1,587 research outputs found
Recommended from our members
Anatomical localization of progenitor cells in human breast tissue reveals enrichment of uncommitted cells within immature lobules
Introduction: Lineage tracing studies in mice have revealed the localization and existence of lineage-restricted mammary epithelial progenitor cells that functionally contribute to expansive growth during puberty and differentiation during pregnancy. However, extensive anatomical differences between mouse and human mammary tissues preclude the direct translation of rodent findings to the human breast. Therefore, here we characterize the mammary progenitor cell hierarchy and identify the anatomic location of progenitor cells within human breast tissues. Methods: Mammary epithelial cells (MECs) were isolated from disease-free reduction mammoplasty tissues and assayed for stem/progenitor activity in vitro and in vivo. MECs were sorted and evaluated for growth on collagen and expression of lineages markers. Breast lobules were microdissected and individually characterized based on lineage markers and steroid receptor expression to identify the anatomic location of progenitor cells. Spanning-tree progression analysis of density-normalized events (SPADE) was used to identify the cellular hierarchy of MECs within lobules from high-dimensional cytometry data. Results: Integrating multiple assays for progenitor activity, we identified the presence of luminal alveolar and basal ductal progenitors. Further, we show that Type I lobules of the human breast were the least mature, demonstrating an unrestricted pattern of expression of luminal and basal lineage markers. Consistent with this, SPADE analysis revealed that immature lobules were enriched for basal progenitor cells, while mature lobules consisted of increased hierarchal complexity of cells within the luminal lineages. Conclusions: These results reveal underlying differences in the human breast epithelial hierarchy and suggest that with increasing glandular maturity, the epithelial hierarchy also becomes more complex. Electronic supplementary material The online version of this article (doi:10.1186/s13058-014-0453-3) contains supplementary material, which is available to authorized users
Exploring the Local Milky Way: M Dwarfs as Tracers of Galactic Populations
We have assembled a spectroscopic sample of low-mass dwarfs observed as part
of the Sloan Digital Sky Survey along one Galactic sightline, designed to
investigate the observable properties of the thin and thick disks. This sample
of ~7400 K and M stars also has measured ugriz photometry, proper motions, and
radial velocities. We have computed UVW space motion distributions, and
investigate their structure with respect to vertical distance from the Galactic
Plane. We place constraints on the velocity dispersions of the thin and thick
disks, using two-component Gaussian fits. We also compare these kinematic
distributions to a leading Galactic model. Finally, we investigate other
possible observable differences between the thin and thick disks, such as
color, active fraction and metallicity.Comment: 11 pages, 12 figures, Accepted by A
Isotopic evidence for long-distance connections of the AD thirteenth century Promontory caves occupants
Las cuevas Promontory (Utah) y la Cueva Franktown (Colorado) contienen registros de alta fidelidad en cuanto a las ocupaciones de corto término de grupos humanos con cultura material conectada al Subártico/Planicies del Norte. Esta investigación utiliza excremento, pelo, piel de cuero y colágeno del hueso de bisonte provenientes de los sitios Promontory y Franktown para establecer una base de datos isotópicos locales y variabilidad isotópica de carbono e identifica la piel de cuero de procedencia lejana. La envoltura de tobillo de un mocasín recuperado de la Cueva 1 de Promontory tuvo un valor δ13C que indica un componente C4 considerable en la dieta del animal, lo que es un resultado distinto a las dietas C3 que se identificaron a partir del análisis de 171 muestras de bisonte provenientes de Promontory y el norte de Utah. Aplicamos una combinación única de análisis isotópico de tejidos múltiples, mapas isotópicos (“isoscapes”) de carbono, ADN antiguo (identificación de sexo y especie), tasa de remodelación de tejidos, contextos arqueológicos y la ecología del bisonte para demonstrar que el valor alto δ13C probablemente no es un resultado debido al consumo de plantas locales, movilidad del bisonte o comercio. En cambio, la piel de cuero del bisonte fue probablemente adquirida a través de viajes de larga