596 research outputs found
Phylogenetic Relationship of the Complete Rauscher Murine Leukemia Virus Genome with Other Murine Leukemia Virus Genomes
AbstractWe report the complete nucleotide sequence of the genome of Rauscher murine leukemia virus (R-MuLV), the replication-competent helper virus present in the Rauscher virus complex, and its phylogenetic relationship with other murine leukemia virus genomes. An overall sequence identity of 97.6% was found between R-MuLV and the Friend helper virus (F-MuLV), and the two viruses were closely related on the phylogenetic trees constructed from eithergag, pol,orenvsequences. Moloney murine leukemia virus (Mo-MuLV) was the next closest relative to R-MuLV and F-MuLV on all trees, followed by Akv and radiation leukemia virus (RadLV). The most distantly related helper virus was Hortulanus murine leukemia virus (Ho-MuLV). Interestingly, Cas-Br-E branched with Mo-MuLV on thegagandpoltrees, whereas on theenvtree, it revealed the highest degree of relatedness to Ho-MuLV, possibly due to an ancient recombination with an Ho-MuLV ancestor. In summary, a phylogenetic analysis involving various MuLVs has been performed, in which the postulated close relationship between R-MuLV and F-MuLV has been confirmed, consistent with the pathobiology of the two viruses
Characterization of three pyranose dehydrogenase isoforms from the litter-decomposing basidiomycete Leucoagaricus meleagris (syn. Agaricus meleagris)
Nicht verfügbarMultigenicity is commonly found in fungal enzyme systems, with the purpose of functional compensation upon deficiency of one of its members or leading to enzyme isoforms with new functionalities through gene diversification. Three genes of the flavin-dependent glucosemethanolcholine (GMC) oxidoreductase pyranose dehydrogenase (AmPDH) were previously identified in the litter-degrading fungus Agaricus (Leucoagaricus) meleagris, of which only AmPDH1 was successfully expressed and characterized. The aim of this work was to study the biophysical and biochemical properties of AmPDH2 and AmPDH3 and compare them with those of AmPDH1. AmPDH1, AmPDH2 and AmPDH3 showed negligible oxygen reactivity and possess a covalently tethered FAD cofactor. All three isoforms can oxidise a range of different monosaccarides and oligosaccharides including glucose, mannose, galactose and xylose, which are the main constituent sugars of cellulose and hemicelluloses, and judging from the apparent steady-state kinetics determined for these sugars, the three isoforms do not show significant differences pertaining to their reaction with sugar substrates. They oxidize glucose both at C2 and C3 and upon prolonged reaction C2 and C3 double-oxidized glucose is obtained, confirming that the A. meleagris genes pdh2 (AY753308.1) and pdh3 (DQ117577.1) indeed encode CAZy class AA3_2 pyranose dehydrogenases. While reactivity with electron donor substrates was comparable for the three AmPDH isoforms, their kinetic properties differed significantly for the model electron acceptor substrates tested, a radical (the 2,2′-azino-bis[3-ethylbenzothiazoline-6-sulphonic acid] cation radical), a quinone (benzoquinone) and a complexed iron ion (the ferricenium ion). Thus, a possible explanation for this PDH multiplicity in A. meleagris could be that different isoforms react preferentially with structurally different electron acceptors in vivo.(VLID)192910
Study of Field-Induced Magnetic Order in Singlet-Ground-State Magnet CsFeCl
The field-induced magnetic order in the singlet-ground-state system
CsFeCl has been studied by measuring magnetization and neutron diffraction.
The field dependence of intensity for the neutron magnetic reflection has
clearly demonstrated that the field-induced ordered phase is described by the
order parameter . A condensate growth of magnons is investigated through
the temperature dependence of and , and this ordering is
discussed in the context of a magnon Bose-Einstein condensation. Development of
the coherent state and the static correlation length has been observed in the
incommensurate phase in the field region of , a satellite peak was found in coexistence with the commensurate
peak at the phase boundary around 10 T, which indicates that the tilt of the
c-axis would be less than in the whole experiments.Comment: 5 pages, 5 figure
Neutral currents and tests of three-neutrino unitarity in long-baseline experiments
We examine a strategy for using neutral current measurements in long-baseline
neutrino oscillation experiments to put limits on the existence of more than
three light, active neutrinos. We determine the relative contributions of
statistics, cross section uncertainties, event misidentification and other
systematic errors to the overall uncertainty of these measurements. As specific
case studies, we make simulations of beams and detectors that are like the K2K,
T2K, and MINOS experiments. We find that the neutral current cross section
uncertainty and contamination of the neutral current signal by charge current
events allow a sensitivity for determining the presence of sterile neutinos at
the 0.10--0.15 level in probablility.Comment: 24 pages, Latex2e, uses graphicx.sty, 2 postscript figures. Submitted
to the Neutrino Focus Issue of New Journal Physics at http://www.njp.or
Structural correlations in heterogeneous electron transfer at monolayer and multilayer graphene electrodes
As a new form of carbon, graphene is attracting intense interest as an electrode material with widespread applications. In the present study, the heterogeneous electron transfer (ET) activity of graphene is investigated using scanning electrochemical cell microscopy (SECCM), which allows electrochemical currents to be mapped at high spatial resolution across a surface for correlation with the corresponding structure and properties of the graphene surface. We establish that the rate of heterogeneous ET at graphene increases systematically with the number of graphene layers, and show that the stacking in multilayers also has a subtle influence on ET kinetics. © 2012 American Chemical Society
The effect of intervertebral cartilage on neutral posture and range of motion in the necks of sauropod dinosaurs
