bluuebunny/crossref_metadata_2025 huggingface dataset:
Sunlight in Your Tank—Right Away
Authors: Service Robert F.
Published: November 2011

Some researchers are looking to use artificial photosynthesis to generate hydrocarbon fuels like those we already burn. Their goal is essentially to run combustion in reverse.
Targeting Chaperone-Mediated Autophagy in Cancer
Authors: Thorburn Andrew , Debnath Jayanta
Published: November 2011

Tumors need chaperone-mediated autophagy for growth and metastasis.
Optimized Adenovirus-Antibody Complexes Stimulate Strong Cellular and Humoral Immune Responses against an Encoded Antigen in Naïve Mice and Those with Preexisting Immunity
Authors: Choi Jin Huk , Dekker Joe , Schafer Stephen C. , John Jobby , Whitfill Craig E. , Petty Christopher S. , Haddad Eid E. , Croyle Maria A.
Published: November 2011

The immune response to recombinant adenoviruses is the most significant impediment to their clinical use for immunization. We test the hypothesis that specific virus-antibody combinations dictate the type of immune response generated against the adenovirus and its transgene cassette under certain physiological conditions while minimizing vector-induced toxicity.In vitroandin vivoassays were used to characterize the transduction efficiency, the T and B cell responses to the encoded transgene, and the toxicity of 1 × 1011adenovirus particles mixed with different concentrations of neutralizing antibodies. Complexes formed at concentrations of 500 to 0.05 times the 50% neutralizing dose (ND50) elicited strong virus- and transgene-specific T cell responses. The 0.05-ND50formulation elicited measurable anti-transgene antibodies that were similar to those of virus alone (P= 0.07). This preparation also elicited very strong transgene-specific memory T cell responses (28.6 ± 5.2% proliferation versus 7.7 ± 1.4% for virus alone). Preexisting immunity significantly reduced all responses elicited by these formulations. Although lower concentrations (0.005 and 0.0005 ND50) of antibody did not improve cellular and humoral responses in naïve animals, they did promote strong cellular (0.005 ND50) and humoral (0.0005 ND50) responses in mice with preexisting immunity. Some virus-antibody complexes may improve the potency of adenovirus-based vaccines in naïve individuals, while others can sway the immune response in those with preexisting immunity. Additional studies with these and other virus-antibody ratios may be useful to predict and model the type of immune responses generated against a transgene in those with different levels of exposure to adenovirus.
Development of a Multiplex PCR Assay for Detection and Genogrouping of Neisseria meningitidis
Authors: Zhu Hongfei , Wang Quan , Wen Liuqing , Xu Jianguo , Shao Zhujun , Chen Min , Chen Mingliang , Reeves Peter R. , Cao Boyang , Wang Lei
Published: November 2011

Neisseria meningitidis
is a leading pathogen of epidemic bacterial meningitis and fulminant sepsis worldwide. Twelve different
N. meningitidis
serogroups have been identified to date based on antigenic differences in the capsular polysaccharide. However, more than 90% of human cases of
N. meningitidis
meningitis are the result of infection with just five serogroups, A, B, C, W135, and Y. Efficient methods of detection and genogrouping of
N. meningitidis
isolates are needed, therefore, in order to monitor prevalent serogroups as a means of disease control and prevention. The capsular gene complex regions have been sequenced from only seven out of the 12 serogroups. In this study, the capsular gene complexes of the remaining five serogroups were sequenced and analyzed. Primers were designed that were specific for
N. meningitidis
species and for the 12 individual serogroups, and a multiplex PCR assay using these specific primers was developed for
N. meningitidis
detection and genogrouping. The assay was tested using 15 reference strains covering all 12 serogroups, 143 clinical isolates, and 21 strains from closely related species or from species that cause meningitis. The assay could detect
N. meningitidis
serogroups and was shown to be specific, with a detection sensitivity of 1 ng of genomic DNA (equivalent to ∼4 × 10
5
genomes) or 3 × 10
5
CFU/ml in noncultured mock cerebrospinal fluid (CSF) specimens. This study, therefore, describes for the first time the development of a molecular protocol for the detection of all
N. meningitidis
serogroups. This multiplex PCR-based assay may have use for the clinical diagnosis and epidemiological surveillance of
N. meningitidis
.
Validation of
pncA
Gene Sequencing in Combination with the Mycobacterial Growth Indicator Tube Method To Test Susceptibility of Mycobacterium tuberculosis to Pyrazinamide
Authors: Simons Sami O. , van Ingen Jakko , van der Laan Tridia , Mulder Arnout , Dekhuijzen P. N. Richard , Boeree Martin J. , van Soolingen Dick
Published: November 2011

Pyrazinamide is important in the treatment of tuberculosis. Unfortunately, the diagnosis of pyrazinamide resistance is hampered by technical difficulties. We hypothesized that mutation analysis combined with the mycobacterial growth indicator tube (MGIT) phenotypic method would be a good predictor of pyrazinamide resistance. We prospectively analyzed 1,650
M. tuberculosis
isolates referred to our tuberculosis reference laboratory in 2008 and 2009. In our laboratory, the MGIT 960 system was used for pyrazinamide resistance screening. If a pyrazinamide-resistant strain was detected, we performed a
pncA
gene mutation analysis. A second MGIT 960 susceptibility assay was performed afterwards to evaluate the accuracy of the
pncA
mutation analysis to detect true- or false-positive MGIT results. We observed pyrazinamide resistance in 69 samples using the first MGIT 960 analysis. In a second MGIT 960 analysis, 47 of the 69 samples proved susceptible (68% false positivity). Sensitivity of nonsynonymous
pncA
mutations for detecting resistant isolates was 73% (95% confidence interval [CI], 61% to 73%), and specificity was 100% (95% CI, 95% to 100%). A diagnostic algorithm incorporating phenotypic and molecular methods would have a 100% positive predictive value for detecting pyrazinamide-resistant isolates, indicating that such an algorithm, based on both methods, is a good predictor for pyrazinamide resistance in routine diagnostics.
Highly Pathogenic Avian Influenza Virus Subtype H5N1 Escaping Neutralization: More than HA Variation
Authors: Höper Dirk , Kalthoff Donata , Hoffmann Bernd , Beer Martin
Published: November 2011

