bluuebunny/crossref_metadata_2025 huggingface dataset:
The p127 Subunit (DDB1) of the UV-DNA Damage Repair Binding Protein Is Essential for the Targeted Degradation of STAT1 by the V Protein of the Paramyxovirus Simian Virus 5
Authors: Andrejeva J. , Poole E. , Young D. F. , Goodbourn S. , Randall R. E.
Published: October 2002

The V protein of simian virus 5 (SV5) blocks interferon signaling by targeting STAT1 for proteasome-mediated degradation. Here we present three main pieces of evidence which demonstrate that the p127 subunit (DDB1) of the UV damage-specific DNA binding protein (DDB) plays a central role in this degradation process. First, the V protein of an SV5 mutant which fails to target STAT1 for degradation does not bind DDB1. Second, mutations in the N and C termini of V which abolish the binding of V to DDB1 also prevent V from blocking interferon (IFN) signaling. Third, treatment of HeLa/SV5-V cells, which constitutively express the V protein of SV5 and thus lack STAT1, with short interfering RNAs specific for DDB1 resulted in a reduction in DDB1 levels with a concomitant increase in STAT1 levels and a restoration of IFN signaling. Furthermore, STAT1 is degraded in GM02415 (2RO) cells, which have a mutation in DDB2 (the p48 subunit of DDB) which abolishes its ability to interact with DDB1, thereby demonstrating that the role of DDB1 in STAT1 degradation is independent of its association with DDB2. Evidence is also presented which demonstrates that STAT2 is required for the degradation of STAT1 by SV5. These results suggest that DDB1, STAT1, STAT2, and V may form part of a large multiprotein complex which leads to the targeted degradation of STAT1 by the proteasome.
Use of Immunostimulatory Sequence-Containing Oligonucleotides as Topical Therapy for Genital Herpes Simplex Virus Type 2 Infection
Authors: Pyles Richard B. , Higgins Debbie , Chalk Claudia , Zalar Anthony , Eiden Joseph , Brown Carrie , Van Nest Gary , Stanberry Lawrence R.
Published: October 2002

Synthetic oligonucleotides containing CpG motifs in specific sequence contexts have been shown to induce potent immune responses. We have evaluated mucosal administration of two immunostimulatory sequence (ISS)-containing phosphorothioate-stabilized oligonucleotides for antiherpetic efficacy in animal models. The ISS oligonucleotides, suspended in phosphate-buffered saline, were tested in mouse and guinea pig vaginal models of herpes simplex virus type 2 (HSV-2) infection. For comparison, groups of untreated, non-ISS oligonucleotide-treated, and acyclovir-treated animals also were monitored. The results indicated that vaginal epithelial application of ISS (up to 6 h after viral inoculation) with mice lethally challenged with HSV-2 delayed disease onset and reduced the number of animals that developed signs of disease (P= 0.003). ISS application significantly increased survival rates over those of controls (P= 0.0014). The ISS also impacted an established infection in the guinea pig model of HSV-2 disease. A single administration of ISS (21 days after viral inoculation) significantly reduced the frequency and severity of HSV-2 lesions compared to results with non-ISS oligonucleotide-treated and untreated guinea pigs (P< 0.01). HSV-2 is shed from the vaginal cavity of the guinea pig in the absence of lesions, similar to the case with humans. As an additional indication of ISS efficacy, the magnitude of viral shedding also was significantly reduced in ISS-treated animals (P< 0.001). These effects appeared to be immunologically mediated, since ISS had no direct effect on HSV-2 replication in vitro using standard plaque assays. These data suggest that ISS may be useful in the treatment and control of genital herpes in humans.
Effective Postexposure Treatment of Retrovirus-Induced Disease with Immunostimulatory DNA Containing CpG Motifs
Authors: Olbrich Anke R. M. , Schimmer Simone , Heeg Klaus , Schepers Koen , Schumacher Ton N. M. , Dittmer Ulf
Published: October 2002

Therapeutic strategies for the treatment of acute retroviral infections have relied mainly on antiviral drugs. In this study we used the Friend virus model system to demonstrate that enhancement of the immune system can also have dramatic therapeutic effects. Since resistance to Friend virus-induced leukemia in mice is associated with T helper cell type 1 (Th1) immune responses, we enhanced these responses in susceptible mice by treatment with synthetic oligodeoxynucleotides containing unmethylated CpG motifs (CpG-ODN). Treatments begun at 4 days postinfection increased recovery from 6% in the control group to 74% in the CpG-treated group. CpG-mediated recovery was associated with a significant reduction of viral loads in the blood and spleens of treated mice compared to those of control animals. The treatment promoted Th1-type cytokine production by splenocytes of Friend virus-infected mice and augmented Friend virus-specific cytotoxic T-cell responses, but no influence on the virus-specific neutralizing antibody response was observed. Friend virus-specific CD8+T cells were critical for effective treatment with CpG-ODN, since in vivo depletion of these cells from treated mice prevented their recovery. Our results demonstrate that CpG-ODN therapy can significantly enhance virus-specific cellular immune responses and prevent retrovirus-induced disease. These findings may have implications for antiviral therapy in general.
Tropism of Varicella-Zoster Virus for Human Tonsillar CD4+T Lymphocytes That Express Activation, Memory, and Skin Homing Markers
Authors: Ku Chia-Chi , Padilla Jorge A. , Grose Charles , Butcher Eugene C. , Arvin Ann M.
Published: October 2002

