bluuebunny/crossref_metadata_2025_split huggingface dataset:
Contribution of Virus-Like Particles to the Immunogenicity of Human Immunodeficiency Virus Type 1 Gag-Derived Vaccines in Mice
Authors: Wong S. B. Justin , Siliciano Robert F. 
Published: January 2005

ABSTRACTThe human immunodeficiency virus type 1 (HIV-1) Gag protein is a major target antigen for cytotoxic-T-lymphocyte-based vaccine strategies because of its high level of conservation. The murine model has been used extensively to evaluate potential HIV-1 vaccines. However, the biology of HIV-1 Gag is somewhat different in human and murine tissues. The ability of HIV-1 Gag to form virus-like particles (VLPs) in human cells is severely curtailed in murine cells. Hence, it is not known whether immunizing mice with expression vectors encoding HIV-1 Gag provides an accurate assessment of the immunogenicity of these candidate vaccines in primates. In this report, we made use of a chimeric Moloney murine leukemia virus (MMLV)-HIV-1 Gag in which the p17 matrix domain of HIV-1 was replaced with the p15 matrix and p12 domains from MMLV. Murine cells expressing this construct released significant amounts of VLPs. The construct preservedH-2d-restricted antigenic determinants in the remaining portion of HIV-1 Gag, allowing immunogenicity studies to be performed with mice. We demonstrated that immunizing mice with plasmid DNA or adenoviral vectors encoding this chimeric Gag did not significantly increase the HIV-1 Gag-specific cellular or humoral immune response when compared to immunization with a myristoylation-incompetent version of the construct. Thus, the release of VLPs formed in vivo may not play a major role in the immunogenicity of vectors expressing HIV-1 Gag constructs.
Characterization of gp120 and Its Single-Chain Derivatives, gp120-CD4D12and gp120-M9: Implications for Targeting the CD4iEpitope in Human Immunodeficiency Virus Vaccine Design
Authors: Varadarajan Raghavan , Sharma Deepak , Chakraborty Kausik , Patel Mayuri , Citron Michael , Sinha Prem , Yadav Ramkishor , Rashid Umar , Kennedy Sarah , Eckert Debra , Geleziunas Romas , Bramhill David , Schleif William , Liang Xiaoping , Shiver John 
Published: January 2005

ABSTRACTSingle-chain derivatives of JRFL gp120 linked to the first two domains of human CD4 (gp120-CD4D12) or to the CD4 miniprotein analog CD4M9 (gp120-M9), have been constructed. Biacore studies revealed that gp120-CD4D12and gp120-M9 bound to antibody 17b with dissociation constants of 0.8 and 25 nM, respectively, at pH 7.0, while gp120 alone did not bind. The binding of gp120-CD4D12to 17b is not affected by the addition of excess soluble CD4D12, while the binding of gp120-M9 is enhanced. This finding indicates that the M9 component of the single chain interacts relatively weakly with gp120 and can be displaced by soluble CD4D12. Immunogenicity studies of gp120, gp120-CD4D12, and gp120-M9 were carried out with guinea pigs. All three molecules were highly immunogenic. The resulting antisera were examined for neutralizing activities against various human immunodeficiency virus type 1 isolates. Broadly neutralizing activity was observed only with sera generated against gp120-CD4D12. These antisera were depleted of anti-CD4D12antibodies by being passed over a column containing immobilized CD4D12. The depleted sera showed a loss of broadly neutralizing activity. Sera that were affinity purified over a column containing immobilized gp120-M9 also lacked such neutralizing activity. This finding suggests that the broadly neutralizing response observed is exclusively due to anti-CD4 antibodies. Competition experiments showed that only antisera generated against gp120-CD4D12competed with the CD4iantibody 17b and that this activity was not affected by depletion of anti-CD4 antibodies. The data indicate that although antibodies targeting the CD4iepitope were generated by the gp120-CD4D12immunogen, these antibodies were nonneutralizing.
The Epstein-Barr Virus-Encoded LMP2A and LMP2B Proteins Promote Epithelial Cell Spreading and Motility
Authors: Allen Michael D. , Young Lawrence S. , Dawson Christopher W. 
Published: January 2005

