular daily full-disk observations starting in August 1996. Full-disk spectral observations of the complete Stokes polarization vector are now being made regularly since November 2015. It is not easy to estimate chromospheric magnetic field properties from the 854.2 nm line profile polarization. To provide rough quick-look vector field maps we found that the weak-field approximation provides a fair first estimate of the line-of-sight component but appears to be too simple to interpret the transverse magnetic field from frequently asymmetric, linearly-polarized line profiles. More realistic estimates of the chromospheric vector field, short of extremely lengthy, full 3D, non-local radiative transfer inversions, are being investigated. We briefly introduce recent instrumental modifications and observational characteristics, sample observations, and results concerning the expansion of the chromospheric field with increasing height, the presence of large areas of weak, nearly horizontal fields, and field estimates in plages, sunspots, flares, filaments, and filament channels. The Stokes spectra will be freely available to the community.This work utilizes SOLIS data obtained by the NSO Integrated Synoptic Program (NISP), managed by the National Solar Observatory, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc. under a cooperative agreement with the National Science Foundation.

  7. Ca II triplet spectroscopy of RGB stars in NGC 6822: kinematics and metallicities

    Science.gov (United States)

    Swan, J.; Cole, A. A.; Tolstoy, E.; Irwin, M. J.

    2016-03-01

    We present a detailed analysis of the chemistry and kinematics of red giants in the dwarf irregular galaxy NGC 6822. Spectroscopy at ≈8500 Å was acquired for 72 red giant stars across two fields using FORS2 at the VLT. Line-of-sight extinction was individually estimated for each target star to accommodate the variable reddening across NGC 6822. The mean radial velocity was found to be = -52.8 ± 2.2 km s-1 with dispersion σv = 24.1 km s-1, in agreement with other studies. Ca II triplet equivalent widths were converted into [Fe/H] metallicities using a V magnitude proxy for surface gravity. The average metallicity was = -0.84 ± 0.04 with dispersion σ = 0.31 dex and interquartile range 0.48. Our assignment of individual reddening values makes our analysis more sensitive to spatial variations in metallicity than previous studies. We divide our sample into metal-rich and metal-poor stars; the former were found to cluster towards small radii with the metal-poor stars more evenly distributed across the galaxy. The velocity dispersion of the metal-poor stars was found to be higher than that of the metal-rich stars (σ _{v_MP}=27.4 km s-1; σ _{v_MR}=21.1 km s-1); combined with the age-metallicity relation this indicates that the older populations have either been dynamically heated during their lifetimes or were born in a less disc-like distribution than the younger stars.. The low ratio vrot/σv suggests that within the inner 10 arcmin, NGC 6822's stars are dynamically decoupled from the H I gas, and possibly distributed in a thick disc or spheroid structure.

  8. Active Calcium/Calmodulin-Dependent Protein Kinase II (CaMKII Regulates NMDA Receptor Mediated Postischemic Long-Term Potentiation (i-LTP by Promoting the Interaction between CaMKII and NMDA Receptors in Ischemia

    Directory of Open Access Journals (Sweden)

    Ning Wang

    2014-01-01

    Full Text Available Active calcium/calmodulin-dependent protein kinase II (CaMKII has been reported to take a critical role in the induction of long-term potentiation (LTP. Changes in CaMKII activity were detected in various ischemia models. It is tempting to know whether and how CaMKII takes a role in NMDA receptor (NMDAR-mediated postischemic long-term potentiation (NMDA i-LTP. Here, we monitored changes in NMDAR-mediated field excitatory postsynaptic potentials (NMDA fEPSPs at different time points following ischemia onset in vitro oxygen and glucose deprivation (OGD ischemia model. We found that 10 min OGD treatment induced significant i-LTP in NMDA fEPSPs, whereas shorter (3 min or longer (25 min OGD treatment failed to induce prominent NMDA i-LTP. CaMKII activity or CaMKII autophosphorylation displays a similar bifurcated trend at different time points following onset of ischemia both in vitro OGD or in vivo photothrombotic lesion (PT models, suggesting a correlation of increased CaMKII activity or CaMKII autophosphorylation with NMDA i-LTP. Disturbing the association between CaMKII and GluN2B subunit of NMDARs with short cell-permeable peptides Tat-GluN2B reversed NMDA i-LTP induced by OGD treatment. The results provide support to a notion that increased interaction between NMDAR and CaMKII following ischemia-induced increased CaMKII activity and autophosphorylation is essential for induction of NMDA i-LTP.

  9. Complexin II plays a positive role in Ca2+-triggered exocytosis by facilitating vesicle priming

    DEFF Research Database (Denmark)

    Cai, Haijiang; Reim, Kerstin; Varoqueaux, Frederique

    2008-01-01

    the complex and inhibiting membrane fusion. However, several other studies also suggest that CPXs are positive regulators of neurotransmitter release. Thus, whether CPXs are positive or negative regulators of exocytosis is not known, much less the stage in the vesicle life cycle at which they function. Here...... regulate the size of the primed vesicle pools and have a positive role in Ca(2+)-triggered exocytosis....

  10. A Butterfly Diagram and Carrington Maps for Century-long CA II K Spectroheliograms from The Kodaikanal Observatory

    Science.gov (United States)

    Chatterjee, Subhamoy; Banerjee, Dipankar; Ravindra, B.

    2016-08-01

    The century-long (1907-2007) Ca ii K spectroheliograms from the Kodaikanal Solar Observatory (KSO) are calibrated, processed, and analyzed to follow the evolution of the bright on-disc structures called plages, possible representatives of magnetic activity on the Sun. This is the longest data set studied in Ca ii K to date, covering about 9.5 cycles of 11 yr periods. Plages are segmented with area ≥slant 1 {{arcmin}}2 using global thresholds for individual full disc images and subsequent application of a morphological closing operation. The plage index is calculated and is seen to have a close positive correlation with the fractional disc area covered by plages. The newly generated plage area cycle (from KSO) was compared with the same from the Mount Wilson Observatory (correlation 95.6%) for the overlapping years, i.e., 1915-2000. This study illustrates the time-latitude distribution of plage centroids by rendering a butterfly diagram (as observed for sunspots). The 3D visualization of the diagram shows one-to-one mapping between plage location, time, and area. This work further delineates the positional correlation between magnetic patches and plage regions through the comparison of synoptic maps derived from both KSO Ca ii K images and space-based full disc line-of-sight magnetograms. Regular synoptic magnetograms from ground-based observatories are available only after 1970s. Thus the long term Ca ii K data from KSO can be used as a proxy for estimating magnetic activity locations and their strengths at earlier times.

  11. The behaviour of the excess CaII H & K and H$\\varepsilon$ emissions in chromospherically active binaries

    CERN Document Server

    Montes, D; Cornide, M; De Castro, E

    1995-01-01

    In this work we analyze the behaviour of the excess Ca~{\\sc ii} H \\& K and H\\epsilon emissions in a sample of 73 chromospherically active binary systems (RS~CVn and BY~Dra classes), of different activity levels and luminosity classes. This sample includes the 53 stars analyzed by Fern\\'andez-Figueroa et al. (1994) and the observations of 28 systems described by Montes et al. (1995c). By using the spectral subtraction technique (subtraction of a synthesized stellar spectrum constructed from reference stars of spectral type and luminosity class similar to those of the binary star components) we obtain the active-chromosphere contribution to the Ca~{\\sc ii} H \\& K lines in these 73 systems. We have determined the excess Ca~{\\sc ii} H \\& K emission equivalent widths and converted them into surface fluxes. The emissions arising from each component were obtained when it was possible to deblend both contributions. We have found that the components of active binaries are generally stronger emitters than s...

  12. 有关CA

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ 什么是CA? CA(Certificaton Authority)是认证机构的国际通称,是指对数字证书的申请者发放、管理、取消数字证书的机构.CA的作用是检查证书持有者身份的合法性,并签发证书(在证书上签字),以防证书被伪造或篡改.

  13. Simulations of the Mg II k and Ca II 8542 lines from an Alfv\\'en Wave-heated flare chromosphere

    CERN Document Server

    Kerr, Graham S; Russell, Alexander J B; Allred, Joel C

    2016-01-01

    We use radiation hydrodynamic simulations to examine two models of solar flare chromospheric heating: Alfv\\'en wave dissipation and electron beam collisional losses. Both mechanisms are capable of strong chromospheric heating, and we show that the distinctive atmospheric evolution in the mid-to-upper chromosphere results in Mg II k-line emission that should be observably different between wave-heated and beam-heated simulations. We also present Ca II 8542A profiles which are formed slightly deeper in the chromosphere. The Mg II k-line profiles from our wave-heated simulation are quite different from those from a beam-heated model and are more consistent with IRIS observations. The predicted differences between the Ca II 8542A in the two models are small. We conclude that careful observational and theoretical study of lines formed in the mid-to-upper chromosphere holds genuine promise for distinguishing between competing models for chromospheric heating in flares.

  14. Spectroscopic characterization of the competitive binding of Eu(III), Ca(II), and Cu(II) to a sedimentary originated humic acid

    Energy Technology Data Exchange (ETDEWEB)

    Marang, L.; Reiller, P.E. [CEA Saclay, Nucl Energy Div, DPC SECR, Lab Speciat Radionucleides and Mol, 91 - Gif sur Yvette (France); Marang, L.; Benedetti, M.F. [Univ Paris 07, Lab Geochim Eaux, IPGP UMR CNRS 7154, F-75205 Paris 13 (France); Eidner, S.; Kumke, M.U. [Univ Potsdam, Inst Chem, D-14476 Potsdam (Germany)

    2009-06-15

    The competition between REE, alkaline earth and d-transition metals for organic matter binding sites is still an open field of research; particularly, the mechanisms governing these phenomena need to be characterized in more detail. In this study, we examine spectroscopically the mechanisms of competitive binding of Eu(III)/Cu(II) and Eu(III)/Ca(II) pair to Gorleben humic acid (HA), as previously proposed in the framework of the NICA-Donnan model. The evolution of time-resolved laser induced luminescence spectra of humic-complexed Eu(Ill) showed two strikingly different environments for a comparable bound proportion for Cu(II) and Ca(II). Cu(II) seems to compete more effectively with Eu(III) inducing its release into the Donnan phase, and into the bulk solution as free Eu{sup 3+}. This is evidenced both by the shapes of the spectra and by the decrease in the luminescence decay times. In contrast with that, Ca(II) induces a modification of the HA structure, which enhances the luminescence of humic-bound Eu(III), and causes a minor modification of the chemical environment of the complexed rare earth ion. (authors)

  15. Physical conditions in CaFe interstellar clouds

    OpenAIRE

    Gnacinski, P.; Krogulec, M.

    2007-01-01

    Interstellar clouds that exhibit strong Ca I and Fe I lines were called CaFe clouds. The ionisation equilibrium equations were used to model the column densities of Ca II, Ca I, K I, Na I, Fe I and Ti II in CaFe clouds. The chemical composition of CaFe clouds is that of the Solar System and no depletion of elements onto dust grains is seen. The CaFe clouds have high electron densities n=1 cm^-3 that leads to high column densities of neutral Ca and Fe.

  16. Topological organization of CA3-to-CA1 excitation.

    Science.gov (United States)

    Hongo, Yoshie; Ogawa, Koichi; Takahara, Yuji; Takasu, Keiko; Royer, Sebastien; Hasegawa, Minoru; Sakaguchi, Gaku; Ikegaya, Yuji

    2015-09-01

    The CA1-projecting axons of CA3 pyramidal cells, called Schaffer collaterals, constitute one of the major information flow routes in the hippocampal formation. Recent anatomical studies have revealed the non-random structural connectivity between CA3 and CA1, but little is known regarding the functional connectivity (i.e. how CA3 network activity is functionally transmitted downstream to the CA1 network). Using functional multi-neuron calcium imaging of rat hippocampal slices, we monitored the spatiotemporal patterns of spontaneous CA3 and CA1 burst activity under pharmacological GABAergic blockade. We found that spatially clustered CA3 activity patterns were transformed into layered CA1 activity sequences. Specifically, synchronized bursts initiated from multiple hot spots in CA3 ensembles, and CA1 neurons located deeper in the pyramidal cell layer were recruited during earlier phases of the burst events. The order of these sequential activations was maintained across the bursts, but the sequence velocity varied depending on the inter-burst intervals. Thus, CA3 axons innervate CA1 neurons in a highly topographical fashion.

  17. Autonomous CaMKII requires further stimulation by Ca2+/calmodulin for enhancing synaptic strength.

    Science.gov (United States)

    Barcomb, Kelsey; Buard, Isabelle; Coultrap, Steven J; Kulbe, Jacqueline R; O'Leary, Heather; Benke, Timothy A; Bayer, K Ulrich

    2014-08-01

    A hallmark feature of Ca(2+)/calmodulin (CaM)-dependent protein kinase II (CaMKII) is generation of autonomous (Ca(2+)-independent) activity by T286 autophosphorylation. Biochemical studies have shown that "autonomous" CaMKII is ∼5-fold further stimulated by Ca(2+)/CaM, but demonstration of a physiological function for such regulation within cells has remained elusive. In this study, CaMKII-induced enhancement of synaptic strength in rat hippocampal neurons required both autonomous activity and further stimulation. Synaptic strength was decreased by CaMKIIα knockdown and rescued by reexpression, but not by mutants impaired for autonomy (T286A) or binding to NMDA-type glutamate receptor subunit 2B (GluN2B; formerly NR2B; I205K). Full rescue was seen with constitutively autonomous mutants (T286D), but only if they could be further stimulated (additional T305/306A mutation), and not with two other mutations that additionally impair Ca(2+)/CaM binding. Compared to rescue with wild-type CaMKII, the CaM-binding-impaired mutants even had reduced synaptic strength. One of these mutants (T305/306D) mimicked an inhibitory autophosphorylation of CaMKII, whereas the other one (Δstim) abolished CaM binding without introducing charged residues. Inhibitory T305/306 autophosphorylation also reduced GluN2B binding, but this effect was independent of reduced Ca(2+)/CaM binding and was not mimicked by T305/306D mutation. Thus, even autonomous CaMKII activity must be further stimulated by Ca(2+)/CaM for enhancement of synaptic strength.

  18. Scintillating CaWO{sub 4} crystals for the CRESST-II and EURECA dark matter searches

    Energy Technology Data Exchange (ETDEWEB)

    Sivers, Moritz v.; Ertl, Andreas; Guetlein, Achim; Lanfranchi, Jean-Come; Muenster, Andrea; Neumann, Felix; Potzel, Walter; Roth, Sabine; Schoenert, Stefan; Wawozcny, Stephan; Willers, Michael; Zoeller, Andreas [Physik Department, E15, Technische Universitaet Muenchen, 85748 Garching (Germany); Erb, Andreas [Walther-Meissner-Institut fuer Tieftemperatur Forschung, 85748 Garching (Germany); Strauss, Raimund; Wuestrich, Marc [Max-Planck-Institut fuer Physik, 80805 Muenchen (Germany)

    2014-07-01

    The CRESST-II experiment for the direct detection of WIMP dark matter uses scintillating CaWO{sub 4} crystals that are operated as low-temperature detectors. EURECA is a joint collaboration of existing cryogenic direct dark matter searches to develop a future multi-material experiment with a target mass of up to one ton. While in the past crystals were obtained from external suppliers, we recently started producing CaWO{sub 4} single crystals with a dedicated Czochralski furnace at the Technische Universitaet Muenchen to have a direct influence on the radiopurity and scintillation properties. We present here an overview of the growth process as well as measurements of the crystals' scintillation properties and radiopurity.

  19. Ca2+/calmodulin-dependent protein kinase II alpha is required for the initiation and maintenance of opioid-induced hyperalgesia.

    Science.gov (United States)

    Chen, Yan; Yang, Cheng; Wang, Zaijie Jim

    2010-01-01

    Repeated administration of opioids not only leads to tolerance and dependence, but also results in nociceptive enhancement called opioid-induced hyperalgesia (OIH). Nociceptive mediators involved in OIH generation remain poorly understood. In the present study, we tested the hypothesis that Ca(2+)/calmodulin-depent protein kinase II (CaMKIIalpha) is critical for OIH. Opioid-induced hyperalgesia was produced by repeated morphine administration or pellet implantation in mice. Correlating with the development of tactile allodynia and thermal hyperalgesia, spinal CaMKIIalpha activity was significantly increased in OIH. KN93, a CaMKII inhibitor, dose- and time-dependently reversed OIH and CaMKII activation without impairing locomotor coordination. To elucidate the specific CaMKII isoform involved, we targeted CaMKIIalpha by using small interfering RNA and demonstrated that knockdown of spinal CaMKIIalpha attenuated OIH. Furthermore, morphine failed to induce OIH in CaMKIIalpha(T286A) point mutant mice, although wild-type littermate mice developed robust OIH after repeated treatments with morphine. These data implicate, for the first time, an essential role of CaMKIIalpha as a cellular mechanism leading to and maintaining opioid-induced hyperalgesia.

  20. Electrodeposition of Ca Metal in CaCl2-CaO Molten Salt

    Institute of Scientific and Technical Information of China (English)

    GUO; Jun-kang; WANG; Chang-shui; CAO; Long-hao; OUYANG; Ying-gen

    2013-01-01

    To realize the continuouscalciothermic reduction in molten salts,the electrodeposition behavior of Ca metal in CaCl2-CaO molten salt was investigated by cylic voltammetry.The cyclic voltammograms at the scan rate of 100 mV/s are shown in Fig.1.As is shown,the electrodeposition potential of Ca deviated from-1.66 V to-0.97 V after CaO was added to molten CaCl2 and the decomposition of CaO

  1. Synthesis, Structural Characterization, and Antitumor Activity of a Ca(II Coordination Polymer Based on 1,6-Naphthalenedisulfonate and 4,4′-Bipyridyl

    Directory of Open Access Journals (Sweden)

    Xishi Tai

    2013-08-01

    Full Text Available A novel Ca(II coordination polymer, [CaL(4,4′-bipyridyl(H2O4]n (L = 1,6-naphthalenedisulfonate, was synthesized by reaction of calcium perchlorate with 1,6-naphthalenedisulfonic acid disodium salt and 4,4′-bipyridyl in CH3CH2OH/H2O. It was characterized by elemental analysis, IR, molar conductivity and thermogravimetric analysis. X-ray crystallography reveals that the Ca(II coordination polymer belongs to the orthorhombic system, with space group P212121. The geometry of the Ca(II ion is a distorted CaNO6 pengonal bipyramid, arising from its coordination by four water molecules, one nitrogen atom of 4,4′-bipyridyl molecule, and two oxygen atoms from two L ligands. The complex molecules form a helical chain by self-assembly. The antitumor activity of 1,6-naphthalenedisulfonic acid disodium salt and the Ca(II coordination polymer against human hepatoma smmc-7721 cell line and human lung adenocarcinoma A549 cell line reveals that the Ca(II coordination polymer inhibits cell growth of human lung adenocarcinoma A549 cell line with IC50 value of 27 μg/mL, and is more resistive to human lung adenocarcinoma A549 cell line as compared to 1,6-naphthalenedisulfonic acid disodium salt.

  2. Fine structure of the age-chromospheric activity relation in solar-type stars I: The Ca II infrared triplet: Absolute flux calibration

    CERN Document Server

    Lorenzo-Oliveira, Diego; Dutra-Ferreira, Letícia; Ribas, Ignasi

    2016-01-01

    Strong spectral lines are useful indicators of stellar chromospheric activity. They are physically linked to the convection efficiency, differential rotation, and angular momentum evolution and are a potential indicator of age. However, for ages > 2 Gyr, the age-activity relationship remains poorly constrained thus hampering its full application. The Ca II infrared triplet (IRT lines) has been poorly studied compared to classical chromospheric indicators. We report in this paper absolute chromospheric fluxes in the three Ca II IRT lines, based on a new calibration tied to up-to-date model atmospheres. We obtain the Ca II IRT absolute fluxes for 113 FGK stars from high signal-to-noise ratio and high-resolution spectra covering an extensive domain of chromospheric activity levels. We perform an absolute continuum flux calibration for the Ca II IRT lines anchored in atmospheric models calculated as an explicit function of effective temperatures, metallicity, and gravities avoiding the degeneracy present in photo...

  3. Synoptic and fast events on the sun according to observations at the center and wings of the Ca II K line at the Kislovodsk Mountain station patrol telescope

    Science.gov (United States)

    Tlatov, A. G.; Dormidontov, D. V.; Kirpichev, R. V.; Pashchenko, M. P.; Shramko, A. D.

    2015-12-01

    Observations performed at the solar telescope-spectroheliograph, which has continuously automatically operated at MAS MAO RAS, were analyzed. Measurements of the activity index in the Ca II K line, which were performed according to the program of synoptic observations, are presented. The development of the solar flares observed at the center and on the wings of the Ca II K line was compared with observations in the X-ray and radio bands. It was shown that the time variations in the intensity in the 1-8 Å range according to the Geostationary Orbiting Environmental Satellites' (GOES) data and in the Ca II K line are close to each other and that the total X-ray flux and Ca II K intensity amplitude substantially correlate during the entire flare.

  4. Mammalian Target of Rapamycin (mTOR) Tagging Promotes Dendritic Branch Variability through the Capture of Ca2+/Calmodulin-dependent Protein Kinase II α (CaMKIIα) mRNAs by the RNA-binding Protein HuD.

    Science.gov (United States)

    Sosanya, Natasha M; Cacheaux, Luisa P; Workman, Emily R; Niere, Farr; Perrone-Bizzozero, Nora I; Raab-Graham, Kimberly F

    2015-06-26

    The fate of a memory, whether stored or forgotten, is determined by the ability of an active or tagged synapse to undergo changes in synaptic efficacy requiring protein synthesis of plasticity-related proteins. A synapse can be tagged, but without the "capture" of plasticity-related proteins, it will not undergo long lasting forms of plasticity (synaptic tagging and capture hypothesis). What the "tag" is and how plasticity-related proteins are captured at tagged synapses are unknown. Ca(2+)/calmodulin-dependent protein kinase II α (CaMKIIα) is critical in learning and memory and is synthesized locally in neuronal dendrites. The mechanistic (mammalian) target of rapamycin (mTOR) is a protein kinase that increases CaMKIIα protein expression; however, the mechanism and site of dendritic expression are unknown. Herein, we show that mTOR activity mediates the branch-specific expression of CaMKIIα, favoring one secondary, daughter branch over the other in a single neuron. mTOR inhibition decreased the dendritic levels of CaMKIIα protein and mRNA by shortening its poly(A) tail. Overexpression of the RNA-stabilizing protein HuD increased CaMKIIα protein levels and preserved its selective expression in one daughter branch over the other when mTOR was inhibited. Unexpectedly, deleting the third RNA recognition motif of HuD, the domain that binds the poly(A) tail, eliminated the branch-specific expression of CaMKIIα when mTOR was active. These results provide a model for one molecular mechanism that may underlie the synaptic tagging and capture hypothesis where mTOR is the tag, preventing deadenylation of CaMKIIα mRNA, whereas HuD captures and promotes its expression in a branch-specific manner.

  5. Mammalian Target of Rapamycin (mTOR) Tagging Promotes Dendritic Branch Variability through the Capture of Ca2+/Calmodulin-dependent Protein Kinase II α (CaMKIIα) mRNAs by the RNA-binding Protein HuD*

    Science.gov (United States)

    Sosanya, Natasha M.; Cacheaux, Luisa P.; Workman, Emily R.; Niere, Farr; Perrone-Bizzozero, Nora I.; Raab-Graham, Kimberly F.

    2015-01-01

    The fate of a memory, whether stored or forgotten, is determined by the ability of an active or tagged synapse to undergo changes in synaptic efficacy requiring protein synthesis of plasticity-related proteins. A synapse can be tagged, but without the “capture” of plasticity-related proteins, it will not undergo long lasting forms of plasticity (synaptic tagging and capture hypothesis). What the “tag” is and how plasticity-related proteins are captured at tagged synapses are unknown. Ca2+/calmodulin-dependent protein kinase II α (CaMKIIα) is critical in learning and memory and is synthesized locally in neuronal dendrites. The mechanistic (mammalian) target of rapamycin (mTOR) is a protein kinase that increases CaMKIIα protein expression; however, the mechanism and site of dendritic expression are unknown. Herein, we show that mTOR activity mediates the branch-specific expression of CaMKIIα, favoring one secondary, daughter branch over the other in a single neuron. mTOR inhibition decreased the dendritic levels of CaMKIIα protein and mRNA by shortening its poly(A) tail. Overexpression of the RNA-stabilizing protein HuD increased CaMKIIα protein levels and preserved its selective expression in one daughter branch over the other when mTOR was inhibited. Unexpectedly, deleting the third RNA recognition motif of HuD, the domain that binds the poly(A) tail, eliminated the branch-specific expression of CaMKIIα when mTOR was active. These results provide a model for one molecular mechanism that may underlie the synaptic tagging and capture hypothesis where mTOR is the tag, preventing deadenylation of CaMKIIα mRNA, whereas HuD captures and promotes its expression in a branch-specific manner. PMID:25944900

  6. Effect of lipid matrix and cytoskeleton proteins on Ca2+-activated K+ channels in erythrocytes of alcoholic and II type diabetes mellitus patients.

    Science.gov (United States)

    Prokop'eva, V D; Petrova, I V; Sitozhevskii, A V; Kremeno, S V; Koryukin, V I; Baskakov, M B; Bokhan, N A; Novitskii, V V

    2002-10-01

    We studied the effect of changes in erythrocyte volume and irreversible thermal denaturation of cytoskeleton proteins and lipid matrix on activity of Ca(2+)-activated K+ channels in erythrocytes of alcoholic and patients with II type diabetes mellitus. Changes in Ca(2+)-dependent potassium permeability of erythrocyte membrane in alcoholic patients and patients with II type diabetes mellitus are related to modification of cytoskeleton, rather than to changes in lipid matrix.

  7. Desorption of Hg(II) and Sb(V) on extracellular polymeric substances: effects of pH, EDTA, Ca(II) and temperature shocks.

    Science.gov (United States)

    Zhang, Daoyong; Lee, Duu-Jong; Pan, Xiangliang

    2013-01-01

    Extracellular polymeric substances (EPS) existed ubiquitously in biological systems affect the mobility and availability of heavy metals in the environments. The adsorption-desorption behaviors of Hg(II) and Sb(V) on EPS were investigated. The sorption rates follow Sb(V) > Hg(II), and the desorption rates follow reverse order. Applications of ethylene diamine tetraacetic acid (EDTA), Ca(II) and pH shocks affect desorption rates and desorbed quantities of Hg(II) from EPS-Hg complex. Temperature shock minimally affects the desorption rate of Hg(II). Conversely, the EPS-Sb complex is stable subjected to EDTA, Ca(II), temperature or pH shocks. The excitation-emission matrix (EEM) fluorescence spectroscopy and fast-Fourier (FT-IR) analysis showed that Hg(II) and Sb(V) principally interacted with polysaccharides and protein-like compounds in the EPS, respectively. The EPS-Hg complex presents a time bomb that may release high levels of Hg(II) in short time period under environmental shocks.

  8. Sulfide capacities of CaO-CaF2-CaCl2 melts

    Science.gov (United States)

    Simeonov, Simeon; Sakai, Toshihiko; Maeda, Masafumi

    1992-06-01

    The sulfide capacityC_{s^{2 - } } = ({text{pct S}}^{{text{2 - }}} )(p_{{text{O}}_{text{2}} } /p_{{text{S}}_{text{2}} } )^{1/2} ) of CaO-CaF2-CaCl2 slag was determined at temperatures from 1000 °C to 1300 °C by equilibrating molten slag, molten silver, and CO-CO2-Ar gas mixture. The sulfide capacity increases with replacing CaCl2 by CaF2 in slags of constant CaO contents. The sulfide capacity also increases with increasing temperature as well as with increasing CaO content at a constant ratio of CaF2/CaCl2 of unity. A linear relationship between the sulfide capacity and carbonate capacity in literature was observed on a logarithmic scale.

  9. Kinetic and thermodynamic studies of the Co(II) and Ni(II) ions removal from aqueous solutions by Ca-Mg phosphates.

    Science.gov (United States)

    Ivanets, A I; Srivastava, V; Kitikova, N V; Shashkova, I L; Sillanpää, M

    2017-03-01

    The aim of this work was to study the sorption kinetics and thermodynamics of Co(II) and Ni(II) from aqueous solutions by sorbents on the basis of hydrogen (PD-1) and tertiary (PD-2) Ca-Mg phosphates depending on the solution temperature and sorbents chemical composition. Kinetic studies of adsorption of Co(II) and Ni(II) ions onto samples of phosphate sorbents were performed in batch experiment at the temperatures 288, 303, 318 and 333 K. The sorbent dose was fixed at 10 g L(-1), initial pH value 2.6, and contact time varied from 5 to 600 min. The kinetics of Co(II) and Ni(II) adsorption were analyzed by using pseudo-first order, pseudo-second order and intraparticle diffusion models. Thermodynamic parameters (ΔG°, ΔH° and ΔS°) for the sorption of Co(II) and Ni(II) were determined using the Gibbs-Helmholtz equation. The calculated kinetic parameters and corresponding correlation coefficients revealed that Co(II) and Ni(II) uptake process followed the pseudo-second order rate expression. Thermodynamic studies confirmed the spontaneous and endothermic nature of removal process which indicate that sorption of Co(II) and Ni(II) ions onto both phosphate sorbents is favoured at higher temperatures and has the chemisorptive mechanism. The data thus obtained would be useful for practical application of the low cost and highly effective Ca-Mg phosphate sorbents.

  10. Unveiling Vela - Time Variability of Interstellar Lines in the Direction of the Vela Supernova Remnant II. Na D and Ca II

    Science.gov (United States)

    Kameswara Rao, N.; Lambert, David L.; Reddy, Arumalla B. S.; Gupta, Ranjan; Muneer, S.; Singh, Harinder P.

    2017-01-01

    In a survey conducted between 2011-12 of interstellar Na I D line profiles in the direction of the Vela supernova remnant, a few lines of sight showed dramatic changes in low velocity absorption components with respect to profiles from 1993-1994 reported by Cha & Sembach. Three stars - HD 63578, HD 68217 and HD 76161 showed large decrease in strength over the 1993-2012 interval. HD 68217 and HD 76161 are associated with the Vela SNR whereas HD 63578 is associated with γ2 Velorum wind bubble. Here, we present high spectral resolution observations of Ca II K lines obtained with the Southern African Large Telescope (SALT) towards these three stars along with simultaneous observations of Na I D lines. These new spectra confirm that the Na D interstellar absorption weakened drastically between 1993-1994 and 2011-2012 but show for the first time that the Ca II K line is unchanged between 1993-1994 and 2015. This remarkable contrast between the behaviour of Na D and Ca II K line absorption lines is a puzzle concerning gas presumably affected by the outflow from the SNR and the wind from γ2 Velorum.

  11. APE1/Ref-1 promotes the effect of angiotensin II on Ca2+ -activated K+ channel in human endothelial cells via suppression of NADPH oxidase.

    Science.gov (United States)

    Park, Won Sun; Ko, Eun A; Jung, In Duk; Son, Youn Kyoung; Kim, Hyoung Kyu; Kim, Nari; Park, So Youn; Hong, Ki Whan; Park, Yeong-Min; Choi, Tae-Hoon; Han, Jin

    2008-10-01

    The effects of angiotensin II (Ang II) on whole-cell large conductance Ca(2+)-activated K(+) (BK(Ca)) currents was investigated in control and Apurinic/apyrimidinic endonuclease1/redox factor 1 (APE1/Ref-1)-overexpressing human umbilical vein endothelial cells (HUVECs). Ang II blocked the BK(Ca) current in a dose-dependent fashion, and this inhibition was greater in APE1/Ref-1-overexpressing HUVECs than in control HUVECs (half-inhibition values of 102.81+/-9.54 nM and 11.34+/-0.39 nM in control and APE1/Ref-1-overexpressing HUVECs, respectively). Pretreatment with the NADPH oxidase inhibitor diphenyleneiodonium (DPI) or knock down of NADPH oxidase (p22 phox) using siRNA increased the inhibitory effect of Ang II on the BK(Ca) currents, similar to the effect of APE1/Ref-1 overexpression. In addition, application of Ang II increased the superoxide and hydrogen peroxide levels in the control HUVECs but not in APE1/Ref-1-overexpressing HUVECs. Furthermore, direct application of hydrogen peroxide increased BK(Ca) channel activity. Finally, the inhibitory effect of Ang II on the BK(Ca) current was blocked by an antagonist of the Ang II type 1 (AT(1)) receptor in both control and APE1/Ref-1-overexpressing HUVECs. From these results, we conclude that the inhibitory effect of Ang II on BK(Ca) channel function is NADPH oxidase-dependent and may be promoted by APE1/Ref-1.

  12. Spectroscopic (FT-IR, FT-Raman, 1H, 13C NMR, UV/VIS), thermogravimetric and antimicrobial studies of Ca(II), Mn(II), Cu(II), Zn(II) and Cd(II) complexes of ferulic acid

    Science.gov (United States)

    Kalinowska, M.; Piekut, J.; Bruss, A.; Follet, C.; Sienkiewicz-Gromiuk, J.; Świsłocka, R.; Rzączyńska, Z.; Lewandowski, W.

    2014-03-01

    The molecular structure of Mn(II), Cu(II), Zn(II), Cd(II) and Ca(II) ferulates (4-hydroxy-3-methoxycinnamates) was studied. The selected metal ferulates were synthesized. Their composition was established by means of elementary and thermogravimetric analysis. The following spectroscopic methods were used: infrared (FT-IR), Raman (FT-Raman), nuclear magnetic resonance (13C, 1H NMR) and ultraviolet-visible (UV/VIS). On the basis of obtained results the electronic charge distribution in studied metal complexes in comparison with ferulic acid molecule was discussed. The microbiological study of ferulic acid and ferulates toward Escherichia coli, Bacillus subtilis, Candida albicans, Pseudomonas aeruginosa, Staphylococcus aureus and Proteus vulgaris was done.

  13. Using the Ca II Triplet to Trace Abundance Variations in Individual Red Giant Branch stars in Three Nearby Galaxies

    CERN Document Server

    Tolstoy, E; Cole, A A; Pasquini, L; Gilmozzi, R; Gallagher, J S; Tolstoy, Eline; Irwin, Michael J.; Cole, Andrew A.

    2001-01-01

    Spectroscopic abundance determinations for stars spanning a Hubble time in age are necessary in order to unambiguously determine the evolutionary histories of galaxies. Using FORS1 in Multi-Object Spectroscopy mode on ANTU (UT1) at the ESO-VLT on Paranal we obtained near infrared spectra from which we measured the equivalent widths of the two strongest Ca II triplet lines to determine metal abundances for a sample of Red Giant Branch stars, selected from ESO-NTT optical (I, V-I) photometry of three nearby, Local Group, galaxies: the Sculptor Dwarf Spheroidal, the Fornax Dwarf Spheroidal and the Dwarf Irregular NGC 6822. The summed equivalent width of the two strongest lines in the Ca II triplet absorption line feature, centered at 8500A, can be readily converted into an [Fe/H] abundance using the previously established calibrations by Armandroff & Da Costa (1991) and Rutledge, Hesser & Stetson (1997). We measured metallicities for 37 stars in Sculptor, 32 stars in Fornax, and 23 stars in NGC 6822, yie...

  14. The effect of isotopic splitting on the bisector and inversions of the solar Ca II 854.2 nm line

    CERN Document Server

    Leenaarts, Jorrit; Kochukhov, Oleg; Carlsson, Mats

    2014-01-01

    The Ca II 854.2 nm spectral line is a common diagnostic of the solar chromosphere. The average line profile shows an asymmetric core, and its bisector shows a characteristic inverse-C shape. The line actually consists of six components with slightly different wavelengths depending on the isotope of calcium. This isotopic splitting of the line has been taken into account in studies of non-solar stars, but never for the Sun. We performed non-LTE radiative transfer computations from three models of the solar atmosphere and show that the asymmetric line-core and inverse C-shape of the bisector of the 854.2 nm line can be explained by isotopic splitting. We confirm this finding by analysing observations and showing that the line asymmetry is present irrespective of conditions in the solar atmosphere. Finally, we show that inversions based on the Ca II 854.2 nm line should take the isotopic splitting into account, otherwise the inferred atmospheres will contain erroneous velocity gradients and temperatures.

  15. Angiotensin II increases nerve-evoked contractions in mouse tail artery by a T-type Ca(2+) channel-dependent mechanism.

    Science.gov (United States)

    Reardon, Trent F; Callaghan, Brid P; Brock, James A

    2015-08-15

    Angiotensin II (Ang II) increases sympathetic nerve-evoked contractions of arterial vessels. Here the mechanisms underlying this effect were investigated in mouse tail artery. Isometrically mounted segments of mouse distal tail artery were used to investigate the effects of endothelium denudation, blocking Ca(2+) channels and inhibiting superoxide signalling on Ang II-induced facilitation of nerve-evoked contractions. In addition, in situ amperometry was used to assess effects of Ang II on noradrenaline release. Ang II (0.1-1nM) increased nerve-evoked contractions but did not change noradrenaline release. Losartan (Ang II type 1 receptor antagonist), but not PD 123319 (Ang II type 2 receptor antagonist), blocked the facilitatory effect of Ang II on nerve-evoked contractions. Ang II increased vascular muscle reactivity to phenylephrine and UK-14304 (α1- and α2-adrenoceptor agonists, respectively). Endothelial denudation increased nerve-evoked contractions and reduced the facilitatory effect of Ang II on these responses. Efonidipine (L- and T-type Ca(2+) channel blocker) and NNC 55-0396 (T-type Ca(2+) channel blocker) also attenuated this effect of Ang II, while nifedipine (L-type Ca(2+) channel blocker) did not. Blockers of superoxide generation/signalling did not change the facilitatory effect of Ang II on nerve-evoked contractions. The findings indicate that Ang II increases the contribution of T-type Ca(2+) channels to neural activation of the vascular muscle. In addition, Ang II appears to reduce the inhibitory influence of the endothelium on nerve-evoked contractions.

  16. CaMKII inhibition targeted to the sarcoplasmic reticulum inhibits frequency dependent acceleration of relaxation and Ca2+ current facilitation

    OpenAIRE

    Picht, Eckard; DeSantiago, Jaime; Huke, Sabine; Kaetzel, Marcia A.; Dedman, John R.; Bers, Donald M.

    2006-01-01

    Cardiac Ca2+/calmodulin-dependent protein kinase II (CaMKII) in heart has been implicated in Ca2+ current (ICa) facilitation, enhanced sarcoplasmic reticulum (SR) Ca2+ release and frequency dependent acceleration of relaxation (FDAR) via enhanced SR Ca2+ uptake. However, questions remain about how CaMKII may work in these three processes. Here we tested the role of CaM-KII in these processes using transgenic mice (SR-AIP) that express four concatenated repeats of the CaMKII inhibitory peptide...

  17. Ca(II, Zn(II and Au(III sulfamethoxazole sulfa-drug complexes: Synthesis, spectroscopic and anticancer evaluation studies

    Directory of Open Access Journals (Sweden)

    Fatima A.I. Al-Khodir

    2015-09-01

    Full Text Available Herein in this article, three new Ca(II, Zn(II and Au(III complexes of sulfamethoxazole (SZ (sulfa-drug have been synthesized for the first time. The sulfa-drugs have a great attentions because of their therapeutic applications against bacterial infections. The SZ complexes were discussed with the help of elemental analyses, molar conductance and spectroscopic instruments e.g. IR, 1H-NMR, and electronic spectra. Investigations of the infrared spectra of the SZ and their metal complexes indicated the vibrations due to the sulfonamido (SO2 and –NH and isoxazole (C=N groups are shifted with respect to the free molecule in line with their coordination to the metal. In case of calcium(II an zinc(II complexes, the coordination site of SZ are the sulfonyl oxygen and SO2-NH sulfonamide nitrogen, but in gold(III complex, the gold metal ions coordinates through the sulfonyl oxygen and isoxazole nitrogen. These complexes are formulated as: [Ca(SZ(Cl2].8H2O (1, [Zn(SZ(Cl2].2H2O (2 and [Au(SZ(Cl2].Cl (3. The molar conductance data reveals that both Ca(II and Zn(II complexes are non-electrolyte but gold(III complex is electrolyte. The morphological nano structures of SZ complexes were checked using X-ray powder diffraction (XRD, scanning electron microscope (SEM and transmission electron microscopy (TEM. The gold(III complex was recorded good anticancer behavior against Human colon carcinoma (HCT-116 cells and human hepatocellular carcinoma (HepG-2 cells.

  18. Mechanochemical synthesis and intercalation of Ca(II)Fe(III)-layered double hydroxides

    Science.gov (United States)

    Ferencz, Zs.; Szabados, M.; Varga, G.; Csendes, Z.; Kukovecz, Á.; Kónya, Z.; Carlson, S.; Sipos, P.; Pálinkó, I.

    2016-01-01

    A mechanochemical method (grinding the components without added water - dry grinding, followed by further grinding in the presence of minute amount of water or NaOH solution - wet grinding) was used in this work for the preparation and intercalation of CaFe-layered double hydroxides (LDHs). Both the pristine LDHs and the amino acid anion (cystinate and tyrosinate) intercalated varieties were prepared by the two-step grinding procedure in a mixer mill. By systematically changing the conditions of the preparation method, a set of parameters could be determined, which led to the formation of close to phase-pure LDH. The optimisation procedure was also applied for the intercalation processes of the amino acid anions. The resulting materials were structurally characterised by a range of methods (X-ray diffractometry, scanning electron microscopy, energy dispersive analysis, thermogravimetry, X-ray absorption and infra-red spectroscopies). It was proven that this simple mechanochemical procedure was able to produce complex organic-inorganic nanocomposites: LDHs intercalated with amino acid anions.

  19. The large- and small-scale CaII K structure of the Milky Way from observations of Galactic and Magellanic sightlines

    CERN Document Server

    Smoker, J V; Fox, A J

    2015-01-01

    Aims: By utilising spectra of early-type stellar probes of known distances in the same region of the sky, the large and small-scale (pc) structure of the Galactic ISM can be investigated. This paper determines the variation in line strength of CaII at 3933.661 A, as a function of probe separation for a sample of stars, including many sightlines in the Magellanic Clouds. Methods: FLAMES-GIRAFFE data taken with the VLT towards early-type stars in 3 Galactic & 4 Magellanic open clusters in CaII are used to obtain the velocity, EW, column density and line width of IS Galactic Ca for a total of 657 stars, of which 443 are Magellanic sightlines. In each cluster there are 43-110 stars observed. Additionally, FEROS and UVES CaII & NaI spectra of 21 Galactic & 154 Magellanic early-type stars are presented and combined with data from the literature to study the Ca column density/parallax relationship. Results: For the four Magellanic clusters studied with FLAMES, the strength of the Galactic IS CaII K EW ov...

  20. Age-dependent targeting of protein phosphatase 1 to Ca2+/calmodulin-dependent protein kinase II by spinophilin in mouse striatum.

    Directory of Open Access Journals (Sweden)

    Anthony J Baucum

    Full Text Available Mechanisms underlying age-dependent changes of dendritic spines on striatal medium spiny neurons are poorly understood. Spinophilin is an F-actin- and protein phosphatase 1 (PP1-binding protein that targets PP1 to multiple downstream effectors to modulate dendritic spine morphology and function. We found that calcium/calmodulin-dependent protein kinase II (CaMKII directly and indirectly associates with N- and C-terminal domains of spinophilin, but F-actin can displace CaMKII from the N-terminal domain. Spinophilin co-localizes PP1 with CaMKII on the F-actin cytoskeleton in heterologous cells, and spinophilin co-localizes with synaptic CaMKII in neuronal cultures. Thr286 autophosphorylation enhances the binding of CaMKII to spinophilin in vitro and in vivo. Although there is no change in total levels of Thr286 autophosphorylation, maturation from postnatal day 21 into adulthood robustly enhances the levels of CaMKII that co-immunoprecipitate with spinophilin from mouse striatal extracts. Moreover, N- and C-terminal domain fragments of spinophilin bind more CaMKII from adult vs. postnatal day 21 striatal lysates. Total levels of other proteins that interact with C-terminal domains of spinophilin decrease during maturation, perhaps reducing competition for CaMKII binding to the C-terminal domain. In contrast, total levels of α-internexin and binding of α-internexin to the spinophilin N-terminal domain increases with maturation, perhaps bridging an indirect interaction with CaMKII. Moreover, there is an increase in the levels of myosin Va, α-internexin, spinophilin, and PP1 in striatal CaMKII immune complexes isolated from adult and aged mice compared to those from postnatal day 21. These changes in spinophilin/CaMKII interactomes may contribute to changes in striatal dendritic spine density, morphology, and function during normal postnatal maturation and aging.

  1. Membrane actions of 1α,25(OH)2D3 are mediated by Ca(2+)/calmodulin-dependent protein kinase II in bone and cartilage cells.

    Science.gov (United States)

    Doroudi, Maryam; Plaisance, Marc C; Boyan, Barbara D; Schwartz, Zvi

    2015-01-01

    1α,25(OH)2D3 regulates osteoblasts and chondrocytes via its membrane-associated receptor, protein disulfide isomerase A3 (Pdia3) in caveolae. 1α,25(OH)2D3 binding to Pdia3 leads to phospholipase-A2 (PLA2)-activating protein (PLAA) activation, stimulating cytosolic PLA2 and resulting in prostaglandin E2 (PGE2) release and PKCα activation, subsequently stimulating differentiation. However, how PLAA transmits the signal to cPLA2 is unknown. Ca(2+)/calmodulin (CaM)-dependent protein kinase II (CaMKII) activation is required for PLA2 activation in vascular smooth muscle cells, suggesting a similar role in 1α,25(OH)2D3-dependent signaling. The aim of the present study is to evaluate the roles of CaM and CaMKII as mediators of 1α,25(OH)2D3-stimulated PLAA-dependent activation of cPLA2 and PKCα, and downstream biological effects. The results indicated that 1α,25(OH)2D3 and PLAA-peptide increased CaMKII activity within 9 min. Silencing Cav-1, Pdia3 or Plaa in osteoblasts suppressed this effect. Similarly, antibodies against Plaa or Pdia3 blocked 1α,25(OH)2D3-dependent CaMKII. Caveolae disruption abolished activation of CaMKII by 1α,25(OH)2D3 or PLAA. CaMKII-specific and CaM-specific inhibitors reduced cPLA2 and PKC activities, PGE2 release and osteoblast maturation markers in response to 1α,25(OH)2D3. Camk2a-silenced but not Camk2b-silenced osteoblasts showed comparable effects. Immunoprecipitation showed increased interaction of CaM and PLAA in response to 1α,25(OH)2D3. The results indicate that membrane actions of 1α,25(OH)2D3 via Pdia3 triggered the interaction between PLAA and CaM, leading to dissociation of CaM from caveolae, activation of CaMKII, and downstream PLA2 activation, and suggest that CaMKII plays a major role in membrane-mediated actions of 1α,25(OH)2D3.

  2. Phosphorylation of the PCNA binding domain of the large subunit of replication factor C by Ca2+/calmodulin-dependent protein kinase II inhibits DNA synthesis

    DEFF Research Database (Denmark)

    Maga, G; Mossi, R; Fischer, R

    1997-01-01

    that the PCNA binding domain is phosphorylated by the Ca2+/calmodulin-dependent protein kinase II (CaMKII), an enzyme required for cell cycle progression in eukaryotic cells. The DNA binding domain, on the other hand, is not phosphorylated. Phosphorylation by CaMKII reduces the binding of PCNA to RF......Replication factor C (RF-C) is a heteropentameric protein essential for DNA replication and DNA repair. It is a molecular matchmaker required for loading of the proliferating cell nuclear antigen (PCNA) sliding clamp onto double-strand DNA and for PCNA-dependent DNA synthesis by DNA polymerases...

  3. Ca II Triplet Spectroscopy of Small Magellanic Cloud Red Giants. III. Abundances and Velocities for a Sample of 14 Clusters

    CERN Document Server

    Parisi, M C; Clariá, J J; Villanova, S; Marcionni, N; Sarajedini, A; Grocholski, A J

    2015-01-01

    We obtained spectra of red giants in 15 Small Magellanic Cloud (SMC) clusters in the region of the CaII lines with FORS2 on the Very Large Telescope (VLT). We determined the mean metallicity and radial velocity with mean errors of 0.05 dex and 2.6 km/s, respectively, from a mean of 6.5 members per cluster. One cluster (B113) was too young for a reliable metallicity determination and was excluded from the sample. We combined the sample studied here with 15 clusters previously studied by us using the same technique, and with 7 clusters whose metallicities determined by other authors are on a scale similar to ours. This compilation of 36 clusters is the largest SMC cluster sample currently available with accurate and homogeneously determined metallicities. We found a high probability that the metallicity distribution is bimodal, with potential peaks at -1.1 and -0.8 dex. Our data show no strong evidence of a metallicity gradient in the SMC clusters, somewhat at odds with recent evidence from CaT spectra of a lar...

  4. Simulations of the Mg II k and Ca II 8542 lines from an AlfvÉn Wave-heated Flare Chromosphere

    Science.gov (United States)

    Kerr, Graham S.; Fletcher, Lyndsay.; Russell, Alexander J. B.; Allred, Joel C.

    2016-08-01

    We use radiation hydrodynamic simulations to examine two models of solar flare chromospheric heating: Alfvén wave dissipation and electron beam collisional losses. Both mechanisms are capable of strong chromospheric heating, and we show that the distinctive atmospheric evolution in the mid-to-upper chromosphere results in Mg ii k-line emission that should be observably different between wave-heated and beam-heated simulations. We also present Ca ii 8542 Å profiles that are formed slightly deeper in the chromosphere. The Mg ii k-line profiles from our wave-heated simulation are quite different from those from a beam-heated model and are more consistent with Interface Region Imaging Spectrograph observations. The predicted differences between the Ca ii 8542 Å in the two models are small. We conclude that careful observational and theoretical study of lines formed in the mid-to-upper chromosphere holds genuine promise for distinguishing between competing models for chromospheric heating in flares.

  5. Efficient biosorption of lead(II) and cadmium(II) ions from aqueous solutions by functionalized cell with intracellular CaCO3 mineral scaffolds.

    Science.gov (United States)

    Ma, Xiaoming; Cui, Weigang; Yang, Lin; Yang, Yuanyuan; Chen, Huifeng; Wang, Kui

    2015-06-01

    The functionalized Saccharomyces cerevisiae cell with biogenic intracellular CaCO3 mineral scaffold, synthesized via a simple and environmentally friendly approach, was efficient for removing lead (II) and cadmium (II) ions from aqueous solutions. The CaCO3 mineral scaffold could promote the uptake of the heavy metal ions and increase the biosorption capabilities of the adsorbent. Compared with the Freundlich isotherm, Langmuir model more fitted the equilibrium data. The maximum removal capacity of functionalized cells for Pb(II) and Cd(II) was 116.69 and 42.63mgg(-1), respectively. Further investigation showed that the adsorbent had high removal efficiency for trace amount of heavy metal ions. Adsorption data were modeled using the pseudo-first-order, pseudo-second-order and intra-particle diffusion kinetics equations. The results indicated that pseudo-second-order kinetic equation and intra-particle diffusion model could better describe the adsorption kinetics. The heavy metal ions might be removed by functionalized cells via membrane transport of metal ions and precipitation transformation.

  6. Synthesis, spectroscopic, thermal and anticancer studies of metal-antibiotic chelations: Ca(II), Fe(III), Pd(II) and Au(III) chloramphenicol complexes

    Science.gov (United States)

    Al-Khodir, Fatima A. I.; Refat, Moamen S.

    2016-09-01

    Four Ca(II), Fe(III), Pd(II) and Au(III) complexes of chloramphenicol drug have been synthesized and well characterized using elemental analyses, (infrared, electronic, and 1H-NMR) spectra, magnetic susceptibility measurement, and thermal analyses. Infrared spectral data show that the chloramphenicol drug coordinated to Ca(II), Pd(II) and Au(III) metal ions through two hydroxyl groups with 1:1 or 1:2 M ratios, but Fe(III) ions chelated towards chloramphenicol drug via the oxygen and nitrogen atoms of amide group with 1:2 ratio based on presence of keto↔enol form. The X-ray powder diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM) techniques were used to identify the nano-size particles of both iron(III) and gold(III) chloramphenicol complexes. The antimicrobial assessments of the chloramphenicol complexes were scanned and collected the results against of some kind of bacteria and fungi. The cytotoxic activity of the gold(III) complex was tested against the human colon carcinoma (HCT-116) and human hepatocellular carcinoma (HepG-2) tumor cell lines.

  7. Gentamicin Blocks the ACh-Induced BK Current in Guinea Pig Type II Vestibular Hair Cells by Competing with Ca2+ at the l-Type Calcium Channel

    Directory of Open Access Journals (Sweden)

    Hong Yu

    2014-04-01

    Full Text Available Type II vestibular hair cells (VHCs II contain big-conductance Ca2+-dependent K+ channels (BK and L-type calcium channels. Our previous studies in guinea pig VHCs II indicated that acetylcholine (ACh evoked the BK current by triggering the influx of Ca2+ ions through l-type Ca2+ channels, which was mediated by M2 muscarinic ACh receptor (mAChRs. Aminoglycoside antibiotics, such as gentamicin (GM, are known to have vestibulotoxicity, including damaging effects on the efferent nerve endings on VHCs II. This study used the whole-cell patch clamp technique to determine whether GM affects the vestibular efferent system at postsynaptic M2-mAChRs or the membrane ion channels. We found that GM could block the ACh-induced BK current and that inhibition was reversible, voltage-independent, and dose-dependent with an IC50 value of 36.3 ± 7.8 µM. Increasing the ACh concentration had little influence on GM blocking effect, but increasing the extracellular Ca2+ concentration ([Ca2+]o could antagonize it. Moreover, 50 µM GM potently blocked Ca2+ currents activated by (--Bay-K8644, but did not block BK currents induced by NS1619. These observations indicate that GM most likely blocks the M2 mAChR-mediated response by competing with Ca2+ at the l-type calcium channel. These results provide insights into the vestibulotoxicity of aminoglycoside antibiotics on mammalian VHCs II.

  8. Intracellular angiotensin II elicits Ca2+ increases in A7r5 vascular smooth muscle cells

    NARCIS (Netherlands)

    Filipeanu, CM; Brailoiu, E; Kok, JW; Henning, RH; De Zeeuw, D; Nelemans, SA

    2001-01-01

    Recent studies show that angiotensin II can act within the cell, possibly via intracellular receptors pharmacologically different from typical plasma membrane angiotensin II receptors. The signal transduction of intracellular angiotensin LI is unclear. Therefore. we investigated the effects of intra

  9. Probing Our Heliospheric History I: High-Resolution Observations of Na I and Ca II Along the Solar Historical Trajectory

    CERN Document Server

    Wyman, Katherine

    2013-01-01

    Over the course of its motion through the Galaxy, our solar system has encountered many interstellar environments of varying characteristics. Interstellar medium (ISM) density variations spanning seven orders of magnitude are commonly seen throughout the general Galactic environment, and a sufficiently dense cloud within this range has the potential to dramatically alter the structure of the heliosphere. We present observations of the ISM environments the Sun has most recently encountered based on high-resolution optical spectra toward nearby stars in the direction of the historical solar trajectory. The data were obtained with the highest-resolution spectrographs available, including the Tull Spectrograph on the Harlan J. Smith Telescope at McDonald Observatory and the Ultra-High-Resolution Facility on the Anglo-Australian Telescope at the Anglo-Australian Observatory. Observations were made of interstellar Na I and Ca II doublet absorption toward 43 bright stars within about 500 pc. No absorption is seen ou...

  10. Ca(ii) and Ce(iii) homogeneous alginate hydrogels from the parent alginic acid precursor: a structural study.

    Science.gov (United States)

    Sonego, Juan Manuel; Santagapita, Patricio R; Perullini, Mercedes; Jobbágy, Matías

    2016-06-14

    Alginate hydrogels are suitable for the encapsulation of biomolecules and microorganisms for the building of bioactive materials. Several alternatives to the conventional alginate formulation are being studied for a broad range of biotechnological applications; among them the crosslinking of alginate by lanthanide cations, Ln(iii), envisages expanded biomedical applications. The performance of these functional materials is highly related to the microstructure of the alginate matrix, which in turn is affected by the conditions of synthesis. In particular, when a diffusing gradient of the crosslinking cation is involved, microstructure inhomogeneities are expected at the macroscopic level. Here we discuss the subtle differences in the microstructure, as assessed by SAXS (Small Angle X-ray Scattering), established in the direction of the gradient of diffusion of Ca(ii) or Ce(iii).

  11. Investigation of Neuronal Cell Type-Specific Gene Expression of Ca2+/Calmodulin-dependent Protein Kinase II.

    Directory of Open Access Journals (Sweden)

    Mima Kazuko

    2002-01-01

    Full Text Available The promoter activity of the rat Ca2+/calmodulin-dependent protein kinase II gene was analyzed using the luciferase reporter gene in neuronal and non-neuronal cell lines. Neuronal cell type-specific promoter activity was found in the 5'-flanking region of &agr; and &bgr; isoform genes of the kinase. Silencer elements were also found further upstream of promoter regions. A brain-specific protein bound to the DNA sequence of the 5'-flanking region of the gene was found by gel mobility shift analysis in the nuclear extract of the rat brain, including the cerebellum, forebrain, and brainstem, but not in that of non-neuronal tissues, including liver, kidney and spleen. The luciferase expression system and gel shift analysis can be used as an additional and better index by which to monitor gene expression in most cell types.

  12. CA II TRIPLET SPECTROSCOPY OF SMALL MAGELLANIC CLOUD RED GIANTS. III. ABUNDANCES AND VELOCITIES FOR A SAMPLE OF 14 CLUSTERS

    Energy Technology Data Exchange (ETDEWEB)

    Parisi, M. C.; Clariá, J. J.; Marcionni, N. [Observatorio Astronómico, Universidad Nacional de Córdoba, Laprida 854, Córdoba, CP 5000 (Argentina); Geisler, D.; Villanova, S. [Departamento de Astronomía, Universidad de Concepción Casilla 160-C, Concepción (Chile); Sarajedini, A. [Department of Astronomy, University of Florida P.O. Box 112055, Gainesville, FL 32611 (United States); Grocholski, A. J., E-mail: celeste@oac.uncor.edu, E-mail: claria@oac.uncor.edu, E-mail: nmarcionni@oac.uncor.edu, E-mail: dgeisler@astro-udec.cl, E-mail: svillanova@astro-udec.cl, E-mail: ata@astro.ufl.edu, E-mail: grocholski@phys.lsu.edu [Department of Physics and Astronomy, Louisiana State University 202 Nicholson Hall, Tower Drive, Baton Rouge, LA 70803-4001 (United States)

    2015-05-15

    We obtained spectra of red giants in 15 Small Magellanic Cloud (SMC) clusters in the region of the Ca ii lines with FORS2 on the Very Large Telescope. We determined the mean metallicity and radial velocity with mean errors of 0.05 dex and 2.6 km s{sup −1}, respectively, from a mean of 6.5 members per cluster. One cluster (B113) was too young for a reliable metallicity determination and was excluded from the sample. We combined the sample studied here with 15 clusters previously studied by us using the same technique, and with 7 clusters whose metallicities determined by other authors are on a scale similar to ours. This compilation of 36 clusters is the largest SMC cluster sample currently available with accurate and homogeneously determined metallicities. We found a high probability that the metallicity distribution is bimodal, with potential peaks at −1.1 and −0.8 dex. Our data show no strong evidence of a metallicity gradient in the SMC clusters, somewhat at odds with recent evidence from Ca ii triplet spectra of a large sample of field stars. This may be revealing possible differences in the chemical history of clusters and field stars. Our clusters show a significant dispersion of metallicities, whatever age is considered, which could be reflecting the lack of a unique age–metallicity relation in this galaxy. None of the chemical evolution models currently available in the literature satisfactorily represents the global chemical enrichment processes of SMC clusters.

  13. Synthesis, spectroscopic and thermal studies of Mg(II), Ca(II), Sr(II) and Ba(II) diclofenac sodium complexes as anti-inflammatory drug and their protective effects on renal functions impairment and oxidative stress.

    Science.gov (United States)

    El-Megharbel, Samy M; Hamza, Reham Z; Refat, Moamen S

    2015-01-25

    The main task of our present study is the preparation of newly complexes of Mg(II), Ca(II), Sr(II) and Ba(II) with diclofenac which succeeded to great extent in alleviating the side effects of diclofenac alone and ameliorating the kidney function parameters and antioxidant capacities with respect to diclofenac treated group alone. The Mg(II), Ca(II), Sr(II) and Ba(II) with diclofenac have been synthesized and characterized using infrared, electronic and (1)H NMR spectral, thermogravimetric and conductivity measurements. The diclofenac ligand has been found to act as bidentate chelating agent. Diclofenac complexes coordinate through the oxygen's of the carboxyl group. The molar ratio chelation is 1:2 (M(2+)-dic) with general formula [M(dic)2(H2O)2]⋅nH2O. Antibacterial screening of the alkaline earth metal complexes against Escherichia coli (Gram-ve), Bacillus subtilis (Gram+ve) and anti-fungal (Asperagillus oryzae, Asperagillus niger, Asperagillus flavus) were investigated. The kidney functions in male albino rats were ameliorated upon treatment with metal complexes of dic, which are represented by decreasing the levels of urea and uric acid to be located within normal values. The other looks bright spot in this article is the assessment of antioxidant defense system including SOD, CAT and MDA with the help of Sr(2+), Mg(2+) and Ca(2+)-dic complexes. The hormones related to kidney functions and stresses have been greatly ameliorated in groups treated with dic complexes in comparable with dic treated group.