Varicella-zoster virus (VZV) is an alphaherpesvirus with the characteristic neurotropism of this group, but VZV also infects T cells productively and downregulates major histocompatibility complex (MHC) class I expression on infected T cells, as shown in the SCID-hu mouse model. T-cell tropism is likely to be critical for the cell-associated viremia associated with primary VZV infection. In these experiments, we found that VZV infects human tonsillar CD4+T cells in culture, with 15 to 25% being positive for VZV proteins as detected by polyclonal anti-VZV immunoglobulin G (IgG) staining and monitored by flow cytometry analysis. RNA transcripts for VZV gE, a late gene product, were detected in T-cell populations that expressed VZV surface proteins, but not in the VZV-negative cell fraction. Exposure to phorbol myristate acetate resulted in an increase in VZV-positive T cells, indicating that viral DNA was present within these cells and that VZV gene expression could be induced by T-cell activation. By immune scanning electron microscopy, VZV virions were detected in abundance on the surfaces of infected tonsillar T cells. The predominant CD4+T-lymphocyte subpopulations that became infected were activated CD69+T cells with the CD45RA−memory phenotype. Subsets of CD4+T cells that expressed skin homing markers, cutaneous leukocyte antigen, and chemokine receptor 4 were also infected with VZV. By chemotaxis assay, VZV-infected T cells migrated to SDF-1, demonstrating that skin migratory function was intact despite VZV infection. The susceptibility of tonsil T cells to VZV suggests that these cells may be important targets during the initial VZV infection of upper respiratory tract sites. Viral transfer to migrating T cells in the tonsils may facilitate cell-associated viremia, and preferential infection of CD4 T cells that express skin homing markers may enhance VZV transport to cutaneous sites of replication.
Elicitation of Simian Immunodeficiency Virus-Specific Cytotoxic T Lymphocytes in Mucosal Compartments of Rhesus Monkeys by Systemic Vaccination
Authors: Baig Jamal , Levy Daniel B. , McKay Paul F. , Schmitz Joern E. , Santra Sampa , Subbramanian Ramu A. , Kuroda Marcelo J. , Lifton Michelle A. , Gorgone Darci A. , Wyatt Linda S. , Moss Bernard , Huang Yue , Chakrabarti Bimal K. , Xu Ling , Kong Wing-Pui , Yang Zhi-Yong , Mascola John R. , Nabel Gary J. , Carville Angela , Lackner Andrew A. , Veazey Ronald S. , Letvin Norman L.
Published: October 2002

Since most human immunodeficiency virus (HIV) infections are initiated following mucosal exposure to the virus, the anatomic containment or abortion of an HIV infection is likely to require vaccine-elicited cellular immune responses in those mucosal sites. Studying vaccine-elicited mucosal immune responses has been problematic because of the difficulties associated with sampling T lymphocytes from those anatomic compartments. In the present study, we demonstrate that mucosal cytotoxic T lymphocytes (CTL) specific for simian immunodeficiency virus (SIV) and simian HIV can be reproducibly sampled from intestinal mucosal tissue of rhesus monkeys obtained under endoscopic guidance. These lymphocytes recognize peptide-major histocompatibility complex class I complexes and express gamma interferon on exposure to peptide antigen. Interestingly, systemic immunization of monkeys with plasmid DNA immunogens followed by live recombinant attenuated poxviruses or adenoviruses with genes deleted elicits high-frequency SIV-specific CTL responses in these mucosal tissues. These studies therefore suggest that systemic delivery of potent HIV immunogens may suffice to elicit substantial mucosal CTL responses.
Adenovirus-Facilitated Nuclear Translocation of Adeno-Associated Virus Type 2
Authors: Xiao Wu , Warrington Kenneth H. , Hearing Patrick , Hughes Jeffrey , Muzyczka Nicholas
Published: October 2002

We examined cytoplasmic trafficking and nuclear translocation of adeno-associated virus type 2 (AAV) by using Alexa Fluor 488-conjugated wild-type AAV, A20 monoclonal antibody immunocytochemistry, and subcellular fractionation techniques followed by DNA hybridization. Our results indicated that in the absence of adenovirus (Ad), AAV enters the cell rapidly and escapes from early endosomes with a
t
1/2
of about 10 min postinfection. Cytoplasmically distributed AAV accumulated around the nucleus and persisted perinuclearly for 16 to 24 h. Viral uncoating occurred before or during nuclear entry beginning about 12 h postinfection, when viral protein and DNA were readily detected in the nucleus. Few, if any, intact AAV capsids were found in the nucleus. In the presence of Ad, however, cytoplasmic AAV quickly translocated into the nucleus as intact particles as early as 40 min after coinfection, and this facilitated nuclear translocation of AAV was not blocked by the nuclear pore complex inhibitor thapsigargan. The rapid nuclear translocation of intact AAV capsids in the presence of Ad suggested that one or more Ad capsid proteins might be altering trafficking. Indeed, coinfection with empty Ad capsids also resulted in the appearance of AAV DNA in nuclei within 40 min. Escape from early endosomes did not seem to be affected by Ad coinfection.
Cell-Type-Specific Characteristics Modulate the Transduction Efficiency of Adeno-Associated Virus Type 2 and Restrain Infection of Endothelial Cells
Authors: Pajusola Katri , Gruchala Marcin , Joch Hana , Lüscher Thomas F. , Ylä-Herttuala Seppo , Büeler Hansruedi
Published: October 2002

