bluuebunny/crossref_metadata_2025_split huggingface dataset:
Murine Leukemia Virus R Peptide Inhibits Influenza Virus Hemagglutinin-Induced Membrane Fusion
Authors: Li Min , Li Zhu-Nan , Yao Qizhi , Yang Chinglai , Steinhauer David A. , Compans Richard W. 
Published: May 2006

ABSTRACT
The cytoplasmic tail of the murine leukemia virus (MuLV) envelope (Env) protein is known to play an important role in regulating viral fusion activity. Upon removal of the C-terminal 16 amino acids, designated as the R peptide, the fusion activity of the Env protein is activated. To extend our understanding of the inhibitory effect of the R peptide and investigate the specificity of inhibition, we constructed chimeric influenza virus-MuLV hemagglutinin (HA) genes. The influenza virus HA protein is the best-studied membrane fusion model, and we investigated the fusion activities of the chimeric HA proteins. We compared constructs in which the coding sequence for the cytoplasmic tail of the influenza virus HA protein was replaced by that of the wild-type or mutant MuLV Env protein or in which the cytoplasmic tail sequence of the MuLV Env protein was added to the HA cytoplasmic domain. Enzyme-linked immunosorbent assays and Western blot analysis showed that all chimeric HA proteins were effectively expressed on the cell surface and cleaved by trypsin. In BHK21 cells, the wild-type HA protein had a significant ability after trypsin cleavage to induce syncytium formation at pH 5.1; however, neither the chimeric HA protein with the full-length cytoplasmic tail of MuLV Env nor the full-length HA protein followed by the R peptide showed any syncytium formation. When the R peptide was truncated or mutated, the fusion activity was partially recovered in the chimeric HA proteins. A low-pH conformational-change assay showed that similar conformational changes occurred for the wild-type and chimeric HA proteins. All chimeric HA proteins were capable of promoting hemifusion and small fusion pore formation, as shown by a dye redistribution assay. These results indicate that the R peptide of the MuLV Env protein has a sequence-dependent inhibitory effect on influenza virus HA protein-induced membrane fusion and that the inhibitory effect occurs at a late stage in fusion pore enlargement.
Human Cytomegalovirus (HCMV) UL82 Gene Product (pp71) Relieves hDaxx-Mediated Repression of HCMV Replication
Authors: Cantrell Stacy R. , Bresnahan Wade A. 
Published: May 2006

ABSTRACT
This study examines the role of the cellular protein hDaxx in controlling human cytomegalovirus (HCMV) immediate-early (IE) gene expression and viral replication. Using permissive cell lines that either overexpress hDaxx or are depleted of hDaxx expression by the use of short hairpin RNA, we demonstrate that hDaxx functions as a repressor of HCMV IE gene expression and replication. In addition, we demonstrate that the impaired growth phenotype associated with the UL82 (pp71) deletion mutant is abolished when hDaxx knockdown cells are infected, suggesting that pp71 functions to relieve hDaxx-mediated repression during HCMV infection.
Biochemical Activities of Highly Purified, Catalytically Active Human APOBEC3G: Correlation with Antiviral Effect
Authors: Iwatani Yasumasa , Takeuchi Hiroaki , Strebel Klaus , Levin Judith G. 
Published: May 2006

ABSTRACT
APOBEC3G (APO3G), a cytidine deaminase with two zinc finger domains, inhibits
human immunodeficiency virus type 1 replication in the absence of Vif.
Here, we provide a comprehensive molecular analysis of the deaminase
and nucleic acid binding activities of human APO3G using a pure system
containing only one protein component, i.e., highly purified,
catalytically active enzyme expressed in a baculovirus system. We
demonstrate that APO3G deaminates cytosines in single-stranded DNA
(ssDNA) only, whereas it binds efficiently to ssDNA and ssRNA, about
half as well to a DNA/RNA hybrid, and poorly to double-stranded DNA and
RNA. In addition, the base specificities for deamination and binding of
ssDNA are not correlated. The minimum length required for detection of
APO3G binding to an ssDNA oligonucleotide in an electrophoretic
mobility shift assay is 16 nucleotides. Interestingly, if nucleocapsid
protein and APO3G are present in the same reaction, we find that they
do not interfere with each other's binding to RNA and a complex
containing the RNA and both proteins is formed. Finally, we also
identify the functional activities of each zinc finger domain. Thus,
although both zinc finger domains have the ability to bind nucleic
acids, the first zinc finger contributes more to binding and APO3G
encapsidation into virions than finger two. In contrast, deamination is
associated exclusively with the second zinc finger. Moreover, zinc
finger two is more important than finger one for the antiviral effect,
demonstrating a correlation between deaminase and antiviral
activities.
Peptide Aptamers That Bind to a Geminivirus Replication Protein Interfere with Viral Replication in Plant Cells
Authors: Lopez-Ochoa Luisa , Ramirez-Prado Jorge , Hanley-Bowdoin Linda 
Published: May 2006