  14. Accessing the nuclear symmetry energy in Ca+Ca collisions

    Directory of Open Access Journals (Sweden)

    Chbihi A.

    2012-07-01

    Full Text Available The status of the analysis of the INDRA-VAMOS experiement performed at GANIL, using the reactions 40,48Ca+40,48Ca reactions at 35AMeV, are presented. Isotopic distributions of fragments produced in multifragmentation events provide information on the importance of the surface term contribution in the symmetry energy by comparison to AMD predictions.

  15. Far-infrared radiation acutely increases nitric oxide production by increasing Ca{sup 2+} mobilization and Ca{sup 2+}/calmodulin-dependent protein kinase II-mediated phosphorylation of endothelial nitric oxide synthase at serine 1179

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jung-Hyun; Lee, Sangmi [Department of Molecular Medicine and Ewha Medical Research Institute, Ewha Womans University Medical School, Seoul 158-710 (Korea, Republic of); Cho, Du-Hyong [Department of Neuroscience, School of Medicine, Konkuk University, Seoul 143-701 (Korea, Republic of); Park, Young Mi [Department of Molecular Medicine and Ewha Medical Research Institute, Ewha Womans University Medical School, Seoul 158-710 (Korea, Republic of); Kang, Duk-Hee [Division of Nephrology, Department of Internal Medicine, Ewha Womans University Medical School, Seoul 158-710 (Korea, Republic of); Jo, Inho, E-mail: inhojo@ewha.ac.kr [Department of Molecular Medicine and Ewha Medical Research Institute, Ewha Womans University Medical School, Seoul 158-710 (Korea, Republic of)

    2013-07-12

    Highlights: •Far-infrared (FIR) radiation increases eNOS-Ser{sup 1179} phosphorylation and NO production in BAEC. •CaMKII and PKA mediate FIR-stimulated increases in eNOS-Ser{sup 1179} phosphorylation. •FIR increases intracellular Ca{sup 2+} levels. •Thermo-sensitive TRPV Ca{sup 2+} channels are unlikely to be involved in the FIR-mediated eNOS-Ser{sup 1179} phosphorylation pathway. -- Abstract: Repeated thermal therapy manifested by far-infrared (FIR) radiation improves vascular function in both patients and mouse model with coronary heart disease, but its underlying mechanism is not fully understood. Using FIR as a thermal therapy agent, we investigate the molecular mechanism of its effect on endothelial nitric oxide synthase (eNOS) activity and NO production. FIR increased the phosphorylation of eNOS at serine 1179 (eNOS-Ser{sup 1179}) in a time-dependent manner (up to 40 min of FIR radiation) in bovine aortic endothelial cells (BAEC) without alterations in eNOS expression. This increase was accompanied by increases in NO production and intracellular Ca{sup 2+} levels. Treatment with KN-93, a selective inhibitor of Ca{sup 2+}/calmodulin-dependent protein kinase II (CaMKII) and H-89, a protein kinase A inhibitor, inhibited FIR radiation-stimulated eNOS-Ser{sup 1179} phosphorylation. FIR radiation itself also increased the temperature of culture medium. As transient receptors potential vanilloid (TRPV) ion channels are known to be temperature-sensitive calcium channels, we explore whether TRPV channels mediate these observed effects. Reverse transcription-PCR assay revealed two TRPV isoforms in BAEC, TRPV2 and TRPV4. Although ruthenium red, a pan-TRPV inhibitor, completely reversed the observed effect of FIR radiation, a partial attenuation (∼20%) was found in cells treated with Tranilast, TRPV2 inhibitor. However, ectopic expression of siRNA of TRPV2 showed no significant alteration in FIR radiation-stimulated eNOS-Ser{sup 1179} phosphorylation. This

  16. RG-II from Panax ginseng C.A. Meyer suppresses asthmatic reaction

    Directory of Open Access Journals (Sweden)

    In Duk Jung

    2012-02-01

    Full Text Available In asthma, T helper 2 (TH2-type cytokines such as interleukin(IL-4, IL-5, and IL-13 are produced by activated CD4+ T cells.Dendritic cells played an important role in determining thefate of naïve T cells into either TH1 or TH2 cells. Wedetermined whether RG-II regulates the TH1/TH2 immuneresponse by using an ovalbumin-induced murine model ofasthma. RG-II reduced IL-4 production but increased interferon-gamma production, and inhibited GATA-3 geneexpression. RG-II also inhibited asthmatic reactions includingan increase in the number of eosinophils in bronchoalveolarlavage fluid, an increase in inflammatory cell infiltration inlung tissues, airway luminal narrowing, and airway hyperresponsiveness.This study provides evidence that RG-II plays acritical role in ameliorating the pathogenic process ofasthmatic inflammation in mice. These findings provide newinsights into the immunotherapeutic role of RG-II in terms ofits effects in a murine model of asthma. [BMB reports 2012;45(2: 79-84

  17. Radial velocities and metallicities from infrared Ca II triplet spectroscopy of open clusters II. Berkeley 23, King 1, NGC 559, NGC 6603 and NGC 7245

    CERN Document Server

    Carrera, R; Ospina, N; Balaguer-Nuñez, L; Jordi, C; Monteagudo, L

    2015-01-01

    Context: Open clusters are key to studying the formation and evolution of the Galactic disc. However, there is a deficiency of radial velocity and chemical abundance determinations for open clusters in the literature. Aims: We intend to increase the number of determinations of radial velocities and metallicities from spectroscopy for open clusters. Methods: We acquired medium-resolution spectra (R~8000) in the infrared region Ca II triplet lines (~8500 AA) for several stars in five open clusters with the long-slit IDS spectrograph on the 2.5~m Isaac Newton Telescope (Roque de los Muchachos Observatory, Spain). Radial velocities were obtained by cross-correlation fitting techniques. The relationships available in the literature between the strength of infrared Ca II lines and metallicity were also used to derive the metallicity for each cluster. Results: We obtain = 48.6+/-3.4, -58.4+/-6.8, 26.0+/-4.3 and -65.3+/-3.2 km s-1 for Berkeley 23, NGC 559, NGC 6603 and NGC 7245, respectively. We found [Fe/H] =-0.25+...

  18. Ca²⁺/calmodulin-dependent protein kinase II contributes to hypoxic ischemic cell death in neonatal hippocampal slice cultures.

    Directory of Open Access Journals (Sweden)

    Qing Lu

    Full Text Available We have recently shown that p38MAP kinase (p38MAPK stimulates ROS generation via the activation of NADPH oxidase during neonatal hypoxia-ischemia (HI brain injury. However, how p38MAPK is activated during HI remains unresolved and was the focus of this study. Ca²⁺/calmodulin-dependent protein kinase II (CaMKII plays a key role in brain synapse development, neural transduction and synaptic plasticity. Here we show that CaMKII activity is stimulated in rat hippocampal slice culture exposed to oxygen glucose deprivation (OGD to mimic the condition of HI. Further, the elevation of CaMKII activity, correlated with enhanced p38MAPK activity, increased superoxide generation from NADPH oxidase as well as necrotic and apoptotic cell death. All of these events were prevented when CaMKII activity was inhibited with KN93. In a neonatal rat model of HI, KN93 also reduced brain injury. Our results suggest that CaMKII activation contributes to the oxidative stress associated with neural cell death after HI.

  19. Probing the accessibility of the Mn(4)Ca cluster in photosystem II : Channels calculation, noble gas derivatization, and cocrystallization with DMSO

    NARCIS (Netherlands)

    Gabdulkhakov, Azat; Guskov, Albert; Broser, Matthias; Kern, Jan; Müh, Frank; Saenger, Wolfram; Zouni, Athina

    2009-01-01

    Using the 2.9 A resolution structure of the membrane-intrinsic protein-cofactor complex photosystem II (PSII) from the cyanobacterium Thermosynechococcus elongatus, we calculated and characterized nine possible substrate/product channels leading to/away from the Mn(4)Ca cluster, where water is oxidi

  20. Mutations in the Bacillus thuringiensis Cry1Ca toxin demonstrate the role of domain II and III in the specificity towards Spodoptera exigua larvae

    NARCIS (Netherlands)

    Herrero Sendra, S.; González-Cabrera, J.; Ferré, J.; Bakker, P.L.; Maagd, de R.A.

    2004-01-01

    Several mutants of the Bacillus thuringiensis Cry1Ca toxin affected with regard to specific activity towards Spodoptera exigua were studied. Alanine was used to replace single residues in loops 2 and 3 of domain II (mutant pPB19) and to replace residues 541-544 in domain III (mutant pPB20). Addition

  1. A significant but rather mild contribution of T286 autophosphorylation to Ca2+/CaM-stimulated CaMKII activity.

    Directory of Open Access Journals (Sweden)

    Steven J Coultrap

    Full Text Available BACKGROUND: Autophosphorylation of the Ca(2+/calmodulin (CaM-dependent protein kinase II (CaMKII at T286 generates partially Ca(2+/CaM-independent "autonomous" activity, which is thought to be required for long-term potentiation (LTP, a form of synaptic plasticity thought to underlie learning and memory. A requirement for T286 autophosphorylation also for efficient Ca(2+/CaM-stimulated CaMKII activity has been described, but remains controversial. METHODOLOGY/PRINCIPAL FINDINGS: In order to determine the contribution of T286 autophosphorylation to Ca(2+/CaM-stimulated CaMKII activity, the activity of CaMKII wild type and its phosphorylation-incompetent T286A mutant was compared. As the absolute activity can vary between individual kinase preparations, the activity was measured in six different extracts for each kinase (expressed in HEK-293 cells. Consistent with measurements on purified kinase (from a baculovirus/Sf9 cell expression system, CaMKII T286A showed a mildly but significantly reduced rate of Ca(2+/CaM-stimulated phosphorylation for two different peptide substrates (to ~75-84% of wild type. Additional slower CaMKII autophosphorylation at T305/306 inhibits stimulation by Ca(2+/CaM, but occurs only minimally for CaMKII wild type during CaM-stimulated activity assays. Thus, we tested if the T286A mutant may show more extensive inhibitory autophosphorylation, which could explain its reduced stimulated activity. By contrast, inhibitory autophosphorylation was instead found to be even further reduced for the T286A mutant under our assay conditions. On a side note, the phospho-T305 antibody showed some basal background immuno-reactivity also with non-phosphorylated CaMKII, as indicated by T305/306A mutants. CONCLUSIONS/SIGNIFICANCE: These results indicate that Ca(2+/CaM-stimulated CaMKII activity is mildly (~1.2-1.3fold further increased by additional T286 autophosphorylation, but that this autophosphorylation is not required for the major

  2. Role of Ca++ in Shoot Gravitropism. [avena

    Science.gov (United States)

    Rayle, D. L.

    1985-01-01

    A cornerstone in the argument that Ca(2+) levels may regulate growth is the finding the EGTA promotes straight growth. The usual explanation for these results is that Ca(2+) chelation from cell walls results in wall loosening and thus accelerated straight growth. The ability of frozen-thawed Avena coleoptile tissue (subjected to 15g tension) to extend in response to EGTA and Quin II was examined. The EGTA when applied in weakly buffered (i.e., 0.1mM) neutral solutions initiates rapid extension. When the buffer strength is increased, similar concentrations of EGTA produce no growth response. This implies when EGTA liberated protons are released upon Ca(2+) chelation they can either initiate acid growth (low buffer conditions) or if consumed (high buffer conditions) have no effect. Thus Ca(2+) chelation in itself apparently does not result in straight growth.

  3. Pressure-induced structural transformation of CaC2

    Science.gov (United States)

    Wang, Lu; Huang, Xiaoli; Li, Da; Huang, Yanping; Bao, Kuo; Li, Fangfei; Wu, Gang; Liu, Bingbing; Cui, Tian

    2016-05-01

    The high pressure structural changes of calcium carbide CaC2 have been investigated with Raman spectroscopy and synchrotron X-ray diffraction (XRD) techniques in a diamond anvil cell at room temperature. At ambient conditions, two forms of CaC2 co-exist. Above 4.9 GPa, monoclinic CaC2-ii diminished indicating the structural phase transition from CaC2-ii to CaC2-i. At about 7.0 GPa, both XRD patterns and Raman spectra confirmed that CaC2-i transforms into a metallic Cmcm structure which contains polymeric carbon chains. Along with the phase transition, the isolated C2 dumbbells are polymerized into zigzag chains resulting in a large volume collapse with 22.4%. Above 30.0 GPa, the XRD patterns of CaC2 become featureless and remain featureless upon decompression, suggesting an irreversible amorphization of CaC2.

  4. Construction of a Ca II Core-to-Wing Ratio Image

    Science.gov (United States)

    Roberts, H.

    2015-12-01

    To understand Earth's climate, we must first understand the Sun. However, there are still significant uncertainties associated with both the fundamental mechanisms of solar variability and how they enter into the Earth's climate system. An important method to study the causes of solar variability can be found through the analysis of solar images. The Precision Solar Photometric Telescope (PSPT) located at the Mauna Loa Solar Observatory (MLSO) acquires images of the Sun in three different photometric bands to monitor the evolution of solar surface features that change over the course of a solar cycle. These images provide a complete knowledge about the Sun by targeting different layers of the solar atmosphere. Though raw images are meaningful and important, precision image processing is required to remove instrumental artifacts and false features that may appear in these images prior to usage for scientific purposes. A scientific application of the high precision solar images is investigated by analyzing a set of narrow band of Calcium II K core and wing images. The Core and Wing images are processed to remove the influence of the center-to-limb variation; the resultant core-to-wing ratio image enhances the appearance of network structures on the entire solar disk along with the more obvious facula and plage brightening associated with the passage of active regions.

  5. (41)Ca in Tooth Enamel. Part II: A means for retrospective biological neutron dosimetry in atomic bomb survivors.

    Science.gov (United States)

    Rühm, W; Wallner, A; Cullings, H; Egbert, S D; El-Faramawy, N; Faestermann, T; Kaul, D; Knie, K; Korschinek, G; Nakamura, N; Roberts, J; Rugel, G

    2010-08-01

    (41)Ca is produced mainly by absorption of low-energy neutrons on stable (40)Ca. We used accelerator mass spectrometry (AMS) to measure (41)Ca in enamel of 16 teeth from 13 atomic bomb survivors who were exposed to the bomb within 1.2 km from the hypocenter in Hiroshima. In our accompanying paper (Wallner et al., Radiat. Res. 174, 000-000, 2010), we reported that the background-corrected (41)Ca/Ca ratio decreased from 19.5 x 10(-15) to 2.8 x 10(-15) with increasing distance from the hypocenter. Here we show that the measured ratios are in good correlation with gamma-ray doses assessed by electron paramagnetic resonance (EPR) in the same enamel samples, and agree well with calculated ratios based on either the current Dosimetry System 2002 (DS02) or more customized dose estimates where the regression slope as obtained from an errors-in-variables linear model was about 0.85. The calculated DS02 neutron dose to the survivors was about 10 to 80 mGy. The low-energy neutrons responsible for (41)Ca activation contributed variably to the total neutron dose depending on the shielding conditions. Namely, the contribution was smaller (10%) when shielding conditions were lighter (e.g., outside far away from a single house) and was larger (26%) when they were heavier (e.g., in or close to several houses) because of local moderation of neutrons by shielding materials. We conclude that AMS is useful for verifying calculated neutron doses under mixed exposure conditions with gamma rays.

  6. (Meta)stable CaC{sub 2}; (Meta)stabiles CaC{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Glaser, J.; Dill, S.; Marzini, M.; Mayer, H.A.; Meyer, H.J. [Tuebingen Univ. (Germany). Inst. fuer Anorganische Chemie

    2001-05-01

    One out of four modifications of CaC{sub 2} is the so-called metastable calcium carbide, CaC{sub 2}-III, which was synthesized as pure material. It forms by heating monoclinic CaC{sub 2}-II (C2/c) above 150 C and remains stable after cooling down to room temperature. The structure was refined from X-ray powder patterns (C2/m, Z = 4, a = 722.6(1) pm, b = 385.26(7) pm, c = 737.6(1) pm, {beta} = 107.345(2) ). After grinding CaC{sub 2}-III transforms back into CaC{sub 2}-II. Heating CaC{sub 2}-III induces a reversible phase transition into the cubic modification (CaC{sub 2}-IV) at 460 C. Differences between the three different structures of CaC{sub 2} I-III, being stable at ambient conditions are also shown by {sup 13}C-MAS-NMR measurements, especially the presence of two distinct types of carbon atoms in the structure of the title compound. (orig.)

  7. Detection of Low-Level Activities in Solar-Analog Stars from the Emission Strengths of Ca II 3934 Line

    CERN Document Server

    Takeda, Yoichi; Honda, Satoshi; Kawanomoto, Satoshi; Ando, Hiroyasu; Sakurai, Takashi

    2012-01-01

    Activity studies of solar-type stars, especially with reference to the status of our current Sun among them, have exposed the importance of (1) homogeneously selecting the sample stars and (2) reliably evaluating their activities down to a considerably low level. Motivated by these requirements, we conducted an extensive study on the activities of 118 solar-analog stars (of sufficiently similar properties to each other) by measuring the emission strength at the core of Ca II 3933.663 line (K line) on the high-dispersion spectrogram obtained by Subaru/HDS, where special attention was paid to correctly detecting the chromospheric emission by removing the wing-fitted photospheric profile calculated from the classical solar model atmosphere. This enabled us to detect low-level activities down to log R' ~ -5.4 (R' is the ratio of the chromospheric core emission flux to the total bolometric flux), by which we could detect subtle activity differences which were indiscernible in previous studies. Regarding the Sun, w...

  8. Full-Disk Chromospheric Vector Magnetograms with Ca II 854.2 nm line: Some Promising Applications

    Science.gov (United States)

    Gosain, Sanjay; Harvey, J. W.; Harker, Brian; Pillet, V. M.; Pevtsov, Alexei A.; Marble, Andrew R.; Bertello, Luca; + SOLIS-Team

    2016-05-01

    Over the last decade, the focus of solar magnetometry has shifted outward from the photosphere to the chromospheric layers. The reasons for this are many. With regards to instrumentation faster detectors with more sensitivity have become available, as have fast electro-optic modulators. Also, there are several potential benefits of observing vector fields in the chromospheric layer as the magnetic field is more force-free in this layer as compared to the photosphere. Coronal force-free field extrapolations are more reliable using chromospheric fields as the lower boundary condition and free magnetic energy is readily computed using the magnetic virial theorem. Recently, a full Stokes polarimeter for the chromospheric Ca II 854.2 nm spectral line was developed and installed in the Vector Spectromagnetograph (VSM) instrument on the Synoptic Optical Long-term Investigations of the Sun (SOLIS) telescope. We present details of this new polarimeter, full disk spectropolarimetric observations and vector magnetograms of the chromosphere, and examples of some promising applications (e.g., maps of normal component of electric current density in the chromosphere, free magnetic energy estimated using virial theorem, and non-potentiality parameter magnetic shear angle).This work utilizes SOLIS data obtained by the NSO Integrated Synoptic Program (NISP), managed by the National Solar Observatory, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc. under a cooperative agreement with the National Science Foundation

  9. The wings of Ca II H and K as photospheric diagnostics and the reliability of one-dimensional photosphere modeling

    CERN Document Server

    Sheminova, V A

    2012-01-01

    The extended wings of the Ca II H and K lines provide excellent diagnostics of the temperature stratification of the photosphere of the Sun and of other cool stars, thanks to their LTE opacities and source functions and their large span in formation height. The aim of this study is to calibrate the usage of the H and K wings in one-dimensional interpretation of spatially averaged spectra and in deriving per-pixel stratifications from resolved spectra. I use multi-dimensional simulations of solar convection to synthesize the H and K wings, derive one-dimensional models from these wings as if they were observed, and compare the resulting models to the actual simulation input. I find that spatially-averaged models constructed from the synthesized wings generally match the simulation averages well, except for the deepest layers of the photosphere where large thermal inhomogeneities and Planck-function nonlinearity gives large errors. The larger the inhomogeneity, the larger the latter. The presence of strong netw...

  10. High-Resolution Mn EXAFS of the Oxygen-Evolving Complex inPhotosystem II: Structural Implications for the Mn4Ca Cluster

    Energy Technology Data Exchange (ETDEWEB)

    Yano, Junko; Pushkar, Yulia; Glatzel, Pieter; Lewis, Azul; Sauer,Kenneth; Messinger, Johannes; Bergmann, Uwe; Yachandra, Vittal

    2005-09-06

    The biological generation of oxygen by the oxygen-evolving complex in photosystem II (PS II) is one of natures most important reactions. The recent X-ray crystal structures, while limited by resolutions of 3.2 to 3.5 A, have located the electron density associated with the Mn4Ca complex within the multi-protein PS II complex. Detailed structures critically depend on input from spectroscopic techniques such as EXAFS and EPR/ENDOR, as the XRD resolution does not allow for accurate determination of the position of Mn/Ca or the bridging and terminal ligand atoms. The number and distances of Mn-Mn/Ca/ligand interactions determined from EXAFS provide important constraints for the structure of the Mn cluster. Here we present data from a high-resolution EXAFS method using a novel multi-crystal monochromator that show three short Mn-Mn distances between 2.7 and 2.8 A and hence the presence of three di-mu-oxobridged units in the Mn4Ca cluster. This result imposes clear limitations on the proposed structures based on spectroscopic and diffraction data and provides input for refining such structures.

  11. Sonoma County, CA, 2013 Lidar

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Sonoma County Vegetation Mapping and LiDAR Consortium retained WSI to provide lidar and Orthophoto data and derived products in Sonoma County, CA. A classified LAS...

  12. CA125 in ovarian cancer

    DEFF Research Database (Denmark)

    Duffy, M J; Bonfrer, J M; Kulpa, J

    2005-01-01

    value in the detection of early ovarian cancer. At present, therefore, CA125, either alone or in combination with other modalities, cannot be recommended for screening for ovarian cancer in asymptomatic women outside the context of a randomized controlled trial. Preoperative levels in postmenopausal...... women, however, may aid the differentiation of benign and malignant pelvic masses. Serial levels during chemotherapy for ovarian cancer are useful for assessing response to treatment. Although serial monitoring following initial chemotherapy can lead to the early detection of recurrent disease......CA125 is currently the most widely used tumor marker for ovarian epithelial cancer. The aim of this article is to provide guidelines for the routine clinical use of CA125 in patients with ovarian cancer. Due to lack of sensitivity for stage I disease and lack of specificity, CA125 is of little...

  13. Hyperexcitability and changes in activities of Ca2+/calmodulin-dependent kinase II and mitogen-activated protein kinase in the hippocampus of rats exposed to 1-bromopropane.

    Science.gov (United States)

    Fueta, Yukiko; Fukunaga, Kohji; Ishidao, Toru; Hori, Hajime

    2002-12-20

    Chronic inhalation of 1-bromopropane (1-BP), a substitute of ozone-depleting chlorofluorocarbons, has been suspected of having central neurotoxicity (Clinical Neurology and Neurosurgery 101 (1999) 199; Journal of Occupational Health 44 (2002) 1) for humans. In animal experiments, 1-BP inhalation (1500 ppm) caused hyperexcitability in the CA1 and the dentate gyrus (DG) [Journal of Occupational Health 42 (2000) 149, Journal of Occupational Health 44 (2002) 156]. We studied whether the hyperexcitability is associated with changes of Ca2+/calmodulin-dependent kinase II (CaMKII), mitogen-activated protein kinase (MAPK), and protein kinase C (PKC). Male Wistar rats were exposed to 1-BP for 6 hours in a day in an exposure chamber with a concentration of 700 ppm for 8 weeks. After the inhalation, paired-pulse ratios of field excitatory postsynaptic potentials and population spikes (PSs) were analyzed in the CA1 and DG of hippocampal slices. Control rats were then given fresh air in the inhalation chamber. Semiquantitative immunoblotting analyses of protein kinases using antibodies against active and conventional protein kinases were done using the whole hippocampus. A paired-pulse ratio of PS was increased at the 5 ms interpulse interval in the CA1 and at the 10-20 ms interpulse intervals in the DG. The amount of active MAPK and total amount of CaMKIIalpha and beta were significantly increased by 28, 29, and 46% compared to control, respectively, without any change in PKC activity. In contrast, the amount of active CaMKIIbeta was decreased to 78%. These results suggest that modifications of intracellular signaling cascades are associated with hyperexcitability that occurred in the hippocampal formation of rats exposed to the chronic inhalation of 1-BP.

  14. Cathodic behavior of molten CaCl2-CaO and CaCl2-NaCl-CaO

    Science.gov (United States)

    Wang, Shu-Lan; Wang, Wei; Li, Shi-Chao; Cao, Shan-Hui

    2010-12-01

    The cathodic behavior of molten CaCl2, CaCl2-CaO and equimolar CaCl2-NaCl-CaO was studied by cyclic voltammograms and constant potential polarization at temperatures of 1123 to 1173 K on molybdenum and titanium electrodes. The diffusion coefficient of Ca2+ (CaO) in molten CaCl2-CaO was calculated from the linear relationship between the square root of scan rate and the peak current density. The deposition potentials and the potential temperature coefficient of CaO in molten CaCl2-0.5mol%CaO and CaCl2-NaCl-0.5mol%CaO were also obtained from their cyclic voltammograms. The result shows that CaO is more easily reduced than CaCl2. The addition of NaCl in molten CaCl2-CaO induces the underpotential electrodeposition of CaO.

  15. Generation and behavior characterization of CaMKIIβ knockout mice.

    Directory of Open Access Journals (Sweden)

    Adam D Bachstetter

    Full Text Available The calcium/calmodulin-dependent protein kinase II (CaMKII is abundant in the brain, where it makes important contributions to synaptic organization and homeostasis, including playing an essential role in synaptic plasticity and memory. Four genes encode isoforms of CaMKII (α, β, δ, γ, with CaMKIIα and CaMKIIβ highly expressed in the brain. Decades of molecular and cellular research, as well as the use of a large number of CaMKIIα mutant mouse lines, have provided insight into the pivotal roles of CaMKIIα in brain plasticity and cognition. However, less is known about the CaMKIIβ isoform. We report the development and extensive behavioral and phenotypic characterization of a CaMKIIβ knockout (KO mouse. The CaMKIIβ KO mouse was found to be smaller at weaning, with an altered body mass composition. The CaMKIIβ KO mouse showed ataxia, impaired forelimb grip strength, and deficits in the rotorod, balance beam and running wheel tasks. Interestingly, the CaMKIIβ KO mouse exhibited reduced anxiety in the elevated plus maze and open field tests. The CaMKIIβ KO mouse also showed cognitive impairment in the novel object recognition task. Our results provide a comprehensive behavioral characterization of mice deficient in the β isoform of CaMKII. The neurologic phenotypes and the construction of the genotype suggest the utility of this KO mouse strain for future studies of CaMKIIβ in brain structure, function and development.

  16. The emerging role of CaMKII in cancer.

    Science.gov (United States)

    Wang, Yan-yang; Zhao, Ren; Zhe, Hong

    2015-05-20

    Ca2+/calmodulin-dependent protein kinase II (CaMKII) is a multifunctional serine/threonine kinases best known for its critical role in learning and memory. Recent studies suggested that high levels of CaMKII also expressed in variety of malignant diseases. In this review, we focus on the structure and biology properties of CaMKII, including the role of CaMKII in the regulation of cancer progression and therapy response. We also describe the role of CaMKII in the diagnosis of different kinds of cancer and recent progress in the development of CaMKII inhibitors. These data establishes CaMKII as a novel target whose modulation presents new opportunities for cancer diagnosis and treatment.

  17. CaMKII in sinoatrial node physiology and dysfunction

    Directory of Open Access Journals (Sweden)

    Yuejin eWu

    2014-03-01

    Full Text Available The calcium and calmodulin dependent protein kinase II (CaMKII is present in sinoatrial node (SAN pacemaker cells and is required for physiological fight or flight SAN beating rate responses. Inhibition of CaMKII in SAN does not affect baseline heart rate, but reduces heart rate increases in response to physiological stress. CaMKII senses intracellular calcium (Ca2+ changes, oxidation status and hyperglycemia to phosphorylate substrates that regulate Ca2+-sensitive proteins, such as L-type Ca2+ channels, phospholamban (PLN, and cardiac ryanodine receptors (RyR2. All of these substrates are involved in the SAN pacemaking mechanism. Excessive CaMKII activity, as occurs under pathological conditions such as heart failure, ischemia and diabetes, can promote intracellular Ca2+ overload and reactive oxygen species (ROS production. Oxidation of CaMKII (ox-CaMKII locks CaMKII into a constitutively active configuration that contributes to SAN cell apoptosis and fibrosis. This ox-CaMKII-mediated loss of functional SAN cells contributes to sinoatrial node dysfunction (SND and sudden death. Thus, CaMKII has emerged as a central regulator of physiological SAN responses and a key determinant of SND.

  18. Physicochemical impact studies of gamma rays on "aspirin" analgesics drug and its metal complexes in solid form: Synthesis, spectroscopic and biological assessment of Ca(II), Mg(II), Sr(II) and Ba(II) aspirinate complexes

    Science.gov (United States)

    Refat, Moamen S.; Sharshar, T.; Elsabawy, Khaled M.; Heiba, Zein K.

    2013-09-01

    Metal aspirinate complexes, M2(Asp)4, where M is Mg(II), Ca(II), Sr(II) or Ba(II) are formed by refluxed of aspirin (Asp) with divalent non-transition metal ions of group (II) and characterized by elemental analysis and spectroscopic measurements (infrared, electronic, 1H NMR, Raman, X-ray powder diffraction and scanning electron microscopy). Elemental analysis of the chelates suggests the stoichiometry is 1:2 (metal:ligand). Infrared spectra of the complexes agree with the coordination to the central metal atom through three donation sites of two oxygen atoms of bridge bidentate carboxylate group and oxygen atom of sbnd Cdbnd O of acetyl group. Infrared spectra coupled with the results of elemental analyzes suggested a distorted octahedral structure for the M(II) aspirinate complexes. Gamma irradiation was tested as a method for stabilization of aspirin as well as their complexes. The effect of gamma irradiation, with dose of 80 Gy, on the properties of aspirinate complexes was studied. The aspirinate chelates have been screened for their in vitro antibacterial activity against four bacteria, gram-positive (Bacillus subtilis and Staphylococcus aureus) and gram-negative (Escherichia coli and Pseudomonas aeruginosa) and two strains of fungus (Aspergillus flavus and Candida albicans). The metal chelates were shown to possess more antibacterial activity than the free aspirin chelate.

  19. CA on CD评析

    Institute of Scientific and Technical Information of China (English)

    周秀会

    2007-01-01

    结合作者使用 CA On CD 的经验和体会,全面而具体地分析了 CA on CD 的使用功能,明确了其优点及不足之处,同时,针对这些不足之处进行了探索和尝试,提出了利用检索技巧解决这些不足之处的方法。并结合实例详细说明。

  20. The site of net absorption of Ca from the intestinal tract of growing pigs and effect of phytic acid, Ca level and Ca source on Ca digestibility.

    Science.gov (United States)

    González-Vega, J Caroline; Walk, Carrie L; Liu, Yanhong; Stein, Hans H

    2014-01-01

    An experiment was conducted to test the hypothesis that the standardised digestibility of Ca in calcium carbonate and Lithothamnium calcareum Ca is not different regardless of the level of dietary Ca, and that phytic acid affects the digestibility of Ca in these two ingredients to the same degree. The objectives were to determine where in the intestinal tract Ca absorption takes place and if there are measurable quantities of basal endogenous Ca fluxes in the stomach, small intestine or large intestine. Diets contained calcium carbonate or L. calcareum Ca as the sole source of Ca, 0% or 1% phytic acid and 0.4% or 0.8% Ca. A Ca-free diet was also formulated and used to measure endogenous fluxes and losses of Ca. Nine growing pigs (initial body weight 23.8 ± 1.3 kg) were cannulated in the duodenum and in the distal ileum, and faecal, ileal and duodenal samples were collected. Duodenal endogenous fluxes of Ca were greater (p phytic acid, but decreased (p phytic acid, but may be affected by dietary Ca level depending on the Ca source. Calcium from calcium carbonate is mostly absorbed before the duodenum, but Ca from L. calcareum Ca is mostly absorbed in the jejunum and ileum.

  1. The diagnostic value of joint detection of serum CA19-9, CA125 and CA242 for cholangiocarcinoma

    Institute of Scientific and Technical Information of China (English)

    Cui Da-Peng; Han Lei; Liu Zhen-Xian; Yang He; Zhang Ying-Chun

    2016-01-01

    Objective:To study the diagnostic value of joint detection of serum CA19-9, CA125 and CA242 for cholangiocarcinoma.Methods:A total of 35 patients with cholangiocarcinoma who received surgical resection in our hospital were selected as malignant group, 30 patients with cholelithiasis who received surgical resection in our hospital during the same period were selected as benign group, serum samples were collected before surgery to determine CA19-9, CA125 and CA242 content, and cholangiocarcinoma tissue and normal bile duct tissue were collected after surgery to determine the content of proliferation and invasion molecules. Results:Serum CA19-9, CA125 and CA242 levels of malignant group were significantly higher than those of control group; PROX-1, Ki-67, Bcl-2, Bad, Gab1, LOXL2, TRPM7 and CXCL12 levels in cholangiocarcinoma tissue were higher than those in benign bile duct tissue, and E-cadherin level was lower than that in benign bile duct tissue; serum CA19-9, CA125 and CA242 levels were positively correlated with PROX-1, Ki-67, Bcl-2, Bad, Gab1, LOXL2, TRPM7 and CXCL12 levels, and negatively correlated with E-cadherin level.Conclusion:Joint detection of serum CA19-9, CA125 and CA242 can not only provide reference for the diagnosis of cholangiocarcinoma, but can also provide basis for the evaluation of proliferation, invasion and other malignant biological behaviors.

  2. Quantum mechanics/molecular mechanics simulation of the ligand vibrations of the water-oxidizing Mn4CaO5 cluster in photosystem II.

    Science.gov (United States)

    Nakamura, Shin; Noguchi, Takumi

    2016-10-11

    During photosynthesis, the light-driven oxidation of water performed by photosystem II (PSII) provides electrons necessary to fix CO2, in turn supporting life on Earth by liberating molecular oxygen. Recent high-resolution X-ray images of PSII show that the water-oxidizing center (WOC) is composed of an Mn4CaO5 cluster with six carboxylate, one imidazole, and four water ligands. FTIR difference spectroscopy has shown significant structural changes of the WOC during the S-state cycle of water oxidation, especially within carboxylate groups. However, the roles that these carboxylate groups play in water oxidation as well as how they should be properly assigned in spectra are unresolved. In this study, we performed a normal mode analysis of the WOC using the quantum mechanics/molecular mechanics (QM/MM) method to simulate FTIR difference spectra on the S1 to S2 transition in the carboxylate stretching region. By evaluating WOC models with different oxidation and protonation states, we determined that models of high-oxidation states, Mn(III)2Mn(IV)2, satisfactorily reproduced experimental spectra from intact and Ca-depleted PSII compared with low-oxidation models. It is further suggested that the carboxylate groups bridging Ca and Mn ions within this center tune the reactivity of water ligands bound to Ca by shifting charge via their π conjugation.

  3. MicroRNA-145 suppresses ROS-induced Ca{sup 2+} overload of cardiomyocytes by targeting CaMKIIδ

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Min-Ji [Cardiovascular Research Institute, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Jang, Jin-Kyung [College of Pharmacy, Sookmyung Women’s University, 52 HyoChangWon-Gil, Yongsan-ku, Seoul 140-742 (Korea, Republic of); Ham, Onju; Song, Byeong-Wook; Lee, Se-Yeon [Cardiovascular Research Institute, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Lee, Chang Yeon; Park, Jun-Hee [Department of Integrated Omics for Biomedical Sciences, Graduate School, Yonsei University, 50 Yonsei-ro, Seodamun-gu, Seoul 120-759 (Korea, Republic of); Lee, Jiyun; Seo, Hyang-Hee [Cardiovascular Research Institute, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Choi, Eunhyun [Severance Integrative Research Institute for Cerebral and Cardiovascular Disease, Yonsei University Health System, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Jeon, Woo-min [Department of Animal Resource, Sahmyook University, Seoul 139-742 (Korea, Republic of); Hwang, Hye Jin [Cardiovascular Research Institute, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Shin, Hyun-Taek [College of Pharmacy, Sookmyung Women’s University, 52 HyoChangWon-Gil, Yongsan-ku, Seoul 140-742 (Korea, Republic of); and others

    2013-06-14

    Highlights: •CaMKIIδ mediates H{sub 2}O{sub 2}-induced Ca{sup 2+} overload in cardiomyocytes. •miR-145 can inhibit Ca{sup 2+} overload. •A luciferase assay confirms that miR-145 functions as a CaMKIIδ-targeting miRNA. •Overexpression of miR-145 regulates CaMKIIδ-related genes and ameliorates apoptosis. -- Abstract: A change in intracellular free calcium (Ca{sup 2+}) is a common signaling mechanism of reperfusion-induced cardiomyocyte death. Calcium/calmodulin dependent protein kinase II (CaMKII) is a critical regulator of Ca{sup 2+} signaling and mediates signaling pathways responsible for functions in the heart including hypertrophy, apoptosis, arrhythmia, and heart disease. MicroRNAs (miRNA) are involved in the regulation of cell response, including survival, proliferation, apoptosis, and development. However, the roles of miRNAs in Ca{sup 2+}-mediated apoptosis of cardiomyocytes are uncertain. Here, we determined the potential role of miRNA in the regulation of CaMKII dependent apoptosis and explored its underlying mechanism. To determine the potential roles of miRNAs in H{sub 2}O{sub 2}-mediated Ca{sup 2+} overload, we selected and tested 6 putative miRNAs that targeted CaMKIIδ, and showed that miR-145 represses CaMKIIδ protein expression and Ca{sup 2+} overload. We confirmed CaMKIIδ as a direct downstream target of miR-145. Furthermore, miR-145 regulates Ca{sup 2+}-related signals and ameliorates apoptosis. This study demonstrates that miR-145 regulates reactive oxygen species (ROS)-induced Ca{sup 2+} overload in cardiomyocytes. Thus, miR-145 affects ROS-mediated gene regulation and cellular injury responses.

  4. Determination of the membrane topology of the small EF-hand Ca2+-sensing proteins CaBP7 and CaBP8.

    Directory of Open Access Journals (Sweden)

    Hannah V McCue

    Full Text Available The CaBPs represent a subfamily of small EF-hand containing calcium (Ca(2+-sensing proteins related to calmodulin that regulate key ion channels in the mammalian nervous system. In a recent bioinformatic analyses we determined that CaBP7 and CaBP8 form an evolutionarily distinct branch within the CaBPs (also known as the calneurons a finding that is consistent with earlier observations characterising a putative C-terminal transmembrane (TM spanning helix in each of these proteins which is essential for their sub-cellular targeting to the Golgi apparatus and constitutive secretory vesicles. The C-terminal position of the predicted TM-helix suggests that CaBP7 and CaBP8 could be processed in a manner analogous to tail-anchored integral membrane proteins which exhibit the ability to insert across membranes post-translationally. In this study we have investigated the topology of CaBP7 and CaBP8 within cellular membranes through a combination of trypsin protection and epitope accessibility analyses. Our results indicate that the TM-helices of CaBP7 and CaBP8 insert fully across membranes such that their extreme C-termini are luminal. The observed type-II membrane topology is consistent with processing of CaBP7 and CaBP8 as true tail-anchored proteins. This targeting mechanism is distinct from any other calmodulin related Ca(2+-sensor and conceivably underpins unique physiological functions of these proteins.

  5. Fine structure of the age-chromospheric activity relation in solar-type stars. I. The Ca II infrared triplet: Absolute flux calibration

    Science.gov (United States)

    Lorenzo-Oliveira, D.; Porto de Mello, G. F.; Dutra-Ferreira, L.; Ribas, I.

    2016-10-01

    Context. Strong spectral lines are useful indicators of stellar chromospheric activity. They are physically linked to the convection efficiency, differential rotation, and angular momentum evolution and are a potential indicator of age. However, for ages > 2 Gyr, the age-activity relationship remains poorly constrained thus hampering its full application. Aims: The Ca II infrared triplet (IRT lines, λλ 8498, 8542, and 8662) has been poorly studied compared to classical chromospheric indicators. We report in this paper absolute chromospheric fluxes in the three Ca II IRT lines, based on a new calibration tied to up-to-date model atmospheres. Methods: We obtain the Ca II IRT absolute fluxes for 113 FGK stars from high signal-to-noise ratio (S/N) and high-resolution spectra covering an extensive domain of chromospheric activity levels. We perform an absolute continuum flux calibration for the Ca II IRT lines anchored in atmospheric models calculated as an explicit function of effective temperatures (Teff), metallicity ([Fe/H]), and gravities (log g) avoiding the degeneracy usually present in photometric continuum calibrations based solely on color indices. Results: The internal uncertainties achieved for continuum absolute flux calculations are ≈2% of the solar chromospheric flux, one order of magnitude lower than for photometric calibrations. Using Monte Carlo simulations, we gauge the impact of observational errors on the final chromospheric fluxes due to the absolute continuum flux calibration and find that Teffuncertainties are properly mitigated by the photospheric correction leaving [Fe/H] as the dominating factor in the chromospheric flux uncertainty. Conclusions: Across the FGK spectral types, the Ca II IRT lines are sensitive to chromospheric activity. The reduced internal uncertainties reported here enable us to build a new chromospheric absolute flux scale and explore the age-activity relation from the active regime down to very low activity levels and

  6. Isotopic Effects on Stereodynamics for Ca+HCI, Ca+DCI, and Ca+TClReactions

    Institute of Scientific and Technical Information of China (English)

    Li-zhi Wang; Chuan-lu Yang; Jing-juan Liang; Jing Xiao; Qing-gang Zhang

    2011-01-01

    The vector correlations in Ca+HC1,Ca+DCI,and Ca+TCI reactions have been investigated by means of the quasi-classical trajectory calculations on PES constructed by means of multireference configuration interaction.The distributions of P(θr),P(Φr) and the PDDCSs of (2π/σ)(dσ00/dωt),(2π/σ)(dσ20/dωt),(2π/σ)(dσ22+/dωt),(2π/σ)(dσ21-/dωt) have been calculated based on the surface.The remarkable isotopic effects in the reactions are observed,and the mechanism which may be ascribed to different mass factors is discussed.

  7. EMRE Is a Matrix Ca(2+) Sensor that Governs Gatekeeping of the Mitochondrial Ca(2+) Uniporter.

    Science.gov (United States)

    Vais, Horia; Mallilankaraman, Karthik; Mak, Don-On Daniel; Hoff, Henry; Payne, Riley; Tanis, Jessica E; Foskett, J Kevin

    2016-01-26

    The mitochondrial uniporter (MCU) is an ion channel that mediates Ca(2+) uptake into the matrix to regulate metabolism, cell death, and cytoplasmic Ca(2+) signaling. Matrix Ca(2+) concentration is similar to that in cytoplasm, despite an enormous driving force for entry, but the mechanisms that prevent mitochondrial Ca(2+) overload are unclear. Here, we show that MCU channel activity is governed by matrix Ca(2+) concentration through EMRE. Deletion or charge neutralization of its matrix-localized acidic C terminus abolishes matrix Ca(2+) inhibition of MCU Ca(2+) currents, resulting in MCU channel activation, enhanced mitochondrial Ca(2+) uptake, and constitutively elevated matrix Ca(2+) concentration. EMRE-dependent regulation of MCU channel activity requires intermembrane space-localized MICU1, MICU2, and cytoplasmic Ca(2+). Thus, mitochondria are protected from Ca(2+) depletion and Ca(2+) overload by a unique molecular complex that involves Ca(2+) sensors on both sides of the inner mitochondrial membrane, coupled through EMRE.

  8. Pulse electron paramagnetic resonance studies of the interaction of methanol with the S2 state of the Mn4O5Ca cluster of photosystem II.

    Science.gov (United States)

    Oyala, Paul H; Stich, Troy A; Stull, Jamie A; Yu, Fangting; Pecoraro, Vincent L; Britt, R David

    2014-12-23

    The binding of the substrate analogue methanol to the catalytic Mn4CaO5 cluster of the water-oxidizing enzyme photosystem II is known to alter the electronic structure properties of the oxygen-evolving complex without retarding O2-evolution under steady-state illumination conditions. We report the binding mode of (13)C-labeled methanol determined using 9.4 GHz (X-band) hyperfine sublevel-correlation (HYSCORE) and 34 GHz (Q-band) electron spin-echo electron nuclear double resonance (ESE-ENDOR) spectroscopies. These results are compared to analogous experiments on a mixed-valence Mn(III)Mn(IV) complex (2-OH-3,5-Cl2-salpn)2Mn(III)Mn(IV) (salpn = N,N'-bis(3,5-dichlorosalicylidene)-1,3-diamino-2-hydroxypropane) in which methanol ligates to the Mn(III) ion ( Larson et al. (1992) J. Am. Chem. Soc. , 114 , 6263 ). In the mixed-valence Mn(III,IV) complex, the hyperfine coupling to the (13)C of the bound methanol (Aiso = 0.65 MHz, T = 1.25 MHz) is appreciably larger than that observed for (13)C methanol associated with the Mn4CaO5 cluster poised in the S2 state, where only a weak dipolar hyperfine interaction (Aiso = 0.05 MHz, T = 0.27 MHz) is observed. An evaluation of the (13)C hyperfine interaction using the X-ray structure coordinates of the Mn4CaO5 cluster indicates that methanol does not bind as a terminal ligand to any of the manganese ions in the oxygen-evolving complex. We favor methanol binding in place of a water ligand to the Ca(2+) in the Mn4CaO5 cluster or in place of one of the waters that form hydrogen bonds with the oxygen bridges of the cluster.

  9. Monoclonal antibody against brain calmodulin-dependent protein kinase type II detects putative conformational changes induced by Ca/sup 2 +/-calmodulin

    Energy Technology Data Exchange (ETDEWEB)

    LeVine, H. III; Su, J.L.; Sahyoun, N.E.

    1988-08-23

    A mouse monoclonal IgG1 antibody has been generated against the soluble form of the calmodulin-dependent protein kinase type II. This antibody recognizes both the soluble and cytoskeletal forms of the enzyme, requiring Ca/sup 2 +/ for the interaction. Other divalent cations such as Zn/sup 2 +/, Mn/sup 2 +/, Cd/sup 2 +/, Co/sup 2 +/, and Ni/sup 2 +/ will substitute for Ca/sup 2 +/, while Mg/sup 2 +/ and Ba/sup 2 +/ will not. The antibody reacts with both the ..cap alpha..- and ..beta..-subunits on Western blots in a similar Ca/sup 2 +/-dependent fashion but with a lower sensitivity. The affinity of the antibody for the kinase is 0.13 nM determined by displacement of /sup 125/I Bolton-Hunter-labeled kinase with unlabeled enzyme. Calmodulin and antibody reciprocally potentiate each other's interaction with the enzyme. This is illustrated both by direct binding studies and by a decrease of the K/sub m app/ for calmodulin and an increase in the V/sub max/ for the autophosphorylation reaction of the enzyme. The antibody thus appears to recognize and stabilize a conformation of the kinase which favors calmodulin binding although it does not itself activate the kinase in the absence of calmodulin. Since the M/sub r/ 30,000 catalytic fragment of the kinase is not immunoreactive, either the antibody combining site of the kinase must be present in the noncatalytic portion of the protein along with the calmodulin binding site or proteolysis interferes with the putative Ca/sup 2 +/-dependent conformational change. Thus, monoclonal antibodies can be useful tools in elucidating the mechanism by which Ca/sup 2 +/ and calmodulin act on the kinase molecule.

  10. Aberrant calcium/calmodulin-dependent protein kinase II (CaMKII) activity is associated with abnormal dendritic spine morphology in the ATRX mutant mouse brain.

    Science.gov (United States)

    Shioda, Norifumi; Beppu, Hideyuki; Fukuda, Takaichi; Li, En; Kitajima, Isao; Fukunaga, Kohji

    2011-01-05

    In humans, mutations in the gene encoding ATRX, a chromatin remodeling protein of the sucrose-nonfermenting 2 family, cause several mental retardation disorders, including α-thalassemia X-linked mental retardation syndrome. We generated ATRX mutant mice lacking exon 2 (ATRX(ΔE2) mice), a mutation that mimics exon 2 mutations seen in human patients and associated with milder forms of retardation. ATRX(ΔE2) mice exhibited abnormal dendritic spine formation in the medial prefrontal cortex (mPFC). Consistent with other mouse models of mental retardation, ATRX(ΔE2) mice exhibited longer and thinner dendritic spines compared with wild-type mice without changes in spine number. Interestingly, aberrant increased calcium/calmodulin-dependent protein kinase II (CaMKII) activity was observed in the mPFC of ATRX(ΔE2) mice. Increased CaMKII autophosphorylation and activity were associated with increased phosphorylation of the Rac1-guanine nucleotide exchange factors (GEFs) T-cell lymphoma invasion and metastasis 1 (Tiam1) and kalirin-7, known substrates of CaMKII. We confirmed increased phosphorylation of p21-activated kinases (PAKs) in mPFC extracts. Furthermore, reduced protein expression and activity of protein phosphatase 1 (PP1) was evident in the mPFC of ATRX(ΔE2) mice. In cultured cortical neurons, PP1 inhibition by okadaic acid increased CaMKII-dependent Tiam1 and kalirin-7 phosphorylation. Together, our data strongly suggest that aberrant CaMKII activation likely mediates abnormal spine formation in the mPFC. Such morphological changes plus elevated Rac1-GEF/PAK signaling seen in ATRX(ΔE2) mice may contribute to mental retardation syndromes seen in human patients.

  11. A new synthetic library of the Near-Infrared CaII triplet indices. I.Index Definition, Calibration and Relations with stellar atmospheric parameters

    CERN Document Server

    Du, Wei; Zhao, Yong-Heng

    2011-01-01

    Adopting the SPECTRUM package, we have synthesized a set of 2,890 Near-InfraRed (NIR) synthetic spectra with a resolution and wavelength sampling similar to the SDSS and the forthcoming LAMOST spectra. During the synthesis, we have applied the `New grids of ATLAS9 Model Atmosphere' to provide a grid of local thermodynamic equilibrium (LTE) model atmospheres. This synthetic stellar library is composed of 1,350 solor scaled abundance (SSA) and 1,530 non-solar scaled abundance (NSSA) spectra, grounding on which we have defined a new set of NIR CaII triplet indices and an index CaT as the sum of the three. Then, these defined indices have been automatically measured on the synthetic spectra and calibrated with the indices computed on the observational spectra from the INDO-U.S. stellar library. In order to check the effect of alpha-element enhancement on the so-defined CaII indices, we have compared indices measured on the SSA spectra with those on the NSSA ones at the same terns of stellar parameters (Teff, log ...

  12. La trehalosa. Parte II: su formación en diferentes variedades de caña

    OpenAIRE

    Susana Ravelo; Eduardo L. Ramos

    2009-01-01

    Se estudia la presencia de la Trehalosa en los jugos de 10 variedades de caña que son especialmente propensas a acumular mezclas de oligosacáridos en sus jugos luego de ser cortadas. Para ello se usó el soporte cromatográfico conocido como HYDROMAG, y su variante modificada superficialmente, HYDROMAGM, los que permiten el aislamiento del oligosacárido estudiado y la identificación del monosacárido que lo forma, respectivamente. Se complementan los estudios, determinando el peso molecular del ...

  13. KWU-werkersklasdramas in Afrikaans (ca. 1930 - ca. 1950

    Directory of Open Access Journals (Sweden)

    J. L. Coetser

    1999-05-01

    Full Text Available GWU working class theatre in Afrikaans (ca. 1930 - ca. 1950In 1984 Elsabé Brink drew attention to plays, prose and poetry written between 1930 and 1950 in Afrikaans by members of the Garment Workers’ Union (GWU. Scholars such as Stander and Willemse (1992, Van Niekerk (1996 and Van Wyk (1995, 1997 have also referred to GWU plays. Apart from these overviews, GWU plays as such have not yet received the attention they deserve. This article presents a revaluation, initially by providing an overview of their contents, followed by an examination of cultural, economic and political influences. It is argued that - retrospectively - the GWU plays reflected a unique cultural specificity from the framework established by Sitas (1986 for more contemporary working class theatre.

  14. Ca2+ dynamics in zebrafish morphogenesis

    Directory of Open Access Journals (Sweden)

    Yusuke Tsuruwaka

    2017-01-01

    Full Text Available Intracellular calcium ion (Ca2+ signaling is heavily involved in development, as illustrated by the use of a number of Ca2+ indicators. However, continuous Ca2+ patterns during morphogenesis have not yet been studied using fluorescence resonance energy transfer to track the Ca2+ sensor. In the present study, we monitored Ca2+ levels during zebrafish morphogenesis and differentiation with yellow cameleon, YC2.12. Our results show not only clear changes in Ca2+ levels but also continuous Ca2+ patterns at 24 hpf and later periods for the first time. Serial Ca2+dynamics during early pharyngula period (Prim-5-20; 24–33 hpf was successfully observed with cameleon, which have not reported anywhere yet. In fact, high Ca2+ level occurred concurrently with hindbrain development in segmentation and pharyngula periods. Ca2+ patterns in the late gastrula through segmentation periods which were obtained with cameleon, were similar to those obtained previously with other Ca2+sensor. Our results suggested that the use of various Ca2+ sensors may lead to novel findings in studies of Ca2+ dynamics. We hope that these results will prove valuable for further research in Ca2+ signaling.

  15. The other side of cardiac Ca2+ signaling: transcriptional control

    Directory of Open Access Journals (Sweden)

    Alejandro eDomínguez-Rodríquez

    2012-11-01

    Full Text Available Ca2+ is probably the most versatile signal transduction element used by all cell types. In the heart, it is essential to activate cellular contraction in each heartbeat. Nevertheless Ca2+ is not only a key element in excitation-contraction coupling (EC coupling, but it is also a pivotal second messenger in cardiac signal transduction, being able to control processes such as excitability, metabolism, and transcriptional regulation. Regarding the latter, Ca2+ activates Ca2+-dependent transcription factors by a process called excitation-transcription coupling (ET coupling. ET coupling is an integrated process by which the common signaling pathways that regulate EC coupling activate transcription factors. Although ET coupling has been extensively studied in neurons and other cell types, less is known in cardiac muscle. Some hints have been found in studies on the development of cardiac hypertrophy, where two Ca2+-dependent enzymes are key actors: Ca2+/Calmodulin kinase II (CaMKII and phosphatase calcineurin, both of which are activated by the complex Ca2+/ /Calmodulin. The question now is how ET coupling occurs in cardiomyocytes, where intracellular Ca2+ is continuously oscillating. In this focused review, we will draw attention to location of Ca2+ signaling: intranuclear ([Ca2+]n or cytoplasmic ([Ca2+]c, and the specific ionic channels involved in the activation of cardiac ET coupling. Specifically, we will highlight the role of the 1,4,5 inositol triphosphate receptors (IP3Rs in the elevation of [Ca2+]n levels, which are important to locally activate CaMKII, and the role of transient receptor potential channels canonical (TRPCs in [Ca2+]c, needed to activate calcineurin.

  16. Structure of the CaMKIIdelta/calmodulin complex reveals the molecular mechanism of CaMKII kinase activation.

    Directory of Open Access Journals (Sweden)

    Peter Rellos

    Full Text Available UNLABELLED: Long-term potentiation (LTP, a long-lasting enhancement in communication between neurons, is considered to be the major cellular mechanism underlying learning and memory. LTP triggers high-frequency calcium pulses that result in the activation of Calcium/Calmodulin (CaM-dependent kinase II (CaMKII. CaMKII acts as a molecular switch because it remains active for a long time after the return to basal calcium levels, which is a unique property required for CaMKII function. Here we describe the crystal structure of the human CaMKIIdelta/Ca2+/CaM complex, structures of all four human CaMKII catalytic domains in their autoinhibited states, as well as structures of human CaMKII oligomerization domains in their tetradecameric and physiological dodecameric states. All four autoinhibited human CaMKIIs were monomeric in the determined crystal structures but associated weakly in solution. In the CaMKIIdelta/Ca2+/CaM complex, the inhibitory region adopted an extended conformation and interacted with an adjacent catalytic domain positioning T287 into the active site of the interacting protomer. Comparisons with autoinhibited CaMKII structures showed that binding of calmodulin leads to the rearrangement of residues in the active site to a conformation suitable for ATP binding and to the closure of the binding groove for the autoinhibitory helix by helix alphaD. The structural data, together with biophysical interaction studies, reveals the mechanism of CaMKII activation by calmodulin and explains many of the unique regulatory properties of these two essential signaling molecules. ENHANCED VERSION: This article can also be viewed as an enhanced version in which the text of the article is integrated with interactive 3-D representations and animated transitions. Please note that a web plugin is required to access this enhanced functionality. Instructions for the installation and use of the Web plugin are available in Text S1.

  17. Lattice Dynamics of fcc Ca

    DEFF Research Database (Denmark)

    Stassis, C.; Zaretsky, J.; Misemer, D. K.;;

    1983-01-01

    to the propagation of elastic waves. The frequencies of the T1[ξξ0] branch for ξ between approximately 0.5 and 0.8 are slightly above the velocity-of-sound line determined from the low-frequency measurements. Since a similar effect has been observed in FCC Yb, it is natural to assume that the anomalous dispersion......A large single crystal of FCC Ca was grown and was used to study the lattice dynamics of this divalent metal by coherent inelastic neutron scattering. The phonon dispersion curves were measured, at room temperature, along the [ξ00], [ξξ0], [ξξξ], and [0ξ1] symmetry directions. The dispersion curves...... bear a striking resemblance to those of FCC Yb, which is also a divalent metal with an electronic band structure similar to that of Ca. In particular, the shear moduli c44 and (c11-c 12)/2 differ by a factor of 3.4, which implies that FCC Ca (like FCC Yb) is very anisotropic with regard...

  18. Fine tuning of cytosolic Ca 2+ oscillations

    Science.gov (United States)

    Dupont, Geneviève; Combettes, Laurent

    2016-01-01

    Ca 2+ oscillations, a widespread mode of cell signaling, were reported in non-excitable cells for the first time more than 25 years ago. Their fundamental mechanism, based on the periodic Ca 2+ exchange between the endoplasmic reticulum and the cytoplasm, has been well characterized. However, how the kinetics of cytosolic Ca 2+ changes are related to the extent of a physiological response remains poorly understood. Here, we review data suggesting that the downstream targets of Ca 2+ are controlled not only by the frequency of Ca 2+ oscillations but also by the detailed characteristics of the oscillations, such as their duration, shape, or baseline level. Involvement of non-endoplasmic reticulum Ca 2+ stores, mainly mitochondria and the extracellular medium, participates in this fine tuning of Ca 2+ oscillations. The main characteristics of the Ca 2+ exchange fluxes with these compartments are also reviewed. PMID:27630768

  19. [Effect of polycarbophil Ca on IBS].

    Science.gov (United States)

    Mine, Tetsuya

    2006-08-01

    In this chapter, I mentioned the effect of polycarbophil Ca on IBS. IBS is classified into 3 types; diarrhea type, constipation type and combined type. Polycarbophil Ca is effective for all types of IBS.

  20. Barnacle muscle: Ca2+, activation and mechanics.

    Science.gov (United States)

    Ashley, C C; Griffiths, P J; Lea, T J; Mulligan, I P; Palmer, R E; Simnett, S J

    1993-01-01

    In this review, aspects of the ways in which Ca2+ is transported and regulated within muscle cells have been considered, with particular reference to crustacean muscle fibres. The large size of these fibres permits easy access to the internal environment of the cell, allowing it to be altered by microinjection or microperfusion. At rest, Ca2+ is not in equilibrium across the cell membrane, it enters the cell down a steep electrochemical gradient. The free [Ca2+] at rest is maintained at a value close to 200 nM by a combination of internal buffering systems, mainly the SR, mitochondria, and the fixed and diffusible Ca(2+)-binding proteins, as well as by an energy-dependent extrusion system operating across the external cell membrane. This system relies upon the inward movement of Na+ down its own electrochemical gradient to provide the energy for the extrusion of Ca2+ ions. As a result of electrical excitation, voltage-sensitive channels for Ca2+ are activated and permit Ca2+ to enter the cell more rapidly than at rest. It has been possible to determine both the amount of Ca2+ entering by this step, and what part this externally derived Ca2+ plays in the development of force as well as in the free Ca2+ change. The latter can be determined directly by Ca(2+)-sensitive indicators introduced into the cell sarcoplasm. A combination of techniques, allowing both the total and free Ca2+ changes to be assessed during electrical excitation, has provided valuable information as to how muscle cells buffer their Ca2+ in order to regulate the extent of the change in the free Ca2+ concentration. The data indicate that the entering Ca2+ can only make a small direct contribution to the force developed by the cell. The implication here is that the major source of Ca2+ for contraction must be derived from the internal Ca2+ storage sites within the SR system, a view reinforced by caged Ca2+ methods. The ability to measure the free Ca2+ concentration changes within a single cell during

  1. CA-CA互操作研究%Research of CA-CA Interoperability

    Institute of Scientific and Technical Information of China (English)

    沈士根; 叶培松; 陈宝明

    2005-01-01

    文章介绍了国际上CA-CA之间实现互操作的信任模式,然后根据中国目前的PKI实际情况,提出了以桥CA为全局模式,局部可采用严格层次信任模式来实现各CA之间的互操作.