Influenza A viruses are one of the major threats in modern health care. Novel viruses arise due to antigenic drift and antigenic shift, leading to escape from the immune system and resulting in a serious problem for disease control. In order to investigate the escape process and to enable predictions of escape, we serially passaged influenza A H5N1 virus
in vitro
100 times under immune pressure. The generated escape viruses were characterized phenotypically and in detail by full-genome deep sequencing. Mutations already found in natural isolates were detected, evidencing the
in vivo
relevance of the
in vitro
-induced amino acid substitutions. Additionally, several novel alterations were triggered. Altogether, the results imply that our
in vitro
system is suitable to study influenza A virus evolution and that it might even be possible to predict antigenic changes of influenza A viruses circulating in vaccinated populations.
The Cellular Antiviral Restriction Factor Tetherin Does Not Inhibit Poxviral Replication
Authors: Sliva Katja , Resch Theresa , Kraus Benjamin , Goffinet Christine , Keppler Oliver T. , Schnierle Barbara S.
Published: November 2011

Interferon-stimulated genes fulfill innate antiviral effector functions. Among them, tetherin (THN) blocks the release of many enveloped viruses from infected cells. Vaccinia virus (VACV) encodes immune modulators interfering with antiviral host responses. Therefore, it was tempting to study a potential VACV-THN interaction. Remarkably, THN expression did not inhibit VACV release and replication. VACV infection did not diminish THN surface levels or impair its function on retroviral release. This suggests that THN is unable to restrict VACV replication.
Hepatitis C Virus Fails To Activate NF-κB Signaling in Plasmacytoid Dendritic Cells
Authors: Dental Clélia , Florentin Jonathan , Aouar Besma , Gondois-Rey Francoise , Durantel David , Baumert Thomas F. , Nunes Jacques A. , Olive Daniel , Hirsch Ivan , Stranska Ruzena
Published: November 2011

Plasmacytoid dendritic cells (pDCs) respond to viral infection by production of alpha interferon (IFN-α), proinflammatory cytokines, and cell differentiation. The elimination of hepatitis C virus (HCV) in more than 50% of chronically infected patients by treatment with IFN-α suggests that pDCs can play an important role in the control of HCV infection. pDCs exposed to HCV-infected hepatoma cells, in contrast to cell-free HCV virions, produce large amounts of IFN-α. To further investigate the molecular mechanism of HCV sensing, we studied whether exposure of pDCs to HCV-infected hepatoma cells activates, in parallel to interferon regulatory factor 7 (IRF7)-mediated production of IFN-α, nuclear factor kappa B (NF-κB)-dependent pDC responses, such as expression of the differentiation markers CD40, CCR7, CD86, and tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and secretion of the proinflammatory cytokines TNF-α and interleukin 6 (IL-6). We demonstrate that exposure of pDCs to HCV-infected hepatoma cells surprisingly did not induce phosphorylation of NF-κB or cell surface expression of CD40, CCR7, CD86, or TRAIL or secretion of TNF-α and IL-6. In contrast, CpG-A and CpG-B induced production of TNF-α and IL-6 in pDCs exposed to the HCV-infected hepatoma cells, showing that cell-associated virus did not actively inhibit Toll-like receptor (TLR)-mediated NF-κB phosphorylation. Our results suggest that cell-associated HCV signals in pDCs via an endocytosis-dependent mechanism and IRF7 but not via the NF-κB pathway. In spite of IFN-α induction, cell-associated HCV does not induce a full functional response of pDCs. These findings contribute to the understanding of evasion of immune responses by HCV.
Essential C-Terminal Region of the Baculovirus Minor Capsid Protein VP80 Binds DNA
Authors: Marek Martin , Merten Otto-Wilhelm , Francis-Devaraj Feana , van Oers Monique M.
Published: November 2011

The essential
Autographa californica
multicapsid nucleopolyhedrovirus (AcMNPV) minor capsid protein VP80 has been recently shown to interact with the virus-triggered, nuclear F-actin cytoskeleton. A role for VP80 in virus morphogenesis has been proposed in the maturation of progeny nucleocapsids and in their egress from the virogenic stroma toward the nuclear periphery by a mechanism, which also includes F-actin filaments. We performed functional mapping of VP80 demonstrating that its highly conserved C-terminal region plays a crucial role in virion morphogenesis. Protein database mining identified a putative basic helix-loop-helix (bHLH) domain, a DNA-binding module typical for eukaryotic transcription factors, in the essential C-terminal region of VP80. Using a molecular modeling approach, we predicted the three-dimensional structure of this domain, revealing some unique properties. Biochemical assays proved that VP80 can form homodimers, a critical prerequisite of DNA-binding bHLH proteins. The ability of VP80 to bind DNA was subsequently confirmed by an electrophoretic mobility shift assay. We further show that AcMNPV DNA replication occurs in the absence of VP80. Immunolabeling of VP80 in baculovirus-infected cells rather points toward its involvement in nucleocapsid maturation. The competence of VP80 to interact with both F-actin and DNA provides novel insight into baculovirus morphogenesis.
Bromovirus RNA Replication Compartment Formation Requires Concerted Action of 1a's Self-Interacting RNA Capping and Helicase Domains
Authors: Diaz Arturo , Gallei Andreas , Ahlquist Paul
Published: November 2011