distancia hacia zonas con pastos C4 abundantes muy al sur o al este. El conocimiento extenso sobre el paisaje obtenido a través de asociaciones de larga distancia debió permitir a los habitantes de las cuevas Promontory tomar decisiones bien informadas sobre las direcciones y rutas de movimiento para realizar un cambio territorial, el cual parece haber ocurrido a finales del sigo XIII.The Promontory caves (Utah) and Franktown Cave (Colorado) contain high-fidelity records of short-term occupations by groups with material culture connections to the Subarctic/Northern Plains. This research uses Promontory and Franktown bison dung, hair, hide, and bone collagen to establish local baseline carbon isotopic variability and identify leather from a distant source. The ankle wrap of one Promontory Cave 1 moccasin had a δ13C value that indicates a substantial C4 component to the animal's diet, unlike the C3 diets inferred from 171 other Promontory and northern Utah bison samples. We draw on a unique combination of multitissue isotopic analysis, carbon isoscapes, ancient DNA (species and sex identification), tissue turnover rates, archaeological contexts, and bison ecology to show that the high δ13C value was not likely a result of local plant consumption, bison mobility, or trade. Instead, the bison hide was likely acquired via long-distance travel to/from an area of abundant C4 grasses far to the south or east. Expansive landscape knowledge gained through long-distance associations would have allowed Promontory caves inhabitants to make well-informed decisions about directions and routes of movement for a territorial shift, which seems to have occurred in the late thirteenth century
Early-branching gut fungi possess a large, comprehensive array of biomass-degrading enzymes
available in PMC 2016 November 07The fungal kingdom is the source of almost all industrial enzymes in use for lignocellulose bioprocessing. We developed a systems-level approach that integrates transcriptomic sequencing, proteomics, phenotype, and biochemical studies of relatively unexplored basal fungi. Anaerobic gut fungi isolated from herbivores produce a large array of biomass-degrading enzymes that synergistically degrade crude, untreated plant biomass and are competitive with optimized commercial preparations from Aspergillus and Trichoderma. Compared to these model platforms, gut fungal enzymes are unbiased in substrate preference due to a wealth of xylan-degrading enzymes. These enzymes are universally catabolite-repressed and are further regulated by a rich landscape of noncoding regulatory RNAs. Additionally, we identified several promising sequence-divergent enzyme candidates for lignocellulosic bioprocessing.United States. Dept. of Energy. Office of Science (Biological and Environmental Research (BER) program)United States. Department of Energy (DOE Grant DE-SC0010352)United States. Department of Agriculture (Award 2011-67017-20459)Institute for Collaborative Biotechnologies (grant W911NF-09-0001
LSST: from Science Drivers to Reference Design and Anticipated Data Products
(Abridged) We describe here the most ambitious survey currently planned in
the optical, the Large Synoptic Survey Telescope (LSST). A vast array of
science will be enabled by a single wide-deep-fast sky survey, and LSST will
have unique survey capability in the faint time domain. The LSST design is
driven by four main science themes: probing dark energy and dark matter, taking
an inventory of the Solar System, exploring the transient optical sky, and
mapping the Milky Way. LSST will be a wide-field ground-based system sited at
Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m
effective) primary mirror, a 9.6 deg field of view, and a 3.2 Gigapixel
camera. The standard observing sequence will consist of pairs of 15-second
exposures in a given field, with two such visits in each pointing in a given
night. With these repeats, the LSST system is capable of imaging about 10,000
square degrees of sky in a single filter in three nights. The typical 5
point-source depth in a single visit in will be (AB). The
project is in the construction phase and will begin regular survey operations
by 2022. The survey area will be contained within 30,000 deg with
, and will be imaged multiple times in six bands, ,
covering the wavelength range 320--1050 nm. About 90\% of the observing time
will be devoted to a deep-wide-fast survey mode which will uniformly observe a
18,000 deg region about 800 times (summed over all six bands) during the
anticipated 10 years of operations, and yield a coadded map to . The