The necks of sauropod dinosaurs were a key factor in their evolution. The habitual posture and range of motion of these necks has been controversial, and computer-aided studies have argued for an obligatory sub-horizontal pose. However, such studies are compromised by their failure to take into account the important role of intervertebral cartilage. This cartilage takes very different forms in different animals. Mammals and crocodilians have intervertebral discs, while birds have synovial joints in their necks. The form and thickness of cartilage varies significantly even among closely related taxa. We cannot yet tell whether the neck joints of sauropods more closely resembled those of birds or mammals. Inspection of CT scans showed cartilage:bone ratios of 4.5% for Sauroposeidon and about 20% and 15% for two juvenile Apatosaurus individuals. In extant animals, this ratio varied from 2.59% for the rhea to 24% for a juvenile giraffe. It is not yet possible to disentangle ontogenetic and taxonomic signals, but mammal cartilage is generally three times as thick as that of birds. Our most detailed work, on a turkey, yielded a cartilage:bone ratio of 4.56%. Articular cartilage also added 11% to the length of the turkey's zygapophyseal facets. Simple image manipulation suggests that incorporating 4.56% of neck cartilage into an intervertebral joint of a turkey raises neutral posture by 15°. If this were also true of sauropods, the true neutral pose of the neck would be much higher than has been depicted. An additional 11% of zygapophyseal facet length translates to 11% more range of motion at each joint. More precise quantitative results must await detailed modelling. In summary, including cartilage in our models of sauropod necks shows that they were longer, more elevated and more flexible than previously recognised
Training of Instrumentalists and Development of New Technologies on SOFIA
This white paper is submitted to the Astronomy and Astrophysics 2010 Decadal
Survey (Astro2010)1 Committee on the State of the Profession to emphasize the
potential of the Stratospheric Observatory for Infrared Astronomy (SOFIA) to
contribute to the training of instrumentalists and observers, and to related
technology developments. This potential goes beyond the primary mission of
SOFIA, which is to carry out unique, high priority astronomical research.
SOFIA is a Boeing 747SP aircraft with a 2.5 meter telescope. It will enable
astronomical observations anywhere, any time, and at most wavelengths between
0.3 microns and 1.6 mm not accessible from ground-based observatories. These
attributes, accruing from the mobility and flight altitude of SOFIA, guarantee
a wealth of scientific return. Its instrument teams (nine in the first
generation) and guest investigators will do suborbital astronomy in a
shirt-sleeve environment. The project will invest $10M per year in science
instrument development over a lifetime of 20 years. This, frequent flight
opportunities, and operation that enables rapid changes of science instruments
and hands-on in-flight access to the instruments, assure a unique and extensive
potential - both for training young instrumentalists and for encouraging and
deploying nascent technologies. Novel instruments covering optical, infrared,
and submillimeter bands can be developed for and tested on SOFIA by their
developers (including apprentices) for their own observations and for those of
guest observers, to validate technologies and maximize observational
effectiveness.Comment: 10 pages, no figures, White Paper for Astro 2010 Survey Committee on
State of the Professio
Meta-analysis Reveals Genome-Wide Significance at 15q13 for Nonsyndromic Clefting of Both the Lip and the Palate, and Functional Analyses Implicate GREM1 As a Plausible Causative Gene
Nonsyndromic orofacial clefts are common birth defects with multifactorial etiology. The
most common type is cleft lip, which occurs with or without cleft palate (nsCLP and nsCLO,
respectively). Although genetic components play an important role in nsCLP, the genetic
factors that predispose to palate involvement are largely unknown. In this study, we carried
out a meta-analysis on genetic and clinical data from three large cohorts and identified
strong association between a region on chromosome 15q13 and nsCLP (P = 8.13×10−14 for
rs1258763; relative risk (RR): 1.46, 95% confidence interval (CI): 1.32–1.61)) but not
nsCLO (P = 0.27; RR: 1.09 (0.94–1.27)). The 5 kb region of strongest association maps
downstream of Gremlin-1 (GREM1), which encodes a secreted antagonist of the BMP4
pathway. We show during mouse embryogenesis, Grem1 is expressed in the developing lip
and soft palate but not in the hard palate. This is consistent with genotype-phenotype correlations
between rs1258763 and a specific nsCLP subphenotype, since a more than two-fold
increase in risk was observed in patients displaying clefts of both the lip and soft palate but
who had an intact hard palate (RR: 3.76, CI: 1.47–9.61, Pdiff<0.05). While we did not find lip
or palate defects in Grem1-deficient mice, wild type embryonic palatal shelves developed
divergent shapes when cultured in the presence of ectopic Grem1 protein (P = 0.0014). The
present study identified a non-coding region at 15q13 as the second, genome-wide significant
locus specific for nsCLP, after 13q31. Moreover, our data suggest that the closely
located GREM1 gene contributes to a rare clinical nsCLP entity. This entity specifically
involves abnormalities of the lip and soft palate, which develop at different time-points and
in separate anatomical regions.Clefts of the lip and palate are common birth defects, and require long-term multidisciplinary
management. Their etiology involves genetic factors and environmental influences
and/or a combination of both, however, these interactions are poorly defined. Moreover,
although clefts of the lip may or may not involve the palate, the determinants predisposing
to specific subphenotypes are largely unknown. Here we demonstrate that variations in
the non-coding region near the GREM1 gene show a highly significant association with a
particular phenotype in which cleft lip and cleft palate co-occ
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