663 research outputs found
Inhibitors of actin polymerization and calmodulin binding enhance protein kinase C-induced translocation of MARCKS in C6 glioma cells
AbstractMARCKS (myristoylated alanine-rich C-kinase substrate) is known to interact with calmodulin, actin filaments, and anionic phospholipids at a central basic domain which is also the site of phosphorylation by protein kinase C (PKC). In the present study, cytochalasin D (CD) and calmodulin antagonists were used to examine the influence of F-actin and calmodulin on membrane interaction of MARCKS in C6 glioma cells. CD treatment for 1 h disrupted F-actin filaments, increased membrane bound immunoreactive MARCKS (from 51% to 62% of total), yet markedly enhanced the amount of MARCKS translocated to the cytosolic fraction in response to the phorbol ester 4β-12-O-tetradecanoylphorbol 13-acetate. In contrast, CD treatment had no effect on phorbol ester-stimulated phosphorylation of MARCKS or on translocation of PKCα to the membrane fraction. Staurosporine also increased membrane association of MARCKS in a PKC-independent manner, as no change in MARCKS phosphorylation was noted and bis-indolylmaleimide (a more specific PKC inhibitor) did not alter MARCKS distribution. Staurosporine inhibited the phorbol ester-induced translocation of MARCKS but not of PKCα in both CD pretreated and untreated cells. Calmodulin antagonists (trifluoperazine, calmidazolium) had little effect on the cellular distribution or phosphorylation of MARCKS, but were synergistic with phorbol ester in translocating MARCKS from the membrane without a further increase in its phosphorylation. We conclude that cytoskeletal integrity is not required for phosphorylation and translocation of MARCKS in response to activated PKC, but that interaction with both F-actin and calmodulin might serve to independently modulate PKC-regulated localization and function of MARCKS at cellular membranes
The Very Low Albedo of WASP-12b From Spectral Eclipse Observations with
We present an optical eclipse observation of the hot Jupiter WASP-12b using
the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope.
These spectra allow us to place an upper limit of (97.5%
confidence level) on the planet's white light geometric albedo across 290--570
nm. Using six wavelength bins across the same wavelength range also produces
stringent limits on the geometric albedo for all bins. However, our
uncertainties in eclipse depth are 40% greater than the Poisson limit and
may be limited by the intrinsic variability of the Sun-like host star --- the
solar luminosity is known to vary at the level on a timescale of
minutes. We use our eclipse depth limits to test two previously suggested
atmospheric models for this planet: Mie scattering from an aluminum-oxide haze
or cloud-free Rayleigh scattering. Our stringent nondetection rules out both
models and is consistent with thermal emission plus weak Rayleigh scattering
from atomic hydrogen and helium. Our results are in stark contrast with those
for the much cooler HD 189733b, the only other hot Jupiter with spectrally
resolved reflected light observations; those data showed an increase in albedo
with decreasing wavelength. The fact that the first two exoplanets with optical
albedo spectra exhibit significant differences demonstrates the importance of
spectrally resolved reflected light observations and highlights the great
diversity among hot Jupiters.Comment: 8 pages, 4 figures, 1 table, published in ApJL, in pres
Gemini/GMOS Optical Transmission Spectroscopy of WASP-121b: signs of variability in an ultra-hot Jupiter?