  2. Altered network timing in the CA3-CA1 circuit of hippocampal slices from aged mice.

    Directory of Open Access Journals (Sweden)

    Daniel J Kanak

    Full Text Available Network patterns are believed to provide unique temporal contexts for coordinating neuronal activity within and across different regions of the brain. Some of the characteristics of network patterns modeled in vitro are altered in the CA3 or CA1 subregions of hippocampal slices from aged mice. CA3-CA1 network interactions have not been examined previously. We used slices from aged and adult mice to model spontaneous sharp wave ripples and carbachol-induced gamma oscillations, and compared measures of CA3-CA1 network timing between age groups. Coherent sharp wave ripples and gamma oscillations were evident in the CA3-CA1 circuit in both age groups, but the relative timing of activity in CA1 stratum pyramidale was delayed in the aged. In another sample of aged slices, evoked Schaffer collateral responses were attenuated in CA3 (antidromic spike amplitude and CA1 (orthodromic field EPSP slope. However, the amplitude and timing of spontaneous sharp waves recorded in CA1 stratum radiatum were similar to adults. In both age groups unit activity recorded juxtacellularly from unidentified neurons in CA1 stratum pyramidale and stratum oriens was temporally modulated by CA3 ripples. However, aged neurons exhibited reduced spike probability during the early cycles of the CA3 ripple oscillation. These findings suggest that aging disrupts the coordination of patterned activity in the CA3-CA1 circuit.

  3. An inhibitory effect of extracellular Ca2+ on Ca2+-dependent exocytosis.

    Directory of Open Access Journals (Sweden)

    Wei Xiong

    Full Text Available AIM: Neurotransmitter release is elicited by an elevation of intracellular Ca(2+ concentration ([Ca(2+](i. The action potential triggers Ca(2+ influx through Ca(2+ channels which causes local changes of [Ca(2+](i for vesicle release. However, any direct role of extracellular Ca(2+ (besides Ca(2+ influx on Ca(2+-dependent exocytosis remains elusive. Here we set out to investigate this possibility on rat dorsal root ganglion (DRG neurons and chromaffin cells, widely used models for studying vesicle exocytosis. RESULTS: Using photolysis of caged Ca(2+ and caffeine-induced release of stored Ca(2+, we found that extracellular Ca(2+ inhibited exocytosis following moderate [Ca(2+](i rises (2-3 µM. The IC(50 for extracellular Ca(2+ inhibition of exocytosis (ECIE was 1.38 mM and a physiological reduction (∼30% of extracellular Ca(2+ concentration ([Ca(2+](o significantly increased the evoked exocytosis. At the single vesicle level, quantal size and release frequency were also altered by physiological [Ca(2+](o. The calcimimetics Mg(2+, Cd(2+, G418, and neomycin all inhibited exocytosis. The extracellular Ca(2+-sensing receptor (CaSR was not involved because specific drugs and knockdown of CaSR in DRG neurons did not affect ECIE. CONCLUSION/SIGNIFICANCE: As an extension of the classic Ca(2+ hypothesis of synaptic release, physiological levels of extracellular Ca(2+ play dual roles in evoked exocytosis by providing a source of Ca(2+ influx, and by directly regulating quantal size and release probability in neuronal cells.

  4. Effects of La(III) and Ca(II) on isolated Carassius auratus liver mitochondria: heat production and mitochondrial permeability transition.

    Science.gov (United States)

    Wu, Man; Gao, Jia-Ling; Sun, Mei-Xiang; Zhang, Ye-Zhong; Liu, Yi; Dai, Jie

    2015-02-01

    The effects of lanthanum and calcium on heat production of mitochondria isolated from Carassius auratus liver were investigated by microcalorimetry, and their effects on mitochondrial swelling and membrane potential (Δψ) were determined by spectroscopic methods. La(3+) showed only inhibitory action on mitochondrial energy turnover with inhibition concentration of 50 % (IC50) being 71.2 μmol L(-1). Similarly, Ca(2+) restrained the heat production of mitochondria, and the IC50 of Ca(2+) was much higher than that of La(3+). In the spectroscopic experiments, La(3+) and Ca(2+) induced fish liver mitochondrial swelling and decreased membrane potential (Δψ), and the induction ability of La(3+) was stronger than that of Ca(2+). It is concluded that the effects of La(3+) and Ca(2+) on fish liver mitochondria differ, and La represents toxic action rather than Ca analogy.

  5. X-ray Damage to the Mn4Ca Complex in Single Crystals ofPhotosystem II: A Case Study for Metalloprotein Crystallography

    Energy Technology Data Exchange (ETDEWEB)

    Yano, Junko; Kern, Jan; Irrgang, Klaus-Dieter; Latimer, Matthew; Bergmann, Uwe; Glatzel, Pieter; Pushkar, Yulia; Biesiadka, Jacek; Loll,Bernhard; Sauer, Kenneth; Messinger, Johannes; Zouni, Athina; Yachandra,Vittal K.

    2005-06-21

    X-ray absorption spectroscopy was used to measure the damage caused by exposure to X-rays to the Mn4Ca active site in single crystals of photosystem II, as a function of dose and energy of X-rays, temperature, and time. These studies reveal that the conditions used for structure determination by X-ray crystallography cause serious damage specifically to the metal-site structure. The X-ray absorption spectra show that the structure changes from one that is characteristic of a high-valent Mn4(III2,IV2) oxo-bridged Mn4Ca cluster, to that of Mn(II) in aqueous solution. This damage to the metal site occurs at a dose that is more than an order of magnitude lower than that resulting in loss of diffractivity, and commonly considered safe for protein crystallography. These results establish the first quantitative X-ray dose parameters applicable to redox-active metallo-proteins. This case study shows that a careful evaluation of the structural intactness of the active sites by spectroscopic techniques can validate structures derived from crystallography, and it can be a valuable complementary method before structure-function correlations of metallo-proteins can be made on the basis of high resolution X-ray crystal structures.

  6. X-ray damage to the Mn4Ca complex in single crystals of photosystem II: a case study for metalloprotein crystallography.

    Science.gov (United States)

    Yano, Junko; Kern, Jan; Irrgang, Klaus-Dieter; Latimer, Matthew J; Bergmann, Uwe; Glatzel, Pieter; Pushkar, Yulia; Biesiadka, Jacek; Loll, Bernhard; Sauer, Kenneth; Messinger, Johannes; Zouni, Athina; Yachandra, Vittal K

    2005-08-23

    X-ray absorption spectroscopy was used to measure the damage caused by exposure to x-rays to the Mn(4)Ca active site in single crystals of photosystem II as a function of dose and energy of x-rays, temperature, and time. These studies reveal that the conditions used for structure determination by x-ray crystallography cause serious damage specifically to the metal-site structure. The x-ray absorption spectra show that the structure changes from one that is characteristic of a high-valent Mn(4)(III(2),IV(2)) oxo-bridged Mn(4)Ca cluster to that of Mn(II) in aqueous solution. This damage to the metal site occurs at a dose that is more than one order of magnitude lower than the dose that results in loss of diffractivity and is commonly considered safe for protein crystallography. These results establish quantitative x-ray dose parameters that are applicable to redox-active metalloproteins. This case study shows that a careful evaluation of the structural intactness of the active site(s) by spectroscopic techniques can validate structures derived from crystallography and that it can be a valuable complementary method before structure-function correlations of metalloproteins can be made on the basis of high-resolution x-ray crystal structures.

  7. On the long-term correlation between the flux in the Ca II H & K and Halpha lines for FGK stars

    CERN Document Server

    da Silva, J Gomes; Boisse, I; Dumusque, X; Lovis, C

    2013-01-01

    The re-emission in the cores of the Ca II H & K and H$\\alpha$ lines, are well known proxies of stellar activity. However, these activity indices probe different activity phenomena, the first being more sensitive to plage variation, while the other one being more sensitive to filaments. In this paper we study the long-term correlation between $\\log R'_{HK}$ and $\\log I_{H\\alpha}$, two indices based on the Ca II H & K and H$\\alpha$ lines respectively, for a sample of 271 FGK stars using measurements obtained over a $\\sim$9 year time span. Because stellar activity is one of the main obstacles to the detection of low-mass and long-period planets, understanding further this activity index correlation can give us some hints about the optimal target to focus on, and ways to correct for these activity effects. We found a great variety of long-term correlations between $\\log R'_{HK}$ and $\\log I_{H\\alpha}$. Around 20% of our sample has strong positive correlation between the indices while about 3% show strong ...

  8. 46 CFR 7.130 - Point Conception, CA to Point Sur, CA.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Point Conception, CA to Point Sur, CA. 7.130 Section 7.130 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY PROCEDURES APPLICABLE TO THE PUBLIC BOUNDARY LINES Pacific Coast § 7.130 Point Conception, CA to Point Sur, CA. (a) A line drawn from...

  9. Testing coral paleothermometers (B/Ca, Mg/Ca, Sr/Ca, U/Ca andδ18O) under impacts of large riverine runoff

    Institute of Scientific and Technical Information of China (English)

    CHEN Tianran; YU Kefu; ZHAO Jianxin; YAN Hongqiang; SONG Yinxian; FENG Yuexing; CHEN Tegu

    2015-01-01

    Sea surface temperature (SST) proxies including B/Ca, Mg/Ca, Sr/Ca, U/Ca andδ18O were analyzed in the skeleton of aPorites coral collected from the Zhujiang River (Pearl River) Estuary (ZRE). These geochemical proxies are influenced by river runoff and this area of the northern South China Sea is strongly affected by seasonal freshwater floods. We assessed the robustness of each SST proxy through comparison with the local instrumental SST. Coral Sr/Ca shows the highest correlation with SST variations (r2=0.59), suggesting Sr/Ca is the most robust SST proxy. In contrast, coralδ18O (r2=0.46), B/Ca (r2=0.43) and U/Ca (r2=0.41) ratios were only moderately correlated with SST variations, suggesting that they are disturbed by some other factors in addition to SST. The poor correlation (r2=0.27) between SST and Mg/Ca indicates that Mg/Ca in coral skeletons is not a simple function of SST variations. This may ultimately limit the use of Mg/Ca as a coral paleothermometer.

  10. Multiple Ca2+ sensors in secretion

    DEFF Research Database (Denmark)

    Walter, Alexander M; Groffen, Alexander J; Sørensen, Jakob Balslev;

    2011-01-01

    Regulated neurotransmitter secretion depends on Ca(2+) sensors, C2 domain proteins that associate with phospholipids and soluble N-ethylmaleimide-sensitive fusion attachment protein receptor (SNARE) complexes to trigger release upon Ca(2+) binding. Ca(2+) sensors are thought to prevent spontaneous...... fusion at rest (clamping) and to promote fusion upon Ca(2+) activation. At least eight, often coexpressed, Ca(2+) sensors have been identified in mammals. Accumulating evidence suggests that multiple Ca(2+) sensors interact, rather than work autonomously, to produce the complex secretory response...... observed in neurons and secretory cells. In this review, we present several working models to describe how different sensors might be arranged to mediate synchronous, asynchronous and spontaneous neurotransmitter release. We discuss the scenario that different Ca(2+) sensors typically act on one shared...

  11. On the mechanism of synaptic depression induced by CaMKIIN, an endogenous inhibitor of CaMKII.

    Directory of Open Access Journals (Sweden)

    Camilo Gouet

    Full Text Available Activity-dependent synaptic plasticity underlies, at least in part, learning and memory processes. NMDA receptor (NMDAR-dependent long-term potentiation (LTP is a major synaptic plasticity model. During LTP induction, Ca(2+/calmodulin-dependent protein kinase II (CaMKII is activated, autophosphorylated and persistently translocated to the postsynaptic density, where it binds to the NMDAR. If any of these steps is inhibited, LTP is disrupted. The endogenous CaMKII inhibitor proteins CaMKIINα,β are rapidly upregulated in specific brain regions after learning. We recently showed that transient application of peptides derived from CaMKIINα (CN peptides persistently depresses synaptic strength and reverses LTP saturation, as it allows further LTP induction in previously saturated pathways. The treatment disrupts basal CaMKII-NMDAR interaction and decreases bound CaMKII fraction in spines. To unravel CaMKIIN function and to further understand CaMKII role in synaptic strength maintenance, here we more deeply investigated the mechanism of synaptic depression induced by CN peptides (CN-depression in rat hippocampal slices. We showed that CN-depression does not require glutamatergic synaptic activity or Ca(2+ signaling, thus discarding unspecific triggering of activity-dependent long-term depression (LTD in slices. Moreover, occlusion experiments revealed that CN-depression and NMDAR-LTD have different expression mechanisms. We showed that CN-depression does not involve complex metabolic pathways including protein synthesis or proteasome-mediated degradation. Remarkably, CN-depression cannot be resolved in neonate rats, for which CaMKII is mostly cytosolic and virtually absent at the postsynaptic densities. Overall, our results support a direct effect of CN peptides on synaptic CaMKII-NMDAR binding and suggest that CaMKIINα,β could be critical plasticity-related proteins that may operate as cell-wide homeostatic regulators preventing saturation of

  12. Fourier transform spectrometer observations of solar carbon monoxide. II - Simultaneous cospatial measurements of the fundamental and first-overtone bands, and Ca II K, in quiet and active regions

    Science.gov (United States)

    Ayres, T. R.; Testerman, L.; Brault, J. W.

    1986-01-01

    Fourier transform spectrometry has yielded simultaneous cospatial measurements of important diagnostics of thermal structure in the high solar photosphere and low chromosphere. It is noted that the anomalous behavior of the fundamental bands of CO in quiet areas near the limb is accentuated in an active region plage observed close to the limb. The difference between the core temperatures of the CO fundamental bands in a plage and a nearby quiet region at the limb is larger than the corresponding brightness temperature differences in the inner wings of the Ca II line measured in a quiet region and several plages closer to the disk center. Numerical simulations indicate that the disparate behavior of the CO bands with respect to Ca II K cannot be reconciled with existing single component thermal structure models; a two-component atmosphere is required.

  13. The Expression of CaN and CaMK is Associated with Lipogenesis in the Muscle of Chicken

    Institute of Scientific and Technical Information of China (English)

    Ye YANG; Jiao SONG; Ruiqi FUl; Yanfa SUN; Jie WEN

    2015-01-01

    IntramuscuIar fat (IMF) content in chickens significantIy contributes to meat quality. The maln objective of this study was to assess the expression of calcineurin (CaN) and Ca2+/calmoduIin-dependent protein kinase (CaMK) in Iipogene-sis in chicken muscIe. The chickens were sIaughtered and sampIed at the ages of 4, 8, and 16 weeks, respectiveIy. IMF content and the expression of CaN subunits and CaMK isoforms were measured in thigh muscIe tissue. The resuIts showed that the IMF contents were higher in chickens at the age of 16 weeks compared with those in chickens at the ages of 4 and 8 weeks (P<0.05). The expression IeveIs of fatty acid synthase (FAS) and fatty acid transIocase CD36 (FAT/CD36) mRNA in 16-week-oId chickens were al significantIy up-reguIated compared with those in 4-week-oId chickens (P<0.05). The mRNA IeveIs of CaNB and CaMK IV in 16-week-oId chickens were significantIy Iower than those in 4-week-oId chickens (P<0.05). But the CaMK II mRNA IeveIs in 16-week-oId chickens were significantIy higher than those in 4-week-oId chickens (P<0.05). To investigate the roIes of CaMK and CaN in adipogenesis, SV ceI s were incubated in standard adipogenesis medium for 24 h and treated with specific inhibitor of CaMK and CaN. The ex-pressions of CCAAT/enhancer binding protein β(C/EBPβ), steroI reguIatory eIement-binding protein 1 (SREBP1) and peroxisome proIiferation-activated receptor γ(PPARγ) were dramatical y enhanced by CsA and CaN inhibitor (P<0.05). KN93, a CaMK II inhibitor, dramatical y repressed the expression of those Iipogenic genes (P<0.05). al the resuIts above indicated that CaN and CaMK had different effects on adipogenesis in the muscIe of chickens.

  14. Ca2+ influx through L-type Ca2+ channels and Ca2+-induced Ca2+ release regulate cAMP accumulation and Epac1-dependent ERK 1/2 activation in INS-1 cells.

    Science.gov (United States)

    Pratt, Evan P S; Salyer, Amy E; Guerra, Marcy L; Hockerman, Gregory H

    2016-01-05

    We previously reported that INS-1 cells expressing the intracellular II-III loop of the L-type Ca(2+) channel Cav1.2 (Cav1.2/II-III cells) are deficient in Ca(2+)-induced Ca(2+) release (CICR). Here we show that glucose-stimulated ERK 1/2 phosphorylation (GSEP) is slowed and reduced in Cav1.2/II-III cells compared to INS-1 cells. This parallels a decrease in glucose-stimulated cAMP accumulation (GS-cAMP) in Cav1.2/II-III cells. Influx of Ca(2+) via L-type Ca(2+) channels and CICR play roles in both GSEP and GS-cAMP in INS-1 cells since both are inhibited by nicardipine or ryanodine. Further, the Epac1-selective inhibitor CE3F4 abolishes glucose-stimulated ERK activation in INS-1 cells, as measured using the FRET-based sensor EKAR. The non-selective Epac antagonist ESI-09 but not the Epac2-selective antagonist ESI-05 nor the PKA antagonist Rp-cAMPs inhibits GSEP in both INS-1 and Cav1.2/II-III cells. We conclude that L-type Ca(2+) channel-dependent cAMP accumulation, that's amplified by CICR, activates Epac1 and drives GSEP in INS-1 cells.

  15. Ca(II) doped β-In2S3 hierarchical structures for photocatalytic hydrogen generation and organic dye degradation under visible light irradiation.

    Science.gov (United States)

    Yang, Shuang; Xu, Cheng-Yan; Zhang, Bao-You; Yang, Li; Hu, Sheng-Peng; Zhen, Liang

    2017-04-01

    Hierarchical structures assembled by two-dimensional (2D) nanosheets could inherit the characteristics of nanosheets and acquire additional advantages from the unique secondary architectures, which would have important influences on the photocatalytic properties of semiconductor nanomaterials. In this work, we successfully synthesized Ca(II) doped β-In2S3 hierarchical structures stacked by thin nanosheets by a simple solution chemical process. The effects of reaction temperature and Ca(2+) concentration on the size and morphology of the products were systematically investigated. The photocatalytic applications of the β-In2S3 hierarchical structures were evaluated for hydrogen production and degradation of Rhodamine B (RhB) under visible light irradiation (λ>420nm). The β-In2S3 hierarchical structures showed promising activity towards photocatalytic hydrogen production (145.0μmolg(-1)h(-1)) and RhB solution (1×10(-5)M) was completely degraded within 100min under visible light irradiation.

  16. Meiosis, egg activation, and nuclear envelope breakdown are differentially reliant on Ca2+, whereas germinal vesicle breakdown is Ca2+ independent in the mouse oocyte

    Science.gov (United States)

    Tombes, R. M.; Simerly, C.; Borisy, G. G.; Schatten, G.

    1992-01-01

    During early development, intracellular Ca2+ mobilization is not only essential for fertilization, but has also been implicated during other meiotic and mitotic events, such as germinal vesicle breakdown (GVBD) and nuclear envelope breakdown (NEBD). In this study, the roles of intracellular and extracellular Ca2+ were examined during meiotic maturation and reinitiation at parthenogenetic activation and during first mitosis in a single species using the same methodologies. Cumulus-free metaphase II mouse oocytes immediately resumed anaphase upon the induction of a large, transient Ca2+ elevation. This resumption of meiosis and associated events, such as cortical granule discharge, were not sensitive to extracellular Ca2+ removal, but were blocked by intracellular Ca2+ chelators. In contrast, meiosis I was dependent on external Ca2+; in its absence, the formation and function of the first meiotic spindle was delayed, the first polar body did not form and an interphase-like state was induced. GVBD was not dependent on external Ca2+ and showed no associated Ca2+ changes. NEBD at first mitosis in fertilized eggs, on the other hand, was frequently, but not always associated with a brief Ca2+ transient and was dependent on Ca2+ mobilization. We conclude that GVBD is Ca2+ independent, but that the dependence of NEBD on Ca2+ suggests regulation by more than one pathway. As cells develop from Ca(2+)-independent germinal vesicle oocytes to internal Ca(2+)-dependent pronuclear eggs, internal Ca2+ pools increase by approximately fourfold.

  17. Influence of NaCl-CaCl2 on Decomposing REPO4 with CaO

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The influence of NaCl-CaCl2 on thermal decomposition of REPO4 (RE: Ce, La, Nd, Th) with CaO was studied.The heat decomposing process of REPO4 was tested with TG-DTA experiments.The results showed that the decomposition temperature of REPO4 with CaO was reduced because of adding NaCl-CaCl2 mixture (NaCl:CaCl2=1:1).The influence of the addition of NaCl-CaCl2, roasting temperature and roasting time on decomposition ratio of REPO4 with CaO was studied.The results showed that the decomposition ratio of REPO4with CaO was 79% when the addition percentage of NaCl-CaCl2 was 10%, the roasting temperature was 750℃, and the roasting time was 1 h.

  18. Involvement of Ca2+/CaM in the signal transduction of acetylcholine regulating stomatal movement

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    It has been known that the neurotransmitter acetylcholine (ACh) also exists in plants and is able to regulate the movement of stomata. In another aspect, Ca2+/CaM as the second messengers have a critical role of signal transduction in stomatal guard-cell. Here we showed that Ca2+/CaM were also involved in theACh regulated stomatal movement. In the medium containing Ca2+, the Ca2+ channel blockers (NIF and Ver) and CaM inhibitors (TFP and W7) could neutralize the ACh induced stomatal opening, however, they are ineffective in the medium containing K+. Those results indicated that Ca2+/CaM were involved in the signal transduction pathway of ACh regulating stomatal movement.

  19. Ca2+ cycling in heart cells from ground squirrels: adaptive strategies for intracellular Ca2+ homeostasis.

    Directory of Open Access Journals (Sweden)

    Xiao-Chen Li

    Full Text Available Heart tissues from hibernating mammals, such as ground squirrels, are able to endure hypothermia, hypoxia and other extreme insulting factors that are fatal for human and nonhibernating mammals. This study was designed to understand adaptive mechanisms involved in intracellular Ca(2+ homeostasis in cardiomyocytes from the mammalian hibernator, ground squirrel, compared to rat. Electrophysiological and confocal imaging experiments showed that the voltage-dependence of L-type Ca(2+ current (I(Ca was shifted to higher potentials in ventricular myocytes from ground squirrels vs. rats. The elevated threshold of I(Ca did not compromise the Ca(2+-induced Ca(2+ release, because a higher depolarization rate and a longer duration of action potential compensated the voltage shift of I(Ca. Both the caffeine-sensitive and caffeine-resistant components of cytosolic Ca(2+ removal were more rapid in ground squirrels. Ca(2+ sparks in ground squirrels exhibited larger amplitude/size and much lower frequency than in rats. Due to the high I(Ca threshold, low SR Ca(2+ leak and rapid cytosolic Ca(2+ clearance, heart cells from ground squirrels exhibited better capability in maintaining intracellular Ca(2+ homeostasis than those from rats and other nonhibernating mammals. These findings not only reveal adaptive mechanisms of hibernation, but also provide novel strategies against Ca(2+ overload-related heart diseases.

  20. Participation of glutamate-333 of the D1 polypeptide in the ligation of the Mn₄CaO₅ cluster in photosystem II.

    Science.gov (United States)

    Service, Rachel J; Yano, Junko; Dilbeck, Preston L; Burnap, Robert L; Hillier, Warwick; Debus, Richard J

    2013-11-26

    In the 1.9 Å structural model of photosystem II (PDB: 3ARC), the amino acid residue Glu333 of the D1 polypeptide coordinates to the oxygen-evolving Mn₄CaO₅ cluster. This residue appears to be highly significant in that it bridges the two Mn ions (Mn(B3) and the "dangling" Mn(A4)) that are also bridged by the oxygen atom O5. This oxygen atom has been proposed to be derived from one of two substrate water molecules and to become incorporated into the product dioxygen molecule during the final step in the catalytic cycle. In addition, the backbone nitrogen of D1-Glu333 interacts directly with a nearby Cl⁻ atom. To further explore the influence of this structurally unique residue on the properties of the Mn₄CaO₅ cluster, the D1-E333Q mutant of the cyanobacterium Synechocystis sp. PCC 6803 was characterized with a variety of biophysical and spectroscopic methods, including polarography, EPR, X-ray absorption, and FTIR difference spectroscopy. The kinetics of oxygen release in the mutant were essentially unchanged from those in wild-type. In addition, the oxygen flash yields exhibited normal period-four oscillations having normal S state parameters, although the yields were lower, indicative of the mutant's lower steady-state dioxygen evolution rate of approximately 30% compared to that of the wild-type. The S₁ state Mn-XANES and Mn-EXAFS and S₂ state multiline EPR signals of purified D1-E333Q PSII core complexes closely resembled those of wild-type, aside from having lower amplitudes. The S(n+1)-minus-S(n) FTIR difference spectra showed only minor alterations to the carbonyl, amide, and carboxylate stretching regions. However, the mutation eliminated a negative peak at 3663 cm⁻¹ in the weakly H-bonding O-H stretching region of the S₂-minus-S₁ FTIR difference spectrum and caused an approximately 9 cm⁻¹ downshift of the negative feature in this region of the S₁-minus-S₀ FTIR difference spectrum. We conclude that fully functional Mn₄Ca

  1. Caffeine-induced Ca2+ transients and exocytosis in Paramecium cells. A correlated Ca2+ imaging and quenched-flow/freeze-fracture analysis.

    Science.gov (United States)

    Klauke, N; Plattner, H

    1998-01-01

    Caffeine causes a [Ca2+]i increase in the cortex of Paramecium cells, followed by spillover with considerable attenuation, into central cell regions. From [Ca2+]resti approximately 50 to 80 nm, [Ca2+]acti rises within /=2 sec. Chelation of Ca2+o considerably attenuated [Ca2+]i increase. Therefore, caffeine may primarily mobilize cortical Ca2+ pools, superimposed by Ca2+ influx and spillover (particularly in tl cells with empty trichocyst docking sites). In nd cells, caffeine caused trichocyst contents to decondense internally (Ca2+-dependent stretching, normally occurring only after membrane fusion). With 7S cells this usually occurred only to a small extent, but with increasing frequency as [Ca2+]i signals were reduced by [Ca2+]o chelation. In this case, quenched-flow and ultrathin section or freeze-fracture analysis revealed dispersal of membrane components (without fusion) subsequent to internal contents decondensation, opposite to normal membrane fusion when a full [Ca2+]i signal was generated by caffeine stimulation (with Ca2+i and Ca2+o available). We conclude the following. (i) Caffeine can mobilize Ca2+ from cortical stores independent of the presence of Ca2+o. (ii) To yield adequate signals for normal exocytosis, Ca2+ release and Ca2+ influx both have to occur during caffeine stimulation. (iii) Insufficient [Ca2+]i increase entails caffeine-mediated access of Ca2+ to the secretory contents, thus causing their decondensation before membrane fusion can occur. (iv) Trichocyst decondensation in turn gives a signal for an unusual dissociation of docking/fusion components at the cell membrane. These observations imply different threshold [Ca2+]i-values for membrane fusion and contents discharge.

  2. γCaMKII shuttles Ca²⁺/CaM to the nucleus to trigger CREB phosphorylation and gene expression.

    Science.gov (United States)

    Ma, Huan; Groth, Rachel D; Cohen, Samuel M; Emery, John F; Li, Boxing; Hoedt, Esthelle; Zhang, Guoan; Neubert, Thomas A; Tsien, Richard W

    2014-10-09

    Activity-dependent CREB phosphorylation and gene expression are critical for long-term neuronal plasticity. Local signaling at CaV1 channels triggers these events, but how information is relayed onward to the nucleus remains unclear. Here, we report a mechanism that mediates long-distance communication within cells: a shuttle that transports Ca(2+)/calmodulin from the surface membrane to the nucleus. We show that the shuttle protein is γCaMKII, its phosphorylation at Thr287 by βCaMKII protects the Ca(2+)/CaM signal, and CaN triggers its nuclear translocation. Both βCaMKII and CaN act in close proximity to CaV1 channels, supporting their dominance, whereas γCaMKII operates as a carrier, not as a kinase. Upon arrival within the nucleus, Ca(2+)/CaM activates CaMKK and its substrate CaMKIV, the CREB kinase. This mechanism resolves long-standing puzzles about CaM/CaMK-dependent signaling to the nucleus. The significance of the mechanism is emphasized by dysregulation of CaV1, γCaMKII, βCaMKII, and CaN in multiple neuropsychiatric disorders.

  3. Dissection of local Ca(2+) signals inside cytosol by ER-targeted Ca(2+) indicator.

    Science.gov (United States)

    Niwa, Fumihiro; Sakuragi, Shigeo; Kobayashi, Ayana; Takagi, Shin; Oda, Yoichi; Bannai, Hiroko; Mikoshiba, Katsuhiko

    2016-10-07

    Calcium (Ca(2+)) is a versatile intracellular second messenger that operates in various signaling pathways leading to multiple biological outputs. The diversity of spatiotemporal patterns of Ca(2+) signals, generated by the coordination of Ca(2+) influx from the extracellular space and Ca(2+) release from the intracellular Ca(2+) store the endoplasmic reticulum (ER), is considered to underlie the diversity of biological outputs caused by a single signaling molecule. However, such Ca(2+) signaling diversity has not been well described because of technical limitations. Here, we describe a new method to report Ca(2+) signals at subcellular resolution. We report that OER-GCaMP6f, a genetically encoded Ca(2+) indicator (GECI) targeted to the outer ER membrane, can monitor Ca(2+) release from the ER at higher spatiotemporal resolution than conventional GCaMP6f. OER-GCaMP6f was used for in vivo Ca(2+) imaging of C. elegans. We also found that the spontaneous Ca(2+) elevation in cultured astrocytes reported by OER-GCaMP6f showed a distinct spatiotemporal pattern from that monitored by plasma membrane-targeted GCaMP6f (Lck-GCaMP6f); less frequent Ca(2+) signal was detected by OER-GCaMP6f, in spite of the fact that Ca(2+) release from the ER plays important roles in astrocytes. These findings suggest that targeting of GECIs to the ER outer membrane enables sensitive detection of Ca(2+) release from the ER at subcellular resolution, avoiding the diffusion of GECI and Ca(2+). Our results indicate that Ca(2+) imaging with OER-GCaMP6f in combination with Lck-GCaMP6f can contribute to describing the diversity of Ca(2+) signals, by enabling dissection of Ca(2+) signals at subcellular resolution.

  4. Skeletal muscle Ca(2+)-independent kinase activity increases during either hypertrophy or running

    Science.gov (United States)

    Fluck, M.; Waxham, M. N.; Hamilton, M. T.; Booth, F. W.

    2000-01-01

    Spikes in free Ca(2+) initiate contractions in skeletal muscle cells, but whether and how they might signal to transcription factors in skeletal muscles of living animals is unknown. Since previous studies in non-muscle cells have shown that serum response factor (SRF) protein, a transcription factor, is phosphorylated rapidly by Ca(2+)/calmodulin (CaM)-dependent protein kinase after rises in intracellular Ca(2+), we measured enzymatic activity that phosphorylates SRF (designated SRF kinase activity). Homogenates from 7-day-hypertrophied anterior latissimus dorsi muscles of roosters had more Ca(2+)-independent SRF kinase activity than their respective control muscles. However, no differences were noted in Ca(2+)/CaM-dependent SRF kinase activity between control and trained muscles. To determine whether the Ca(2+)-independent and Ca(2+)/CaM-dependent forms of Ca(2+)/CaM-dependent protein kinase II (CaMKII) might contribute to some of the SRF kinase activity, autocamtide-3, a synthetic substrate that is specific for CaMKII, was employed. While the Ca(2+)-independent form of CaMKII was increased, like the Ca(2+)-independent form of SRF kinase, no alteration in CaMKII occurred at 7 days of stretch overload. These observations suggest that some of SRF phosphorylation by skeletal muscle extracts could be due to CaMKII. To determine whether this adaptation was specific to the exercise type (i.e., hypertrophy), similar measurements were made in the white vastus lateralis muscle of rats that had completed 2 wk of voluntary running. Although Ca(2+)-independent SRF kinase was increased, no alteration occurred in Ca(2+)/CaM-dependent SRF kinase activity. Thus any role of Ca(2+)-independent SRF kinase signaling has downstream modulators specific to the exercise phenotype.

  5. Ca2+ paradox injury mediated through TRPC channels in mouse ventricular myocytes.

    Science.gov (United States)

    Kojima, Akiko; Kitagawa, Hirotoshi; Omatsu-Kanbe, Mariko; Matsuura, Hiroshi; Nosaka, Shuichi

    2010-12-01

    BACKGROUND AND PURPOSE The Ca(2+) paradox is an important phenomenon associated with Ca(2+) overload-mediated cellular injury in myocardium. The present study was undertaken to elucidate molecular and cellular mechanisms for the development of the Ca(2+) paradox. EXPERIMENTAL APPROACH Fluorescence imaging was performed on fluo-3 loaded quiescent mouse ventricular myocytes using confocal laser scanning microscope. KEY RESULTS The Ca(2+) paradox was readily evoked by restoration of the extracellular Ca(2+) following 10-20 min of nominally Ca(2+)-free superfusion. The Ca(2+) paradox was significantly reduced by blockers of transient receptor potential canonical (TRPC) channels (2-aminoethoxydiphenyl borate, Gd(3+), La(3+)) and anti-TRPC1 antibody. The sarcoplasmic reticulum (SR) Ca(2+) content, assessed by caffeine application, gradually declined during Ca(2+)-free superfusion, which was further accelerated by metabolic inhibition. Block of SR Ca(2+) leak by tetracaine prevented Ca(2+) paradox. The Na(+) /Ca(2+) exchange (NCX) blocker KB-R7943 significantly inhibited Ca(2+) paradox when applied throughout superfusion period, but had little effect when added for a period of 3 min before and during Ca(2+) restoration. The SR Ca(2+) content was better preserved during Ca(2+) depletion by KB-R7943. Immunocytochemistry confirmed the expression of TRPC1, in addition to TRPC3 and TRPC4, in mouse ventricular myocytes. CONCLUSIONS AND IMPLICATIONS These results provide evidence that (i) the Ca(2+) paradox is primarily mediated by Ca(2+) entry through TRPC (probably TRPC1) channels that are presumably activated by SR Ca(2+) depletion; and (ii) reverse mode NCX contributes little to the Ca(2+) paradox, whereas inhibition of NCX during Ca(2+) depletion improves SR Ca(2+) loading, and is associated with reduced incidence of Ca(2+) paradox in mouse ventricular myocytes.

  6. Interlamellar CA1 network in the hippocampus

    OpenAIRE

    Yang, Sunggu; Yang, Sungchil; Moreira, Thais; Hoffman, Gloria; Carlson, Greg C.; Bender, Kevin J.; Alger, Bradley E.; Tang, Cha-Min

    2014-01-01

    It has generally been thought that CA1 cells form only negligible connections with each other along the longitudinal axis of the hippocampus. But if CA1 cells were interconnected in an effective autoassociational network, this information would add a critical new dimension to our understanding of cellular processing within this structure. Here, we report the existence of a well-organized, longitudinally projecting synaptic network among CA1 pyramidal neurons. We further show that synapses of ...

  7. Localized Calcineurin Confers Ca2+-Dependent Inactivation Upon Neuronal L-Type Ca2+ Channels

    OpenAIRE

    2012-01-01

    Excitation-driven entry of Ca2+ through L-type voltage-gated Ca2+ channels controls gene expression in neurons and a variety of fundamental activities in other kinds of excitable cells. The probability of opening of CaV1.2 L-type channels is subject to pronounced enhancement by cAMP-dependent protein kinase (PKA), which is scaffolded to CaV1.2 channels by A-kinase anchoring proteins (AKAPs). CaV1.2 channels also undergo negative autoregulation via Ca2+-dependent inactivation (CDI), which stro...

  8. Glutamate excitotoxicity and Ca2+-regulation of respiration: Role of the Ca2+ activated mitochondrial transporters (CaMCs).

    Science.gov (United States)

    Rueda, Carlos B; Llorente-Folch, Irene; Traba, Javier; Amigo, Ignacio; Gonzalez-Sanchez, Paloma; Contreras, Laura; Juaristi, Inés; Martinez-Valero, Paula; Pardo, Beatriz; Del Arco, Araceli; Satrustegui, Jorgina

    2016-08-01

    Glutamate elicits Ca(2+) signals and workloads that regulate neuronal fate both in physiological and pathological circumstances. Oxidative phosphorylation is required in order to respond to the metabolic challenge caused by glutamate. In response to physiological glutamate signals, cytosolic Ca(2+) activates respiration by stimulation of the NADH malate-aspartate shuttle through Ca(2+)-binding to the mitochondrial aspartate/glutamate carrier (Aralar/AGC1/Slc25a12), and by stimulation of adenine nucleotide uptake through Ca(2+) binding to the mitochondrial ATP-Mg/Pi carrier (SCaMC-3/Slc25a23). In addition, after Ca(2+) entry into the matrix through the mitochondrial Ca(2+) uniporter (MCU), it activates mitochondrial dehydrogenases. In response to pathological glutamate stimulation during excitotoxicity, Ca(2+) overload, reactive oxygen species (ROS), mitochondrial dysfunction and delayed Ca(2+) deregulation (DCD) lead to neuronal death. Glutamate-induced respiratory stimulation is rapidly inactivated through a mechanism involving Poly (ADP-ribose) Polymerase-1 (PARP-1) activation, consumption of cytosolic NAD(+), a decrease in matrix ATP and restricted substrate supply. Glutamate-induced Ca(2+)-activation of SCaMC-3 imports adenine nucleotides into mitochondria, counteracting the depletion of matrix ATP and the impaired respiration, while Aralar-dependent lactate metabolism prevents substrate exhaustion. A second mechanism induced by excitotoxic glutamate is permeability transition pore (PTP) opening, which critically depends on ROS production and matrix Ca(2+) entry through the MCU. By increasing matrix content of adenine nucleotides, SCaMC-3 activity protects against glutamate-induced PTP opening and lowers matrix free Ca(2+), resulting in protracted appearance of DCD and protection against excitotoxicity in vitro and in vivo, while the lack of lactate protection during in vivo excitotoxicity explains increased vulnerability to kainite-induced toxicity in Aralar

  9. The initial 41Ca/40Ca ratios in two type A Ca-Al-rich inclusions: Implications for the origin of short-lived 41Ca

    Science.gov (United States)

    Liu, Ming-Chang

    2017-03-01

    This paper reports new 41Ca-41K isotopic data for two Type A CAIs, NWA 3118 #1Nb (Compact Type A) and Vigarano 3138 F8 (Fluffy Type A), from reduced CV3 chondrites. The NWA CAI is found to have carried live 41Ca at the level of (4.6 ± 1.9) ×10-9 , consistent with the proposed Solar System initial 41Ca /40Ca = 4.2 ×10-9 by Liu et al. (2012a). On the other hand, the Vigarano CAI does not have resolvable radiogenic 41K excesses that can be attributed to the decay of 41Ca. Combined with the 26Al data that have been reported for these two CAIs, we infer that the 41Ca distribution was not homogeneous when 26Al was widespread at the canonical level of 26Al /27Al = 5.2 ×10-5 . Such a 41Ca heterogeneity can be understood under two astrophysical contexts: in situ charged particle irradiation by the protoSun in the solar nebula that had inherited some baseline 10Be abundance from the molecular cloud, and Solar System formation in a molecular cloud enriched in 26Al and 41Ca contaminated by massive star winds. That said, more high quality 41Ca data are still needed to better understand the origin of this radionuclide.

  10. MiR-152 may silence translation of CaMK II and induce spontaneous immune tolerance in mouse liver transplantation.

    Directory of Open Access Journals (Sweden)

    Yan Wang

    Full Text Available Spontaneous immune tolerance in mouse liver transplantation has always been a hotspot in transplantation-immune research. Recent studies revealed that regulatory T cells (Tregs, hepatic satellite cells and Kupffer cells play a potential role in spontaneous immune tolerance, however the precise mechanism of spontaneous immune tolerance is still undefined. By using Microarray Chips, we investigated different immune regulatory factors to decipher critical mechanisms of spontaneous tolerance after mouse liver transplantation. Allogeneic (C57BL/6-C3H and syngeneic (C3H-C3H liver transplantation were performed by 6-8 weeks old male C57BL/6 and C3H mice. Graft samples (N = 4 each group were collected from 8 weeks post-operation mice. 11 differentially expressed miRNAs in allogeneic grafts (Allografts vs. syngeneic grafts (Syngrafts were identified using Agilent Mouse miRNA Chips. It was revealed that 185 genes were modified by the 11 miRNAs, furthermore, within the 185 target genes, 11 of them were tightly correlated with immune regulation after Gene Ontology (GO, Kyoto Encyclopedia of Genes and Genomes (KEGG analysis and Genbank data cross-comparison. Verified by real-time PCR and western blot, our results indicated that mRNA expression levels of IL-6 and TAB2 were respectively down regulated following miR-142-3p and miR-155 augment. In addition, increased miR-152 just silenced mRNA of CaMK II and down-regulated translation of CaMK II in tolerated liver grafts, which may play a critical role in immune regulation and spontaneous tolerance induction of mouse liver transplantation.

  11. Role of glycolytically generated ATP for CaMKII-mediated regulation of intracellular Ca2+ signaling in bovine vascular endothelial cells.

    Science.gov (United States)

    Aromolaran, Ademuyiwa S; Zima, Aleksey V; Blatter, Lothar A

    2007-07-01

    The role of glycolytically generated ATP in Ca(2+)/calmodulin-dependent kinase II (CaMKII)-mediated regulation of intracellular Ca(2+) signaling was examined in cultured calf pulmonary artery endothelial (CPAE) cells. Exposure of cells (extracellular Ca(2+) concentration = 2 mM) to glycolytic inhibitors 2-deoxy-D-glucose (2-DG), pyruvate (pyr) + beta-hydroxybutyrate (beta-HB), or iodoacetic acid (IAA) caused an increase of intracellular Ca(2+) concentration ([Ca(2+)](i)). CaMKII inhibitors (KN-93, W-7) triggered a similar increase of [Ca(2+)](i). The rise of [Ca(2+)](i) was characterized by a transient spike followed by a small sustained plateau of elevated [Ca(2+)](i). In the absence of extracellular Ca(2+) 2-DG caused an increase in [Ca(2+)](i), suggesting that inhibition of glycolysis directly triggered release of Ca(2+) from intracellular endoplasmic reticulum (ER) Ca(2+) stores. The inositol-1,4,5-trisphosphate receptor (IP(3)R) inhibitor 2-aminoethoxydiphenyl borate abolished the KN-93- and 2-DG-induced Ca(2+) response. Ca(2+) release was initiated in peripheral cytoplasmic processes from which activation propagated as a [Ca(2+)](i) wave toward the central region of the cell. Focal application of 2-DG resulted in spatially confined elevations of [Ca(2+)](i). Propagating [Ca(2+)](i) waves were preceded by [Ca(2+)](i) oscillations and small, highly localized elevations of [Ca(2+)](i) (Ca(2+) puffs). Inhibition of glycolysis with 2-DG reduced the KN-93-induced Ca(2+) response, and vice versa during inhibition of CaMKII 2-DG-induced Ca(2+) release was attenuated. Similar results were obtained with pyr + beta-HB and W-7. Furthermore, 2-DG and IAA caused a rapid increase of intracellular Mg(2+) concentration, indicating a concomitant drop of cellular ATP levels. In conclusion, CaMKII exerts a profound inhibition of ER Ca(2+) release in CPAE cells, which is mediated by glycolytically generated ATP, possibly through ATP-dependent phosphorylation of the IP(3)R.

  12. Intracellular Ca-carbonate biomineralization is widespread in cyanobacteria.

    Science.gov (United States)

    Benzerara, Karim; Skouri-Panet, Feriel; Li, Jinhua; Férard, Céline; Gugger, Muriel; Laurent, Thierry; Couradeau, Estelle; Ragon, Marie; Cosmidis, Julie; Menguy, Nicolas; Margaret-Oliver, Isabel; Tavera, Rosaluz; López-García, Purificación; Moreira, David

    2014-07-29

    Cyanobacteria have played a significant role in the formation of past and modern carbonate deposits at the surface of the Earth using a biomineralization process that has been almost systematically considered induced and extracellular. Recently, a deep-branching cyanobacterial species, Candidatus Gloeomargarita lithophora, was reported to form intracellular amorphous Ca-rich carbonates. However, the significance and diversity of the cyanobacteria in which intracellular biomineralization occurs remain unknown. Here, we searched for intracellular Ca-carbonate inclusions in 68 cyanobacterial strains distributed throughout the phylogenetic tree of cyanobacteria. We discovered that diverse unicellular cyanobacterial taxa form intracellular amorphous Ca-carbonates with at least two different distribution patterns, suggesting the existence of at least two distinct mechanisms of biomineralization: (i) one with Ca-carbonate inclusions scattered within the cell cytoplasm such as in Ca. G. lithophora, and (ii) another one observed in strains belonging to the Thermosynechococcus elongatus BP-1 lineage, in which Ca-carbonate inclusions lie at the cell poles. This pattern seems to be linked with the nucleation of the inclusions at the septum of the cells, showing an intricate and original connection between cell division and biomineralization. These findings indicate that intracellular Ca-carbonate biomineralization by cyanobacteria has been overlooked by past studies and open new perspectives on the mechanisms and the evolutionary history of intra- and extracellular Ca-carbonate biomineralization by cyanobacteria.

  13. Intracellular Ca-carbonate biomineralization is widespread in cyanobacteria

    Science.gov (United States)

    Benzerara, Karim; Skouri-Panet, Feriel; Li, Jinhua; Férard, Céline; Gugger, Muriel; Laurent, Thierry; Couradeau, Estelle; Ragon, Marie; Cosmidis, Julie; Menguy, Nicolas; Margaret-Oliver, Isabel; Tavera, Rosaluz; López-García, Purificación; Moreira, David

    2014-07-01

    Cyanobacteria have played a significant role in the formation of past and modern carbonate deposits at the surface of the Earth using a biomineralization process that has been almost systematically considered induced and extracellular. Recently, a deep-branching cyanobacterial species, Candidatus Gloeomargarita lithophora, was reported to form intracellular amorphous Ca-rich carbonates. However, the significance and diversity of the cyanobacteria in which intracellular biomineralization occurs remain unknown. Here, we searched for intracellular Ca-carbonate inclusions in 68 cyanobacterial strains distributed throughout the phylogenetic tree of cyanobacteria. We discovered that diverse unicellular cyanobacterial taxa form intracellular amorphous Ca-carbonates with at least two different distribution patterns, suggesting the existence of at least two distinct mechanisms of biomineralization: (i) one with Ca-carbonate inclusions scattered within the cell cytoplasm such as in Ca. G. lithophora, and (ii) another one observed in strains belonging to the Thermosynechococcus elongatus BP-1 lineage, in which Ca-carbonate inclusions lie at the cell poles. This pattern seems to be linked with the nucleation of the inclusions at the septum of the cells, showing an intricate and original connection between cell division and biomineralization. These findings indicate that intracellular Ca-carbonate biomineralization by cyanobacteria has been overlooked by past studies and open new perspectives on the mechanisms and the evolutionary history of intra- and extracellular Ca-carbonate biomineralization by cyanobacteria.

  14. Supralinear dendritic Ca(2+) signalling in young developing CA1 pyramidal cells.

    Science.gov (United States)

    Pohle, Jörg; Bischofberger, Josef

    2014-11-15

    Although Ca(2+) is critically important in activity-dependent neuronal development, not much is known about the regulation of dendritic Ca(2+) signals in developing neurons. Here, we used ratiometric Ca(2+) imaging to investigate dendritic Ca(2+) signalling in rat hippocampal pyramidal cells during the first 1-4 weeks of postnatal development. We show that active dendritic backpropagation of Nav channel-dependent action potentials (APs) evoked already large dendritic Ca(2+) transients in animals aged 1 week with amplitudes of ∼150 nm, similar to the amplitudes of ∼160 nM seen in animals aged 4 weeks. Although the AP-evoked dendritic Ca(2+) load increased about four times during the first 4 weeks, the peak amplitude of free Ca(2+) concentration was balanced by a four-fold increase in Ca(2+) buffer capacity κs (∼70 vs. ∼280). Furthermore, Ca(2+) extrusion rates increased with postnatal development, leading to a slower decay time course (∼0.2 s vs. ∼0.1 s) and more effective temporal summation of Ca(2+) signals in young cells. Most importantly, during prolonged theta-burst stimulation dendritic Ca(2+) signals were up to three times larger in cells at 1 week than at 4 weeks of age and much larger than predicted by linear summation, which is attributable to an activity-dependent slow-down of Ca(2+) extrusion. As Ca(2+) influx is four-fold smaller in young cells, the larger Ca(2+) signals are generated using four times less ATP consumption. Taken together, the data suggest that active backpropagations regulate dendritic Ca(2+) signals during early postnatal development. Remarkably, during prolonged AP firing, Ca(2+) signals are several times larger in young than in mature cells as a result of activity-dependent regulation of Ca(2+) extrusion rates.

  15. EMRE Is a Matrix Ca2+ Sensor that Governs Gatekeeping of the Mitochondrial Ca2+ Uniporter

    Directory of Open Access Journals (Sweden)

    Horia Vais

    2016-01-01

    Full Text Available The mitochondrial uniporter (MCU is an ion channel that mediates Ca2+ uptake into the matrix to regulate metabolism, cell death, and cytoplasmic Ca2+ signaling. Matrix Ca2+ concentration is similar to that in cytoplasm, despite an enormous driving force for entry, but the mechanisms that prevent mitochondrial Ca2+ overload are unclear. Here, we show that MCU channel activity is governed by matrix Ca2+ concentration through EMRE. Deletion or charge neutralization of its matrix-localized acidic C terminus abolishes matrix Ca2+ inhibition of MCU Ca2+ currents, resulting in MCU channel activation, enhanced mitochondrial Ca2+ uptake, and constitutively elevated matrix Ca2+ concentration. EMRE-dependent regulation of MCU channel activity requires intermembrane space-localized MICU1, MICU2, and cytoplasmic Ca2+. Thus, mitochondria are protected from Ca2+ depletion and Ca2+ overload by a unique molecular complex that involves Ca2+ sensors on both sides of the inner mitochondrial membrane, coupled through EMRE.

  16. Biphasic decay of the Ca transient results from increased sarcoplasmic reticulum Ca leak

    Science.gov (United States)

    Sankaranarayanan, Rajiv; Li, Yatong; Greensmith, David J.; Eisner, David A.

    2016-01-01

    Key points Ca leak from the sarcoplasmic reticulum through the ryanodine receptor (RyR) reduces the amplitude of the Ca transient and slows its rate of decay.In the presence of β‐adrenergic stimulation, RyR‐mediated Ca leak produces a biphasic decay of the Ca transient with a fast early phase and a slow late phase.Two forms of Ca leak have been studied, Ca‐sensitising (induced by caffeine) and non‐sensitising (induced by ryanodine) and both induce biphasic decay of the Ca transient.Only Ca‐sensitising leak can be reversed by traditional RyR inhibitors such as tetracaine.Ca leak can also induce Ca waves. At low levels of leak, waves occur. As leak is increased, first biphasic decay and then slowed monophasic decay is seen. The level of leak has major effects on the shape of the Ca transient. Abstract In heart failure, a reduction in Ca transient amplitude and contractile dysfunction can by caused by Ca leak through the sarcoplasmic reticulum (SR) Ca channel (ryanodine receptor, RyR) and/or decreased activity of the SR Ca ATPase (SERCA). We have characterised the effects of two forms of Ca leak (Ca‐sensitising and non‐sensitising) on calcium cycling and compared with those of SERCA inhibition. We measured [Ca2+]i with fluo‐3 in voltage‐clamped rat ventricular myocytes. Increasing SR leak with either caffeine (to sensitise the RyR to Ca activation) or ryanodine (non‐sensitising) had similar effects to SERCA inhibition: decreased systolic [Ca2+]i, increased diastolic [Ca2+]i and slowed decay. However, in the presence of isoproterenol, leak produced a biphasic decay of the Ca transient in the majority of cells while SERCA inhibition produced monophasic decay. Tetracaine reversed the effects of caffeine but not of ryanodine. When caffeine (1 mmol l−1) was added to a cell which displayed Ca waves, the wave frequency initially increased before waves disappeared and biphasic decay developed. Eventually (at higher caffeine concentrations), the

  17. Toward models for the full oxygen-evolving complex of photosystem II by ligand coordination to lower the symmetry of the Mn3CaO4 cubane: demonstration that electronic effects facilitate binding of a fifth metal.

    Science.gov (United States)

    Kanady, Jacob S; Lin, Po-Heng; Carsch, Kurtis M; Nielsen, Robert J; Takase, Michael K; Goddard, William A; Agapie, Theodor

    2014-10-15

    Synthetic model compounds have been targeted to benchmark and better understand the electronic structure, geometry, spectroscopy, and reactivity of the oxygen-evolving complex (OEC) of photosystem II, a low-symmetry Mn4CaOn cluster. Herein, low-symmetry Mn(IV)3GdO4 and Mn(IV)3CaO4 cubanes are synthesized in a rational, stepwise fashion through desymmetrization by ligand substitution, causing significant cubane distortions. As a result of increased electron richness and desymmetrization, a specific μ3-oxo moiety of the Mn3CaO4 unit becomes more basic allowing for selective protonation. Coordination of a fifth metal ion, Ag(+), to the same site gives a Mn3CaAgO4 cluster that models the topology of the OEC by displaying both a cubane motif and a "dangler" transition metal. The present synthetic strategy provides a rational roadmap for accessing more accurate models of the biological catalyst.

  18. Ryanodine Receptor Phosphorylation by CaMKII Promotes Spontaneous Ca2+ Release Events in a Rodent Model of Early Stage Diabetes: the Arrhythmogenic Substrate

    Science.gov (United States)

    Sommese, Leandro; Valverde, Carlos A; Blanco, Paula; Castro, María Cecilia; Rueda, Omar Velez; Kaetzel, Marcia; Dedman, John; Anderson, Mark E.; Mattiazzi, Alicia; Palomeque, Julieta

    2016-01-01

    Background Heart failure and arrhythmias occur more frequently in patients with type 2 diabetes (T2DM) than in the general population. T2DM is preceded by a prediabetic condition marked by elevated reactive oxygen species (ROS) and subclinical cardiovascular defects. Although multifunctional Ca2+ calmodulin-dependent protein kinase II (CaMKII) is ROS-activated and CaMKII hyperactivity promotes cardiac diseases, a link between prediabetes and CaMKII in the heart is unprecedented. Objectives to prove the hypothesis that increased ROS and CaMKII activity contribute to heart failure and arrhythmogenic mechanisms in early stage diabetes. Methods-Results Echocardiography, electrocardiography, biochemical and intracellular Ca2+ (Ca2+i) determinations were performed in fructose-rich diet -induced impaired glucose tolerance, a prediabetes model, in rodents. Fructose-rich diet rats showed decreased contractility and hypertrophy associated with increased CaMKII activity, ROS production, oxidized CaMKII and enhanced CaMKII-dependent ryanodine receptor (RyR2) phosphorylation compared to rats fed with control diet. Isolated cardiomyocytes from fructose-rich diet showed increased spontaneous Ca2+i release events associated with spontaneous contractions, which were prevented by KN-93, a CaMKII inhibitor, or addition of Tempol, a ROS scavenger, to the diet. Moreover, fructose-rich diet myocytes showed increased diastolic Ca2+ during the burst of spontaneous Ca2+i release events. Micetreated with Tempol or with sarcoplasmic reticulum-targeted CaMKII-inhibition by transgenic expression of the CaMKII inhibitory peptide AIP, were protected from fructose-rich diet-induced spontaneous Ca2+i release events, spontaneous contractions and arrhythmogenes is in vivo, despite ROS increases. Conclusions RyR2 phosphorylation by ROS-activated CaMKII, contributes to impaired glucose tolerance-induced arrhythmogenic mechanisms, suggesting that CaMKII inhibition could prevent prediabetic

  19. MEDIUL ACADEMIC CA FACTOR DE ASIGURARE A CONTINUITĂŢII ŞI INTERCONEXIUNII DINTRE CICLURILE ÎNVĂŢĂMÂNTULUI SUPERIOR

    Directory of Open Access Journals (Sweden)

    Maia ŞEVCIUC

    2017-03-01

    Full Text Available În articol este abordată problema privind mediul academic ca factor de asigurare a continuităţii şi interconexiunii dintre ciclurile învăţământului superior. În acest sens sunt analizate diferite concepte cu referire la mediul academic, sunt deduse principiile de concepere a unui mediu academic eficient, dar şi modalităţi de realizare a continuităţii şi inter­conexiunii dintre ciclurile învăţământului superior. Sunt propuse sugestii de asigurare a continuităţii şi interconexiunii dintre ciclurile învăţământului superior.ACADEMIC ENVIRONMENT AS A FACTOR IN ENSURING CONTINUITY AND INTERCONNECTION BETWEEN CYCLES OF HIGHER EDUCATIONThe article addressed academics as a factor of continuity and interconnection between cycles of higher education. In this sense analyzed different concepts with reference to academia, they are deducted design principles of an academic environment effectively, but also ways of continuity and interconnection between cycles of higher education, are proposed suggestions to ensure continuity and interconnection between cycles of higher education.

  20. Coping with Asymmetric Channel Losses in CSMA/CA

    DEFF Research Database (Denmark)

    Paramanathan, Achuthan; Roetter, Daniel Enrique Lucani; Fitzek, Frank

    2013-01-01

    Inspired by the discrepancy between past theoretical analysis and real measurements for high-load scenarios for intersession network coding, we pinpoint and analyze the source of this discrepancy in wireless networks implementing a CSMA/CA medium access scheme. Our analysis shows that CSMA/CA is ......) confirm the sensitivity of the CSMA/CA scheme in real implementations, and (ii) shows that our adaptive protocol provides a simple, yet potent mechanism to cope with asymmetric channel losses and ultimately to enhance end-to-end throughput in high-load scenarios....

  1. Ischemic damage in hippocampal CA1 is dependent on glutamate release and intact innervation from CA3

    DEFF Research Database (Denmark)

    Benveniste, H; Jørgensen, M B; Sandberg, M;

    1989-01-01

    The removal of glutamatergic afferents to CA1 by destruction of the CA3 region is known to protect CA1 pyramidal cells against 10 min of transient global ischemia. To investigate further the pathogenetic significance of glutamate, we measured the release of glutamate in intact and CA3-lesioned CA...... is dependent on glutamate release and intact innervation from CA3....

  2. Polyamine triggering of exocytosis in Paramecium involves an extracellular Ca(2+)/(polyvalent cation)-sensing receptor, subplasmalemmal Ca-store mobilization and store-operated Ca(2+)-influx via unspecific cation channels.

    Science.gov (United States)

    Klauke, N; Blanchard, M; Plattner, H

    2000-03-15

    The polyamine secretagogue, aminoethyldextran (AED), causes a cortical [Ca(2+)] transient in Paramecium cells, as analyzed by fluorochrome imaging. Our most essential findings are: (i) Cortical Ca(2+) signals also occur when AED is applied in presence of the fast Ca(2+) chelator, BAPTA. (ii) Extracellular La(3+) application causes within seconds a rapid, reversible fluorescence signal whose reversibility can be attributed to a physiological [Ca(2+)](i) transient (while injected La(3+) causes a sustained fluorescence signal). (iii) Simply increasing [Ca(2+)](o) causes a similar rapid, short-lived [Ca(2+)](i) transient. All these phenomena, (i-iii), are compatible with activation of an extracellular "Ca(2+)/(polyvalent cation)-sensing receptor" known from some higher eukaryotic systems, where this sensor (responding to Ca(2+), La(3+) and some multiply charged cations) is linked to cortical calcium stores which, thus, are activated. In Paramecium, such subplasmalemmal stores ("alveolar sacs") are physically linked to the cell membrane and they can also be activated by the Ca(2+) releasing agent, 4-chloro-m-cresol, just like in Sarcoplasmic Reticulum. Since this drug causes a cortical Ca(2+) signal also in absence of Ca(2+)(o) we largely exclude a "Ca(2+)-induced Ca(2+) release" (CICR) mechanism. Our finding of increased cortical Ca(2+) signals after store depletion and re-addition of extracellular Ca(2+) can be explained by a "store-operated Ca(2+) influx" (SOC), i.e., a Ca(2+) influx superimposing store activation. AED stimulation in presence of Mn(2+)(o) causes fluorescence quenching in Fura-2 loaded cells, indicating involvement of unspecific cation channels. Such channels, known to occur in Paramecium, share some general characteristics of SOC-type Ca(2+) influx channels. In conclusion, we assume the following sequence of events during AED stimulated exocytosis: (i) activation of an extracellular Ca(2+)/polyamine-sensing receptor, (ii) release of Ca(2+) from

  3. Immobilization of Fusarium verticillioides fungus on nano-silica (NSi-Fus): a novel and efficient biosorbent for water treatment and solid phase extraction of Mg(II) and Ca(II).

    Science.gov (United States)

    Mahmoud, Mohamed E; Yakout, Amr A; Abdel-Aal, Hany; Osman, Maher M

    2013-04-01

    Biosorption and water treatment of Mg(II) and Ca(II) hardness was designed via surface loading of heat inactivated Fusarium verticillioides fungus (Fus) on nano-silica (NSi) for developing the (NSi-Fus) as a novel biosorbent. Surface characterization was confirmed by FT-IR and SEM analysis. The (NSi), (Fus) and (NSi-Fus) sorbents were investigated for removal of Mg(II) and Ca(II) by using the batch equilibrium technique under the influence of solution pH, contact time, sorbent dosage, initial metal concentration and interfering ion. The maximum magnesium capacity values were identified as 600.0, 933.3 and 1000.0 μmole g(-1) while, the maximum calcium values were 1066.7, 1800.0 and 1333.3 μmole g(-1) for (NSi), (Fus) and (NSi-Fus), respectively. Sorption equilibria were established in ∼20 min and the data were well described by both Langmuir and Freundlich models. The potential applications of these biosorbents for water-softening and extraction of magnesium and calcium from sea water samples were successfully accomplished.