Adeno-associated viruses (AAVs) are promising vectors for various gene therapy applications due to their long-lasting transgene expression and wide spectrum of target cells. Recently, however, it has become apparent that there are considerable differences in the efficiencies of transduction of different cell types by AAVs. Here, we analyzed the efficiencies of transduction and the transport mechanisms of AAV type 2 (AAV-2) in different cell types, emphasizing endothelial cells. Expression analyses in both cultured cells and the rabbit carotid artery assay showed a remarkably low level of endothelial cell transduction in comparison to the highly permissive cell types. The study of the endosomal pathways of AAV-2 with fluorescently labeled virus showed clear targeting of the Golgi area in permissive cell lines, but this phenomenon was absent in the endothelial cell line EAhy-926. On the other hand, the response to the block of endosomal acidification by bafilomycin A1 also showed differences among the permissive cell types. We also analyzed the effect of proteasome inhibitors on endothelial cells, but their impact on the primary cells and in vivo was not significant. On the contrary, analysis of the expression pattern of heparan sulfate proteoglycans (HSPGs), the primary receptors of AAV-2, revealed massive deposits of HSPG in the extracellular matrix of endothelial cells. The matrix-associated receptors may therefore compete for virus binding and reduce transduction in endothelial cells. Accordingly, in endothelial cells detached from their matrix, AAV-2 transduction was significantly increased. Altogether, these results point to a more complex cell-type-specific mode of transduction of AAV-2 than previously appreciated.
Alpha/Beta Interferon and Gamma Interferon Synergize To Inhibit the Replication of Herpes Simplex Virus Type 1
Authors: Sainz Bruno , Halford William P.
Published: October 2002

In vivo evidence suggests that T-cell-derived gamma interferon (IFN-γ) can directly inhibit the replication of herpes simplex virus type 1 (HSV-1). However, IFN-γ is a weak inhibitor of HSV-1 replication in vitro. We have found that IFN-γ synergizes with the innate IFNs (IFN-α and -β) to potently inhibit HSV-1 replication in vitro and in vivo. Treatment of Vero cells with either IFN-β or IFN-γ inhibits HSV-1 replication by <20-fold, whereas treatment with both IFN-β and IFN-γ inhibits HSV-1 replication by ∼1,000-fold. Treatment with IFN-β and IFN-γ does not prevent HSV-1 entry into Vero cells, and the inhibitory effect can be overcome by increasing the multiplicity of HSV-1 infection. The capacity of IFN-β and IFN-γ to synergistically inhibit HSV-1 replication is not virus strain specific and has been observed in three different cell types. For two of the three virus strains tested, IFN-β and IFN-γ inhibit HSV-1 replication with a potency that approaches that achieved by a high dose of acyclovir. Pretreatment of mouse eyes with IFN-β and IFN-γ reduces HSV-1 replication to nearly undetectable levels, prevents the development of disease, and reduces the latent HSV-1 genome load per trigeminal ganglion by ∼200-fold. Thus, simultaneous activation of IFN-α/β receptors and IFN-γ receptors appears to render cells highly resistant to the replication of HSV-1. Because IFN-α or IFN-β is produced by most cells as an innate response to virus infection, the results imply that IFN-γ secreted by T cells may provide a critical second signal that potently inhibits HSV-1 replication in vivo.
Immunization of Macaques with Formalin-Inactivated Respiratory Syncytial Virus (RSV) Induces Interleukin-13-Associated Hypersensitivity to Subsequent RSV Infection
Authors: de Swart Rik L. , Kuiken Thijs , Timmerman Helga H. , Amerongen Geert van , van den Hoogen Bernadette G. , Vos Helma W. , Neijens Herman J. , Andeweg Arno C. , Osterhaus Albert D. M. E.
Published: October 2002

Respiratory syncytial virus (RSV) is a major cause of severe respiratory disease in infants and the elderly. RSV vaccine development has been hampered by results of clinical trials in the 1960s, when formalin-inactivated whole-RSV preparations adjuvated with alum (FI-RSV) were found to predispose infants for enhanced disease following subsequent natural RSV infection. We have reproduced this apparently immunopathological phenomenon in infant cynomolgus macaques and identified immunological and pathological correlates. Vaccination with FI-RSV induced specific virus-neutralizing antibody responses accompanied by strong lymphoproliferative responses. The vaccine-induced RSV-specific T cells predominantly produced the Th2 cytokines interleukin-13 (IL-13) and IL-5. Intratracheal challenge with a macaque-adapted wild-type RSV 3 months after the third vaccination elicited a hypersensitivity response associated with lung eosinophilia. The challenge resulted in a rapid boosting of IL-13-producing T cells in the FI-RSV-vaccinated animals but not in the FI-measles virus-vaccinated control animals. Two out of seven FI-RSV-vaccinated animals died 12 days after RSV challenge with pulmonary hyperinflation. Surprisingly, the lungs of these two animals did not show overt inflammatory lesions. However, upon vaccination the animals had shown the strongest lymphoproliferative responses associated with the most pronounced Th2 phenotype within their group. We hypothesize that an IL-13-associated asthma-like mechanism resulted in airway hyperreactivity in these animals. This nonhuman primate model will be an important tool to assess the safety of nonreplicating candidate RSV vaccines.
Role of Cholesterol in Human Immunodeficiency Virus Type 1 Envelope Protein-Mediated Fusion with Host Cells
Authors: Viard Mathias , Parolini Isabella , Sargiacomo Massimo , Fecchi Katia , Ramoni Carlo , Ablan Sherimay , Ruscetti Francis W. , Wang Ji Ming , Blumenthal Robert
Published: October 2002

