bluuebunny/crossref_metadata_2025 huggingface dataset:
IgA pemphigus – Occurrence of anti‐Desmocollin 1 and anti‐Desmoglein 1 antibody reactivity in an individual patient
Authors: Kopp Tamara , Sitaru Cassian , Pieczkowski Friederike , Schneeberger Achim , Födinger Dagmar , Zillikens Detlef , Stingl Georg , Karlhofer Franz M.
Published: November 2006

Background: IgA pemphigus is a rare pustular autoimmune disease with exclusive IgA anti‐keratinocyte cell surface antibody reactivity. Two subtypes have been discerned: in the subcorneal pustular dermatosis type, desmocollin 1 has been identified as a targeted autoantigen, while in few cases of the intraepidermal neutrophilic type, IgA anti‐desmoglein 1 or IgA anti‐desmoglein 3 reactivity has been demonstrated.

Patients and Methods: A 48‐year‐old white male presented with generalized large confluent pustules. Skin pathology was assessed by histology and direct immunofluorescence analysis. IgG/IgA autoantibodies against desmoglein 1/3 and desmocollin 1 were measured by ELISA and indirect immunofluorescence using desmocollin 1 cDNA‐transfected COS7 cells, respectively.

Results: Histopathology revealed subcorneal pustules and direct immunofluorescence microscopy exclusively showed in vivo bound IgA with an intercellular pattern in the epidermis. Desmocollin 1 was identified as a target of IgA autoantibodies by indirect immunofluorescence microscopy utilizing desmocollin 1 cDNA‐transfected COS7 cells. In addition, IgA anti‐desmoglein 1 reactivity was demonstrated by ELISA. Neither IgA anti‐desmoglein 3 nor IgG anti‐desmoglein 1/3 autoantibodies were present.

Conclusions: Both desmocollin 1 and desmoglein 1 were autoantigens in this patient with IgA pemphigus and a distinct clinical presentation. To our knowledge, this is the first IgA pemphigus case with dual autoantibody reactivity.
Mutational analysis of substrate recognition by human arginase type I − agmatinase activity of the N130D variant
Authors: Alarcón Ricardo , Orellana María S. , Neira Benita , Uribe Elena , García José R. , Carvajal Nelson
Published: November 2006

Upon mutation of Asn130 to aspartate, the catalytic activity of human arginase I was reduced to ∼ 17% of wild‐type activity, the Km value for arginine was increased ∼ 9‐fold, and the kcat/Km value was reduced ∼ 50‐fold. The kinetic properties were much less affected by replacement of Asn130 with glutamine. In contrast with the wild‐type and N130Q enzymes, the N130D variant was active not only on arginine but also on its decarboxylated derivative, agmatine. Moreover, it exhibited no preferential substrate specificity for arginine over agmatine (kcat/Km values of 2.48 × 103 m−1·s−1 and 2.14 × 103 m−1·s−1, respectively). After dialysis against EDTA and assay in the absence of added Mn2+, the N130D mutant enzyme was inactive, whereas about 50% full activity was expressed by the wild‐type and N130Q variants. Mutations were not accompanied by changes in the tryptophan fluorescence properties, thermal stability or chromatographic behavior of the enzyme. An active site conformational change is proposed as an explanation for the altered substrate specificity and low catalytic efficiency of the N130D variant.
Anti‐Tumour Necrosis Factor‐α Therapy in Heart Failure: Future Directions
Authors: Balakumar Pitchai , Singh Manjeet
Published: November 2006

Abstract: The elevated level of tumour necrosis factor‐α (TNF‐α) in patients with heart failure has triggered interest in investigating the role of TNF‐α in the pathogenesis of heart failure. Both clinical and experimental evidence has suggested that high levels of TNF‐α occur in heart failure and lead to progression of left ventricular dysfunction. In addition, it has been documented that inhibition of TNF‐α reverses its deleterious effects in heart failure. A number of clinical trials have been initiated to investigate the effect of anti‐TNF‐α therapy in patients with heart failure. The discouraging results of recent clinical trials of anti‐TNF‐α therapy in patients with heart failure have raised a number of questions about the role of TNF‐α in heart failure. The present review critically analyzes the reasons of failure of anti‐TNF‐α therapy in heart failure. Moreover the potential approaches for the development of new anti‐TNF‐α therapy has been discussed which may open new vista of the management of heart failure.
Modelling the effects of microclimate on bean seed desiccation rate and seed storage ability
Authors: Moreau‐Valancogne P. , Coste F. , Vandewalle P. , Wagner M.H. , Ladonne F. , Crozat Y.
Published: November 2006

Bean seed storage ability is of major interest for seed firms and depends, at least partially, on the effect of desiccation microclimate and desiccation rate on the mother plant; however, their effects are contradictory and not quantified. Therefore, our aims were (a) to predict seed desiccation rate from microclimatic variables at the pod level and (b) to measure the effects of seed desiccation rate and temperature on seed storage ability. For 4 years, beans (Phaseolus vulgaris) were sown at different dates in the field and once in a greenhouse. Pods having seeds at the beginning of desiccation stage were selected according to their colour and then dried in the field or under controlled conditions. In the field, pods were dried under both natural conditions and conditions modified either by defoliation or by water spraying. Under controlled conditions, pods were dried under a wide range of temperature and relative humidity combinations. Seed water content, temperature and relative humidity were measured throughout the desiccation phase. Storage ability was measured by a standard germination test after either 11 or 15 days of controlled deterioration. Seed desiccation rate was highly correlated to air vapour pressure deficit, which measures the combined effects of temperature and relative humidity on drying. With a logit transformation, deterioration test results showed a linear decrease in storage ability as seed desiccation rate increased for either controlled or field‐dried lots. However, for controlled lots desiccated at temperatures lower than 24°C, the lower the temperature, the lower the storage ability at a given desiccation rate. Moreover, the relationship between the results of the two deterioration periods differed between controlled and field‐dried lots. Finally, the high correlation between seed storage ability, desiccation rate and vapour pressure deficit in the field has given new insights for building a crop decision‐oriented model for optimising harvesting.
Discrimination between agricultural management and the hedge effect in pear orchards (south‐eastern France)
Authors: Debras J.‐F. , Torre F. , Rieux R. , Kreiter S. , Garcin M.S. , Van Helden M. , Buisson E. , Dutoit T.
Published: November 2006