  4. Localized calcineurin confers Ca2+-dependent inactivation on neuronal L-type Ca2+ channels.

    Science.gov (United States)

    Oliveria, Seth F; Dittmer, Philip J; Youn, Dong-ho; Dell'Acqua, Mark L; Sather, William A

    2012-10-31

    Excitation-driven entry of Ca(2+) through L-type voltage-gated Ca(2+) channels controls gene expression in neurons and a variety of fundamental activities in other kinds of excitable cells. The probability of opening of Ca(V)1.2 L-type channels is subject to pronounced enhancement by cAMP-dependent protein kinase (PKA), which is scaffolded to Ca(V)1.2 channels by A-kinase anchoring proteins (AKAPs). Ca(V)1.2 channels also undergo negative autoregulation via Ca(2+)-dependent inactivation (CDI), which strongly limits Ca(2+) entry. An abundance of evidence indicates that CDI relies upon binding of Ca(2+)/calmodulin (CaM) to an isoleucine-glutamine motif in the carboxy tail of Ca(V)1.2 L-type channels, a molecular mechanism seemingly unrelated to phosphorylation-mediated channel enhancement. But our work reveals, in cultured hippocampal neurons and a heterologous expression system, that the Ca(2+)/CaM-activated phosphatase calcineurin (CaN) is scaffolded to Ca(V)1.2 channels by the neuronal anchoring protein AKAP79/150, and that overexpression of an AKAP79/150 mutant incapable of binding CaN (ΔPIX; CaN-binding PXIXIT motif deleted) impedes CDI. Interventions that suppress CaN activity-mutation in its catalytic site, antagonism with cyclosporine A or FK506, or intracellular perfusion with a peptide mimicking the sequence of the phosphatase's autoinhibitory domain-interfere with normal CDI. In cultured hippocampal neurons from a ΔPIX knock-in mouse, CDI is absent. Results of experiments with the adenylyl cyclase stimulator forskolin and with the PKA inhibitor PKI suggest that Ca(2+)/CaM-activated CaN promotes CDI by reversing channel enhancement effectuated by kinases such as PKA. Hence, our investigation of AKAP79/150-anchored CaN reconciles the CaM-based model of CDI with an earlier, seemingly contradictory model based on dephosphorylation signaling.

  5. Isolation and characterization of higher metallofullerenes Ca@C92 and Ca@C94

    Indian Academy of Sciences (India)

    Yuliang Che; Hua Yang; Hongxiao Jin; Chunxin Lu; Ziyang Liu

    2009-05-01

    We report for the first time isolation of Ca@C92 and Ca@C94 by multi-stage highperformance liquid chromatography technique without recycling equipment. It is notable that higher metallofullerenes containing alkaline earth metal ions could be isolated although their relative yields are extremely low. Ca@C92 and Ca@C94 are also confirmed by LD-TOF mass spectrometry and characterrized by UV-Vis-NIR absorption measurements.

  6. Ca(V)1 and Ca(V)2 channels engage distinct modes of Ca(2+) signaling to control CREB-dependent gene expression.

    Science.gov (United States)

    Wheeler, Damian G; Groth, Rachel D; Ma, Huan; Barrett, Curtis F; Owen, Scott F; Safa, Parsa; Tsien, Richard W

    2012-05-25

    Activity-dependent gene expression triggered by Ca(2+) entry into neurons is critical for learning and memory, but whether specific sources of Ca(2+) act distinctly or merely supply Ca(2+) to a common pool remains uncertain. Here, we report that both signaling modes coexist and pertain to Ca(V)1 and Ca(V)2 channels, respectively, coupling membrane depolarization to CREB phosphorylation and gene expression. Ca(V)1 channels are advantaged in their voltage-dependent gating and use nanodomain Ca(2+) to drive local CaMKII aggregation and trigger communication with the nucleus. In contrast, Ca(V)2 channels must elevate [Ca(2+)](i) microns away and promote CaMKII aggregation at Ca(V)1 channels. Consequently, Ca(V)2 channels are ~10-fold less effective in signaling to the nucleus than are Ca(V)1 channels for the same bulk [Ca(2+)](i) increase. Furthermore, Ca(V)2-mediated Ca(2+) rises are preferentially curbed by uptake into the endoplasmic reticulum and mitochondria. This source-biased buffering limits the spatial spread of Ca(2+), further attenuating Ca(V)2-mediated gene expression.

  7. Ca(2+) signalling in the Golgi apparatus.

    Science.gov (United States)

    Pizzo, Paola; Lissandron, Valentina; Capitanio, Paola; Pozzan, Tullio

    2011-08-01

    The Golgi apparatus plays a central role in lipid and protein post-translational modification and sorting. Morphologically the organelle is heterogeneous and it is possible to distinguish stacks of flat cysternae (cis- and medial Golgi), tubular-reticular networks and vesicles (trans-Golgi). These morphological differences parallel a distinct functionality with a selective distribution and complementary roles of the enzymes found in the different compartments. The Golgi apparatus has been also shown to be involved in Ca(2+) signalling: it is indeed endowed with Ca(2+) pumps, Ca(2+) release channels and Ca(2+) binding proteins and is thought to participate in determining the spatio-temporal complexity of the Ca(2+) signal within the cell, though this role is still poorly understood. Recently, it has been demonstrated that the organelle is heterogeneous in terms of Ca(2+) handling and selective reduction of Ca(2+) concentration, both in vitro and in a genetic human disease, within one of its sub-compartment results in alterations of protein trafficking within the secretory pathway and of the entire Golgi morphology. In this paper we review the available information on the Ca(2+) toolkit within the Golgi, its heterogeneous distribution in the organelle sub-compartments and discuss the implications of these characteristics for the physiopathology of the Golgi apparatus.

  8. LATS refining ladle slag modifying with CaO-CaF2

    Institute of Scientific and Technical Information of China (English)

    Hongming Wang; Guirong Li; Zhongming Ren; Bo Li; Xuejun Zhang; Guomin Shi

    2007-01-01

    To reduce the slag sticking onto the snorkel of the ladle during the ladle alloying treatment station (LATS) process, CaO-CaF2 (the mass ratio of CaO/CaF2 is 1:1) was employed as the modifier of the LATS refining ladle slag. The effect of CaO-CaF2 on the melting point, viscosity, and desulfurizing capability of the ladle slag was investigated. The melting point of the unmodified ladle slag is 1439°C. When adding 20wt% CaO-CaF2, the melting point is decreased to 1327°C. At 1500°C, the viscosity of the unmodified ladle slag is 6.5 Pa·s, which can be decreased lower than 2 Pa·s by adding more than 10wt% CaO-CaF2. The experimental results of desulfurization of the melts show that the desulfurizing power of the ladle slag can be enhanced by adding CaO-CaF2.

  9. By Regulating Mitochondrial Ca2+-Uptake UCP2 Modulates Intracellular Ca2+.

    Directory of Open Access Journals (Sweden)

    Lukas Jaroslaw Motloch

    Full Text Available The possible role of UCP2 in modulating mitochondrial Ca2+-uptake (mCa2+-uptake via the mitochondrial calcium uniporter (MCU is highly controversial.Thus, we analyzed mCa2+-uptake in isolated cardiac mitochondria, MCU single-channel activity in cardiac mitoplasts, dual Ca2+-transients from mitochondrial ((Ca2+m and intracellular compartment ((Ca2+c in the whole-cell configuration in cardiomyocytes of wild-type (WT and UCP2-/- mice.Isolated mitochondria showed a Ru360 sensitive mCa2+-uptake, which was significantly decreased in UCP2-/- (229.4±30.8 FU vs. 146.3±23.4 FU, P0.05 and transsarcolemmal Ca2+-influx was inhibited suggesting a possible compensatory mechanism. Additionally, we observed an inhibitory effect of ATP on mCa2+-uptake in WT mitoplasts and (Ca2+m of cardiomyocytes leading to an increase of (Ca2+c while no ATP dependent effect was observed in UCP2-/-.Our results indicate regulatory effects of UCP2 on mCa2+-uptake. Furthermore, we propose, that previously described inhibitory effects on MCU by ATP may be mediated via UCP2 resulting in changes of excitation contraction coupling.

  10. Ca-Dependent Folding of Human Calumenin

    Science.gov (United States)

    Mazzorana, Marco; Hussain, Rohanah; Sorensen, Thomas

    2016-01-01

    Human calumenin (hCALU) is a six EF-hand protein belonging to the CREC family. As other members of the family, it is localized in the secretory pathway and regulates the activity of SERCA2a and of the ryanodine receptor in the endoplasmic reticulum (ER). We have studied the effects of Ca2+ binding to the protein and found it to attain a more compact structure upon ion binding. Circular Dichroism (CD) measurements suggest a major rearrangement of the protein secondary structure, which reversibly switches from disordered at low Ca2+ concentrations to predominantly alpha-helical when Ca2+ is added. SAXS experiments confirm the transition from an unfolded to a compact structure, which matches the structural prediction of a trilobal fold. Overall our experiments suggest that calumenin is a Ca2+ sensor, which folds into a compact structure, capable of interacting with its molecular partners, when Ca2+ concentration within the ER reaches the millimolar range. PMID:26991433

  11. Levels of CEA, CA153, CA199, CA724 and AFP in nipple discharge of breast cancer patients.

    Science.gov (United States)

    Zhao, Song; Mei, Yu; Wang, Yongmei; Zhu, Jiang; Zheng, Guixi; Ma, Rong

    2015-01-01

    The distinction between breast cancer and benign breast diseases with nipple discharge remains an important diagnostic challenge. The purpose of this study was to predict the potential usefulness of tumor markers in nipple discharge and to investigate the relationship of tumor markers and clinical characteristics with breast cancer.One hundred and eleven patients with nipple discharge received breast surgery from November 2013 to December 2014 were included in the study. We evaluated levels of five tumor markers (CEA, CA153, CA199, CA724 and AFP) prior to treatment. Patients were divided into two groups according to postoperative pathological results: 30 cases in breast cancer group and 81 cases in benign group. The relationships of clinical characteristics with breast cancer were investigated by multivariate analysis with a logistic regression model.It showed significant differences in levels of nipple discharge CEA (P AFP (P = 0.834) among two groups. Logistic regression analysis demonstrated complaint, age, menopause, abnormal palpable mass, CEA and CA153 were associated with breast cancer. In summary, measurements of CA199, CA724 and AFP in nipple discharge are not of great clinical value. Detecting CEA and CA153 in nipple dischargecould potentially be used for the early detection of breast cancer with in high-risk populations.

  12. Effect of salinity and temperature on the adsorption of Hg(II) from aqueous solutions by a Ca-montmorillonite.

    Science.gov (United States)

    Green-Ruiz, C

    2009-01-01

    Use of clay minerals for removing mercury is an effective technology for the treatment of industrial wastewaters and can become an effective tool for the remediation of coastal ecosystems polluted with this metal. Calcic montmorillonite was employed for adsorbing Hg(II) ions from aqueous solutions at different conditions of salinity (0, 20 and 35 g NaCl L(-1)), temperature (15, 25 and 35 degrees C), and initial concentrations (0.25, 0.50, 1.00, 2.50, 5.00 and 10.00 mg Hg L(-1)). It was observed that 0.4 g dry weight of montmorillonite removed from 0.02 mg g(-1) (at 0.25 mg L(-1) of Hg(II)) to 0.68 mg g(-1) (at 10.0 mg L(-1) of Hg(II)) at 25 degrees C, salinity of 0 g NaCl L(-1) and pH of 6. The initial concentration of Hg(II) and salinity had an effect on the behaviour of the adsorption process, which was temperature independent. The data fit well the Freundlich adsorption isotherm, indicating that heterogeneous conditions prevail in this process.

  13. SR-targeted CaMKII inhibition improves SR Ca2+ handling, but accelerates cardiac remodeling in mice overexpressing CaMKIIδC

    OpenAIRE

    Huke, Sabine; DeSantiago, Jaime; Kaetzel, Marcia A.; Mishra, Shikha; Brown, Joan H.; Dedman, John R.; Bers, Donald M.

    2010-01-01

    Cardiac myocyte overexpression of CaMKIIδC leads to cardiac hypertrophy and heart failure (HF) possibly caused by altered myocyte Ca2+ handling. A central defect might be the marked CaMKII-induced increase in diastolic sarcoplasmic reticulum (SR) Ca2+ leak which decreases SR Ca2+ load and Ca2+ transient amplitude. We hypothesized that inhibition of CaMKII near the SR membrane would decrease the leak, improve Ca2+ handling and prevent the development of contractile dysfunction and HF. To test ...

  14. Results of measuring internal Ca absorption and Ca kinetics with /sup 47/Ca in patients suffering from chronically recurrent urolithiasis

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, L.; Esther, G.; Serfling, D.; Bast, R. (Rostock Univ. (German Democratic Republic). Radiologische Klinik)

    1983-07-01

    47 patients with chronically recurrent calcium lithiasis (with between 3 and over 100 stone episodes) and an average age of 43.2 years have been examined. The Ca absorption lay between 42.7% and 90.0% of the dose, the average was 59.3% with a standard deviation of +- 12.9. This is higher than in persons with healthy kidneys. The Ca absorption is significantly lower in patients with renal insufficiency. Studies on Ca kinetics revealed turnover rates and pool sizes within the normal range.

  15. Isospin effects in {sup 40,48}Ca+{sup 40,48}Ca collisions

    Energy Technology Data Exchange (ETDEWEB)

    Henzl, V., E-mail: henzl@mit.ed [MSU-NSCL, 1 Cyclotron, East Lansing MI, 48824 (United States); Henzlova, D.; Kilburn, M. [MSU-NSCL, 1 Cyclotron, East Lansing MI, 48824 (United States); Verde, G. [INFN, Sezione di Catania. 64 Via S. Sofia, I-95123, Catania (Italy); Brown, D. [MSU-NSCL, 1 Cyclotron, East Lansing MI, 48824 (United States); Chbihi, A. [GANIL, CEA et IN2P3-CNRS, B.P. 5027, F-14076 Caen Cedex (France); Coupland, D. [MSU-NSCL, 1 Cyclotron, East Lansing MI, 48824 (United States); Elson, J. [Departments of Chemistry and Physics, Washington University, St. Louis, MO 63130 (United States); Famiano, M. [Western Michigan University, 2229 Everett Tower, Kalamazoo, MI 49008-5252 (United States); Herlitzius, C. [MSU-NSCL, 1 Cyclotron, East Lansing MI, 48824 (United States); Hudan, S. [Indiana Univ. Cyclotron Facility, 2401 Milo B. Sampson Lane, Bloomington, IN 47405-4001 (United States); Lee, J.; Lukyanov, S.; Lynch, W.; Rogers, A.; Sanetullaev, A. [MSU-NSCL, 1 Cyclotron, East Lansing MI, 48824 (United States); Sobotka, L. [Departments of Chemistry and Physics, Washington University, St. Louis, MO 63130 (United States); Souza, R.T. de [Indiana Univ. Cyclotron Facility, 2401 Milo B. Sampson Lane, Bloomington, IN 47405-4001 (United States); Sun, Z.Y.; Tsang, B. [MSU-NSCL, 1 Cyclotron, East Lansing MI, 48824 (United States)

    2010-03-01

    The isospin dependence of two proton correlations is studied in {sup 40}Ca+{sup 40}Ca and {sup 48}Ca+{sup 48}Ca collisions at E/A=80MeV. Measurements were performed with the HiRA detector array complemented by the 4pi Ball at NSCL. We observe a strong isospin dependence of the pp-correlation functions; however the emitting source radius extracted using the imaging technique yields no sensitivity to the isospin of the reaction system. We interpret this result as a consequence of smaller fraction of fast proton emission in the neutron rich {sup 48}Ca system.

  16. Toosendanin increases free-Ca2+ concentration in NG108-15 cells via L-type Ca2+ channels

    Institute of Scientific and Technical Information of China (English)

    Tong-hui XU; Jun DING; Yu-liang SHI

    2004-01-01

    AIM: To examine if toosendanin (TSN) affects intracellular free-Ca2+ concentration ([Ca2+]i) in neuroblastomaxglioma hybrid cells (NG108-15 cells). METHODS: The [Ca2+]i was determined by laser-scanning confocal microscopic imaging technique in which Fluo-3 was used as Ca2+ indicator. RESULTS: TSN induced an increase in resting [Ca2+]i and in high K+-evoked Ca2+ transient in differentiated NG108-15 cells. The TSN-induced increase in [Ca2+]i was dose-dependent and disappeared in CdCl2-, nifedipine-containing or Ca2+-free solution, and appeared after washing out the Ca2+ channel blockers or adding Ca2+. CONCLUSION: TSN increased [Ca2+]i in differentiated NG108-15 cells. The [Ca2+]i enhancement was due to the influx of extracellular Ca2+ and related to L-type Ca2+ channels.

  17. Ion pathways in the sarcoplasmic reticulum Ca2+-ATPase.

    Science.gov (United States)

    Bublitz, Maike; Musgaard, Maria; Poulsen, Hanne; Thøgersen, Lea; Olesen, Claus; Schiøtt, Birgit; Morth, J Preben; Møller, Jesper Vuust; Nissen, Poul

    2013-04-12

    The sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA) is a transmembrane ion transporter belonging to the P(II)-type ATPase family. It performs the vital task of re-sequestering cytoplasmic Ca(2+) to the sarco/endoplasmic reticulum store, thereby also terminating Ca(2+)-induced signaling such as in muscle contraction. This minireview focuses on the transport pathways of Ca(2+) and H(+) ions across the lipid bilayer through SERCA. The ion-binding sites of SERCA are accessible from either the cytoplasm or the sarco/endoplasmic reticulum lumen, and the Ca(2+) entry and exit channels are both formed mainly by rearrangements of four N-terminal transmembrane α-helices. Recent improvements in the resolution of the crystal structures of rabbit SERCA1a have revealed a hydrated pathway in the C-terminal transmembrane region leading from the ion-binding sites to the cytosol. A comparison of different SERCA conformations reveals that this C-terminal pathway is exclusive to Ca(2+)-free E2 states, suggesting that it may play a functional role in proton release from the ion-binding sites. This is in agreement with molecular dynamics simulations and mutational studies and is in striking analogy to a similar pathway recently described for the related sodium pump. We therefore suggest a model for the ion exchange mechanism in P(II)-ATPases including not one, but two cytoplasmic pathways working in concert.

  18. Ca2+ sparks and Ca2+ glows in superior cervical ganglion neurons

    Institute of Scientific and Technical Information of China (English)

    Li-jun YAO; Cai-hong WU; Jie LIU; Zhuan ZHOU; He-ping CHENG; Gang WANG; Kun-fu OU-YANG; Chao-liang WEI; Xian-hua WANG; Shi-rong WANG; Wei YAO; Hong-ping HUANG; Jian-hong LUO

    2006-01-01

    Aim: Ca2+ release from the endoplasmic reticulum (ER) is an integral component of neuronal Ca2+ signaling. The present study is to investigate properties of local Ca2+ release events in superior cervical ganglion (SCO) neurons. Methods: Primary cultured SCO neurons were prepared from neonatal rats (P3-P7). Low concentration of caffeine was used to induce Ca2+ release from the ER Ca2+ store, and intracellular Ca2+ was recorded by high-resolution line scan confocal imaging and the Ca2+ indicator Fluo-4. Results: Two populations of local Ca2+ release events with distinct temporal characteristics were evoked by 1.5 mmol/L caffeine near the surface membrane in the soma and the neurites of SCG neurons. Brief events similar to classic Ca2+ sparks lasted a few hundreds of milliseconds, whereas long-lasting events displayed duration up to tens of seconds. Typical somatic and neurite sparks were of 0.3- and 0.52-fold increase in local Fluo-4 fluorescence, respectively. Typical Ca2+ glows were brighter (△F/F0 approximately 0.6), but were highly confined in space. The half maximum of full duration of neurite sparks was much longer than those in the soma (685 vs 381 ms). Conclusion: Co-existence of Ca2+ sparks and Ca2+ glows in SCG neurons indicates distinctive local regulation of Ca2+ release kinetics. The local Ca2+ signals of variable, site-specific temporal length may bear important implications in encoding a "memory" of the trigger signal.

  19. Serum level of TSGF,CA242 and CA19-9 in pancreatic cancer

    Institute of Scientific and Technical Information of China (English)

    Jing-Ting Jiang; Chang-Ping Wu; Hai-Feng Deng; Ming-Yang Lu; Jun Wu; Hong-Yu Zhang; Wen-Hui Sun; Mei Ji

    2004-01-01

    AIM: To establish a method to detect the expression of the tumor specific growth factor TSGF, CA242 and CA19-9 in serum and evaluate their value in diagnosis of pancreatic cancer.METHODS: ELISA and Biochemical colorimetric assay were used to detect the serum content of TSGF, CA242 and CA19-9 in 200 normal cases, 52 pancreatitis patients and 96 pancreatic cancer patients.RESULTS: The positive likelihood ratios of TSGF, CA242and CA19-9 were 5.4, 12.6 and 6.3, respectively, and their negative likelihood ratios were 0.10, 0.19 and 0.17,respectively. With single tumor marker diagnosed pancreatic cancer, the highest sensitivity and specificity of TSGF were 91.6% and 93.5%. In combined test with 3 markers, when all of them were positive, the sensitivity changed to 77.0%and the specificity and the positive predictive value were 100%. The levels of TSGF and CA242 were significantly higher in the patients with pancreatic cancer of head than those in the patients with pancreatic cancer of body, tail and whole pancreas, but the expression of CA19-9 had no correlation with the positions of the pancreatic cancer. The sensitivity of TSGF, CA242 and CA19-9 was increased with the progress in stages of pancreatic cancer. In stage I, the sensitivity of TSGF was markedly higher than CA242 and CA19-9.CONCLUSION: The combined use of TSGF, CA242 and CA19-9 expressions can elevate the specificity for pancreatic cancer diagnosis. And it shows that it plays an important role to differentiate positions and tissue typing. It is a forepart diagnosis for the pancreatic cancer by combination checking.There is very important correlation between the three markers and the pancreatic cancer.

  20. Behavior of CaO and Calcium in pure Magnesium

    Institute of Scientific and Technical Information of China (English)

    HA Seong-Ho; LEE Jin-Kyu; JO Hyung-Ho; JUNG Seung-Boo; KIM Shae K.

    2006-01-01

    Mg alloys exhibit a number of good properties such as low density, good castability and high specific strength.However, molten Mg and Mg alloys are ignited without the melt protective gases during melting and casting process due to their high reactivity.The purpose of this study is to investigate effects of Ca and CaO on pure Mg through microstructure observation, ignition test and phase analysis.With increasing Ca and CaO contents, the ignition resistance of Ca or CaO added pure Mg is increased and the grains are refined.As results of XRD and EDS, CaO is reduced to Ca in CaO added pure Mg.Mg2Ca phase is formed even in 0.1 wt.%CaO added pure Mg by reduction mechanism, while Mg2Ca phase is formed over 1.35 wt.% Ca added pure Mg.

  1. HADES RV Programme with HARPS-N at TNG. IV. Time resolved analysis of the Ca ii H&K and Hα chromospheric emission of low-activity early-type M dwarfs

    Science.gov (United States)

    Scandariato, G.; Maldonado, J.; Affer, L.; Biazzo, K.; Leto, G.; Stelzer, B.; Zanmar Sanchez, R.; Claudi, R.; Cosentino, R.; Damasso, M.; Desidera, S.; González Álvarez, E.; González Hernández, J. I.; Gratton, R.; Lanza, A. F.; Maggio, A.; Messina, S.; Micela, G.; Pagano, I.; Perger, M.; Piotto, G.; Rebolo, R.; Ribas, I.; Rosich, A.; Sozzetti, A.; Suárez Mascareño, A.

    2017-01-01

    Context. M dwarfs are prime targets for current and future planet search programs, particularly those focused on the detection and characterization of rocky planets in the habitable zone. In this context, understanding their magnetic activity is important for two main reasons: it affects our ability to detect small planets and it plays a key role in the characterization of the stellar environment. Aims: We analyze observations of the Ca ii H&K and Hα lines as diagnostics of chromospheric activity for low-activity early-type M dwarfs. Methods: We analyze the time series of spectra of 71 early-type M dwarfs collected in the framework of the HADES project for planet search purposes. The HARPS-N spectra simultaneously provide the Ca ii H&K doublet and the Hα line. We develop a reduction scheme able to correct the HARPS-N spectra for instrumental and atmospheric effects, and also to provide flux-calibrated spectra in units of flux at the stellar surface. The Ca ii H&K and Hα fluxes are then compared with each other, and their time variability is analyzed. Results: We find that the Ca ii H and K flux excesses are strongly correlated with each other, while the Hα flux excess is generally less correlated with the Ca ii H&K doublet. We also find that Hα emission does not increase monotonically with the Ca ii H&K line flux, showing some absorption before being filled in by chromospheric emission when Ca ii H&K activity increases. Analyzing the time variability of the emission fluxes, we derive a tentative estimate of the rotation period (on the order of a few tens of days) for some of the program stars, and the typical lifetime of chromospheric active regions (on the order of a few stellar rotations). Conclusions: Our results are in good agreement with similar previous studies. In particular, we find evidence that the chromospheres of early-type M dwarfs could be characterized by different filament coverage, affecting the formation mechanism of the Hα line. We also

  2. Study on Roasting Decomposition of Mixed Rare Earth Concentrate in CaO-NaCl-CaCl2

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The decomposed process of bastnaesite, monazite and mixed rare earth concentrate in CaO-CaCl-CaCl2 was studied by means of TG-DTA method. The relationship among decomposition ratio, roasting temperature, and CaO-NaCl addition was studied by the quadratic regression orthogonal analysis, and then the regression equation was obtained. Through analysis, the optimum process conditions of mixed rare earth concentrate decomposed by CaO-CaCl-CaCl2 were obtained as follows: roasting temperature: 700 ℃, CaO addition: 15%, NaCl-CaCl2 addition: 10%, roasting time: 60 min, the decomposition ratio: 91.3%.

  3. Regulated release of Ca2+ from respiring mitochondria by Ca2+/2H+ antiport.

    Science.gov (United States)

    Fiskum, G; Lehninger, A L

    1979-07-25

    Simultaneous measurements of oxygen consumption and transmembrane transport of Ca2+, H+, and phosphate show that the efflux of Ca2+ from respiring tightly coupled rat liver mitochondria takes place by an electroneutral Ca2+/2H+ antiport process that is ruthenium red-insensitive and that is regulated by the oxidation-reduction state of the mitochondrial pyridine nucleotides. When mitochondrial pyridine nucleotides are kept in a reduced steady state, the efflux of Ca2+ is inhibited; when they are in an oxidized state, Ca2+ efflux is activated. These processes were demonstrated by allowing phosphate-depleted mitochondria respiring on succinate in the presence of rotenone to take up Ca2+ from the medium. Upon subsequent addition of ruthenium red to block Ca2+ transport via the electrophoretic influx pathway, and acetoacetate, to bring mitochondrial pyridine nucleotides into the oxidized state, Ca2+ efflux and H+ influx ensued. The observed H+ influx/Ca2+ efflux ratio was close to the value 2.0 predicted for the operation of an electrically neutral Ca2+/2H+ antiport process.

  4. Prognostic significance of preoperative serum CA125, CA19-9 and CEA in gastric carcinoma

    Science.gov (United States)

    Wang, Wei; Chen, Xiao-Long; Zhao, Shen-Yu; Xu, Yu-Hui; Zhang, Wei-Han; Liu, Kai; Chen, Xin-Zu; Yang, Kun; Zhang, Bo; Chen, Zhi-Xin; Chen, Jia-Ping; Zhou, Zong-Guang; Hu, Jian-Kun

    2016-01-01

    The prognostic significance of preoperative serum CA125, CA19-9 and CEA in gastric carcinoma (GC) has been widely reported and is still under debate. Here, we evaluated the prognostic significance of preoperative serum CA125, CA19-9 and CEA in patients with GC. 1692 patients with GC who underwent gastrectomy were divided into the training (from January 2005 to December 2011, n = 1024) and the validation (from January 2012 to December 2013, n = 668) cohorts. Positive groups of CA125 (> 13.72 U/ml), CA19-9 (> 23.36 U/ml) and CEA (> 4.28 ng/ml) were significantly associated with more advanced clinicopathological traits and worse outcomes than that of negative groups (all P < 0.01). In Cox regression analysis, tumor size (P < 0.001, P = 0.005), pTNM stage (P < 0.001, P < 0.001) and CA125 (P = 0.026, P = 0.005) were independent prognostic factors both in two cohorts. Nomograms of these two cohorts based on the number of positive serum tumor markers (NPTM) were more accurate in prognostic prediction than TNM stage alone. Our findings suggested that elevated preoperative serum CA125, CA19-9 and CEA were associated with more advanced clinicopathological traits and less favorable outcomes. In addition, CA125 as an independent prognostic factor should be further investigated. Nomogram based on NPTM could accurately predict the prognosis of GC patients. PMID:27097114

  5. Aging and CaMKII Alter Intracellular Ca2+ Transients and Heart Rhythm in Drosophila melanogaster

    Science.gov (United States)

    Santalla, Manuela; Valverde, Carlos A.; Harnichar, Ezequiel; Lacunza, Ezequiel; Aguilar-Fuentes, Javier; Mattiazzi, Alicia; Ferrero, Paola

    2014-01-01

    Aging is associated to disrupted contractility and rhythmicity, among other cardiovascular alterations. Drosophila melanogaster shows a pattern of aging similar to human beings and recapitulates the arrhythmogenic conditions found in the human heart. Moreover, the kinase CaMKII has been characterized as an important regulator of heart function and an arrhythmogenic molecule that participate in Ca2+ handling. Using a genetically engineered expressed Ca2+ indicator, we report changes in cardiac Ca2+ handling at two different ages. Aging prolonged relaxation, reduced spontaneous heart rate (HR) and increased the occurrence of arrhythmias, ectopic beats and asystoles. Alignment between Drosophila melanogaster and human CaMKII showed a high degree of conservation and indicates that relevant phosphorylation sites in humans are also present in the fruit fly. Inhibition of CaMKII by KN-93 (CaMKII-specific inhibitor), reduced HR without significant changes in other parameters. By contrast, overexpression of CaMKII increased HR and reduced arrhythmias. Moreover, it increased fluorescence amplitude, maximal rate of rise of fluorescence and reduced time to peak fluorescence. These results suggest that CaMKII in Drosophila melanogaster acts directly on heart function and that increasing CaMKII expression levels could be beneficial to improve contractility. PMID:25003749

  6. EnviroAtlas - Fresno, CA - Block Groups

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset is the base layer for the Fresno, CA EnviroAtlas area. The block groups are from the US Census Bureau and are included/excluded based on...

  7. Distribution of CA 125 in placental tissues.

    Science.gov (United States)

    Fuith, L C; Müller-Holzner, E; Marth, C; Perkmann, E; Zeimet, A; Daxenbichler, G

    1989-01-01

    The presence of the tumor marker CA 125 was studied in different compartments of the human placenta. Levels of CA 125 in the cytosol of chorionic villi ranged from 27-17100 U/g (median 560 U/g). In the placental amnion and chorion concentrations ranged from 175-29000 U/g, median 1060 U/g and were not statistically different. In the umbilical cord values were significantly lower (range 44-7600 U/g; median 180 U/g). Maternal serum probes were above the upper limit of normal in all cases (range 48-500 U/ml; median 131 U/ml). Immunohistochemistry detected CA 125 exclusively within the amniotic cells of the placenta and the umbilical cord. This might be because CA 125 fixes more to insoluble structures in the amnion or because of contamination of chorionic villi with the underlying decidua.

  8. CaMath user`s guide

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Ben-chin; Daly, B.

    1994-07-13

    CaMath is an external Mathematica package which can be loaded into Mathematica by a user. CaMath consists of a special set of channel access functions which provides the Mathematica users with easy and flexible access of channel information across the IOC networks. It also provides a complete set of process variable event monitoring functions. The available functions for CaMath, their functionality, and their syntax are described herein. This document also gives examples how a Mathematica user can interface to channel access devices. It is assumed that the user is already familiar with using Mathematica. Few examples of Mathematica module of using CaMath functions are also given in this document.

  9. Ca2+/calmodulin-dependent kinase II contributes to inhibitor of nuclear factor-kappa B kinase complex activation in Helicobacter pylori infection.

    Science.gov (United States)

    Maubach, Gunter; Sokolova, Olga; Wolfien, Markus; Rothkötter, Hermann-Josef; Naumann, Michael

    2013-09-15

    Helicobacter pylori, a class I carcinogen, induces a proinflammatory response by activating the transcription factor nuclear factor-kappa B (NF-κB) in gastric epithelial cells. This inflammatory condition could lead to chronic gastritis, which is epidemiologically and biologically linked to the development of gastric cancer. So far, there exists no clear knowledge on how H. pylori induces the NF-κB-mediated inflammatory response. In our study, we investigated the role of Ca(2+) /calmodulin-dependent kinase II (CAMKII), calmodulin, protein kinases C (PKCs) and the CARMA3-Bcl10-MALT1 (CBM) complex in conjunction with H. pylori-induced activation of NF-κB via the inhibitor of nuclear factor-kappa B kinase (IKK) complex. We use specific inhibitors and/or RNA interference to assess the contribution of these components. Our results show that CAMKII and calmodulin contribute to IKK complex activation and thus to the induction of NF-κB in response to H. pylori infection, but not in response to TNF-α. Thus, our findings are specific for H. pylori infected cells. Neither the PKCs α, δ, θ, nor the CBM complex itself is involved in the activation of NF-κB by H. pylori. The contribution of CAMKII and calmodulin, but not PKCs/CBM to the induction of an inflammatory response by H. pylori infection augment the understanding of the molecular mechanism involved and provide potential new disease markers for the diagnosis of gastric inflammatory diseases including gastric cancer.

  10. CA Investment Casting Process of Complex Castings

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    CA (Computer aided) investment casting technique used in superalloy castings of aerospace engine parts was presented. CA investment casting integrated computer application, RP (Rapid Prototyping) process, solidification simulation and investment casting process. It broke the bottle neck of making metal die. Solid model of complex parts were produced by UGII or other software, then translated into STL(Stereolithography) file, after RP process of SLS(Selective Laser Sintering), wax pattern used in investment ...

  11. YouthCaN 2001 / Sirje Janikson

    Index Scriptorium Estoniae

    Janikson, Sirje

    2001-01-01

    Aprillis 2001 toimus keskkonnateemaline õpilaskonverents YouthCaN 2001 Ameerika Loodusajaloo Muuseumis New Yorkìs. 35 seminarist ühe viis läbi Tartu Noorte Loodusmaja geoloogia ja keskkonnaringi esindus, tutvustati loodusmaja keskkonnaprojekte ja räägiti keskkonnaalaste veebilehtede koostamise kogemustest. YouthCaN (Youth Communicating and Networking) on rahvusvaheline noorte organisatsioon, mis vahendab kogemusi ja uusi ideid elukeskkonnast huvitatud noorte hulgas

  12. PIK3CA in colorectal cancer

    Directory of Open Access Journals (Sweden)

    Gieri eCathomas

    2014-03-01

    Full Text Available PIK3CA, the catalytic subunit of PI3K, is mutated in many different tumours, including colorectal cancer. Mutations of PIK3CA have been reported in 10 – 20% of colorectal cancer, about 80% of mutations found in two hot spots in exon 9 and exon 20. In RAS wild-type colorectal cancers, PIK3CA mutations have been associated with a worse clinical outcome and with a negative prediction of a response to targeted therapy by anti-EGFR monoclonal antibodies. However, these findings have not been confirmed in all studies and subsequent more detailed analysis has revealed that these effects may be restricted to mutations in Exon 20. Finally, mutations in PIK3CA may be the long sought biomarker for successful adjuvant therapy with aspirin in patients with colorectal cancer. Therefore, PIK3CA mutations appear to be a promising predictive biomarker; however, further data are needed to conclusively define the impact of somatic mutations in the PIK3CA gene for the management of patients with colorectal cancer.

  13. Mitochondrial Ca2+ uptake in skeletal muscle health and disease

    CERN Document Server

    Zhou, Jingsong; Yi, Jianxun

    2016-01-01

    Muscle uses Ca2+ as a messenger to control contraction and relies on ATP to maintain the intracellular Ca2+ homeostasis. Mitochondria are the major sub-cellular organelle of ATP production. With a negative inner membrane potential, mitochondria take up Ca2+ from their surroundings, a process called mitochondrial Ca2+ uptake. Under physiological conditions, Ca2+ uptake into mitochondria promotes ATP production. Excessive uptake causes mitochondrial Ca2+ overload, which activates downstream adverse responses leading to cell dysfunction. Moreover, mitochondrial Ca2+ uptake could shape spatio-temporal patterns of intracellular Ca2+ signaling. Malfunction of mitochondrial Ca2+ uptake is implicated in muscle degeneration. Unlike non-excitable cells, mitochondria in muscle cells experience dramatic changes of intracellular Ca2+ levels. Besides the sudden elevation of Ca2+ level induced by action potentials, Ca2+ transients in muscle cells can be as short as a few milliseconds during a single twitch or as long as min...

  14. Phosphorylation at Ser²⁶ in the ATP-binding site of Ca²⁺/calmodulin-dependent kinase II as a mechanism for switching off the kinase activity.

    Science.gov (United States)

    Yilmaz, Mehtap; Gangopadhyay, Samudra S; Leavis, Paul; Grabarek, Zenon; Morgan, Kathleen G

    2013-02-07

    CaMKII (Ca²⁺/calmodulin-dependent kinase II) is a serine/threonine phosphotransferase that is capable of long-term retention of activity due to autophosphorylation at a specific threonine residue within each subunit of its oligomeric structure. The γ isoform of CaMKII is a significant regulator of vascular contractility. Here, we show that phosphorylation of CaMKII γ at Ser²⁶, a residue located within the ATP-binding site, terminates the sustained activity of the enzyme. To test the physiological importance of phosphorylation at Ser²⁶, we generated a phosphospecific Ser²⁶ antibody and demonstrated an increase in Ser²⁶ phosphorylation upon depolarization and contraction of blood vessels. To determine if the phosphorylation of Ser²⁶ affects the kinase activity, we mutated Ser²⁶ to alanine or aspartic acid. The S26D mutation mimicking the phosphorylated state of CaMKII causes a dramatic decrease in Thr²⁸⁷ autophosphorylation levels and greatly reduces the catalytic activity towards an exogenous substrate (autocamtide-3), whereas the S26A mutation has no effect. These data combined with molecular modelling indicate that a negative charge at Ser²⁶ of CaMKII γ inhibits the catalytic activity of the enzyme towards its autophosphorylation site at Thr²⁸⁷ most probably by blocking ATP binding. We propose that Ser²⁶ phosphorylation constitutes an important mechanism for switching off CaMKII activity.

  15. X-Ray Data on Extraterrestrial CA Dialuminate (CaAl4O7)

    Science.gov (United States)

    Weber, D.; Ross, C. R., II; Bischoff, A.

    1993-07-01

    After the first discovery of Ca-dialuminate (CaAl4O7) in Allende [1], in recent years this phase has been found in several carbonaceous chondrites. Ca- dialuminate is a major phase in Ca,Al-rich inclusions from ALH85085 (e.g., [2]) and a dominating phase in CAIs from Acfer 182 ([3,4]). X-ray data on Ca-dialuminate are known from synthetic (e.g., [5-8]; cell constants) and terrestrial CaAl4O7 ([9]; only d-spacings), but are not available from extraterrestrial Ca-dialuminate. We report here the results of the first X-ray study of extraterrestrial Ca- dialuminate. The data (Table 1) were obtained by microdiffraction using a Rigaku PSPC microdiffractometer at the Bayerisches Geoinstitut. Ni-filtered Cr radiation was used with a direct beam diameter of about 50 micrometers. This powder diffraction method allows in situ measurement of polycrystalline Ca- dialuminate in a thin section. The CaAl4O7-rich inclusion 022/9 described in [4], consisting of a ~200-micrometer-sized core of Ca-dialuminate surrounded by layers of melilite and Ca-pyroxene, was chosen for analysis. The polycrystalline core contains only a small number of tiny inclusions (especially perovskite) and is therefore an excellent candidate for an X-ray study. For determination of the d-spacings of Ca-dialuminate an external standard (Ag6Ge10P12) was used for detector calibration. A large number of reflections could be indexed based upon comparison with the X-ray pattern of synthetic CaAl4O7 available in the JCPDS compilation [7]. The comparison was simplified because of the high purity of CaAl4O7 in inclusion 022/9 [4], and suggests the same structure for synthetic and extraterrestrial Ca-dialuminate. For determination of lattice parameters (cell constants, cell volume) refinement calculations were made based on 14 reflections (Table 1). The data for extraterrestrial CaAl4O7 shown in Table 1 indicate a close similarity to those obtained for synthetic CaAl4O7. The cell constants a, b, and therefore the cell

  16. Sarcolemmal Ca(2+)-entry through L-type Ca(2+) channels controls the profile of Ca(2+)-activated Cl(-) current in canine ventricular myocytes.

    Science.gov (United States)

    Horváth, Balázs; Váczi, Krisztina; Hegyi, Bence; Gönczi, Mónika; Dienes, Beatrix; Kistamás, Kornél; Bányász, Tamás; Magyar, János; Baczkó, István; Varró, András; Seprényi, György; Csernoch, László; Nánási, Péter P; Szentandrássy, Norbert

    2016-08-01

    Ca(2+)-activated Cl(-) current (ICl(Ca)) mediated by TMEM16A and/or Bestrophin-3 may contribute to cardiac arrhythmias. The true profile of ICl(Ca) during an actual ventricular action potential (AP), however, is poorly understood. We aimed to study the profile of ICl(Ca) systematically under physiological conditions (normal Ca(2+) cycling and AP voltage-clamp) as well as in conditions designed to change [Ca(2+)]i. The expression of TMEM16A and/or Bestrophin-3 in canine and human left ventricular myocytes was examined. The possible spatial distribution of these proteins and their co-localization with Cav1.2 was also studied. The profile of ICl(Ca), identified as a 9-anthracene carboxylic acid-sensitive current under AP voltage-clamp conditions, contained an early fast outward and a late inward component, overlapping early and terminal repolarizations, respectively. Both components were moderately reduced by ryanodine, while fully abolished by BAPTA, but not EGTA. [Ca(2+)]i was monitored using Fura-2-AM. Setting [Ca(2+)]i to the systolic level measured in the bulk cytoplasm (1.1μM) decreased ICl(Ca), while application of Bay K8644, isoproterenol, and faster stimulation rates increased the amplitude of ICl(Ca). Ca(2+)-entry through L-type Ca(2+) channels was essential for activation of ICl(Ca). TMEM16A and Bestrophin-3 showed strong co-localization with one another and also with Cav1.2 channels, when assessed using immunolabeling and confocal microscopy in both canine myocytes and human ventricular myocardium. Activation of ICl(Ca) in canine ventricular cells requires Ca(2+)-entry through neighboring L-type Ca(2+) channels and is only augmented by SR Ca(2+)-release. Substantial activation of ICl(Ca) requires high Ca(2+) concentration in the dyadic clefts which can be effectively buffered by BAPTA, but not EGTA.

  17. Endothelin-1 induces intracellular [Ca2+] increase via Ca2+ influx through the L-type Ca2+ channel, Ca2+-induced Ca2+ release and a pathway involving ETA receptors, PKC, PKA and AT1 receptors in cardiomyocytes

    Institute of Scientific and Technical Information of China (English)

    ZENG QingHua; LI XingTing; ZHONG GuoGan; ZHANG WenJie; SUN ChengWen

    2009-01-01

    Using fura-2-acetoxymethyl eater (AM) fluorescence imaging and patch clamp techniques, we found that endothelin-1 (ET-1) significantly elevated the intracellular calcium level ([Ca2+]1) in a dose-dependent manner and activated the L-type Ca2+ channel in cardiomyocytes isolated from rats.The effect of ET-1 on [Ca2+]1 elevation was abolished in the presence of the ETA receptor blocker BQ123,but was not affected by the ETa receptor blocker BQ788. ET-1-induced an increase in [Ca2+]1, which was inhibited 46.7% by pretreatment with a high concentration of ryanodine (10 μmol/L), a blocker of the ryanodine receptor. The ET-1-induced [Ca2+]i increase was also inhibited by the inhibltors of protein kinase A (PKA), protein kinase C (PKC) and angiotensin type 1 receptor (AT1 receptor). We found that ET-1 induced an enhancement of the amplitude of the whole cell L-type Ca2+ channel current and an Increase of open-state probability (NPo) of an L-type single Ca2+ channel. BQ123 completely blocked the ET-1-induced increase in calcium channel open-state probability. In this study we demonstrated that ET-1 regulates calcium overload through a series of mechanisms that include L-type Ca2+ channel activation and Ca2+-induced Ca2+ release (CICR). ETa receptors, PKC, PKA and AT1 receptors may also contribute to this pathway.

  18. Endothelin-1 induces intracellular [Ca2+] increase via Ca2+ influx through the L-type Ca2+ channel, Ca2+-induced Ca2+ release and a pathway involving ETA receptors, PKC, PKA and AT1 receptors in cardiomyocytes

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Using fura-2-acetoxymethyl ester (AM) fluorescence imaging and patch clamp techniques, we found that endothelin-1 (ET-1) significantly elevated the intracellular calcium level ([Ca2+]i) in a dose-dependent manner and activated the L-type Ca2+ channel in cardiomyocytes isolated from rats. The effect of ET-1 on [Ca2+]i elevation was abolished in the presence of the ETA receptor blocker BQ123, but was not affected by the ETB receptor blocker BQ788. ET-1-induced an increase in [Ca2+]i, which was inhibited 46.7% by pretreatment with a high concentration of ryanodine (10 μmol/L), a blocker of the ryanodine receptor. The ET-1-induced [Ca2+]i increase was also inhibited by the inhibitors of protein kinase A (PKA), protein kinase C (PKC) and angiotensin type 1 receptor (AT1 receptor). We found that ET-1 induced an enhancement of the amplitude of the whole cell L-type Ca2+ channel current and an increase of open-state probability (NPo) of an L-type single Ca2+ channel. BQ123 completely blocked the ET-1-induced increase in calcium channel open-state probability. In this study we demonstrated that ET-1 regulates calcium overload through a series of mechanisms that include L-type Ca2+ channel activation and Ca2+-induced Ca2+ release (CICR). ETA receptors, PKC, PKA and AT1 receptors may also contribute to this pathway.

  19. Mitochondrial calcium uniporter MCU supports cytoplasmic Ca2+ oscillations, store-operated Ca2+ entry and Ca2+-dependent gene expression in response to receptor stimulation.

    Science.gov (United States)

    Samanta, Krishna; Douglas, Sophie; Parekh, Anant B

    2014-01-01

    Ca2+ flux into mitochondria is an important regulator of cytoplasmic Ca2+ signals, energy production and cell death pathways. Ca2+ uptake can occur through the recently discovered mitochondrial uniporter channel (MCU) but whether the MCU is involved in shaping Ca2+ signals and downstream responses to physiological levels of receptor stimulation is unknown. Here, we show that modest stimulation of leukotriene receptors with the pro-inflammatory signal LTC4 evokes a series of cytoplasmic Ca2+ oscillations that are rapidly and faithfully propagated into mitochondrial matrix. Knockdown of MCU or mitochondrial depolarisation, to reduce the driving force for Ca2+ entry into the matrix, prevents the mitochondrial Ca2+ rise and accelerates run down of the oscillations. The loss of cytoplasmic Ca2+ oscillations appeared to be a consequence of enhanced Ca2+-dependent inactivation of InsP3 receptors, which arose from the loss of mitochondrial Ca2+ buffering. Ca2+ dependent gene expression in response to leukotriene receptor activation was suppressed following knockdown of the MCU. In addition to buffering Ca2+ release, mitochondria also sequestrated Ca2+ entry through store-operated Ca2+ channels and this too was prevented following loss of MCU. MCU is therefore an important regulator of physiological pulses of cytoplasmic Ca2+.

  20. Mitochondrial calcium uniporter MCU supports cytoplasmic Ca2+ oscillations, store-operated Ca2+ entry and Ca2+-dependent gene expression in response to receptor stimulation.

    Directory of Open Access Journals (Sweden)

    Krishna Samanta

    Full Text Available Ca2+ flux into mitochondria is an important regulator of cytoplasmic Ca2+ signals, energy production and cell death pathways. Ca2+ uptake can occur through the recently discovered mitochondrial uniporter channel (MCU but whether the MCU is involved in shaping Ca2+ signals and downstream responses to physiological levels of receptor stimulation is unknown. Here, we show that modest stimulation of leukotriene receptors with the pro-inflammatory signal LTC4 evokes a series of cytoplasmic Ca2+ oscillations that are rapidly and faithfully propagated into mitochondrial matrix. Knockdown of MCU or mitochondrial depolarisation, to reduce the driving force for Ca2+ entry into the matrix, prevents the mitochondrial Ca2+ rise and accelerates run down of the oscillations. The loss of cytoplasmic Ca2+ oscillations appeared to be a consequence of enhanced Ca2+-dependent inactivation of InsP3 receptors, which arose from the loss of mitochondrial Ca2+ buffering. Ca2+ dependent gene expression in response to leukotriene receptor activation was suppressed following knockdown of the MCU. In addition to buffering Ca2+ release, mitochondria also sequestrated Ca2+ entry through store-operated Ca2+ channels and this too was prevented following loss of MCU. MCU is therefore an important regulator of physiological pulses of cytoplasmic Ca2+.

  1. Heat and hyposmotic stimulation increase in [Ca2+]i by Ca2+ influx in rat synoviocytes

    Institute of Scientific and Technical Information of China (English)

    SUN WenWu; HU Fen; YANG WenXiu

    2008-01-01

    Rheumatoid arthritis (RA), which is marked by inflammatory synovitis, is a common, chronic autoimmune-disease, whose pathogenesis is complex and still unclear. In order to explore the effects of heat and hyposmotic stimuli on synoviocytes in rheumatoid arthritis, the changes of [Ca2+]i induced by heat, hyposmotic and 4α-PDD stimuli were observed in synoviocytes. [Ca2+]i elevation induced by heat ≥ 28℃, hyposmotic and 4α-PDD stimuli is found to be positively relative to increasing temperature, decreasing osmolality and rising concentration of 4α-PDD. Results show that there is reciprocity among these stimuli and desensitization, and that [Ca2+]i elevation depends on Ca2+ influx, but not necessarily links to Ca2+ release from intracellular stores and voltage-dependent Ca2+ channel in synoviocytes. The above characteristics of Ca2+ influx are similar to those of TRPV4. A probable mechanism has been suggested that heat and hyposmotic stimulation might increase the level of [Ca2+]i by activating the TRPV4-like channel and Ca2+ influx in the synoviocytes.

  2. Relationship Between Ca2+-CaM and Ethylene-Induced PG Activity in Tomato Fruit

    Institute of Scientific and Technical Information of China (English)

    GU Cai-qin; XI Yu-fang; GUAN Jun-feng; LI Guang-min

    2003-01-01

    Polygalacturonase (PG) was studied during ripening and senescence of postharvest tomatofruit at pink stage at low and normal temperature. The results showed that the PG activity increased, thendecreased during ripening and senescence of tomato. Low temperature inhibited but ethylene enhanced PGactivity. Ethylene also enhanced caimodulin content, which was dependent on Ca2+ concentration in cell.When EGTA(Ca2+ chelator), verapamil (Vp) and LaCl3 (Ca2+ channel blockers), trifluoperazine and chloro-promaize (two CaM antagonisms) were used to treat tomato fruit at green mature stage with ethylene, theycould reverse ethylene-induced increase in PG activity, but Vp, chloropromaize (CPZ), trifluoperazine(TFP) could not directly influence PG activity, which indirectly indicated that influx of Ca2+ from the ex-tracellular space including the cell wall via the Ca2+ channel localized in plasma membrane and CaM were re-quired for ethylene-induced PG activity increase and that ethylene signal transduction may be related to Ca2+- CaM messenger system.

  3. Novel nootropic drug sunifiram improves cognitive deficits via CaM kinase II and protein kinase C activation in olfactory bulbectomized mice.

    Science.gov (United States)

    Moriguchi, Shigeki; Tanaka, Tomoya; Tagashira, Hideaki; Narahashi, Toshio; Fukunaga, Kohji

    2013-04-01

    Alzheimer's disease (AD) shows degeneration of the cholinergic system in the medial septum, thereby eliciting down-regulation of the olfactory function in patients. We have previously reported that olfactory bulbectomized (OBX) mice show hippocampus-dependent memory impairment as assessed by memory-related behavioral tasks and hippocampal long-term potentiation (LTP). In the present study, we focused whether novel pyrrolidone nootropic drug sunifiram improves both memory impairment and depression observed in OBX mice. OBX mice were administered once a day for 7-12 days with sunifiram (0.01-1.0mg/kg p.o.) from 10 days after operation with or without gavestinel (10mg/kg i.p.), which is glycine-binding site inhibitor of N-methyl-d-aspartate receptor (NMDAR). The spatial reference memory assessed by Y-maze and short-term memory assessed by novel object recognition task were significantly improved by sunifiram treatment in OBX mice. Sunifiram also restored hippocampal LTP injured in OBX mice without treatment with gavestinel. By contrast, sunifiram treatment did not ameliorate the depressive behaviors assessed by tail suspension task in OBX mice. Notably, sunifiram treatment restored CaMKIIα (Thr-286) autophosphorylation and GluR1 (Ser-831) phosphorylation in the hippocampal CA1 region from OBX mice to the levels of control mice. Likewise, sunifiram treatment improved PKCα (Ser-657) autophosphorylation and NR1 (Ser-896) phosphorylation to the control levels. Stimulation of CaMKII and PKC autophosphorylation by sunifiram was significantly inhibited by pre-treatment with gavestinel. However, sunifiram treatment did not affect the phosphorylation of CaMKIV (Thr-196) and ERK. Taken together, sunifiram ameliorates OBX-induced deficits of memory-related behaviors and impaired LTP in the hippocampal CA1 region via stimulation of glycine-binding site of NMDAR.

  4. Synthetic CA II Triplet Lines

    Science.gov (United States)

    Erdelyi, M. M.; Barbuy, B.

    1990-11-01

    RESUMEN. Se hicieron calculos de sintesis del espectro en el ititervalo de longitud de onda - 8700 A, ara ? oder verificar el comporta- mien to de diferentes lineas moleculares y at5micas como funci5n de los parametros esteldres de temperatura, gravedad y metalicidad. El espec- tro sintetico ha sido generado para:(a) todas las , (b) solamente de CN, (c) solamente de TiO, y (d) solamente lineas at6micas. Abstract. Spectrum synthesis calculations are carried out in the wavelength interval X 8300 - 8700 A, in order to verify the behaviour of different molecular and atomic lines as a function of the stellar para meters temperature, gravity and metallicity. Synthetic spectra were ge nerated for: (a) all lines, (b) only CN lines, (c) only TiO lines, and (d) only atomic lines Key `td6: LINE-PROFILE - ST S-AThOSPHERES

  5. CaCl2-CaO熔盐中金属钙的电沉积行为研究

    Institute of Scientific and Technical Information of China (English)

    郭君康

    2014-01-01

    在900℃下,采用循环伏安法对CaCl2-CaO熔盐中金属钙的电沉积行为进行了研究.研究结果表明,在CaCl2熔盐中加入CaO后,熔盐中Ca2+的还原电位正移,且Ca2+的还原过程受扩散控制.

  6. Tolerância de genótipos de cafeeiro ao alumínio em solução nutritiva. II. Teores de P, Ca e Al e eficiência ao P e Ca

    Directory of Open Access Journals (Sweden)

    M. C. L. Braccini

    1998-09-01

    Full Text Available Foi instalado um experimento, em janeiro de 1994, em casa de vegetação do Departamento de Fitotecnia da Universidade Federal de Viçosa, Estado de Minas Gerais. Com o objetivo de avaliar o efeito do alumínio nos teores de P, Ca e Al e na eficiência ao fósforo e cálcio de nove genótipos de café, as plantas foram crescidas em solução nutritiva com 0 e 0,296 mmol L-1 de alumínio, com pH 4,0, por um período de 115 dias. Após esse período, as plantas foram divididas em folhas superiores, folhas inferiores, primeiro par de folhas totalmente expandido, caule e raízes, para a determinação da matéria seca e de concentrações de fósforo, cálcio e alumínio. A tolerância ao alumínio foi associada ao menor acúmulo de fósforo nas raízes, à menor redução na translocação desse nutriente para a parte aérea, à menor redução na absorção de cálcio e à maior eficiência no uso do fósforo e do cálcio. Foi observado grande acúmulo de alumínio nas raízes, bem como um transporte restrito do elemento para a parte aérea, para todos os genótipos de café.

  7. Diffusion of Ca and Mg in Calcite

    Energy Technology Data Exchange (ETDEWEB)

    Cygan, R.T.; Fisler, D.K.

    1999-02-10

    The self-diffusion of Ca and the tracer diffusion of Mg in calcite have been experimentally measured using isotopic tracers of {sup 25}Mg and {sup 44}Ca. Natural single crystals of calcite were coated with a thermally-sputtered oxide thin film and then annealed in a CO{sub 2} gas at one atmosphere total pressure and temperatures from 550 to 800 C. Diffusion coefficient values were derived from the depth profiles obtained by ion microprobe analysis. The resultant activation energies for Mg tracer diffusion and Ca self-diffusion are respectively: E{sub a}(Mg) = 284 {+-} 74 kJ/mol and E{sub a}(Ca) = 271 {+-} 80 kJ/mol. For the temperature ranges in these experiments, the diffusion of Mg is faster than Ca. The results are generally consistent in magnitude with divalent cation diffusion rates obtained in previous studies and provide a means of interpreting the thermal histories of carbonate minerals, the mechanism of dolomitization, and other diffusion-controlled processes. The results indicate that cation diffusion in calcite is relatively slow and cations are the rate-limiting diffusing species for the deformation of calcite and carbonate rocks. Application of the calcite-dolomite geothermometer to metamorphic assemblages will be constrained by cation diffusion and cooling rates. The direct measurement of Mg tracer diffusion in calcite indicates that dolomitization is unlikely to be accomplished by Mg diffusion in the solid state but by a recrystallization process.

  8. Treatment of Ruptured Ovarian Endometrioma with Extremely High CA 125, Moderately High CA 19-9 and CA 15-3 Level

    Directory of Open Access Journals (Sweden)

    Muzeyyen Duran

    2013-06-01

    Full Text Available In this case report, a ruptured ovarian endometrioma with a very high CA-125 level, moderately elevated CA 19-9, and CA 15-3 levels is presented. A 20 years old patient, complaining from pelvic pain, 5 cm adnexial mass was detected on left side. Biochemical examination was revealed very high CA-125 value (2556IU/ml, moderately elevated CA 19-9 (134IU/ml, and CA 15-3 (65IU/ml values. Laparoscopy was done and a ruptured ovarian endometrioma of 5 cm was seen during operation. After the total excision of the cyst, tumor markers fell rapidly. Very high CA-125 value, moderately elevated CA19-9, and CA 15-3 values can be seen in cases with ruptured endometrioma. In young patients, endometrioma must be considered firstly and laparoscopy should be applied instead of more invasive methods unless there was any finding or strong suspicion about malignancy.

  9. Control of ciliary motility by Ca sup 2+ : Integration of Ca sup 2+ -dependent functions and targets for Ca sup 2+ action

    Energy Technology Data Exchange (ETDEWEB)

    Evans, T.C.

    1988-01-01

    To identify functions that regulate Ca{sup 2+}-induced ciliary reversal in Paramecium, mutants defective in terminating depolarization-induced backward swimming were selected. Six independent recessive mutations (k-shy) comprising two complementation groups, k-shyA and k-shyB, were identified. All mutants exhibited prolonged backward swimming in depolarizing solutions. Voltage clamp studies revealed that mutant Ca{sup 2+} current amplitudes were reduced, but could be restored to wild type levels by EGTA injection. The recovery of the mutant Ca{sup 2+} current from Ca{sup 2+}-dependent inactivation, and the decay of the Ca{sup 2+}-dependent K{sup +} and Ca{sup 2+}-dependent Na{sup +} currents after depolarization were slow in k-shy compared to wild type. To identify protein targets of Ca{sup 2+} action, ciliary proteins that interact with calmodulin (CaM) were characterized. With a {sup 125}I-CaM blot assay, several CaM-binding proteins were identified including axonemal, soluble, and membrane-bound polypeptides. Competitive displacement studies with unlabeled Paramecium CaM, bovine CaM, and troponinC suggested that both protein types bind CaM with high affinity and specificity. To examine the presence of CaM-binding sites in intact axonemes, a filtration binding assay was developed.

