bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bimolecular Complementation of Paramyxovirus Fusion and Hemagglutinin-Neuraminidase Proteins Enhances Fusion: Implications for the Mechanism of Fusion Triggering
Authors: Connolly Sarah A. , Leser George P. , Jardetzky Theodore S. , Lamb Robert A. 
Published: August 2009

ABSTRACT
For paramyxoviruses, entry requires a receptor-binding protein (hemagglutinin-neuraminidase [HN], H, or G) and a fusion protein (F). Like other class I viral fusion proteins, F is expressed as a prefusion metastable protein that undergoes a refolding event to induce fusion. HN binding to its receptor triggers F refolding by an unknown mechanism. HN may serve as a clamp that stabilizes F in its prefusion state until HN binds the target cell (the “clamp model”). Alternatively, HN itself may undergo a conformational change after receptor binding that destabilizes F and causes F to trigger (the “provocateur model”). To examine F-HN interactions by bimolecular fluorescence complementation (BiFC), the cytoplasmic tails of parainfluenza virus 5 (PIV5) F and HN were fused to complementary fragments of yellow fluorescent protein (YFP). Coexpression of the BiFC constructs resulted in fluorescence; however, coexpression with unrelated BiFC constructs also produced fluorescence. The affinity of the two halves of YFP presumably superseded the F-HN interaction. Unexpectedly, coexpression of the BiFC F and HN constructs greatly enhanced fusion in multiple cell types. We hypothesize that the increase in fusion occurs because the BiFC tags bring F and HN together more frequently than occurs in a wild-type (wt) scenario. This implies that normally much of wt F is not associated with wt HN, in conflict with the clamp model for activation. Correspondingly, we show that wt PIV5 fusion occurs in an HN concentration-dependent manner. Also inconsistent with the clamp model are the findings that BiFC F does not adopt a postfusion conformation when expressed in the absence of HN and that HN coexpression does not provide resistance to the heat-induced triggering of F. In support of a provocateur model of F activation, we demonstrate by analysis of the morphology of soluble F trimers that the hyperfusogenic mutation S443P has a destabilizing effect on F.
Foot-and-Mouth Disease Virus Assembly: Processing of Recombinant Capsid Precursor by Exogenous Protease Induces Self-Assembly of Pentamers In Vitro in a Myristoylation-Dependent Manner
Authors: Goodwin Stewart , Tuthill Tobias J. , Arias Armando , Killington Richard A. , Rowlands David J. 
Published: August 2009

ABSTRACTThe assembly of foot-and-mouth disease virus (FMDV) particles is poorly understood. In addition, there are important differences in the antigenic and receptor binding properties of virus assembly and dissociation intermediates, and these also remain unexplained. We have established an experimental model in which the antigenicity, receptor binding characteristics, and in vitro assembly of capsid precursor can be studied entirely from purified components. Recombinant capsid precursor protein (P1 region) was expressed inEscherichia colias myristoylated or unmyristoylated protein. The protein sedimented in sucrose gradients at 5S and reacted with monoclonal antibodies which recognize conformational or linear antigen determinants on the virion surface. In addition, it bound the integrin αvβ6, a cellular receptor for FMDV, indicating that unprocessed recombinant capsid precursor is both structurally and antigenically similar to native virus capsid. These characteristics were not dependent on the presence of 2A at the C terminus but were altered by N-terminal myristoylation and in mutant precursors which lacked VP4. Proteolytic processing of myristoylated precursor by recombinant FMDV 3Cproin vitro induced a shift in sedimentation from 5S to 12S, indicating assembly into pentameric capsid subunits. Nonmyristoylated precursor still assembled into higher-order structures after processing with 3Cpro, but these particles sedimented in sucrose gradients at approximately 17S. In contrast, mutant precursors lacking VP4 were antigenically distinct, were unable to form pentamers, and had reduced capacity for binding integrin receptor. These studies demonstrate the utility of recombinant capsid precursor protein for investigating the initial stages of assembly of FMDV and other picornaviruses.
Analysis of Protein Levels of 24 Cytokines in Scrapie Agent-Infected Brain and Glial Cell Cultures from Mice Differing in Prion Protein Expression Levels
Authors: Tribouillard-Tanvier Déborah , Striebel James F. , Peterson Karin E. , Chesebro Bruce 
Published: August 2009