The arthropod populations in five pear orchards were sampled by beating branches twice a month during the year 2003 in the Provence region of south‐eastern France. Multivariate analyses linking the matrix of species with a certain number of environmental variables (distance from the hedge, type of agricultural practices in the orchard, year effect, etc.) were performed to identify the most explanatory variables in terms of composition and structure (richness and equitability) of different arthropod populations. Univariate analyses were performed on descriptive population variables (numbers, diversity and richness) to highlight intrasite or intersite differences. These analyses revealed significant differences in the composition of orchard populations. The variance revealed by all environmental variables explained 28.7% of population composition. The variance revealed by hedge variables only explained 2.2% of population composition, while that revealed by variables concerning management practices explained 12.4%.
Overview of the Development of Solid Oxide Fuel Cells at Forschungszentrum Juelich
Authors: Steinberger‐Wilckens Robert , Blum Ludger , Buchkremer Hans‐Peter , Gross Sonja , De Haart L.(Bert) , Hilpert Klaus , Nabielek Heinz , Quadakkers Willem (Jo) , Reisgen Ulrich , Steinbrech Rolf W , Tietz Frank
Published: November 2006

The SOFC group at Forschungszentrum Juelich has assembled and tested more than 220 SOFC stacks during the last 10 years, rated between 100 W and 15 kW. The topics of high‐performance materials, corrosion, materials compatibility, and cost‐effectiveness, including manufacturing processes, etc., are being continuously addressed. Large stacks of 5 kW and above have been operated since 2002 and have also been successfully delivered to other institutions. In parallel, lightweight stacks have been developed in the “cassette” design line for SOFC‐APU. Several 1–20 kW SOFC laboratory systems are in preparation.
Influences of the Glass Phase on Densification, Microstructure, and Properties of Low‐Temperature Co‐Fired Ceramics
Authors: Eberstein Markus , Rabe Torsten , Schiller Wolfgang Arno
Published: November 2006

Multilayer ceramic devices based on low‐temperature co‐fired ceramics (LTCC) materials provide a very promising technology. Most LTCC tapes available today contain considerable fractions of glass powders to lower the sintering temperature. However, the glassy phases offer more possibilities to set a proper sintering behavior, on the one hand, and to tailor the desired properties of the final LTCC substrate, on the other. The exploitation of demixing and subsequent crystallizing glass compositions was shown on an example of a low‐permittivity (4.4)—low‐loss (1.5 × 10−3) LTCC with a high quartz content. In another LTCC material, undesired demixing could be restricted and the crystal phase anorthite could be triggered by partial dissolution of alumina in the liquid phase during sintering. To estimate the effect of silver diffusion in the latter material, the surroundings of a pure silver via were studied. A silver‐contaminated range of 50 μm was detected. Using model glasses containing silver oxide, a strong influence of dissolved silver on viscosity and crystallization behavior of the liquid phase was demonstrated. The dielectric properties of the sintered substrates were not degraded.
Novel O‐superfamily Conotoxins Identified by cDNA Cloning From Three Vermivorous Conus Species
Authors: Zhangsun Dongting , Luo Sulan , Wu Yong , Zhu Xiaopeng , Hu Yuanyan , Xie Lei
Published: November 2006

The O‐superfamily of conotoxins includes several subfamilies with different pharmacological targets, all of which are voltage‐gated ion channels and distributed widely in varied Conus species. The venom components from any Conus species are quite distinct from those of other species. Seven novel O‐superfamily peptides were identified by cDNA cloning from the three vermivorous Conus species of C. betulinus, C. lividus and C. caracteristicus native to Hainan. They share three common signal sequences, and a conserved arrangement of cysteine residues (C–C–CC–C–C). Phylogenetic analysis of newly found conotoxins in this study and known homologue O‐superfamily sequences from the other Conus species was performed systematically. Divergence and percentage identity of the amino acid sequences of the signal regions suggest that the novel conotoxins described in this investigation belong to the three broad clades: MSGL, ME‐QK and MKLT, each of which has its own characteristic signature signal sequence and cysteine codon conservation. Relative to this work, it is noted that O‐superfamily conotoxins are not well represented from vermivorous species. The elucidated cDNAs of these newly found vermivorous toxins would facilitate a better understanding for basic research and drug discovery.
Interactions between Conserved Residues in Transmembrane Helices 2 and 7 during Angiotensin AT1 Receptor Activation
Authors: Nikiforovich Gregory V. , Zhang Meng , Yang Qing , Jagadeesh Gowraganahalli , Chen Hao‐Chia , Hunyady László , Marshall Garland R. , Catt Kevin J.
Published: November 2006

