81 research outputs found

    Long-term evolution of the coupled boundary layers (STRATUS) mooring recovery and deployment cruise report NOAA Research Vessel R H Brown • cruise RB-01-08 9 October - 25 October 2001

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    This report documents the work done on cruise RB-01-08 of the NOAA R/V Ron Brown. This was Leg 2 of R/V Ron Brown’s participation in Eastern Pacific Investigation of Climate (EPIC) 2001, a study of air-sea interaction, the atmosphere, and the upper ocean in the eastern tropical Pacific. The science party included groups from the Woods Hole Oceanographic Institution (WHOI), NOAA Environmental Technology Laboratory (ETL), the University of Washington (UW), the University of California, Santa Barbara (UCSB), and the University Nacional Autonoma de Mexico (UNAM). The work done by these groups is summarized in this report. In addition, the routine underway data collected while aboard R/V Ron Brown is also summarized here.Funding was provided by the National Oceanic and Atmospheric Administration under Grant Numbers NA96GPO429 and NA17RJ1223

    A search for neutrino emission from the Fermi bubbles with the ANTARES telescope

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    Analysis of the Fermi-LAT data has revealed two extended structures above and below the Galactic Centre emitting gamma rays with a hard spectrum, the so-called Fermi bubbles. Hadronic models attempting to explain the origin of the Fermi bubbles predict the emission of high-energy neutrinos and gamma rays with similar fluxes. The ANTARES detector, a neutrino telescope located in the Mediterranean Sea, has a good visibility to the Fermi bubble regions. Using data collected from 2008 to 2011 no statistically significant excess of events is observed and therefore upper limits on the neutrino flux in TeV range from the Fermi bubbles are derived for various assumed energy cutoffs of the source

    Z-disc protein CHAPb induces cardiomyopathy and contractile dysfunction in the postnatal heart

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    The Z-disc is a crucial structure of the sarcomere and is implicated in mechanosensation/transduction. Dysregulation of Z-disc proteins often result in cardiomyopathy. We have previously shown that the Z-disc protein Cytoskeletal Heart-enriched Actin-associated Protein (CHAP) is essential for cardiac and skeletal muscle development. Furthermore, the CHAP gene has been associated with atrial fibrillation in humans. Here, we studied the misregulated expression of CHAP isoforms in heart disease. Mice that underwent transverse aortic constriction and calcineurin transgenic (Tg) mice, both models of experimental heart failure, displayed a significant increase in cardiac expression of fetal isoform CHAPb. To investigate whether increased expression of CHAPb postnatally is sufficient to induce cardiomyopathy, we generated CHAPb Tg mice under the control of the cardiac-specific αMHC promoter. CHAPb Tg mice displayed cardiac hypertrophy, interstitial fibrosis and enlargement of the left atrium at three months, which was more pronounced at the age of six months. Hypertrophy and fibrosis were confirmed by evidence of activation of the hypertrophic gene program (Nppa, Nppb, Myh7) and increased collagen expression, respectively. Connexin40 and 43 were downregulated in the left atrium, which was associated with delayed atrioventricular conduction. Tg hearts displayed both systolic and diastolic dysfunction partly caused by impaired sarcomere function evident from a reduced force generating capacity of single cardiomyocytes. This co-incided with activation of the actin signalling pathway leading to the formation of stress fibers. This study demonstrated that the fetal isoform CHAPb initiates progression towards cardiac hypertrophy, which is accompanied by delayed atrioventricular conduction and diastolic dysfunction. Moreover, CHAP may be a novel therapeutic target or candidate gene for screening in cardiomyopathies and atrial fibrillatio

    Multiple distinct coiled-coils are involved in dynamin self-assembly

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    Dynamin, a 100-kDa GTPase, has been implicated to be involved in synaptic vesicle recycling, receptor-mediated endocytosis, and other membrane sorting processes. Dynamin self-assembles into helical collars around the necks of coated pits and other membrane invaginations and mediates membrane scission. In vitro, dynamin has been reported to exist as dimers, tetramers, ring-shaped oligomers, and helical polymers. In this study we sought to define self-assembly regions in dynamin. Deletion of two closely spaced sequences near the dynamin-1 C terminus abolished self-association as assayed by co-immunoprecipitation and the yeast interaction trap, and reduced the sedimentation coefficient from 7.5 to 4.5 S. Circular dichroism spectroscopy and equilibrium ultracentrifugation of synthetic peptides revealed coiled-coil formation within the C-terminal assembly domain and at a third, centrally located site. Two of the peptides formed tetramers, supporting a role for each in the monomer-tetramer transition and providing novel insight into the organization of the tetramer. Partial deletions of the C-terminal assembly domain reversed the dominant inhibition of endocytosis by dynamin-1 GTPase mutants. Self-association was also observed between different dynamin isoforms. Taken altogether, our results reveal two distinct coiled-coil-containing assembly domains that can recognize other dynamin isoforms and mediate endocytic inhibition. In addition, our data strongly suggests a parallel model for dynamin subunit self-association
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