  10. Clinical significance of detecting CEA, CA199, AFP, HCG, CA153, CA125 in postoperative treatment of patients with ovarian cancer

    Institute of Scientific and Technical Information of China (English)

    Xue Pan; Zhen-Hua Du

    2016-01-01

    Objective:To explore the clinical significance of carcinoembryonic antigen (CEA), carbohydrate antigen 199 (CA199), a tire protein (AFP), human chorionic gonadotropin (HCG), carbohydrate antigen 153 (CA153) and carbohydrate antigen 125 (CA125) in the postoperative treatment of patients with ovarian cancer.Methods:210 cases of patients with ovarian cancer after initial treatment from January 2015 to December 2015, 232 cases of patients with ovarian benign tumor and 250 cases of healthy women were selected, CEA, CA199, AFP, HCG, CA153 and CA125 levels were detected, and the levels after chemotherapy in patients with ovarian carcinoma were detected.Results:CEA, CA199, AFP, HCG, CA153 and CA125 levels in patients with ovarian cancer were (12.37±7.43) ng/mL, (84.04±26.96) U/mL, (37.46±9.47) μg/L, (110.54±35.51) IU/L, (51.23±9.20) U/mL and (64.36±42.68) U/mL, respectively, which were significantly higher than that in normal controls and patients with benign ovarian lesions, and were considered to be statistically significant. Chemotherapy after two cycles, CEA, CA199, AFP, HCG, CA153 and CA125 levels in patients with ovarian cancer were significantly lower than that before chemotherapy, and were considered to be statistically different. Chemotherapy after four cycles, CEA, CA199, AFP, HCG, CA153 and CA125 levels in patients with ovarian cancer continue to decrease, and were significantly lower than that of chemotherapy after two cycles, and had statistical differences.Conclusion:CEA, CA199, AFP, HCG, CA153 and CA125 can be used as important indicators for monitoring the chemotherapy effects, early recurrence and metastasis of ovarian cancer.

  11. Synaptotagmin-7 is a principal Ca2+ sensor for Ca2+ -induced glucagon exocytosis in pancreas

    DEFF Research Database (Denmark)

    Gustavsson, Natalia; Wei, Shun-Hui; Hoang, Dong Nhut

    2009-01-01

    abolished Ca(2+)-triggered glucagon secretion. Moreover, single-cell capacitance measurements confirmed that pancreatic alpha-cells lacking synaptotagmin-7 exhibited little Ca(2+)-induced exocytosis, whereas all other physiological and morphological parameters of the alpha-cells were normal. Our data thus...

  12. Investigation of the 42Ca(n, γ)43Ca reaction

    NARCIS (Netherlands)

    Gruppelaar, H.; Kamp, A.M.F. op den; Spits, A.M.J.

    1969-01-01

    Gamma rays from thermal-neutron capture in enriched 42Ca were investigated with Ge(Li) detectors. Gamma-gamma coincidence measurements were performed with a Ge(Li)---NaI detector combination. A decay scheme of 43Ca has been constructed containing 42 of the 47 observed γ-lines. The excitation energie

  13. Sulfide capacity of CaO-CaF2-SiO2 slags

    Science.gov (United States)

    Susaki, Katsujiro; Maeda, Masafumi; Sano, Nobuo

    1990-02-01

    The sulfide capacity C S 2- = (pct S2-) · ( P O 2/ P S 2)1/2) of CaO-CaF2-SiO2 slags saturated with CaO, 3CaO · SiO2 or 2CaOSiO2 was determined at 1200 °C, 1250 °C, 1300 °C, and 1350 °C by equilibrating molten slag, molten silver, and CO-CO2 gas mixtures. Higher sulfide capacities were obtained for CaO-saturated slags. A drastic decrease was observed in those values when the ratio pct CaO/pct SiO2 is less than 2. The sulfur partition between carbon-saturated iron melts and presently investigated slags was calculated by using the sulfide capacities obtained and the activity coefficient of sulfur in carbon-saturated iron, which was also experimentally determined. For slags saturated with CaO, partitions of sulfur as high as 10,000 were obtained at 1300 °C and 1350 °C. Correlations between the sulfide capacity and other basicity indexes such as carbonate capacity and theoretical optical basicity were also discussed.

  14. Multifaceted plasma membrane Ca(2+) pumps: From structure to intracellular Ca(2+) handling and cancer.

    Science.gov (United States)

    Padányi, Rita; Pászty, Katalin; Hegedűs, Luca; Varga, Karolina; Papp, Béla; Penniston, John T; Enyedi, Ágnes

    2016-06-01

    Plasma membrane Ca(2+) ATPases (PMCAs) are intimately involved in the control of intracellular Ca(2+) concentration. They reduce Ca(2+) in the cytosol not only by direct ejection, but also by controlling the formation of inositol-1,4,5-trisphosphate and decreasing Ca(2+) release from the endoplasmic reticulum Ca(2+) pool. In mammals four genes (PMCA1-4) are expressed, and alternative RNA splicing generates more than twenty variants. The variants differ in their regulatory characteristics. They localize into highly specialized membrane compartments and respond to the incoming Ca(2+) with distinct temporal resolution. The expression pattern of variants depends on cell type; a change in this pattern can result in perturbed Ca(2+) homeostasis and thus altered cell function. Indeed, PMCAs undergo remarkable changes in their expression pattern during tumorigenesis that might significantly contribute to the unbalanced Ca(2+) homeostasis of cancer cells. This article is part of a Special Issue entitled: Calcium and Cell Fate. Guest Editors: Jacques Haiech, Claus Heizmann, Joachim Krebs, Thierry Capiod and Olivier Mignen.

  15. Ca3Mn2O7.

    Science.gov (United States)

    Guiblin, Nicolas; Grebille, Dominique; Leligny, Henri; Martin, Christine

    2002-01-01

    The tricalcium dimanganese heptaoxide (Ca3Mn2O7) member of the Ruddlesden-Popper series Ca(n+1)Mn(n)O(3n+1), i.e. with n = 2, was previously reported with an I-centred tetragonal lattice [a(t) = 3.68 and c(t) = 19.57 A] by Fawcett, Sunstrom, Greenblatt, Croft & Ramanujachary [Chem. Mater. (1998), 10, 3643-3651]. It is now found to be orthorhombic, with an A-centred lattice [a = 5.2347 (6), b = 5.2421 (2) and c = 19.4177 (19) A]. The structure has been refined in space group A2(1)am using X-ray single-crystal diffraction data and assuming the existence of twin domains related by the (1-10) plane. A comparison with the basic perovskite structure CaMnO3 (n = infinity) is proposed.

  16. Calcium platinum aluminium, CaPtAl

    Directory of Open Access Journals (Sweden)

    Charles Fon Abi

    2011-10-01

    Full Text Available A preliminary X-ray study of CaPtAl has been reported previously by Hulliger [J. Alloys Compd (1993, 196, 225–228] based on X-ray powder diffraction data without structure refinement. With the present single-crystal X-ray study, we confirm the assignment of the TiNiSi type for CaPtAl, in a fully ordered inverse structure. All three atoms of the asymmetric unit have .m. site symmetry. The structure features a ∞3[AlPt] open framework with a fourfold coordination of Pt by Al atoms and vice versa. The Ca atoms are located in the large channels of the structure.

  17. Atom Trap Trace Analysis of Ca Isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Hoekstra, S., E-mail: hoekstra@fhi-berlin.mgp.de [Fritz-Haber Institut der Max-Planck Gesellschaft (Germany); Mollema, A. K.; Morgenstern, R.; Willmann, L.; Wilschut, H. W.; Hoekstra, R. [Rijksuniversiteit Groningen, Atomic Physics, KVI (Netherlands)

    2005-04-15

    In our experiment we aim at the detection of the rarest, naturally occuring calcium isotope 41Ca by means of atom trap trace analysis. On basis of single-atom detection of 46Ca our present sensitivity for 41Ca is estimated to be 1 atom per hour at an abundance of 10-12. To reach a sensitivity at the level of natural abundance, which is 10-14, we need to reduce atomic beam losses. To achieve this, optical compression of the atomic beam is a promising option. We use Monte Carlo Simulations to demonstrate that optical compression of the atomic beam increases throughput of the atomic beam as well as isotope selectivity.

  18. ASteCA - Automated Stellar Cluster Analysis

    CERN Document Server

    Perren, Gabriel I; Piatti, Andrés E

    2014-01-01

    We present ASteCA (Automated Stellar Cluster Analysis), a suit of tools designed to fully automatize the standard tests applied on stellar clusters to determine their basic parameters. The set of functions included in the code make use of positional and photometric data to obtain precise and objective values for a given cluster's center coordinates, radius, luminosity function and integrated color magnitude, as well as characterizing through a statistical estimator its probability of being a true physical cluster rather than a random overdensity of field stars. ASteCA incorporates a Bayesian field star decontamination algorithm capable of assigning membership probabilities using photometric data alone. An isochrone fitting process based on the generation of synthetic clusters from theoretical isochrones and selection of the best fit through a genetic algorithm is also present, which allows ASteCA to provide accurate estimates for a cluster's metallicity, age, extinction and distance values along with its unce...

  19. Anoxia-induced elevation of cytosolic Ca2+ concentration depends on different Ca2+ sources in rice and wheat protoplasts.

    Science.gov (United States)

    Yemelyanov, Vladislav V; Shishova, Maria F; Chirkova, Tamara V; Lindberg, Sylvia M

    2011-08-01

    The anoxia-dependent elevation of cytosolic Ca(2+) concentration, [Ca(2+)](cyt), was investigated in plants differing in tolerance to hypoxia. The [Ca(2+)](cyt) was measured by fluorescence microscopy in single protoplasts loaded with the calcium-fluoroprobe Fura 2-AM. Imposition of anoxia led to a fast (within 3 min) significant elevation of [Ca(2+)](cyt) in rice leaf protoplasts. A tenfold drop in the external Ca(2+) concentration (to 0.1 mM) resulted in considerable decrease of the [Ca(2+)](cyt) shift. Rice root protoplasts reacted upon anoxia with higher amplitude. Addition of plasma membrane (verapamil, La(3+) and EGTA) and intracellular membrane Ca(2+)-channel antagonists (Li(+), ruthenium red and cyclosporine A) reduced the anoxic Ca(2+)-accumulation in rice. Wheat protoplasts responded to anoxia by smaller changes of [Ca(2+)](cyt). In wheat leaf protoplasts, the amplitude of the Ca(2+)-shift little depended on the external level of Ca(2+). Wheat root protoplasts were characterized by a small shift of [Ca(2+)](cyt) under anoxia. Plasmalemma Ca(2+)-channel blockers had little effect on the elevation of cytosolic Ca(2+) in wheat protoplasts. Intact rice seedlings absorbed Ca(2+) from the external medium under anoxic treatment. On the contrary, wheat seedlings were characterized by leakage of Ca(2+). Verapamil abolished the Ca(2+) influx in rice roots and Ca(2+) efflux from wheat roots. Anoxia-induced [Ca(2+)](cyt) elevation was high particularly in rice, a hypoxia-tolerant species. In conclusion, both external and internal Ca(2+) stores are important for anoxic [Ca(2+)](cyt) elevation in rice, whereas the hypoxia-intolerant wheat does not require external sources for [Ca(2+)](cyt) rise. Leaf and root protoplasts similarly responded to anoxia, independent of their organ origin.

  20. Mitochondrial Ca(2+) uptake in skeletal muscle health and disease.

    Science.gov (United States)

    Zhou, Jingsong; Dhakal, Kamal; Yi, Jianxun

    2016-08-01

    Muscle uses Ca(2+) as a messenger to control contraction and relies on ATP to maintain the intracellular Ca(2+) homeostasis. Mitochondria are the major sub-cellular organelle of ATP production. With a negative inner membrane potential, mitochondria take up Ca(2+) from their surroundings, a process called mitochondrial Ca(2+) uptake. Under physiological conditions, Ca(2+) uptake into mitochondria promotes ATP production. Excessive uptake causes mitochondrial Ca(2+) overload, which activates downstream adverse responses leading to cell dysfunction. Moreover, mitochondrial Ca(2+) uptake could shape spatio-temporal patterns of intracellular Ca(2+) signaling. Malfunction of mitochondrial Ca(2+) uptake is implicated in muscle degeneration. Unlike non-excitable cells, mitochondria in muscle cells experience dramatic changes of intracellular Ca(2+) levels. Besides the sudden elevation of Ca(2+) level induced by action potentials, Ca(2+) transients in muscle cells can be as short as a few milliseconds during a single twitch or as long as minutes during tetanic contraction, which raises the question whether mitochondrial Ca(2+) uptake is fast and big enough to shape intracellular Ca(2+) signaling during excitation-contraction coupling and creates technical challenges for quantification of the dynamic changes of Ca(2+) inside mitochondria. This review focuses on characterization of mitochondrial Ca(2+) uptake in skeletal muscle and its role in muscle physiology and diseases.

  1. {sup 48}Ca HETEROGENEITY IN DIFFERENTIATED METEORITES

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hsin-Wei; Lee, Typhoon; Lee, Der-Chuen; Shen, Jason Jiun-San; Chen, Jiang-Chang, E-mail: haart@earth.sinica.edu.tw [Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan (China)

    2011-12-10

    Isotopic heterogeneities of {sup 48}Ca have been found in numerous bulk meteorites that are correlated with {sup 50}Ti and {sup 54}Cr anomalies among differentiated planetary bodies, and the results suggest that a rare subset of neutron-rich Type Ia supernova (nSN Ia) was responsible for contributing these neutron-rich iron-group isotopes into the solar system (SS). The heterogeneity of these isotopes found in differentiated meteorites indicates that the isotopic compositions of the bulk SS are not uniform, and there are significant amounts of nSNe Ia dust incompletely mixed with the rest of SS materials during planetary formation. Combined with the data of now-extinct short-lived nuclide {sup 60}Fe, which can be produced more efficiently from an nSN Ia than a Type II supernova ejecta, the observed planetary-scale isotopic heterogeneity probably reflects a late input of stellar dust grains with neutron-rich nuclear statistical equilibrium nuclides into the early SS.

  2. Electrochemical formation of Mg-Li-Ca alloys by codeposition of Mg, Li and Ca from LiCl-KCl-MgCl2-CaCl2 melts.

    Science.gov (United States)

    Yan, Yong De; Zhang, Mi Lin; Xue, Yun; Han, Wei; Cao, Dian Xue; Jing, Xiao Yan; He, Li Yi; Yuan, Yi

    2009-08-07

    This work presents electrochemical formation of Mg-Li-Ca alloys via codeposition of Mg, Li and Ca on a molybdenum electrode in KCl-LiCl-MgCl(2)-CaCl(2) melts at 943 K. Cyclic voltammograms (CVs) showed that the underpotential deposition (UPD) of calcium on pre-deposited magnesium leads to the formation of a liquid Mg-Ca alloy, and the succeeding underpotential deposition of lithium on pre-deposited Mg-Ca alloy leads to the formation of a liquid Mg-Li-Ca solution. Chronopotentiometric measurements indicated that the codepositon of Mg, Li and Ca occurs at current densities more negative than -0.31 A cm(-2) in LiCl-KCl-MgCl(2) (5 wt%) melts containing 1 wt% CaCl(2). Chronoamperograms demonstrated that the onset potential for the codeposition of Mg, Li and Ca is -2.200 V, and the codeposition of Mg, Li and Ca is formed when the applied potentials are more negative than -2.200 V. X-Ray diffraction (XRD) indicated that Mg-Li-Ca alloys with different phases were formed via galvanostatic electrolysis. The microstructures of typical alpha and beta phases of Mg-Li-Ca alloys were characterized by optical microscope (OM) and scanning electron microscopy (SEM). The analysis of energy dispersive spectrometry (EDS) showed that the element Ca mainly distributes along grain boundary in Mg-Li-Ca alloys. The results of inductively coupled plasma analysis determined that the chemical compositions of Mg-Li-Ca alloys correspond with the phase structures of XRD patterns, and the lithium and calcium contents of Mg-Li-Ca alloys depend on the concentrations of MgCl(2) and CaCl(2).

  3. CA19-9antigenlevelscandistinguishbetween benignandmalignantpancreaticobiliarydisease

    Institute of Scientific and Technical Information of China (English)

    Gareth Morris-Stiff; Mary Teli; Nicky Jardine; Malcolm CA Puntis

    2009-01-01

    BACKGROUND: CA19-9 is a carbohydrate tumor-associated antigen which is frequently upregulated in pancreatobiliary neoplasia. However, it may also be elevated in patients with jaundice in the absence of a tumor due to biliary obstruction, and in other non-hepato-pancreatico-biliary conditions. This study aimed to evaluate whether CA19-9 levels could accurately differentiate between benign and malignant pancreatobiliary disease. METHODS: All patients referred to a single surgeon for investigation of pancreaticobiliary disease in 2003 in whom a ifrm diagnosis had been established were included. For malignant disease, a histological diagnosis was required but for benign disease a ifrm radiological diagnosis was deemed adequate. The patients were divided into 4 categories:pancreatic adenocarcinoma (PCa); cholangiocarcinoma (CCa); chronic pancreatitis (CP) and biliary calculous disease (Calc). Bilirubin and alkaline phosphatase levels corresponding to the point of assessment of CA19-9 were also noted. RESULTS:  Final diagnoses were made of pancreatic adenocarcinoma (PCa, n=73), cholangiocarcinoma (CCa, n=19), ampullary carcinoma (Amp, n=7), neuroendocrine carcinoma (Neu, n=4), duodenal carcinoma (Duo, n=3), chronic pancreatitis (CP, n=115), and biliary calculous disease (Calc, n=27). Median CA19-9 levels (U/ml) were:PCa, 653;CCa, 408;Duo, 403;Calc, 27;CP, 19;Neu, 10.5;Amp, 8 (reference range: 0-37). The CA19-9 levels were signiifcantly greater for malignant than for benign disease, could differentiate PCa from CCa/Duo, and were signiifcantly higher in unresectable than in resectable PCa. The sensitivity, speciifcity, positive predictive value (PPV) and negative predictive value (NPV) for CA19-9 were 84.9%, 69.7%, 67.7%and 86.1%, respectively. A ROC analysis provided an area under the curve for CA19-9 of 0.871 (0.820-0.922), giving an optimal CA19-9 of 70.5 U/ml for differentiating benign from malignant pathology. Using this cut-off, the sensitivity was 82

  4. Hippocampal CA1 Ripples as Inhibitory Transients.

    Directory of Open Access Journals (Sweden)

    Paola Malerba

    2016-04-01

    Full Text Available Memories are stored and consolidated as a result of a dialogue between the hippocampus and cortex during sleep. Neurons active during behavior reactivate in both structures during sleep, in conjunction with characteristic brain oscillations that may form the neural substrate of memory consolidation. In the hippocampus, replay occurs within sharp wave-ripples: short bouts of high-frequency activity in area CA1 caused by excitatory activation from area CA3. In this work, we develop a computational model of ripple generation, motivated by in vivo rat data showing that ripples have a broad frequency distribution, exponential inter-arrival times and yet highly non-variable durations. Our study predicts that ripples are not persistent oscillations but result from a transient network behavior, induced by input from CA3, in which the high frequency synchronous firing of perisomatic interneurons does not depend on the time scale of synaptic inhibition. We found that noise-induced loss of synchrony among CA1 interneurons dynamically constrains individual ripple duration. Our study proposes a novel mechanism of hippocampal ripple generation consistent with a broad range of experimental data, and highlights the role of noise in regulating the duration of input-driven oscillatory spiking in an inhibitory network.

  5. Hippocampal CA1 Ripples as Inhibitory Transients.

    Science.gov (United States)

    Malerba, Paola; Krishnan, Giri P; Fellous, Jean-Marc; Bazhenov, Maxim

    2016-04-01

    Memories are stored and consolidated as a result of a dialogue between the hippocampus and cortex during sleep. Neurons active during behavior reactivate in both structures during sleep, in conjunction with characteristic brain oscillations that may form the neural substrate of memory consolidation. In the hippocampus, replay occurs within sharp wave-ripples: short bouts of high-frequency activity in area CA1 caused by excitatory activation from area CA3. In this work, we develop a computational model of ripple generation, motivated by in vivo rat data showing that ripples have a broad frequency distribution, exponential inter-arrival times and yet highly non-variable durations. Our study predicts that ripples are not persistent oscillations but result from a transient network behavior, induced by input from CA3, in which the high frequency synchronous firing of perisomatic interneurons does not depend on the time scale of synaptic inhibition. We found that noise-induced loss of synchrony among CA1 interneurons dynamically constrains individual ripple duration. Our study proposes a novel mechanism of hippocampal ripple generation consistent with a broad range of experimental data, and highlights the role of noise in regulating the duration of input-driven oscillatory spiking in an inhibitory network.

  6. 76 FR 20433 - California Disaster #CA-00169

    Science.gov (United States)

    2011-04-12

    ... ADMINISTRATION California Disaster CA-00169 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of California dated 04/05/2011. Incident: Center Fire. Incident Period: 03/18/2011 through 03/20/2011. Effective Date:...

  7. 78 FR 55771 - California Disaster #CA-00207

    Science.gov (United States)

    2013-09-11

    ... ADMINISTRATION California Disaster CA-00207 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of CALIFORNIA dated 08/26/2013. Incident: Silver Fire. Incident Period: 08/07/2013 through 08/14/2013. Effective Date:...

  8. 76 FR 62132 - California Disaster #CA-00176

    Science.gov (United States)

    2011-10-06

    ... ADMINISTRATION California Disaster CA-00176 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of California dated 09/29/2011. Incident: Canyon Fire. Incident Period: 09/04/2011 through 09/11/2011. Effective Date:...

  9. 78 FR 60366 - California Disaster #CA-00212

    Science.gov (United States)

    2013-10-01

    ... ADMINISTRATION California Disaster CA-00212 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of California dated 09/24/2013. Incident: Clover Fire Incident Period: 09/09/2013 through 09/15/2013. Effective Date:...

  10. 77 FR 1971 - California Disaster #CA-00183

    Science.gov (United States)

    2012-01-12

    ... ADMINISTRATION California Disaster CA-00183 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of California dated 01/05/2012. Incident: 1502 Golden Gate Fire. Incident Period: 12/22/2011. Effective Date:...

  11. 78 FR 39821 - California Disaster #CA-00202

    Science.gov (United States)

    2013-07-02

    ... ADMINISTRATION California Disaster CA-00202 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of California dated 06/25/2013. Incident: Powerhouse Fire. Incident Period: 05/30/2013 through 06/11/2013. Effective Date:...

  12. 78 FR 77195 - California Disaster #CA-00214

    Science.gov (United States)

    2013-12-20

    ... ADMINISTRATION California Disaster CA-00214 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for the State of California (FEMA- 4158-DR), dated 12/13/2013. Incident: Rim Fire. Incident Period:...

  13. 76 FR 16029 - CALIFORNIA Disaster #CA-00165

    Science.gov (United States)

    2011-03-22

    ... ADMINISTRATION CALIFORNIA Disaster CA-00165 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of CALIFORNIA dated 03/16/2011. Incident: Garden Breeze Apartment Complex Fire. Incident Period: 02/20/2011. DATES:...

  14. 76 FR 79751 - California Disaster #CA-00181

    Science.gov (United States)

    2011-12-22

    ... ADMINISTRATION California Disaster CA-00181 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of California dated 12/14/2011. Incident: Sequoia Apartment Complex Fire. Incident Period: 11/18/2011. Effective Date:...

  15. Numerical model of Ca(OH)

    NARCIS (Netherlands)

    Koster, T.; Peelen, W.; Larbi, J.; Rooij, M. de; Polder, R.

    2010-01-01

    A mathematical model is being developed to describe a repair method in concrete, called cathodic protection (CP). The model is in principle also useful to describe electrodeposition in concrete, e.g. the process of re-precipitation of Ca(OH)2 invoked by an electrical current. In CP, the c

  16. 75 FR 8414 - California Disaster # CA-00150

    Science.gov (United States)

    2010-02-24

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION California Disaster CA-00150 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of California dated...

  17. 76 FR 7622 - California Disaster #CA-00162

    Science.gov (United States)

    2011-02-10

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION California Disaster CA-00162 AGENCY: U.S. Small Business Administration. ] ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of California dated...

  18. 77 FR 61815 - California Disaster #CA-00190

    Science.gov (United States)

    2012-10-11

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION California Disaster CA-00190 AGENCY: U.S. Small Business Administration. ACTION: Amendment 1. SUMMARY: This is an amendment of the Administrative declaration of a disaster for the State of...

  19. 76 FR 38263 - California Disaster #CA-00172

    Science.gov (United States)

    2011-06-29

    ... From the Federal Register Online via the Government Publishing Office Small Business Administration California Disaster CA-00172 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for...

  20. 75 FR 17792 - California Disaster # CA-00150

    Science.gov (United States)

    2010-04-07

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION California Disaster CA-00150 AGENCY: U.S. Small Business Administration. ACTION: Amendment 1. SUMMARY: This is an amendment of the Administrative declaration of disaster for the State of...

  1. 76 FR 5856 - California Disaster #CA-00164

    Science.gov (United States)

    2011-02-02

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION California Disaster CA-00164 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for...

  2. 75 FR 13144 - California Disaster #CA-00151

    Science.gov (United States)

    2010-03-18

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION California Disaster CA-00151 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for...

  3. 76 FR 11307 - California Disaster #CA-00162

    Science.gov (United States)

    2011-03-01

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION California Disaster CA-00162 AGENCY: U.S. Small Business Administration. ACTION: Amendment 1. SUMMARY: This is an amendment of the Administrative declaration of a disaster for the State of...

  4. 75 FR 68848 - California Disaster #CA-00160

    Science.gov (United States)

    2010-11-09

    ... [Federal Register Volume 75, Number 216 (Tuesday, November 9, 2010)] [Notices] [Pages 68848-68849] [FR Doc No: 2010-28201] SMALL BUSINESS ADMINISTRATION [Disaster Declaration 12370 and 12371] California Disaster CA-00160 AGENCY: U.S. Small Business Administration. [[Page 68849

  5. 76 FR 18614 - California Disaster #CA-00167

    Science.gov (United States)

    2011-04-04

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION California Disaster CA-00167 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of California dated...

  6. 76 FR 80446 - California Disaster #CA-00182

    Science.gov (United States)

    2011-12-23

    ... [Federal Register Volume 76, Number 247 (Friday, December 23, 2011)] [Notices] [Pages 80446-80447] [FR Doc No: 2011-32952] SMALL BUSINESS ADMINISTRATION [Disaster Declaration 12967 and 12968] California Disaster CA-00182 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is...

  7. 76 FR 24555 - California Disaster #CA-00171

    Science.gov (United States)

    2011-05-02

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION California Disaster CA-00171 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of CALIFORNIA dated...

  8. 77 FR 58901 - California Disaster #CA-00190

    Science.gov (United States)

    2012-09-24

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION California Disaster CA-00190 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of California dated...

  9. 75 FR 27846 - California Disaster # CA-00155

    Science.gov (United States)

    2010-05-18

    ... [Federal Register Volume 75, Number 95 (Tuesday, May 18, 2010)] [Notices] [Page 27846] [FR Doc No: 2010-11746] SMALL BUSINESS ADMINISTRATION [Disaster Declaration 12166 and 12167] California Disaster CA-00155 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of...

  10. 75 FR 69733 - California Disaster #CA-00161

    Science.gov (United States)

    2010-11-15

    ... [Federal Register Volume 75, Number 219 (Monday, November 15, 2010)] [Notices] [Page 69733] [FR Doc No: 2010-28587] SMALL BUSINESS ADMINISTRATION [Disaster Declaration 12373 and 12374] California Disaster CA-00161 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice...

  11. 75 FR 22872 - California Disaster # CA-00154

    Science.gov (United States)

    2010-04-30

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION California Disaster CA-00154 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of California dated...

  12. literacy.ca EXPRESS. April 2010

    Science.gov (United States)

    Movement for Canadian Literacy, 2010

    2010-01-01

    This issue of "literacy.ca EXPRESS" focuses on poverty. The articles included in this issue are: (1) Poverty Overview; (2) Tony's Story; (3) LAN (Learner Advisory Network) Member's Story (Dianne Smith); (4) Linking Adult Literacy to Poverty Reduction; (5) MCL (Movement for Canadian Literacy) Update; (6) Highlights from the LAN; (7) Good…

  13. Ca(2+)-activated chloride channel activity during Ca(2+) alternans in ventricular myocytes.

    Science.gov (United States)

    Kanaporis, Giedrius; Blatter, Lothar A

    2016-11-01

    Cardiac alternans, defined beat-to-beat alternations in contraction, action potential (AP) morphology or cytosolic Ca transient (CaT) amplitude, is a high risk indicator for cardiac arrhythmias. We investigated mechanisms of cardiac alternans in single rabbit ventricular myocytes. CaTs were monitored simultaneously with membrane currents or APs recorded with the patch clamp technique. A strong correlation between beat-to-beat alternations of AP morphology and CaT alternans was observed. During CaT alternans application of voltage clamp protocols in form of pre-recorded APs revealed a prominent Ca(2+)-dependent membrane current consisting of a large outward component coinciding with AP phases 1 and 2, followed by an inward current during AP repolarization. Approximately 85% of the initial outward current was blocked by Cl(-) channel blocker DIDS or lowering external Cl(-) concentration identifying it as a Ca(2+)-activated Cl(-) current (ICaCC). The data suggest that ICaCC plays a critical role in shaping beat-to-beat alternations in AP morphology during alternans.

  14. DA-6034 Induces [Ca(2+)]i Increase in Epithelial Cells.

    Science.gov (United States)

    Yang, Yu-Mi; Park, Soonhong; Ji, Hyewon; Kim, Tae-Im; Kim, Eung Kweon; Kang, Kyung Koo; Shin, Dong Min

    2014-04-01

    DA-6034, a eupatilin derivative of flavonoid, has shown potent effects on the protection of gastric mucosa and induced the increases in fluid and glycoprotein secretion in human and rat corneal and conjunctival cells, suggesting that it might be considered as a drug for the treatment of dry eye. However, whether DA-6034 induces Ca(2+) signaling and its underlying mechanism in epithelial cells are not known. In the present study, we investigated the mechanism for actions of DA-6034 in Ca(2+) signaling pathways of the epithelial cells (conjunctival and corneal cells) from human donor eyes and mouse salivary gland epithelial cells. DA-6034 activated Ca(2+)-activated Cl(-) channels (CaCCs) and increased intracellular calcium concentrations ([Ca(2+)]i) in primary cultured human conjunctival cells. DA-6034 also increased [Ca(2+)]i in mouse salivary gland cells and human corneal epithelial cells. [Ca(2+)]i increase of DA-6034 was dependent on the Ca(2+) entry from extracellular and Ca(2+) release from internal Ca(2+) stores. Interestingly, these effects of DA-6034 were related to ryanodine receptors (RyRs) but not phospholipase C/inositol 1,4,5-triphosphate (IP3) pathway and lysosomal Ca(2+) stores. These results suggest that DA-6034 induces Ca(2+) signaling via extracellular Ca(2+) entry and RyRs-sensitive Ca(2+) release from internal Ca(2+) stores in epithelial cells.

  15. Cenozoic seawater Sr/Ca evolution

    Science.gov (United States)

    Sosdian, Sindia M.; Lear, Caroline H.; Tao, Kai; Grossman, Ethan L.; O'Dea, Aaron; Rosenthal, Yair

    2012-10-01

    Records of seawater chemistry help constrain temporal variations in geochemical processes that impact the global carbon cycle and climate through Earth's history. Here we reconstruct Cenozoic seawater Sr/Ca (Sr/Casw) using fossil Conus and turritellid gastropod Sr/Ca. Combined with an oxygen isotope paleotemperature record from the same samples, the gastropod record suggests that Sr/Caswwas slightly higher in the Eocene (˜11.4 ± 3 mmol/mol) than today (˜8.54 mmol/mol) and remained relatively stable from the mid- to late Cenozoic. We compare our gastropod Cenozoic Sr/Casw record with a published turritellid gastropod Sr/Casw record and other published biogenic (benthic foraminifera, fossil fish teeth) and inorganic precipitate (calcite veins) Sr/Caswrecords. Once the uncertainties with our gastropod-derived Sr/Casw are taken into account the Sr/Casw record agrees reasonably well with biogenic Sr/Caswrecords. Assuming a seawater [Ca] history derived from marine evaporite inclusions, all biogenic-based Sr/Casw reconstructions imply decreasing seawater [Sr] through the Cenozoic, whereas the calcite vein Sr/Casw reconstruction implies increasing [Sr] through the Cenozoic. We apply a simple geochemical model to examine the implications of divergence among these seawater [Sr] reconstructions and suggest that the interpretation and uncertainties associated with the gastropod and calcite vein proxies need to be revisited. Used in conjunction with records of carbonate depositional fluxes, our favored seawater Sr/Ca scenarios point to a significant increase in the proportion of aragonite versus calcite deposition in shelf sediments from the Middle Miocene, coincident with the proliferation of coral reefs. We propose that this occurred at least 10 million years after the seawater Mg/Ca threshold was passed, and was instead aided by declining levels of atmospheric carbon dioxide.

  16. Imaging of Ca2+ transients induced in Paramecium cells by a polyamine secretagogue.

    Science.gov (United States)

    Klauke, N; Plattner, H

    1997-04-01

    In Paramecium tetraurelia cells analysis of transient changes in Ca2+ concentration, [Ca2+]i, during aminoethyldextran (AED) stimulated synchronous ( or =20 seconds. Because of cell dislocation during vigorous trichocyst exocytosis, 7S cells could be reasonably analysed only by CLSM after Fluo-3 injection. In 7S cells cortical [Ca2+]i transients are strictly parallelled by trichocyst exocytosis, i.e. in the subsecond time range and precisely at the site of AED application. Injection of Ca2+ is a much less efficient trigger for exocytosis. Ca2+-buffer injections suggest a requirement of [Ca2+]i >1 to 10 microM for exocytosis to occur in response to AED. In conclusion, our data indicate: (i) correlation of cortical [Ca2+]i transients with exocytosis, as well as (ii) occurrence of a similar signal transduction mechanism in mutant cells where target structures may be defective or absent.

  17. Serum concentrations of the biomarkers CA125, CA15-3, CA72-4, tPSA and PAPP-A in natural and stimulated ovarian cycles

    Directory of Open Access Journals (Sweden)

    Melissa Stemp

    2014-06-01

    Conclusion: Ovarian stimulation reduced serum PAPP‐A levels, CA125 and CA15‐3 levels were generally unaffected by ovarian stimulation but displayed cyclical changes throughout both natural and stimulated cycles, whilst tPSA and CA72-4 were not affected by the stage of the cycle or ovarian stimulation.

  18. Feedforward inhibition underlies the propagation of cholinergically induced gamma oscillations from hippocampal CA3 to CA1.

    Science.gov (United States)

    Zemankovics, Rita; Veres, Judit M; Oren, Iris; Hájos, Norbert

    2013-07-24

    Gamma frequency (30-80 Hz) oscillations are implicated in memory processing. Such rhythmic activity can be generated intrinsically in the CA3 region of the hippocampus from where it can propagate to the CA1 area. To uncover the synaptic mechanisms underlying the intrahippocampal spread of gamma oscillations, we recorded local field potentials, as well as action potentials and synaptic currents in anatomically identified CA1 and CA3 neurons during carbachol-induced gamma oscillations in mouse hippocampal slices. The firing of the vast majority of CA1 neurons and all CA3 neurons was phase-coupled to the oscillations recorded in the stratum pyramidale of the CA1 region. The predominant synaptic input to CA1 interneurons was excitatory, and their discharge followed the firing of CA3 pyramidal cells at a latency indicative of monosynaptic connections. Correlation analysis of the input-output characteristics of the neurons and local pharmacological block of inhibition both agree with a model in which glutamatergic CA3 input controls the firing of CA1 interneurons, with local pyramidal cell activity having a minimal role. The firing of phase-coupled CA1 pyramidal cells was controlled principally by their inhibitory inputs, which dominated over excitation. Our results indicate that the synchronous firing of CA3 pyramidal cells rhythmically recruits CA1 interneurons and that this feedforward inhibition generates the oscillatory activity in CA1. These findings identify distinct synaptic mechanisms underlying the generation of gamma frequency oscillations in neighboring hippocampal subregions.

  19. Ca2+ signals regulate mitochondrial metabolism by stimulating CREB-mediated expression of the mitochondrial Ca2+ uniporter gene MCU.

    Science.gov (United States)

    Shanmughapriya, Santhanam; Rajan, Sudarsan; Hoffman, Nicholas E; Zhang, Xueqian; Guo, Shuchi; Kolesar, Jill E; Hines, Kevin J; Ragheb, Jonathan; Jog, Neelakshi R; Caricchio, Roberto; Baba, Yoshihiro; Zhou, Yandong; Kaufman, Brett A; Cheung, Joseph Y; Kurosaki, Tomohiro; Gill, Donald L; Madesh, Muniswamy

    2015-03-03

    Cytosolic Ca2+ signals, generated through the coordinated translocation of Ca2+ across the plasma membrane (PM) and endoplasmic reticulum (ER) membrane, mediate diverse cellular responses. Mitochondrial Ca2+ is important for mitochondrial function, and when cytosolic Ca2+ concentration becomes too high, mitochondria function as cellular Ca2+ sinks. By measuring mitochondrial Ca2+ currents, we found that mitochondrial Ca2+ uptake was reduced in chicken DT40 B lymphocytes lacking either the ER-localized inositol trisphosphate receptor (IP3R), which releases Ca2+ from the ER, or Orai1 or STIM1, components of the PM-localized Ca2+ -permeable channel complex that mediates store-operated calcium entry (SOCE) in response to depletion of ER Ca2+ stores. The abundance of MCU, the pore-forming subunit of the mitochondrial Ca2+ uniporter, was reduced in cells deficient in IP3R, STIM1, or Orai1. Chromatin immunoprecipitation and promoter reporter analyses revealed that the Ca2+ -regulated transcription factor CREB (cyclic adenosine monophosphate response element-binding protein) directly bound the MCU promoter and stimulated expression. Lymphocytes deficient in IP3R, STIM1, or Orai1 exhibited altered mitochondrial metabolism, indicating that Ca2+ released from the ER and SOCE-mediated signals modulates mitochondrial function. Thus, our results showed that a transcriptional regulatory circuit involving Ca2+ -dependent activation of CREB controls the Ca2+ uptake capability of mitochondria and hence regulates mitochondrial metabolism.

  20. Structural Changes in the Mn4Ca Cluster and the Mechanism of Photosynthetic Water Splitting

    Energy Technology Data Exchange (ETDEWEB)

    Pushkar, Y.; Yano, J.; Sauer, K.; Boussac, A.; Yachandra, V.K.

    2007-10-25

    Photosynthetic water oxidation, where water is oxidized to dioxygen, is a fundamental chemical reaction that sustains the biosphere. This reaction is catalyzed by a Mn4Ca complex in the photosystem II (PS II) oxygen-evolving complex (OEC): a multiproteinassembly embedded in the thylakoid membranes of green plants, cyanobacteria, and algae. The mechanism of photosynthetic water oxidation by the Mn4Ca cluster in photosystem II is the subject of much debate, although lacking structural characterization of the catalytic intermediates. Biosynthetically exchanged Ca/Sr-PS II preparations and x-ray spectroscopy, including extended x-ray absorption fine structure (EXAFS), allowed us to monitor Mn-Mn and Ca(Sr)-Mn distances in the four intermediate S states, S0 through S3, of the catalytic cycle that couples the one-electron photochemistry occurring at the PS II reaction center with the four-electron water-oxidation chemistry taking place at the Mn4Ca(Sr) cluster. We have detected significant changes in the structure of the complex, especially in the Mn-Mn and Ca(Sr)-Mn distances, on the S2-to-S3 and S3-to-S0 transitions. These results implicate the involvement of at least one common bridging oxygen atom between the Mn-Mn and Mn-Ca(Sr) atoms in the O-O bond formation. Because PS II cannot advance beyond the S2 state in preparations that lack Ca(Sr), these results show that Ca(Sr) is one of the critical components in the mechanism of the enzyme. The results also show that Ca is not just a spectator atom involved in providing a structural framework, but is actively involved in the mechanism of water oxidation and represents a rare example of a catalytically active Ca cofactor.

  1. The alterations of Ca2+/calmodulin/CaMKII/CaV1.2 signaling in experimental models of Alzheimer's disease and vascular dementia.

    Science.gov (United States)

    Min, Dongyu; Guo, Feng; Zhu, Shu; Xu, Xiaoxue; Mao, Xiaoyuan; Cao, Yonggang; Lv, Xintong; Gao, Qinghua; Wang, Lei; Chen, Tianbao; Shaw, Chris; Hao, Liying; Cai, Jiqun

    2013-03-22

    The two critical forms of dementia are Alzheimer's disease (AD) and vascular dementia (VD). The alterations of Ca(2+)/calmodulin/CaMKII/CaV1.2 signaling in AD and VD have not been well elucidated. Here we have demonstrated changes in the levels of CaV1.2, calmodulin, p-CaMKII, p-CREB and BDNF proteins by Western blot analysis and the co-localization of p-CaMKII/CaV1.2 by double-labeling immunofluorescence in the hippocampus of APP/PS1 mice and VD gerbils. Additionally, expression of these proteins and intracellular calcium levels were examined in cultured neurons treated with Aβ1-42. The expression of CaV1.2 protein was increased in VD gerbils and in cultured neurons but decreased in APP/PS1 mice; the expression of calmodulin protein was increased in APP/PS1 mice and VD gerbils; levels of p-CaMKII, p-CREB and BDNF proteins were decreased in AD and VD models. The number of neurons in which p-CaMKII and CaV1.2 were co-localized, was decreased in the CA1 and CA3 regions in two models. Intracellular calcium was increased in the cultured neurons treated with Aβ1-42. Collectively, our results suggest that the alterations in CaV1.2, calmodulin, p-CaMKII, p-CREB and BDNF can be reflective of an involvement in the impairment in memory and cognition in AD and VD models.

  2. Ca2+ dialogue between acidic vesicles and ER.

    Science.gov (United States)

    Morgan, Anthony J

    2016-04-15

    Extracellular stimuli evoke the synthesis of intracellular second messengers, several of which couple to the release of Ca(2+)from Ca(2+)-storing organelles via activation of cognate organellar Ca(2+)-channel complexes. The archetype is the inositol 1,4,5-trisphosphate (IP3) and IP3receptor (IP3R) on the endoplasmic reticulum (ER). A less understood, parallel Ca(2+)signalling cascade is that involving the messenger nicotinic acid adenine dinucleotide phosphate (NAADP) that couples to Ca(2+)release from acidic Ca(2+)stores [e.g. endo-lysosomes, secretory vesicles, lysosome-related organelles (LROs)]. NAADP-induced Ca(2+)release absolutely requires organellar TPCs (two-pore channels). This review discusses how ER and acidic Ca(2+)stores physically and functionally interact to generate and shape global and local Ca(2+)signals, with particular emphasis on the two-way dialogue between these two organelles.

  3. Ca2+-binding protein-1 facilitates and forms a postsynaptic complex with Cav1.2 (L-type) Ca2+ channels.

    Science.gov (United States)

    Zhou, Hong; Kim, Seong-Ah; Kirk, Elizabeth A; Tippens, Alyssa L; Sun, Hong; Haeseleer, Françoise; Lee, Amy

    2004-05-12

    Ca2+-binding protein-1 (CaBP1) is a Ca2+-binding protein that is closely related to calmodulin (CaM) and localized in somatodendritic regions of principal neurons throughout the brain, but how CaBP1 participates in postsynaptic Ca2+ signaling is not known. Here, we describe a novel role for CaBP1 in the regulation of Ca2+ influx through Ca(v)1.2 (L-type) Ca2+ channels. CaBP1 interacts directly with the alpha1 subunit of Ca(v)1.2 at sites that also bind CaM. CaBP1 binding to one of these sites, the IQ domain, is Ca2+ dependent and competitive with CaM binding. The physiological significance of this interaction is supported by the association of Ca(v)1.2 and CaBP1 in postsynaptic density fractions purified from rat brain. Moreover, in double-label immunofluorescence experiments, CaBP1 and Ca(v)1.2 colocalize in numerous cell bodies and dendrites of neurons, particularly in pyramidal cells in the CA3 region of the hippocampus and in the dorsal cortex. In electrophysiological recordings of cells transfected with Ca(v)1.2, CaBP1 greatly prolonged Ca2+ currents, prevented Ca2+-dependent inactivation, and caused Ca2+-dependent facilitation of currents evoked by step depolarizations and repetitive stimuli. These effects contrast with those of CaM, which promoted strong Ca2+-dependent inactivation of Ca(v)1.2 with these same voltage protocols. Our findings reveal how Ca2+-binding proteins, such as CaM and CaBP1, differentially adjust Ca2+ influx through Ca(v)1.2 channels, which may specify diverse modes of Ca2+ signaling in neurons.

  4. Reduction of Ca2+-transporting systems in memory T cells.

    Science.gov (United States)

    Sigova, A A; Dedkova, E N; Zinchenko, V P; Litvinov, I S

    2000-01-01

    Antigen-specific B and T lymphocytes make up the material grounds of immune memory, their main functional distinction from the so-called "naive" cells is due to the rapid and enhanced response to the antigen-pathogen. An essential distinction between the memory and naive T cells is different sensitivity of these two subpopulations of T lymphocytes to Ca2+-ionophores. Comparative analysis of Ca2+ responses of the immune memory T lymphocytes and naive T cells of mouse CBA/J line to the addition of Ca2+-mobilizing agents concanavalin A, thapsigargin, and ionomycin was carried out. These compounds in concentrations increasing [Ca2+]i in naive cells had no effect on [Ca2+]i in memory cells. Thus, the Ca2+ entrance into memory cells was not activated by exhaustion of intracellular resources. Estimation of intracellular resources of Ca2+, mobilized by ionomycin and thapsigargin in Ca2+ free medium has shown the absence in memory T cells of the intracellular Ca2+ pool, which may be one of factors of their resistance to ionophores. Reduction of the system of Ca2+ influx into memory T cells was shown using the SH-reagent thimerosal. Memory T cells appear to be resistant to "Ca2+ -paradox." Their incubation with 0.5 mM EDTA in the presence or absence of Ca2+ -mobilizing compounds followed by addition of 2 mM CaCl2 did not result in induction of Ca2+ influx into these cells.

  5. Precise half-life measurements for $^{38}$Ca and $^{39}$Ca

    CERN Document Server

    Blank, B; Demonchy, C-E; Borge, M J G; Matea, I; Munoz, F; Huikari, J; Dominguez-Reyes, R; Plaisir, C; Sturm, S; Canchel, G; Delahaye, P; Audirac, L; Fraile, L M; Serani, L; Lunney, D; Pedroza, J-L; Bey, A; Souin, J; Hui, Tran Trong; Delalee, F; Tengblad, O; Wenander, F

    2010-01-01

    The half-lives of Ca-38 and Ca-39 have been measured at ISOLDE of CERN. The REXTRAP facility was used to prepare ultra-clean samples of radioactive nuclei for precision decay spectroscopy. Ca-38 is one of the T-z = -1, 0(+). 0(+) beta-emitting nuclides used to determine the vector coupling constant of the weak interaction and the V-ud quark-mixing matrix element. The result obtained, T-1/2 = 443.8(19) ms, is four times more precise than the average of previous measurements. For Ca-39, a half-life of T-1/2 = 860.7(10) ms is obtained, a result in agreement with the average value from the literature.

  6. Fabrication aspects of PLA-CaP/PLGA-CaP composites for orthopedic applications: a review.

    Science.gov (United States)

    Zhou, Huan; Lawrence, Joseph G; Bhaduri, Sarit B

    2012-07-01

    For several decades, composites made of polylactic acid-calcium phosphates (PLA-CaP) and polylactic acid-co-glycolic acid-calcium phosphates (PLGA-CaP) have seen widespread uses in orthopedic applications. This paper reviews the fabrication aspects of these composites, following the ubiquitous materials science approach by studying "processing-structure-property" correlations. Various fabrication processes such as microencapsulation, phase separation, electrospinning, supercritical gas foaming, etc., are reviewed, with specific examples of their applications in fabricating these composites. The effect of the incorporation of CaP materials on the mechanical and biological performance of PLA/PLGA is addressed. In addition, this paper describes the state of the art on challenges and innovations concerning CaP dispersion, incorporation of biomolecules/stem cells and long-term degradation of the composites.

  7. Prenatal morphine exposure reduces pyramidal neurons in CA1, CA2 and CA3 subfields of mice hippocampus

    Directory of Open Access Journals (Sweden)

    Soraya Ghafari

    2014-03-01

    Full Text Available Objective(s:This study was carried out to evaluate the effect of maternal morphine exposure during gestational and lactation period on pyramidal neurons of hippocampus in 18 and 32 day mice offspring. Materials and Methods: Thirty female mice were randomly allocated into cases and controls. In case group, animals received morphinesulfate 10 mg/kg.body weight intraperitoneally during 7 days before mating, gestational period (GD 0-21, 18 and 32 days after delivery in the experimental groups. The control animals received an equivalent volume of normal saline. Cerebrum of six offsprings in each group was removed and stained with cresyl violet and a monoclonal antibody NeuN for immunohistochemical detection of surviving pyramidal neurons. Quantitative computer-assisted morphometric study was done on hippocampus. Results: The number of pyramidal neurons in CA1, CA2 and CA3 in treated groups was significantly reduced in postnatal day 18 and 32 (P18, P32 compared to control groups (P

  8. RNAi knockdown of PIK3CA preferentially inhibits invasion of mutant PIK3CA cells

    Institute of Scientific and Technical Information of China (English)

    Xin-Ke Zhou; Sheng-Song Tang; Gao Yi; Min Hou; Jin-Hui Chen; Bo Yang; Ji-Fang Liu; Zhi-Min He

    2011-01-01

    AIM: To explore the effects of siRNA silencing of PIK3CA on proliferation, migration and invasion of gastric cancer cells and to investigate the underlying mechanisms.METHODS: The mutation of PIK3CA in exons 9 and 20 of gastric cancer cell lines HGC-27, SGC-7901, BGC-823, MGC-803 and MKN-45 was screened by poly-merase chain reaction (PCR) followed by sequencing. BGC-823 cells harboring no mutations in either of the exons, and HGC-27 cells containing PIK3CA mutations were employed in the current study. siRNA targeting PIK3CA was chemically synthesized and was transfect-ed into these two cell lines in vitro. mRNA and protein expression of PIK3CA were detected by real-time PCR and Western blotting, respectively. We also measured phosphorylation of a serine/threonine protein kinase (Akt) using Western blotting. The proliferation, migra-tion and invasion of these cells were examined sepa-rately by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltet-razolium bromide (MTT), wound healing and Transwell chambers assay.RESULTS: The siRNA directed against PIK3CA effec-tively led to inhibition of both endogenous mRNA and protein expression of PIK3CA, and thus significantly down-regulated phosphorylation of Akt (P < 0.05). Furthermore, simultaneous silencing of PIK3CA result-ed in an obvious reduction in tumor cell proliferation activity, migration and invasion potential (P < 0.01). Intriguing, mutant HGC-27 cells exhibited stronger invasion ability than that shown by wild-type BGC-823 cells. Knockdown of PIK3CA in mutant HGC-27 cells contributed to a reduction in cell invasion to a greater extent than in non-mutant BGC-823 cells.CONCLUSION: siRNA mediated targeting of PIK3CA may specifically knockdown the expression of PIK3CA in gastric cancer cells, providing a potential implication for therapy of gastric cancer.

  9. Glutamate receptor activation in cultured cerebellar granule cells increases cytosolic free Ca2+ by mobilization of cellular Ca2+ and activation of Ca2+ influx

    DEFF Research Database (Denmark)

    Bouchelouche, P; Belhage, B; Frandsen, A;

    1989-01-01

    The Ca2+ sensitive fluorescent probe, fura-2 has been used to monitor cytosolic free calcium levels in mature primary cultures of cerebellar granule cells during exposure to L-glutamate and other excitatory amino acids: quisqualate (QA) kainate (KA) and N-methyl-D-aspartate (NMDA). Glutamate...... at micromolar concentrations produced a prompt and dose-related increase in the intracellular concentration of free Ca2+, ([Ca2+]i), whereas QA, KA and NMDA had no effect. This increase was also seen in the absence of extracellular Ca2+, suggesting that L-glutamate promotes mobilization of Ca2+ from...

  10. Progressive alterations of hippocampal CA3-CA1 synapses in an animal model of depression.

    Science.gov (United States)

    Qiao, Hui; An, Shu-Cheng; Ren, Wei; Ma, Xin-Ming

    2014-12-15

    Major depressive disorder is the most prevalent psychiatric condition, but the cellular and molecular mechanisms underlying this disorder are largely unknown, although multiple hypotheses have been proposed. The aim of this study was to characterize the progressive alteration of neuronal plasticity in the male rat hippocampus during depression induced by chronic unpredictable mild stress (CUMS), an established animal model of depression. The data in the hippocampus were collected on days 7, 14 and 21 after the onset of three-week CUMS. When analyzed on day 21, three-week CUMS induced typically depressive-like behaviors, impaired LTP induction, and decreased basal synaptic transmission at hippocampal CA3-CA1 synapses recorded in vivo, which was accompanied by decreased density of dendritic spines in CA1 and CA3 pyramidal neurons. The levels of both Kalirin-7 and brain-derived neurotrophic factor (BDNF) in the hippocampus were decreased at the same time. On day 14 (middle phase), some depressive-like behaviors were observed, which was accompanied by depressed basal synaptic transmission and enhanced LTP induction at the CA3-CA1 synapses. However, BDNF expression was decreased without alteration of Kalirin7 expression in comparison with no-stress control. Depressed basal synaptic transmission occurred in the middle phase of CUMS may contribute to decreased expression of BDNF. On day 7, depressive-like behaviors were not observed, and LTP induction, spine density, Kalirin-7 and BDNF expression were not altered by CUMS in comparison with no-stress control. These results showed that the functional changes at CA3-CA1synapses occurred earlier than the structural alteration during three-week CUMS as a strategy of neural adaptation, and rats required three weeks to develop depressive-like behaviors during CUMS. Our results suggest an important role of Kalirin-7 in CUMS-mediated alterations in spine density, synaptic function and overall depressive-like behaviors on day 21.

  11. CaMKII-dependent responses to ischemia and reperfusion challenges in the heart

    Directory of Open Access Journals (Sweden)

    James eBell

    2014-05-01

    Full Text Available Ischemic heart disease is a leading cause of death, and there is considerable imperative to identify effective therapeutic interventions. Cardiomyocyte Ca2+ overload is a major cause of ischemia and reperfusion injury, initiating a cascade of events culminating in cardiomyocyte death, myocardial dysfunction and occurrence of lethal arrhythmias. Responsive to fluctuations in intracellular Ca2+, Ca2+/calmodulin-dependent protein kinase II (CaMKII has emerged as an enticing therapeutic target in the management of ischemic heart injury. CaMKII is activated early in ischemia and to a greater extent in the first few minutes of reperfusion, at a time when reperfusion arrhythmias are particularly prominent. CaMKII phosphorylates and upregulates many of the key proteins involved in intracellular Na+ and Ca2+ loading in ischemia and reperfusion. Experimentally, selective inhibition of CaMKII activity reduces cardiomyocyte death and arrhythmic incidence post-ischemia. New evidence is emerging that CaMKII actions in ischemia and reperfusion involve specific splice variant targeted actions, selective and localized post-translational modifications, and organelle-directed substrate interactions. A more complete mechanistic understanding of CaMKII mode of action in ischemia and reperfusion is required to optimize intervention opportunities. This review summarizes the current experimentally-derived understanding of CaMKII participation in mediating the pathophysiology of the heart in ischemia and in reperfusion, and highlights priority future research directions.

  12. Dynamic impact of temporal context of Ca²⁺ signals on inhibitory synaptic plasticity.

    Science.gov (United States)

    Kawaguchi, Shin-Ya; Nagasaki, Nobuhiro; Hirano, Tomoo

    2011-01-01

    Neuronal activity-dependent synaptic plasticity, a basis for learning and memory, is tightly correlated with the pattern of increase in intracellular Ca(2+) concentration ([Ca(2+)](i)). Here, using combined application of electrophysiological experiments and systems biological simulation, we show that such a correlation dynamically changes depending on the context of [Ca(2+)](i) increase. In a cerebellar Purkinje cell, long-term potentiation of inhibitory GABA(A) receptor responsiveness (called rebound potentiation; RP) was induced by [Ca(2+)](i) increase in a temporally integrative manner through sustained activation of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII). However, the RP establishment was canceled by coupling of two patterns of RP-inducing [Ca(2+)](i) increase depending on the temporal sequence. Negative feedback signaling by phospho-Thr305/306 CaMKII detected the [Ca(2+)](i) context, and assisted the feedforward inhibition of CaMKII through PDE1, resulting in the RP impairment. The [Ca(2+)](i) context-dependent dynamic regulation of synaptic plasticity might contribute to the temporal refinement of information flow in neuronal networks.

  13. SERCA mutant E309Q binds two Ca ions but adopts a catalytically incompetent conformation

    DEFF Research Database (Denmark)

    Clausen, Johannes D.; Bublitz, Maike; Arnou, Bertrand;

    2013-01-01

    The sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) couples ATP hydrolysis to transport of Ca2+. This directed energy transfer requires cross-talk between the two Ca2+ sites and the phosphorylation site over 50 Å distance. We have addressed the mechano-structural basis for this intramolecular...... signal by analysing the structure and the functional properties of SERCA mutant E309Q. Glu309 contributes to Ca2+ coordination at site II, and a consensus has been that E309Q only binds Ca2+ at site I. The crystal structure of E309Q in the presence of Ca2+ and an ATP analogue, however, reveals two...... occupied Ca2+ sites of a non-catalytic Ca2E1 state. Ca2+ is bound with micromolar affinity by both Ca2+ sites in E309Q, but without cooperativity. The Ca2+-bound mutant does phosphorylate from ATP, but at a very low maximal rate. Phosphorylation depends on the correct positioning of the A-domain, requiring...

  14. Convergence of entorhinal and CA3 inputs onto pyramidal neurons and interneurons in hippocampal area CA1--an anatomical study in the rat.

    Science.gov (United States)

    Kajiwara, Riichi; Wouterlood, Floris G; Sah, Anupam; Boekel, Amber J; Baks-te Bulte, Luciënne T G; Witter, Menno P

    2008-01-01

    The entorhinal cortex (EC) conveys information to hippocampal field CA1 either directly by way of projections from principal neurons in layer III, or indirectly by axons from layer II via the dentate gyrus, CA3, and Schaffer collaterals. These two pathways differentially influence activity in CA1, yet conclusive evidence is lacking whether and to what extent they converge onto single CA1 neurons. Presently we studied such convergence. Different neuroanatomical tracers injected into layer III of EC and into CA3, respectively, tagged simultaneously the direct entorhino-hippocampal fibers and the indirect innervation of CA1 neurons by Schaffer collaterals. In slices of fixed brains we intracellularly filled CA1 pyramidal cells and interneurons in stratum lacunosum-moleculare (LM) and stratum radiatum (SR). Sections of these slices were scanned in a confocal laser scanning microscope. 3D-reconstruction was used to determine whether boutons of the labeled input fibers were in contact with the intracellularly filled neurons. We analyzed 12 pyramidal neurons and 21 interneurons. Perforant path innervation to pyramidal neurons in our material was observed to be denser than that from CA3. All pyramidal neurons and 17 of the interneurons received contacts of both perforant pathway and Schaffer input on their dendrites and cell bodies. Four interneurons, which were completely embedded in LM, received only labeled perforant pathway input. Thus, we found convergence of both projection systems on single CA1 pyramidal and interneurons with dendrites that access the layers where perforant pathway fibers and Schaffer collaterals end.

  15. The Reliability of Highly Elevated CA 19-9 Levels

    Directory of Open Access Journals (Sweden)

    B. R. Osswald

    1993-01-01

    Full Text Available CA 19-9 is used as a tumour marker of the upper gastrointestinal tract. However, extremely elevated CA 19-9 levels are found also in patients with benign diseases. Cholestasis was present in 97.1 % of patients with high elevated CA 19-9, independent of their primary disease. 50% of patients with non-malignant diseases and increased CA 19-9 levels showed liver cirrhosis, cholecystitis, pancreatitis and/or hepatitis. In 8.8% no explanation was found for the extremely high CA 19-9 level. The results provide evidence of different factors influencing the CA 19-9 level.

  16. Endo-lysosomal TRP mucolipin-1 channels trigger global ER Ca2+ release and Ca2+ influx

    Science.gov (United States)

    Kilpatrick, Bethan S.; Yates, Elizabeth; Grimm, Christian; Schapira, Anthony H.

    2016-01-01

    ABSTRACT Transient receptor potential (TRP) mucolipins (TRPMLs), encoded by the MCOLN genes, are patho-physiologically relevant endo-lysosomal ion channels crucial for membrane trafficking. Several lines of evidence suggest that TRPMLs mediate localised Ca2+ release but their role in Ca2+ signalling is not clear. Here, we show that activation of endogenous and recombinant TRPMLs with synthetic agonists evoked global Ca2+ signals in human cells. These signals were blocked by a dominant-negative TRPML1 construct and a TRPML antagonist. We further show that, despite a predominant lysosomal localisation, TRPML1 supports both Ca2+ release and Ca2+ entry. Ca2+ release required lysosomal and ER Ca2+ stores suggesting that TRPMLs, like other endo-lysosomal Ca2+ channels, are capable of ‘chatter’ with ER Ca2+ channels. Our data identify new modalities for TRPML1 action. PMID:27577094

  17. Neuronal Ca(2+) dyshomeostasis in Huntington disease.

    Science.gov (United States)

    Giacomello, Marta; Oliveros, Juan C; Naranjo, Jose R; Carafoli, Ernesto

    2013-01-01

    The expansion of the N-terminal poly-glutamine tract of the huntingtin (Htt) protein is responsible for Huntington disease (HD). A large number of studies have explored the neuronal phenotype of HD, but the molecular aethiology of the disease is still very poorly understood. This has hampered the development of an appropriate therapeutical strategy to at least alleviate its symptoms. In this short review, we have focused our attention on the alteration of a specific cellular mechanism common to all HD models, either genetic or induced by treatment with 3-NPA, i.e. the cellular dyshomeostasis of Ca(2+). We have highlighted the direct and indirect (i.e. transcriptionally mediated) effects of mutated Htt on the maintenance of the intracellular Ca(2+) balance, the correct modulation of which is fundamental to cell survival and the disturbance of which plays a key role in the death of the cell.