ABSTRACT
The frequent expression of latent membrane proteins LMP2A and LMP2B in Epstein Barr virus (EBV)-associated tumors suggests that these proteins play a role in EBV-induced epithelial cell growth transformation. Expression of LMP2A and LMP2B had no effect on the morphology of squamous epithelial cells in monolayer culture, but their expression was associated with an increased capacity to spread and migrate on extracellular matrix. Although the mechanisms by which LMP2A and LMP2B promote cell spreading and motility are unclear, the use of selective pharmacological inhibitors has established a role for tyrosine kinases in this phenotype but ruled out contributions of phosphatidylinositol 3-kinase, extracellular signal-regulated kinase/mitogen-activated protein kinase, and protein kinase C. The ability of LMP2B to induce a phenotype that is virtually indistinguishable from that of LMP2A suggests that regions of the LMP2 protein in addition to the cytosolic amino terminus are capable of inducing phenotypic effects in epithelial cells. Thus, rather than serving to modulate the activity of LMP2A, LMP2B may directly engage signaling pathways to influence epithelial cell behavior such as cell adhesion and motility.
VP40 Octamers Are Essential for Ebola Virus Replication
Authors: Hoenen Thomas , Volchkov Viktor , Kolesnikova Larissa , Mittler Eva , Timmins Joanna , Ottmann Michelle , Reynard Olivier , Becker Stephan , Weissenhorn Winfried 
Published: January 2005

ABSTRACT
Matrix protein VP40 of Ebola virus is essential for virus assembly and budding. Monomeric VP40 can oligomerize in vitro into RNA binding octamers, and the crystal structure of octameric VP40 has revealed that residues Phe125 and Arg134 are the most important residues for the coordination of a short single-stranded RNA. Here we show that full-length wild-type VP40 octamers bind RNA upon HEK 293 cell expression. While the Phe125-to-Ala mutation resulted in reduced RNA binding, the Arg134-to-Ala mutation completely abolished RNA binding and thus octamer formation. The absence of octamer formation, however, does not affect virus-like particle (VLP) formation, as the VLPs generated from the expression of wild-type VP40 and mutated VP40 in HEK 293 cells showed similar morphology and abundance and no significant difference in size. These results strongly indicate that octameric VP40 is dispensable for VLP formation. The cellular localization of mutant VP40 was different from that of wild-type VP40. While wild-type VP40 was present in small patches predominantly at the plasma membrane, the octamer-negative mutants were found in larger aggregates at the periphery of the cell and in the perinuclear region. We next introduced the Arg134-to-Ala and/or the Phe125-to-Ala mutation into the Ebola virus genome. Recombinant wild-type virus and virus expressing the VP40 Phe125-to-Ala mutation were both rescued. In contrast, no recombinant virus expressing the VP40 Arg134-to-Ala mutation could be recovered. These results suggest that RNA binding of VP40 and therefore octamer formation are essential for the Ebola virus life cycle.
Productive Interaction between Transmembrane Mutants of the Bovine Papillomavirus E5 Protein and the Platelet-Derived Growth Factor β Receptor
Authors: Lai Char-Chang , Edwards Anne P. B. , DiMaio Daniel 
Published: January 2005

ABSTRACT
The bovine papillomavirus E5 protein is a 44-amino-acid transmembrane protein that transforms cells by binding to the transmembrane region of the cellular platelet-derived growth factor (PDGF) β receptor, resulting in sustained receptor signaling. However, there are published reports that certain mutants with amino acid substitutions in the membrane-spanning segment of the E5 protein transform cells without activating the PDGF β receptor. We re-examined several of these transmembrane mutants, and here we present five lines of evidence that these mutants do in fact activate the PDGF β receptor, resulting in cellular signaling and transformation.
The Predominant Mechanism by Which Ribavirin Exerts Its Antiviral Activity In Vitro against Flaviviruses and Paramyxoviruses Is Mediated by Inhibition of IMP Dehydrogenase
Authors: Leyssen Pieter , Balzarini Jan , De Clercq Erik , Neyts Johan 
Published: January 2005