All positive-strand RNA viruses replicate their genomes in association with rearranged intracellular membranes such as single- or double-membrane vesicles. Brome mosaic virus (BMV) RNA synthesis occurs in vesicular endoplasmic reticulum (ER) membrane invaginations, each induced by many copies of viral replication protein 1a, which has N-terminal RNA capping and C-terminal helicase domains. Although the capping domain is responsible for 1a membrane association and ER targeting, neither this domain nor the helicase domain was sufficient to induce replication vesicle formation. Moreover, despite their potential for mutual interaction, the capping and helicase domains showed no complementation when coexpressed in
trans
. Cross-linking showed that the capping and helicase domains each form trimers and larger multimers
in vivo
, and the capping domain formed extended, stacked, hexagonal lattices
in vivo
. Furthermore, coexpressing the capping domain blocked the ability of full-length 1a to form replication vesicles and replicate RNA and recruited full-length 1a into mixed hexagonal lattices with the capping domain. Thus, BMV replication vesicle formation and RNA replication depend on the direct linkage and concerted action of 1a's self-interacting capping and helicase domains. In particular, the capping domain's strong dominant-negative effects showed that the ability of full-length 1a to form replication vesicles was highly sensitive to disruption by non-productively titrating lattice-forming self-interactions of the capping domain. These and other findings shed light on the roles and interactions of 1a domains in replication compartment formation and support prior results suggesting that 1a induces replication vesicles by forming a capsid-like interior shell.
Disassembly of Simian Virus 40 during Passage through the Endoplasmic Reticulum and in the Cytoplasm
Authors: Kuksin Dmitry , Norkin Leonard C.
Published: November 2011

The nonenveloped polyomavirus simian virus 40 (SV40) is taken up into cells by a caveola-mediated endocytic process that delivers the virus to the endoplasmic reticulum (ER). Within the ER lumen, the capsid undergoes partial disassembly, which exposes its internal capsid proteins VP2 and VP3 to immunostaining with antibodies. We demonstrate here that the SV40 genome does not become accessible to detection while the virus is in the ER. Instead, the genome becomes accessible two distinct detection procedures, one using anti-bromodeoxyuridine antibodies and the other using a 5-ethynyl-2-deoxyuridine-based chemical reaction, only after the emergence of partially disassembled SV40 particles in the cytoplasm. These cytoplasmic particles retain some of the SV40 capsid proteins, VP1, VP2, and VP3, in addition to the viral genome. Thus, SV40 particles undergo discrete disassembly steps during entry that are separated temporally and topologically. First, a partial disassembly of the particles occurs in the ER, which exposes internal capsid proteins VP2 and VP3. Then, in the cytoplasm, disassembly progresses further to also make the genomic DNA accessible to immune detection.
Transmembrane Domain Determinants of CD4 Downregulation by HIV-1 Vpu
Authors: Magadán Javier G. , Bonifacino Juan S.
Published: November 2011

The transmembrane domains (TMDs) of integral membrane proteins do not merely function as membrane anchors but play active roles in many important biological processes. The downregulation of the CD4 coreceptor by the Vpu protein of HIV-1 is a prime example of a process that is dependent on specific properties of TMDs. Here we report the identification of Trp22 in the Vpu TMD and Gly415 in the CD4 TMD as critical determinants of Vpu-induced targeting of CD4 to endoplasmic reticulum (ER)-associated degradation (ERAD). The two residues participate in different aspects of ERAD targeting. Vpu Trp22 is required to prevent assembly of Vpu into an inactive, oligomeric form and to promote CD4 polyubiquitination and subsequent recruitment of the VCP-UFD1L-NPL4 dislocase complex. In the presence of a Vpu Trp22 mutant, CD4 remains integrally associated with the ER membrane, suggesting that dislocation from the ER into the cytosol is impaired. CD4 Gly415, on the other hand, contributes to CD4-Vpu interactions. We also identify two residues, Val20 and Ser23, in the Vpu TMD that mediate retention of Vpu and, by extension, CD4 in the ER. These findings highlight the exploitation of several TMD-mediated mechanisms by HIV-1 Vpu in order to downregulate CD4 and thus promote viral pathogenesis.
GRB2 Interaction with the Ecotropic Murine Leukemia Virus Receptor, mCAT-1, Controls Virus Entry and Is Stimulated by Virus Binding
Authors: Chen Zeming , Kolokoltsov Andrey A. , Wang Jia , Adhikary Shramika , Lorinczi Marta , Elferink Lisa A. , Davey Robert A.
Published: November 2011