Site‐directed mutagenesis studies and independent molecular modeling studies were combined to investigate the network of inter‐residue interactions within the transmembrane region of the angiotensin AT1a receptor. Site‐directed mutagenesis was focused on residues Tyr292, Asn294, Asn295, and Asn298 in transmembrane helix 7, and the conserved Asp74 in helix 2 and other polar residues. Functional interactions between pairs of residues were evaluated by determining the effects of single and double‐reciprocal mutations on agonist‐induced AT1a receptor activation. Replacement of Tyr292 by aspartate in helix 7 abolished radioligand binding to both Y292D and D74Y/Y292D mutant receptors. Reciprocal mutations of Asp74/Asn294, Ser115/Asn294, Ser252/Asn294, and Asn298/Sen115 caused additive impairment of function, suggesting that these pairs of residues make independent contributions to AT1a receptor activation. In contrast, mutations of the Asp74/Tyr298 pair revealed that the D74N/N298D reciprocal mutation substantially increased the impaired inositol phosphate responses of the D74N and N298D receptors. Extensive molecular modeling yielded 3D models of the TM region of the AT1 receptor and the mutants as well as of their complexes with angiotensin II, which were used to rationalize the possible reasons of impairing of function of some mutants. These data indicate that Asp74 and Asn298 are not optimally positioned for direct strong interaction in the resting conformation of the AT1a receptor. Balance of interactions between residues in helix 2 (as D74) and helix 7 (as N294, N295 and N298) in the AT1 receptors, however, has a crucial role both in determining their functional activity and levels of their expression.
Identification of Human dim1 as a Peptidase with Autocleavage Activity
Authors: Jin Tengchuan , Guo Feng , Wang Yingtong , Zhang Yu‐Zhu
Published: November 2006

Dim1 is a highly conserved splicing factor. It is encoded by an essential gene in fission yeast and the Caenorhabditis elegans. It may also be involved in tissue‐specific or pathway‐specific alternative splicing. Here, we report that besides its function in pre‐mRNA splicing, human dim1 is a peptidase and has autocleavage activity. Its autocleavage results in a thioredoxin‐like core that was shown previously to act as a dominant negative in fission yeast. The truncated form retains its peptidase activity. Future studies will be needed to identify residues important for dim1–peptidase activity and to characterize its substrate specificity. The biologic importance of dim1’s peptidase function and its natural substrate(s) also need to be determined. However, if one or more of its substrates is involved in the pathogenesis of a human disease, dim1 may become a new target for drug development.
Experimental Philosophy
Authors: Knobe Joshua
Published: November 2006

Claims about people's intuitions have long played an important role in philosophical debates. The new field of experimental philosophy seeks to subject such claims to rigorous tests using the traditional methods of cognitive science – systematic experimentation and statistical analysis. Work in experimental philosophy thus far has investigated people's intuitions in philosophy of language, philosophy of mind, epistemology, and ethics. Although it is now generally agreed that experimental philosophers have made surprising discoveries about people's intuitions in each of these areas, considerable disagreement remains about the philosophical significance of the key findings. Some have argued that work in experimental philosophy should be assessed by asking whether it can contribute to the kind of inquiry that is normally pursued within analytic philosophy, while others suggest that work in experimental philosophy is best understood as a contribution to a more traditional sort of philosophical inquiry that long predates the birth of analytic philosophy.
Hermaphroditism in Cultured Chinese Black Sleeper (Bostrichthys sinensis L.)
Authors: Hong Wan Shu , Chen Shi Xi , Zheng Wei Yun , Xiao Ying , Zhang Qi Yong
Published: November 2006

Anatomical studies showed that all collected feral fish of Chinese black sleepers (Bostrichthys sinensis L.) were gonochoristic. In contrast, an average of 12.4% of cultured fish appeared to be hermaphroditic. The shape of the genital papilla of hermaphroditic specimens resembled that of gonochoristic males. The gonadosomatic index (IG) of hermaphroditic fish varied from 0.24 to 4.48%, while that of gonochoristic conspecifics varied from 6.1 to 12.2% for females and 0.11 to 0.14% for males. Histological studies revealed that the sex organs of hermaphrodites consisted of ovarian, testicular, and seminal vesicle tissues, located in the central, peripheral, and caudal region of the gonads, respectively. During the spawning season, ovarian tissue contained poorly developed oocytes, that is, hydrated oocytes were absent and only a few degenerated vitellogenic oocytes were present. Testicular tissue, however, contained fully developed spermatozoa. The fertilization rate of these spermatozoa was significantly lower than those of gonochoristic conspecifics. It is concluded that part of the cultured stock of Chinese black sleeper became hermaphroditic during culture and that the hermaphrodites are able to function as males. The lowered fertilization rate, however, indicates that hermaphroditism in cultured fish of this species is disadvantageous to reproduction.
Dietary Lysine Requirement as Basis to Estimate the Essential Dietary Amino Acid Profile for Jundiá, Rhamdia quelen
Authors: Montes‐Girao Pamela J. , Fracalossi Débora M.
Published: November 2006