We present ground-based, spectroscopic observations of two transits of the
ultra-hot Jupiter WASP-121b covering the wavelength range 500 - 950 nm
using Gemini/GMOS. We use a Gaussian process framework to model instrumental
systematics in the light curves, and also demonstrate the use of the more
generalised Student's-T process to verify our results. We find that our
measured transmission spectrum, whilst showing overall agreement, is slightly
discrepant with results obtained using HST/STIS, particularly for wavelengths
shortward of 650 nm. In contrast to the STIS results, we find evidence
for an increasing blueward slope and little evidence for absorption from either
TiO or VO in our retrieval, in agreement with a number of recent studies
performed at high-resolution. We suggest that this might point to some other
absorbers, particularly some combination of recently detected atomic metals, in
addition to scattering by hazes, being responsible for the excess optical
absorption and observed vertical thermal inversion. Our results are also
broadly consistent with previous ground-based photometry and 3D GCM
predictions, however, these assumed different chemistry to our retrievals. In
addition, we show that the GMOS observations are repeatable over short periods
(days), similarly to the HST/STIS observations. Their difference over longer
periods (months) could well be the result of temporal variability in the
atmospheric properties (i.e. weather) as predicted by theoretical models of
ultra-hot Jupiters; however, more mundane explanations such as instrumental
systematics and stellar activity cannot be fully ruled out, and we encourage
future observations to explore this possibility.Comment: 17 pages, 10 Figures. Accepted for publication in MNRA
Benefits for Type 2 Diabetes of Interrupting Prolonged Sitting With Brief Bouts of Light Walking or Simple Resistance Activities
OBJECTIVE To determine whether interrupting prolonged sitting with brief bouts of light-intensity walking (LW) or simple resistance activities (SRA) improves postprandial cardiometabolic risk markers in adults with type 2 diabetes (T2D). RESEARCH DESIGN AND METHODS In a randomized crossover trial, 24 inactive overweight/obese adults with T2D (14 men 62 ± 6 years old) underwent the following 8-h conditions on three separate days (with 6–14 days washout): uninterrupted sitting (control) (SIT), sitting plus 3-min bouts of LW (3.2 km · h−1) every 30 min, and sitting plus 3-min bouts of SRA (half-squats, calf raises, gluteal contractions, and knee raises) every 30 min. Standardized meals were consumed during each condition. Incremental areas under the curve (iAUCs) for glucose, insulin, C-peptide, and triglycerides were compared between conditions. RESULTS Compared with SIT, both activity-break conditions significantly attenuated iAUCs for glucose (SIT mean 24.2 mmol · h · L−1 [95% CI 20.4–28.0] vs. LW 14.8 [11.0–18.6] and SRA 14.7 [10.9–18.5]), insulin (SIT 3,293 pmol · h · L−1 [2,887–3,700] vs. LW 2,104 [1,696–2,511] and SRA 2,066 [1,660–2,473]), and C-peptide (SIT 15,641 pmol · h · L−1 [14,353–16,929] vs. LW 11,504 [10,209–12,799] and SRA 11,012 [9,723–12,301]) (all P < 0.001). The iAUC for triglycerides was significantly attenuated for SRA (P < 0.001) but not for LW (SIT 4.8 mmol · h · L−1 [3.6–6.0] vs. LW 4.0 [2.8–5.1] and SRA 2.9 [1.7–4.1]). CONCLUSIONS Interrupting prolonged sitting with brief bouts of LW or SRA attenuates acute postprandial glucose, insulin, C-peptide, and triglyceride responses in adults with T2D. With poor adherence to structured exercise, this approach is potentially beneficial and practical
Transiting Exoplanet Studies and Community Targets for JWST's Early Release Science Program
The James Webb Space Telescope will revolutionize transiting exoplanet
atmospheric science due to its capability for continuous, long-duration
observations and its larger collecting area, spectral coverage, and spectral
resolution compared to existing space-based facilities. However, it is unclear
precisely how well JWST will perform and which of its myriad instruments and
observing modes will be best suited for transiting exoplanet studies. In this
article, we describe a prefatory JWST Early Release Science (ERS) program that
focuses on testing specific observing modes to quickly give the community the
data and experience it needs to plan more efficient and successful future
transiting exoplanet characterization programs. We propose a multi-pronged
approach wherein one aspect of the program focuses on observing transits of a
single target with all of the recommended observing modes to identify and
understand potential systematics, compare transmission spectra at overlapping
and neighboring wavelength regions, confirm throughputs, and determine overall
performances. In our search for transiting exoplanets that are well suited to
achieving these goals, we identify 12 objects (dubbed "community targets") that
meet our defined criteria. Currently, the most favorable target is WASP-62b
because of its large predicted signal size, relatively bright host star, and
location in JWST's continuous viewing zone. Since most of the community targets
do not have well-characterized atmospheres, we recommend initiating preparatory
observing programs to determine the presence of obscuring clouds/hazes within
their atmospheres. Measurable spectroscopic features are needed to establish
the optimal resolution and wavelength regions for exoplanet characterization.