ABSTRACTActivation of microglia and astroglia is seen in many neurodegenerative diseases including prion diseases. Activated glial cells produce cytokines as a protective response against certain pathogens and as part of the host inflammatory response to brain damage. In addition, cytokines might also exacerbate tissue damage initiated by other processes. In the present work using multiplex assays to analyze protein levels of 24 cytokines in scrapie agent-infected C57BL/10 mouse brains, we observed elevation of CCL2, CCL5, CXCL1, CXCL10, granulocyte-macrophage colony-stimulating factor (GM-CSF), gamma interferon (IFN-γ), interleukin 1α (IL-1α), IL-1β, IL-6, and IL-12p40. Scrapie agent-infected wild-type mice and transgenic mice expressing anchorless prion protein (PrP) had similar cytokine responses in spite of extensive differences in neuropathology. Therefore, these responses may be primarily a reaction to brain damage induced by prion infection rather than specific inducers of a particular type of pathology. To study the roles of astroglia and microglia in these cytokine responses, primary glial cultures were exposed to scrapie agent-infected brain homogenates. Microglia produced only IL-12p40 and CXCL10, whereas astroglia produced these cytokines plus CCL2, CCL3, CCL5, CXCL1, G-CSF, IL-1β, IL-6, IL-12p70, and IL-13. Glial cytokine responses from wild-type mice and transgenic mice expressing anchorless PrP differed only slightly, but glia from PrP-null mice produced only IL-12p40, indicating that PrP expression was required for scrapie agent induction of other cytokines detected. The difference in cytokine response between microglia and astroglia correlated with 20-fold-higher levels of PrP expression in astroglia versus microglia, suggesting that high-level PrP expression on astroglia might be important for induction of certain cytokines.
Identification of RNA Helicase A as a New Host Factor in the Replication Cycle of Foot-and-Mouth Disease Virus
Authors: Lawrence Paul , Rieder Elizabeth 
Published: August 2009

ABSTRACTFoot-and-mouth disease virus (FMDV), as with other RNA viruses, recruits various host cell factors to assist in the translation and replication of the virus genome. In this study, we investigated the role of RNA helicase A (RHA) in the life cycle of FMDV. Immunofluorescent microscopy (IFM) showed a change in the subcellular distribution of RHA from the nucleus to the cytoplasm in FMDV-infected cells as infection progressed. Unlike nuclear RHA, the RHA detected in the cytoplasm reacted with an antibody that recognizes only the nonmethylated form of RHA. In contrast to alterations in the subcellular distribution of nuclear factors observed during infection with the related cardioviruses, cytoplasmic accumulation of RHA did not require the activity of the FMDV leader protein. Using IFM, we have found cytoplasmic RHA in proximity to the viral 2C and 3A proteins, which promotes the assembly of the replication complexes, as well as cellular poly(A) binding protein (PABP). Coimmunoprecipitation assays confirmed that these proteins are complexed with RHA. We have also identified a novel interaction between RHA and the S fragment in the FMDV 5′ nontranslated region. Moreover, a reduction in the expression of RHA, using RHA-specific small interfering RNA constructs, inhibited FMDV replication. These results indicate that RHA plays an essential role in the replication of FMDV and potentially other picornaviruses through ribonucleoprotein complex formation at the 5′ end of the genome and by interactions with 2C, 3A, and PABP.
In situ high-pressure study of ammonia borane by Raman and IR spectroscopy
Authors: Xie Shuntai , Song Yang , Liu Zhenxian 
Published: August 2009