The present study was designed to determine the optimal dietary lysine requirement for jundiá, Rhamdia quelen, fingerlings. Groups of 17 fish (1.4 ± 0.1 g) were stocked in 120‐L tanks and were fed semipurified diets (33% crude protein [CP] and 3500 kcal metabolizable energy) containing increasing concentrations of lysine (3.0, 4.0, 4.5, 5.0, 5.5, 6.0, and 6.5% CP). After 119 d, fish weight gain (WG), specific growth rate (SGR), feed intake and feed conversion (FC), apparent net protein utilization (ANPU), body composition (CP, fat, and ash), and vertebral collagen were determined. WG and SGR increased as dietary lysine concentration in protein increased up to 4.5%, reducing at 6.0 and 6.5% lysine. Fish that were fed the lowest lysine concentration presented the worst feed conversion (FC), which improved for fish fed with 4.5% or more lysine. Feed consumption followed the same trend as FC. The highest ANPU was observed in fish fed with 4.5% lysine. Fish fed diets containing 4.5, 5.0, and 5.5% lysine accumulated more body protein (P < 0.05). Collagen vertebral concentration was significantly higher in fish fed with the 4.5% lysine diet. Dietary requirement for lysine was 4.5 or 5.1% depending on the statistical model used for estimation: broken line or polynomial regression, respectively. The requirements for the other essential amino acids were estimated on the basis of the ideal protein concept and were similar to the requirements for other fish species, except for isoleucine, leucine, treonine, and valine, which were higher for jundiá.
Economic Analysis of Nile Tilapia (Oreochromis niloticus) Production in Tanzania
Authors: Kaliba Aloyce R , Osewe Kajitanus O , Senkondo Ephraim M , Mnembuka Berno V , Quagrainie Kwamena K
Published: November 2006

In Tanzania, Nile tilapia culture is a promising aquaculture enterprise. Information on production costs could assist fish farmers in economic and financial planning. Economic profitability of small‐scale Nile tilapia production in Tanzania is analyzed using a model that simulates individual fish growth and takes into account fish population dynamics in the pond. The results suggest that the current practiced mixed‐sex tilapia culture without predation is not economically sustainable. Extension efforts should be geared toward developing a Nile tilapia production system that is based on a hand‐sexed all‐male tilapia. Meanwhile catfish can be introduced in ponds to control overcrowding in mixed‐sex tilapia culture without predation. Studies to determine optimal pond sizes, availability of feed, and a quality fingerling supply chain are also fundamental for developing a sustainable Nile tilapia production system in Tanzania. Under improved Nile tilapia production systems, returns are high enough to justify investment through borrowed capital from formal institutions.
Buddhism and Caste in India and Sri Lanka
Authors: Samuels Jeffrey
Published: November 2006

This article examines the place of caste in Buddhism in India and Sri Lanka. In addition to suggesting a way of reconciling divergent attitudes toward caste in the Pali canon and several Sanskrit texts, this article explores the role that caste has played in the creation of new monastic lineages in eighteenth‐, nineteenth‐, and twentieth‐century Sri Lanka, as well as its role in monastic patronage and temple building in contemporary Sri Lanka.
Islam and Democracy: Is Modernization a Barrier?
Authors: Voll John O.
Published: November 2006

The relationship between Islam and democracy is a hotly debated topic. Usually the disagreements are expressed in a standard form. In this form, the debaters’ definitions of “Islam” and “democracy” determine the conclusions arrived at. It is possible, depending upon the definitions used, to “prove” both positions: Islam and democracy are compatible and that they are not. To escape from the predefined conclusions, it is necessary to recognize that “Islam” and “democracy” are concepts with many definitions. In the twenty‐first century, important interpretations of Islam open the way for political visions in which Islam and democracy are mutually supportive.
Respiratory Syncytial Virus F Envelope Protein Associates with Lipid Rafts without a Requirement for Other Virus Proteins
Authors: Fleming Elisa H. , Kolokoltsov Andrey A. , Davey Robert A. , Nichols Joan E. , Roberts Norbert J.
Published: November 2006

Like many enveloped viruses, human respiratory syncytial virus (RSV) assembles at and buds from lipid rafts. Translocation of the envelope proteins to these membrane subdomains is essential for production of infectious virus, but the targeting mechanism is poorly understood and it is not known if other virus proteins are required. Here we demonstrate that F protein of RSV intrinsically targets to lipid rafts without a requirement for any other virus protein, including the SH and G envelope proteins. Recombinant virus deficient in SH and G but retaining F protein expression was used to demonstrate that F protein still localized in rafts in both A549 and HEp-2 cells. Expression of a recombinant F gene by use of plasmid vectors demonstrated that F contains its own targeting domain and localized to rafts in the absence of other virus proteins. The domain responsible for translocation was then mapped. Unlike most other virus envelope proteins, F is unusual since the target signal is not contained within the cytoplasmic domain nor did it involve fatty acid modified residues. Furthermore, exchange of the transmembrane domain with that of the vesicular stomatitis virus G protein, a nonraft protein, did not alter F protein raft localization. Taken together, these data suggest that domains present in the extracellular portion of the protein are responsible for lipid raft targeting of the RSV F protein.
Evidence of Influenza A Virus RNA in Siberian Lake Ice
Authors: Zhang Gang , Shoham Dany , Gilichinsky David , Davydov Sergei , Castello John D. , Rogers Scott O.
Published: November 2006

