208 research outputs found
Recommended from our members
Novel integrin endocytosis motif
Integrins are heterodimeric cell-surface adhesion molecules comprising one of 18 possible α-chains and one of eight possible ÎČ-chains. They control a range of cell functions in a matrix- and ligand-specific manner. Integrins can be internalized by clathrin-mediated endocytosis (CME) through ÎČ subunit-based motifs found in all integrin heterodimers. However, whether specific integrin heterodimers can be selectively endocytosed was unknown. Here, we found that a subset of α subunits contain an evolutionarily conserved and functional YxxΊ motif directing integrins to selective internalization by the most abundant endocytic clathrin adaptor, AP2. We determined the structure of the human integrin α4-tail motif in complex with the AP2 C-ÎŒ2 subunit and confirmed the interaction by isothermal titration calorimetry. Mutagenesis of the motif impaired selective heterodimer endocytosis and attenuated integrin-mediated cell migration. We propose that integrins evolved to enable selective integrin-receptor turnover in response to changing matrix conditions.We gratefully acknowledge the following funding sources: N.d.F. FinPharma Doctoral Program, Instrumentarium Foundation, Orion Research Foundation, Liv och Halsa foundation, Finsk-Norska Medicinska Stiftelsen and the Magnus Ehrnrooth Foundation; J.I. Academy of Finland CoE, European Research Council Consolidator Grant, the Sigrid Juselius Foundation, The Finnish Heart Foundation and Finnish Cancer Organizations. DJO, AGW and TW are funded by Wellcome Trust fellowship 090909 (DJO).This is the author accepted manuscript. The final version is available from Nature Publishing Group via http://dx.doi.org/10.1038/nsmb.3161
Transcriptional response of the extremophile red alga Cyanidioschyzon merolae to changes in CO2 concentrations
Rademacher N, Wrobel TJ, Rossoni AW, et al. Transcriptional response of the extremophile red alga Cyanidioschyzon merolae to changes in CO2 concentrations. Journal of Plant Physiology. 2017;217:49-56.Cyanidioschyzon merolae (C. merolae) is an acidophilic red alga growing in a naturally low carbon dioxide (CO2) environment. Although it uses a ribulose 1,5-bisphosphate carboxylase/oxygenase with high affinity for CO2, the survival of C. merolae relies on functional photorespiratory metabolism. In this study, we quantified the transcriptomic response of C. merolae to changes in CO2 conditions. We found distinct changes upon shifts between CO2 conditions, such as a concerted up-regulation of photorespiratory genes and responses to carbon starvation. We used the transcriptome data set to explore a hypothetical CO2 concentrating mechanism in C. merolae, based on the assumption that photorespiratory genes and possible candidate genes involved in a CO2 concentrating mechanism are co-expressed. A putative bicarbonate transport protein and two a-carbonic anhydrases were identified, which showed enhanced transcript levels under reduced CO2 conditions. Genes encoding enzymes of a PEPCK-type C-4 pathway were co-regulated with the photorespiratory gene cluster. We propose a model of a hypothetical low CO2 compensation mechanism in C. merolae integrating these low CO2-inducible components
Geovisual analytics for spatial decision support: Setting the research agenda
This article summarizes the results of the workshop on Visualization, Analytics & Spatial Decision Support, which took place at the GIScience conference in September 2006. The discussions at the workshop and analysis of the state of the art have revealed a need in concerted crossâdisciplinary efforts to achieve substantial progress in supporting spaceârelated decision making. The size and complexity of realâlife problems together with their illâdefined nature call for a true synergy between the power of computational techniques and the human capabilities to analyze, envision, reason, and deliberate. Existing methods and tools are yet far from enabling this synergy. Appropriate methods can only appear as a result of a focused research based on the achievements in the fields of geovisualization and information visualization, humanâcomputer interaction, geographic information science, operations research, data mining and machine learning, decision science, cognitive science, and other disciplines. The name âGeovisual Analytics for Spatial Decision Supportâ suggested for this new research direction emphasizes the importance of visualization and interactive visual interfaces and the link with the emerging research discipline of Visual Analytics. This article, as well as the whole special issue, is meant to attract the attention of scientists with relevant expertise and interests to the major challenges requiring multidisciplinary efforts and to promote the establishment of a dedicated research community where an appropriate range of competences is combined with an appropriate breadth of thinking
SDSS J1254+0846: A Binary Quasar Caught in the Act of Merging
We present the first luminous, spatially resolved binary quasar that clearly
inhabits an ongoing galaxy merger. SDSS J125455.09+084653.9 and SDSS
J125454.87+084652.1 (SDSS J1254+0846 hereafter) are two luminous z=0.44 radio
quiet quasars, with a radial velocity difference of just 215 km/s, separated on