In this study we examined the effects of target membrane cholesterol depletion and cytoskeletal changes on human immunodeficiency virus type 1 (HIV-1) Env-mediated membrane fusion by dye redistribution assays. We found that treatment of peripheral blood lymphocytes (PBL) with methyl-β-cyclodextrin (MβCD) or cytochalasin reduced their susceptibility to membrane fusion with cells expressing HIV-1 Env that utilize CXCR4 or CCR5. However, treatment of human osteosarcoma (HOS) cells expressing high levels of CD4 and coreceptors with these agents did not affect their susceptibility to HIV-1 Env-mediated membrane fusion. Removal of cholesterol inhibited stromal cell-derived factor-1α- and macrophage inflammatory protein 1β-induced chemotaxis of both PBL and HOS cells expressing CD4 and coreceptors. The fusion activity as well as the chemotactic activity of PBL was recovered by adding back cholesterol to these cells. Confocal laser scanning microscopy analysis indicated that treatment of lymphocytes with MβCD reduced the colocalization of CD4 or of CXCR4 with actin presumably in microvilli. These findings indicate that, although cholesterol is not required for HIV-1 Env-mediated membrane fusion per se, its depletion from cells with relatively low coreceptor densities reduces the capacity of HIV-1 Env to engage coreceptor clusters required to trigger fusion. Furthermore, our results suggest that coreceptor clustering may occur in microvilli that are supported by actin polymerization.
Identification of Second-Site Mutations That Enhance Release and Spread of Vaccinia Virus
Authors: Katz Ehud , Wolffe Elizabeth , Moss Bernard
Published: October 2002

The spread of most strains of vaccinia virus in cell monolayers occurs predominantly via extracellular enveloped virions that adhere to the tips of actin-containing microvilli and to a lesser extent via diffusion of released virions. The mechanism by which virions adhere to the cell surface is unknown, although several viral proteins may be involved. The present investigation was initiated with the following premise: spontaneous mutations that increase virus release will be naturally selected by propagating a virus unable to spread by means of actin tails. Starting with an A36R deletion mutant that forms small, round plaques, five independent virus clones with enhanced spread due to the formation of comet or satellite plaques were isolated. The viral membrane glycoprotein genes of the isolates were sequenced; four had mutations causing C-terminal truncations of the A33R protein, and one had a serine replacing proline 189 of the B5R protein. The comet-forming phenotype was specifically reproduced or reversed by homologous recombination using DNA containing the mutated or natural sequence, respectively. Considerably more extracellular enveloped virus was released into the medium by the second-site mutants than by the parental A36R deletion mutant, explaining their selection in tissue culture as well as their comet-forming phenotype. The data suggest that the B5R protein and the C-terminal region of the A33R protein are involved in adherence of cell-associated enveloped virions to cells. In spite of their selective advantage in cultured cells, the second-site mutants were not detectably more virulent than the A36R deletion mutant when administered to mice by the intranasal route.
Placement of the Structural Proteins in Sindbis Virus
Authors: Zhang Wei , Mukhopadhyay Suchetana , Pletnev Sergei V. , Baker Timothy S. , Kuhn Richard J. , Rossmann Michael G.
Published: October 2002

The structure of the lipid-enveloped Sindbis virus has been determined by fitting atomic resolution crystallographic structures of component proteins into an 11-Å resolution cryoelectron microscopy map. The virus has
T
=4 quasisymmetry elements that are accurately maintained between the external glycoproteins, the transmembrane helical region, and the internal nucleocapsid core. The crystal structure of the E1 glycoprotein was fitted into the cryoelectron microscopy density, in part by using the known carbohydrate positions as restraints. A difference map showed that the E2 glycoprotein was shaped similarly to E1, suggesting a possible common evolutionary origin for these two glycoproteins. The structure shows that the E2 glycoprotein would have to move away from the center of the trimeric spike in order to expose enough viral membrane surface to permit fusion with the cellular membrane during the initial stages of host infection. The well-resolved E1-E2 transmembrane regions form α-helical coiled coils that were consistent with
T
=4 symmetry. The known structure of the capsid protein was fitted into the density corresponding to the nucleocapsid, revising the structure published earlier.
The Latency-Associated Nuclear Antigen of Kaposi's Sarcoma-Associated Herpesvirus Supports Latent DNA Replication in Dividing Cells
Authors: Hu Jianhong , Garber Alexander C. , Renne Rolf
Published: October 2002

Kaposi's sarcoma-associated herpesvirus (KSHV) is associated with Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease. The latency-associated nuclear antigen (LANA) is a multifunctional protein that is consistently expressed in all KSHV-associated malignancies. LANA interacts with a variety of cellular proteins, including the transcriptional cosuppressor complex mSin3 and the tumor suppressors p53 and Rb, thereby regulating viral and cellular gene expression. In addition, LANA is required for maintenance of the episomal viral DNA during latency in dividing cells. Colocalization studies suggest that LANA tethers the viral genome to chromosomes during mitosis. In support of this model, a specific LANA- binding site has recently been identified within the terminal repeat unit, and a chromatin interaction domain was mapped to a short amino acid stretch within the N-terminal domain of LANA. Epstein-Barr virus nuclear antigen 1 (EBNA-1), a functional homologue of LANA, is also required for genome segregation; in addition, EBNA-1 also supports efficient DNA replication of oriP-containing plasmids. By performing short-term replication assays, we demonstrate here for the first time that de novo synthesis of terminal-repeat (TR)-containing plasmids is highly dependent on the presence of LANA. We map the required
cis
-acting sequences within the TR to a 79-bp region and demonstrate that the DNA-binding domain of LANA is required for this DNA replication activity. Surprisingly, the 233-amino-acid C domain of LANA by itself partially supports replication. Our data show that LANA is a sequence-specific DNA-binding protein that, like EBNA-1, plays an important role in DNA replication and genome segregation. In addition, we show that all necessary
cis
elements for the origin of replication (ori) function are located within a single TR, suggesting that the putative ori of KSHV is different from those of other gammaherpesviruses, which all contain ori sequences within the unique long sequence outside of their TR. This notion is further strengthened by the unique modular structure of the KSHV TR element.
The First HxRxG Motif in Simian Immunodeficiency Virus mac239 Vpr Is Crucial for G
2
/M Cell Cycle Arrest
Authors: Mueller Sandra M. , Lang Sabine M.
Published: October 2002