Influenza A virus infects a large proportion of the human population annually, sometimes leading to the deaths of millions. The biotic cycles of infection are well characterized in the literature, including in studies of populations of humans, poultry, swine, and migratory waterfowl. However, there are few studies of abiotic reservoirs for this virus. Here, we report the preservation of influenza A virus genes in ice and water from high-latitude lakes that are visited by large numbers of migratory birds. The lakes are along the migratory flight paths of birds flying into Asia, North America, Europe, and Africa. The data suggest that influenza A virus, deposited as the birds begin their autumn migration, can be preserved in lake ice. As birds return in the spring, the ice melts, releasing the viruses. Therefore, temporal gene flow is facilitated between the viruses shed during the previous year and the viruses newly acquired by birds during winter months spent in the south. Above the Arctic Circle, the cycles of entrapment in the ice and release by melting can be variable in length, because some ice persists for several years, decades, or longer. This type of temporal gene flow might be a feature common to viruses that can survive entrapment in environmental ice and snow.
Strain Fidelity of Chronic Wasting Disease upon Murine Adaptation
Authors: Sigurdson Christina J. , Manco Giuseppe , Schwarz Petra , Liberski Pawel , Hoover Edward A. , Hornemann Simone , Polymenidou Magdalini , Miller Michael W. , Glatzel Markus , Aguzzi Adriano
Published: November 2006

Chronic wasting disease (CWD), a prion disease of deer and elk, is highly prevalent in some regions of North America. The establishment of mouse-adapted CWD prions has proven difficult due to the strong species barrier between mice and deer. Here we report the efficient transmission of CWD to transgenic mice overexpressing murine PrP. All mice developed disease 500 ± 62 days after intracerebral CWD challenge. The incubation period decreased to 228 ± 103 days on secondary passage and to 162 ± 6 days on tertiary passage. Mice developed very large, radially structured cerebral amyloid plaques similar to those of CWD-infected deer and elk. PrP
Sc
was detected in spleen, indicating that murine CWD was lymphotropic. PrP
Sc
glycoform profiles maintained a predominantly diglycosylated PrP pattern, as seen with CWD in deer and elk, across all passages. Therefore, all pathological, biochemical, and histological strain characteristics of CWD appear to persist upon repetitive serial passage through mice. These findings indicate that the salient strain-specific properties of CWD are encoded by agent-intrinsic components rather than by host factors.
Analyses of the Interaction between the Origin Binding Domain from Simian Virus 40 T Antigen and Single-Stranded DNA Provide Insights into DNAUnwinding and Initiation of DNA Replication
Authors: Reese Danielle K. , Meinke Gretchen , Kumar Anuradha , Moine Stephanie , Chen Kathleen , Sudmeier James L. , Bachovchin William , Bohm Andrew , Bullock Peter A.
Published: November 2006

DNA
helicases are essential for DNA metabolism; however, at the molecular
level little is known about how they assemble or function. Therefore,
as a model for a eukaryotic helicase, we are analyzing T antigen (T-ag)
the helicase encoded by simian virus 40. In this study, nuclear
magnetic resonance (NMR) methods were used to investigate the transit
of single-stranded DNA (ssDNA) through the T-ag origin-binding domain
(T-ag OBD). When the residues that interact with ssDNA are viewed in
terms of the structure of a hexamer of the T-ag OBD, comprised of
residues 131 to 260, they indicate that ssDNA passes over one face of
the T-ag OBD and then transits through a gap in the open ring
structure. The NMR-based conclusions are supported by an analysis of
previously described mutations that disrupt critical steps during the
initiation of DNA replication. These and related observations are
discussed in terms of the threading of DNA through T-ag hexamers and
the initiation of viral DNA
replication.
Characterization of an Immunodominant Antigenic Site on GB Virus C Glycoprotein E2 That Is Involved in Cell Binding
Authors: McLinden James H. , Kaufman Thomas M. , Xiang Jinhua , Chang Qing , Klinzman Donna , Engel Alfred M. , Hess Georg , Schmidt Urban , Houghton Michael , Stapleton Jack T.
Published: November 2006

GB virus type C (GBV-C) is a human flavivirus that may cause persistent infection, although most infected individuals clear viremia and develop antibodies to the envelope glycoprotein E2. To study GBV-C E2 antigenicity and cell binding, murine anti-E2 monoclonal antibodies (MAbs) were evaluated to topologically map immunogenic sites on GBV-C E2 and for the ability to detect or block recombinant E2 binding to various cell lines. Five competition groups of MAbs were identified. Groups I and II did not compete with each other. Group III competed with both groups I and II. Group IV did not compete with group I, II, or III. One MAb competed with all of the other MAbs, suggesting that the epitopes bound by these MAbs are intimately related. Individually, none of the MAbs competed extensively with polyclonal human convalescent antibody (PcAb); however, combinations of all five MAb groups completely blocked PcAb binding to E2, suggesting that the epitopes bound by these MAbs form a single, immunodominant antigenic site. Only group I and III MAbs detected purified recombinant E2 bound to cells in binding assays. In contrast, group II MAbs neutralized the binding of E2 to cells. Both PcAb and MAbs were conformation dependent, with the exception of one group II MAb (M6). M6 bound to a five-amino-acid sequence on E2 if the peptide included four C-terminal or eight N-terminal residues, suggesting that the GBV-C E2 protein contains a single immunodominant antigenic site which includes a complex epitope that is involved in specific cellular binding.
Reovirus μ1 Structural Rearrangements That Mediate Membrane Penetration
Authors: Zhang Lan , Chandran Kartik , Nibert Max L. , Harrison Stephen C.
Published: November 2006