remaining 10\% of the observing time will be allocated to projects such as a
Very Deep and Fast time domain survey. The goal is to make LSST data products,
including a relational database of about 32 trillion observations of 40 billion
objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures
available from https://www.lsst.org/overvie
Hip joint articular soft tissues of non-dinosaurian Dinosauromorpha and early Dinosauria: evolutionary and biomechanical implications for Saurischia
Dinosauromorphs evolved a wide diversity of hind limb skeletal morphologies, suggesting highly divergent articular soft tissue anatomies. However, poor preservation of articular soft tissues in fossils has hampered any follow-on functional inferences. We reconstruct the hip joint soft tissue anatomy of non-dinosaurian dinosauromorphs and early dinosaurs using osteological correlates derived from extant sauropsids and infer trends in character transitions along the theropod and sauropodomorph lineagues. Femora and pelves of 107 dinosauromorphs and outgroup taxa were digitized using 3D imaging techniques. Key transitions were estimated using maximum likelihood ancestral state reconstruction. The hips of dinosauromorphs possessed wide a disparity of soft tissue morphologies beyond the types and combinations exhibited by extant archosaurs. Early evolution of the dinosauriform hip joint was characterized by the retention of a prominent femoral hyaline cartilage cone in post-neonatal individuals, with the cartilage cone independently reduced within theropods and sauropodomorphs. The femur of Dinosauriformes possessed a fibrocartilage sleeve on the metaphysis, which surrounded a hyaline core. The acetabulum of Dinosauriformes possessed distinct labrum and antitrochanter structures. In sauropodomorphs, hip congruence was maintained by thick hyaline cartilage on the femoral head, whereas theropods relied on acetabular tissues such as ligaments and articular pads. In particular, the craniolaterally ossified hip capsule of non- Avetheropoda neotheropods permitted mostly parasagittal femoral movements. These data indicate that the dinosauromorph hip underwent mosaic evolution within the saurischian lineage and that sauropodomorphs and theropods underwent both convergence and divergence in articular soft tissues, correlated with transitions in body size, locomotor posture, and joint loading
LSST Science Book, Version 2.0
A survey that can cover the sky in optical bands over wide fields to faint
magnitudes with a fast cadence will enable many of the exciting science
opportunities of the next decade. The Large Synoptic Survey Telescope (LSST)
will have an effective aperture of 6.7 meters and an imaging camera with field
of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over
20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with
fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a
total point-source depth of r~27.5. The LSST Science Book describes the basic
parameters of the LSST hardware, software, and observing plans. The book
discusses educational and outreach opportunities, then goes on to describe a
broad range of science that LSST will revolutionize: mapping the inner and
outer Solar System, stellar populations in the Milky Way and nearby galaxies,
the structure of the Milky Way disk and halo and other objects in the Local
Volume, transient and variable objects both at low and high redshift, and the
properties of normal and active galaxies at low and high redshift. It then
turns to far-field cosmological topics, exploring properties of supernovae to
z~1, strong and weak lensing, the large-scale distribution of galaxies and
baryon oscillations, and how these different probes may be combined to
constrain cosmological models and the physics of dark energy.Comment: 596 pages. Also available at full resolution at
http://www.lsst.org/lsst/sciboo
Amplicon-Based Detection and Sequencing of SARS-CoV-2 in Nasopharyngeal Swabs from Patients With COVID-19 and Identification of Deletions in the Viral Genome That Encode Proteins Involved in Interferon Antagonism