ABSTRACTThe AL1 protein of tomato golden mosaic virus (TGMV), a member of the geminivirus family, is essential for viral replication in plants. Its N terminus contains three conserved motifs that mediate origin recognition and DNA cleavage during the initiation of rolling-circle replication. We used the N-terminal domain of TGMV AL1 as bait in a yeast two-hybrid screen of a random peptide aptamer library constrained in the active site of the thioredoxin A (TrxA) gene. The screen selected 88 TrxA peptides that also bind to the full-length TGMV AL1 protein. Plant expression cassettes corresponding to the TrxA peptides and a TGMV A replicon encoding AL1 were cotransfected into tobacco protoplasts, and viral DNA replication was monitored by semiquantitative PCR. In these assays, 31 TrxA peptides negatively impacted TGMV DNA accumulation, reducing viral DNA levels to 13 to 64% of those of the wild type. All of the interfering aptamers also bound to the AL1 protein of cabbage leaf curl virus. A comparison of the 20-mer peptides revealed that their sequences are not random. The alignments detected seven potential binding motifs, five of which are more highly represented among the interfering peptides. One motif was present in 18 peptides, suggesting that these peptides interact with a hot spot in the AL1 N terminus. The peptide aptamers characterized in these studies represent new tools for studying AL1 function and can serve as the basis for the development of crops with broad-based resistance to single-stranded DNA viruses.
Activation of Vav by the Gammaherpesvirus M2 Protein Contributes to the Establishment of Viral Latency in B Lymphocytes
Authors: Rodrigues Lénia , Pires de Miranda Marta , Caloca María J. , Bustelo Xosé R. , Simas J. Pedro 
Published: May 2006

ABSTRACTGammaherpesviruses subvert eukaryotic signaling pathways to favor latent infections in their cellular reservoirs. To this end, they express proteins that regulate or replace functionally specific signaling proteins of eukaryotic cells. Here we describe a new type of such viral-host interaction that is established through M2, a protein encoded by murine gammaherpesvirus 68. M2 associates with Vav proteins, a family of phosphorylation-dependent Rho/Rac exchange factors that play critical roles in lymphocyte signaling. M2 expression leads to Vav1 hyperphosphorylation and to the subsequent stimulation of its exchange activity towards Rac1, a process mediated by the formation of a trimolecular complex with Src kinases. This heteromolecular complex is coordinated by proline-rich and Src family-dependent phosphorylated regions of M2. Infection of Vav-deficient mice with gammaherpesvirus 68 results in increased long-term levels of latency in germinal center B lymphocytes, corroborating the importance of the M2/Vav cross talk in the process of viral latency. These results reveal a novel strategy used by the murine gammaherpesvirus family to subvert the lymphocyte signaling machinery to its own benefit.
Bovine Herpesvirus 1 UL49.5 Protein Inhibits the Transporter Associated with Antigen Processing despite Complex Formation with Glycoprotein M
Authors: Lipińska Andrea D. , Koppers-Lalic Danijela , Rychłowski Michał , Admiraal Pieter , Rijsewijk Frans A. M. , Bieńkowska-Szewczyk Krystyna , Wiertz Emmanuel J. H. J. 
Published: May 2006

