3,014 research outputs found
Identification of the role of C/EBP in neurite regeneration following microarray analysis of a L. stagnalis CNS injury model
<p>Abstract</p> <p>Background</p> <p>Neuronal regeneration in the adult mammalian central nervous system (CNS) is severely compromised due to the presence of extrinsic inhibitory signals and a reduced intrinsic regenerative capacity. In contrast, the CNS of adult <it>Lymnaea stagnalis (L. stagnalis)</it>, a freshwater pond snail, is capable of spontaneous regeneration following neuronal injury. Thus, <it>L. stagnalis </it>has served as an animal model to study the cellular mechanisms underlying neuronal regeneration. However, the usage of this model has been limited due to insufficient molecular tools. We have recently conducted a partial neuronal transcriptome sequencing project and reported over 10,000 EST sequences which allowed us to develop and perform a large-scale high throughput microarray analysis.</p> <p>Results</p> <p>To identify genes that are involved in the robust regenerative capacity observed in <it>L. stagnalis</it>, we designed the first gene chip covering ~15, 000 <it>L. stagnalis </it>CNS EST sequences. We conducted microarray analysis to compare the gene expression profiles of sham-operated (control) and crush-operated (regenerative model) central ganglia of adult <it>L. stagnalis</it>. The expression levels of 348 genes were found to be significantly altered (p < 0.05) following nerve injury. From this pool, 67 sequences showed a greater than 2-fold change: 42 of which were up-regulated and 25 down-regulated. Our qPCR analysis confirmed that CCAAT enhancer binding protein (C/EBP) was up-regulated following nerve injury in a time-dependent manner. In order to test the role of C/EBP in regeneration, C/EBP siRNA was applied following axotomy of cultured <it>Lymnaea </it>PeA neurons. Knockdown of C/EBP following axotomy prevented extension of the distal, proximal and intact neurites. <it>In vivo </it>knockdown of C/EBP postponed recovery of locomotory activity following nerve crush. Taken together, our data suggest both somatic and local effects of C/EBP are involved in neuronal regeneration.</p> <p>Conclusions</p> <p>This is the first high-throughput microarray study in <it>L. stagnalis</it>, a model of axonal regeneration following CNS injury. We reported that 348 genes were regulated following central nerve injury in adult <it>L. stagnalis </it>and provided the first evidence for the involvement of local C/EBP in neuronal regeneration. Our study demonstrates the usefulness of the large-scale gene profiling approach in this invertebrate model to study the molecular mechanisms underlying the intrinsic regenerative capacity of adult CNS neurons.</p
Is the late near-infrared bump in short-hard GRB 130603B due to the Li-Paczynski kilonova?
Short-hard gamma-ray bursts (GRBs) are widely believed to be produced by the
merger of two binary compact objects, specifically by two neutron stars or by a
neutron star orbiting a black hole. According to the Li-Paczynski kilonova
model, the merger would launch sub-relativistic ejecta and a
near-infrared/optical transient would then occur, lasting up to days, which is
powered by the radioactive decay of heavy elements synthesized in the ejecta.
The detection of a late bump using the {\em Hubble Space Telescope} ({\em HST})
in the near-infrared afterglow light curve of the short-hard GRB 130603B is
indeed consistent with such a model. However, as shown in this Letter, the
limited {\em HST} near-infrared lightcurve behavior can also be interpreted as
the synchrotron radiation of the external shock driven by a wide mildly
relativistic outflow. In such a scenario, the radio emission is expected to
peak with a flux of Jy, which is detectable for current radio
arrays. Hence, the radio afterglow data can provide complementary evidence on
the nature of the bump in GRB 130603B. It is worth noting that good
spectroscopy during the bump phase in short-hard bursts can test validity of
either model above, analogous to spectroscopy of broad-lined Type Ic supernova
in long-soft GRBs.Comment: 4 pages, 2 figures, published in ApJ Lette
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Bayesian Functional Data Clustering for Temporal Microarray Data
We propose a Bayesian procedure to cluster temporal gene expression microarray profiles,
based on a mixed-effect smoothing-spline model, and design a Gibbs sampler to sample from
the desired posterior distribution. Our method can determine the cluster number automatically
based on the Bayesian information criterion, and handle missing data easily. When applied
to a microarray dataset on the budding yeast, our clustering algorithm provides biologically
meaningful gene clusters according to a functional enrichment analysis
Synergetic Effect of Yihuo Qingyi Decoction () and Recombinant Staphylokinase in Treatment of Severe Acute Pancreatitis of Rats