Pressure-induced structural transformations of the ammonia borane complex (NH3·BH3) were investigated in diamond anvil cells by Raman spectroscopy and synchrotron IR spectroscopy up to 14 GPa at room temperature. Starting with a disordered tetragonal structure, NH3·BH3 is found to undergo several transformations upon compression as monitored by in situ Raman measurements. These transformations are indicated by the sequential changes of characteristic Raman modes as well as by the pressure dependence of these modes. Synchrotron IR absorption spectroscopy provided supplementary and consistent information about the structural evolution of NH3·BH3 under compression. Decompression measurements on NH3·BH3 suggest the pressure-induced transformations are reversible in the entire pressure region. The combined Raman and IR data allowed analysis of possible high-pressure structures of NH3·BH3. Our study significantly complements previous high-pressure Raman studies by providing new information on the structures and stabilities of NH3·BH3.
Investigation of the Variability of Cloud Condensation Nuclei Concentrations at the Surface in Western North Dakota
Authors: Detwiler Andrew , Langerud Darin , Depue Tracy 
Published: August 2009

Abstract
Daily observations of cloud condensation nuclei (CCN) were made for three summer months in 2005 at a site in rural western North Dakota. The goal was to define the natural background CCN population characteristics and to lay the groundwork for investigating the potential impact of intentionally modifying clouds in this region using hygroscopic cloud-seeding techniques. Concentrations of CCN active at ∼0.5% supersaturation, averaged over several midday hours on each day, ranged from less than 200 to more than 1700 cm−3. This is similar to variability in CCN concentrations that have been observed in past studies in other rural areas of the central and northern high plains of the United States. At this site, only 2 out of 17 days with active convection at that site were characterized by concentrations of less than 300 cm−3 active at 0.5% supersaturation, indicating that the region is characterized by typically continental CCN populations on most convective days. Operational seeding might be more effectively conducted if CCN population characteristics could be forecast based on source regions for air forecast to arrive in a particular region on a particular day. However, back-trajectory calculations were found to have limited use for predicting CCN concentrations based on prior history of the air arriving at this observation site during this period.
Simulations of Polarimetric Radar Signatures of a Supercell Storm Using a Two-Moment Bulk Microphysics Scheme
Authors: Jung Youngsun , Xue Ming , Zhang Guifu 
Published: August 2009

Abstract
A new general polarimetric radar simulator for nonhydrostatic numerical weather prediction (NWP) models has been developed based on rigorous scattering calculations using the T-matrix method for reflectivity, differential reflectivity, specific differential phase, and copolar cross-correlation coefficient. A continuous melting process accounts for the entire spectrum of varying density and dielectric constants. This simulator is able to simulate polarimetric radar measurements at weather radar frequency bands and can take as input the prognostic variables of high-resolution NWP model simulations using one-, two-, and three-moment microphysics schemes. The simulator was applied at 10.7-cm wavelength to a model-simulated supercell storm using a double-moment (two moment) bulk microphysics scheme to examine its ability to simulate polarimetric signatures reported in observational studies. The simulated fields exhibited realistic polarimetric signatures that include ZDR and KDP columns, ZDR arc, midlevel ZDR and ρhυ rings, hail signature, and KDP foot in terms of their general location, shape, and strength. The authors compared the simulation with one employing a single-moment (SM) microphysics scheme and found that certain signatures, such as ZDR arc, midlevel ZDR, and ρhυ rings, cannot be reproduced with the latter. It is believed to be primarily caused by the limitation of the SM scheme in simulating the shift of the particle size distribution toward larger/smaller diameters, independent of mixing ratio. These results suggest that two- or higher-moment microphysics schemes should be used to adequately describe certain important microphysical processes. They also demonstrate the utility of a well-designed radar simulator for validating numerical models. In addition, the simulator can also serve as a training tool for forecasters to recognize polarimetric signatures that can be reproduced by advanced NWP models.
Mesoscale Eddy–Internal Wave Coupling. Part II: Energetics and Results from PolyMode
Authors: Polzin Kurt L. 
Published: August 2009

