297 research outputs found
Peroxidasin protein expression and enzymatic activity in metastatic melanoma cell lines are associated with invasive potential
Peroxidasin, a heme peroxidase, has been shown to play a role in cancer progression. mRNA expression has been reported to be upregulated in metastatic melanoma cell lines and connected to the invasive phenotype, but little is known about how peroxidasin acts in cancer cells. We have analyzed peroxidasin protein expression and activity in eight metastatic melanoma cell lines using an ELISA developed with an in-house peroxidasin binding protein. RNAseq data analysis confirmed high peroxidasin mRNA expression in the five cell lines classified as invasive and low expression in the three non-invasive cell lines. Protein levels of peroxidasin were higher in the cell lines with an invasive phenotype. Active peroxidasin was secreted to the cell culture medium, where it accumulated over time, and peroxidasin protein levels in the medium were also much higher in invasive than non-invasive cell lines. The only well-established physiological role of peroxidasin is in the formation of a sulfilimine bond, which cross-links collagen IV in basement membranes via catalyzed oxidation of bromide to hypobromous acid. We found that peroxidasin secreted from melanoma cells formed sulfilimine bonds in uncross-linked collagen IV, confirming peroxidasin activity and hypobromous acid formation. Moreover, 3-bromotyrosine, a stable product of hypobromous acid reacting with tyrosine residues, was detected in invasive melanoma cells, substantiating that their expression of peroxidasin generates hypobromous acid, and showing that it does not exclusively react with collagen IV, but also with other biomolecules
An Infinite-Dimensional Family of Black-Hole Microstate Geometries
We construct the first explicit, smooth, horizonless black-hole microstate
geometry whose moduli space is described by an arbitrary function of one
variable and is thus infinite-dimensional. This is achieved by constructing the
scalar Green function on a simple D6 anti-D6 background, and using this Green
function to obtain the fully back-reacted solution for a supertube with varying
charge density in this background. We show that this supertube can store
parametrically more entropy than in flat space, confirming the entropy
enhancement mechanism that was predicted using brane probes. We also show that
all the local properties of the fully back-reacted solution can, in fact, be
obtained using the DBI action of an appropriate brane probe. In particular, the
supergravity and the DBI analysis yield identical functional bubble equations
that govern the relative locations of the centers. This indicates that there is
a non-renormalization theorem that protects these functional equations as one
moves in moduli space. Our construction creates configurations that are beyond
the scope of recent arguments that appear to put strong limits on the entropy
that can be found in smooth supergravity solutions.Comment: 46 pages, 1 figure, LaTe
Cluster M Mycobacteriophages Bongo, PegLeg, and Rey with Unusually Large Repertoires of tRNA Isotopes
Genomic analysis of a large set of phages infecting the common hostMycobacterium smegmatis mc2155 shows that they span considerable genetic diversity. There are more than 20 distinct types that lack nucleotide similarity with each other, and there is considerable diversity within most of the groups. Three newly isolated temperate mycobacteriophages, Bongo, PegLeg, and Rey, constitute a new group (cluster M), with the closely related phages Bongo and PegLeg forming subcluster M1 and the more distantly related Rey forming subcluster M2. The cluster M mycobacteriophages have siphoviral morphologies with unusually long tails, are homoimmune, and have larger than average genomes (80.2 to 83.7 kbp). They exhibit a variety of features not previously described in other mycobacteriophages, including noncanonical genome architectures and several unusual sets of conserved repeated sequences suggesting novel regulatory systems for both transcription and translation. In addition to containing transfer-messenger RNA and RtcB-like RNA ligase genes, their genomes encode 21 to 24 tRNA genes encompassing complete or nearly complete sets of isotypes. We predict that these tRNAs are used in late lytic growth, likely compensating for the degradation or inadequacy of host tRNAs. They may represent a complete set of tRNAs necessary for late lytic growth, especially when taken together with the apparent lack of codons in the same late genes that correspond to tRNAs that the genomes of the phages do not obviously encode
The Fastest Flights in Nature: High-Speed Spore Discharge Mechanisms among Fungi
BACKGROUND: A variety of spore discharge processes have evolved among the fungi. Those with the longest ranges are powered by hydrostatic pressure and include "squirt guns" that are most common in the Ascomycota and Zygomycota. In these fungi, fluid-filled stalks that support single spores or spore-filled sporangia, or cells called asci that contain multiple spores, are pressurized by osmosis. Because spores are discharged at such high speeds, most of the information on launch processes from previous studies has been inferred from mathematical models and is subject to a number of errors. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we have used ultra-high-speed video cameras running at maximum frame rates of 250,000 fps to analyze the entire launch process in four species of fungi that grow on the dung of herbivores. For the first time we have direct measurements of launch speeds and empirical estimates of acceleration in these fungi. Launch speeds ranged from 2 to 25 m s(-1) and corresponding accelerations of 20,000 to 180,000 g propelled spores over distances of up to 2.5 meters. In addition, quantitative spectroscopic methods were used to identify the organic and inorganic osmolytes responsible for generating the turgor pressures that drive spore discharge. CONCLUSIONS/SIGNIFICANCE: The new video data allowed us to test different models for the effect of viscous drag and identify errors in the previous approaches to modeling spore motion. The spectroscopic data show that high speed spore discharge mechanisms in fungi are powered by the same levels of turgor pressure that are characteristic of fungal hyphae and do not require any special mechanisms of osmolyte accumulation
The Atacama Cosmology Telescope: Detection of mm-wave transient sources
We report on the serendipitous discovery of three transient mm-wave sources
using data from the Atacama Cosmology Telescope. The first, detected at RA =
273.8138, dec = -49.4628 at total, brightened from less than 5
mJy to at least 1100 mJy at 150 GHz with an unknown rise time shorter than
thirteen days, during which the increase from 250 mJy to 1100 mJy took only 8
minutes. Maximum flux was observed on 2019-11-8. The source's spectral index in
flux between 90 and 150 GHz was positive, . The second,
detected at RA = 105.1584, dec = -11.2434 at total, brightened
from less than 20 mJy to at least 300 mJy at 150 GHz with an unknown rise time
shorter than eight days. Maximum flux was observed on 2019-12-15. Its spectral
index was also positive, . The third, detected at RA =
301.9952, dec = 16.1652 at total, brightened from less than 8
mJy to at least 300 mJy at 150 GHz over a day or less but decayed over a few
days. Maximum flux was observed on 2018-9-11. Its spectrum was approximately
flat, with a spectral index of . None of the sources were
polarized to the limits of these measurements. The two rising-spectrum sources
are coincident in position with M and K stars, while the third is coincident
with a G star.Comment: 8 pages, 4 figures, 1 tabl
Genetic risk and a primary role for cell-mediated immune mechanisms in multiple sclerosis.