For retroviruses such as HIV-1 and murine leukemia virus (MLV), active receptor recruitment and trafficking occur during viral entry. However, the underlying mechanisms and cellular factors involved in the process are largely uncharacterized. The viral receptor for ecotropic MLV (eMLV), a classical model for retrovirus infection mechanisms and pathogenesis, is mouse cationic amino acid transporter 1 (mCAT-1). Growth factor receptor-bound protein 2 (GRB2) is an adaptor protein that has been shown to couple cell surface receptors, such as epidermal growth factor receptor (EGFR) and hepatocyte growth factor receptor, to intracellular signaling events. Here we examined if GRB2 could also play a role in controlling infection by retroviruses by affecting receptor function. The GRB2 RNA interference (RNAi)-mediated suppression of endogenous GRB2 resulted in a consistent and significant reduction of virus binding and membrane fusion. The binding between eMLV and cells promoted increased GRB2–mCAT-1 interactions, as detected by immunoprecipitation. Consistently, the increased colocalization of GRB2 and mCAT-1 signals was detected by confocal microscopy. This association was time dependent and paralleled the kinetics of cell-virus membrane fusion. Interestingly, unlike the canonical binding pattern seen for GRB2 and growth factor receptors, GRB2–mCAT-1 binding does not depend on the GRB2-SH2 domain-mediated recognition of tyrosine phosphorylation on the receptor. The inhibition of endogenous GRB2 led to a reduction in surface levels of mCAT-1, which was detected by immunoprecipitation and by a direct binding assay using a recombinant MLV envelope protein receptor binding domain (RBD). Consistent with this observation, the expression of a dominant negative GRB2 mutant (R86K) resulted in the sequestration of mCAT-1 from the cell surface into intracellular vesicles. Taken together, these findings suggest a novel role for GRB2 in ecotropic MLV entry and infection by facilitating mCAT-1 trafficking.
The V Protein of Mumps Virus Plays a Critical Role in Pathogenesis
Authors: Xu Pei , Luthra Priya , Li Zhuo , Fuentes Sandra , D'Andrea James Alexander , Wu Jianguo , Rubin Steven , Rota Paul A. , He Biao
Published: November 2011

Mumps virus (MuV) causes an acute infection in humans characterized by a wide array of symptoms ranging from relatively mild manifestations, such as parotitis, to more-severe complications, such as meningitis and encephalitis. Widespread mumps vaccination has reduced mumps incidence dramatically; however, outbreaks still occur in vaccinated populations. The V protein of MuV, when expressed in cell culture, blocks interferon (IFN) expression and signaling and interleukin-6 (IL-6) signaling. In this work, we generated a recombinant MuV incapable of expressing the V protein (rMuVΔV). The rescued MuV was derived from a clinical wild-type isolate from a recent outbreak in the United States (MuV
Iowa/US/06
, G genotype). Analysis of the virus confirmed the roles of V protein in blocking IFN expression and signaling and IL-6 signaling. We also found that the rMuV
Iowa/US/06
ΔV virus induced high levels of IL-6 expression
in vitro
, suggesting that V plays a role in reducing IL-6 expression.
In vivo
, the rMuV
Iowa/US/06
ΔV virus was highly attenuated, indicating that the V protein plays an essential role in viral virulence.
Xpr1 Is an Atypical G-Protein-Coupled Receptor That Mediates Xenotropic and Polytropic Murine Retrovirus Neurotoxicity
Authors: Vaughan Andrew E. , Mendoza Ramon , Aranda Ramona , Battini Jean-Luc , Miller A. Dusty
Published: November 2011

Xenotropic murine leukemia virus-related virus (XMRV) was first identified in human prostate cancer tissue and was later found in a high percentage of humans with chronic fatigue syndrome (CFS). While exploring potential disease mechanisms, we found that XMRV infection induced apoptosis in SY5Y human neuroblastoma cells, suggesting a mechanism for the neuromuscular pathology seen in CFS. Several lines of evidence show that the cell entry receptor for XMRV, Xpr1, mediates this effect, and chemical cross-linking studies show that Xpr1 is associated with the Gβ subunit of the G-protein heterotrimer. The activation of adenylate cyclase rescued the cells from XMRV toxicity, indicating that toxicity resulted from reduced G-protein-mediated cyclic AMP (cAMP) signaling. Some proteins with similarity to Xpr1 are involved in phosphate uptake into cells, but we found no role of Xpr1 in phosphate uptake or its regulation. Our results indicate that Xpr1 is a novel, atypical G-protein-coupled receptor (GPCR) and that xenotropic or polytropic retrovirus binding can disrupt the cAMP-mediated signaling function of Xpr1, leading to the apoptosis of infected cells. We show that this pathway is also responsible for the classic toxicity of the polytropic mink cell focus-forming (MCF) retrovirus in mink cells. Although it now seems clear that the detection of XMRV in humans was the result of sample contamination with a recombinant mouse virus, our findings may have relevance to neurologic disease induced by MCF retroviruses in mice.
Respiratory Syncytial Virus Glycoprotein G Interacts with DC-SIGN and L-SIGN To Activate ERK1 and ERK2
Authors: Johnson Teresa R. , McLellan Jason S. , Graham Barney S.
Published: November 2011

