87 research outputs found
STIM1, an essential and conserved component of store-operated Ca2+ channel function
Store-operated Ca2+ (SOC) channels regulate many cellular processes, but the underlying molecular components are not well defined. Using an RNA interference (RNAi)-based screen to identify genes that alter thapsigargin (TG)-dependent Ca2+ entry, we discovered a required and conserved role of Stim in SOC influx. RNAi-mediated knockdown of Stim in Drosophila S2 cells significantly reduced TG-dependent Ca2+ entry. Patch-clamp recording revealed nearly complete suppression of the Drosophila Ca2+ release-activated Ca2+ (CRAC) current that has biophysical characteristics similar to CRAC current in human T cells. Similarly, knockdown of the human homologue STIM1 significantly reduced CRAC channel activity in Jurkat T cells. RNAi-mediated knockdown of STIM1 inhibited TG- or agonist-dependent Ca2+ entry in HEK293 or SH-SY5Y cells. Conversely, overexpression of STIM1 in HEK293 cells modestly enhanced TG-induced Ca2+ entry. We propose that STIM1, a ubiquitously expressed protein that is conserved from Drosophila to mammalian cells, plays an essential role in SOC influx and may be a common component of SOC and CRAC channels
Quantum Tunneling in Nuclear Fusion
Recent theoretical advances in the study of heavy ion fusion reactions below
the Coulomb barrier are reviewed. Particular emphasis is given to new ways of
analyzing data, such as studying barrier distributions; new approaches to
channel coupling, such as the path integral and Green function formalisms; and
alternative methods to describe nuclear structure effects, such as those using
the Interacting Boson Model. The roles of nucleon transfer, asymmetry effects,
higher-order couplings, and shape-phase transitions are elucidated. The current
status of the fusion of unstable nuclei and very massive systems are briefly
discussed.Comment: To appear in the January 1998 issue of Reviews of Modern Physics. 13
Figures (postscript file for Figure 6 is not available; a hard copy can be
requested from the authors). Full text and figures are also available at
http://nucth.physics.wisc.edu/preprints
Experimental Search for Solar Axions via Coherent Primakoff Conversion in a Germanium Spectrometer
Results are reported of an experimental search for the unique, rapidly
varying temporal pattern of solar axions coherently converting into photons via
the Primakoff effect in a single crystal germanium detector. This conversion is
predicted when axions are incident at a Bragg angle with a crystalline plane.
The analysis of approximately 1.94 kg.yr of data from the 1 kg DEMOS detector
in Sierra Grande, Argentina, yields a new laboratory bound on axion-photon
coupling of GeV, independent of
axion mass up to ~ 1 keV.Comment: RevTeX, 11 pages, figures can be obtained by fax from
[email protected]. Submitted to Phys. Lett.
A Glial Variant of the Vesicular Monoamine Transporter Is Required To Store Histamine in the Drosophila Visual System
Unlike other monoamine neurotransmitters, the mechanism by which the brain's histamine content is regulated remains unclear. In mammals, vesicular monoamine transporters (VMATs) are expressed exclusively in neurons and mediate the storage of histamine and other monoamines. We have studied the visual system of Drosophila melanogaster in which histamine is the primary neurotransmitter released from photoreceptor cells. We report here that a novel mRNA splice variant of Drosophila VMAT (DVMAT-B) is expressed not in neurons but rather in a small subset of glia in the lamina of the fly's optic lobe. Histamine contents are reduced by mutation of dVMAT, but can be partially restored by specifically expressing DVMAT-B in glia. Our results suggest a novel role for a monoamine transporter in glia that may be relevant to histamine homeostasis in other systems
Gallium Solar Neutrino Experiments: Absorption Cross sections, Neutrino spectra, and Predicted Event Rates
Neutrino absorption cross sections for 71Ga are calculated for all solar
neutrino sources with standard energy spectra, and for laboratory sources of
51Cr and 37Ar; the calculations include, where appropriate, the thermal energy
of fusing solar ions and use improved nuclear and atomic data. The ratio, R, of
measured (in GALLEX and SAGE) to calculated 51Cr capture rate is R = 0.95 +/-
0.07 (exp)} + ^{+0.04}_{-0.03} (theory). Cross sections are also calculated for
specific neutrino energies chosen so that a spline fit determines accurately
the event rates in a gallium detector even if new physics changes the energy
spectrum of solar neutrinos. Theoretical uncertainties are estimated for cross
sections at specific energies and for standard neutrino energy spectra.
Standard energy spectra are presented for pp and CNO neutrino sources in the
appendices. Neutrino fluxes predicted by standard solar models, corrected for
diffusion, have been in the range 120 SNU to 141 SNU since 1968.Comment: 57 pages, ReVTeX file. Accepted for publication in Phys. Rev. C.
Viewgraphs and numerical tables of neutrino spectra and cross sections at
http://www.sns.ias.edu/~jn
Influence of sorbitol on mechanical and physico-chemical properties of soy protein-based bioplastics processed by injection molding
Monitoring conterminous United States (CONUS) land cover change with Web-Enabled Landsat Data (WELD)
26th Annual Computational Neuroscience Meeting (CNS*2017): Part 3 - Meeting Abstracts - Antwerp, Belgium. 15â20 July 2017
This work was produced as part of the activities of FAPESP Research,\ud
Disseminations and Innovation Center for Neuromathematics (grant\ud
2013/07699-0, S. Paulo Research Foundation). NLK is supported by a\ud
FAPESP postdoctoral fellowship (grant 2016/03855-5). ACR is partially\ud
supported by a CNPq fellowship (grant 306251/2014-0)
Modelling human choices: MADeM and decisionâmaking
Research supported by FAPESP 2015/50122-0 and DFG-GRTK 1740/2. RP and AR are also part of the Research, Innovation and Dissemination Center for Neuromathematics FAPESP grant (2013/07699-0). RP is supported by a FAPESP scholarship (2013/25667-8). ACR is partially supported by a CNPq fellowship (grant 306251/2014-0)
- âŠ