Abstract
The issue of internal wave–mesoscale eddy interactions is revisited. Previous observational work identified the mesoscale eddy field as a possible source of internal wave energy. Characterization of the coupling as a viscous process provides a smaller horizontal transfer coefficient than previously obtained, with vh ≅ 50 m2 s−1 in contrast to νh ≅ 200–400 m2 s−1, and a vertical transfer coefficient bounded away from zero, with νυ + ( f 2/N 2)Kh ≅ 2.5 ± 0.3 × 10−3 m2 s−1 in contrast to νυ + ( f 2/N 2)Kh = 0 ± 2 × 10−2 m2 s−1. Current meter data from the Local Dynamics Experiment of the PolyMode field program indicate mesoscale eddy–internal wave coupling through horizontal interactions (i) is a significant sink of eddy energy and (ii) plays an O(1) role in the energy budget of the internal wave field.
Gas Bubbles as Oceanographic Tracers
Authors: Baschek Burkard , Farmer David M. 
Published: August 2009

Abstract
Air bubbles can be used as oceanographic tracers that indicate the strength of a downwelling current by which they are subducted. In a tidal front in the Fraser Estuary, British Columbia, Canada, vertical currents of up to 0.70 m s−1 subduct bubbles to depths of more than 160 m. Echo sounder measurements are compared with simultaneous ADCP current measurements and are interpreted with a bubble model by S. A. Thorpe, yielding an estimate of the vertical current that carries the bubbles to the depth of measurement.
Multi-Family Group Intervention in a Programme for Patients With First-Episode Psychosis: a Brazilian Experience
Authors: Fabri Cabral Rita Regina , Chaves Ana Cristina 
Published: August 2009

Background: Patients’ relatives are considered crucial for treatment and recovery in psychosis but family intervention studies have shown contradictory results in firstepisode psychosis. The aims of this study were to survey caregivers’ satisfaction with the multi-family intervention delivered by our programme and to verify if knowledge acquisition about illness and treatment provided by the family intervention was considered enough and understandable. Methods: Sixty five family members of 46 first-episode patients were invited to answer a satisfaction questionnaire about the intervention. Results: Forty individuals returned the questionnaire: 31 women (77.5%) and nine men (22.5%). Most (82.5%) had daily contact with the patient and 19 (47.5%) were mothers. Regarding knowledge acquisition, approximately one third did not improve their understanding of the illness. Nonetheless, 90% of the participants believed the meetings helped them to cope with their ill relative and 95% approved the multi-family format. Conclusions: Non-specific aspects of the intervention were seen as the most useful part of the programme. An important target of treatment would be to improve the way in which the specific psychoeducational components are delivered to individuals with low formal education.
Angiotensin II type 1 receptor gene polymorphism in myocardial infarction patients
Authors: Bhoomi Reddy Pullareddy  , Baddela Muni Venkata Srikanth Babu  , Kolla Venkata Karunakar  , Yasovanthi Jeedigunta , Potham Sampath Kumar  , Sharath Annam , Jyothy Akka 
Published: August 2009

Introduction. Acute myocardial infarction is commonly known as heart attack. It is a multifactorial disease influenced by environmental and genetic factors.The objective of the present study was to investigate the association of the angiotensin II type 1 receptor gene A/C polymorphism in South Indian myocardial infarction patients.Subjects and methods. The present study included a total number of 221 subjects (107 myocardial infarction patients and 114 age- and sex-matched controls). Demographic and clinical characteristics were collected. Lipid profiles were estimated. DNA was isolated and the angiotensin II type 1 receptor gene A/C polymorphism was determined by polymerase chain reaction.Results. Comparison of the lipid profiles between patients and controls showed that patients had statistically highly significant values (p=0.0001).The CC genotype of the angiotensin II type 1 receptor was not associated with myocardial infarction patients when compared to controls. CC vs. AA was χ2= 2.08, odds ratio 2.30, 95% confidence interval 0.72 — 7.23, and p value was 0.14.Conclusion. The angiotensin II type 1 receptor CC genotype is not a risk factor for myocardial infarction in patients in a South Indian population.
Aldosterone-induced endothelial dysfunction of rat aorta: role of poly(ADP-ribose) activation
Authors: Tasatargil Arda , Tekcan Merih , Celik-Ozenci Ciler , Ece Gungor Nazli , Dalkiran Bedriniam 
Published: August 2009