  18. Conversation Analysis (CA in Primary School Classrooms

    Directory of Open Access Journals (Sweden)

    Alberto Fajardo

    2008-12-01

    Full Text Available Although CA deals with all kinds of talk produced in natural contexts, this study focuses its interest on the talk produced in some primary school classrooms. It attempts to develop the construct that CA should move significantly ahead to more practical grounds where its detailed and isolated description causes some effect in improving foreign language teaching, for example. It might be used, for instance, to promote professional development in Colombia. It plans to involve pre-service teachers initially and in-service ones later. The kind of interaction promoted by trainee teachers shows a very restricted possibility for young learners to use the language meaningfully in the classroom. Four stages are defined and suggested as a path to follow with pre-service teachers at Universidad Pedagógica y Tecnológica de Colombia –UPTC– in the Foreign Language Programme - FLP.

  19. Honeybee locomotion is impaired by Am-CaV3 low voltage-activated Ca(2+) channel antagonist.

    Science.gov (United States)

    Rousset, M; Collet, C; Cens, T; Bastin, F; Raymond, V; Massou, I; Menard, C; Thibaud, J-B; Charreton, M; Vignes, M; Chahine, M; Sandoz, J C; Charnet, P

    2017-02-01

    Voltage-gated Ca(2+) channels are key transducers of cellular excitability and participate in several crucial physiological responses. In vertebrates, 10 Ca(2+) channel genes, grouped in 3 families (CaV1, CaV2 and CaV3), have been described and characterized. Insects possess only one member of each family. These genes have been isolated in a limited number of species and very few have been characterized although, in addition to their crucial role, they may represent a collateral target for neurotoxic insecticides. We have isolated the 3 genes coding for the 3 Ca(2+) channels expressed in Apis mellifera. This work provides the first detailed characterization of the honeybee T-type CaV3 Ca(2+) channel and demonstrates the low toxicity of inhibiting this channel. Comparing Ca(2+) currents recorded in bee neurons and myocytes with Ca(2+) currents recorded in Xenopus oocytes expressing the honeybee CaV3 gene suggests native expression in bee muscle cells only. High-voltage activated Ca(2+) channels could be recorded in the somata of different cultured bee neurons. These functional data were confirmed by in situ hybridization, immunolocalization and in vivo analysis of the effects of a CaV3 inhibitor. The biophysical and pharmacological characterization and the tissue distribution of CaV3 suggest a role in honeybee muscle function.

  20. Honeybee locomotion is impaired by Am-CaV3 low voltage-activated Ca2+ channel antagonist

    Science.gov (United States)

    Rousset, M.; Collet, C.; Cens, T.; Bastin, F.; Raymond, V.; Massou, I.; Menard, C.; Thibaud, J.-B.; Charreton, M.; Vignes, M.; Chahine, M.; Sandoz, J. C.; Charnet, P.

    2017-01-01

    Voltage‐gated Ca2+ channels are key transducers of cellular excitability and participate in several crucial physiological responses. In vertebrates, 10 Ca2+ channel genes, grouped in 3 families (CaV1, CaV2 and CaV3), have been described and characterized. Insects possess only one member of each family. These genes have been isolated in a limited number of species and very few have been characterized although, in addition to their crucial role, they may represent a collateral target for neurotoxic insecticides. We have isolated the 3 genes coding for the 3 Ca2+ channels expressed in Apis mellifera. This work provides the first detailed characterization of the honeybee T-type CaV3 Ca2+ channel and demonstrates the low toxicity of inhibiting this channel. Comparing Ca2+ currents recorded in bee neurons and myocytes with Ca2+ currents recorded in Xenopus oocytes expressing the honeybee CaV3 gene suggests native expression in bee muscle cells only. High‐voltage activated Ca2+ channels could be recorded in the somata of different cultured bee neurons. These functional data were confirmed by in situ hybridization, immunolocalization and in vivo analysis of the effects of a CaV3 inhibitor. The biophysical and pharmacological characterization and the tissue distribution of CaV3 suggest a role in honeybee muscle function. PMID:28145504

  1. Positive magnetoresistance in Ca-doped cobaltites

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, S. M., E-mail: zhousm@ustc.edu.cn; Li, Y.; Guo, Y. Q.; Zhao, J. Y.; Shi, L., E-mail: shil@ustc.edu.cn [Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2014-12-08

    Transport properties of polycrystalline La{sub 1−x}Ca{sub x}CoO{sub 3} (0.10 ≤ x ≤ 0.25) are systemically studied in this work. Three types of magnetoresistance (MR) effects are found in the Ca-doped cobaltites. Two negative MRs appear around high-temperature ferromagnetic transition and at low temperatures, which correspond to the conventional MR due to the field-induced suppression of spin-disorder scattering and the intergranular giant-MR due to spin-dependent transport between the ferromagnetic clusters, respectively. More interestingly, another exotic positive MR emerges at intermediate temperature region, which had not been previously reported in Sr- and Ba-doped cobaltites. It is found that this positive MR is associated with an abnormally magnetic transition and increases with the increase of x. For x = 0.25, the MR at low temperatures is dominated by the positive one, which is isotropic and nearly linear with the magnetic field. The possible origin of the positive MR in the Ca-doped cobaltites is discussed.

  2. de caña CAMECO

    Directory of Open Access Journals (Sweden)

    Carlos Suárez Ponciano

    2006-01-01

    Full Text Available El aumento de la producción de caña en Cuba se ha vuelto más que un objetivo una necesidad, es por ello que se introducen nuevas máquinas que den respuesta a esta situación. Teniendo esto como premisa y considerando la importancia que el cultivo de la caña tiene para el país es que se ha escogido el Complejo Agroindustrial (CAI «Héctor Molina Riaño» por la influencia que tiene, en la provincia La Habana, en los resultados de este cultivo para analizar el producto de los medios que intervienen en la cosecha y transporte de la caña de azúcar, así como las condiciones de explotación en que se desarrollan, lo cual constituye el objetivo de este trabajo. Se desarrolló una base metodológica para el análisis de los resultados.

  3. Superconductivity in Ca-doped graphene laminates

    Science.gov (United States)

    Chapman, J.; Su, Y.; Howard, C. A.; Kundys, D.; Grigorenko, A. N.; Guinea, F.; Geim, A. K.; Grigorieva, I. V.; Nair, R. R.

    2016-03-01

    Despite graphene’s long list of exceptional electronic properties and many theoretical predictions regarding the possibility of superconductivity in graphene, its direct and unambiguous experimental observation has not been achieved. We searched for superconductivity in weakly interacting, metal decorated graphene crystals assembled into so-called graphene laminates, consisting of well separated and electronically decoupled graphene crystallites. We report robust superconductivity in all Ca-doped graphene laminates. They become superconducting at temperatures (Tc) between ≈4 and ≈6 K, with Tc’s strongly dependent on the confinement of the Ca layer and the induced charge carrier concentration in graphene. We find that Ca is the only dopant that induces superconductivity in graphene laminates above 1.8 K among several dopants used in our experiments, such as potassium, caesium and lithium. By revealing the tunability of the superconducting response through doping and confinement of the metal layer, our work shows that achieving superconductivity in free-standing, metal decorated monolayer graphene is conditional on an optimum confinement of the metal layer and sufficient doping, thereby bringing its experimental realization within grasp.

  4. Superconductivity in Ca-doped graphene laminates

    Science.gov (United States)

    Chapman, J.; Su, Y.; Howard, C. A.; Kundys, D.; Grigorenko, A. N.; Guinea, F.; Geim, A. K.; Grigorieva, I. V.; Nair, R. R.

    2016-01-01

    Despite graphene’s long list of exceptional electronic properties and many theoretical predictions regarding the possibility of superconductivity in graphene, its direct and unambiguous experimental observation has not been achieved. We searched for superconductivity in weakly interacting, metal decorated graphene crystals assembled into so-called graphene laminates, consisting of well separated and electronically decoupled graphene crystallites. We report robust superconductivity in all Ca-doped graphene laminates. They become superconducting at temperatures (Tc) between ≈4 and ≈6 K, with Tc’s strongly dependent on the confinement of the Ca layer and the induced charge carrier concentration in graphene. We find that Ca is the only dopant that induces superconductivity in graphene laminates above 1.8 K among several dopants used in our experiments, such as potassium, caesium and lithium. By revealing the tunability of the superconducting response through doping and confinement of the metal layer, our work shows that achieving superconductivity in free-standing, metal decorated monolayer graphene is conditional on an optimum confinement of the metal layer and sufficient doping, thereby bringing its experimental realization within grasp. PMID:26979564

  5. Superconductivity in Ca-doped graphene laminates.

    Science.gov (United States)

    Chapman, J; Su, Y; Howard, C A; Kundys, D; Grigorenko, A N; Guinea, F; Geim, A K; Grigorieva, I V; Nair, R R

    2016-03-16

    Despite graphene's long list of exceptional electronic properties and many theoretical predictions regarding the possibility of superconductivity in graphene, its direct and unambiguous experimental observation has not been achieved. We searched for superconductivity in weakly interacting, metal decorated graphene crystals assembled into so-called graphene laminates, consisting of well separated and electronically decoupled graphene crystallites. We report robust superconductivity in all Ca-doped graphene laminates. They become superconducting at temperatures (Tc) between ≈4 and ≈6 K, with Tc's strongly dependent on the confinement of the Ca layer and the induced charge carrier concentration in graphene. We find that Ca is the only dopant that induces superconductivity in graphene laminates above 1.8 K among several dopants used in our experiments, such as potassium, caesium and lithium. By revealing the tunability of the superconducting response through doping and confinement of the metal layer, our work shows that achieving superconductivity in free-standing, metal decorated monolayer graphene is conditional on an optimum confinement of the metal layer and sufficient doping, thereby bringing its experimental realization within grasp.

  6. Arabidopsis transcriptional response to extracellular Ca2þ depletion involves a transient rise in cytosolic Ca

    Institute of Scientific and Technical Information of China (English)

    Zhi Qi

    2015-01-01

    Ecological evidence indicates a worldwide trend of dramatical y decreased soil Ca2þ levels caused by increased acid deposition and massive timber harvesting. Little is known about the genetic and cel ular mechanism of plants’ responses to Ca2þ depletion. In this study, transcriptional profiling analysis helped identify multiple extracel ular Ca2þ ([Ca2þ]ext) depletion‐respon-sive genes in Arabidopsis thaliana L., many of which are involved in response to other environmental stresses. Interestingly, a group of genes encoding putative cytosolic Ca2þ ([Ca2þ]cyt) sensors were significantly upregulated, implying that [Ca2þ]cyt has a role in sensing [Ca2þ]ext depletion. Consistent with this observation, [Ca2þ]ext depletion stimulated a transient rise in [Ca2þ]cyt that was negatively influenced by [Kþ]ext, suggesting the involvement of a membrane potential‐sensitive component. The [Ca2þ]cyt response to [Ca2þ]ext depletion was significantly desensitized after the initial treatment, which is typical of a receptor‐mediated signaling event. The response was insensi-tive to an animal Ca2þ sensor antagonist, but was suppressed by neomycin, an inhibitor of phospholipase C. Gd3þ, an inhibitor of Ca2þ channels, suppressed the [Ca2þ]ext‐triggered rise in [Ca2þ]cyt and downstream changes in gene expression. Taken together, this study demonstrates that [Ca2þ]cyt plays an important role in the putative receptor‐mediated cel ular and transcriptional response to [Ca2þ]ext depletion of plant cel s.

  7. Apamin Boosting of Synaptic Potentials in CaV2.3 R-Type Ca2+ Channel Null Mice.

    Science.gov (United States)

    Wang, Kang; Kelley, Melissa H; Wu, Wendy W; Adelman, John P; Maylie, James

    2015-01-01

    SK2- and KV4.2-containing K+ channels modulate evoked synaptic potentials in CA1 pyramidal neurons. Each is coupled to a distinct Ca2+ source that provides Ca2+-dependent feedback regulation to limit AMPA receptor (AMPAR)- and NMDA receptor (NMDAR)-mediated postsynaptic depolarization. SK2-containing channels are activated by Ca2+ entry through NMDARs, whereas KV4.2-containing channel availability is increased by Ca2+ entry through SNX-482 (SNX) sensitive CaV2.3 R-type Ca2+ channels. Recent studies have challenged the functional coupling between NMDARs and SK2-containing channels, suggesting that synaptic SK2-containing channels are instead activated by Ca2+ entry through R-type Ca2+ channels. Furthermore, SNX has been implicated to have off target affects, which would challenge the proposed coupling between R-type Ca2+ channels and KV4.2-containing K+ channels. To reconcile these conflicting results, we evaluated the effect of SK channel blocker apamin and R-type Ca2+ channel blocker SNX on evoked excitatory postsynaptic potentials (EPSPs) in CA1 pyramidal neurons from CaV2.3 null mice. The results show that in the absence of CaV2.3 channels, apamin application still boosted EPSPs. The boosting effect of CaV2.3 channel blockers on EPSPs observed in neurons from wild type mice was not observed in neurons from CaV2.3 null mice. These data are consistent with a model in which SK2-containing channels are functionally coupled to NMDARs and KV4.2-containing channels to CaV2.3 channels to provide negative feedback regulation of EPSPs in the spines of CA1 pyramidal neurons.

  8. Differential Ca2+ influx, KCa channel activity, and Ca2+ clearance distinguish Th1 and Th2 lymphocytes.

    Science.gov (United States)

    Fanger, C M; Neben, A L; Cahalan, M D

    2000-02-01

    In Th1 and Th2 lymphocytes, activation begins with identical stimuli but results in the production of different cytokines. The expression of some cytokine genes is differentially induced according to the amplitude and pattern of Ca2+ signaling. Using fura- 2 Ca2+ imaging of murine Th1 and Th2 clones, we observed that the Ca2+ rise elicited following store depletion with thapsigargin is significantly lower in Th2 cells than in Th1 cells. Maximal Ca2+ influx rates and whole-cell Ca2+ currents showed that both Th1 and Th2 cells express indistinguishable Ca2+-release-activated Ca2+ channels. Therefore, we investigated other mechanisms controlling the concentration of intracellular Ca2+, including K+ channels and Ca2+ clearance from the cytosol. Whole-cell recording demonstrated that there is no distinction in the amplitudes of voltage-gated K+ currents in the two cell types. Ca2+-activated K+ (KCa) currents, however, were significantly smaller in Th2 cells than in Th1 cells. Pharmacological equalization of Ca2+-activated K+ currents in the two cell types reduced but did not completely eliminate the difference between Th1 and Th2 Ca2+ responses, suggesting divergence in an additional Ca2+ regulatory mechanism. Therefore, we analyzed Ca2+ clearance from the cytosol of both cell types and found that Th2 cells extrude Ca2+ more quickly than Th1 cells. The combination of a faster Ca2+ clearance mechanism and smaller Ca2+-activated K+ currents in Th2 cells accounts for the lower Ca2+ response of Th2 cells compared with Th1 cells.

  9. The investigation on sulfation of modified Ca-based sorbent

    Energy Technology Data Exchange (ETDEWEB)

    Hongwei Chen; Chunbo Wang; Yonghua Li; Zijie Wang [North China Electric Power University, Baoding (China). Department of Power Engineering

    2003-07-01

    The sulfation of a limestone modified by Na{sub 2}CO{sub 3} was investigated in this paper, which aimed to find the causes of its enhanced sulfation capacity. It was shown in the experiment that although the sulfur capture capability of M-CaO (the CaO calcined from modified limestone) is in excess of that of N-CaO (the CaO calcined from original sample), the specific surface area and porosity of the former are much less than that of the latter and also the average pore radius of the former become bigger. Based on the solid-state ion diffusion theory, a new mechanism to explain M-CaO sulfation is suggested. More lattice defects are formed in M-CaO, which reduce the resistance of ion diffusion in the CaSO{sub 4} product layer, and increase the Ca-conversion. To verify this, XRD was applied to measure the crystal structures of CaO samples. It was found M-CaO has bigger lattice distortion than N-CaO. It means that M-CaO has more lattice defects. In the sulfation the lattice defects in M-CaO will go into the CaSO{sub 4} product layer and it is that accelerates the ion diffusivity and leads to the higher Ca-conversion than that of N-CaO. By scanning the element distribution in reacted M-CaO using SEM, how the lattice defects formed in the product layers was verified.

  10. Is tissue CA125 expression in epithelial ovarian adenocarcinoma heterogenic?

    DEFF Research Database (Denmark)

    Sparholt, Morten H; Høgdall, Claus K; Nedergaard, Lotte

    2013-01-01

    To evaluate if heterogeneity of tissue cancer antigen 125 (CA125) expression is present in epithelial serous adenocarcinomas. Furthermore, to investigate whether there is a correlation between levels of CA125 tissue expression, serum level of CA125, stage, and grade. A total of 10 patients...... diagnosed with serous ovarian adenocarcinomas were included. Preoperative blood samples were collected to determine serum CA125 levels. Tumor tissue from primary surgery was collected and processed for immunohistochemical analyses. CA125 was expressed in varying degrees in tumor tissues from all patients....... Mean tissue CA125 expression for each patient ranged from 36% to 98%. Intrapatient variations in tissue expression ranged from 10% to 90% point. No significant correlations between levels of CA125 tissue expression, serum level of CA125, stage, and grade were found. We found that the tissue expression...

  11. A study of the ground states of CaC2H+2,CaC2D+2 and CaC2H+4

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The geometries, vibrational frequencies and bind energies are reported for the ground states of CaC2H+2, CaC2D+2 and CaC2H+4. CaC2H+2 and CaC2H+4 equilibrium geometries have C2v symmetry with the metal ion lying in the perpendicular bisector of the C-C bond. The ground state in both CaC2H+2 and CaC2H+4 molecules ia a 2A1 state and the binding in the ground state is mainly electrostatic. For both CaC2H+2 and CaC2H+4 the ligand is only slightly distorted from its free ligand structure, the C-C distance has hardly increased and there is only a very small bending of the H atom away from the Ca atom. This is consistent with the electrostatic nature of the bonding. Two different approaches-Hartree-Fock(HF) and density functional theory methods(DFT)-are used and basis sets here used is 6-311+G(3df,2p). The DFT results are in good agreement with experiments, namely, DFT methods provide the benefits that some more expensive ab initio methods can do, but at essentially HF cost. So it is important to include electron correlation for accurate results in this study.

  12. Measurement of mitochondrial Ca2+ transport mediated by three transport proteins: VDAC1, the Na+/Ca2+ exchanger, and the Ca2+ uniporter.

    Science.gov (United States)

    Ben-Hail, Danya; Palty, Raz; Shoshan-Barmatz, Varda

    2014-02-01

    Ca(2+) is a ubiquitous cellular signal, with changes in intracellular Ca(2+) concentration not only stimulating a number of intercellular events but also triggering cell death pathways, including apoptosis. Mitochondrial Ca(2+) uptake and release play pivotal roles in cellular physiology by regulating intracellular Ca(2+) signaling, energy metabolism and cell death. Ca(2+) transport across the inner and outer mitochondrial membranes is mediated by several proteins, including channels, antiporters, and a uniporter. In this article, we present the background to several methods now established for assaying mitochondrial Ca(2+) transport activity across both mitochondrial membranes. The first of these is Ca(2+) transport mediated by the outer mitochondrial protein, the voltage-dependent anion-selective channel protein 1 (VDAC1, also known as porin 1), both as a purified protein reconstituted into a planar lipid bilayer (PLB) or into liposomes and as a mitochondrial membrane-embedded protein. The second method involves isolated mitochondria for assaying the activity of an inner mitochondrial membrane transport protein, the mitochondrial Ca(2+) uniporter (MCU) that transports Ca(2+) and is powered by the steep mitochondrial membrane potential. In the event of Ca(2+) overload, this leads to opening of the mitochondrial permeability transition pore (MPTP) and cell death. The third method describes how Na(+)-dependent mitochondrial Ca(2+) efflux mediated by mitochondrial NCLX, a member of the Na(+)/Ca(2+) exchanger superfamily, can be assayed in digitonin-permeabilized HEK-293 cells. The Ca(2+)-transport assays can be performed under various conditions and in combination with inhibitors, allowing detailed characterization of the transport activity of interest.

  13. Serum concentrations of the biomarkers CA125, CA15-3, CA72-4, tPSA and PAPP-A in natural and stimulated ovarian cycles

    Institute of Scientific and Technical Information of China (English)

    Melissa Stemp; Peter Roberts; Allison McClements; Vincent Chapple; Jay Natalwala; Michael Black; Phillip Matson

    2014-01-01

    Objective:Biomarkers associated with cancer screening (CA125, CA15‐3, CA72‐4, total prostate specific antigen [tPSA]) and the monitoring of pregnancy (pregnancy associated plasma protein‐A [PAPP‐A]) were measured during natural and stimulated ovarian cycles in disease‐free non-pregnant women to determine if they could reflect normal events relating to ovulation and/or endometrial changes. Methods: A total of 73 blood samples (10 women) collected throughout the natural menstrual cycle, and 64 blood samples (11 women) taken during stimulated ovarian cycles, were analysed on the Roche Cobas e411 automated analyser. Results:Detectable levels of tPSA were measured in at least one point in the cycle in 6/10 of women in the natural cycle and 10/11 of women in stimulated cycles, and CA72-4 was detected in only 12/21 women tested. Concentrations of CA125, tPSA, CA15‐3 and CA72‐4 showed no significant difference between the natural and stimulated ovarian cycle groups. On average the mean PAPP‐A of the natural group was (2.41±0.58) mIU/L higher than the stimulated group (t=4.10, P< 0.001). CA125 and CA15‐3 results were both significantly influenced by the stage of the cycle (P<0.0001), whereas tPSA and PAPP‐A concentrations revealed no significant changes (P≥0.65). CA72‐4 was not affected by the stage of the cycle nor ovarian stimulation. Conclusion:Ovarian stimulation reduced serum PAPP‐A levels, CA125 and CA15‐3 levels were generally unaffected by ovarian stimulation but displayed cyclical changes throughout both natural and stimulated cycles, whilst tPSA and CA72-4 were not affected by the stage of the cycle or ovarian stimulation.

  14. Sr/Ca and Ba/Ca variations in environmental and biological sources: A survey of marine and terrestrial systems

    Science.gov (United States)

    Peek, Stephanie; Clementz, Mark T.

    2012-10-01

    The relative concentrations of strontium to calcium (Sr/Ca) and barium to calcium (Ba/Ca) in mammalian bioapatite are common biogeochemical indicators for trophic level and/or dietary preferences in terrestrial foodwebs; however, similar research in marine foodwebs is lacking. This study combined environmental and biological Sr/Ca and Ba/Ca data from both terrestrial and marine settings from 62 published books, reports, and studies along with original data collected from 149 marine mammals (30 species) and 83 prey items (18 species) and found that variations in Sr/Ca and Ba/Ca ratios of biological and environmental samples are appreciably different in terrestrial and marine systems. In terrestrial systems, environmental sources account for most of the variations in Sr/Ca and Ba/Ca ratios. In contrast, environmental sources in marine systems (i.e., seawater) are comparatively invariant, meaning most of the variations in Sr/Ca and Ba/Ca ratios originate from biological processes. Marine consumers, particularly non-mammalian and mammalian vertebrates, show evidence of biopurification of Ca relative to Sr and Ba, similar to what is observed in terrestrial systems; however, unlike terrestrial systems, variations in Sr/Ca and Ba/Ca ratios of environmental sources are overprinted by bioaccumulation of Sr and Ba at the base of marine foodwebs. This demonstrates that in marine systems, spatial or temporal differences may have little to no effect on Sr/Ca and Ba/Ca ratios of marine vertebrates, making Sr/Ca, and to a lesser extent Ba/Ca, potentially useful global proxies for trophic level and dietary preferences of marine vertebrates.

  15. Application of Ca stable isotopes to long-term changes in the Ca cycle of a Northern Hardwood forest

    Science.gov (United States)

    Kurtz, A. C.; Takagi, K.; Bailey, S. W.; Bullen, T. D.

    2015-12-01

    The Hubbard Brook Ecosystem Study (New Hampshire, USA) presents an unusual opportunity for the application of innovative isotope methods in forest biogeochemistry. Changes in biogeochemical cycling resulting from decades of acid deposition, subsequent reductions in acid deposition, and a series of experimental treatments (harvesting, Ca amendment) have been studied continuously for 60 years at this site. Importantly, researchers have archived soil, water, and vegetation samples for much of the site's history. Our work seeks to complement earlier mass balance studies of Ca cycling by measuring Ca isotope ratios on archived samples. In the first component of our study, we examined the Ca isotopic response to an experimental clearcut in the early 1980's. Earlier work showed that the clearcut promoted dramatic loss of Ca from the watershed, indicated by a 5-fold increase in streamwater Ca concentrations. The mechanism for this loss was unclear as no resolvable changes in soil Ca pools were observed. Our work shows that streamwater dissolved Ca becomes isotopically lighter as Ca concentrations increase. These data are best accounted for by an increase in Ca loss from the soil cation exchange complex. Soil exchangeable δ44Ca itself evolves towards lighter values in the years following the experimental harvest. We interpret this as replenishment of the soil exchange complex by release of isotopically light Ca from root biomass. In the second component of our study, we examine decadal-scale changes in streamwater and soil Ca in an un-manipulated biogeochemical reference watershed. Historical data from Hubbard Brook show that streamwater Ca concentrations began decreasing sharply in the early 1970's, attributed to decreased deposition of both acidity and Ca with the passage of the Clean Air Act. Preliminary data indicate no resolvable change in the average δ44Ca of streamwater, with variability mostly attributable to discharge (flowpath control). Preliminary data

  16. Reaction process of monazite and bastnaesite mixed rare earth minerals calcined by CaO-NaCl-CaCl2

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The decomposition reactions of monazite and bastnaesite mixed rare earth minerals calcined by CaO-NaCl-CaCl2 were studied by means of TG-DTA and XRD. The results show that the process of the minerals decomposed by CaO involves two steps.The first step occurs in the temperature range of 425-540 ℃, and the main reactions are bastnaesite decomposition, i.e. REOF reacts with CaO to produce RE2O3 and CaF2, and Ce2O3 is oxidized to CeO2. During this step, CaCO3 is formed at about 500 ℃. The second step takes place in the temperature range of 610-700 ℃, and the reactions are monazite decomposition into RE2O3,Ca5F(PO4)3 and Ca3(PO4)2 by CaO and CaF2. In this process, the decomposition ability is improved because CaO from CaCO3decomposing has high chemical activity. In calcining process, the new formed Ca5F(PO4)3 restrains fluorine that can escape in form of gaseous compound. The decomposition ratio of the mixed rare earth minerals reaches 90.8% at 700 ℃.

  17. Modeling CaMKII-mediated regulation of L-type Ca2+ channels and ryanodine receptors in the heart

    Directory of Open Access Journals (Sweden)

    Joseph L Greenstein

    2014-04-01

    Full Text Available Excitation-contraction coupling (ECC in the cardiac myocyte is mediated by a number of highly integrated mechanisms of intracellular Ca2+ transport. Voltage- and Ca2+-dependent L-type Ca2+ channels (LCCs allow for Ca2+ entry into the myocyte, which then binds to nearby ryanodine receptors (RyRs and triggers Ca2+ release from the sarcoplasmic reticulum in a process known as Ca2+-induced Ca2+ release. The highly coordinated Ca2+-mediated interaction between LCCs and RyRs is further regulated by the cardiac isoform of the Ca2+/calmodulin-dependent protein kinase (CaMKII. Because CaMKII targets and modulates the function of many ECC proteins, elucidation of its role in ECC and integrative cellular function is challenging and much insight has been gained through the use of detailed computational models. Multiscale models that can both reconstruct the detailed nature of local signaling events within the cardiac dyad and predict their functional consequences at the level of the whole cell have played an important role in advancing our understanding of CaMKII function in ECC. Here, we review experimentally based models of CaMKII function with a focus on LCC and RyR regulation, and the mechanistic insights that have been gained through their application.

  18. Mitochondrial free [Ca2+] levels and the permeability transition

    OpenAIRE

    Vay, Laura; Hernández-SanMiguel, Esther; Domínguez Lobatón, María Carmen; Moreno, Alfredo; Montero, Mayte; Álvarez, Javier

    2009-01-01

    Producción Científica Mitochondrial Ca2+ activates many processes, from mitochondrial metabolism to opening of the permeability transition pore (PTP) and apoptosis. However, there is considerable controversy regarding the free mitochondrial [Ca2+] ([Ca2+]M) levels that can be attained during cell activation or even in mitochondrial preparations. Studies using fluorescent dyes (rhod-2 or similar), have reported that phosphate precipitation precludes [Ca2+]M from increasing above...

  19. 血清CEA、CA-125、CA-153、CA-199、CA242联合检测对消化道肿瘤诊断的临床意义

    Institute of Scientific and Technical Information of China (English)

    杨德辉; 周力; 张永宏; 张澜林; 谭玉洁; 王焰; 秦雯

    2006-01-01

    目的:探讨血清CEA、CA-125、CA-153、CA-199、CA242联合检测对消化道肿瘤诊断的临床意义。方法:采用酶联免疫吸附法(ELISA法)检测130例恶性消化道肿瘤患者(食管癌32例、胃癌34例、胰腺癌30例、大肠癌34例)血清CEA、CA-125、CA-153、CA-199、CA242水平。结果:表明上述四种消化道肿瘤的血清CEA、CA-125、CA-153、CA-199、CA242与对照组比较结果统计学上均有显著性差异(P〈0.01)。除胰腺癌之外,其余3种消化道肿瘤五项肿瘤标记物联合检测的阳性率均显著高于单一标志物检测(P〈0.05),分别为食管癌62.5%、胃癌85.2%、大肠癌82.3%。结论:血清CEA、CA-125、CA-153、CA-199、CA242联合检测可以显著提高消化道恶性肿瘤诊断的敏感性。

  20. CaMKII inhibition promotes neuronal apoptosis by transcriptionally upregulating Bim expression.

    Science.gov (United States)

    Zhao, Yiwei; Zhu, Lin; Yu, Shaojun; Zhu, Jing; Wang, Chong

    2016-09-28

    The effects of Ca/calmodulin-dependent protein kinase II (CaMKII) on neuronal apoptosis are complex and contradictory, and the underlying mechanisms remain unclear. Bcl-2-interacting mediator of cell death (Bim) is an important proapoptotic protein under many physiological and pathophysiological conditions. However, there is no evidence that CaMKII and Bim are mechanistically linked in neuronal apoptosis. In this study, we showed that CaMKII inhibition by the inhibitors KN-62 and myristoylated autocamtide-2-related inhibitory peptide promoted apoptosis in cerebellar granule neurons in a dose-dependent manner. CaMKII inhibition increased Bim protein and messenger RNA levels. The expression of early growth response factor-1, a transcription factor of Bim, was also induced by CaMKII inhibitors. These data suggested that CaMKII repressed the transcriptional expression of Bim. Moreover, knockdown of Bim using small interfering RNAs attenuated the proapoptotic effects of CaMKII inhibition. Taken together, this is the first report to show that CaMKII inhibition transcriptionally upregulates Bim expression to promote neuronal apoptosis, providing new insights into the proapoptotic mechanism of CaMKII inhibition.

  1. TRPV5, the gateway to Ca2+ homeostasis.

    NARCIS (Netherlands)

    Mensenkamp, A.R.; Hoenderop, J.G.J.; Bindels, R.J.M.

    2007-01-01

    Ca2+ homeostasis in the body is tightly controlled, and is a balance between absorption in the intestine, excretion via the urine, and exchange from bone. Recently, the epithelial Ca2+ channel (TRPV5) has been identified as the gene responsible for the Ca2+ influx in epithelial cells of the renal di

  2. Serum tetranectin and CA125 in endometrial adenocarcinoma

    DEFF Research Database (Denmark)

    Lundstrøm, M S; Høgdall, C K; Nielsen, Anette Lynge;

    2000-01-01

    in relation to tumor grade, stage and cancer survival. RESULTS: The CA125 levels correlated significantly with tumor stage. Dichotomized according to a cut-off level of 35 U/ml, CA125 significantly correlated with cancer death. Multivariate regression analysis of cancer survival time showed that CA125 > 35 U/ml...

  3. 33 CFR 110.210 - San Diego Harbor, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false San Diego Harbor, CA. 110.210... ANCHORAGE REGULATIONS Anchorage Grounds § 110.210 San Diego Harbor, CA. (a) The anchorage grounds. (1... Commander, Naval Base, San Diego, CA. The administration of these anchorages is exercised by the...

  4. Regulation of CaMKII signaling in cardiovascular disease

    Directory of Open Access Journals (Sweden)

    Mariya Yordanova Mollova

    2015-08-01

    Full Text Available Heart failure (HF is a major cause of death in the developed countries. (Murray and Lopez, 1996;Koitabashi and Kass, 2012. Adverse cardiac remodeling that precedes heart muscle dysfunction is characterized by a myriad of molecular changes affecting the cardiomyocyte. Among these, alterations in protein kinase pathways play often an important mediator role since they link upstream pathologic stress signaling with downstream regulatory programs and thus affect both the structural and functional integrity of the heart muscle. In the context of cardiac disease, a profound understanding for the overriding mechanisms that regulate protein kinase activity (protein-protein interactions, post-translational modifications, or targeting via anchoring proteins is crucial for the development of specific and effective pharmacological treatment strategies targeting the failing myocardium.In this review, we focus on several mechanisms of upstream regulation of Ca2+/Calmodulin-dependent kinase II (CaM Kinase II, CaMKII that play a relevant pathophysiological role in the development and progression of cardiovascular disease; precise targeting of these mechanisms might therefore represent novel and promising tools for prevention and treatment of HF.

  5. Distribution of Phosphorus between CaO-CaF2 Slag and Fe-C-P Melt

    Institute of Scientific and Technical Information of China (English)

    WANG Qing-xiang; ZHOU Jian-jian; DU Xiao-jian

    2005-01-01

    The equilibrium distribution ratio of phosphorus between CaO-CaF2 molten slag and Fe-C-P melt at 1450 ℃ was measured. The phosphate capacity of slag and the activity coefficient of phosphorus oxide were calculated.

  6. Preparation of 45Ca(HDEHP)n and (CaH{sub 1}50{sub 2})2 samples for liquid scintillation counting, compared to 45caCl{sub 2} results; Preparacion de Ca (HDEHP)n y (C{sub 8}H{sub 1}50{sub 2})2 marcados con 45Ca y estudio comparativo con 4 5ca Cl2 en medidas por centelleo liquido

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, L.; Arcos, J. M. los; Grau Malonda, A.

    1994-07-01

    A procedure for preparation of liquid scintillation counting organic samples of the Di-2-ethylhexyl phosphate calcium complex and the 2-ethylhexanoate calcium salt, labelled with 45Ca, is described. The chemical quench, the counting stability and spectral evolution of both compounds is studied in six scintillators,Toluene-alcohol, Dioxane-naphtalene, Hi safe II, Ultimate-Gold and Instagel, and compared to results obtained from a commercial solution of 4 5CaCl2. (Author) 7 refs.

  7. Solid state interactions in the systems CaO(CaCO3-Fe2O3 and CuFe2O4-CaO

    Directory of Open Access Journals (Sweden)

    Boyanov B.S.

    2005-01-01

    Full Text Available The solid state interactions in the systems CaO(CaCO3-Fe2O3 and CuFe2O4-CaO have been studied using X-ray diffraction analysis. The influence of the temperature on the ferrite formation process has been investigated in the range of 900-1200 oC and duration up to 360 min. It has been shown that a mixture of ferrites forms at 1000 oC and interaction of 240 min. The exchange reactions in the systems CuFe2O4-CaO and Cu0.5Zn0.5Fe2O4-CaO have been studied, too. It has been established that Ca2+ ions exchange Cu2+ and Zn2 partially and the solubility of copper and zinc in a 7 % sulfuric acid solution increases 10-15 times.

  8. The effect of CaF2 on thermodynamics of CaO-CaF2-SiO2(-MgO) slags

    Science.gov (United States)

    Choi, Chul-Hwan; Jo, Sung-Koo; Kim, Seon-Hyo; Lee, Kwang-Ro; Kim, Jeong-Tae

    2004-02-01

    To address the role of CaF2 in the CaO-CaF2-SiO2(-MgO) slag system employed for the production of low-pressure rotor steels, the thermodynamic aspects of the slag were investigated by equilibrating it with liquid iron at 1873 K in CaO or MgO crucibles. Presaturation of slag with an oxide block piece of CaO or MgO in a Pt crucible and application of a carbon paste to the outside of an oxide crucible were designed to prevent crucible failure during the slag-metal experiments. The liquidus isotherm and phase boundary of the preceding slag system were investigated using the slag-metal equilibria. Also, the effect of CaF2 on the sulfide capacity and the activity coefficient of Fe t O were of particular interest in controlling the sulfur level and cleanliness of low-pressure rotor steels.

  9. Citrus bergamia Risso Elevates Intracellular Ca2+ in Human Vascular Endothelial Cells due to Release of Ca2+ from Primary Intracellular Stores

    Directory of Open Access Journals (Sweden)

    Purum Kang

    2013-01-01

    , which was partially inhibited by a nonselective Ca2+ channel blocker La3+. In Ca2+-free extracellular solutions, BEO increased [Ca2+]i in a concentration-dependent manner, suggesting that BEO mobilizes intracellular Ca2+. BEO-induced [Ca2+]i increase was partially inhibited by a Ca2+-induced Ca2+ release inhibitor dantrolene, a phospholipase C inhibitor U73122, and an inositol 1,4,5-triphosphate (IP3-gated Ca2+ channel blocker, 2-aminoethoxydiphenyl borane (2-APB. BEO also increased [Ca2+]i in the presence of carbonyl cyanide m-chlorophenylhydrazone, an inhibitor of mitochondrial Ca2+ uptake. In addition, store-operated Ca2+ entry (SOC was potentiated by BEO. These results suggest that BEO mobilizes Ca2+ from primary intracellular stores via Ca2+-induced and IP3-mediated Ca2+ release and affect promotion of Ca2+ influx, likely via an SOC mechanism.

  10. Feedforward Inhibition Underlies the Propagation of Cholinergically Induced Gamma Oscillations from Hippocampal CA3 to CA1

    OpenAIRE

    Zemankovics, Rita; Veres, Judit M.; Oren, Iris; Hájos, Norbert

    2013-01-01

    Gamma frequency (30–80 Hz) oscillations are implicated in memory processing. Such rhythmic activity can be generated intrinsically in the CA3 region of the hippocampus from where it can propagate to the CA1 area. To uncover the synaptic mechanisms underlying the intrahippocampal spread of gamma oscillations, we recorded local field potentials, as well as action potentials and synaptic currents in anatomically identified CA1 and CA3 neurons during carbachol-induced gamma oscillations in mouse ...

  11. Reorientable dipolar CuCa antisite and anomalous screening in CaCu3Ti4O12

    Science.gov (United States)

    Delugas, Pietro; Alippi, Paola; Fiorentini, Vincenzo; Raineri, Vito

    2010-02-01

    Based on first-principles calculations, we show that the abundant CuCa antisite defect contributes sizably to dielectric screening in single-crystal CaCu3Ti4O12 . CuCa has a multi-minimum off-center equilibrium configuration, whereby it possesses a large and easily reorientable dipole moment. The low-temperature and frequency cut-off behavior of CuCa -induced response is consistent with experiment.

  12. Biological fractionation of stable Ca isotopes in Göttingen minipigs as a physiological model for Ca homeostasis in humans.

    Science.gov (United States)

    Heuser, Alexander; Eisenhauer, Anton; Scholz-Ahrens, Katharina E; Schrezenmeir, Jürgen

    2016-12-01

    In order to investigate fractionation of calcium (Ca) isotopes in vertebrates as a diagnostic tool to detect Ca metabolism dysfunction we analyzed the Ca isotopic composition (δ(44/40)Ca = [((44)Ca/(40)Ca)sample/((44)Ca/(40)Ca)reference]-1) of diet, faeces, blood, bones and urine from Göttingen minipigs, an animal model for human physiology. Samples of three groups were investigated: 1. control group (Con), 2. group with glucocorticosteroid induced osteoporosis (GIO) and 3. group with Ca and vitamin D deficiency induced osteomalacia (-CaD). In contrast to Con and GIO whose average δ(44/40)Cafaeces values (0.39 ± 0.13‰ and 0.28 ± 0.08‰, respectively) tend to be lower than their diet (0.47 ± 0.02‰), δ(44/40)Cafaeces of -CaD (-0.27 ± 0.21‰) was significantly lower than their δ(44/40)Cadiet (0.37 ± 0.03‰), but also lower than δ(44/40)Cafaeces of Con and GIO. We suggest that the low δ(44/40)Cafaeces of -CaD might be due to the contribution of isotopically light Ca from gastrointestinal fluids during gut passage. Assuming that this endogenous Ca source is a common physiologic feature, a fractionation during Ca absorption is also required for explaining δ(44/40)Cafaeces of Con and GIO. The δ(44/40)Caurine of all groups are high (>2.0‰) reflecting preferential renal reabsorption of light Ca isotopes. In Göttingen minipigs we found a Ca isotope fractionation between blood and bones (Δ(44/40)Cablood-bone) of 0.68 ± 0.15‰.

  13. Calbindin-D28K dynamically controls TRPV5-mediated Ca2+ transport.

    NARCIS (Netherlands)

    Lambers, T.T.; Mahieu, F.; Oancea, E.; Hoofd, L.J.C.; Lange, F. de; Mensenkamp, A.R.; Voets, T.; Nilius, B.; Clapham, D.E.; Hoenderop, J.G.J.; Bindels, R.J.M.

    2006-01-01

    In Ca(2+)-transporting epithelia, calbindin-D(28K) (CaBP(28K)) facilitates Ca(2+) diffusion from the luminal Ca(2+) entry side of the cell to the basolateral side, where Ca(2+) is extruded into the extracellular compartment. Simultaneously, CaBP(28K) provides protection against toxic high Ca(2+) lev

  14. Ultrastructural and immunohistochemical localization of plasma membrane Ca2+-ATPase 4 in Ca2+-transporting epithelia

    DEFF Research Database (Denmark)

    Alexander, R Todd; Beggs, Megan R; Zamani, Reza;

    2015-01-01

    role in transcellular Ca(2+) flux and investigated the localization and regulation of Pmca4 in Ca(2+)-transporting epithelia. Using antibodies directed specifically against Pmca4, we found it expressed only in the smooth muscle layer of mouse and human intestine, while pan-specific Pmca antibodies...... the cortical thick ascending limbs, macula densa, and early distal tubules as well as smooth muscle layers surrounding renal vessels. In human kidney, a similar pattern of distribution was observed, with highest PMCA4 expression in NCC positive tubules. Electron microscopy demonstrated Pmca4 localization...... in distal nephron cells at both the basolateral membrane and intracellular perinuclear compartments, but not submembranous vesicles, suggesting rapid trafficking to the plasma membrane is unlikely to occur in vivo. Pmca4 expression was not altered by perturbations in Ca(2+) balance, pointing...

  15. An ID-like current that is downregulated by Ca2+ modulates information coding at CA3-CA3 synapses in the rat hippocampus.

    Science.gov (United States)

    Saviane, Chiara; Mohajerani, Majid H; Cherubini, Enrico

    2003-10-15

    Voltage-gated K+ channels localised on presynaptic nerve terminals control information coding by modulating presynaptic firing and synaptic efficacy in target neurones. We found that at CA3-CA3 connections in hippocampal slice cultures, a fast-activating, slowly inactivating K+ conductance similar to the so-called delay current (ID) is responsible for the delayed appearance of the first spike upon membrane depolarisation, for action potential repolarisation and for modulation of transmitter release. The ID-like current was downregulated by intracellular Ca2+, as indicated by the increased delay in the appearance of the first action potential following either the block of Ca2+ flux through voltage-dependent Ca2+ channels with Cd2+ or replacement of the bathing solution with one devoid of Ca2+. In both cases, this effect was reversed by blocking this conductance with a low concentration of 4-aminopyridine (4-AP, 10-50 muM). Application of 4-AP shortened the delay to the first spike generation, prevented the effect of Cd2+ and increased the spike duration. The earlier appearance of the first action potential was also observed in the presence of dendrotoxin-1 (100 nM). In voltage-clamp experiments larger currents were recorded in the absence of extracellular Ca2+, thus confirming the downregulation of the ID-like current by Ca2+ due to the positive shift of its inactivation. Spike broadening was associated with an enhancement of synaptic efficacy in target neurones, as assessed by the increase in EPSC amplitude and in the percentage of successes. Moreover, in the presence of 4-AP, EPSCs appeared with a longer latency and were more scattered. This conductance is therefore crucial for setting the timing and strength of synaptic transmission at CA3-CA3 connections. It is conceivable that switching off ID by increasing intracellular Ca2+ following activity-dependent processes may facilitate network synchronisation and crosstalk between CA3 pyramidal cells, leading to

  16. CORRELATION OF {sup 48}Ca, {sup 50}Ti, AND {sup 138}La HETEROGENEITY IN THE ALLENDE REFRACTORY INCLUSIONS

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hsin-Wei; Lee, Typhoon; Lee, Der-Chuen; Chen, Jiang-Chang, E-mail: hart.chen@bristol.ac.uk [Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan, ROC (China)

    2015-06-10

    Precise determinations of {sup 48}Ca anomalies in Allende calcium–aluminum-rich inclusions (CAIs) are reported in this work. There are endemic positive {sup 48}Ca/{sup 44}Ca anomalies in all analyzed CAIs after normalization to {sup 42}Ca/{sup 44}Ca, and it is clearly shown that there is no simple correlation between {sup 48}Ca/{sup 44}Ca and {sup 50}Ti/{sup 48}Ti anomalies, in agreement with Jungck et al. Compared to the {sup 48}Ca/{sup 44}Ca versus {sup 50}Ti/{sup 48}Ti correlation line defined by differentiated meteorites, reported by Chen et al., the CAIs plot to elevated {sup 50}Ti/{sup 48}Ti. Assuming the {sup 48}Ca/{sup 44}Ca anomalies of both CAIs and differentiated meteorites came from the same source, excess {sup 50}Ti anomalies in CAIs can be calculated by subtracting the part associated with {sup 48}Ca/{sup 44}Ca. These excesses show a linear correlation with {sup 138}La anomalies, a neutrino-process nuclide. According to current stellar nucleosynthetic models, we therefore suggest that the solar system {sup 48}Ca, {sup 50}Ti, and {sup 138}La isotopic variations are made of mixtures between grains condensed from ejecta of neutron-rich accretion-induced SNe Ia and the O/Ne–O/C zone of core-collapse SNe II.

  17. Chloroquine Inhibits Ca2+ Signaling in Murine CD4+ Thymocytes

    Directory of Open Access Journals (Sweden)

    Jin-Chao Xu

    2015-04-01

    Full Text Available Background/Aims: Bitter-tasting chloroquine can suppress T cell activation by inhibiting Ca2+ signaling. However, the mechanism of inhibition remains largely unclear. Methods: In this study, CD4+ T cells were isolated from the thymus, and the calcium content of CD4+ thymocytes was measured using fura-2 AM and a TILL imaging system. Pyrazole-3 (Pyr3, thapsigargin (TG, and caffeine were used to assess the effects of chloroquine on the intracellular Ca2+ content of CD4+ T cells. Results: In murine CD4+ thymocytes, chloroquine decreased the TG-triggered intracellular Ca2+ increase in a dose-dependent manner. In the absence of chloroquine under Ca2+-free conditions (0 mM Ca2+ and 0.5 mM EGTA, TG induced a transient Ca2+ increase. After restoration of the extracellular Ca2+ concentration to 2 mM, a dramatic Ca2+ increase occurred. This elevation was completely blocked by chloroquine and was markedly inhibited by Pyr3, a selective antagonist of transient receptor potential C3 (TRPC3 channel and stromal interaction molecule (STIM/Orai channel. Furthermore, the TG-induced transient Ca2+ increase under Ca2+-free conditions was eliminated in the presence of chloroquine. Chloroquine also blocked the dialyzed inositol-1,4,5-trisphosphate (IP3-induced intracellular Ca2+ increase. However, chloroquine was not able to decrease the caffeine-induced Ca2+ increase. Conclusion: These data indicate that chloroquine inhibits the elevation of intracellular Ca2+ in thymic CD4+ T cells by inhibiting IP3 receptor-mediated Ca2+ release from intracellular stores and TRPC3 channel-mediated and/or STIM/Orai channel-mediated Ca2+ influx.

  18. Ca2+-Regulated Photoproteins: Effective Immunoassay Reporters

    Directory of Open Access Journals (Sweden)

    Ludmila A. Frank

    2010-12-01

    Full Text Available Ca2+-regulated photoproteins of luminous marine coelenterates are of interest and a challenge for researchers as a unique bioluminescent system and as a promising analytical instrument for both in vivo and in vitro applications. The proteins are comprehensively studied as to biochemical properties, tertiary structures, bioluminescence mechanism, etc. This knowledge, along with available recombinant proteins serves the basis for development of unique bioluminescent detection systems that are “self-contained”, triggerable, fast, highly sensitive, and non-hazardous. In the paper, we focus on the use of photoproteins as reporters in binding assays based on immunological recognition element—bioluminescent immunoassay and hybridization immunoassay, their advantages and prospects.

  19. Superdeformed and Triaxial States in ^{42}Ca.

    Science.gov (United States)

    Hadyńska-Klȩk, K; Napiorkowski, P J; Zielińska, M; Srebrny, J; Maj, A; Azaiez, F; Valiente Dobón, J J; Kicińska-Habior, M; Nowacki, F; Naïdja, H; Bounthong, B; Rodríguez, T R; de Angelis, G; Abraham, T; Anil Kumar, G; Bazzacco, D; Bellato, M; Bortolato, D; Bednarczyk, P; Benzoni, G; Berti, L; Birkenbach, B; Bruyneel, B; Brambilla, S; Camera, F; Chavas, J; Cederwall, B; Charles, L; Ciemała, M; Cocconi, P; Coleman-Smith, P; Colombo, A; Corsi, A; Crespi, F C L; Cullen, D M; Czermak, A; Désesquelles, P; Doherty, D T; Dulny, B; Eberth, J; Farnea, E; Fornal, B; Franchoo, S; Gadea, A; Giaz, A; Gottardo, A; Grave, X; Grȩbosz, J; Görgen, A; Gulmini, M; Habermann, T; Hess, H; Isocrate, R; Iwanicki, J; Jaworski, G; Judson, D S; Jungclaus, A; Karkour, N; Kmiecik, M; Karpiński, D; Kisieliński, M; Kondratyev, N; Korichi, A; Komorowska, M; Kowalczyk, M; Korten, W; Krzysiek, M; Lehaut, G; Leoni, S; Ljungvall, J; Lopez-Martens, A; Lunardi, S; Maron, G; Mazurek, K; Menegazzo, R; Mengoni, D; Merchán, E; Mȩczyński, W; Michelagnoli, C; Mierzejewski, J; Million, B; Myalski, S; Napoli, D R; Nicolini, R; Niikura, M; Obertelli, A; Özmen, S F; Palacz, M; Próchniak, L; Pullia, A; Quintana, B; Rampazzo, G; Recchia, F; Redon, N; Reiter, P; Rosso, D; Rusek, K; Sahin, E; Salsac, M-D; Söderström, P-A; Stefan, I; Stézowski, O; Styczeń, J; Theisen, Ch; Toniolo, N; Ur, C A; Vandone, V; Wadsworth, R; Wasilewska, B; Wiens, A; Wood, J L; Wrzosek-Lipska, K; Ziȩbliński, M

    2016-08-01

    Shape parameters of a weakly deformed ground-state band and highly deformed slightly triaxial sideband in ^{42}Ca were determined from E2 matrix elements measured in the first low-energy Coulomb excitation experiment performed with AGATA. The picture of two coexisting structures is well reproduced by new state-of-the-art large-scale shell model and beyond-mean-field calculations. Experimental evidence for superdeformation of the band built on 0_{2}^{+} has been obtained and the role of triaxiality in the A∼40 mass region is discussed. Furthermore, the potential of Coulomb excitation as a tool to study superdeformation has been demonstrated for the first time.

  20. 拯救老兵CA

    Institute of Scientific and Technical Information of China (English)

    威廉·麦克拉肯

    2011-01-01

    @@ 是的,CA Technologies(冠群电脑)还活着.这家由美籍华人王嘉廉创办的软件公司,曾经风光无限,甚至一度有比肩微软的可能.然而混乱的内部管理与频繁的决策失误,造成了公司业绩低迷,随即也引发了股东间的权力纷争.

  1. Mechanics of Old Faithful Geyser, Calistoga, CA

    Science.gov (United States)

    Rudolph, M.L.; Manga, M.; Hurwitz, Shaul; Johnston, Malcolm J.; Karlstrom, L.; Wang, Chun-Yong

    2012-01-01

    In order to probe the subsurface dynamics associated with geyser eruptions, we measured ground deformation at Old Faithful Geyser of Calistoga, CA. We present a physical model in which recharge during the period preceding an eruption is driven by pressure differences relative to the aquifer supplying the geyser. The model predicts that pressure and ground deformation are characterized by an exponential function of time, consistent with our observations. The geyser's conduit is connected to a reservoir at a depth of at least 42 m, and pressure changes in the reservoir can produce the observed ground deformations through either a poroelastic or elastic mechanical model.

  2. Superdeformed and Triaxial States in 42Ca

    Science.gov (United States)

    Hadyńska-KlÈ©k, K.; Napiorkowski, P. J.; Zielińska, M.; Srebrny, J.; Maj, A.; Azaiez, F.; Valiente Dobón, J. J.; Kicińska-Habior, M.; Nowacki, F.; Naïdja, H.; Bounthong, B.; Rodríguez, T. R.; de Angelis, G.; Abraham, T.; Anil Kumar, G.; Bazzacco, D.; Bellato, M.; Bortolato, D.; Bednarczyk, P.; Benzoni, G.; Berti, L.; Birkenbach, B.; Bruyneel, B.; Brambilla, S.; Camera, F.; Chavas, J.; Cederwall, B.; Charles, L.; Ciemała, M.; Cocconi, P.; Coleman-Smith, P.; Colombo, A.; Corsi, A.; Crespi, F. C. L.; Cullen, D. M.; Czermak, A.; Désesquelles, P.; Doherty, D. T.; Dulny, B.; Eberth, J.; Farnea, E.; Fornal, B.; Franchoo, S.; Gadea, A.; Giaz, A.; Gottardo, A.; Grave, X.; GrÈ©bosz, J.; Görgen, A.; Gulmini, M.; Habermann, T.; Hess, H.; Isocrate, R.; Iwanicki, J.; Jaworski, G.; Judson, D. S.; Jungclaus, A.; Karkour, N.; Kmiecik, M.; Karpiński, D.; Kisieliński, M.; Kondratyev, N.; Korichi, A.; Komorowska, M.; Kowalczyk, M.; Korten, W.; Krzysiek, M.; Lehaut, G.; Leoni, S.; Ljungvall, J.; Lopez-Martens, A.; Lunardi, S.; Maron, G.; Mazurek, K.; Menegazzo, R.; Mengoni, D.; Merchán, E.; MÈ©czyński, W.; Michelagnoli, C.; Mierzejewski, J.; Million, B.; Myalski, S.; Napoli, D. R.; Nicolini, R.; Niikura, M.; Obertelli, A.; Özmen, S. F.; Palacz, M.; Próchniak, L.; Pullia, A.; Quintana, B.; Rampazzo, G.; Recchia, F.; Redon, N.; Reiter, P.; Rosso, D.; Rusek, K.; Sahin, E.; Salsac, M.-D.; Söderström, P.-A.; Stefan, I.; Stézowski, O.; Styczeń, J.; Theisen, Ch.; Toniolo, N.; Ur, C. A.; Vandone, V.; Wadsworth, R.; Wasilewska, B.; Wiens, A.; Wood, J. L.; Wrzosek-Lipska, K.; ZiÈ©bliński, M.

    2016-08-01

    Shape parameters of a weakly deformed ground-state band and highly deformed slightly triaxial sideband in 42Ca were determined from E 2 matrix elements measured in the first low-energy Coulomb excitation experiment performed with AGATA. The picture of two coexisting structures is well reproduced by new state-of-the-art large-scale shell model and beyond-mean-field calculations. Experimental evidence for superdeformation of the band built on 02+ has been obtained and the role of triaxiality in the A ˜40 mass region is discussed. Furthermore, the potential of Coulomb excitation as a tool to study superdeformation has been demonstrated for the first time.

  3. Autophagy blockade sensitizes the anticancer activity of CA-4 via JNK-Bcl-2 pathway

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yangling; Luo, Peihua; Wang, Jincheng; Dai, Jiabin; Yang, Xiaochun; Wu, Honghai; Yang, Bo, E-mail: yang924@zju.edu.cn; He, Qiaojun, E-mail: qiaojunhe@zju.edu.cn

    2014-01-15

    Combretastatin A-4 (CA-4) has already entered clinical trials of solid tumors over ten years. However, the limited anticancer activity and dose-dependent toxicity restrict its clinical application. Here, we offered convincing evidence that CA-4 induced autophagy in various cancer cells, which was demonstrated by acridine orange staining of intracellular acidic vesicles, the degradation of p62, the conversion of LC3-I to LC3-II and GFP-LC3 punctate fluorescence. Interestingly, CA-4-mediated apoptotic cell death was further potentiated by pretreatment with autophagy inhibitors (3-methyladenine and bafilomycin A1) or small interfering RNAs against the autophagic genes (Atg5 and Beclin 1). The enhanced anticancer activity of CA-4 and 3-MA was further confirmed in the SGC-7901 xenograft tumor model. These findings suggested that CA-4-elicited autophagic response played a protective role that impeded the eventual cell death while autophagy inhibition was expected to improve chemotherapeutic efficacy of CA-4. Meanwhile, CA-4 treatment led to phosphorylation/activation of JNK and JNK-dependent phosphorylation of Bcl-2. Importantly, JNK inhibitor or JNK siRNA inhibited autophagy but promoted CA-4-induced apoptosis, indicating a key requirement of JNK-Bcl-2 pathway in the activation of autophagy by CA-4. We also identified that pretreatment of Bcl-2 inhibitor (ABT-737) could significantly enhance anticancer activity of CA-4 due to inhibition of autophagy. Taken together, our data suggested that the JNK-Bcl-2 pathway was considered as the critical regulator of CA-4-induced protective autophagy and a potential drug target for chemotherapeutic combination. - Highlights: • Autophagy inhibition could be a potential for combretastatin A-4 antitumor efficacy. • The JNK-Bcl-2 pathway plays a critical role in CA-4-induced autophagy. • ABT-737 enhances CA-4 anticancer activity due to inhibition of autophagy.

  4. Differential CaMKII regulation by voltage-gated calcium channels in the striatum.

    Science.gov (United States)

    Pasek, Johanna G; Wang, Xiaohan; Colbran, Roger J

    2015-09-01

    Calcium signaling regulates synaptic plasticity and many other functions in striatal medium spiny neurons to modulate basal ganglia function. Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) is a major calcium-dependent signaling protein that couples calcium entry to diverse cellular changes. CaMKII activation results in autophosphorylation at Thr286 and sustained calcium-independent CaMKII activity after calcium signals dissipate. However, little is known about the mechanisms regulating striatal CaMKII. To address this, mouse brain slices were treated with pharmacological modulators of calcium channels and punches of dorsal striatum were immunoblotted for CaMKII Thr286 autophosphorylation as an index of CaMKII activation. KCl depolarization increased levels of CaMKII autophosphorylation ~2-fold; this increase was blocked by an LTCC antagonist and was mimicked by treatment with pharmacological LTCC activators. The chelation of extracellular calcium robustly decreased basal CaMKII autophosphorylation within 5min and increased levels of total CaMKII in cytosolic fractions, in addition to decreasing the phosphorylation of CaMKII sites in the GluN2B subunit of NMDA receptors and the GluA1 subunit of AMPA receptors. We also found that the maintenance of basal levels of CaMKII autophosphorylation requires low-voltage gated T-type calcium channels, but not LTCCs or R-type calcium channels. Our findings indicate that CaMKII activity is dynamically regulated by multiple calcium channels in the striatum thus coupling calcium entry to key downstream substrates.

  5. Ca(2+) homeostasis in the budding yeast Saccharomyces cerevisiae: Impact of ER/Golgi Ca(2+) storage.

    Science.gov (United States)

    D'hooge, Petra; Coun, Catherina; Van Eyck, Vincent; Faes, Liesbeth; Ghillebert, Ruben; Mariën, Lore; Winderickx, Joris; Callewaert, Geert

    2015-08-01

    Yeast has proven to be a powerful tool to elucidate the molecular aspects of several biological processes in higher eukaryotes. As in mammalian cells, yeast intracellular Ca(2+) signalling is crucial for a myriad of biological processes. Yeast cells also bear homologs of the major components of the Ca(2+) signalling toolkit in mammalian cells, including channels, co-transporters and pumps. Using yeast single- and multiple-gene deletion strains of various plasma membrane and organellar Ca(2+) transporters, combined with manipulations to estimate intracellular Ca(2+) storage, we evaluated the contribution of individual transport systems to intracellular Ca(2+) homeostasis. Yeast strains lacking Pmr1 and/or Cod1, two ion pumps implicated in ER/Golgi Ca(2+) homeostasis, displayed a fragmented vacuolar phenotype and showed increased vacuolar Ca(2+) uptake and Ca(2+) influx across the plasma membrane. In the pmr1Δ strain, these effects were insensitive to calcineurin activity, independent of Cch1/Mid1 Ca(2+) channels and Pmc1 but required Vcx1. By contrast, in the cod1Δ strain increased vacuolar Ca(2+) uptake was not affected by Vcx1 deletion but was largely dependent on Pmc1 activity. Our analysis further corroborates the distinct roles of Vcx1 and Pmc1 in vacuolar Ca(2+) uptake and point to the existence of not-yet identified Ca(2+) influx pathways.