The highly conserved Vpr protein mediates cell cycle arrest, transcriptional transactivation, and nuclear import of the preintegration complex in human immunodeficiency virus type 1. To identify functional domains in simian immunodeficiency virus (SIV) mac239 Vpr, we mutagenized selected motifs within an α-helical region and two C-terminal HxRxG motifs. All Vpr mutants located to the nucleus. Substitution of four amino acids in the α-helical domain did not interfere with cell cycle arrest, while a single substitution abolished cell cycle arrest function. Mutation of the first HxRxG motif to AxAxA also resulted in loss of cell cycle arrest, while mutation of the second motif had no effect. Interestingly, both Vpr mutants impaired in cell cycle arrest function also showed reduced transactivation of the SIV long terminal repeat, suggesting that arrest of cells at G
2
/M mediates or contributes to transactivation by Vpr.
Unique Characteristics of a Picornavirus Internal Ribosome Entry Site from the Porcine Teschovirus-1 Talfan
Authors: Kaku Yoshihiro , Chard Louisa S. , Inoue Toru , Belsham Graham J.
Published: October 2002

The teschoviruses constitute a recently defined picornavirus genus. Most of the genome sequence of the porcine teschovirus-1 (PTV) Talfan and several other strains is known. We now demonstrate that initiation of protein synthesis occurs at nucleotide (nt) 412 on the PTV Talfan RNA and that nt 1 to 405 contains an internal ribosome entry site (IRES) that functions efficiently in vitro and within mammalian cells. In comparison with other picornavirus IRES elements, the PTV IRES is relatively short and lacks a significant polypyrimidine tract near the 3′ end. Expression of an enterovirus 2A protease, which induces cleavage of eIF4G within the translation initiation complex eIF4F, has little effect on the PTV IRES activity within BHK cells. The PTV IRES has a unique set of properties and represents a new class of picornavirus IRES element.
A Reverse Genetics Approach for Recovery of Recombinant Influenza B Viruses Entirely from cDNA
Authors: Jackson David , Cadman Andrew , Zurcher Thomas , Barclay Wendy S.
Published: October 2002

The recovery of recombinant influenza A virus entirely from cDNA was recently described (9, 19). We adapted the technique for engineering influenza B virus and generated a mutant bearing an amino acid change E116G in the viral neuraminidase which was resistant in vitro to the neuraminidase inhibitor zanamivir. The method also facilitates rapid isolation of single-gene reassortants suitable as vaccine seeds and will aid further investigations of unique features of influenza B virus.
Mutation of Capsid Protein Phosphorylation Sites Abolishes Cauliflower Mosaic Virus Infectivity
Authors: Chapdelaine Yvan , Kirk David , Karsies Aletta , Hohn Thomas , Leclerc Denis
Published: October 2002

The cauliflower mosaic virus (CaMV) capsid protein is derived by bidirectional processing of the precapsid protein (CP56). We expressed several derivatives of CP56 in
Escherichia coli
and used them as substrates for virus-associated kinase and casein kinase II purified from plant cells. Three serine residues located at the N terminus of the mature viral protein CP44 were identified as phosphorylation targets. A mutation of one of them in the viral context had little or no effect on viral infectivity, but a mutation of all three serines abolished infectivity. The mapping of phosphorylation sites in CP44, but not CP39 or CP37, and immunodetection of the Zn finger motif in CP44 and CP39, but not CP37, support the model that CP39 is produced from CP44 by N-terminal processing and CP37 is produced from CP39 by C-terminal processing. We discuss the possible role of phosphorylation in the processing and assembly of CaMV capsid protein.
The Human Cytomegalovirus US10 Gene Product Delays Trafficking of Major Histocompatibility Complex Class I Molecules
Authors: Furman Margo H. , Dey Neelendu , Tortorella Domenico , Ploegh Hidde L.
Published: October 2002

Human cytomegalovirus (HCMV) US10 encodes a glycoprotein that binds to major histocompatibility complex (MHC) class I heavy chains. While expression of US10 delays the normal trafficking of MHC class I molecules out of the endoplasmic reticulum, US10 does not obviously facilitate or inhibit the action of two other HCMV-encoded MHC class I binding proteins, US2 and US11.
Differences in Avidity and Epitope Recognition of CD8+T Cells Infiltrating the Central Nervous Systems of SJL/J Mice Infected with BeAn and DA Strains of Theiler's Murine Encephalomyelitis Virus
Authors: Kang Bong-Su , Lyman Michael A. , Kim Byung S.
Published: October 2002

