451 research outputs found
Abundance and diversity of predominant sulfate-reducing bacteria in the gut of pufferfish
Sulfate-reducing bacteria (SRB) exist in anaerobic environments, such as marine sediments, and produce hydrogen sulfide, which is toxic to marine animals. However, little is known about the ecology of SRB in the gut of fish. In the present study, we used molecular techniques to analyze the predominant SRB community in the gut of pufferfish inhabiting coastal areas of Japan. The density of the dissimilatory sulfite reductase alpha gene, dsrA, derived from SRB and total count of bacteria in guts of pufferfish was 4.4í—106 - 1.8í—107 copies/g and 3.5í—108 - 6.3í—109 cells/g, respectively, in all specimens. Clones of dsrA associated with Desulfobulbus oligotrophicus, a dominant SRB species, were detected in all 12 libraries, accounting for 57.7-94.3% of clones in each library. These results strongly suggest that SRB are indigenous bacteria in the gut of pufferfish and that hydrogen sulfide produced by SRB may be a risk factor for fish health
Analysis of the anti-tumor mechanism of BRD4 inhibition in hepatocellular carcinoma
Bromodomain and extra terminal (BET) family proteins, which include BRD4, are readers of histone acetyl-lysines and key regulators of gene transcription. BRD4 inhibitors exert anti-tumor effects in various cancers, including hepatocellular carcinoma (HCC). We investigated the mechanism underlying the antitumor effects of BRD4 inhibition in HCC. We first tested the effects of the BRD4 inhibitor JQ1 in a series of 9 HCC cell lines and found that it strongly suppressed HCC cell proliferation by inducing cell cycle arrest and apoptosis. Gene expression microarray analysis revealed that JQ1 also induced marked changes in the gene expression profiles of HCC cells, and genes associated with cell cycle and apoptosis were significantly enriched among the affected genes. Notably, a number of cancer-related genes, including BCAT1, DDR1, GDF15, FANCD2, SENP1 and TYRO3, were strongly suppressed by JQ1 in HCC cells. We also confirmed BRD4 bound within the promoter regions of these genes, which suggests they are targets of BRD4 in HCC cells. JQ1 thus appears to exert its anti-tumor effects in HCC by suppressing multiple BRD4 target genes
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Psychosocial twin cohort studies in Japan: the Keio Twin Research Center (KoTReC)
The Keio Twin Research Center (KoTReC) was established in 2009 at Keio University to combine two longitudinal cohort projects — the Keio Twin Study (KTS) for adolescence and adulthood and the Tokyo Twin Cohort Project (ToTCoP) for infancy and childhood. KoTReC also conducted a two-time panel study of self-control and psychopathology in twin adolescence in 2012 and 2013 and three independent anonymous cross-sectional twin surveys (ToTcross) before 2012 — the ToTCross, the Junior and Senior High School Survey and the High School Survey. This article introduces the recent research designs of KoTReC and its publications
Effects of inhomogeneities on apparent cosmological observables: "fake" evolving dark energy
Using the exact Lemaitre-Bondi-Tolman solution with a non-vanishing
cosmological constant , we investigate how the presence of a local
spherically-symmetric inhomogeneity can affect apparent cosmological
observables, such as the deceleration parameter or the effective equation of
state of dark energy (DE), derived from the luminosity distance under the
assumption that the real space-time is exactly homogeneous and isotropic. The
presence of a local underdensity is found to produce apparent phantom behavior
of DE, while a locally overdense region leads to apparent quintessence
behavior. We consider relatively small large scale inhomogeneities which today
are not linear and could be seeded by primordial curvature perturbations
compatible with CMB bounds. Our study shows how observations in an
inhomogeneous CDM universe with initial conditions compatible with the
inflationary beginning, if interpreted under the wrong assumption of
homogeneity, can lead to the wrong conclusion about the presence of "fake"
evolving dark energy instead of .Comment: 22 pages, 19 figures,Final version to appear in European Physical
Journal
Aggregation of scaffolding protein DISC1 dysregulates phosphodiesterase 4 in Huntington’s disease
Huntington’s disease (HD) is a polyglutamine (polyQ) disease caused by aberrant expansion of the polyQ tract in Huntingtin (HTT). While motor impairment mediated by polyQ-expanded HTT has been intensively studied, molecular mechanisms for nonmotor symptoms in HD, such as psychiatric manifestations, remain elusive. Here we have demonstrated that HTT forms a ternary protein complex with the scaffolding protein DISC1 and cAMP-degrading phosphodiesterase 4 (PDE4) to regulate PDE4 activity. We observed pathological cross-seeding between DISC1 and mutant HTT aggregates in the brains of HD patients as well as in a murine model that recapitulates the polyQ pathology of HD (R6/2 mice). In R6/2 mice, consequent reductions in soluble DISC1 led to dysregulation of DISC1-PDE4 complexes, aberrantly increasing the activity of PDE4. Importantly, exogenous expression of a modified DISC1, which binds to PDE4 but not mutant HTT, normalized PDE4 activity and ameliorated anhedonia in the R6/2 mice. We propose that cross-seeding of mutant HTT and DISC1 and the resultant changes in PDE4 activity may underlie the pathology of a specific subset of mental manifestations of HD, which may provide an insight into molecular signaling in mental illness in general
Seasonal and regional characterization of horizontal stirring in the global ocean
Recent work on Lagrangian descriptors has shown that Lyapunov Exponents can
be applied to observed or simulated data to characterize the horizontal