ABSTRACT

It is not yet clear to what extent depletion of intracellular GTP pools contributes to the antiviral activity of ribavirin. Therefore, the antiviral activities of (i) ribavirin, (ii) its 5-ethynyl analogue, 5-ethynyl-1-β-
d
-ribofuranosylimidazole-4-carboxamide (EICAR), and (iii) mycophenolic acid (MPA) (a compound that inhibits only cellular IMP dehydrogenase activity) were studied on the replication of flaviviruses and paramyxoviruses. In addition, the effects of these three compounds on intracellular GTP pools were assessed. A linear correlation was observed over a broad concentration range between the antiviral activities of ribavirin, EICAR, and MPA and the effects of these compounds on GTP pool depletion. When the 50% effective concentrations (EC
50
s) for the antiviral activities of ribavirin, EICAR, and MPA were plotted against the respective EC
50
values for GTP pool depletion, a linear correlation was calculated. These data provide compelling evidence that the predominant mechanism of action of ribavirin in vitro against flavi- and paramyxoviruses is based on inhibition of cellular IMP dehydrogenase activity.
Bovine Herpesvirus 1 VP22 Enhances the Efficacy of a DNA Vaccine in Cattle
Authors: Zheng Chunfu , Babiuk Lorne A. , van Drunen Littel-van den Hurk Sylvia 
Published: January 2005

ABSTRACTFor this study, the intercellular trafficking ability of bovine herpesvirus 1 (BHV-1) VP22 was applied to improve the efficacy of a DNA vaccine in calves. A plasmid encoding a truncated version of glycoprotein D (tgD) fused to VP22 was constructed. The plasmid encoding tgD-VP22 elicited significantly enhanced and more balanced immune responses than those induced by a plasmid encoding tgD. Furthermore, protection against a BHV-1 challenge was obtained in calves immunized with the plasmid encoding tgD-VP22, as shown by significant reductions in viral excretion. However, less significant protection was observed for animals vaccinated with the tgD-expressing plasmid, correlating with the lower level of immunity observed prechallenge. This is the first report of the use of VP22 as a transport molecule in the context of a DNA vaccine for a large animal species.
Vaccination with an Inactivated Virulent Feline Immunodeficiency Virus Engineered To Express High Levels of Env
Authors: Hosie Margaret J. , Klein Dieter , Binley James Μ. , Dunsford Thomas H. , Jarrett Oswald , Neil James C. , Knapp Elzbieta , Giannecchini Simone , Matteucci Donatella , Bendinelli Mauro , Hoxie James A. , Willett Brian J. 
Published: January 2005

ABSTRACTAn inactivated virus vaccine was prepared from a pathogenic isolate of feline immunodeficiency virus containing a mutation that eliminated an endocytic sorting signal in the envelope glycoprotein, increasing its expression on virions. Cats immunized with inactivated preparations of this modified virus exhibited strong titers of antibody to Env by enzyme-linked immunosorbent assay. Evidence of protection following challenge demonstrated the potential of this approach to lentiviral vaccination.
Aerosol Characterization and Direct Radiative Forcing Assessment over the Ocean. Part II: Application to Test Cases and Validation
Authors: Costa Maria João , Levizzani Vincenzo , Silva Ana Maria 
Published: January 2005

Abstract
A method based on the synergistic use of low earth orbit and geostationary earth orbit satellite data for aerosol-type characterization and aerosol optical thickness (AOT: τa) retrieval and monitoring over the ocean is presented in Part I of this paper. The method is now applied to a strong dust outbreak over the Atlantic Ocean in June 1997 and to two other relevant transport events of biomass burning and desert dust aerosol that occurred in 2000 over the Atlantic and Indian Oceans, respectively. The retrievals of the aerosol optical properties are checked against retrievals from sun and sky radiance measurements from the ground-based Aerosol Robotic Network (AERONET). The single-scattering albedo values obtained from AERONET are always within the error bars presented for Global Ozone Monitoring Experiment (GOME) retrievals, resulting in differences lower than 0.041. The retrieved AOT values are compared with the independent space–time-collocated measurements from the AERONET, as well as to the satellite aerosol official products of the Polarization and Directionality of the Earth Reflectances (POLDER) and the Moderate Resolution Imaging Spectroradiometer (MODIS). A first estimate of the AOT accuracy derived from comparisons with AERONET data leads to ±0.02 ± 0.22τa when all AOT values are retained or to ±0.02 ± 0.16τa for aerosol transport events (AOT &gt; 0.4). The upwelling flux at the top of the atmosphere (TOA) was computed with radiative transfer calculations and used to estimate the TOA direct shortwave aerosol radiative forcing; a comparison with space–time-collocated measurements from the Clouds and the Earth's Radiant Energy System (CERES) TOA flux product was also done. It was found that more than 90% of the values differ from CERES fluxes by less than ±15%.
Water Vapor Exchange between Soil and Atmosphere over a Gobi Surface near an Oasis in the Summer
Authors: Zhang Qiang , Huang Ronghui 
Published: January 2005