Multiple sclerosis is a common disease of the central nervous system in which the interplay between inflammatory and neurodegenerative processes typically results in intermittent neurological disturbance followed by progressive accumulation of disability. Epidemiological studies have shown that genetic factors are primarily responsible for the substantially increased frequency of the disease seen in the relatives of affected individuals, and systematic attempts to identify linkage in multiplex families have confirmed that variation within the major histocompatibility complex (MHC) exerts the greatest individual effect on risk. Modestly powered genome-wide association studies (GWAS) have enabled more than 20 additional risk loci to be identified and have shown that multiple variants exerting modest individual effects have a key role in disease susceptibility. Most of the genetic architecture underlying susceptibility to the disease remains to be defined and is anticipated to require the analysis of sample sizes that are beyond the numbers currently available to individual research groups. In a collaborative GWAS involving 9,772 cases of European descent collected by 23 research groups working in 15 different countries, we have replicated almost all of the previously suggested associations and identified at least a further 29 novel susceptibility loci. Within the MHC we have refined the identity of the HLA-DRB1 risk alleles and confirmed that variation in the HLA-A gene underlies the independent protective effect attributable to the class I region. Immunologically relevant genes are significantly overrepresented among those mapping close to the identified loci and particularly implicate T-helper-cell differentiation in the pathogenesis of multiple sclerosis
The Atacama Cosmology Telescope: Microwave Intensity and Polarization Maps of the Galactic Center
We present arcminute-resolution intensity and polarization maps of the
Galactic center made with the Atacama Cosmology Telescope (ACT). The maps cover
a 32 deg field at 98, 150, and 224 GHz with ,
. We combine these data with Planck observations at
similar frequencies to create coadded maps with increased sensitivity at large
angular scales. With the coadded maps, we are able to resolve many known
features of the Central Molecular Zone (CMZ) in both total intensity and
polarization. We map the orientation of the plane-of-sky component of the
Galactic magnetic field inferred from the polarization angle in the CMZ,
finding significant changes in morphology in the three frequency bands as the
underlying dominant emission mechanism changes from synchrotron to dust
emission. Selected Galactic center sources, including Sgr A*, the Brick
molecular cloud (G0.253+0.016), the Mouse pulsar wind nebula (G359.23-0.82),
and the Tornado supernova remnant candidate (G357.7-0.1), are examined in
detail. These data illustrate the potential for leveraging ground-based Cosmic
Microwave Background polarization experiments for Galactic science.Comment: 26 pages, 14 figures, accepted for publication in Ap
The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe
The preponderance of matter over antimatter in the early Universe, the
dynamics of the supernova bursts that produced the heavy elements necessary for
life and whether protons eventually decay --- these mysteries at the forefront
of particle physics and astrophysics are key to understanding the early
evolution of our Universe, its current state and its eventual fate. The
Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed
plan for a world-class experiment dedicated to addressing these questions. LBNE
is conceived around three central components: (1) a new, high-intensity
neutrino source generated from a megawatt-class proton accelerator at Fermi
National Accelerator Laboratory, (2) a near neutrino detector just downstream
of the source, and (3) a massive liquid argon time-projection chamber deployed
as a far detector deep underground at the Sanford Underground Research
Facility. This facility, located at the site of the former Homestake Mine in
Lead, South Dakota, is approximately 1,300 km from the neutrino source at
Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino
charge-parity symmetry violation and mass ordering effects. This ambitious yet
cost-effective design incorporates scalability and flexibility and can
accommodate a variety of upgrades and contributions. With its exceptional
combination of experimental configuration, technical capabilities, and
potential for transformative discoveries, LBNE promises to be a vital facility
for the field of particle physics worldwide, providing physicists from around
the globe with opportunities to collaborate in a twenty to thirty year program
of exciting science. In this document we provide a comprehensive overview of
LBNE's scientific objectives, its place in the landscape of neutrino physics
worldwide, the technologies it will incorporate and the capabilities it will
possess.Comment: Major update of previous version. This is the reference document for
LBNE science program and current status. Chapters 1, 3, and 9 provide a
comprehensive overview of LBNE's scientific objectives, its place in the
landscape of neutrino physics worldwide, the technologies it will incorporate
and the capabilities it will possess. 288 pages, 116 figure
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