Theiler's murine encephalomyelitis virus (TMEV) infection induces immune-mediated demyelinating disease in susceptible mouse strains and serves as a relevant infectious model for human multiple sclerosis. To investigate the pathogenic mechanisms, two strains of TMEV (DA and BeAn), capable of inducing chronic demyelination in the central nervous system (CNS), have primarily been used. Here, we have compared the T-cell responses induced after infection with DA and BeAn strains in highly susceptible SJL/J mice. CD4+T-cell responses to known epitopes induced by these two strains were virtually identical. However, the CD8+T-cell response induced following DA infection in susceptible SJL/J mice was unable to recognize two of three H-2Ks-restricted epitope regions of BeAn, due to single-amino-acid substitutions. Interestingly, T cells specific for the H-2Ks-restricted epitope (VP111-20) recognized by both strains showed a drastic increase in frequency as well as avidity after infection with DA virus. These results strongly suggest that the level and avidity of virus-specific CD8+T cells infiltrating the CNS could be drastically different after infection with these two strains of TMEV and may differentially influence the pathogenic and/or protective outcome.
Induced Technical Change in Energy and Environmental Modeling: Analytic Approaches and Policy Implications
Authors: Grubb Michael , Köhler Jonathan , Anderson Dennis
Published: October 2002

▪ Abstract  Technical change in the energy sector is central for addressing long-term environmental issues, including climate change. Most models of energy, economy, and the environment (E3 models) use exogenous assumptions for this. This is an important weakness. We show that there is strong evidence that technical change in the energy sector is to an important degree induced by market circumstances and expectations and, by implication, by environmental policies such as CO2abatement. We classify the main approaches to modeling such induced technical change and review results with particular reference to climate change. Among models with learning by doing, weak responses are only obtained from models that are highly aggregated (lack technological diversity) and/or that equate rates of return to innovation across sectors. Induced technical change broadens the scope of efficient policies toward mitigation, including not just research and development and aggregated market instruments but a range of sectoral-based policies potentially at divergent marginal costs. Furthermore, to the extent that cleaner technologies induced by mitigation diffuse globally, a positive spillover will result that will tend to offset the substitution-based negative spillover usually hypothesized to result from the migration of polluting industries. Initial explorations suggest that this effect could also be very large.
Observing and Thinking about the Atmosphere
Authors: Goody Richard
Published: October 2002

[Figure: see text]

▪ Abstract  FAUST: Ich fühl's, vergebens hab' ich alle Schätze Des Menschengeists auf mich herbeigerafft, Und wenn ich mich am Ende niedersetze, Quilt innerlich doch keine neue Kraft; Ich bin nicht um ein Haar breit höher, Bin dem Unendlichen nicht näher. Goethe's Faust, Part I, lines 1810–15. 1

A dedication to research in the physical sciences together with the circumstances of World War II, led me into theoretical and observational studies of the global physical climate. For all practical purposes, I was on my own when working in Cambridge and London, England, and I went whereever my interests led me. I organized three atmospheric observatories (two in England). I have also worked at many astronomical observatories. As time progressed, I became increasingly involved in studies of atmospheric radiation as a controlling factor for the Earth's climate. I am often taken to be a specialist in atmospheric radiation, but I have never regarded it as more than an important element in climate studies.

But radiative transfer and global questions did not become important for climate science until later, and in the 1950s and 1960s I found myself drawn to studies of planetary atmospheres as an arena in which my skills were of central importance. Mars and Venus were the focus of my work for many years, and I was partly responsible for launching the Pioneer Venus mission, which placed probes into the Venus atmosphere in 1978. Much later, the experience I gained in space instrumentation and in the structure of atmospheres led me back to climate science, where I started. Then my interest was in observing the climate and testing the credibility of climate predictions. I still maintain some activity in this field.

Outside these research activities, I created a Center for Earth and Planetary Physics at Harvard University to take over the activities of the Blue Hill Observatory, when that Observatory ceased to be a viable facility. The purpose of the Center was to teach earth science in the context of the discipline of physical science. The Center had some notable achievements but eventually had to give way to requirements for environmental sciences in the University, a change that I regret.

During my active life in the United States, I invested a great deal of effort in support of the work of the National Research Council (NRC), including many years spent on report review. I am increasingly troubled by the postmodern view of science that appears to dominate these activities. But that may be no more than a biased rosy view of the past with its exciting early experiences and hopes.
Urban Air Pollution in China: Current Status, Characteristics, and Progress
Authors: He Kebin , Huo Hong , Zhang Qiang
Published: October 2002

▪ Abstract  China is rapidly developing as evidenced by enhanced urbanization and industrialization and greatly increased energy consumption. However, these have brought Chinese cities a variety of urban air pollution problems in recent decades. During the 1970s, black smoke from stacks became the characteristic of Chinese industrial cities; in the 1980s, many southern cities began to suffer serious acid rain pollution; and recently, the air quality in large cities has deteriorated due to nitrous oxides (NOx), carbon monoxide (CO), and photochemical smog, which are typical of vehicle pollution. Some cities now have a mixture of these. Urban air pollution influences both the health of citizens and the development of cities. To control air pollution and protect the atmospheric environment, the Chinese government has implemented a variety of programs. This paper first reviews the current status of air quality in Chinese cities, especially key cities, then describes the characteristics of some major urban air pollutants, including total suspended particles (TSP), respirable particles 10 microns or less in diameter (PM10), very fine particles 2.5 microns or less in diameter (PM2.5), sulfur dioxide (SO2), acid rain, NOx, and photochemical smog. Two specific topics, SO2 and acid rain control and vehicle emission control, are used to illustrate the actions that the government has taken and future plans. Finally, a case study of the Chinese capital, Beijing, is presented with a discussion of its main air pollution problems, recently implemented control measures and their effects, and future strategies for urban air quality improvement.
An Intellectual History of Environmental Economics
Authors: Pearce David
Published: October 2002