Membrane penetration by nonenveloped reoviruses is mediated by the outer-capsid protein, μ1 (76 kDa). Previous evidence has suggested that an autolytic cleavage in μ1 allows the release of its N-terminally myristoylated peptide, μ1N (4 kDa), which probably then interacts with the target-cell membrane. A substantial rearrangement of the remaining portion of μ1, μ1C (72 kDa), must also have occurred for μ1N to be released, and some regions in μ1C may make additional contacts with the membrane. We describe here a particle-free system to study conformational rearrangements of μ1. We show that removal of the protector protein σ3 is not sufficient to trigger rearrangement of free μ1 trimer and that free μ1 trimer undergoes conformational changes similar to those of particle-associated μ1 when induced by similar conditions. The μ1 rearrangements require separation of the μ1 trimer head domains but not the μ1N/C autocleavage. We have also obtained a relatively homogeneous form of the structurally rearranged μ1 (μ1*) in solution. It is an elongated monomer and retains substantial α-helix content. We have identified a protease-resistant ∼23-kDa fragment of μ1*, which contains the largely α-helical regions designated domains I and II in the conformation of μ1 prior to rearrangement. We propose that the μ1 conformational changes preceding membrane penetration or disruption during cell entry involve (i) separation of the β-barrel head domains in the μ1 trimer, (ii) autolytic cleavage at the μ1N/C junction, associated with partial unfolding of μ1C and release of μ1N, and (iii) refolding of the N-terminal helical domains of μ1C, with which μ1N was previously complexed, accompanied by dissociation of the μ1 trimer.
Mutational Analysis of the Lassa Virus Promoter
Authors: Hass Meike , Westerkofsky Martina , Müller Stefanie , Becker-Ziaja Beate , Busch Carola , Günther Stephan
Published: November 2006

The
promoter sequences directing viral gene expression and genome
replication of arenaviruses reside within the 3′ and 5′
termini of each RNA segment. The terminal 19 nucleotides at both ends
are highly conserved among all arenavirus species and are almost
completely complementary to each other. This study aimed at
characterizing the Lassa virus promoter in detail. The relevance of
each position in the promoter was studied by site-directed mutagenesis
using the Lassa virus minireplicon system. The data indicate that the
Lassa virus promoter functions as a duplex, regulates transcription and
replication in a coordinated manner, and is composed of two functional
elements, a sequence-specific region from residue 1 to 12 and a
variable complementary region from residue 13 to 19. The first region
appears to interact with the replication complex mainly via
base-specific interactions, while in the second region solely base
pairing between 3′ and 5′ promoter ends is important
for promoter
function.
NFAT4 Is Required for JC Virus Infection of Glial Cells
Authors: Manley Kate , O'Hara Bethany A. , Gee Gretchen V. , Simkevich Carl P. , Sedivy John M. , Atwood Walter J.
Published: November 2006

The human polyomavirus JC virus (JCV) infects 70% of the population worldwide. In immunosuppressed patients, JCV infection can lead to progressive multifocal leukoencephalopathy (PML), a fatal demyelinating disease of the central nervous system (CNS). The majority of PML cases occur in the setting of human immunodeficiency virus (HIV) infection, and it has been suggested that the link between HIV and the development of PML is in part related to the production of numerous cytokines in the CNS during HIV infection. To examine the link between the expression of inflammatory cytokines and JCV infection, we tested an anti-inflammatory compound, cyclosporine A (CsA), for its ability to block JCV infection of glial cells. We found that CsA inhibited JCV infection by preventing the activation of the transcription factor nuclear factor of activated T cells 4 (NFAT4). Luciferase reporter assays and chromatin immunoprecipitation assays revealed that NFAT4 directly bound the JCV promoter during infection and was important for the activation of both early and late transcription. In addition, the expression of the JCV early viral gene products increased NFAT activity to further aid viral transcription. The necessity of NFAT for JCV infection suggests that calcium signaling and the activation of NFAT in glial cells are required for JCV infection of the CNS.
Access to Nectin Favors Herpes Simplex Virus Infection at the Apical Surface of Polarized Human Epithelial Cells
Authors: Galen Benjamin , Cheshenko Natalia , Tuyama Ana , Ramratnam Bharat , Herold Betsy C.
Published: November 2006

Viral entry may preferentially occur at the apical or the basolateral surfaces of polarized cells, and differences may impact pathogenesis, preventative strategies, and successful implementation of viral vectors for gene therapy. The objective of these studies was to examine the polarity of herpes simplex virus (HSV) entry using several different human epithelial cell lines. Human uterine (ECC-1), colonic (CaCo-2), and retinal pigment (ARPE-19) epithelial cells were grown on collagen-coated inserts, and the polarity was monitored by measuring the transepithelial cell resistance. Controls were CaSki cells, a human cervical cell line that does not polarize in vitro. The polarized cells, but not CaSki cells, were 16- to 50-fold more susceptible to HSV infection at the apical surface than at the basolateral surface. Disruption of the tight junctions by treatment with EGTA overcame the restriction on basolateral infection but had no impact on apical infection. No differences in binding at the two surfaces were observed. Confocal microscopy demonstrated that nectin-1, the major coreceptor for HSV entry, sorted preferentially to the apical surface, overlapping with adherens and tight junction proteins. Transfection with small interfering RNA specific for nectin-1 resulted in a significant reduction in susceptibility to HSV at the apical surface but had little impact on basolateral infection. Infection from the apical but not the basolateral surface triggered focal adhesion kinase phosphorylation and led to nuclear transport of viral capsids and viral gene expression. These studies indicate that access to nectin-1 contributes to preferential apical infection of these human epithelial cells by HSV.
Preclinical Model To Test Human Papillomavirus Virus (HPV) Capsid Vaccines In Vivo Using Infectious HPV/Cottontail Rabbit Papillomavirus Chimeric Papillomavirus Particles
Authors: Mejia Andres F. , Culp Timothy D. , Cladel Nancy M. , Balogh Karla K. , Budgeon Lynn R. , Buck Christopher B. , Christensen Neil D.
Published: November 2006