ABSTRACT

Bovine herpesvirus 1 (BHV-1) interferes with peptide translocation by the transporter associated with antigen processing (TAP). Recently, the UL49.5 gene product of BHV-1 was identified as the protein responsible for the observed inhibition of TAP. In BHV-1-infected cells and virions, the UL49.5 protein forms a complex with glycoprotein M (gM). Hence, it was investigated whether UL49.5 can combine the interactions with gM and the TAP complex. In cell lines constitutively expressing both UL49.5 and gM, UL49.5 appears to be required for functional processing of gM. Immunofluorescence-confocal laser scanning microscopy demonstrated that both proteins are interdependent for their redistribution from the endoplasmic reticulum to the
trans
-Golgi network. Remarkably, expression of cloned gM results in the abrogation of the UL49.5-mediated inhibition of TAP and prevents the degradation of the transporter. However, in BHV-1-infected cells, differences in UL49.5 and gM expression kinetics were seen to create a window of opportunity at the early stages of infection, during which time the UL49.5 protein can act on TAP without gM interference. Moreover, in later periods, non-gM-associated UL49.5 can be detected in addition to the UL49.5/gM complex. Thus, it has been deduced that different functions of UL49.5, editing of gM processing and inhibition of TAP, can be combined during BHV-1 infection.
Sindbis Virus Nonstructural Protein nsP2 Is Cytotoxic and Inhibits Cellular Transcription
Authors: Garmashova Natalia , Gorchakov Rodion , Frolova Elena , Frolov Ilya 
Published: May 2006

ABSTRACT
Replication of alphaviruses in vertebrate cells strongly affects cell physiology and ultimately leads to development of a cytopathic effect (CPE) and cell death. Sindbis virus (SIN) replication causes major changes in cellular macromolecular synthesis, in which the strong downregulation of transcription of cellular mRNAs and rRNAs plays a critical role. SIN nonstructural protein nsP2 was previously proposed as one of the main regulators of virus-host cell interactions, because point mutations in the carboxy-terminal part of nsP2 could make SIN and other alphaviruses and replicons less cytopathic and capable of persisting in some vertebrate cell lines. These mutants were incapable of inhibiting transcription and downregulating a viral stress-induced cell response. In the present work, we demonstrate that (i) SIN nsP2 is critically involved in CPE development, not only during the replication of SIN-specific RNAs, but also when this protein is expressed alone from different expression cassettes; (ii) the cytotoxic effect of SIN nsP2 appears to be at least partially determined by its ability to cause transcriptional shutoff; (iii) these functions of SIN nsP2 are determined by the integrity of the carboxy-terminal peptide of this protein located outside its helicase and protease domains, rather than by its protease activity; and (iv) the cytotoxic activity of SIN nsP2 depends on the presence of this protein in a free form, and alterations in P123 processing abolish the ability of nsP2 to cause CPE.
3-
O
-(3′,3′-Dimethysuccinyl) Betulinic Acid Inhibits Maturation of the Human Immunodeficiency Virus Type 1 Gag Precursor Assembled In Vitro
Authors: Sakalian Michael , McMurtrey Curtis P. , Deeg Frederick J. , Maloy Christopher W. , Li Feng , Wild Carl T. , Salzwedel Karl 
Published: May 2006

ABSTRACT

3-
O
-(3′,3′-Dimethysuccinyl) betulinic acid (PA-457) has been shown to potently inhibit human immunodeficiency virus (HIV) replication in culture. In contrast to inhibitors that act upon the viral proteinase, PA-457 appears to block only the final maturational cleavage of p25CA-p2 to p24CA. However, attempts to replicate this effect in vitro using recombinant Gag have failed, leading to the hypothesis that activity is dependent upon the assembly state of Gag. Using a synthesis/assembly system for chimeric HIV type 1 Gag proteins, we have replicated the activity of PA-457 in vitro. The processing of assembled chimeric Gag can be inhibited by the addition of drug with only the final cleavage of p25CA-p2 to p24CA blocked. Consistent with our hypothesis and with previous findings, inhibition appears specific to Gag assembled into an immature capsid-like structure, since synthetic Gag that remains unassembled is properly processed in the presence of the compound. To further analyze the authenticity of the assay, PA-457 was tested in parallel with its inactive parental compound, betulinic acid. Betulinic acid had no effect upon p25 processing in this system. Analysis of a PA-457-resistant mutant, A1V, in this system pointed to more rapid cleavage as a possible mechanism for resistance. However, characterization of additional mutations at the cleavage site and in p2 suggests that resistance does not strictly correlate with the rate of cleavage. With the establishment of an in vitro assay for the detection of PA-457 activity, a more detailed characterization of its mechanism of action will be possible.
Primary care confidentiality for Spanish adolescents: fact or fiction?
Authors: Pérez-Cárceles M D , Pereñiguez J E , Osuna E , Pérez-Flores D , Luna A 
Published: May 2006