▪ Abstract  From modest beginnings in the 1960s, environmental economics has grown to be a major subdiscipline of economics. It combines traditional work in the field of welfare economics and the theory of economic growth with more recent perspectives on the political economy of choosing policy instruments and the philosophy of sustainable development. The central tenets are that environmental problems have their roots in the failure of economic systems to maximize human well-being, that environmental quality matters for human well-being and for more traditionally oriented economic growth objectives, and that efficient policy can be achieved through incentive design.
Household Energy, Indoor Air Pollution, and Health in Developing Countries: Knowledge Base for Effective Interventions
Authors: Ezzati Majid , Kammen Daniel M.
Published: October 2002

▪ Abstract  Globally, almost three billion people rely on biomass (wood, charcoal, crop residues, and dung) and coal as their primary source of domestic energy. Exposure to indoor air pollution from the combustion of solid fuels is an important cause of disease and mortality in developing countries. Despite recent advances in estimating the health impacts of indoor smoke, there are limited studies targeted toward the design and implementation of effective intervention programs. We review the current knowledge of the relationship between indoor air pollution and disease, and of the assessment of interventions for reducing exposure and disease. This review takes an environmental health perspective and considers the details of both exposure and health effects that are needed for successful intervention strategies. In particular, we summarize the emerging understanding of the central role of household energy technology and day-to-day household activities in determining exposure to indoor smoke. We also identify knowledge gaps and detailed research questions that are essential in successful design and dissemination of preventive measures and policies. In addition to specific research recommendations based on the weight of recent studies, we conclude that research and development of effective interventions can benefit tremendously from integration of methods and analysis tools from a range of disciplines—from quantitative environmental science and engineering, to toxicology and epidemiology, to the social sciences.
Evolution of the Indian Nuclear Power Program
Authors: Gopalakrishnan A.
Published: October 2002

▪ Abstract  Presently, India occupies a leading place among Asian nations in the indigenous design, development, construction, and operation of nuclear power reactors. Nuclear power generation in India is based on a three-stage plan to eventually make use of the abundant national resources of thorium, through the use of fast breeder reactors. To achieve this long-range goal, India had to necessarily start with setting up heavy water–moderated, natural uranium–fueled power reactors to produce the plutonium required for the subsequent stages. But, as a result of India's nuclear weapon test in 1974, the developed nations imposed a comprehensive ban on the export of nuclear materials and technology to India, and these sanctions are still in force. This article outlines the steps followed by India to successfully counter these sanctions over the last 25 years and presents a critical evaluation of the potential problems and prospects of nuclear power in India.
Sorry, Wrong Number: The Use and Misuse of Numerical Facts in Analysis and Media Reporting of Energy Issues
Authors: Koomey Jonathan G. , Calwell Chris , Laitner Skip , Thornton Jane , Brown Richard E. , Eto Joseph H. , Webber Carrie , Cullicott Cathy
Published: October 2002

▪ Abstract  Students of public policy sometimes envision an idealized policy process where competent data collection and incisive analysis on both sides of a debate lead to reasoned judgments and sound decisions. Unfortunately, numbers that prove decisive in policy debates are not always carefully developed, credibly documented, or correct. This paper presents four widely cited examples of numbers in the energy field that are either misleading or wrong. It explores the origins of these numbers, how they missed the mark, and how they have been misused by both analysts and the media. In addition, it describes and uses a three-stage analytical process for evaluating such statistics that involves defining terms and boundaries, assessing underlying data, and critically analyzing arguments.
Oil resistance controlled by phase morphology in natural rubber/nitrile rubber blends
Authors: Sirisinha Chakrit , Limcharoen Sauvarop , Thunyarittikorn Jarunee
Published: November 2002

Rheological properties, morphology, and oil resistance in natural rubber (NR)/nitrile rubber (NBR) blends were investigated as functions of blending conditions and viscosity ratios of the blends. As for the blending condition effects, Mooney viscosity of the blends depended more strongly on blending time than rotor speed. Size of the NR dispersed phase was approximately independent of rotor speed but decreased with increasing blending time up to 25 min. As blending time further increased, NR dispersed phase size increased. The results of relative tensile strength, which is an indicator for oil resistance, in this study were in agreement with those of the blend morphology, indicating that the oil resistance in 20/80 NR/NBR blend depended strongly on the phase morphology of the blend. The smaller the size of NR dispersed phase was, the higher was the resistance to oil of the blend. However, a decrease in the size of the dispersed phase by the modification of the viscosity ratio via the use of low‐molecular‐weight rubber (i.e., liquid natural rubber and epoxidized liquid natural rubber) did not result in an improvement in the oil resistance. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 83–89, 2003
Rubber biosynthesis by a Hevea latex bottom‐fraction membrane
Authors: Wititsuwannakul Dhirayos , Rattanapittayaporn Atiya , Wititsuwannakul Rapepun
Published: November 2002