Introduction. The aim of this study was to investigate whether activation of the nuclear enzyme poly(ADP-ribose) polymerase (PARP) contributes to the development of aldosterone-induced endothelial dysfunction and treatment with the potent PARP inhibitor 1,5-isoquinolinediol (3 mg/kg/day, i.p.) could prevent endothelial dysfunction caused by aldosterone. Methods. Infusion of subpressor doses of aldosterone with subcutaneously implanted mini-osmotic pumps (0.05 mg/kg/day) to rats for 21 days induced the development of endothelial dysfunction. In order to evaluate endothelial function, isometric tension studies were performed in response to acetylcholine and sodium nitroprusside.Additionally, PAR (the end product of activated PARP) and PARP-1 expressions in the endothelium of thoracic aortas were evaluated by immunohistochemistry. Results. There was a significant loss of endothelium-dependent vasodilatation in response to acetylcholine in aldosterone-infused rats. In animals treated with 1,5-isoquinolinediol, the effect of aldosterone on vascular responsiveness was less than the untreated groups. Immunohistochemical studies demonstrated that aldosterone administration increased PAR and PARP-1 expressions in the endothelium of thoracic aortas, whereas PARP inhibition decreased their expressions to control levels. Conclusion. Our results indicate that PARP activation in the vascular system may be a contributory factor to the impaired endothelial function associated with aldosterone administration.
Effect of the nonpeptide thrombopoietin receptor agonist Eltrombopag on bone marrow cells from patients with acute myeloid leukemia and myelodysplastic syndrome
Authors: Will Britta , Kawahara Masahiro , Luciano Julia P. , Bruns Ingmar , Parekh Samir , Erickson-Miller Connie L. , Aivado Manuel A. , Verma Amit , Steidl Ulrich 
Published: August 2009

Abstract
Thrombocytopenia is a frequent symptom and clinical challenge in patients with myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). Eltrombopag is a small molecule thrombopoietin receptor agonist that might be a new option to treat thrombocytopenia in these diseases, provided that it does not stimulate malignant hematopoiesis. In this work, we studied the effects of Eltrombopag on proliferation, apoptosis, differentiation, colony formation, and malignant self-renewal of bone marrow mononuclear cells of patients with AML and MDS. Malignant bone marrow mononuclear cells did not show increased proliferation, or increased clonogenic capacity at concentrations of Eltrombopag ranging from 0.1 to 30 μg/mL. On the contrary, we observed a moderate, statistically nonsignificant (P = .18), decrease of numbers of malignant cells (mean, 56%; SD, 28%). Eltrombopag neither led to increased 5-bromo-2-deoxyuridine incorporation, decreased apoptosis, an increase of malignant self-renewal, nor enhanced in vivo engraftment in xenotransplantations. Furthermore, we found that Eltrombopag was capable of increasing megakaryocytic differentiation and formation of normal megakaryocytic colonies in patients with AML and MDS. These results provide a preclinical rationale for further testing of Eltrombopag for treatment of thrombocytopenia in AML and MDS.
Detecting disease-associated genotype patterns
Authors: Long Quan , Zhang Qingrun , Ott Jurg 
Published: August 2009

Abstract

Background
In addition to single-locus (main) effects of disease variants, there is a growing consensus that gene-gene and gene-environment interactions may play important roles in disease etiology. However, for the very large numbers of genetic markers currently in use, it has proven difficult to develop suitable and efficient approaches for detecting effects other than main effects due to single variants.

Results
We developed a method for jointly detecting disease-causing single-locus effects and gene-gene interactions. Our method is based on finding differences of genotype pattern frequencies between case and control individuals. Those single-nucleotide polymorphism markers with largest single-locus association test statistics are included in a pattern. For a logistic regression model comprising three disease variants exerting main and epistatic interaction effects, we demonstrate that our method is vastly superior to the traditional approach of looking for single-locus effects. In addition, our method is suitable for estimating the number of disease variants in a dataset. We successfully apply our approach to data on Parkinson Disease and heroin addiction.

Conclusion
Our approach is suitable and powerful for detecting disease susceptibility variants with potentially small main effects and strong interaction effects. It can be applied to large numbers of genetic markers.