Respiratory syncytial virus (RSV) interaction with epithelial and dendritic cells (DCs) is known to require divalent cations, suggesting involvement of C-type lectins. RSV infection and maturation of primary human DCs are reduced in a dose-dependent manner by EDTA. Therefore, we asked whether RSV infection involves DC-SIGN (CD209) or its isoform L-SIGN (CD299) (DC-SIGN/R). Using surface plasmon resonance analysis, we demonstrated that the attachment G glycoprotein of RSV binds both DC- and L-SIGN. However, neutralization of DC- and L-SIGN on primary human DCs did not inhibit RSV infection, demonstrating that interactions between RSV G and DC- or L-SIGN are not required for productive infection. Thus, neither DC- nor L-SIGN represents a functional receptor for RSV. However, inhibition of these interactions increased DC activation, as evidenced by significantly higher levels of alpha interferon (IFN-α), MIP-1α, and MIP-1β in plasmacytoid DCs (pDCs) exposed to RSV after neutralization of DC-and L-SIGN. To understand the molecular interactions involved, intracellular signaling events triggered by purified RSV G glycoprotein were examined in DC- and L-SIGN-transfected 3T3 cells. RSV G interaction with DC- or L-SIGN was shown to stimulate ERK1 and ERK2 phosphorylation, with statistically significant increases relative to mock-infected cells. Neutralization of DC- and L-SIGN reduced ERK1/2 phosphorylation. With increased DC activation following DC- and L-SIGN neutralization and RSV exposure, these data demonstrate that the signaling events mediated by RSV G interactions with DC/L-SIGN are immunomodulatory and diminish DC activation, which may limit induction of RSV-specific immunity.
HLA-B*57 Micropolymorphism Shapes HLA Allele-Specific Epitope Immunogenicity, Selection Pressure, and HIV Immune Control
Authors: Kloverpris Henrik N. , Stryhn Anette , Harndahl Mikkel , van der Stok Mary , Payne Rebecca P. , Matthews Philippa C. , Chen Fabian , Riddell Lynn , Walker Bruce D. , Ndung'u Thumbi , Buus Søren , Goulder Philip
Published: November 2011

The genetic polymorphism that has the greatest impact on immune control of human immunodeficiency virus (HIV) infection is expression of HLA-B*57. Understanding of the mechanism for this strong effect remains incomplete. HLA-B*57 alleles and the closely related HLA-B*5801 are often grouped together because of their similar peptide-binding motifs and HIV disease outcome associations. However, we show here that the apparently small differences between HLA-B*57 alleles, termed HLA-B*57 micropolymorphisms, have a significant impact on immune control of HIV. In a study cohort of >2,000 HIV C-clade-infected subjects from southern Africa, HLA-B*5703 is associated with a lower viral-load set point than HLA-B*5702 and HLA-B*5801 (medians, 5,980, 15,190, and 19,000 HIV copies/ml plasma;P= 0.24 andP= 0.0005). In order to better understand these observed differences in HLA-B*57/5801-mediated immune control of HIV, we undertook, in a study of >1,000 C-clade-infected subjects, a comprehensive analysis of the epitopes presented by these 3 alleles and of the selection pressure imposed on HIV by each response. In contrast to previous studies, we show that each of these three HLA alleles is characterized both by unique CD8+T-cell specificities and by clear-cut differences in selection pressure imposed on the virus by those responses. These studies comprehensively define for the first time the CD8+T-cell responses and immune selection pressures for which these protective alleles are responsible. These findings are consistent with HLA class I alleles mediating effective immune control of HIV through the number of p24 Gag-specific CD8+T-cell responses generated that can drive significant selection pressure on the virus.
Cholesterol-Rich Microdomains as Docking Platforms for Respiratory Syncytial Virus in Normal Human Bronchial Epithelial Cells
Authors: San-Juan-Vergara Homero , Sampayo-Escobar Viviana , Reyes Niradiz , Cha Byeong , Pacheco-Lugo Lisandro , Wong Terianne , Peeples Mark E. , Collins Peter L. , Castaño Maria Eugenia , Mohapatra Shyam S.
Published: November 2011

Respiratory syncytial virus (RSV) is one of the major causes of respiratory infections in children, and it is the main pathogen causing bronchiolitis in infants. The binding and entry mechanism by which RSV infects respiratory epithelial cells has not yet been determined. In this study, the earliest stages of RSV infection in normal human bronchial epithelial cells were probed by tracking virions with fluorescent lipophilic dyes in their membranes. Virions colocalized with cholesterol-containing plasma membrane microdomains, identified by their ability to bind cholera toxin subunit B. Consistent with an important role for cholesterol in RSV infection, cholesterol depletion profoundly inhibited RSV infection, while cholesterol repletion reversed this inhibition. Merger of the outer leaflets of the viral envelope and the cell membrane appeared to be triggered at these sites. Using small-molecule inhibitors, RSV infection was found to be sensitive to Pak1 inhibition, suggesting the requirement of a subsequent step of cytoskeletal reorganization that could involve plasma membrane rearrangements or endocytosis. It appears that RSV entry depends on its ability to dock to cholesterol-rich microdomains (lipid rafts) in the plasma membrane where hemifusion events begin, assisted by a Pak1-dependent process.
Cloning and Analysis of Sooty Mangabey Alternative Coreceptors That Support Simian Immunodeficiency Virus SIVsmm Entry Independently of CCR5
Authors: Elliott Sarah T. C. , Riddick Nadeene E. , Francella Nicholas , Paiardini Mirko , Vanderford Thomas H. , Li Bing , Apetrei Cristian , Sodora Donald L. , Derdeyn Cynthia A. , Silvestri Guido , Collman Ronald G.
Published: November 2011