Abstract
Using data observed at Dunhuang, in the Gansu, in the arid region of northwest China in the summer, the characteristics of the soil water content, temperature, and atmospheric humidity were analyzed. It was found that the depth of the active soil temperature layer is about 5 cm, which is much thinner than that of typical soils. In addition, not only is the atmospheric humidity gradient in the surface layer often inverted, but so too is the soil water content gradient in the shallow layer. The diurnal variation of soil water content can be divided into four stages, including wet, water loss, dry, and water gain. It is shown that in soil water content profiles the depth of the active soil layer is about 10 cm, and soil water content inversion is the primary feature in the shallow layer during the “wet” stage. The presence of soil water content inversion indicates that soil in the shallow layer can absorb water from the air through condensation in the nighttime and emit water vapor to the air through evaporation in the daytime. The formation of a soil water content inversion is mainly related to the state of the soil surface temperature.
Precipitation Estimation from Remotely Sensed Imagery Using an Artificial Neural Network Cloud Classification System
Authors: Hong Yang , Hsu Kuo-Lin , Sorooshian Soroosh , Gao Xiaogang 
Published: January 2005

Abstract
A satellite-based rainfall estimation algorithm, Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN) Cloud Classification System (CCS), is described. This algorithm extracts local and regional cloud features from infrared (10.7 μm) geostationary satellite imagery in estimating finescale (0.04° × 0.04° every 30 min) rainfall distribution. This algorithm processes satellite cloud images into pixel rain rates by 1) separating cloud images into distinctive cloud patches; 2) extracting cloud features, including coldness, geometry, and texture; 3) clustering cloud patches into well-organized subgroups; and 4) calibrating cloud-top temperature and rainfall (Tb–R) relationships for the classified cloud groups using gauge-corrected radar hourly rainfall data. Several cloud-patch categories with unique cloud-patch features and Tb–R curves were identified and explained. Radar and gauge rainfall measurements were both used to evaluate the PERSIANN CCS rainfall estimates at a range of temporal (hourly and daily) and spatial (0.04°, 0.12°, and 0.25°) scales. Hourly evaluation shows that the correlation coefficient (CC) is 0.45 (0.59) at a 0.04° (0.25°) grid scale. The averaged CC of daily rainfall is 0.57 (0.63) for the winter (summer) season.
Background Error Correlation between Surface Skin and Air Temperatures: Estimation and Impact on the Assimilation of Infrared Window Radiances
Authors: Garand Louis , Buehner Mark , Wagneur Nicolas 
Published: January 2005

Abstract
This paper makes use of ensemble forecasts to infer the correlation between surface skin temperature Ts and air temperature Ta model errors. The impact of this correlation in data assimilation is then investigated. In the process of assimilating radiances that are sensitive to the surface skin temperature, the Ts–Ta error correlation becomes important because it allows statistically optimal corrections to the background temperature profile in the boundary layer. In converse, through this correlation, surface air temperature data can substantially influence the analysis of skin temperature. One difficulty is that the Ts–Ta correlation depends on the local static stability conditions that link the two variables. Therefore, a correlation estimate based on spatial or temporal averages is not appropriate. Ensembles of forecasts valid at the analysis time provide a novel means to infer the correlation dynamically at each model grid point. Geostationary Operational Environmental Satellite (GOES)-8 and -10 surface-sensitive imager radiances are assimilated with and without the inferred correlations in a 3D variational analysis system. The impact of the correlation on analyses is assessed using independent radiosonde data. The impact on 6-h forecasts is also evaluated using surface synoptic reports. The influence of the correlation extends from the surface to about 1.5 km. Temperature differences in the resulting analyses on the order of 0.3–0.6 K are typical in the boundary layer and may extend over broad regions. These difference patterns persist beyond 6 h into the forecasts.
Remote Cloud Ceiling Assessment Using Data-Mining Methods
Authors: Bankert Richard L. , Hadjimichael Michael , Kuciauskas Arunas P. , Thompson William T. , Richardson Kim 
Published: January 2005