the sky by 21 kpc in a disturbed host galaxy merger showing obvious tidal
tails. The pair was targeted as part of a complete sample of binary quasar
candidates with small transverse separations drawn from SDSS DR6 photometry. We
present follow-up optical imaging which shows broad, symmetrical tidal arm
features spanning some 75 kpc at the quasars' redshift. Numerical modeling
suggests that the system consists of two massive disk galaxies prograde to
their mutual orbit, caught during the first passage of an active merger. This
demonstrates rapid black hole growth during the early stages of a merger
between galaxies with pre-existing bulges. Neither of the two luminous nuclei
show significant instrinsic absorption by gas or dust in our optical or X-ray
observations, illustrating that not all merging quasars will be in an obscured,
ultraluminous phase. We find that the Eddington ratio for the fainter component
B is rather normal, while for the A component L/LEdd is quite (>3sigma) high
compared to quasars of similar luminosity and redshift, possibly evidence for
strong merger-triggered accretion. More such mergers should be identifiable at
higher redshifts using binary quasars as tracers.Comment: 15 pages, 5 figures, accepted to the Astrophysical Journal for the
February 2010 - 20 v710 issue. Latest version corrects author lis
Elliptical Galaxies and Bulges of Disk Galaxies: Summary of Progress and Outstanding Issues
This is the summary chapter of a review book on galaxy bulges. Bulge
properties and formation histories are more varied than those of ellipticals. I
emphasize two advances: 1 - "Classical bulges" are observationally
indistinguishable from ellipticals, and like them, are thought to form by major
galaxy mergers. "Disky pseudobulges" are diskier and more actively star-forming
(except in S0s) than are ellipticals. Theys are products of the slow
("secular") evolution of galaxy disks: bars and other nonaxisymmetries move
disk gas toward the center, where it starbursts and builds relatively flat,
rapidly rotating components. This secular evolution is a new area of galaxy
evolution work that complements hierarchical clustering. 2 - Disks of
high-redshift galaxies are unstable to the formation of mass clumps that sink
to the center and merge - an alternative channel for the formation of classical
bulges. I review successes and unsolved problems in the formation of
bulges+ellipticals and their coevolution (or not) with supermassive black
holes. I present an observer's perspective on simulations of dark matter galaxy
formation including baryons. I review how our picture of the quenching of star
formation is becoming general and secure at redshifts z < 1. The biggest
challenge is to produce realistic bulges+ellipticals and disks that overlap
over a factor of 10**3 in mass but that differ from each other as observed over
that whole range. Second, how does hierarchical clustering make so many giant,
bulgeless galaxies in field but not cluster environments? I argue that we rely
too much on AGN and star-formation feedback to solve these challenges.Comment: 46 pages, 10 postscript figures, accepted for publication in Galactic
Bulges, ed. E. Laurikainen, R. F. Peletier, & D. A. Gadotti (New York:
Springer), in press (2015
Insights from the STICH trial: Change in left ventricular size after coronary artery bypass grafting with and without surgical ventricular reconstruction
ObjectiveThe present analysis of the Surgical Treatment for Ischemic Heart Failure randomized trial data examined the left ventricular volumes at baseline and 4 months after surgery to determine whether any magnitude of postoperative reduction in end-systolic volume affected survival after coronary artery bypass grafting alone compared with bypass grafting plus surgical ventricular reconstruction.MethodsOf the 1000 patients randomized, 555 underwent an operation and had a paired imaging assessment with the same modality at baseline and 4 months postoperatively. Of the remaining 455 patients, 424 either died before the 4-month study or did not have paired imaging tests and were excluded, and 21 were not considered because they had died before surgery or did not receive surgery.ResultsSurgical ventricular reconstruction resulted in improved survival compared with coronary artery bypass grafting alone when the postoperative end-systolic volume index was 70 mL/m2 or less. However, the opposite was true for patients achieving a postoperative volume index greater than 70 mL/m2. A reduction in the end-systolic volume index of 30% or more compared with baseline was an infrequent event in both treatment groups and did not produce a statistically significant survival benefit with ventricular reconstruction.ConclusionsIn patients undergoing coronary artery bypass grafting plus surgical ventricular reconstruction, a survival benefit was realized compared with bypass alone, with the achievement of a postoperative end-systolic volume index of 70 mL/m2 or less. Extensive ventricular remodeling at baseline might limit the ability of ventricular reconstruction to achieve a sufficient reduction in volume and clinical benefit
Modern microwave methods in solid state inorganic materials chemistry: from fundamentals to manufacturing
No abstract available
- âŠ