Natural host sooty mangabeys (SM) infected with simian immunodeficiency virus SIVsmm do not develop AIDS despite high viremia. SM and other natural hosts express very low levels of CCR5 on CD4
+
T cells, and we recently showed that SIVsmm infection and robust replication occur
in vivo
in SM genetically lacking CCR5, indicating the use of additional entry pathways. SIVsmm uses several alternative coreceptors of human origin
in vitro
, but which molecules of SM origin support entry is unknown. We cloned a panel of putative coreceptors from SM and tested their ability to mediate infection, in conjunction with smCD4, by pseudotypes carrying Envs from multiple SIVsmm subtypes. smCXCR6 supported efficient infection by all SIVsmm isolates with entry levels comparable to those for smCCR5, and smGPR15 enabled entry by all isolates at modest levels. smGPR1 and smAPJ supported low and variable entry, whereas smCCR2b, smCCR3, smCCR4, smCCR8, and smCXCR4 were not used by most isolates. In contrast, SIVsmm from rare infected SM with profound CD4
+
T cell loss, previously reported to have expanded use of human coreceptors, including CXCR4, used smCXCR4, smCXCR6, and smCCR5 efficiently and also exhibited robust entry through smCCR3, smCCR8, smGPR1, smGPR15, and smAPJ. Entry was similar with both known alleles of smCD4. These alternative coreceptors, particularly smCXCR6 and smGPR15, may support virus replication in SM that have restricted CCR5 expression as well as SM genetically lacking CCR5. Defining expression of these molecules on SM CD4
+
subsets may delineate distinct natural host target cell populations capable of supporting SIVsmm replication without CD4
+
T cell loss.
Lack of Association between HLA Class II Alleles and
In Vitro
Replication Capacities of Recombinant Viruses Encoding HIV-1 Subtype C Gag-Protease from Chronically Infected Individuals
Authors: Wright Jaclyn K. , Brumme Zabrina L. , Julg Boris , van der Stok Mary , Mncube Zenele , Gao Xiaojiang , Carlson Jonathan M. , Goulder Philip J. R. , Walker Bruce D. , Brockman Mark A. , Ndung'u Thumbi
Published: November 2011

It is unknown whether favorable HLA class II alleles may attenuate HIV-1 through selection pressure in a manner similar to that of protective HLA class I alleles. We investigated the relationship between HLA class II alleles and
in vitro
replication capacities of recombinant viruses encoding HIV-1 subtype C Gag-protease from chronically infected individuals. No associations were found between individual alleles and lower replication capacity, suggesting no significant HIV-1 attenuation by HLA class II-restricted Gag-specific CD4
+
T cell immune pressure.
Injury prevention and risk communication: a mental models approach
Authors: Austin Laurel C , Fischhoff Baruch
Published: November 2011

Individuals' decisions and behaviour can play a critical role in determining both the probability and severity of injury. Behavioural decision research studies peoples' decision-making processes in terms comparable to scientific models of optimal choices, providing a basis for focusing interventions on the most critical opportunities to reduce risks. That research often seeks to identify the ‘mental models’ that underlie individuals' interpretations of their circumstances and the outcomes of possible actions. In the context of injury prevention, a mental models approach would ask why people fail to see risks, do not make use of available protective interventions or misjudge the effectiveness of protective measures. If these misunderstandings can be reduced through context-appropriate risk communications, then their improved mental models may help people to engage more effectively in behaviours that they judge to be in their own best interest. If that proves impossible, then people may need specific instructions, not trusting to intuition or even paternalistic protection against situations that they cannot sufficiently control. The method entails working with domain specialists to elicit and create an expert model of the risk situation, interviewing lay people to elicit their comparable mental models, and developing and evaluating communication interventions designed to close the gaps between lay people and experts. This paper reviews the theory and method behind this research stream and uses examples to discuss how the approach can be used to develop scientifically validated context-sensitive injury risk communications.
Aggregates with lysozyme and ovalbumin show features of amyloid-like fibrils
Authors: Sugimoto Yasushi , Kamada Yoshiki , Tokunaga Yuhei , Shinohara Hiroshi , Matsumoto Mitsuharu , Kusakabe Takahiro , Ohkuri Takatoshi , Ueda Tadashi
Published: November 2011

The interaction of egg-white lysozyme with N-ovalbumin, the native form of egg-white ovalbumin with the denaturation temperature, Tm, of 78 °C, was investigated by the inhibition of lysozyme muramidase activity, differential scanning calorimetry, and circular dichroism assay as indicators. Signals for the interaction were the most prominent when the mixture of lysozyme and N-ovalbumin was co-heated at 72 °C, slightly lower than the Tmof N-ovalbumin. The interaction was also marked when unheated lysozyme was mixed with N-ovalbumin preheated at 72 °C. Moreover, the mixture rapidly formed fibrous precipitates, which were positive for thioflavin T fluorescent emission, a marker for the amyloid fibril formation. Also electron microscopic observation exhibited features of fibrils. The interaction potency of ovalbumin was ascribed to the tryptic fragment ILELPFASGT MSMLVLLPDE VSGLEQLESIINFEK (residues 229–263), derived from the 2B strands 2 and 3 of ovalbumin. From lysozyme, on the other hand, the chymotryptic peptide RNRCKGTDVQAW (residues 112–123), including cluster 6, and the chymotryptic/tryptic peptide GILQINSRW (residues 54–62), including cluster 3, were responsible for the interaction with N-ovalbumin. Interestingly, this nonamer peptide was found to have the ability to self-aggregate. To the authors knowledge, this may be the first report to document the possible involvement of dual proteins in the formation of amyloid-like fibrils.
Wnt-signaling mediates the anti-adipogenic action of lysophosphatidic acid through cross talking with the Rho/Rho associated kinase (ROCK) pathway
Authors: Li L. , Tam L. , Liu L. , Jin T. , Ng D.S.
Published: November 2011