Washed bottom‐fraction particles (WBPs), that is, intact membrane‐bound vesicles, prepared from the bottom fraction of centrifuged fresh latex, were shown to be active in in vitro rubber biosynthesis (RB) assays. The RB activity catalyzed by WBP enzymes was confirmed by enzyme parameter criteria. A washed bottom‐fraction particle membrane (WBM), prepared from WBPs, was even more active in in vitro RB activity. Mg2+ was a cofactor required for RB enzymes, and the cation chelators EDTA and EGTA inhibited the RB process. The temperature had a strong effect on RB stimulation during the heat pretreatment of the WBM before RB assays. A detergent also proved to a strong RB stimulator. The anionic detergent SDS, above the critical micelle concentration, was a strong stimulator of WBM activity. This was not observed with the nonionic detergents Triton X‐100 and Tween 20. Various temperature ranges used for WBM preincubation showed a sharp rise in RB activity above 70°C. The temperature required for a sharp rise in RB was lowered substantially in the presence of SDS. It was down to 40°C with the combined preincubation but remained constant with an even higher RB activity. Greater rubber formation at a lower temperature was observed in the presence of SDS. A synergistic effect for RB stimulation appeared during the heat pretreatment of WBM in the presence of SDS. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 90–96, 2003
Cell‐surface expression and immune receptor recognition of HLA–B27 homodimers
Authors: Kollnberger Simon , Bird Lucy , Sun Mei‐Yi , Retiere Christelle , Braud Veronique M. , McMichael Andrew , Bowness Paul
Published: November 2002

Objective

HLA–B27 is capable of forming in vitro a heavy‐chain homodimer structure lacking β2‐microglobulin. We undertook this study to ascertain if patients with spondylarthritis express β2‐microglobulin–free HLA–B27 heavy chains in the form of homodimers and receptors for HLA–B27 homodimers.

Methods

Expression of HLA–B27 heavy chains by mononuclear cells was analyzed by fluorescence‐activated cell sorter staining, Western blotting with the monoclonal antibody HC‐10, and 2‐dimensional isoelectric focusing. Fluorescence‐labeled tetrameric complexes of HLA–B27 heavy‐chain homodimers were constructed in which each dimer comprised one His‐tagged heavy chain and one biotinylated heavy chain, and were used to stain patient and control mononuclear cells and transfected cell lines.

Results

Patients with spondylarthritis expressed cell‐surface HLA–B27 homodimers. Populations of synovial and peripheral blood monocytes, and B and T lymphocytes from patients with spondylarthritis, and controls carried receptors for HLA–B27 homodimers. Experiments with transfected cell lines demonstrated that KIR3DL1 and KIR3DL2, and immunoglobulin‐like transcript 4 (ILT4), but not ILT2, are receptors for HLA–B27 homodimers.

Conclusion

Patients with spondylarthritis express both HLA–B27 heavy‐chain homodimers and receptors for HLA–B27 homodimers. This may be of significance with regard to disease pathogenesis.
Safe disposal of inflammatory monosodium urate monohydrate crystals by differentiated macrophages
Authors: Landis R. Clive , Yagnik Darshna R. , Florey Oliver , Philippidis Pandelis , Emons Vivien , Mason Justin C. , Haskard Dorian O.
Published: November 2002

Objective

Although monosodium urate monohydrate (MSU) crystals have been recognized since the 18th century as the etiologic agent of gout, it is still unknown why certain hyperuricemic individuals remain asymptomatic, and how an acute attack of gout spontaneously resolves. We hypothesized that mononuclear phagocytes hold the key to these questions, and that the state of monocyte/macrophage differentiation is critical.

Methods

Human peripheral blood monocytes were differentiated for 1–7 days in vitro and examined with respect to 1) uptake of MSU crystals, 2) expression of macrophage, dendritic cell, and activation markers, 3) secretion of tumor necrosis factor α (TNFα), interleukin 1β (IL‐1β), IL‐6, and IL‐10, 4) activation of endothelial E‐selectin expression, and 5) enhancement of secondary neutrophil recruitment by endothelial cells.

Results

MSU crystals induced TNFα, IL‐1β, and IL‐6 (but not IL‐10) secretion in undifferentiated monocytes, which in turn promoted endothelial cell E‐selectin expression and secondary neutrophil capture under shear flow. In contrast, differentiation over 3–5 days led to development of a noninflammatory phenotype characterized by a lack of proinflammatory cytokine secretion, lack of endothelial cell activation, and lack of secondary neutrophil recruitment. Acquisition of the noninflammatory phenotype correlated with expression of macrophage antigen but not with expression of dendritic cell marker or activation marker. Monocytes and macrophages were similarly phagocytic, and a control particle, zymosan, elicited secretion of the full panel of cytokines in both cell types. However, coincubation with MSU led to a significant suppression of zymosan‐induced TNFα secretion (P = 0.009) from macrophages but not monocytes.

Conclusion

These findings imply that differentiated macrophages provide a safe‐disposal mechanism for the removal of inflammatory urate crystals. This may be of clinical relevance to the maintenance of asymptomatic hyperuricemia and the resolution of acute gout.
HR‐DOSY as a new tool for the study of chemical exchange phenomena
Authors: Cabrita Eurico J. , Berger Stefan
Published: November 2002

DOSY NMR spectroscopy can be a fast and easy method to establish qualitatively the relative order of magnitude of the exchange rates of systems in slow exchange in chemical shift. By measuring a series of DOSY spectra of a two‐site exchange system, where exchange occurs between sites with different diffusion coefficients, we show that by increasing the diffusion time among experiments it is possible to extract information about the relative exchange rates of protons with the bulk solvent and therefore infer their solvent accessibility. Copyright © 2002 John Wiley & Sons, Ltd.