Abstract
Data-mining methods are applied to numerical weather prediction (NWP) output and satellite data to develop automated algorithms for the diagnosis of cloud ceiling height in regions where no local observations are available at analysis time. A database of hourly records that include Coupled Ocean–Atmosphere Mesoscale Prediction System (COAMPS) output, satellite data, and ground truth observations [aviation routine weather reports (METAR)] has been created. Data were collected over a 2.5-yr period for specific locations in California. Data-mining techniques have been applied to the database to determine relationships in the collected physical parameters that best estimate cloud ceiling conditions, with an emphasis on low ceiling heights. Algorithm development resulted in a three-step approach: 1) determine if a cloud ceiling exists, 2) if a cloud ceiling is determined to exist, determine if the ceiling is high or low (below 1 000 m), and 3) if the cloud ceiling is determined to be low, compute ceiling height. A sample of the performance evaluation indicates an average absolute height error of 120.6 m with a 0.76 correlation and a root-mean-square error of 168.0 m for the low-cloud-ceiling testing set. These results are a significant improvement over the ceiling-height estimations generated by an operational translation algorithm applied to COAMPS output.
Dynamical Response of the Oceanic Eddy Field to the North Atlantic Oscillation: A Model–Data Comparison
Authors: Penduff Thierry , Barnier Bernard , Dewar W. K. , O'Brien James J. 
Published: January 2005

Abstract
Observational studies have shown that in many regions of the World Ocean the eddy kinetic energy (EKE) significantly varies on interannual time scales. Comparing altimeter-derived EKE maps for 1993 and 1996, Stammer and Wunsch have mentioned a significant meridional redistribution of EKE in the North Atlantic Ocean and suggested the possible influence of the North Atlantic Oscillation (NAO) cycle. This hypothesis is examined using 7 yr of Ocean Topography Experiment (TOPEX)/Poseidon altimeter data and three ⅙°-resolution Atlantic Ocean model simulations performed over the period 1979–2000 during the French “CLIPPER” experiment. The subpolar–subtropical meridional contrast of EKE in the real ocean appears to vary on interannual time scales, and the model reproduces it realistically. The NAO cycle forces the meridional contrast of energy input by the wind. The analysis in this paper suggests that after 1993 the large amplitude of the NAO cycle induces changes in the transport of the baroclinically unstable large-scale circulation (Gulf Stream/North Atlantic Current) and, thus, changes in the EKE distribution. Model results suggest that NAO-like fluctuations were not followed by EKE redistributions before 1994, probably because NAO oscillations were weaker. Strong NAO events after 1994 were followed by gyre-scale EKE fluctuations with a 4–12-month lag, suggesting that complex, nonlinear adjustment processes are involved in this oceanic adjustment.
Forcing of a Two-Layered Water Column over a Sloping Seafloor
Authors: Nilsen F. 
Published: January 2005

Abstract
The response of a time-dependent atmospheric function close to a slope region is studied. A forced two-layered model over a sloping topography is examined with focus on the particular solution and interaction between the constructed barotropic and baroclinic mode. The water column responds with long periodic waves along the sloping bottom, and the solution includes a time-dependent Ekman transport in the upper layer. Despite its relative simplicity, the model produces a resonant response in the barotropic mode to a northward-propagating plane-wave wind stress field. The particular solution shows that a state close to resonance in the barotropic mode is given by a 1/λy line for the barotropic coefficient when plotted as a function of the forcing wave period and wavelength λy. From the Norwegian Meteorological Institute (NMI) Hindcast database, the calculated time series of the wind stress curl reveals a high energy level in the forcing period interval between 48 and 185 h. The Vøring Plateau slope has a natural oscillation period around 100 h for topographically trapped waves, and the model shows that an along-slope wavelength of 76 km will produce a resonant response in the water column for this wave period. Hence, when the forcing function is constructed as a sum of (infinitely) many Fourier components, topographic waves will be triggered along the Vøring Plateau slope for a northward-moving atmospheric pressure system.