Background:By providing healthcare to adolescents, a major opportunity is created to help them cope with the challenges in their lives, develop healthy behaviour and become responsible healthcare consumers. Confidentiality is a major issue in adolescent healthcare, and its perceived absence may be the main barrier to an adolescent seeking medical care. Little is known, however, about confidentiality for adolescents in primary care practices in Spain.Objective:To ascertain the attitudes of Spanish family doctors towards the right of adolescents to confidentiality in different healthcare situations and in the prescription of treatment.Method:A descriptive postal questionnaire was self-administered by family doctors.Results:Parents of patients under 18 years are always informed by 18.5% of family doctors, whereas parents of those under 16 years are informed by 38.8% of doctors. The patients are warned of this likelihood by 79.3% of doctors. The proportion of doctors supporting confidentiality for adolescents increases with the age and maturity of the patients, whereas workload and previous training has a negative effect.Conclusions:Spanish laws on adolescent healthcare are not reflected by the paternalistic attitude that Spanish primary care doctors have towards their adolescent patients. Doctors need to be provided with up-to-date and clinically relevant explanations on contemporary legal positions. In primary care, more attention should be paid to adolescents’ rights to information, privacy and confidentiality. Doctors should be more aware of the need to encourage communication between teenagers and their parents, while also safeguarding their patients’ rights to confidential care.
Paradoxical increase in cigarette smuggling after the market opening in Taiwan
Authors: Wen C P , Peterson R A , Cheng T Y D , Tsai S P , Eriksen M P , Chen T 
Published: May 2006

Objectives:To assess the magnitude of cigarette smuggling after the market opened in Taiwan.Methods:Review of tobacco industry documents for references to smuggling activities related to Taiwan and government statistics on seizure of smuggled cigarettes.Results:The market opening in 1987 led to an increase in smuggling. Contraband cigarettes became as available as legal ones, with only a small fraction (8%) being seized. Being specifically excluded from the market-opening, Japan entered the Taiwan market by setting up a Swiss plant as a legal cover for smuggling 10–20 times its legal quota of exports to Taiwan. Smuggling in Taiwan contributed to increased consumption of foreign brands, particularly by the young. Taiwan, not a member of the World Health Organization, was excluded from the East Asian 16-member “Project Crocodile”, a regional anti-smuggling collaborative effort to implement the Framework Convention on Tobacco Control.Conclusions:Taiwan showed a sharp increase in smuggling after market liberalisation. Being excluded from the international community, Taiwan faces an uphill battle to fight smuggling alone. If Taiwan remained as its weakest link, global efforts to reduce tobacco use will be undermined, particularly for countries in the East Asian region.
The Philip Morris External Research Program: results from the first round of projects
Authors: Hirschhorn N , Bialous S Aguinaga , Shatenstein S 
Published: May 2006

Background:Philip Morris (PM) launched the Philip Morris External Research Program (PMERP) in 2000, two years after the company agreed to the dissolution of two industry-wide, external research programmes: the Council for Tobacco Research (CTR) and the Center for Indoor Air Research (CIAR). Our previous analysis of PMERP’s Request for Applications noted that PMERP’s structure, while ostensibly concerned with new product development, was remarkably similar to that of CIAR. We also found the majority of designated peer-reviewers had previous ties to the tobacco industry and the research solicitation seemed to invite mitigating evidence concerning cigarettes and constituent risks. We concluded that a prime reason for PMERP’s existence was to garner scientific credibility for PM.Objective:To examine the grants awarded in the first round of PMERP and subsequent peer-reviewed publications.Methods:Searches of industry documents available on the internet using PMERP and its variations as initial keywords; searches on Medline for publications from PMERP grantees.Results:Of 153 applications, 61 proposals were funded, 36 of which generated 78 scientific publications. Of these, 65% deal specifically with the tobacco plant or constituents. Over half the researchers listed as PMERP participants had previously received or applied for tobacco funding. One internal document indicated PMERP’s objectives included gaining “credibility” and “goodwill”, and finding “young scientists”. In addition, PM has launched its own and more extensive internal product design research programme.Conclusion:PMERP appears to exist less as a conduit for critical scientific inquiry than to fit into a corporate strategy intended to burnish PM’s public image.
Risk factors for tobacco dependence in adolescent smokers
Authors: Karp I , O’Loughlin J , Hanley J , Tyndale R F , Paradis G 
Published: May 2006