  6. The Role of Extracellular Ca2+Influx, Intracellular Ca2+ Release and Calmodulin in Mouse Egg Fertilization

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The effects of various Ca2+-modifying drugs on moue egg fertilization were studied. Ca2+ chelator, ethylen glycol-bis-(2-aminoethyl)-tetracetic acid (EGTA) ,and calmodulin (CaM) antagonist,trifluoperzaine (TFP) ,inhibited fertilization in a dose-dependent manner,whild Ca2+ channel bolcker,verapamil ,did not have any effect. When intracellular Ca2+ release was blocked by 8-(N, N-diethylamino) octy1-3,4,5-trimethoxy- benzonate (TMB-8) or the Ca2+ oscillations were inhibited by an inhibitor of endoplasmic reticulum Ca2+-AT- Pase,thapsigargin,the second polar body emission and pronuclear formation were significantly decreased. In contrast,inhibition of intracellular Ca2+ release via bolckage of inositol 1,4,5-triphosphate (IP3) production by neomycin or lithium did not affect fertilization. The results sugest that both extracellular influx,intracellu- lar Ca2+ release and CaM activation are required for normal fertilization. However ,extracellular influx through voltage-gated Ca2+ channel and intracellular release induced by IP3 are not the only pathways for producing Ca2+ transients in moue eggs.

  7. The Role of Extracellular Ca2+ Influx,Intracellular Ca2+ Release and Calmodulin in Mouse Egg Fertilization

    Institute of Scientific and Technical Information of China (English)

    SunQing-yuan; TanJing-he; 等

    1999-01-01

    The effects of various Ca2+-modifying drugs on moue egg fertilization were studied.Ca2+ chelator,ethylen glycol-bis-(2-aminoethyl)-tetracetic acid(EGTA),and calmodulin(CaM) antagonist,trifluoperzaine (TFP),inhibited fertilization in a dose-dependent manner,whild Ca2+ channel bolcker,verspamil,did not have any effect.When intracellular Ca2+ release was blocked by 8-(N,N-diethylamino) octy 1-3,4,5-trimethoxy-benzonate(TME-8) or the Ca2+ oscillations were inhibited by an inhibitor of endoplasmic reticulum Ca2+-At-Pase,thapsigargin,the second polar body emission and pronuclear formation were significantly decreased.In contrast,inhibition of intracellular Ca2+ release via bolckage of inositol 1,4,5-triphosphate (IP3) production by neomycin or lithium did not affect fertilization.The results sugest that both extracellular influx,intracellular Ca2+ release and CaM activation are required for mormal fertilization.However,extracellular influx through voltage-gated Ca2+ channel and intracellular release induced by IP3 and not the only pathways for producing Ca2+ transients in moue eggs.

  8. Differential contribution of cytoplasmic Ca2+ and Ca2+ influx to gamete fusion and egg activation in maize.

    Science.gov (United States)

    Antoine, A F; Faure, J E; Dumas, C; Feijó, J A

    2001-12-01

    In multicellular organisms, gamete fusion triggers a set of events, collectively known as egg activation, that leads to the development of a new individual. Every species that has been studied shows at least one rise in cytoplasmic Ca2+ concentration ([Ca2+]Cyt) after gamete fusion which is believed to be involved in activation. Yet the source and regulation of this Ca2+ signal and the way it is transduced inside the zygote are controversial. In higher plants, in vitro fertilization (IVF) has enabled the description of a rise in [Ca2+]Cyt (ref. 4) that is sufficient for activation, and of a Ca2+ influx that spreads as a wavefront from the fusion site The relationship between these two responses is unknown. Using a new combination of methods that simultaneously monitor the extracellular flux with a Ca2+-vibrating probe, and [Ca2+]Cyt by widefield imaging, we directly determined that the Ca2+ influx precedes the [Ca2+]Cyt elevation by 40-120 s. In addition, results from experiments using the Ca2+-channel inhibitor gadolinium (Gd3+) suggest that the Ca2+ influx may be necessary for sperm incorporation. We also present evidence for a putative sperm-dependent Gd3+-insensitive localized Ca2+ influx confined to the fusion point.

  9. Photolysis of caged compounds: studying Ca(2+) signaling and activation of Ca(2+)-dependent ion channels.

    Science.gov (United States)

    Almassy, Janos; Yule, David I

    2013-01-01

    A wide variety of signaling molecules have been chemically modified by conjugation to a photolabile chromophore to render the substance temporarily biologically inert. Subsequent exposure to ultraviolet (UV) light can release the active moiety from the "caged" precursor in an experimentally controlled manner. This allows the concentration of active molecule to be precisely manipulated in both time and space. These techniques are particularly useful in experimental protocols designed to investigate the mechanisms underlying Ca(2+) signaling and the activation of Ca(2+)-dependent effectors.

  10. Homer proteins in Ca²⁺ entry.

    Science.gov (United States)

    Jardin, Isaac; López, José J; Berna-Erro, Alejandro; Salido, Ginés M; Rosado, Juan A

    2013-06-01

    The Homer family of proteins consists of three adaptor proteins, Homer1, Homer2 and Homer3, each with various isoforms. Homer1 family presents an EVH1 domain, a coiled coil domain and two leucine zipper domains. Homer proteins regulate a number of Ca2+-handling proteins, including transient receptor potential channels and other Ca2+-permeable channels, ionotropic and metabotropic glutamate receptors, shank scaffolding proteins or endoplasmic reticulum Ca2+ release channels. This review article focuses on the association of Homer 1 proteins with Ca2+-handling proteins and their role on intracellular Ca2+-homeostasis.

  11. ATP hydrolysis is critically required for function of CaV1.3 channels in cochlear inner hair cells via fueling Ca2+ clearance.

    Science.gov (United States)

    Weiler, Simon; Krinner, Stefanie; Wong, Aaron B; Moser, Tobias; Pangršič, Tina

    2014-05-14

    Sound encoding is mediated by Ca(2+) influx-evoked release of glutamate at the ribbon synapse of inner hair cells. Here we studied the role of ATP in this process focusing on Ca(2+) current through CaV1.3 channels and Ca(2+) homeostasis in mouse inner hair cells. Patch-clamp recordings and Ca(2+) imaging demonstrate that hydrolyzable ATP is essential to maintain synaptic Ca(2+) influx in inner hair cells via fueling Ca(2+)-ATPases to avoid an increase in cytosolic [Ca(2+)] and subsequent Ca(2+)/calmodulin-dependent inactivation of CaV1.3 channels.

  12. Effects of the removal of extracellular Ca2+ on [Ca2+]i responses to FCCP and acetate in carotid body glomus cells of adult rabbits.

    Science.gov (United States)

    Sato, M

    1997-09-12

    The effects of the removal of extracellular Ca2+ on the responses of cytosolic concentrations of Ca2+ ([Ca2+]i) to acidic stimuli, a protonophore carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) and an organic acid acetate, were examined in clusters of cultured carotid body glomus cells of adult rabbits using fura-2 microfluorometry. Application of FCCP (1 microM) induced an increase in [Ca2+]i (mean +/- S.E.M., 108 +/- 14%). After withdrawal of the protonophore the increased [Ca2+]i returned slowly to a resting level. The [Ca2+]i response was attenuated by an inorganic Ca2+ channel antagonist Ni2+ (2 mM) by 81 +/- 4%, and by an L-type voltage-gated Ca2+ channel antagonist D600 (10 microM) by 53 +/- 13%. The removal of extracellular Ca2+ eliminated the [Ca2+]i response in 71% of the tested cells (n = 17), and depressed it by 68 +/- 6% in the rest. Recovery following stimulation with FCCP in the absence of Ca2+ reversibly produced a rapid and large rise in [Ca2+]i, referred to as a [Ca2+]i rise after Ca2+-free/FCCP. The magnitude of a [Ca2+]i rise after Ca2+-free/FCCP (285 +/- 28%, P < 0.05) was larger than that of an increase in [Ca2+]i induced by FCCP in the presence of Ca2+ and had a correlation with the intensity of the suppression of the [Ca2+]i response by Ca2+ removal. A [Ca2+]i rise after Ca2+-free/FCCP was inhibited mostly by D600. Similarly, recovery following exposure to acetate in the absence of Ca2+ caused a rise in [Ca2+]i, referred to as a [Ca2+]i rise after Ca2+-free/acetate which was sensitive to D600. The magnitude of the [Ca2+]i rise was larger than that of a change in [Ca2+]i caused by acetate in the presence of Ca2+. These results suggest that FCCP-induced increase in [Ca2+]i was, in most cells, due to Ca2+ influx via L-type voltage-gated Ca2+ channels and, in some cells, due to both Ca2+ influx and Ca2+ release from internal Ca2+ pool. The removal of extracellular Ca2+ might modify [Ca2+]i responses to acidic stimuli, causing [Ca2+]i

  13. Inhibitory Gating of Input Comparison in the CA1 Microcircuit.

    Science.gov (United States)

    Milstein, Aaron D; Bloss, Erik B; Apostolides, Pierre F; Vaidya, Sachin P; Dilly, Geoffrey A; Zemelman, Boris V; Magee, Jeffrey C

    2015-09-23

    Spatial and temporal features of synaptic inputs engage integration mechanisms on multiple scales, including presynaptic release sites, postsynaptic dendrites, and networks of inhibitory interneurons. Here we investigate how these mechanisms cooperate to filter synaptic input in hippocampal area CA1. Dendritic recordings from CA1 pyramidal neurons reveal that proximal inputs from CA3 as well as distal inputs from entorhinal cortex layer III (ECIII) sum sublinearly or linearly at low firing rates due to feedforward inhibition, but sum supralinearly at high firing rates due to synaptic facilitation, producing a high-pass filter. However, during ECIII and CA3 input comparison, supralinear dendritic integration is dynamically balanced by feedforward and feedback inhibition, resulting in suppression of dendritic complex spiking. We find that a particular subpopulation of CA1 interneurons expressing neuropeptide Y (NPY) contributes prominently to this dynamic filter by integrating both ECIII and CA3 input pathways and potently inhibiting CA1 pyramidal neuron dendrites.

  14. The fertilization—induced Ca2+ oscillation in mouse oocytes is cytoplasmic maturation dependent

    Institute of Scientific and Technical Information of China (English)

    DENGMANQI; FANGZHENSUN

    1996-01-01

    Mature eggs (at metaphase II stage) produce a series of Ca2+ oscillation at fertilization.To define whether the fertilization-induced Ca2+ oscillation is restrict to the metaphase II eggs and cell cycle dependent,mouse oocytes at prophase I (arrested at germinal vesicle stage),metaphase I,metaphase II,as well as the pronuclear embryos at interphase of the first mitotic division derived from fertilization of parthenogenetic activation were inseminated after removal of zona pellucida,The results show that the fertilization-induced Ca2+ oscillation is not specific to metaphase II eggs.This is supported by the fact that immature oocytes generated the Ca2+ oscillations at fertilization regardless of their nuclear progression from prophase I to metaphase I (in vitro matured) stage.More interestingly,it was first found that pronuclear embryos at interphase derived from parthenogenetic activation showed Ca2+ oscillations in response to fertilization while the zygotes at interphase did not after reinsemination or intracytoplasmic injection of sperm extracts which induce Ca2+ oscillations in MII eggs.This suggests that the ability of oocytes to generate Ca2+ oscillation in response to sperm penetration is not regulated in a cell cycle dependent manner but dependent on the cytoplasmic maturation.

  15. Influence of isolation media on synaptosomal properties: Intracellular pH, pCa, and Ca sup 2+ uptake

    Energy Technology Data Exchange (ETDEWEB)

    Bandeira-Duarte, C.; Carvalho, C.A.; Cragoe Junior, E.J.; Carvalho, A.P. (Univ. of Coimbra (Portugal))

    1990-03-01

    Preparations of synaptosomes isolated in sucrose or in Na(+)-rich media were compared with respect to internal pH (pHi), internal Ca{sup 2+} concentration ((Ca{sup 2+})i), membrane potential and {sup 45}Ca{sup 2+} uptake due to K+ depolarization and Na{sup +}/Ca{sup 2+} exchange. We found that synaptosomes isolated in sucrose media have a pHi of 6.77 +/- 0.04 and a (Ca{sup 2+})i of about 260 nM, whereas synaptosomes isolated in Na(+)-rich ionic media have a pHi of 6.96 +/- 0.07 and a (Ca{sup 2+})i of 463 nM, but both types of preparations have similar membrane potentials of about -50 mV when placed in choline media. The sucrose preparation takes up Ca{sup 2+} only by voltage sensitive calcium channels (VSCC'S) when K(+)-depolarized, while the Na(+)-rich synaptosomes take up {sup 45}Ca{sup 2+} both by VSCC'S and by Na{sup +}/Ca{sup 2+} exchange. The amiloride derivative 2',4'-dimethylbenzamil (DMB), at 30 microM, inhibits both mechanisms of Ca{sup 2+} influx, but 5-(N-4-chlorobenzyl)-2',4' dimethylbenzamil (CBZ-DMB), at 30 microM, inhibits the Ca{sup 2+} uptake by VSCC'S, but not by Na+/Ca2+ exchange. Thus, DMB and CBZ-DMB permit distinguishing between Ca{sup 2+} flux through channels and through Na{sup +}/Ca{sup 2+} exchange. We point out that the different properties of the two types of synaptosomes studied account for some of the discrepancies in results reported in the literature for studies of Ca{sup 2+} fluxes and neurotransmitter release by different types of preparations of synaptosomes.

  16. Vanadate oligomer inhibition of passive and active Ca2+ translocation by the Ca2+ pump of sarcoplasmic reticulum.

    Science.gov (United States)

    Aureliano, M

    2000-05-30

    'Monovanadate' containing mainly monomeric, dimeric and tetrameric vanadate species or 'decavanadate', containing mainly decameric vanadate species inhibits the passive and the active efflux of Ca2+ through the sarcoplasmic reticulum calcium pump. When the efflux of Ca2+ by sarcoplasmic reticulum vesicles is not associated with ATP synthesis both vanadate solutions inhibit the passive efflux of Ca2+. However, only 'decavanadate' exerts noticeable effects when the efflux of Ca2+ is associated with ATP synthesis being the active efflux of Ca2+ almost completely inhibited by decameric species concentration as low as 40 microM.

  17. The mitochondrial Na+/Ca2+ exchanger plays a key role in the control of cytosolic Ca2+ oscillations

    OpenAIRE

    Hernández-San Miguel, Esther; Vay, Laura; Santo Domingo, Jaime; Domínguez Lobatón, María Carmen; Moreno, Alfredo; Montero, Mayte; Álvarez, Javier

    2006-01-01

    Producción Científica There is increasing evidence that mitochondria play an important role in the control of cytosolic Ca2+ signaling. We show here that the main mitochondrial Ca2+-exit pathway, the mitochondrial Na+/Ca2+ exchanger, controls the pattern of cytosolic Ca2+ oscillations in nonexcitable cells. In HeLa cells, the inhibitor of the mitochondrial Na+/Ca2+ exchanger CGP37157 changed the pattern of the oscillations induced by histamine from a high-frequency irregular one t...

  18. Pycnogenol protects CA3-CA1 synaptic function in a rat model of traumatic brain injury.

    Science.gov (United States)

    Norris, Christopher M; Sompol, Pradoldej; Roberts, Kelly N; Ansari, Mubeen; Scheff, Stephen W

    2016-02-01

    Pycnogenol (PYC) is a patented mix of bioflavonoids with potent anti-oxidant and anti-inflammatory properties. Previously, we showed that PYC administration to rats within hours after a controlled cortical impact (CCI) injury significantly protects against the loss of several synaptic proteins in the hippocampus. Here, we investigated the effects of PYC on CA3-CA1 synaptic function following CCI. Adult Sprague-Dawley rats received an ipsilateral CCI injury followed 15 min later by intravenous injection of saline vehicle or PYC (10 mg/kg). Hippocampal slices from the injured (ipsilateral) and uninjured (contralateral) hemispheres were prepared at seven and fourteen days post-CCI for electrophysiological analyses of CA3-CA1 synaptic function and induction of long-term depression (LTD). Basal synaptic strength was impaired in slices from the ipsilateral, relative to the contralateral, hemisphere at seven days post-CCI and susceptibility to LTD was enhanced in the ipsilateral hemisphere at both post-injury timepoints. No interhemispheric differences in basal synaptic strength or LTD induction were observed in rats treated with PYC. The results show that PYC preserves synaptic function after CCI and provides further rationale for investigating the use of PYC as a therapeutic in humans suffering from neurotrauma.

  19. Association between interferon gamma 13-CA-repeats polymorphism and metastasis of nasopharyngeal carcinoma in a population of Northern China.

    Science.gov (United States)

    Hao, Kaifei; Yan, Zhaohui; Shuang, Yu; Sun, Jinsong; Tao, Shudong; Fu, Wenyuan; Liu, Lei

    2015-01-01

    Interferon Gamma gamma (IFN-γ) 13-CA-repeats polymorphism is associated with a variety of diseases; here we report its association with nasopharyngeal carcinoma (NPC) metastasis in a retrospective analysis of a cohort of 220 NPC patients in the northern China. The results showed that the distributions of CA13-/CA13-genotypes were significantly higher in the patients with lymph node metastasis (P<0.05) and distant metastasis (P<0.001); there was a significant difference between NPC patients with stage I+II and those with stage III+IV regarding CA13+/CA13-(P<0.001) and CA13-/CA13- genotypes (P<0.001); further analysis showed a more pronounced difference between NPC patients with stage I+II+III and those with stage IV for CA13-/CA13-genotype (P<0.001), whereas no difference was found for CA13+/CA13- genotype (P=0.790). Thus, we identify that IFN-γ 13-CA-repeat polymorphism is significantly associated with the metastasis of NPC, which may provide insights into its prognosis and individualized treatment.

  20. Oxidized CaMKII promotes asthma through the activation of mast cells

    Science.gov (United States)

    Qu, Jingjing; Do, Danh C.; Luczak, Elizabeth; Mitzner, Wayne; Anderson, Mark E.; Gao, Peisong

    2017-01-01

    Oxidation of calmodulin-dependent protein kinase II (ox-CaMKII) by ROS has been associated with asthma. However, the contribution of ox-CaMKII to the development of asthma remains to be fully characterized. Here, we tested the effect of ox-CaMKII on IgE-mediated mast cell activation in an allergen-induced mouse model of asthma using oxidant-resistant CaMKII MMVVδ knockin (MMVVδ) mice. Compared with WT mice, the allergen-challenged MMVVδ mice displayed less airway hyperresponsiveness (AHR) and inflammation. These MMVVδ mice exhibited reduced levels of ROS and diminished recruitment of mast cells to the lungs. OVA-activated bone marrow–derived mast cells (BMMCs) from MMVVδ mice showed a significant inhibition of ROS and ox-CaMKII expression. ROS generation was dependent on intracellular Ca2+ concentration in BMMCs. Importantly, OVA-activated MMVVδ BMMCs had suppressed degranulation, histamine release, leukotriene C4, and IL-13 expression. Adoptive transfer of WT, but not MMVVδ, BMMCs, reversed the alleviated AHR and inflammation in allergen-challenged MMVVδ mice. The CaMKII inhibitor KN-93 significantly suppressed IgE-mediated mast cell activation and asthma. These studies support a critical but previously unrecognized role of ox-CaMKII in mast cells that promotes asthma and suggest that therapies to reduce ox-CaMKII may be a novel approach for asthma. PMID:28097237

  1. The mitochondrial Na+/Ca2+ exchanger upregulates glucose dependent Ca2+ signalling linked to insulin secretion.

    Directory of Open Access Journals (Sweden)

    Iulia I Nita

    Full Text Available Mitochondria mediate dual metabolic and Ca(2+ shuttling activities. While the former is required for Ca(2+ signalling linked to insulin secretion, the role of the latter in β cell function has not been well understood, primarily because the molecular identity of the mitochondrial Ca(2+ transporters were elusive and the selectivity of their inhibitors was questionable. This study focuses on NCLX, the recently discovered mitochondrial Na(+/Ca(2+ exchanger that is linked to Ca(2+ signalling in MIN6 and primary β cells. Suppression either of NCLX expression, using a siRNA construct (siNCLX or of its activity, by a dominant negative construct (dnNCLX, enhanced mitochondrial Ca(2+ influx and blocked efflux induced by glucose or by cell depolarization. In addition, NCLX regulated basal, but not glucose-dependent changes, in metabolic rate, mitochondrial membrane potential and mitochondrial resting Ca(2+. Importantly, NCLX controlled the rate and amplitude of cytosolic Ca(2+ changes induced by depolarization or high glucose, indicating that NCLX is a critical and rate limiting component in the cross talk between mitochondrial and plasma membrane Ca(2+ signalling. Finally, knockdown of NCLX expression was followed by a delay in glucose-dependent insulin secretion. These findings suggest that the mitochondrial Na(+/Ca(2+ exchanger, NCLX, shapes glucose-dependent mitochondrial and cytosolic Ca(2+ signals thereby regulating the temporal pattern of insulin secretion in β cells.

  2. Structural basis for the high Ca2+ affinity of the ubiquitous SERCA2b Ca2+ pump.

    Science.gov (United States)

    Vandecaetsbeek, Ilse; Trekels, Mieke; De Maeyer, Marc; Ceulemans, Hugo; Lescrinier, Eveline; Raeymaekers, Luc; Wuytack, Frank; Vangheluwe, Peter

    2009-11-03

    Sarco(endo)plasmic reticulum Ca(2+) ATPase (SERCA) Ca(2+) transporters pump cytosolic Ca(2+) into the endoplasmic reticulum, maintaining a Ca(2+) gradient that controls vital cell functions ranging from proliferation to death. To meet the physiological demand of the cell, SERCA activity is regulated by adjusting the affinity for Ca(2+) ions. Of all SERCA isoforms, the housekeeping SERCA2b isoform displays the highest Ca(2+) affinity because of a unique C-terminal extension (2b-tail). Here, an extensive structure-function analysis of SERCA2b mutants and SERCA1a2b chimera revealed how the 2b-tail controls Ca(2+) affinity. Its transmembrane (TM) segment (TM11) and luminal extension functionally cooperate and interact with TM7/TM10 and luminal loops of SERCA2b, respectively. This stabilizes the Ca(2+)-bound E1 conformation and alters Ca(2+)-transport kinetics, which provides the rationale for the higher apparent Ca(2+) affinity. Based on our NMR structure of TM11 and guided by mutagenesis results, a structural model was developed for SERCA2b that supports the proposed 2b-tail mechanism and is reminiscent of the interaction between the alpha- and beta-subunits of Na(+),K(+)-ATPase. The 2b-tail interaction site may represent a novel target to increase the Ca(2+) affinity of malfunctioning SERCA2a in the failing heart to improve contractility.

  3. Atrial myocyte function and Ca2+ handling is associated with inborn aerobic capacity.

    Directory of Open Access Journals (Sweden)

    Anne Berit Johnsen

    Full Text Available Although high aerobic capacity is associated with effective cardiac function, the effect of aerobic capacity on atrial function, especially in terms of cellular mechanisms, is not known. We aimed to investigate whether rats with low inborn maximal oxygen uptake (VO2 max had impaired atrial myocyte contractile function when compared to rats with high inborn VO2 max.Atrial myocyte function was depressed in Low Capacity Runners (LCR relative to High Capacity Runners (HCR which was associated with impaired Ca(2+ handling. Fractional shortening was 52% lower at 2 Hz and 60% lower at 5 Hz stimulation while time to 50% relengthening was 43% prolonged and 55% prolonged, respectively. Differences in Ca(2+ amplitude and diastolic Ca(2+ level were observed at 5 Hz stimulation where Ca(2+ amplitude was 70% lower and diastolic Ca(2+ level was 11% higher in LCR rats. Prolonged time to 50% Ca(2+ decay was associated with reduced sarcoplasmic reticulum (SR Ca(2+ ATPase function in LCR (39%. Na(+/Ca(2+ exchanger activity was comparable between the groups. Diastolic SR Ca(2+ leak was increased by 109%. This could be partly explained by increased ryanodine receptors phosphorylation at the Ca(2+-calmodulin-dependent protein kinase-II specific Ser-2814 site in LCR rats. T-tubules were present in 68% of HCR cells whereas only 33% LCR cells had these structures. In HCR, the significantly higher numbers of cells with T-tubules were combined with greater numbers of myocytes where Ca(2+ release in the cell occurred simultaneously in central and peripheral regions, giving rise to faster and more spatial homogenous Ca(2+-signal onset.This data demonstrates that contrasting for low or high aerobic capacity leads to diverse functional and structural remodelling of atrial myocytes, with impaired contractile function in LCR compared to HCR rats.

  4. Muscle-Type Specific Autophosphorylation of CaMKII Isoforms after Paced Contractions

    Science.gov (United States)

    Eilers, Wouter; Gevers, Wouter; van Overbeek, Daniëlle; de Haan, Arnold; Jaspers, Richard T.; Hilbers, Peter A.; van Riel, Natal; Flück, Martin

    2014-01-01

    We explored to what extent isoforms of the regulator of excitation-contraction and excitation-transcription coupling, calcium/calmodulin protein kinase II (CaMKII) contribute to the specificity of myocellular calcium sensing between muscle types and whether concentration transients in its autophosphorylation can be simulated. CaMKII autophosphorylation at Thr287 was assessed in three muscle compartments of the rat after slow or fast motor unit-type stimulation and was compared against a computational model (CaMuZclE) coupling myocellular calcium dynamics with CaMKII Thr287 phosphorylation. Qualitative differences existed between fast- (gastrocnemius medialis) and slow-type muscle (soleus) for the expression pattern of CaMKII isoforms. Phospho-Thr287 content of δA CaMKII, associated with nuclear functions, demonstrated a transient and compartment-specific increase after excitation, which contrasted to the delayed autophosphorylation of the sarcoplasmic reticulum-associated βM CaMKII. In soleus muscle, excitation-induced δA CaMKII autophosphorylation demonstrated frequency dependence (P = 0.02). In the glycolytic compartment of gastrocnemius medialis, CaMKII autophosphorylation after excitation was blunted. In silico assessment emphasized the importance of mitochondrial calcium buffer capacity for excitation-induced CaMKII autophosphorylation but did not predict its isoform specificity. The findings expose that CaMKII autophosphorylation with paced contractions is regulated in an isoform and muscle type-specific fashion and highlight properties emerging for phenotype-specific regulation of CaMKII. PMID:25054156

  5. Muscle-Type Specific Autophosphorylation of CaMKII Isoforms after Paced Contractions

    Directory of Open Access Journals (Sweden)

    Wouter Eilers

    2014-01-01

    Full Text Available We explored to what extent isoforms of the regulator of excitation-contraction and excitation-transcription coupling, calcium/calmodulin protein kinase II (CaMKII contribute to the specificity of myocellular calcium sensing between muscle types and whether concentration transients in its autophosphorylation can be simulated. CaMKII autophosphorylation at Thr287 was assessed in three muscle compartments of the rat after slow or fast motor unit-type stimulation and was compared against a computational model (CaMuZclE coupling myocellular calcium dynamics with CaMKII Thr287 phosphorylation. Qualitative differences existed between fast- (gastrocnemius medialis and slow-type muscle (soleus for the expression pattern of CaMKII isoforms. Phospho-Thr287 content of δA CaMKII, associated with nuclear functions, demonstrated a transient and compartment-specific increase after excitation, which contrasted to the delayed autophosphorylation of the sarcoplasmic reticulum-associated βM CaMKII. In soleus muscle, excitation-induced δA CaMKII autophosphorylation demonstrated frequency dependence (P = 0.02. In the glycolytic compartment of gastrocnemius medialis, CaMKII autophosphorylation after excitation was blunted. In silico assessment emphasized the importance of mitochondrial calcium buffer capacity for excitation-induced CaMKII autophosphorylation but did not predict its isoform specificity. The findings expose that CaMKII autophosphorylation with paced contractions is regulated in an isoform and muscle type-specific fashion and highlight properties emerging for phenotype-specific regulation of CaMKII.

  6. Ca2+ Influx via the Na+/Ca2+ Exchanger Is Enhanced in Malignant Hyperthermia Skeletal Muscle*

    Science.gov (United States)

    Altamirano, Francisco; Eltit, José M.; Robin, Gaëlle; Linares, Nancy; Ding, Xudong; Pessah, Isaac N.; Allen, Paul D.; López, José R.

    2014-01-01

    Malignant hyperthermia (MH) is potentially fatal pharmacogenetic disorder of skeletal muscle caused by intracellular Ca2+ dysregulation. NCX is a bidirectional transporter that effluxes (forward mode) or influxes (reverse mode) Ca2+ depending on cellular activity. Resting intracellular calcium ([Ca2+]r) and sodium ([Na+]r) concentrations are elevated in MH susceptible (MHS) swine and murine muscles compared with their normal (MHN) counterparts, although the contribution of NCX is unclear. Lowering [Na+]e elevates [Ca2+]r in both MHN and MHS swine muscle fibers and it is prevented by removal of extracellular Ca2+ or reduced by t-tubule disruption, in both genotypes. KB-R7943, a nonselective NCX3 blocker, reduced [Ca2+]r in both swine and murine MHN and MHS muscle fibers at rest and decreased the magnitude of the elevation of [Ca2+]r observed in MHS fibers after exposure to halothane. YM-244769, a high affinity reverse mode NCX3 blocker, reduces [Ca2+]r in MHS muscle fibers and decreases the amplitude of [Ca2+]r rise triggered by halothane, but had no effect on [Ca2+]r in MHN muscle. In addition, YM-244769 reduced the peak and area under the curve of the Ca2+ transient elicited by high [K+]e and increased its rate of decay in MHS muscle fibers. siRNA knockdown of NCX3 in MHS myotubes reduced [Ca2+]r and the Ca2+ transient area induced by high [K+]e. These results demonstrate a functional NCX3 in skeletal muscle whose activity is enhanced in MHS. Moreover reverse mode NCX3 contributes to the Ca2+ transients associated with K+-induced depolarization and the halothane-triggered MH episode in MHS muscle fibers. PMID:24847052

  7. Ca2+ influx via the Na+/Ca2+ exchanger is enhanced in malignant hyperthermia skeletal muscle.

    Science.gov (United States)

    Altamirano, Francisco; Eltit, José M; Robin, Gaëlle; Linares, Nancy; Ding, Xudong; Pessah, Isaac N; Allen, Paul D; López, José R

    2014-07-04

    Malignant hyperthermia (MH) is potentially fatal pharmacogenetic disorder of skeletal muscle caused by intracellular Ca(2+) dysregulation. NCX is a bidirectional transporter that effluxes (forward mode) or influxes (reverse mode) Ca(2+) depending on cellular activity. Resting intracellular calcium ([Ca(2+)]r) and sodium ([Na(+)]r) concentrations are elevated in MH susceptible (MHS) swine and murine muscles compared with their normal (MHN) counterparts, although the contribution of NCX is unclear. Lowering [Na(+)]e elevates [Ca(2+)]r in both MHN and MHS swine muscle fibers and it is prevented by removal of extracellular Ca(2+) or reduced by t-tubule disruption, in both genotypes. KB-R7943, a nonselective NCX3 blocker, reduced [Ca(2+)]r in both swine and murine MHN and MHS muscle fibers at rest and decreased the magnitude of the elevation of [Ca(2+)]r observed in MHS fibers after exposure to halothane. YM-244769, a high affinity reverse mode NCX3 blocker, reduces [Ca(2+)]r in MHS muscle fibers and decreases the amplitude of [Ca(2+)]r rise triggered by halothane, but had no effect on [Ca(2+)]r in MHN muscle. In addition, YM-244769 reduced the peak and area under the curve of the Ca(2+) transient elicited by high [K(+)]e and increased its rate of decay in MHS muscle fibers. siRNA knockdown of NCX3 in MHS myotubes reduced [Ca(2+)]r and the Ca(2+) transient area induced by high [K(+)]e. These results demonstrate a functional NCX3 in skeletal muscle whose activity is enhanced in MHS. Moreover reverse mode NCX3 contributes to the Ca(2+) transients associated with K(+)-induced depolarization and the halothane-triggered MH episode in MHS muscle fibers.

  8. Induction of CaSR expression circumvents the molecular features of malignant CaSR null colon cancer cells.

    Science.gov (United States)

    Singh, Navneet; Chakrabarty, Subhas

    2013-11-15

    We recently reported on the isolation and characterization of calcium sensing receptor (CaSR) null human colon cancer cells (Singh et al., Int J Cancer 2013; 132: 1996-2005). CaSR null cells possess a myriad of molecular features that are linked to a highly malignant and drug resistant phenotype of colon cancer. The CaSR null phenotype can be maintained in defined human embryonic stem cell culture medium. We now show that the CaSR null cells can be induced to differentiate in conventional culture medium, regained the expression of CaSR with a concurrent reversal of the cellular and molecular features associated with the null phenotype. These features include cellular morphology, expression of colon cancer stem cell markers, expression of survivin and thymidylate synthase and sensitivity to fluorouracil. Other features include the expression of epithelial mesenchymal transition linked molecules and transcription factors, oncogenic miRNAs and tumor suppressive molecule and miRNA. With the exception of cancer stem cell markers, the reversal of molecular features, upon the induction of CaSR expression, is directly linked to the expression and function of CaSR because blocking CaSR induction by shRNA circumvented such reversal. We further report that methylation and demethylation of the CaSR gene promoter underlie CaSR expression. Due to the malignant nature of the CaSR null cells, inclusion of the CaSR null phenotype in disease management may improve on the mortality of this disease. Because CaSR is a robust promoter of differentiation and mediates its action through diverse mechanisms and pathways, inactivation of CaSR may serve as a new paradigm in colon carcinogenesis.

  9. Foeniculum vulgare Mill. increases cytosolic Ca(2+) concentration and inhibits store-operated Ca(2+) entry in vascular endothelial cells.

    Science.gov (United States)

    Han, A Young; Lee, Hui Su; Seol, Geun Hee

    2016-12-01

    This study assessed the effects of essential oil of Foeniculum vulgare Mill. (fennel oil) and of trans-anethole, the main component of fennel oil, on extracellular Ca(2+)-induced store-operated Ca(2+) entry (SOCE) into vascular endothelial (EA) cells and their mechanisms of action. Components of fennel oil were analyzed by gas chromatography-mass spectrometry. Cytosolic Ca(2+) concentration ([Ca(2+)]c) in EA cells was determined using Fura-2 fluorescence. In the presence of extracellular Ca(2+), fennel oil significantly increased [Ca(2+)]c in EA cells; this increase was significantly inhibited by the Ca(2+) channel blockers La(3+) and nifedipine. In contrast, fennel oil induced [Ca(2+)]c was significantly lower in Ca(2+)-free solution, suggesting that fennel oil increases [Ca(2+)]c mainly by enhancing Ca(2+) influx into EA cells. [Ca(2+)]c mobilization by trans-anethole was similar to that of fennel oil. Moreover, SOCE was suppressed by fennel oil and trans-anethole. SOCE was also attenuated by lanthanum (La(3+)), a non-selective cation channel (NSC) blocker; 2-aminoethoxydiphenyl borane (2-APB), an inositol 1,4,5-triphosphate (IP3) receptor inhibitor and SOCE blocker; and U73122, an inhibitor of phospholipase C (PLC). Further, SOCE was more strongly inhibited by La(3+) plus fennel oil or trans-anethole than by La(3+) alone. These findings suggest that fennel oil and trans-anethole significantly inhibit SOCE-induced [Ca(2+)]c increase in vascular endothelial cells and that these reactions may be mediated by NSC, IP3-dependent Ca(2+) mobilization, and PLC activation.

  10. PGC-1{alpha} accelerates cytosolic Ca{sup 2+} clearance without disturbing Ca{sup 2+} homeostasis in cardiac myocytes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Min, E-mail: chenminyx@gmail.com [Institute of Molecular Medicine, State Key Laboratory of Biomembrane and Membrane Biotechnology, Peking University, Beijing 100871 (China); Yunnan Centers for Diseases Prevention and Control, Kunming 650022 (China); Wang, Yanru [Institute of Molecular Medicine, State Key Laboratory of Biomembrane and Membrane Biotechnology, Peking University, Beijing 100871 (China); Qu, Aijuan [Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 (United States)

    2010-06-11

    Energy metabolism and Ca{sup 2+} handling serve critical roles in cardiac physiology and pathophysiology. Peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1{alpha}) is a multi-functional coactivator that is involved in the regulation of cardiac mitochondrial functional capacity and cellular energy metabolism. However, the regulation of PGC-1{alpha} in cardiac Ca{sup 2+} signaling has not been fully elucidated. To address this issue, we combined confocal line-scan imaging with off-line imaging processing to characterize calcium signaling in cultured adult rat ventricular myocytes expressing PGC-1{alpha} via adenoviral transduction. Our data shows that overexpressing PGC-1{alpha} improved myocyte contractility without increasing the amplitude of Ca{sup 2+} transients, suggesting that myofilament sensitivity to Ca{sup 2+} increased. Interestingly, the decay kinetics of global Ca{sup 2+} transients and Ca{sup 2+} waves accelerated in PGC-1{alpha}-expressing cells, but the decay rate of caffeine-elicited Ca{sup 2+} transients showed no significant change. This suggests that sarcoplasmic reticulum (SR) Ca{sup 2+}-ATPase (SERCA2a), but not Na{sup +}/Ca{sup 2+} exchange (NCX) contribute to PGC-1{alpha}-induced cytosolic Ca{sup 2+} clearance. Furthermore, PGC-1{alpha} induced the expression of SERCA2a in cultured cardiac myocytes. Importantly, overexpressing PGC-1{alpha} did not disturb cardiac Ca{sup 2+} homeostasis, because SR Ca{sup 2+} load and the propensity for Ca{sup 2+} waves remained unchanged. These data suggest that PGC-1{alpha} can ameliorate cardiac Ca{sup 2+} cycling and improve cardiac work output in response to physiological stress. Unraveling the PGC-1{alpha}-calcium handing pathway sheds new light on the role of PGC-1{alpha} in the therapy of cardiac diseases.

  11. Inelastic electron scattering from 48Ca

    Science.gov (United States)

    Wise, J. E.; McCarthy, J. S.; Altemus, R.; Norum, B. E.; Whitney, R. R.; Heisenberg, J.; Dawson, J.; Schwentker, O.

    1985-05-01

    Inelastic electron scattering from 48Ca has been performed over a momentum transfer range from 0.6 to 3.0 fm-1 in both forward and backward directions. Form factors have been obtained for 25 levels up to 10 MeV excitation. Charge and current densities for 11 low lying electric transitions and current densities for two magnetic transitions have been reconstructed in Fourier Bessel analysis. Three high spin states observed in the region of 9 MeV excitation are found to have the dominant configuration ν(1g9/2,1f-17/2)8 - but with a total strength of only 36% predicted for the first 8- in a random-phase-approximation calculation. This is interpreted as evidence for particle-phonon coupling. Comparisons of the extracted densities are made with random-phase-approximation calculations using a zero-range, density-dependent Migdal interaction.

  12. paja de caña

    Directory of Open Access Journals (Sweden)

    David Verdecia Torres

    2005-01-01

    Full Text Available En el presente trabajo se realiza un estudio de la combustión de briquetas cilíndricas macizas de biomasa cañera en particular lo referente a la cinética del proceso de combustión lográndose determinar los tiempos de combustión de cada una de las fases que pudieran ser las controladoras del proceso; la difusión de O2 a través de la película gaseosa, la difusión de los volátiles a través de la capa de ceniza y la reacción química; a partir del modelo del núcleo sin reaccionar

  13. Ca isotope fingerprints of early crust-mantle evolution

    Science.gov (United States)

    Kreissig, K.; Elliott, T.

    2005-01-01

    The utility of 40Ca/ 44Ca as a tracer of pre-existing crustal contributions in early Archaean cratons has been explored to identify traces of Hadean crust and to assess the style of continental growth. The relatively short half-life of 40K (˜1.3 Gy) means that its decay to 40Ca occurs dominantly during early Earth History. If Archaean crust had a significant component derived from a more ancient protolith, as anticipated by "steady state" crustal evolution models, this should be clearly reflected in radiogenic 40Ca/ 44Ca ratios (or positive initial ɛ Ca) in different Archaean cratons. A high precision thermal ionisation technique has been used to analyse the 40Ca/ 44Ca ratios of plagioclase separates and associated whole rocks in ˜3.6 Ga (early Archaean) samples from Zimbabwe and West Greenland. Three out of four tonalite, trondhjemite, granodiorite (TTG) suite samples from Zimbabwe display initial 40Ca/ 44Ca ratios indistinguishable from our measured modern MORB value (i.e., ɛ Ca(3.6) ˜ 0). Greenland samples, however, are very diverse ranging from ɛ Ca(3.7) = 0.1 in mafic pillow lavas and felsic sheets from the Isua supracrustal belt, up to very radiogenic signatures (ɛ Ca(3.7) = 2.9) in both mafic rocks of the Akilia association and felsic TTG from the coastal Amîtsoq gneisses. At face value, these results imply the Zimbabwe crust is juvenile whereas most Greenland samples include an earlier crustal component. Yet the west Greenland craton, as with many Archaean localities, has experienced a complex geological history and the interpretation of age-corrected initial isotope values requires great care. Both felsic and mafic samples from Greenland display ɛ Ca(3.7) so radiogenic that they are not readily explained by crustal growth scenarios. The presence of such radiogenic 40Ca/ 44Ca found in low K/Ca plagioclases requires Ca isotope exchange between plagioclase and whole rock during later metamorphic event(s). In addition the unexpectedly radiogenic Ca

  14. Glutamate-354 of the CP43 polypeptide interacts with the oxygen-evolving Mn4Ca cluster of photosystem II: a preliminary characterization of the Glu354Gln mutant.

    Science.gov (United States)

    Strickler, Melodie A; Hwang, Hong Jin; Burnap, Robert L; Yano, Junko; Walker, Lee M; Service, Rachel J; Britt, R David; Hillier, Warwick; Debus, Richard J

    2008-03-27

    In the recent X-ray crystallographic structural models of photosystem II, Glu354 of the CP43 polypeptide is assigned as a ligand of the O2-evolving Mn4Ca cluster. In this communication, a preliminary characterization of the CP43-Glu354Gln mutant of the cyanobacterium Synechocystis sp. PCC 6803 is presented. The steady-state rate of O2 evolution in the mutant cells is only approximately 20% compared with the wild-type, but the kinetics of O2 release are essentially unchanged and the O2-flash yields show normal period-four oscillations, albeit with lower overall intensity. Purified PSII particles exhibit an essentially normal S2 state multiline electron paramagnetic resonance (EPR) signal, but exhibit a substantially altered S2-minus-S1 Fourier transform infrared (FTIR) difference spectrum. The intensities of the mutant EPR and FTIR difference spectra (above 75% compared with wild-type) are much greater than the O2 signals and suggest that CP43-Glu354Gln PSII reaction centres are heterogeneous, with a minority fraction able to evolve O2 with normal O2 release kinetics and a majority fraction unable to advance beyond the S2 or S3 states. The S2-minus-S1 FTIR difference spectrum of CP43-Glu354Gln PSII particles is altered in both the symmetric and asymmetric carboxylate stretching regions, implying either that CP43-Glu354 is exquisitely sensitive to the increased charge that develops on the Mn4Ca cluster during the S1-->S2 transition or that the CP43-Glu354Gln mutation changes the distribution of Mn(III) and Mn(IV) oxidation states within the Mn4Ca cluster in the S1 and/or S2 states.

  15. Effect of intracellular Ca2+ and action potential duration on L-type Ca2+ channel inactivation and recovery from inactivation in rabbit cardiac myocytes.

    Science.gov (United States)

    Altamirano, Julio; Bers, Donald M

    2007-07-01

    Ca(2+) current (I(Ca)) recovery from inactivation is necessary for normal cardiac excitation-contraction coupling. In normal hearts, increased stimulation frequency increases force, but in heart failure (HF) this force-frequency relationship (FFR) is often flattened or reversed. Although reduced sarcoplasmic reticulum Ca(2+)-ATPase function may be involved, decreased I(Ca) availability may also contribute. Longer action potential duration (APD), slower intracellular Ca(2+) concentration ([Ca(2+)](i)) decline, and higher diastolic [Ca(2+)](i) in HF could all slow I(Ca) recovery from inactivation, thereby decreasing I(Ca) availability. We measured the effect of different diastolic [Ca(2+)](i) on I(Ca) inactivation and recovery from inactivation in rabbit cardiac myocytes. Both I(Ca) and Ba(2+) current (I(Ba)) were measured. I(Ca) decay was accelerated only at high diastolic [Ca(2+)](i) (600 nM). I(Ba) inactivation was slower but insensitive to [Ca(2+)](i). Membrane potential dependence of I(Ca) or I(Ba) availability was not affected by [Ca(2+)](i) <600 nM. Recovery from inactivation was slowed by both depolarization and high [Ca(2+)](i). We also used perforated patch with action potential (AP)-clamp and normal Ca(2+) transients, using various APDs as conditioning pulses for different frequencies (and to simulate HF APD). Recovery of I(Ca) following longer APD was increasingly incomplete, decreasing I(Ca) availability. Trains of long APs caused a larger I(Ca) decrease than short APD at the same frequency. This effect on I(Ca) availability was exacerbated by slowing twitch [Ca(2+)](i) decline by approximately 50%. We conclude that long APD and slower [Ca(2+)](i) decline lead to cumulative inactivation limiting I(Ca) at high heart rates and might contribute to the negative FFR in HF, independent of altered Ca(2+) channel properties.

  16. Transgenic up-regulation of alpha-CaMKII in forebrain leads to increased anxiety-like behaviors and aggression

    Directory of Open Access Journals (Sweden)

    Hasegawa Shunsuke

    2009-03-01

    Full Text Available Abstract Background Previous studies have demonstrated essential roles for alpha-calcium/calmodulin-dependent protein kinase II (alpha-CaMKII in learning, memory and long-term potentiation (LTP. However, previous studies have also shown that alpha-CaMKII (+/- heterozygous knockout mice display a dramatic decrease in anxiety-like and fearful behaviors, and an increase in defensive aggression. These findings indicated that alpha-CaMKII is important not only for learning and memory but also for emotional behaviors. In this study, to understand the roles of alpha-CaMKII in emotional behavior, we generated transgenic mice overexpressing alpha-CaMKII in the forebrain and analyzed their behavioral phenotypes. Results We generated transgenic mice overexpressing alpha-CaMKII in the forebrain under the control of the alpha-CaMKII promoter. In contrast to alpha-CaMKII (+/- heterozygous knockout mice, alpha-CaMKII overexpressing mice display an increase in anxiety-like behaviors in open field, elevated zero maze, light-dark transition and social interaction tests, and a decrease in locomotor activity in their home cages and novel environments; these phenotypes were the opposite to those observed in alpha-CaMKII (+/- heterozygous knockout mice. In addition, similarly with alpha-CaMKII (+/- heterozygous knockout mice, alpha-CaMKII overexpressing mice display an increase in aggression. However, in contrast to the increase in defensive aggression observed in alpha-CaMKII (+/- heterozygous knockout mice, alpha-CaMKII overexpressing mice display an increase in offensive aggression. Conclusion Up-regulation of alpha-CaMKII expression in the forebrain leads to an increase in anxiety-like behaviors and offensive aggression. From the comparisons with previous findings, we suggest that the expression levels of alpha-CaMKII are associated with the state of emotion; the expression level of alpha-CaMKII positively correlates with the anxiety state and strongly affects

  17. Protective effects of kaempferol against cardiac sinus node dysfunction via CaMKII deoxidization.

    Science.gov (United States)

    An, Minae; Kim, Minsuk

    2015-12-01

    Kaempferol exerts cardioprotective actions through incompletely understood mechanisms. This study investigated the molecular mechanisms underlying the cardioprotective effects of kaempferol in sinus node dysfunction (SND) heart. Here, we demonstrate that angiotensin II (Ang II) infusion causes SND through oxidized calmodulin kinase II (CaMKII). In contrast to this, kaempferol protects sinus node against Ang II-induced SND. Ang II evoked apoptosis with caspase-3 activation in sinus nodal cells. However, kaempferol lowered the CaMKII oxidization and the sinus nodal cell death. To block the CaMKII oxidization, gene of p47phox, a cytosolic subunit of NADPH oxidase, was deleted using Cas9 KO plasmid. In the absence of p47phox, sinus nodal cells were highly resistance to Ang II-induced apoptosis, suggesting that oxidized-CaMKII contributed to sinus nodal cell death. In Langendorff heart from Ang II infused mice, kaempferol preserved normal impulse formation at right atrium. These data suggested that kaempferol protects sinus node via inhibition of CaMKII oxidization and may be useful for preventing SND in high risk patients.

  18. Apocalmodulin and Ca2+ calmodulin bind to the same region on the skeletal muscle Ca2+ release channel

    Science.gov (United States)

    Moore, C. P.; Rodney, G.; Zhang, J. Z.; Santacruz-Toloza, L.; Strasburg, G.; Hamilton, S. L.

    1999-01-01

    The skeletal muscle Ca2+ release channel (RYR1) is regulated by calmodulin in both its Ca2+-free (apocalmodulin) and Ca2+-bound (Ca2+ calmodulin) states. Apocalmodulin is an activator of the channel, and Ca2+ calmodulin is an inhibitor of the channel. Both apocalmodulin and Ca2+ calmodulin binding sites on RYR1 are destroyed by a mild tryptic digestion of the sarcoplasmic reticulum membranes, but calmodulin (either form), bound to RYR1 prior to tryptic digestion, protects both the apocalmodulin and Ca2+ calmodulin sites from tryptic destruction. The protected sites are after arginines 3630 and 3637 on RYR1. These studies suggest that both Ca2+ calmodulin and apocalmodulin bind to the same or overlapping regions on RYR1 and block access of trypsin to sites at amino acids 3630 and 3637. This sequence is part of a predicted Ca2+ CaM binding site of amino acids 3614-3642 [Takeshima, H., et al. (1989) Nature 339, 439-445].

  19. Electrodeposition and characterization of CaF{sub 2} and rare earth doped CaF{sub 2} films

    Energy Technology Data Exchange (ETDEWEB)

    Wang Hui; Liu Run, E-mail: runliu@zju.edu.cn; Chen Keli; Shi Xiaofang; Xu Zhude

    2011-07-29

    Calcium fluoride (CaF{sub 2}) and the rare earth doped CaF{sub 2} films have been electrodeposited on indium tin oxide (ITO) electrode through electrochemical generation of acid in aqueous solutions near room temperature. For CaF{sub 2} film electrodeposition, the local pH at ITO surface is lowered by the electrochemical oxidation of ascorbate anion, and then the Ca-ethylene diamine tetraacetic acid disodium complexes which are close to the ITO electrode are decomposed to release free Ca{sup 2+} to react with F{sup -}to form CaF{sub 2} deposit onto ITO. In the same way, RE-doped CaF{sub 2} films have been electrodeposited onto ITO electrode. The morphology of films studied by scanning electron microscopy revealed that they are agglomerated and dense. The films showed a little [111] preferred orientation by X-ray diffraction. It was also proved that doped RE ions were distributed homogeneously in the film by energy dispersive spectroscopy mapping. The optical properties of the electrodeposited CaF{sub 2}, CaF{sub 2}:Eu and CaF{sub 2}:Tb films were studied by photoluminescence, and all films exhibit intense emission peaks.

  20. Peroxisome Ca(2+) homeostasis in animal and plant cells.

    Science.gov (United States)

    Costa, Alex; Drago, Ilaria; Zottini, Michela; Pizzo, Paola; Pozzan, Tullio

    2013-01-01

    Ca(2+) homeostasis in peroxisomes has been an unsolved problem for many years. Recently novel probes to monitor Ca(2+) levels in the lumen of peroxisomes in living cells of both animal and plant cells have been developed. Here we discuss the contrasting results obtained in mammalian cells with chemiluminecsent (aequorin) and fluorescent (cameleon) probes targeted to peroxisomes. We briefly discuss the different characteristics of these probes and the possible pitfalls of the two approaches. We conclude that the contrasting results obtained with the two probes may reflect a heterogeneity among peroxisomes in mammalian cells. We also discuss the results obtained in plant peroxisomes. In particular we demonstrate that Ca(2+) increases in the cytoplasm are mirrored by similar rises of Ca(2+) concentration the lumen of peroxisomes. The increases in peroxisome Ca(2+) level results in the activation of a catalase isoform, CAT3. Other functional roles of peroxisomal Ca(2+) changes in plant physiology are briefly discussed.

  1. A cold metal poor cloud traced by a weak MgII absorption at z~0.45. First detection of SiI, CaI and FeI in a QSO absorber

    CERN Document Server

    D'Odorico, Valentina

    2007-01-01

    We present the observations of a weak MgII absorption system detected at z~0.452 in the UVES high resolution spectrum of the QSO HE0001-2340. The weakest of the two MgII components forming the system shows associated absorptions due to SiI, CaI and FeI observed for the first time in a QSO spectrum. We investigate the nature of this absorber by comparing its properties with those of different classes of absorbers (weak MgII, Damped Ly-alpha systems and local interstellar clouds) and reproducing its ionization conditions with photoionization models. The observed absorber belongs to the class of weak MgII systems on the basis of its equivalent width, however the relative strength of commonly observed transitions deviates significantly from those of the above mentioned absorbers. A rough estimate of the probability to cross such a system with a QSO line of sight is P~0.03. The presence of rare neutral transitions suggests that the cloud is shielded by a large amount of neutral Hydrogen. A detailed comparison of t...

  2. Neuromodulation of the Feedforward Dentate Gyrus-CA3 Microcircuit

    Science.gov (United States)

    Prince, Luke Y.; Bacon, Travis J.; Tigaret, Cezar M.; Mellor, Jack R.

    2016-01-01

    The feedforward dentate gyrus-CA3 microcircuit in the hippocampus is thought to activate ensembles of CA3 pyramidal cells and interneurons to encode and retrieve episodic memories. The creation of these CA3 ensembles depends on neuromodulatory input and synaptic plasticity within this microcircuit. Here we review the mechanisms by which the neuromodulators aceylcholine, noradrenaline, dopamine, and serotonin reconfigure this microcircuit and thereby infer the net effect of these modulators on the processes of episodic memory encoding and retrieval. PMID:27799909

  3. Interactions of vanadate oligomers with sarcoplasmic reticulum Ca(2+)-ATPase.

    Science.gov (United States)

    Aureliano, M; Mdeira, V M

    1994-04-28

    Upon addition of sarcoplasmic reticulum (SR), the line width of tetrameric vanadate signal of 51V-NMR spectra narrowed in the presence of ATP and Ca2+, whereas monomeric vanadate line widths were broadened. Thus, ATP decreases the affinity of the enzyme for tetravanadate whereas it induces the interaction with monomeric vanadate. In the presence of Ca2+ it was observed that tetrameric and decameric vanadate bind to SR ATPase whereas monomeric vanadate only binds to SR when ATP is present. However, decameric vanadate clearly differs from vanadate oligomers present in monovanadate solutions in preventing the accumulation of Ca2+ by sarcoplasmic reticulum (SR) vesicles coupled to ATP hydrolysis. Mg2+ increased the inhibitory effect promoted by decavanadate whereas a slight enhancement of Ca2+ uptake was observed in the presence of monovanadate. For 5 mM Mg2+, a nominal 2 mM vanadium 'decavanadate' solution containing about 190 to 200 microM decameric and less than 100 microM monomeric species depressed the rate of Ca2+ uptake by 50% whereas a nominal 2 mM monovanadate solution containing about 662 microM monomeric, 143 microM dimeric and 252 microM tetrameric species had no effect on the rate of Ca2+ accumulation. However, 2 mM 'decavanadate' inhibits by 75% the SR Ca(2+)-ATPase activity whereas the presence of 2 mM 'monovanadate' produces an inhibitory effect below 50%. Therefore, the Ca:ATP stoichiometry of Ca2+ transport is enhanced by monovanadate. In the presence of oxalate, inhibition of SR Ca(2+)-ATPase activity by these solutions is enhanced to 97% and 86% whereas in the presence of the ionophore lasalocid, the inhibitory values were 87% and 19% for 2 mM decavanadate and 2 mM monovanadate solutions, respectively. Apparently, the increase of vesicular Ca2+ concentration counteracts monovanadate inhibition of SR Ca(2+)-ATPase activity but it does not significantly affect decavanadate inhibition.

  4. SNL/CA Environmental Management System Program Manual.

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, Barbara L.

    2007-04-01

    The Sandia National Laboratories, California (SNL/CA) Environmental Management System (EMS) Program Manual documents the elements of the site EMS Program. The SNL/CA EMS Program conforms to the International Standard on Environmental Management Systems, ISO 14001:2004. Elements of the ISO standard overlap with those of Department of Energy (DOE) Order 450.1, thus SNL/CA's EMS program also meets the DOE requirements.

  5. Neuromodulation of the feedforward dentate gyrus-CA3 microcircuit

    OpenAIRE

    Luke Yuri Prince; Travis J Bacon; Tigaret, Cezar M.; Mellor, Jack R.

    2016-01-01

    The feedforward dentate gyrus-CA3 microcircuit in the hippocampus is thought to activate ensembles of CA3 pyramidal cells and interneurons to encode and retrieve episodic memories. The creation of these CA3 ensembles depends on neuromodulatory input and synaptic plasticity within this microcircuit. Here we review the mechanisms by which the neuromodulators aceylcholine, noradrenaline, dopamine, and serotonin reconfigure this microcircuit and thereby infer the net effect of these modulators on...

  6. Neuromodulation of the Feedforward Dentate Gyrus-CA3 Microcircuit

    OpenAIRE

    Prince, Luke; Travis J Bacon; Tigaret, Cezar; Mellor, Jack

    2016-01-01

    The feedforward dentate gyrus-CA3 microcircuit in the hippocampus is thought to activate ensembles of CA3 pyramidal cells and interneurons to encode and retrieve episodic memories. The creation of these CA3 ensembles depends on neuromodulatory input and synaptic plasticity within this microcircuit. Here we review the mechanisms by which the neuromodulators aceylcholine, noradrenaline, dopamine, and serotonin reconfigure this microcircuit and thereby infer the net effect of these modulators on...

  7. Neuromodulation of the Feedforward Dentate Gyrus-CA3 Microcircuit.

    Science.gov (United States)

    Prince, Luke Y; Bacon, Travis J; Tigaret, Cezar M; Mellor, Jack R

    2016-01-01

    The feedforward dentate gyrus-CA3 microcircuit in the hippocampus is thought to activate ensembles of CA3 pyramidal cells and interneurons to encode and retrieve episodic memories. The creation of these CA3 ensembles depends on neuromodulatory input and synaptic plasticity within this microcircuit. Here we review the mechanisms by which the neuromodulators aceylcholine, noradrenaline, dopamine, and serotonin reconfigure this microcircuit and thereby infer the net effect of these modulators on the processes of episodic memory encoding and retrieval.

  8. Expression of Ca2+-ATPase and Na+/Ca2+-exchanger is upregulated during epithelial Ca2+ transport in hypodermal cells of the isopod Porcellio scaber.

    Science.gov (United States)

    Ziegler, A; Weihrauch, D; Towle, D W; Hagedorn, M

    2002-09-01

    It is thought that a plasma membrane Ca(2+)-transport ATPase (PMCA) and a Na(+)/Ca(2+)-exchange (NCE) mechanism are involved in epithelial Ca(2+) transport (ECT) in a variety of crustacean epithelia. The sternal epithelium of the terrestrial isopod Porcellio scaber was used as a model for the analysis of Ca(2+)-extrusion mechanisms in the hypodermal epithelium. Using RT-PCR, we amplified a cDNA fragment of 1173 bp that encodes a protein sequence possessing 72% identity to the PMCA from Drosophila melanogaster and a cDNA fragment of 791 bp encoding a protein sequence with 50% identity to the NCE from Loligo opalescens. Semiquantitative RT-PCR revealed that the expression of both mRNAs increases from the non-Ca(2+)-transporting condition to the stages of CaCO(3) deposit formation and degradation. During Ca(2+)-transporting stages, the expression of PMCA and NCE was larger in the anterior sternal epithelium (ASE) than in the posterior sternal epithelium (PSE). The results demonstrate for the first time the expression of a PMCA and a NCE in the hypodermal epithelium of a crustacean and indicate a contribution of these transport mechanisms in ECT.

  9. Hypervitaminosis D mediates compensatory Ca2+ hyperabsorption in TRPV5 knockout mice.

    NARCIS (Netherlands)

    Renkema, K.Y.R.; Nijenhuis, T.; Eerden, B.C. van der; Kemp, J.W.C.M. van der; Weinans, H.; Leeuwen, J.P.P.M. van; Bindels, R.J.M.; Hoenderop, J.G.J.

    2005-01-01

    Vitamin D plays an important role in Ca(2+) homeostasis by controlling Ca(2+) (re)absorption in intestine, kidney, and bone. The epithelial Ca(2+) channel TRPV5 mediates the Ca(2+) entry step in active Ca(2+) reabsorption. TRPV5 knockout (TRPV5(-/-)) mice show impaired Ca(2+) reabsorption, hypercalc

  10. The influence of the 2-neutron elastic transfer on the fusion of 42Ca + 40Ca

    Directory of Open Access Journals (Sweden)

    Stefanini A.M.