Lysophosphatidic acid (LPA) is a bioactive phospholipid with a diverse range of biological activities including the modulation of adipogenesis. Treatment of 3T3-L1 cells and 3T3F44A cells with LPA inhibits adipogenesis and reduces expression of PPARγ through activation of RhoGTPase and its downstream Rho associated kinase (ROCK). The mechanism of suppression of PPARγ expression by Rho/ROCK is poorly understood. By treating the differentiating 3T3-L1 cells with various combinations of LPA and ROCK inhibitors, Y-27632 and fasudil, we observed that LPA treatment resulted in attenuation of adipogenesis and a significant reduction in PPARγ mRNA as early as 3 d post-induction. LPA treatment also resulted in significant but delayed upregulation of components of the canonical Wnt signaling, namely Wnt10b mRNA, β-catenin protein, and mRNA expression of β-catenin target genes, detectable at day 7, but not day 3. Treatment of the 3T3-L1 cells with ROCK inhibitors Y-27632 and fasudil revealed a tonic activation of β-catenin/target genes by ROCK. This study identified the existence of a novel cross talk between the Rho/ROCK pathway and the Wnt-signaling pathway. The LPA/Rho/ROCK pathway inhibits expression of PPARγ and adipogenesis in part through a delayed activation of the canonical Wnt-signaling pathway based on increased Wnt10b expression and β-catenin induction.
Hypoxia acts through multiple signaling pathways to induce metallothionein transactivation by the metal-responsive transcription factor-1 (MTF-1)
Authors: Dubé Annie , Harrisson Jean-François , Saint-Gelais Geneviève , Séguin Carl
Published: November 2011

Metal-responsive transcription factor-1 (MTF-1) is essential for the induction of genes encoding metallothionein by metals and hypoxia. Here, we studied the mechanism controlling the activation of MTF-1 by hypoxia. Hypoxia activation of Mt gene transcription is dependent on the presence of metal regulatory elements (MREs) in the promoter of Mt genes. We showed that MREa and MREd are the main elements controlling mouse Mt-1 gene induction by hypoxia. Transfection experiments in Mtf-1-null cells showed that MTF-1 is essential for induction by hypoxia. Chromatin immunoprecipitation analysis showed that MTF-1 DNA-binding activity was strongly enhanced in the presence of zinc but not by hypoxia. Notably, hypoxia inducible factor- (HIF) 1α was recruited to the Mt-1 promoter in response to hypoxia but not to zinc. MTF-1 activation was inhibited by PKC, JNK, and PI3K inhibitors and by the electron transport chain inhibitors rotenone and myxothiazol, but not by the antioxidant N-acetylcysteine. We showed that prolyl-hydroxylase inhibitors can activate MTF-1, but this activation requires the presence of HIF-1α. Finally, HIF-dependent transcription is enhanced in the presence of MTF-1 and induction of an MRE promoter is stimulated by HIF-1α, thus indicating cooperation between these 2 factors. However, coimmunoprecipitation experiments did not suggest direct interaction between MTF-1 and HIF-1α.
A WEIGHTED CHAOTIC BLOCK ENCRYPTION ALGORITHM USING MULTIPLE ONE-DIMENSIONAL CHAOTIC MAPS
Authors: WANG XING-YUAN , WANG XIAO-JUAN
Published: November 2011

This paper proposes a new block encryption algorithm. The chaotic trajectories are computed by weighting. Then the result is used to mask the plaintext. Multiple blocks of plaintext are encrypted at the same time and this decreases the chaotic iterations. So the encryption speed is improved to some extent. The proposed algorithm is flexible. When the number of weights is increased, the number of the encrypted plaintext block at the same time is increased and the encryption speed is improved. The simulation result shows that the proposed algorithm has fast encryption speed and fine security.
LAG SYNCHRONIZATION OF THE FRACTIONAL-ORDER SYSTEM VIA NONLINEAR OBSERVER
Authors: ZHU HAO , HE ZHONGSHI , ZHOU SHANGBO
Published: November 2011

In this paper, based on the idea of nonlinear observer, lag synchronization of chaotic fractional system with commensurate and incommensurate order is studied by the stability theorem of linear fractional-order systems. The theoretical analysis of fractional-order systems in this paper is a systematic method. This technique is applied to achieve the lag synchronization of fractional-order Rössler's system, verified by numerical simulation.
KNOTTED PERIODIC ORBITS AND CHAOTIC BEHAVIOR OF A CLASS OF THREE-DIMENSIONAL FLOWS
Authors: LI JIBIN , CHEN FENGJUAN
Published: November 2011

This paper considers a class of three-dimensional systems constructed by rotating some planar symmetric polynomial vector fields. It shows that this class of systems has infinitely many distinct types of knotted periodic orbits, which lie on a family of invariant torus. For two three-dimensional systems, exact explicit parametric representations of the knotted periodic orbits are given. For their perturbed systems, the chaotic behavior is discussed by using two different methods.
Constraints on the seismic properties of the middle and lower continental crust
Authors: Lloyd G. E. , Butler R. W. H. , Casey M. , Tatham D. J. , Mainprice D.
Published: November 2011