ObjectiveTo investigate the effect of recombinant staphylokinase (r-Sak) and the Chinese medicine Yihuo Qingyi Decoction (Herbal decoction for severe acute pancreatitis) in the treatment of the severe acute pancreatitis (SAP) in rats, and to observe the synergistic effect of the two.MethodsOne hundred and sixty-two adult male SD rats with the body mass of 250–280 g were randomly divided into the following 5 groups: sham operation group (n=18), control group (n=36), Yihuo Qingyi Decoction treatment group (n=36), r-Sak treatment group (n=36), and Yihuo Qingyi Decoction plus r-Sak treatment group (n=36). The SAP ratmodel was prepared by retrograde injection of 5% sodium taurocholate into the cholangiopancreatic duct. Two days before modeling, Yihuo Qingyi Decoction was intragastrically administrated, and r-Sak was intraperitoneally injected. The survival rate within 18 h after modeling was determined. The pancreatic blood flow, the weight of ascites, and the serum amylase and lipase were investigated at 6 h, 12 h, and 18kh after modeling, and the pancreatic tissue was examined under light microscopy to see its pathological change.ResultsThe 18 h survival count of group A,B,C,D and E rats was 9,2,6,7 and 8 respectively. After r-Sak and Yihuo Qingyi Decoction intervention, the serum amylase and lipase and the weight of ascites were significantly decreased, especially in group E.18 h after modeling, the level of the serum amylase and lipase and the weight of ascites in group E was 1 100±118 U·L−1,1 000±150 U·L−1 and 13.40±1.80 g respectively, obviously lower than that of group B (P<0.05). After SAP was induced, the pancreatic blood flow showed a tendency to decrease, but the decrease extent in the treatment groups was smaller than that in the control group.18h after modeling, the pancreatic blood flow in group B and group E was 30.16±8.96 mL·100 g−1·min−1, and 129.10±42.58 mL·100 g−1·min−1 respectively, there was significant difference (P<0.05). The pathological change of the pancreatic tissue was alleviated in the treatment groups.ConclusionBoth r-Sak and Yihuo Qingyi Decoction play a beneficial role in the treatment of rat SAP and there is a synergistic effect between the two
The N-Terminal Extension of Cardiac Troponin I Regulates the Kinetics of Myosin ATPase Cycle
A supra-massive magnetar central engine for short GRB 130603B
We show that the peculiar early optical and in particular X-ray afterglow
emission of the short duration burst GRB 130603B can be explained by continuous
energy injection into the blastwave from a supra-massive magnetar central
engine. The observed energetics and temporal/spectral properties of the late
infrared bump (i.e., the "kilonova") are also found consistent with emission
from the ejecta launched during an NS-NS merger and powered by a magnetar
central engine. The isotropic-equivalent kinetic energies of both the GRB
blastwave and the kilonova are about erg, consistent
with being powered by a near-isotropic magnetar wind. However, this relatively
small value demands that most of the initial rotational energy of the magnetar
is carried away by gravitational wave
radiation. Our results suggest that (i) the progenitor of GRB 130603B would be
a NS-NS binary system, whose merger product would be a supra-massive neutron
star that lasted for about seconds; (ii) the equation-of-state of
nuclear matter would be stiff enough to allow survival of a long-lived
supra-massive neutron star, so that it is promising to detect bright
electromagnetic counterparts of gravitational wave triggers without short GRB
associations in the upcoming Advanced LIGO/Virgo era.Comment: Five pages including 1 Figure, to appear in ApJ
2-(1,3-Dibenzylimidazolidin-2-ylidene)malononitrile
In the title molecule, C20H18N4, the imidazolidine ring makes dihedral angles of 86.74 (2) and 81.18 (3)° with the two phenyl rings. In the absence of classical intermolecular interactions, the crystal packing is stabilized by van der Waals forces
Comparison of three magnetization transfer ratio parameters for assessment of intestinal fibrosis in patients with Crohn’s disease
Unveiling the nucleon tensor charge at Jefferson Lab: A study of the SoLID case
Future experiments at the Jefferson Lab 12 GeV upgrade, in particular, the
Solenoidal Large Intensity Device (SoLID), aim at a very precise data set in
the region where the partonic structure of the nucleon is dominated by the
valence quarks. One of the main goals is to constrain the quark transversity
distributions. We apply recent theoretical advances of the global QCD
extraction of the transversity distributions to study the impact of future
experimental data from the SoLID experiments. Especially, we develop a simple
strategy based on the Hessian matrix analysis that allows one to estimate the
uncertainties of the transversity quark distributions and their tensor charges
extracted from SoLID data simulation. We find that the SoLID measurements with
the proton and the effective neutron targets can improve the precision of the
u- and d-quark transversity distributions up to one order of magnitude in the
range 0.05 < x < 0.6.Comment: 11 pages, 3 figures, published on Physics Letters
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