Objective:To study the incidence of conversion to tobacco dependence (TD) and the prevalence of the TD state in relation to several potential determinants in a sample of adolescent smokers.Methods:Questionnaires were administered every 3–4 months to document TD symptoms, amount of cigarette consumption, and depression symptoms in a prospective cohort of 1293 grade 7 students in a convenience sample of 10 schools.Results:Over 54 months of follow-up, 113 of 344 novice smokers converted to TD. The referent series for the analysis of incidence comprised 823 person-surveys. The prevalence series included 1673 person-surveys, contributed by 429 smokers. Conversion to TD and TD status were associated with the intensity of recent (that is, past 3-month) cigarette consumption (adjusted incidence rate ratio (aIRR) 1.63 (95% confidence interval (CI) 1.36 to 1.97) and adjusted prevalence odds ratio (aPOR) 1.35 (95% CI 1.23 to 2.48) per 100 cigarettes per month), slowest CYP2A6 activity (aIRR 4.19 (95% CI 1.38 to 12.76) and aPOR 2.30 (95% CI 1.29 to 4.09)), depression score (aIRR 1.61 (95% CI 1.17 to 2.21) and aPOR 1.47 (95% CI 1.22, 1.75) per 1-unit change). Additional determinants included, for conversion to TD, time since onset of cigarette use (aIRR 0.76 (95% CI 0.58 to 1.00) per year) and, for the TD state, positive TD status six months ago (aPOR 3.53 (95% CI 2.41 to 5.19)).Conclusions:TD risk in adolescents is associated with intensity of recent cigarette consumption, while the role of more distant cigarette consumption appears small; subjects with slow nicotine metabolism and those with more depression symptoms are at increased risk of becoming tobacco dependent. The risk of being tobacco dependent is considerably higher in subjects who had previously developed the TD state.
Why are urban Indian 6th graders using more tobacco than 8th graders? Findings from Project MYTRI
Authors: Stigler M H , Perry C L , Arora M , Reddy K S 
Published: May 2006

Objective:To investigate why urban Indian 6th graders may be using more tobacco than urban Indian 8th graders.Design:Cross-sectional survey of students conducted in the summer of 2004, as the baseline evaluation tool for a group-randomised tobacco prevention intervention trial (Project MYTRI). Mixed-effects regression models were used to (1) examine the relationship between 15 psychosocial risk factors and current use of any tobacco, by grade; and (2) examine differences in psychosocial risk factors, by grade.Setting:Thirty-two private (high socioeconomic status (SES)) and government (low-mid SES) schools in two large cities in India (Delhi and Chennai).Subjects:Students in the 6th and 8th grade in these schools (n  =  11642). Among these, 50.6% resided in Delhi (vChennai), 61.4% attended a government school (va private school), 52.9% were enrolled in 6th grade (v8th), and 54.9% were male (vfemale).Main outcome measure:Current (past 30 day) use of any tobacco, including chewing tobacco (for example, gutkha), bidis, or cigarettes.Result:Almost all psychosocial factors were significantly related to tobacco use, for students in both grades. Some of the strongest correlates included social susceptibility to and social norms about use. Exposure to tobacco advertising was a strong correlate of tobacco use for 6th graders, but not for 8th graders. Sixth graders scored lower than 8th graders on almost all factors, indicating higher risk.Conclusions:The “risk profile” of 6th graders suggests they would be vulnerable to use and to begin using tobacco, as well as to outside influences that may encourage use.
China at the crossroads: the economics of tobacco and health
Authors: Hu T-W , Mao Z , Ong M , Tong E , Tao M , Jiang H , Hammond K , Smith K R , de Beyer J , Yurekli A 
Published: May 2006

Objective:To analyse economic aspects of tobacco control policy issues in China.Methods:Published and collected survey data were used to analyse economic consequences of smoking. Economic analysis was used to address the role of tobacco farmers and the cigarette industry in the Chinese economy.Results:In the agricultural sector, tobacco has the lowest economic rate of return of all cash crops. At the same time, the tobacco industry’s tax contribution to the central government has been declining.Conclusion:Economic gains become less important as the negative health impact of smoking on the population garners more awareness. China stands at a crossroads to implement the economic promises of the World Health Organization’s Framework Convention on Tobacco Control and promote the health of its population.