For the past two decades geodetic measurements have quantified surface displacement fields for the continents, illustrating a general complexity. However, the linkage of geodetically defined displacements in the continents to mantle flow and plate tectonics demands understanding of ductile deformations in the middle and lower continental crust. Advances in seismic anisotropy studies are beginning to allow such work, especially in the Himalaya and Tibet, using passive seismological experiments (e.g. teleseismic receiver functions and records from local earthquakes). Although there is general agreement that measured seismic anisotropy in the middle and lower crust reflects bulk mineral alignment (i.e. crystallographic preferred orientation, CPO), there is a need to calibrate the seismic response to deformation structures and their kinematics. Here, we take on this challenge by deducing the seismic properties of typical mid- and lower-crustal rocks that have experienced ductile deformation through quantitative measures of CPO in samples from appropriate outcrops. The effective database of CPO and hence seismic properties can be expanded by a modelling approach that utilizes ‘rock recipes’ derived from the as-measured individual mineral CPOs combined in varying modal proportions. In addition, different deformation fabrics may be diagnostic of specific deformation kinematics that can serve to constrain interpretations of seismic anisotropy data from the continental crust. Thus, the use of ‘fabric recipes’ based on subsets of individual rock fabric CPO allows the effect of different fabrics (e.g. foliations) to be investigated and interpreted from their seismic response. A key issue is the possible discrimination between continental crustal deformation models with strongly localized simple-shear (ductile fault) fabrics from more distributed (‘pure-shear’) crustal flow. The results of our combined rock and fabric-recipe modelling suggest that the seismic properties of the middle and lower crust depend on deformation state and orientation as well as composition, while reliable interpretation of seismic survey data should incorporate as many seismic properties as possible.
Alice on both sides of the looking glass
Authors: Jacquemin Christian , Ajaj Rami , Planes Bertrand
Published: November 2011

The "Virtuality Continuum" describes the possible variety of mixed reality setups between virtual environments and the real world depending on the ratio of digital and physical elements. We study here another type of continuity that concerns the perceptual (mainly visual) coherence between the real and virtual worlds. This notion is of particular importance for the use of new media in the performing arts and installations, but is also known to be a key issue in the sense of immersion. By examining studies on film editing and on the design of Mixed Reality applications, three principles are defined for the sake of perceptual continuity and compatibility: point-of-view, space and time coherence, and illumination. Examples of art installations are analyzed according to these principles and illustrated through this model. Since it seems to us that illumination has been underestimated in the studies on perceptual coherence, the continuity of illumination in a Mixed Reality performance is described in more details at the level of real and virtual shadowing. From the implementation of these artworks, practical simplifications and a software architecture are proposed for the design of interactive Mixed Reality applications that follow the three principles of perceptual continuity. Future directions for a better integration of the real and virtual worlds are proposed together with their technological requirements.
Experiences with rapid mobile game development using unity engine
Authors: de Macedo Daniel V. , Formico Rodrigues Maria Andréia
Published: November 2011

In this work, we describe our experiences with FunCopter, a casual game we have designed and implemented using Unity engine, suitable for portable devices. We emphasize some general principles, particularly with respect to rapid game development and constrained graphics. In addition to that, we present the main activities realized in each software engineering phase and the lessons we learned during its development. These descriptions include details from the initial concept to the fully realized, playable game. This work will share general but important experiences with Unity, particularly interesting for game developers in beginner's level.
Investigation of the antecedents and consequences of gamer satisfaction
Authors: Theng Yin-Leng , Wanzhen Liaw , Zhiqiang Li , Robert Chai , Pallavi Rao
Published: November 2011

New game technologies are changing the way people learn, play, socialize and participate in civic life. However, designing good games is challenging and expensive. While technologies have been improving swiftly, game design guidelines have evolved slowly. This article proposes a theoretical approach to study the key factors leading to successful online games. We first developed a theoretical model,
P
layability for
A
cceptance and
A
doption
M
odel (
PAAM
) for conciseness, linking the antecedents into the key factors using information acquired from an extended literature review. We then undertook a survey of 201 online gamers to investigate key factors affecting players' acceptance of online games. Through structural equation modeling, our findings showed that the “perceived benefits” construct is dependent on whether online games met gamers' goals for entertainment or leisure activities, in-game experiences, and out-game needs, while the “perceived ease of use” construct is determined by game design and facilitating conditions. We believe our theoretical model and results are useful to designers and developers of software companies when creating online games that will satisfy gamers' goals, in-game experiences, and out-game needs for playability.
Player experience and technical performance prospects for distributed 3D gaming in private and public settings
Authors: Jurgelionis Audrius , Nap Henk Herman , Gajadhar Brian J. , Bellotti Francesco , Wang A. I. , Berta Riccardo
Published: November 2011

Distributed gaming enables access to interactive media from devices based on different platforms. It facilitates users to enjoy video games in various environments without the need for using a single device or operating system. Understanding the potential and limitations of such gaming-on-demand systems is key for their adoption and further growth in public places. This paper presents an in-depth, quantitative study performed with the Games@Large (GaL) distributed-gaming system and its potential users at an Internet café in Genoa, Italy. The approach of the study was multilevel, covering the player experience and user acceptance aspects as well as technical performance peculiarities. Results show that the GaL system has a high potential at Internet cafes, in particular when playing a casual genre game. Furthermore, results provide recommendations for deploying such systems in terms of social setting and technical aspects. The methodology and findings of the GaL system tests can be applied to similar game streaming systems and used as input for theories on social digital game play.
Fast low-memory seamless photo blending on massive point clouds using a streaming framework
Authors: Pintus Ruggero , Gobbetti Enrico , Callieri Marco
Published: November 2011

We present an efficient scalable streaming technique for mapping highly detailed color information on extremely dense point clouds. Our method does not require meshing or extensive processing of the input model, works on a coarsely spatially reordered point stream, and can adaptively refine point cloud geometry on the basis of image content. Seamless multiband image blending is obtained by using GPU-accelerated screen-space operators, which solve point set visibility, compute a per-pixel view-dependent weight, and ensure a smooth weighting function over each input image. The proposed approach works independently on each image in a memory-coherent manner, and can be easily extended to include further image-quality estimators. The effectiveness of the method is demonstrated on a series of massive real-world point datasets.