stirring and transport properties of the oceanic flow. However, a more detailed
analysis of regional dependence and seasonal variability was still lacking. In
this paper, we analyze the near-surface velocity field obtained from the Ocean
general circulation model For the Earth Simulator (OFES) using Finite-Size
Lyapunov Exponents (FSLE). We have characterized regional and seasonal
variability. Our results show that horizontal stirring, as measured by FSLEs,
is seasonally-varying, with maximum values in Summer time. FSLEs also strongly
vary depending on the region: we have first characterized the stirring
properties of Northern and Southern Hemispheres, then the main oceanic basins
and currents. We have finally studied the relation between averages of FSLE and
some Eulerian descriptors such as Eddy Kinetic Energy (EKE) and vorticity (w)
over the different regions.Comment: 32 pages, 7 figure
Expanding the Repertoire of Optogenetically Targeted Cells with an Enhanced Gene Expression System
Optogenetics has been enthusiastically pursued in recent neuroscience research, and the causal relationship between neural activity and behavior is becoming ever more accessible. Here, we established knockin-mediated enhanced gene expression by improved tetracycline-controlled gene induction (KENGE-tet) and succeeded in generating transgenic mice expressing a highly light-sensitive channelrhodopsin-2 mutant at levels sufficient to drive the activities of multiple cell types. This method requires two lines of mice: one that controls the pattern of expression and another that determines the protein to be produced. The generation of new lines of either type readily expands the repertoire to choose from. In addition to neurons, we were able to manipulate the activity of nonexcitable glial cells in vivo. This shows that our system is applicable not only to neuroscience but also to any biomedical study that requires understanding of how the activity of a selected population of cells propagates through the intricate organic systems
Enhancing passive radiative cooling properties of flexible CIGS solar cells for space applications using single layer silicon oxycarbonitride films
Satellites in lower earth orbits have been primarily powered by photovoltaic modules. With growing power demand for new satellite concepts, solar cells are required to be flexible and ultra-lightweight to decrease launch costs. CIGS thin film solar technology is a promising candidate, since it can be manufactured on flexible substrates and possesses high radiation hardness. Poor radiative properties of CIGS on the other hand, lead to high temperatures and therefore power loss. High emissivity coatings on CIGS have already been reported but the influence on thermal and electrical aspects have not been addressed. Here we present the optical properties of silicon-oxycarbonitride coatings and their effect on electrical parameters on CIGS cells to be used for the DLR's GoSolAr power sail mission. We show that the single layer coating can significantly increase emissivity from 0.3 to 0.72, with minimal spectral losses and negligible impact on the functioning of the underlying CIGS cell. We simulated the thermal impact of the coating on solar cells in orbit and can predict that the maximum temperature of the cells is reduced by 30 °C, resulting in a significant power gain. Additionally, the coating has an emissivity of 0.87 in the atmospheric window of 8–13 μm making it a very good passive radiative cooler for terrestrial solar cells. The low-cost coating can replace glass and the process can be scaled up for large CIGS modules. The coating can also significantly increase the power to mass ratio of solar modules, reducing costs for space applications
Mass and Hot Baryons in Massive Galaxy Clusters from Subaru Weak Lensing and AMiBA SZE Observations
We present a multiwavelength analysis of a sample of four hot (T_X>8keV)
X-ray galaxy clusters (A1689, A2261, A2142, and A2390) using joint AMiBA
Sunyaev-Zel'dovich effect (SZE) and Subaru weak lensing observations, combined
with published X-ray temperatures, to examine the distribution of mass and the
intracluster medium (ICM) in massive cluster environments. Our observations
show that A2261 is very similar to A1689 in terms of lensing properties. Many
tangential arcs are visible around A2261, with an effective Einstein radius
\sim 40 arcsec (at z \sim 1.5), which when combined with our weak lensing
measurements implies a mass profile well fitted by an NFW model with a high
concentration c_{vir} \sim 10, similar to A1689 and to other massive clusters.
The cluster A2142 shows complex mass substructure, and displays a shallower
profile (c_{vir} \sim 5), consistent with detailed X-ray observations which
imply recent interaction. The AMiBA map of A2142 exhibits an SZE feature
associated with mass substructure lying ahead of the sharp north-west edge of
the X-ray core suggesting a pressure increase in the ICM. For A2390 we obtain
highly elliptical mass and ICM distributions at all radii, consistent with
other X-ray and strong lensing work. Our cluster gas fraction measurements,
free from the hydrostatic equilibrium assumption, are overall in good agreement
with published X-ray and SZE observations, with the sample-averaged gas
fraction of = 0.133 \pm 0.027, for our sample = (1.2 \pm
0.1) \times 10^{15} M_{sun} h^{-1}. When compared to the cosmic baryon fraction
f_b = \Omega_b/\Omega_m constrained by the WMAP 5-year data, this indicates
/f_b = 0.78 \pm 0.16, i.e., (22 \pm 16)% of the baryons are missing
from the hot phase of clusters.Comment: accepted for publication in ApJ; high resolution figures available at
http://www.asiaa.sinica.edu.tw/~keiichi/upfiles/AMiBA7/ms_highreso.pd
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