Other initiatives from our proposed ERS program include testing the instrument
brightness limits and performing phase-curve observations.(Abridged)Comment: This is a white paper that originated from an open discussion at the
Enabling Transiting Exoplanet Science with JWST workshop held November 16 -
18, 2015 at STScI (http://www.stsci.edu/jwst/science/exoplanets). Accepted
for publication in PAS
Risk variants and polygenic architecture of disruptive behavior disorders in the context of attention-deficit/hyperactivity disorder
Attention-Deficit/Hyperactivity Disorder (ADHD) is a childhood psychiatric disorder often comorbid with disruptive behavior disorders (DBDs). Here, we report a GWAS meta-analysis of ADHD comorbid with DBDs (ADHD + DBDs) including 3802 cases and 31,305 controls. We identify three genome-wide significant loci on chromosomes 1, 7, and 11. A meta-analysis including a Chinese cohort supports that the locus on chromosome 11 is a strong risk locus for ADHD + DBDs across European and Chinese ancestries (rs7118422, P = 3.15×10-10, OR = 1.17). We find a higher SNP heritability for ADHD + DBDs (h2SNP = 0.34) when compared to ADHD without DBDs (h2SNP = 0.20), high genetic correlations between ADHD + DBDs and aggressive (rg = 0.81) and anti-social behaviors (rg = 0.82), and an increased burden (polygenic score) of variants associated with ADHD and aggression in ADHD + DBDs compared to ADHD without DBDs. Our results suggest an increased load of common risk variants in ADHD + DBDs compared to ADHD without DBDs, which in part can be explained by variants associated with aggressive behavior
ACCESS & LRG-BEASTS: a precise new optical transmission spectrum of the ultrahot Jupiter WASP-103b
We present a new ground-based optical transmission spectrum of the ultrahot
Jupiter WASP-103b (K). Our transmission spectrum is the result
of combining five new transits from the ACCESS survey and two new transits from
the LRG-BEASTS survey with a reanalysis of three archival Gemini/GMOS transits
and one VLT/FORS2 transit. Our combined 11-transit transmission spectrum covers
a wavelength range of 3900--9450A with a median uncertainty in the transit
depth of 148 parts-per-million, which is less than one atmospheric scale height
of the planet. In our retrieval analysis of WASP-103b's combined optical and
infrared transmission spectrum, we find strong evidence for unocculted bright
regions () and weak evidence for HO (), HCN
(), and TiO (), which could be responsible for
WASP-103b's observed temperature inversion. Our optical transmission spectrum
shows significant structure that is in excellent agreement with the extensively
studied ultrahot Jupiter WASP-121b, for which the presence of VO has been
inferred. For WASP-103b, we find that VO can only provide a reasonable fit to
the data if its abundance is implausibly high and we do not account for stellar
activity. Our results highlight the precision that can be achieved by
ground-based observations and the impacts that stellar activity from F-type
stars can have on the interpretation of exoplanet transmission spectra.Comment: 33 pages, 17 figures, 7 tables. Accepted for publication in A
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Conifer DBMagic: a database housing multiple de novo transcriptome assemblies for 12 diverse conifer species
Conifers comprise an ancient and widespread plant lineage of enormous commercial and ecological value. However, compared to model woody angiosperms, such as Populus and Eucalyptus, our understanding of conifers remains quite limited at a genomic level. Large genome sizes (10,000–40,000 Mbp) and large amounts of repetitive DNA have limited efforts to produce a conifer reference genome, and genomic resource development has focused primarily on characterization of expressed sequences. Here, we report the completion of a conifer transcriptome sequencing project undertaken in collaboration with the U.S. DOE Joint Genome Institute that resulted in production of almost 12 million sequence reads. Five loblolly pine (Pinus taeda) cDNA libraries representing multiple tissues, treatments, and genotypes produced over four million sequence reads that, along with available Sanger expressed sequence tags, were used to create contig assemblies using three different assembly algorithms: Newbler, MiraEST, and NGen. In addition, libraries from 11 other conifer species, as well as one member of the Gnetales (Gnetum gnemon), produced 0.4 to 1.2 million sequence reads each. Among the selected conifer species were representatives of each of the seven phylogenetic families in the Coniferales: Araucariaceae, Cephalotaxaceae, Cupressaceae, Pinaceae, Podocarpaceae, Sciadopityaceae, and Taxaceae. Transcriptome builds for each species were generated using each of the three assemblers. All contigs for every species generated using each assembler can be obtained from Conifer DBMagic, a public database for searching, viewing, and downloading contig sequences, the associated sequence reads, and their annotations.Keywords: Database,
Gene models,
Pinus,
Comparative phylogenomics,
Annotation,
Transcriptome,
Coniferale
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