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of coronavirus disease 2019 (COVID-19). Sequencing the viral genome as the outbreak progresses is important, particularly in the identification of emerging isolates with different pathogenic potential and to identify whether nucleotide changes in the genome will impair clinical diagnostic tools such as real-time PCR assays. Although single nucleotide polymorphisms and point mutations occur during the replication of coronaviruses, one of the biggest drivers in genetic change is recombination. This can manifest itself in insertions and/or deletions in the viral genome. Therefore, sequencing strategies that underpin molecular epidemiology and inform virus biology in patients should take these factors into account. A long amplicon/read length-based RT-PCR sequencing approach focused on the Oxford Nanopore MinION/GridION platforms was developed to identify and sequence the SARS-CoV-2 genome in samples from patients with or suspected of COVID-19. The protocol, termed Rapid Sequencing Long Amplicons (RSLAs) used random primers to generate cDNA from RNA purified from a sample from a patient, followed by single or multiplex PCRs to generate longer amplicons of the viral genome. The base protocol was used to identify SARS-CoV-2 in a variety of clinical samples and proved sensitive in identifying viral RNA in samples from patients that had been declared negative using other nucleic acid-based assays (false negative). Sequencing the amplicons revealed that a number of patients had a proportion of viral genomes with deletions
Construction of a large scale integrated map of macrophage pathogen recognition and effector systems
<p>Abstract</p> <p>Background</p> <p>In an effort to better understand the molecular networks that underpin macrophage activation we have been assembling a map of relevant pathways. Manual curation of the published literature was carried out in order to define the components of these pathways and the interactions between them. This information has been assembled into a large integrated directional network and represented graphically using the modified Edinburgh Pathway Notation (mEPN) scheme.</p> <p>Results</p> <p>The diagram includes detailed views of the toll-like receptor (TLR) pathways, other pathogen recognition systems, NF-kappa-B, apoptosis, interferon signalling, MAP-kinase cascades, MHC antigen presentation and proteasome assembly, as well as selected views of the transcriptional networks they regulate. The integrated pathway includes a total of 496 unique proteins, the complexes formed between them and the processes in which they are involved. This produces a network of 2,170 nodes connected by 2,553 edges.</p> <p>Conclusions</p> <p>The pathway diagram is a navigable visual aid for displaying a consensus view of the pathway information available for these systems. It is also a valuable resource for computational modelling and aid in the interpretation of functional genomics data. We envisage that this work will be of value to those interested in macrophage biology and also contribute to the ongoing Systems Biology community effort to develop a standard notation scheme for the graphical representation of biological pathways.</p
The Milky Way Tomography with SDSS: II. Stellar Metallicity
Using effective temperature and metallicity derived from SDSS spectra for
~60,000 F and G type main sequence stars (0.2<g-r<0.6), we develop polynomial
models for estimating these parameters from the SDSS u-g and g-r colors. We
apply this method to SDSS photometric data for about 2 million F/G stars and
measure the unbiased metallicity distribution for a complete volume-limited
sample of stars at distances between 500 pc and 8 kpc. The metallicity
distribution can be exquisitely modeled using two components with a spatially
varying number ratio, that correspond to disk and halo. The two components also
possess the kinematics expected for disk and halo stars. The metallicity of the
halo component is spatially invariant, while the median disk metallicity
smoothly decreases with distance from the Galactic plane from -0.6 at 500 pc to
-0.8 beyond several kpc. The absence of a correlation between metallicity and
kinematics for disk stars is in a conflict with the traditional decomposition
in terms of thin and thick disks. We detect coherent substructures in the
kinematics--metallicity space, such as the Monoceros stream, which rotates
faster than the LSR, and has a median metallicity of [Fe/H]=-0.96, with an rms
scatter of only ~0.15 dex. We extrapolate our results to the performance
expected from the Large Synoptic Survey Telescope (LSST) and estimate that the
LSST will obtain metallicity measurements accurate to 0.2 dex or better, with
proper motion measurements accurate to ~0.2 mas/yr, for about 200 million F/G
dwarf stars within a distance limit of ~100 kpc (g<23.5). [abridged]Comment: 40 pages, 21 figures, emulateApJ style, accepted to ApJ, high
resolution figures are available from
http://www.astro.washington.edu/ivezic/sdss/mw/astroph0804.385
- …