A human papillomavirus (HPV) vaccine consisting of virus-like particles (VLPs) was recently approved for human use. It is generally assumed that VLP vaccines protect by inducing type-specific neutralizing antibodies. Preclinical animal models cannot be used to test for protection against HPV infections due to species restriction. We developed a model using chimeric HPV capsid/cottontail rabbit papillomavirus (CRPV) genome particles to permit the direct testing of HPV VLP vaccines in rabbits. Animals vaccinated with CRPV, HPV type 16 (HPV-16), or HPV-11 VLPs were challenged with both homologous (CRPV capsid) and chimeric (HPV-16 capsid) particles. Strong type-specific protection was observed, demonstrating the potential application of this approach.
Human Immunodeficiency Virus Type 1 Resistance to the Small Molecule Maturation Inhibitor 3-
O
-(3′,3′-Dimethylsuccinyl)-Betulinic Acid Is Conferred by a Variety of Single Amino Acid Substitutions at the CA-SP1 Cleavage Site in Gag
Authors: Zhou Jing , Chen Chin Ho , Aiken Christopher
Published: November 2006

The compound 3-
O
-(3′,3′-dimethylsuccinyl)-betulinic acid (DSB) potently and specifically inhibits human immunodeficiency virus type 1 (HIV-1) replication by delaying the cleavage of the CA-SP1 junction in Gag, leading to impaired maturation of the viral core. In this study, we investigated HIV-1 resistance to DSB by analyzing HIV-1 mutants encoding a variety of individual amino acid substitutions in the CA-SP1 cleavage site. Three of the substitutions were lethal to HIV-1 replication owing to a deleterious effect on particle assembly. The remaining mutants exhibited a range of replication efficiencies; however, each mutant was capable of replicating in the presence of concentrations of DSB that effectively inhibited wild-type HIV-1. Mutations conferring resistance to DSB also led to impaired binding of the compound to immature HIV-1 virions and loss of DSB-mediated inhibition of cleavage of Gag. Surprisingly, two of the DSB-resistant mutants retained an intermediate ability to bind the compound, suggesting that binding of DSB to immature HIV-1 particles may not be sufficient for antiviral activity. Overall, our results indicate that Gag amino acids L363 and A364 are critical for inhibition of HIV-1 replication by DSB and suggest that these residues form key contacts with the drug in the context of the assembling HIV-1 particle. These results have implications for the design of and screening for novel inhibitors of HIV-1 maturation.
Inhibition of Influenza Virus Infection by a Novel Antiviral Peptide That Targets Viral Attachment to Cells
Authors: Jones Jeremy C. , Turpin Elizabeth A. , Bultmann Hermann , Brandt Curtis R. , Schultz-Cherry Stacey
Published: November 2006

Influenza A viruses continue to cause widespread morbidity and mortality. There is an added concern that the highly pathogenic H5N1 influenza A viruses, currently found throughout many parts of the world, represent a serious public health threat and may result in a pandemic. Intervention strategies to halt an influenza epidemic or pandemic are a high priority, with an emphasis on vaccines and antiviral drugs. In these studies, we demonstrate that a 20-amino-acid peptide (EB, for entry blocker) derived from the signal sequence of fibroblast growth factor 4 exhibits broad-spectrum antiviral activity against influenza viruses including the H5N1 subtype in vitro. The EB peptide was protective in vivo, even when administered postinfection. Mechanistically, the EB peptide inhibits the attachment to the cellular receptor, preventing infection. Further studies demonstrated that the EB peptide specifically binds to the viral hemagglutinin protein. This novel peptide has potential value as a reagent to study virus attachment and as a future therapeutic.
Antibody Recognition and Neutralization Determinants on Domains I and II of West Nile Virus Envelope Protein
Authors: Oliphant Theodore , Nybakken Grant E. , Engle Michael , Xu Qing , Nelson Christopher A. , Sukupolvi-Petty Soila , Marri Anantha , Lachmi Bat-El , Olshevsky Udy , Fremont Daved H. , Pierson Theodore C. , Diamond Michael S.
Published: November 2006

Previous studies have demonstrated that monoclonal antibodies (MAbs) against an epitope on the lateral surface of domain III (DIII) of the West Nile virus (WNV) envelope (E) strongly protect against infection in animals. Herein, we observed significantly less efficient neutralization by 89 MAbs that recognized domain I (DI) or II (DII) of WNV E protein. Moreover, in cells expressing Fc γ receptors, many of the DI- and DII-specific MAbs enhanced infection over a broad range of concentrations. Using yeast surface display of E protein variants, we identified 25 E protein residues to be critical for recognition by DI- or DII-specific neutralizing MAbs. These residues cluster into six novel and one previously characterized epitope located on the lateral ridge of DI, the linker region between DI and DIII, the hinge interface between DI and DII, and the lateral ridge, central interface, dimer interface, and fusion loop of DII. Approximately 45% of DI-DII-specific MAbs showed reduced binding with mutations in the highly conserved fusion loop in DII: 85% of these (34 of 40) cross-reacted with the distantly related dengue virus (DENV). In contrast, MAbs that bound the other neutralizing epitopes in DI and DII showed no apparent cross-reactivity with DENV E protein. Surprisingly, several of the neutralizing epitopes were located in solvent-inaccessible positions in the context of the available pseudoatomic model of WNV. Nonetheless, DI and DII MAbs protect against WNV infection in mice, albeit with lower efficiency than DIII-specific neutralizing MAbs.
Immunogenicity of Heterologous Recombinant Adenovirus Prime-Boost Vaccine Regimens Is Enhanced by Circumventing Vector Cross-Reactivity
Authors: Thorner Anna R. , Lemckert Angelique A. C. , Goudsmit Jaap , Lynch Diana M. , Ewald Bonnie A. , Denholtz Matthew , Havenga Menzo J. E. , Barouch Dan H.
Published: November 2006