    2016-01-01

    We have measured the fusion excitation function of this system using the 42Ca beam of the XTU Tandem of LNL on a thin 40Ca target enriched to 99.96% in mass 40. Cross sections have been measured down to ≤1 mb. The extracted barrier distribution shows clearly two main peaks. We have performed preliminary CC calculations where the 2+ coupling strengths have been taken from the literature and the schematic 2n pair transfer form factor has been used, with a deformation length σt= 0.39 fm. The excitation function is well reproduced by the calculation including the 2n transfer channel. However, including the octupole excitations destroys the agreement.

  11. OLM interneurons differentially modulate CA3 and entorhinal inputs to hippocampal CA1 neurons.

    Science.gov (United States)

    Leão, Richardson N; Mikulovic, Sanja; Leão, Katarina E; Munguba, Hermany; Gezelius, Henrik; Enjin, Anders; Patra, Kalicharan; Eriksson, Anders; Loew, Leslie M; Tort, Adriano B L; Kullander, Klas

    2012-11-01

    The vast diversity of GABAergic interneurons is believed to endow hippocampal microcircuits with the required flexibility for memory encoding and retrieval. However, dissection of the functional roles of defined interneuron types has been hampered by the lack of cell-specific tools. We identified a precise molecular marker for a population of hippocampal GABAergic interneurons known as oriens lacunosum-moleculare (OLM) cells. By combining transgenic mice and optogenetic tools, we found that OLM cells are important for gating the information flow in CA1, facilitating the transmission of intrahippocampal information (from CA3) while reducing the influence of extrahippocampal inputs (from the entorhinal cortex). Furthermore, we found that OLM cells were interconnected by gap junctions, received direct cholinergic inputs from subcortical afferents and accounted for the effect of nicotine on synaptic plasticity of the Schaffer collateral pathway. Our results suggest that acetylcholine acting through OLM cells can control the mnemonic processes executed by the hippocampus.

  12. Hippocampal CA3 pyramidal cells selectively innervate aspiny interneurons.

    Science.gov (United States)

    Wittner, Lucia; Henze, Darrell A; Záborszky, László; Buzsáki, György

    2006-09-01

    The specific connectivity among principal cells and interneurons determines the flow of activity in neuronal networks. To elucidate the connections between hippocampal principal cells and various classes of interneurons, CA3 pyramidal cells were intracellularly labelled with biocytin in anaesthetized rats and the three-dimensional distribution of their axon collaterals was reconstructed. The sections were double-stained for substance P receptor (SPR)- or metabotropic glutamate receptor 1alpha (mGluR-1alpha)-immunoreactivity to investigate interneuron targets of the CA3 pyramidal cells. SPR-containing interneurons represent a large portion of the GABAergic population, including spiny and aspiny classes. Axon terminals of CA3 pyramidal cells contacted SPR-positive interneuron dendrites in the hilus and in all hippocampal strata in both CA3 and CA1 regions (7.16% of all boutons). The majority of axons formed single contacts (87.5%), but multiple contacts (up to six) on single target neurons were also found. CA3 pyramidal cell axon collaterals innervated several types of morphologically different aspiny SPR-positive interneurons. In contrast, spiny SPR-interneurons or mGluR-1alpha-positive interneurons in the hilus, CA3 and CA1 regions were rarely contacted by the filled pyramidal cells. These findings indicate a strong target selection of CA3 pyramidal cells favouring the activation of aspiny classes of interneurons.

  13. TRPV5-mediated Ca2+ Reabsorption and Hypercalciuria

    Science.gov (United States)

    Renkema, Kirsten Y.; Hoenderop, Joost G. J.; Bindels, René J. M.

    2007-04-01

    The concerted action of the intestine, kidney and bone results in the maintenance of a normal Ca2+ balance, a mechanism that is tightly controlled by the calciotropic hormones vitamin D, parathyroid hormone and calcitonin. Disturbances in the Ca2+ balance have been linked to diverse pathophysiological disorders like urolithiasis, hypertension, electroencephalogram abnormalities and rickets. Importantly, the final amount of Ca2+ that is released from the body is determined in the distal part of the nephron, where active Ca2+ reabsorption occurs. Here, Transient Receptor Potential Vanilloid member 5 (TRPV5), a highly Ca2+-selective channel, has been recognized as the gatekeeper of active Ca2+ reabsorption. The in vivo relevance of TRPV5 has been further investigated by the characterization of TRPV5 knockout (TRPV5-/-) mice, which exhibit severe disturbances in renal Ca2+ handling, such as profound hypercalciuria, intestinal Ca2+ hyperabsorption and reduced bone thickness. Hypercalciuria increases the risk of kidney stone formation in these mice. This review highlights our current knowledge about TRPV5-mediated Ca2+ reabsorption and emphasizes the physiological relevance and the clinical implications related to the TRPV5-/- mice model.

  14. Differential diagnosis of tuberculosis and lung cancer pleural effusion by CEA, CA125,CA50%CEA、CA125、CA50在结核及肺癌性胸水鉴别中的意义

    Institute of Scientific and Technical Information of China (English)

    冯金栋; 赵卫国; 保鹏涛

    2013-01-01

    Objective:To explore the significance of differential diagnosis of pleural effusion by detection of carci-noembryonic antigen (CEA) ,carbohydrate antigen (CA125) and carbohydrate antigen (CA50). Methods: A total of 126 specimens from pleural effusion diagnosed as TB in 70 cases and lung cancer in 56 cases were collected. CEA, CA125,CA50 in the pleural effusion were analyzed. ResuItS:The expression level and sensitivity of CEA and CA50 in pleural effusion of lung cancer was significantly higher than that in tuberculous (P 0.05). The specificity was only 5.71%. Combining CEA with CA125 to diagnose pleural effusion resulted fom lung cancer, the sensitivity was 92. 11% and combining CA125 with CA50 the sensitivity was 95. 24% . When the concetration of CEA was more than 10ng/ml or the concetration of CA125 was more than 2000U/ml,pleural effusion of lung cancer should be highly suspected. Conclusion;The use of CEA.CA125 and CA50 separately,or in combination is helpful to differential diagnosis of pleural effusion resulted from tuberculosis and lung cancer.%目的:探讨癌胚抗原(CEA)、糖类抗原(CA125)、糖类抗原(CA50)在胸水鉴别诊断中的意义.方法:收集已明确胸水性质的标本126例(结核性70例、癌性56例),检测胸水中CEA、CA125、CA50的数值,进行统计分析.结果:肺癌性胸水中CEA、CA50表达水平及敏感度明显高于结核性胸腔积液(P<0.05),特异性分别为95.71%和98.57%.同样CA125在肺癌性胸水中高表达(P<0.05),但两组敏感度无差异(P>0.05),特异性仅为5.71%;CEA和CA125联合诊断肺癌性胸水的敏感度为92.11%,CA125和CA50联合诊断敏感度为95.24%.CEA> 10ng/ml或CA125> 2000U/ml,可初步定为肺癌性胸水.结论:CEA、CA125、CA50单独或联合检测对鉴别诊断结核及肺癌性胸水有重要临床指导意义.

  15. Energetics of ternary nitrides: Li-Ca-Zn-N and Ca-Ta-N systems

    Energy Technology Data Exchange (ETDEWEB)

    McHale, J.M.; Navrotsky, A. [Princeton Univ., NJ (United States); Kowach, G.R.; Balbarin, V.E.; DiSalvo, F.J. [Cornell Univ., Ithaca, NY (United States)

    1997-07-01

    High-temperature oxide melt drop solution calorimetry was used to study the energetics of ternary nitride formation. The standard enthalpies of formation of several binary and ternary nitrides were determined. These values in kJ mol{sup {minus}1} are {Delta}H{sub f}{degrees}(Li{sub 3}N) = {minus}166.1 {+-} 4.8, {Delta}H{sub f}{degrees}(Ca{sub 3}N{sub 2}) = 439.7{+-} 6.6, {Delta}H{sub f}{degrees}(Zn{sub 3}N{sub 2}) = 43.5 {+-} 4.1, {Delta}H{sub f}{degrees}(Ta{sub 3}N{sub 5}) = 849.7 {+-} 11.7, {Delta}H{sub f}{degrees}(Ca{sub 2}ZnN{sub 2}) = {minus}378.9 {+-} 8.6, {Delta}H{sub f}{degrees}(Sr{sub 2}ZnN{sub 2}) = {minus}385.6 {+-} 14.3, {Delta}H{sub f}{degrees}(LiCaN) = {minus}216.8 {+-} 10.8, {Delta}H{sub f}{degrees}(LiZnN) = {minus}137.5 {+-} 6.8, and {Delta}H{sub f}{degrees}(CaTaN{sub 2}) = 1643.8 {+-} 9.6. These enthalpies of formation are small in magnitude compared to analogous values for oxides. However, the enthalpies of formation of the ternaries from binary nitrides can be quite substantial, confirming significant energetic stabilization of ternary nitrides. The energetics of ternary nitride formation appears to be dominated by the acid/base character of the cations. A linear relationship was found between the enthalpies of formation of the ternaries from binary nitrides and the ionic potential ratio of the two cations. 43 refs., 4 tabs.

  16. Kinetic studies show that Ca2+ and Tb3+ have different binding preferences toward the four Ca2+-binding sites of calmodulin.

    Science.gov (United States)

    Wang, C L; Leavis, P C; Gergely, J

    1984-12-18

    The stepwise addition of Tb3+ to calmodulin yields a large tyrosine-sensitized Tb3+ luminescence enhancement as the third and fourth ions bind to the protein [Wang, C.-L. A., Aquaron, R. R., Leavis, P. C., & Gergely, J. (1982) Eur. J. Biochem. 124, 7-12]. Since the only tyrosine residues in calmodulin are located within binding sites III and IV, these results suggest that Tb3+ binds first to sites I and II. Recent NMR studies have provided evidence that Ca2+, on the other hand, binds preferentially to sites III and IV. Kinetic studies using a stopped-flow apparatus also show that the preferential binding of Ca2+ and lanthanide ions is different. Upon rapid mixing of 2Ca-calmodulin with two Tb3+ ions, there was a small and rapid tyrosine fluorescence change, but no Tb3+ luminescence was observed, indicating that Tb3+ binds to sites I and II but not sites III and IV. When two Tb3+ ions are mixed with 2Dy-calmodulin, Tb3+ luminescence rises rapidly as Tb3+ binds to the empty sites III and IV, followed by a more gradual decrease (k = 0.4 s-1 as the ions redistribute themselves over the four sites. These results indicate that (i) both Tb3+ and Dy3+ prefer binding to sites I and II of calmodulin and (ii) the binding of Tb3+ to calmodulin is not impeded by the presence of two Ca2+ ions initially bound to the protein. Thus, the Ca2+ and lanthanide ions must exhibit opposite preferences for the four sites of calmodulin: sites III and IV are the high-affinity sites for Ca2+, whereas Tb3+ and Dy3+ prefer sites I and II.

  17. Activity-dependent upregulation of presynaptic kainate receptors at immature CA3-CA1 synapses.

    Science.gov (United States)

    Clarke, Vernon R J; Molchanova, Svetlana M; Hirvonen, Teemu; Taira, Tomi; Lauri, Sari E

    2014-12-10

    Presynaptic kainate-type glutamate receptors (KARs) regulate glutamate release probability and short-term plasticity in various areas of the brain. Here we show that long-term depression (LTD) in the area CA1 of neonatal rodent hippocampus is associated with an upregulation of tonic inhibitory KAR activity, which contributes to synaptic depression and causes a pronounced increase in short-term facilitation of transmission. This increased KAR function was mediated by high-affinity receptors and required activation of NMDA receptors, nitric oxide (NO) synthetase, and postsynaptic calcium signaling. In contrast, KAR activity was irreversibly downregulated in response to induction of long-term potentiation in a manner that depended on activation of the TrkB-receptor of BDNF. Both tonic KAR activity and its plasticity were restricted to early stages of synapse development and were lost in parallel with maturation of the network due to ongoing BDNF-TrkB signaling. These data show that presynaptic KARs are targets for activity-dependent modulation via diffusible messengers NO and BDNF, which enhance and depress tonic KAR activity at immature synapses, respectively. The plasticity of presynaptic KARs in the developing network allows nascent synapses to shape their response to incoming activity. In particular, upregulation of KAR function after LTD allows the synapse to preferentially pass high-frequency afferent activity. This can provide a potential rescue from synapse elimination by uncorrelated activity and also increase the computational dynamics of the developing CA3-CA1 circuitry.

  18. Crystal Structure and Dielectric Properties of Microwave Ceramics CaLa(CaM)O6 [M = Nb, Sb

    Science.gov (United States)

    Dutta, Alo; Mandal, Sanjay; Kumari, Premlata; Mukhopadhyay, P. K.; Biswas, S. K.; Sinha, T. P.

    2017-01-01

    The dielectric properties of two perovskite oxides CaLa(CaM)O6 [M = Nb, Sb] synthesized by the solid-state reaction technique have been studied in the microwave and radio frequency range. The phase formation and the crystal structure of the materials are investigated by the Rietveld refinement of the x-ray diffraction data at room temperature. The Raman spectrum substantiates the crystal structure of the materials. The temperature dependence of the relaxation frequencies in the radio frequency range follows the Arrhenius law, and the corresponding activation energies are found to be 0.339 eV and 0.346 eV, respectively, for CaLa(CaNb)O6 and CaLa(CaSb)O6. The difference in the values of the dielectric constant and the loss tangent are correlated with the respective crystal structure of the materials.

  19. Crystal Structure and Dielectric Properties of Microwave Ceramics CaLa(CaM)O6 [M = Nb, Sb

    Science.gov (United States)

    Dutta, Alo; Mandal, Sanjay; Kumari, Premlata; Mukhopadhyay, P. K.; Biswas, S. K.; Sinha, T. P.

    2017-03-01

    The dielectric properties of two perovskite oxides CaLa(CaM)O6 [M = Nb, Sb] synthesized by the solid-state reaction technique have been studied in the microwave and radio frequency range. The phase formation and the crystal structure of the materials are investigated by the Rietveld refinement of the x-ray diffraction data at room temperature. The Raman spectrum substantiates the crystal structure of the materials. The temperature dependence of the relaxation frequencies in the radio frequency range follows the Arrhenius law, and the corresponding activation energies are found to be 0.339 eV and 0.346 eV, respectively, for CaLa(CaNb)O6 and CaLa(CaSb)O6. The difference in the values of the dielectric constant and the loss tangent are correlated with the respective crystal structure of the materials.

  20. Estimation Model for Electrical Conductivity of CaF2-CaO-Al2O3 Slags

    Science.gov (United States)

    Shi, Guan-yong; Zhang, Ting-an; Dou, Zhi-he; Niu, Li-ping

    2016-09-01

    Electrical conductivity is one of the most important properties of molten slags. It has an important influence on process parameter selection of the electroslag remelting process. In the present work, a new model for estimating electrical conductivity of high-temperature slags has been proposed via calculating the conductivity by electrical conductivity of pure substances and interaction parameters between the different components in the slag has been proposed. In this model, the Arrhenius law is used to describe the relationship between electrical conductivity and temperature of slags. This model has been successfully applied to the CaF2-Al2O3, CaF2-CaO, and CaO-Al2O3, as well as CaF2-CaO-Al2O3 systems, and the calculated results are in good agreement with the measured values.

  1. The role of CaMKII in regulating GLUT4 expression in skeletal muscle.

    Science.gov (United States)

    Ojuka, Edward O; Goyaram, Veeraj; Smith, James A H

    2012-08-01

    Contractile activity during physical exercise induces an increase in GLUT4 expression in skeletal muscle, helping to improve glucose transport capacity and insulin sensitivity. An important mechanism by which exercise upregulates GLUT4 is through the activation of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) in response to elevated levels of cytosolic Ca(2+) during muscle contraction. This review discusses the mechanism by which Ca(2+) activates CaMKII, explains research techniques currently used to alter CaMK activity in cells, and highlights various exercise models and pharmacological agents that have been used to provide evidence that CaMKII plays an important role in regulating GLUT4 expression. With regard to transcriptional mechanisms, the key research studies that identified myocyte enhancer factor 2 (MEF2) and GLUT4 enhancer factor as the major transcription factors regulating glut4 gene expression, together with their binding domains, are underlined. Experimental evidence showing that CaMK activation induces hyperacetylation of histones in the vicinity of the MEF2 domain and increases MEF2 binding to its cis element to influence MEF2-dependent Glut4 gene expression are also given along with data suggesting that p300 might be involved in acetylating histones on the Glut4 gene. Finally, an appraisal of the roles of other calcium- and non-calcium-dependent mechanisms, including the major HDAC kinases in GLUT4 expression, is also given.

  2. Dust depletion of Ca and Ti in QSO absorption line systems

    CERN Document Server

    Guber, C R

    2016-01-01

    To explore the role of titanium- and calcium-dust depletion in gas in and around galaxies we systematically study Ti/Ca abundance ratios in intervening absorption-line systems at low and high redshift. We investigate high-resolution optical spectra obtained by the UVES instrument at the Very Large Telescope and spectroscopically analyze 34 absorption-line systems at z<=0.5 to measure column densities (or limits) for CaII and TiII. We complement our UVES data set with previously published absorption-line data on Ti/Ca for redshifts up to z~3.8. Our absorber sample contains 110 absorbers (DLAs, sub-DLAs & LLSs). We compare our Ti/Ca findings with results from the Milky Way and the Magellanic Clouds and discuss the properties of Ti/Ca absorbers in the general context of quasar absorption-line systems.Our analysis indicates that there are two distinct populations of absorbers with either high or low Ti/Ca ratios with a separation at [Ti/Ca}]~1. While the calcium dust depletion in most of the absorbers appe...

  3. Different Levels of CEA, CA153 and CA125 in Milk and Benign and Malignant Nipple Discharge.

    Directory of Open Access Journals (Sweden)

    Song Zhao

    Full Text Available The aim of this study was to assess the diagnostic values of three breast tumor markers (i.e., CEA, CA153 and CA125 in milk and nipple discharge in the prediction of different breast diseases diagnoses.Three hundred thirty-six patients (96 breast cancer and 240 benign disease patients with nipple discharge and a control group of 56 healthy parturient participants were enrolled in the present study. Nipple discharge samples were preoperatively collected from the patients, and milk was collected from the colostrum of the parturient participants. The samples were assayed for the CEA, CA153 and CA125 levels. Cutoff values were determined for the detection of breast diseases using ROC curves.The levels of CEA, CA153 and CA125 were significantly different between the nipple discharge and the milk (all ps < 0.001. In the nipple discharge, the CEA and CA153 levels in the breast cancer group were significantly greater than those in the benign group (all ps < 0.001, and cutoff values of 263.3 ng/mL and 1235.3 U/mL, respectively, were established. However, the expression of CA125 did not differ significantly between the breast cancer and benign groups.Differences in the apparent expression levels of CEA, CA153 and CA125 in patients with nipple discharge and healthy persons were validated. The present data suggest that CEA and CA153 might potentially be useful in the differential diagnoses of benign tumors and breast cancer. CA125 did not seem to be useful for breast cancer detection.

  4. Model-based asessment of an in-vivo predictive relationship from CA1 to CA3 in the rodent hippocampus.

    Science.gov (United States)

    Sandler, Roman A; Song, Dong; Hampson, Robert E; Deadwyler, Sam A; Berger, Theodore W; Marmarelis, Vasilis Z

    2015-02-01

    Although an anatomical connection from CA1 to CA3 via the Entorhinal Cortex (EC) and through backprojecting interneurons has long been known it exist, it has never been examined quantitatively on the single neuron level, in the in-vivo nonpatholgical, nonperturbed brain. Here, single spike activity was recorded using a multi-electrode array from the CA3 and CA1 areas of the rodent hippocampus (N = 7) during a behavioral task. The predictive power from CA3→CA1 and CA1→CA3 was examined by constructing Multivariate Autoregressive (MVAR) models from recorded neurons in both directions. All nonsignificant inputs and models were identified and removed by means of Monte Carlo simulation methods. It was found that 121/166 (73 %) CA3→CA1 models and 96/145 (66 %) CA1→CA3 models had significant predictive power, thus confirming a predictive 'Granger' causal relationship from CA1 to CA3. This relationship is thought to be caused by a combination of truly causal connections such as the CA1→EC→CA3 pathway and common inputs such as those from the Septum. All MVAR models were then examined in the frequency domain and it was found that CA3 kernels had significantly more power in the theta and beta range than those of CA1, confirming CA3's role as an endogenous hippocampal pacemaker.

  5. Improving a natural CaMKII inhibitor by random and rational design.

    Directory of Open Access Journals (Sweden)

    Steven J Coultrap

    Full Text Available BACKGROUND: CaM-KIIN has evolved to inhibit stimulated and autonomous activity of the Ca(2+/calmodulin (CaM-dependent protein kinase II (CaMKII efficiently, selectively, and potently (IC50 ∼100 nM. The CN class of peptides, derived from the inhibitory region of CaM-KIIN, provides powerful new tools to study CaMKII functions. The goal of this study was to identify the residues required for CaMKII inhibition, and to assess if artificial mutations could further improve the potency achieved during evolution. METHODOLOGY/PRINCIPAL FINDINGS: First, the minimal region with full inhibitory potency was identified (CN19 by determining the effect of truncated peptides on CaMKII activity in biochemical assays. Then, individual residues of CN19 were mutated. Most individual Ala substitutions decreased potency of CaMKII inhibition, however, P3A, K13A, and R14A increased potency. Importantly, this initial Ala scan suggested a specific interaction of the region around R11 with the CaMKII substrate binding site, which was exploited for further rational mutagenesis to generate an optimized pseudo-substrate sequence. Indeed, the potency of the optimized peptide CN19o was >250fold improved (IC50 <0.4 nM, and CN19o has characteristics of a tight-binding inhibitor. The selectivity for CaMKII versus CaMKI was similarly improved (to almost 100,000fold for CN19o. A phospho-mimetic S12D mutation decreased potency, indicating potential for regulation by cellular signaling. Consistent with importance of this residue in inhibition, most other S12 mutations also significantly decreased potency, however, mutation to V or Q did not. CONLUSIONS/SIGNIFICANCE: These results provide improved research tools for studying CaMKII function, and indicate that evolution fine-tuned CaM-KIIN not for maximal potency of CaMKII inhibition, but for lower potency that may be optimal for dynamic regulation of signal transduction.

  6. VizieR Online Data Catalog: Interstellar Ca I absorption (Welty+, 2003)

    Science.gov (United States)

    Welty, D. E.; Hobbs, L. M.; Morton, D. C.

    2003-07-01

    We present high-resolution (FWHM~0.3-1.5km/s) spectra, obtained with the AAT UHRF, the McDonald Observatory 2.7m coude spectrograph, and/or the KPNO coude feed, of interstellar Ca I absorption toward 30 Galactic stars. Comparisons of the column densities of Ca I, Ca II, K I, and other species - for individual components identified in the line profiles and also when integrated over entire lines of sight - yield information on relative electron densities and depletions (dependent on assumptions regarding the ionization equilibrium). (2 data files).

  7. CATHODIC BEHAVIORS OF CAO IN MOLTEN SALTS CaCl2 AND EQUIMOLAR CaCl2-X(X=NaCl,BaCl2,LiCl)%CaO在CaCl2和等摩尔CaCl2-X(X=NaCl,BaCl2,LiCl)熔盐中的阴极行为

    Institute of Scientific and Technical Information of China (English)

    王淑兰; 王伟; 王川华; 张丽君

    2008-01-01

    采用循环伏安方法研究了1173 K时CaCl2-0.5%CaO(摩尔分数)和等摩尔CaCl2-X-0.5%CaO(X=NaCl,BaCl2,LiCl)熔盐中CaO在Mo电极上的阴极行为.研究结果表明,CaCl2与CaO电离的Ca计具有不同的离子结构和还原电势,在1173 K时其还原峰电势分别为-2.15和-1.51 V.等摩尔混合熔盐CaCl2-x-0.5%CaO(x=NaCl,BaCl2)中,CaO诱发电解质产生低电位沉积,降低了混合熔盐的电化学稳定性.通过阴极扫描电流峰密度与扫描速率的关系,计算出1173 K时CaO电离的Ca2+在CaCl2-0.5%CaO,等摩尔的CaCl2-NaCl-0.5%CaO,CaCl2-BaCl2-0.5%CaO和CaCl2-LiCl-0.5%CaO熔盐中的扩散系数,分别为6.42×10-5,1.56×10-5,1.20×10-5和6.79×10-5 cm2/s.

  8. Effects of Ca2+/CaM Messenger System Inhibitors on Ethylene-Induced Increase in Lycopene Content

    Institute of Scientific and Technical Information of China (English)

    GU Cai-qin; XI Yu-fang; GUAN Jun-feng; LI Guang-min

    2003-01-01

    The changes of lycopene content during ripening and senescence of tomato fruit and the relationship between ethylene glycol-bis (EGTA, Ca2+ chelator), verapamil (Vp, Ca2+ channel blockers), trifluoperazine (TFP), chloropromaize (CPZ) (CaM antagonism) and ethylene-induced increase in lycopene content in tomato fruit were investigated. Lycopene content accumulated obviously during ripening and senescence of tomato fruit after harvest at pink stage. Low temperature inhibited but ethylene enhanced the lycopene content.Meanwhile, ethylene also promoted calmodulin (CaM) content in tomato fruit, which was related to the concentration of ethylene. When EGTA, Vp, TFP and CPZ with ethylene were used to treat tomato fruit, ethylene-induced increase in lycopene content could be reversed, indicating that blocking Ca2+ channel in plasma membrane or chelating extracellular Ca2+ or inhibiting the activity of CaM could decrease the action of ethylene, and suggesting that Ca2+-CaM messenger system may be involved in lycopene increase inducedby ethylene.

  9. Thapsigargin, a tumor promoter, discharges intracellular Ca2+ stores by specific inhibition of the endoplasmic reticulum Ca2(+)-ATPase

    DEFF Research Database (Denmark)

    Thastrup, Ole; Cullen, P J; Drøbak, B K

    1990-01-01

    Thapsigargin, a tumor-promoting sesquiterpene lactone, discharges intracellular Ca2+ in rat hepatocytes, as it does in many vertebrate cell types. It appears to act intracellularly, as incubation of isolated rat liver microsomes with thapsigargin induces a rapid, dose-dependent release of stored Ca....... This hypothesis is strongly supported by the demonstration that thapsigargin causes a rapid inhibition of the Ca2(+)-activated ATPase activity of rat liver microsomes, with an identical dose dependence to that seen in whole cell or isolated microsome Ca2+ discharge. The inhibition of the endoplasmic reticulum...

  10. GABA application to hippocampal CA3 or CA1 stratum lacunosum-moleculare excites an interneuron network.

    Science.gov (United States)

    Perkins, Katherine L

    2002-03-01

    Whole cell voltage-clamp recording and focal application of the neurotransmitter gamma-aminobutyric acid (GABA) were used to investigate the ability of exogenous GABA applied to different locations within the guinea pig hippocampal slice to trigger a giant GABA-mediated postsynaptic current (GPSC) in pyramidal cells. A GPSC reflects the synchronous release of GABA from a group of interneurons. Recordings were done in the presence of 4-aminopyridine (4-AP) and blockers of ionotropic glutamatergic synaptic transmission. Spontaneous GPSCs occurred rhythmically in pyramidal cells under these conditions. Brief focal pressure application of GABA (500 microM; 30-200 ms) to CA3 stratum lacunosum-moleculare (SLM) or to the border between CA3 s. radiatum (SR) and SLM triggered an "all-or-none" GPSC in CA3 and CA1 pyramidal cells that looked like the spontaneous GPSCs. During the refractory period following a spontaneous GPSC, application of GABA could not trigger a GPSC. Both spontaneous GPSCs and GPSCs triggered by exogenous GABA were blocked by suppressing synaptic transmission with high Mg(2+)/low Ca(2+) bath solution. On the other hand, focal application of GABA to CA3 s. oriens (SO) or to proximal SR did not trigger a GPSC in the CA3 pyramidal cell; instead it produced a graded response. Focal application of GABA to regions other than CA3 was also tested. Focal application of GABA to CA1 SLM always triggered a GPSC in the CA3 pyramidal cell. Focal application of GABA within the outer two-thirds of the dentate molecular layer often elicited a GPSC in the CA3 pyramidal cell. In contrast, focal application of GABA to CA1 SO, to CA1 SR, or to the hilus elicited no current response in the CA3 pyramidal cell. These data indicate that the GPSC recorded in pyramidal cells that was triggered by focal GABA application resulted from the synchronous synaptic release of GABA from activated interneurons rather than from the binding of exogenous GABA to receptors on the pyramidal cell

  11. Spacial compartmentalization of Ca2+ signaling complexes in pancreatic acini.

    Science.gov (United States)

    Xu, X; Zeng, W; Diaz, J; Muallem, S

    1996-10-04

    Imaging [Ca2+]i at high temporal resolution and measuring the properties of Ca2+ signaling in streptolysin O (SLO)-permeabilized cells were used to study the spacial organization of signaling complexes. Sequential stimulation of single cells within pancreatic acini with several Ca2+-mobilizing agonists revealed an agonist-specific pattern and propagation rate of Ca2+ waves in the same cells, with CCK8 stimulating the fastest and bombesin the slowest waves. More importantly, each agonist initiated the wave in a different region of the same cell. On the other hand, repetitive stimulation with the same agonist induced Ca2+ waves of the same pattern that were initiated from the same region of the cell. The agonist-specific Ca2+ signaling does not appear to be the result of coupling to different G proteins as infusion of an anti-Galphaq antibody into the cells through a patch pipette equally inhibited Ca2+ signaling by all agonists. Further evidence for compartmentalization of signaling complexes was developed in permeabilized cells. The time-dependent loss of Ca2+ signaling due to SLO permeabilization occurred in an agonist-specific manner in the sequence cabachol > bombesin > cholecystokinin. Signaling by all agonists could be completely restored with as low as 2 micro guanosine 5'-3-O-(thio)triphosphate (GTPgammaS). At this low concentration GTPgammaS recoupled inositol 1,4,5-trisphosphate production and Ca2+ release, rather than enhancing phospholipase C activity. Priming of Ca2+ signaling by GTPgammaS was agonist-specific. Guanosine 5'-O-(thio)diphosphate (GDPbetaS) uncoupled the ability of signaling complexes to release Ca2+ much better than stimulating inositol 1,4,5-trisphosphate production. The uncoupling of Ca2+ signaling by GDPbetaS was also agonist-specific. The combined findings of agonist-specific initiation sites of the Ca2+ wave and differential access of guanine nucleotides to signaling complexes suggest spacial compartmentalization of Ca2+ signaling

  12. Tracing Ca K grains through the chromosphere into the transition region

    Science.gov (United States)

    Steffens, S.; Deubner, F.-L.; Fleck, B.; Wilhelm, K.

    1997-01-01

    The propagation of Ca K grains from the lower chromosphere into the transition region is studied. Data from the solar ultraviolet measurement of emitted radiation (SUMER) and the VTT at Inzana (Tenerife) instruments were used. The purpose of the study was to investigate the formation of shock waves in the chromosphere. The most dynamical features in the chromosphere defined by the bright Ca II K emission in the filtergrams and spectrograms were analyzed.

  13. Dehydration transformation in Ca-montmorillonite

    Indian Academy of Sciences (India)

    P Bala; B K Samantaray; S K Srivastava

    2000-02-01

    The present work deals with the dehydration transformation of Ca-montmorillonite in the temperature range 30°–500°C. Thermal, infrared (IR), and X-ray diffraction (XRD) analyses were used to describe the thermal transformation. The microstructural and layer disorder parameters like crystallite size, r.m.s. strain ($\\langle e^2\\rangle^{1/2}$), variation of interlayer spacing (), and proportion of planes which were affected by the defect (), have all been calculated from the (001) basal reflection using the method of variance and Fourier line shape analysis. These investigations revealed that sample underwent transformation from hydrated phase to dehydrated phase at 200°C, and as a consequence, its basal spacing collapsed from 16.02 Å (30°C) to around 10 Å (200°C). This transformation occurred through a wide range of temperature, i.e. within the range 120°–200°C. The crystallite size was maximum at room temperature (30°C), however, the size decreased with increasing temperature in the hydrated phase, whereas the size increased with increasing temperature for the dehydrated phase. The , and $\\langle e^2\\rangle^{1/2}$ of the hydrated and the dehydrated phase increased and decreased, respectively with increase of heating temperature.

  14. RESEM-CA: Validation and testing

    Energy Technology Data Exchange (ETDEWEB)

    Pal, Vineeta; Carroll, William L.; Bourassa, Norman

    2002-09-01

    This report documents the results of an extended comparison of RESEM-CA energy and economic performance predictions with the recognized benchmark tool DOE2.1E to determine the validity and effectiveness of this tool for retrofit design and analysis. The analysis was a two part comparison of patterns of (1) monthly and annual energy consumption of a simple base-case building and controlled variations in it to explore the predictions of load components of each program, and (2) a simplified life-cycle cost analysis of the predicted effects of selected Energy Conservation Measures (ECMs). The study tries to analyze and/or explain the differences that were observed. On the whole, this validation study indicates that RESEM is a promising tool for retrofit analysis. As a result of this study some factors (incident solar radiation, outside air film coefficient, IR radiation) have been identified where there is a possibility of algorithmic improvements. These would have to be made in a way that does not sacrifice the speed of the tool, necessary for extensive parametric search of optimum ECM measures.

  15. On SA, CA, and GA numbers

    CERN Document Server

    Caveney, Geoffrey; Sondow, Jonathan

    2011-01-01

    Gronwall's function $G$ is defined for $n>1$ by $G(n)=\\frac{\\sigma(n)}{n \\log\\log n}$ where $\\sigma(n)$ is the sum of the divisors of $n$. We call an integer $N>1$ a \\emph{GA1 number} if $N$ is composite and $G(N) \\ge G(N/p)$ for all prime factors $p$ of $N$. We say that $N$ is a \\emph{GA2 number} if $G(N) \\ge G(aN)$ for all multiples $aN$ of $N$. In arXiv 1110.5078, we used Robin's and Gronwall's theorems on $G$ to prove that the Riemann Hypothesis (RH) is true if and only if 4 is the only number that is both GA1 and GA2. Here, we study GA1 numbers and GA2 numbers separately. We compare them with superabundant (SA) and colossally abundant (CA) numbers (first studied by Ramanujan). We give algorithms for computing GA1 numbers; the smallest one with more than two prime factors is 183783600, while the smallest odd one is 1058462574572984015114271643676625. We find nineteen GA2 numbers $\\le 5040$, and prove that a GA2 number $N>5040$ exists if and only if RH is false, in which case $N$ is even and $>10^{8576}$.

  16. Interactive effects of organic fertilizer,CaSO4 and amino acid Ca on Fuji apple in Burozem soil in China

    Institute of Scientific and Technical Information of China (English)

    ZHENG Weiwei; CHEN Feng; XU Yuehua; ZHANG Jing; ZHAI Heng

    2007-01-01

    A two-year trial was conducted to test the interactive effects of special-for-apple organic fertilizer,CaSO4,and amino acid Ca on Fuji/Balenghaitang (Malus robusta Rehd.) rootstock in Burozem soil in China.Total Ca,exchangeable Ca,and fruit Ca were significantly improved by the soil application of CaSO4 with the highest exchangeable Ca and fruit Ca observed in Fuji apple trees treated at the rate of 3.5 kg CaSO4 per tree.3.5 kg CaSO4 was divided into two applications,with first application in the first month after full bloom,and the second in the second month after full bloom in summer,progressively to improve fruit Ca concentration.Dividing CaSO4 into two applications in combination with organic fertilizer or amino acid Ca spray,proved to be more effective on improving the fruit Ca concentration,with the highest level of 179.17 mg/kg FW in Fuji apple trees treated with 2 kg CaSO4 applied and amino acid Ca sprayed in the first month after full bloom,1.5 kg CaSO4 applied in summer,organic fertilizer applied in winter.Organic fertilizer applied in winter alone remarkably improved the fruit Ca concentration,as well as storage Ca in roots and stems,and the best effect was observed in Fuji apple trees which were supplemented organic fertilizer (10 kg) in winter and CaSO4 (1 kg)in the first month after full bloom per tree.The effect on Ca increment became less pronounced when the amount of organic fertilizer reached 15 kg or CaSO4 was more than 3.5 kg per tree.There was a positive correlation between the Ca/Mg ratio in soil and fruit,exchangeable Ca,and fruit Ca concentration,while a negative correlation was observed between the N/Ca ratio in fruit,available P,available K in soil,and fruit Ca concentration.Both N/Ca ratio and Ca/Mg ratio in fruit were affected by different fertilization regime,and bitter pit incidence at the end of storage kept acceptable only if N/Ca<17 and Ca/Mg≥7 at harvest.The commercial fertilization regime turned out to be organic fertilizer in

  17. Effect of phosphate, silicate, and Ca on the morphology, structure and elemental composition of Fe(III)-precipitates formed in aerated Fe(II) and As(III) containing water

    Science.gov (United States)

    Kaegi, Ralf; Voegelin, Andreas; Folini, Doris; Hug, Stephan J.

    2010-10-01

    We investigated Fe(III)-precipitates formed from Fe(II) oxidation in water at pH 7 as a function of dissolved Fe(II), As(III), phosphate, and silicate in the absence and presence of Ca. We used transmission electron microscopy (TEM), including selected area electron diffraction (SAED) and energy dispersive X-ray spectroscopy (EDX) to characterize the morphology, structure and elemental composition of the precipitates. Results from our companion X-ray absorption spectroscopy (XAS) study suggested that the oxidation of Fe(II) leads to the sequential formation of distinct polymeric units in the following order: Fe(III)-phosphate oligomers in the presence of phosphate, silicate-rich hydrous ferric oxide (HFO-Si) at high Si/Fe (>0.5) or 2-line ferrihydrite (2L-Fh) at lower Si/Fe (˜0.1-0.5), and lepidocrocite (Lp) in the absence of phosphate at low Si/Fe (arrangement of the different polymeric units within Fe(III)-precipitates. The resulting structural and compositional heterogeneity of short-range-ordered Fe(III)-precipitates likely affects their colloidal stability and their chemical reactivity and needs to be considered when addressing the fate of co-transformed trace elements such as arsenic.

  18. ISORROPIA II: a computationally efficient thermodynamic equilibrium model for K+─Ca²+─Mg²+─NH4+─Na+─SO4²-─NO3-─Cl-─H2O aerosols

    Directory of Open Access Journals (Sweden)

    C. Fountoukis

    2007-09-01

    Full Text Available This study presents ISORROPIA II, a thermodynamic equilibrium model for the K+–Ca2+–Mg2+–NH4+–Na+–SO42−–NO3−–Cl−–H2O aerosol system. A comprehensive evaluation of its performance is conducted against water uptake measurements for laboratory aerosol and predictions of the SCAPE2 thermodynamic module over a wide range of atmospherically relevant conditions. The two models agree well, to within 13% for aerosol water content and total PM mass, 16% for aerosol nitrate and 6% for aerosol chloride and ammonium. Largest discrepancies were found under conditions of low RH, primarily from differences in the treatment of water uptake and solid state composition. In terms of computational speed, ISORROPIA II was more than an order of magnitude faster than SCAPE2, with robust and rapid convergence under all conditions. The addition of crustal species does not slow down the thermodynamic calculations (compared to the older ISORROPIA code because of optimizations in the activity coefficient calculation algorithm. Based on its computational rigor and performance, ISORROPIA II appears to be a highly attractive alternative for use in large scale air quality and atmospheric transport models.

  19. Application value discussion of CEA, CA19-9, CA242, CA72-4 in early diagnosis of rectal cancer%CEA、CA19-9、CA242、CA72-4在直肠癌早期诊断的应用价值探讨

    Institute of Scientific and Technical Information of China (English)

    周永玲

    2015-01-01

    目的:探讨联合检测癌胚抗原(CEA)、糖类抗原19-9(Carbohydrate antigen 19-9,CA19-9)、糖类抗原242(carbohydrate antigen 242,CA242)、糖类抗原72-4(Carbohydrate antigen 72-4,CA72-4)对直肠癌早期诊断价值。方法采用化学发光法联合检测直肠癌组、直肠良性病变组和健康对照组血清中 CEA、CA19-9、CA242、CA72-4浓度,并进行统计学分析。结果直肠癌组患者血清中 CEA、CA19-9、CA242、CA72-4的含量均明显高于直肠良性病变组及健康对照组,差异有统计学意义(P<0.05),直肠良性病变组和健康对照组比较差异无统计学意义,直肠癌组患者血清四项标志物联合检测的阳性率:72.587%(45/62)高于 CEA 单项检测的阳性率61.29%(38/62)。结论联合检测血清中 CEA、CA19-9、CA242、CA72-4含量可有显著的互补性效提高直肠癌的诊断诊断率,是早期筛查直肠癌一中简单,有效的方法。%Objective To investigate early diagnosis value of CEA, CA19-9, CA242, CA72-4 for rectal cancer. Methods applying chemiluminescence combined with testing serum concentrations of CEA,CA19-9,CA242,CA72-4 of rectal cancer, rectal benign lesion, health control group, and carry on statistical analyis. Result CEA, CA19-9, CA242 and CA72-4 contents in serum of rectal cancer groups were significantly higher than rectal benign lesion and healthy control group, and difference shows statistical significance(P<0.05). Comparison between rectal benign lesion and healthy control group shows no statistical significance. And positive rate of combination test for four markers in serum of rectal cancer group was 72.587% (45/62), which was higher than 61.29% (38/62) of CEA test only. Conclusion combination test for CEA, CA19-9, CA242 and CA72-4 contents can significantly improve diagnostic rate of rectal cancer, which is a simple and effective method for early screening of rectal cancer.

  20. Seawater nutrient and carbonate ion concentrations recorded as P/Ca, Ba/Ca, and U/Ca in the deep-sea coral Desmophyllum dianthus

    Science.gov (United States)

    Anagnostou, Eleni; Sherrell, Robert M.; Gagnon, Alex; LaVigne, Michele; Field, M. Paul; McDonough, William F.

    2011-05-01

    As paleoceanographic archives, deep sea coral skeletons offer the potential for high temporal resolution and precise absolute dating, but have not been fully investigated for geochemical reconstructions of past ocean conditions. Here we assess the utility of skeletal P/Ca, Ba/Ca and U/Ca in the deep sea coral D. dianthus as proxies of dissolved phosphate (remineralized at shallow depths), dissolved barium (trace element with silicate-type distribution) and carbonate ion concentrations, respectively. Measurements of these proxies in globally distributed D. dianthus specimens show clear dependence on corresponding seawater properties. Linear regression fits of mean coral Element/Ca ratios against seawater properties yield the equations: P/Ca coral (μmol/mol) = (0.6 ± 0.1) P/Ca sw(μmol/mol) - (23 ± 18), R2 = 0.6, n = 16 and Ba/Ca coral(μmol/mol) = (1.4 ± 0.3) Ba/Ca sw(μmol/mol) + (0 ± 2), R2 = 0.6, n = 17; no significant relationship is observed between the residuals of each regression and seawater temperature, salinity, pressure, pH or carbonate ion concentrations, suggesting that these variables were not significant secondary dependencies of these proxies. Four D. dianthus specimens growing at locations with Ωarag ⩽ 0.6 displayed markedly depleted P/Ca compared to the regression based on the remaining samples, a behavior attributed to an undersaturation effect. These corals were excluded from the calibration. Coral U/Ca correlates with seawater carbonate ion: U/Ca coral(μmol/mol) = (-0.016 ± 0.003) [CO32-] (μmol/kg) + (3.2 ± 0.3), R2 = 0.6, n = 17. The residuals of the U/Ca calibration are not significantly related to temperature, salinity, or pressure. Scatter about the linear calibration lines is attributed to imperfect spatial-temporal matches between the selected globally distributed specimens and available water column chemical data, and potentially to unresolved additional effects. The uncertainties of these initial proxy calibration regressions

  1. Unanimous Model for Describing the Fast Bioluminescence Kinetics of Ca

    NARCIS (Netherlands)

    Eremeeva, Elena V.; Bartsev, Sergey I.; Berkel, van Willem J.H.; Vysotski, Eugene S.

    2017-01-01

    Upon binding their metal ion cofactors, Ca2+-regulated photoproteins display a rapid increase of light signal, which reaches its peak within milliseconds. In the present study, we investigate bioluminescence kinetics of the entire photoprotein family. All five recombinant hydromedusan Ca2+-regulated

  2. 33 CFR 80.1144 - Bodega and Tomales Bay, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Bodega and Tomales Bay, CA. 80... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1144 Bodega and Tomales Bay, CA. (a... of Bodega Harbor North Breakwater to Bodega Harbor Entrance Light 1....

  3. EST Table: CA945997 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available 1085995|ref|XP_972340.1| PREDICTED: similar to S12e ribosomal protein [Tribolium castaneum] CA945997 L9 ... ...CA945997 KI000033 11/12/09 GO hit GO:0003735(structural constituent of ribosome)|GO

  4. EST Table: CA946075 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available CA946075 KI000114 10/09/28 39 %/193 aa ref|XP_969395.1| PREDICTED: similar to conserved hypothetica...l protein [Tribolium castaneum] gb|EFA00804.1| hypothetical protein TcasGA2_TC003691 [Tribolium ca...: similar to conserved hypothetical protein [Tribolium castaneum] FS915960 L9 ...

  5. EST Table: CA946015 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available 34 %/127 aa gi|189237239|ref|XP_971090.2| PREDICTED: similar to sentrin/sumo-specific protease senp7 [Tribolium castaneum] CA946015 L9 ... ...CA946015 KI000054 11/12/09 n.h 10/09/28 33 %/142 aa ref|XP_002427379.1| sentrin/sum

  6. Influence of pairing in double beta decay of48Ca

    Indian Academy of Sciences (India)

    Prianka Roy; Shashi K Dhiman

    2010-03-01

    Two-neutrino decay matrix elements and half-life of 48Ca are calculated after including neutron–proton pairing correlations in projected Hartree–Fock–Bogoliubov (PHFB) formalism. The GT matrix elements in 2 decay are reduced due to broader smearing of Fermi surfaces. Half-life results for 2 decay of 48Ca with np pairing are better than without pairing.

  7. SNL/CA Environmental Management System Program Manual.

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, Barbara L.

    2005-09-01

    The Sandia National Laboratories, California (SNL/CA) Environmental Management System (EMS) Program Manual documents the elements of the site EMS Program. The SNL/CA EMS Program was developed in accordance with Department of Energy (DOE) Order 450.1 and incorporates the elements of the International Standard on Environmental Management Systems, ISO 14001.

  8. 76 FR 13017 - Environmental Impact Statement: Los Angeles County, CA

    Science.gov (United States)

    2011-03-09

    ... Federal Highway Administration Environmental Impact Statement: Los Angeles County, CA AGENCY: Federal... Environmental Impact Statement will be prepared for a proposed highway project in Los Angeles County, California...), 2241 N. Eastern Ave., Los Angeles, CA 90032. Pasadena--Lake Avenue Church, (4th floor above Harris...

  9. {sup 41}Ca measurements at the Zurich AMS facility

    Energy Technology Data Exchange (ETDEWEB)

    Schnabel, C.; Gartenmann, P.; Suter, M. [Eidgenoessische Technische Hochschule, Zurich (Switzerland); Synal, H.A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Gloris, M.; Leya, I.; Michel, R. [Hannover Univ. (Germany); Herpers, U. [Koeln Univ. (Germany)

    1997-09-01

    Proton-induced production cross sections for {sup 41}Ca from Fe and Ni determined using 6 MV tandem accelerator are presented. The calibration of two secondary standard materials to a standard material of {sup 41}Ca concentration determined by PTB (Braunschweig, Germany) has been carried out. (author) 2 figs., 3 refs.

  10. 33 CFR 80.1118 - Marina Del Rey, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Marina Del Rey, CA. 80.1118 Section 80.1118 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1118 Marina Del Rey, CA. (a) A line drawn from Marina Del Rey Breakwater South Light...

  11. Hierarchic stochastic modelling applied to intracellular Ca(2+ signals.

    Directory of Open Access Journals (Sweden)

    Gregor Moenke

    Full Text Available Important biological processes like cell signalling and gene expression have noisy components and are very complex at the same time. Mathematical analysis of such systems has often been limited to the study of isolated subsystems, or approximations are used that are difficult to justify. Here we extend a recently published method (Thurley and Falcke, PNAS 2011 which is formulated in observable system configurations instead of molecular transitions. This reduces the number of system states by several orders of magnitude and avoids fitting of kinetic parameters. The method is applied to Ca(2+ signalling. Ca(2+ is a ubiquitous second messenger transmitting information by stochastic sequences of concentration spikes, which arise by coupling of subcellular Ca(2+ release events (puffs. We derive analytical expressions for a mechanistic Ca(2+ model, based on recent data from live cell imaging, and calculate Ca(2+ spike statistics in dependence on cellular parameters like stimulus strength or number of Ca(2+ channels. The new approach substantiates a generic Ca(2+ model, which is a very convenient way to simulate Ca(2+ spike sequences with correct spiking statistics.

  12. Crystal Structure of the Vanadate-Inhibited Ca2+-ATPase

    DEFF Research Database (Denmark)

    Clausen, Johannes D.; Bublitz, Maike; Arnou, Bertrand Jean-Paul;

    2016-01-01

    Vanadate is the hallmark inhibitor of the P-type ATPase family; however, structural details of its inhibitory mechanism have remained unresolved. We have determined the crystal structure of sarcoplasmic reticulum Ca2+-ATPase with bound vanadate in the absence of Ca2+. Vanadate is bound...

  13. 33 CFR 80.1134 - Monterey Harbor, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Monterey Harbor, CA. 80.1134 Section 80.1134 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1134 Monterey Harbor, CA. A line drawn...

  14. 33 CFR 80.1110 - Dana Point Harbor, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Dana Point Harbor, CA. 80.1110 Section 80.1110 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1110 Dana Point Harbor, CA. A line drawn...

  15. 33 CFR 80.1136 - Moss Landing Harbor, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Moss Landing Harbor, CA. 80.1136 Section 80.1136 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1136 Moss Landing Harbor, CA. A line drawn...

  16. 33 CFR 80.1148 - Noyo River, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Noyo River, CA. 80.1148 Section 80.1148 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1148 Noyo River, CA. A line drawn from...

  17. 33 CFR 80.1152 - Crescent City Harbor, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Crescent City Harbor, CA. 80.1152 Section 80.1152 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1152 Crescent City Harbor, CA. A line...

  18. 33 CFR 80.1132 - Estero-Morro Bay, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Estero-Morro Bay, CA. 80.1132 Section 80.1132 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1132 Estero-Morro Bay, CA. A line drawn...

  19. 33 CFR 80.1102 - Santa Catalina Island, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Santa Catalina Island, CA. 80.1102 Section 80.1102 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1102 Santa Catalina Island, CA....

  20. 46 CFR 7.115 - Santa Catalina Island, CA.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Santa Catalina Island, CA. 7.115 Section 7.115 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY PROCEDURES APPLICABLE TO THE PUBLIC BOUNDARY LINES Pacific Coast § 7.115 Santa Catalina Island, CA. (a) A line drawn from the northernmost point of Lion Head...

  1. 33 CFR 80.1138 - Santa Cruz Harbor, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Santa Cruz Harbor, CA. 80.1138 Section 80.1138 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1138 Santa Cruz Harbor, CA. A line drawn...

  2. 33 CFR 80.1146 - Albion River, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Albion River, CA. 80.1146 Section 80.1146 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1146 Albion River, CA. A line drawn on an...

  3. 33 CFR 80.1116 - Redondo Harbor, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Redondo Harbor, CA. 80.1116 Section 80.1116 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1116 Redondo Harbor, CA. A line drawn...

  4. 33 CFR 80.1142 - San Francisco Harbor, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false San Francisco Harbor, CA. 80.1142 Section 80.1142 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1142 San Francisco Harbor, CA. A straight...

  5. 33 CFR 80.1108 - Oceanside Harbor, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Oceanside Harbor, CA. 80.1108 Section 80.1108 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1108 Oceanside Harbor, CA. A line drawn...

  6. 33 CFR 80.1126 - Santa Barbara Harbor, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Santa Barbara Harbor, CA. 80.1126 Section 80.1126 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1126 Santa Barbara Harbor, CA. A line...

  7. 33 CFR 80.1112 - Newport Bay, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Newport Bay, CA. 80.1112 Section 80.1112 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1112 Newport Bay, CA. A line drawn from...

  8. 33 CFR 80.1106 - Mission Bay, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Mission Bay, CA. 80.1106 Section 80.1106 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1106 Mission Bay, CA. A line drawn from...

  9. 33 CFR 80.1140 - Pillar Point Harbor, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Pillar Point Harbor, CA. 80.1140 Section 80.1140 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1140 Pillar Point Harbor, CA. A line drawn...

  10. 33 CFR 80.1104 - San Diego Harbor, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false San Diego Harbor, CA. 80.1104 Section 80.1104 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1104 San Diego Harbor, CA. A line drawn...

  11. 33 CFR 80.1130 - San Luis Obispo Bay, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false San Luis Obispo Bay, CA. 80.1130 Section 80.1130 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1130 San Luis Obispo Bay, CA. A line drawn...

  12. 33 CFR 80.1124 - Ventura Marina, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Ventura Marina, CA. 80.1124 Section 80.1124 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1124 Ventura Marina, CA. A line drawn...

  13. 33 CFR 80.1120 - Port Hueneme, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Port Hueneme, CA. 80.1120 Section 80.1120 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1120 Port Hueneme, CA. (a) A line drawn...

  14. 33 CFR 80.1150 - Arcata-Humboldt Bay, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Arcata-Humboldt Bay, CA. 80.1150 Section 80.1150 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1150 Arcata-Humboldt Bay, CA. A line drawn...

  15. Integrated Coastal Management in the Province Ca Mau - Vietnam

    NARCIS (Netherlands)

    Stoop, B.; Bouziotas, D.; Hanssen, J.L.J.; Dunnewolt, J.; Postma, M.G.

    2015-01-01

    The province of Ca Mau is the southernmost part of Vietnam and the Mekong Delta. The water system of Ca Mau faces multiple challenges, both in its coastal zone and in its inland regions. the coastal zone in the province. In view of this, this study presents an integrated approach for combined coasta

  16. Structure and properties of the slags of continuous converting of copper nickel-containing mattes and concentrates: II. Effect of the SiO2/CaO ratio on the structure and liquidus temperature of the slags

    Science.gov (United States)

    Pigarev, S. P.; Tsymbulov, L. B.; Selivanov, E. N.; Chumarev, V. M.

    2012-03-01

    The structure and liquidus temperature of the SiO2-CaO-Al2O3-FeO x -Cu2O-NiO slags that form during continuous converting of copper mattes and concentrates into blister copper are analyzed. The slag melt compositions are varied over a wide SiO2/CaO range. The slags are studied by X-ray diffraction, scanning electron microscopy, and electron-probe microanalysis. The liquidus temperature of the slags is determined by differential thermal analysis. It is found that, depending on the SiO2/CaO ratio, the structure and liquidus temperature of the slags change and the forms of copper in a slag also change. The SiO2/CaO range in a slag is recommended for the process of continuous converting of a copper nickel-containing sulfide raw materials.

  17. Model-Based Assessment of an In-Vivo Predictive Relationship from CA1 to CA3 in the Rodent Hippocampus

    OpenAIRE

    Sandler, Roman A.; Song, Dong; Hampson, Robert E.; Deadwyler, Sam A.; Berger, Theodore W; Marmarelis, Vasilis Z.

    2014-01-01

    Although an anatomical connection from CA1 to CA3 via the Entorhinal Cortex (EC) and through backprojecting interneurons has long been known it exist, it has never been examined quantitatively on the single neuron level, in the in-vivo nonpatholgical, nonperturbed brain. Here, single spike activity was recorded using a multi-electrode array from the CA3 and CA1 areas of the rodent hippocampus (N=7) during a behavioral task. The predictive power from CA3→CA1 and CA1→CA3 was examined by constru...

  18. CaCl2对KAlSi3O8-CaSO4-CaCO3反应体系的影响研究%THE INFLUENCE OF CaCl2 AGENT ADDITION ON THE KAlSi3O8-CaSO4-CaCO3 SYSTEM

    Institute of Scientific and Technical Information of China (English)

    石林; 曾小平; 罗汉金

    2010-01-01

    通过CaCl2添加剂对KAlSi3O8-CaSO4-CaCO3体系研究反应温度和反应时间的影响研究,结果表明:随着CaCl2加入量的增多,体系的反应温度下降,反应时间缩短,当CaCl2的加入量为10%时,反应温度可降至1 000℃,反应时问降至25 min,此时KAlSi3O8的转化率仍可高达83.24%.研究CaCl2的加入对KAlSi3O8-CaSO4-CaCO3反应体系动力学过程的影响,得出反应体系符合金斯特林格动力学方程:FK(G)=1-2/3G-(1-G) 2/3=KKt,反应受扩散过程控制,计算出当CaCl2的加入量为10%时,体系的表观活化能可从原来的128.921 kJ/mol下降至58.320 kJ/mol.

  19. Quantifying Ca2+ release and inactivation of Ca2+ release in fast- and slow-twitch muscles.

    Science.gov (United States)

    Barclay, C J

    2012-12-01

    The aims of this study were to quantify the Ca(2+) release underlying twitch contractions of mammalian fast- and slow-twitch muscle and to comprehensively describe the transient inactivation of Ca(2+) release following a stimulus. Experiments were performed using bundles of fibres from mouse extensor digitorum longus (EDL) and soleus muscles. Ca(2+) release was quantified from the amount of ATP used to remove Ca(2+) from the myoplasm following stimulation. ATP turnover by crossbridges was blocked pharmacologically (N-benzyl-p-toluenesulphonamide for EDL, blebbistatin for soleus) and muscle heat production was used as an index of Ca(2+) pump ATP turnover. At 20°C, Ca(2+) release in response to a single stimulus was 34 and 84 μmol (kg muscle)(-1) for soleus and EDL, respectively, and increased with temperature (30°C: soleus, 61 μmol kg(-1); EDL, 168 μmol kg(-1)). Delivery of another stimulus within 100 ms of the first produced a smaller Ca(2+) release. The maximum magnitude of the decrease in Ca(2+) release was greater in EDL than soleus. Ca(2+) release recovered with an exponential time course which was faster in EDL (mean time constant at 20°C, 32.1 ms) than soleus (65.6 ms) and faster at 30°C than at 20°C. The amounts of Ca(2+) released and crossbridge cycles performed are consistent with a scheme in which Ca(2+) binding to troponin-C allowed an average of ∼1.7 crossbridge cycles in the two muscles.

  20. Spin decomposition of the responses of sup 44 Ca and sup 48 Ca to 300 MeV protons

    Energy Technology Data Exchange (ETDEWEB)

    Baker, F.T.; Bimbot, L.; Fergerson, R.W.; Glashausser, C.; Green, A.; Haeusser, O.; Hicks, K.; Jones, K.; Miller, C.A.; Vetterli, M.; Abegg, R.; Beatty, D.; Bonin, B.; Castel, B.; Chen, X.Y.; Cupps, V.; Djalali, C.; Henderson, R.; Jackson, K.P.; Jeppesen, R.; Nakayama, K.; Nanda, S.K.; Sawafta, R.; Yen, S. (University of Georgia, Athens, Georgia 30602 (US) Institut de Physique Nucleaire, F-91406 Orsay, France Rutgers University, Piscataway, New Jersey 08854 Simon Fraser University, Burnaby, Canada V5A1S6 TRIUMF, 4004 Westbrook Mall, Vancouver, Canada V6T2A3 Los Alamos National Laboratory, Los Alamos, New Mexico 87544 Centre d' Etudes Nucleaires de Saclay, 91191 Gif sur Yvette, CEDEX, France Queen' s University, Kingston, Canada K7L3N6 University of Colorado, Boulder, Colorado 80309 University of South Carolina, Columbia, South Carolina 29208 Continuous Electron Beam Accelerator Facility, 12000 Jefferson Ave., Newport News, Virginia 23606 University of Alberta, Edmonton, Canada T6G2J1)

    1991-07-01

    Angular distributions of the double-differential cross section {ital d}{sup 2}{sigma}/{ital d}{Omega} {ital dE}({sigma}) and the spin-flip probability {ital S}{sub {ital n}{ital n}} have been measured for inclusive proton inelastic scattering from {sup 44}Ca at 290 MeV and from {sup 48}Ca at 318 MeV. Excitation energies up to about 50 MeV for {sup 44}Ca and 40 MeV for {sup 48}Ca have been investigated over the laboratory angular ranges of 3{degree} to 12{degree} for {sup 44}Ca and 3{degree} to 9{degree} for {sup 48}Ca. Multipole decompositions of angular distributions of both the spin-flip cross section {sigma}{ital S}{sub {ital n}{ital n}} and the estimated cross section for {Delta}{ital S}=0 transitions have been performed. Distributions of strengths were deduced for {Delta}{ital L}=1, {Delta}{ital S}=0 (the giant dipole), {Delta}{ital L}=2, {Delta}{ital S}=0 (the giant quadrupole), {Delta}{ital L}=0, {Delta}{ital S}=1 (the magnetic dipole), {Delta}{ital L}=1, {Delta}{ital S}=1 (the spin dipole), and {Delta}{ital L}=2, {Delta}{ital S}=1 (the spin quadrupole). The {Delta}{ital S}=0 summed strengths for {sup 44}Ca are lower than for {sup 40}Ca and {sup 48}Ca. The spin-dipole summed strengths are found to be approximately independent of {ital A}. For {sup 48}Ca, essentially all {ital M}1 strength observed was in the 10.23 MeV 1{sup +} state; for {sup 44}Ca, {ital M}1 strength was observed to be fragmented over a range of 7 to 18 Mev.