The high prevalence of preexisting immunity to adenovirus serotype 5 (Ad5) in human populations has led to the development of recombinant adenovirus (rAd) vectors derived from rare Ad serotypes as vaccine candidates for human immunodeficiency virus type 1 and other pathogens. Vaccine vectors have been constructed from Ad subgroup B, including rAd11 and rAd35, as well as from Ad subgroup D, including rAd49. However, the optimal combination of vectors for heterologous rAd prime-boost vaccine regimens and the extent of cross-reactive vector-specific neutralizing antibodies (NAbs) remain poorly defined. We have shown previously that the closely related vectors rAd11 and rAd35 elicited low levels of cross-reactive NAbs. Here we show that these cross-reactive NAbs correlated with substantial sequence homology in the hexon hypervariable regions (HVRs) and suppressed the immunogenicity of heterologous rAd prime-boost regimens. In contrast, vectors with lower hexon HVR homology, such as rAd35 and rAd49, did not elicit detectable cross-reactive vector-specific NAbs. Consistent with these findings, rAd35-rAd49 vaccine regimens proved more immunogenic than both rAd35-rAd5 and rAd35-rAd11 regimens in mice with anti-Ad5 immunity. These data suggest that optimal heterologous rAd prime-boost regimens should include two vectors that are both rare in human populations to circumvent preexisting antivector immunity as well as sufficiently immunologically distinct to avoid cross-reactive antivector immunity.
NO2and children’s respiratory symptoms in the PATY study
Authors: Pattenden S , Hoek G , Braun-Fahrländer C , Forastiere F , Kosheleva A , Neuberger M , Fletcher T
Published: November 2006

Objectives:NO2is a major urban air pollutant. Previously reported associations between ambient NO2and children’s respiratory health have been inconsistent, and independent effects of correlated pollutants hard to assess. The authors examined effects of NO2on a spectrum of 11 respiratory symptoms, controlling for PM10and SO2, using a large pooled dataset.

Methods:Cross sectional studies were conducted in Russia, Austria, Italy, Switzerland, and the Netherlands, during 1993–99, contributing in total 23 955 children. Study-specific odds ratios for associations with ambient NO2are estimated using logistic regressions with area-level random effects. Heterogeneity between study-specific results, and mean estimates (allowing for heterogeneity) are calculated.

Results:Long term average NO2concentrations were unrelated to prevalences of bronchitis or asthma. Associations were found for sensitivity to inhaled allergens and allergy to pets, with mean odds ratios around 1.14 per 10 μg/m3NO2. SO2had little confounding effect, but an initial association between NO2and morning cough was reduced after controlling for PM10.Associations with reported allergy were not reduced by adjustment for the other pollutants. Odds ratios for allergic symptoms tended to be higher for the 9–12 year old children compared with the 6–8 year old children.

Conclusions:Evidence for associations between NO2and respiratory symptoms was robust only for inhalation allergies. NO2most likely is acting as an indicator of traffic related air pollutants, though its direct effect cannot be ruled out. This remains important, as policies to reduce traffic related air pollution will not result in rapid reductions.
THE CONGLOMERATE DISCOUNT: A NEW EXPLANATION BASED ON CREDIT RISK
Authors: AMMANN MANUEL , VERHOFEN MICHAEL
Published: November 2006

We present a simple new explanation for the diversification discount in the valuation of firms. We demonstrate that, ceteris paribus, limited liability of equity holders is sufficient to explain a diversification discount. To derive this result, we use a credit risk model based on the value of the firm's assets. We show that a conglomerate can be regarded as an option on a portfolio of assets. By splitting up the conglomerate, the investor receives a portfolio of options on assets. The conglomerate discount arises because the value of a portfolio of options is always equal to or higher than the value of an option on a portfolio. The magnitude of the conglomerate discount depends on the number of business units and their correlation, as well as their volatility, among other factors.
PRICING OPTIONS FROM THE POINT OF VIEW OF A TRADER
Authors: STOIKOV SASHA F.
Published: November 2006

This paper is a contribution to the pricing and hedging of options in a market where the volatility is stochastic. The new concept of relative indifference pricing is further developed. This relative price is the price at which an option trader is indifferent to trade in an additional option, given that he is currently holding and dynamically hedging a portfolio of options. We find that the appropriate volatility risk premium depends on the trader's risk aversion coefficient and his portfolio position before selling or buying the additional option. We suggest two asymptotic expansions which relate the volatility risk premium to the Vega of the option portfolio. This approach provides a tool for traders to (i) integrate option pricing with risk management and (ii) quote competitive prices that depend on their aggregate risk exposure.
Mixed Oxides as High-k Gate Dielectric Films
Authors: Luna-Sánchez Rosa María , González-Martínez Ignacio
Published: November 2006

Mixed oxides have become popular high-k gate dielectrics in recent years because they can break thermodynamic limits of the conventional metal oxide material. The addition of a third element into a metal oxide changes its bulk and interfacial layer structures and properties, and therefore, electrical characteristics. In this paper, the author reviews material and electrical properties of mixed oxide high-k materials and discusses possible causes.