bluuebunny/crossref_metadata_2025 huggingface dataset:
A theoretical study of resonance Raman scattering from molecules. II. Temperature effect
Authors: Fujimura Y. , Lin S. H.
Published: February 2003

The temperature effect on the resonance Raman scattering from molecules is investigated. Considering a total system consisting of a molecular system, a heat bath, and the weak radiation field, a general expression for the relaxation processes is derived utilizing the Liouville operator technique for the time evolution of the density matrix of the total system. By using the perturbation method with respect to the radiation and matter up to second order, rate constants for zero photon (radiationless processes), one-photon and two-photon processes are derived after taking the long time limit in the Markoff approximation. Assuming a weak interaction between the molecular system and heat bath, a temperature-dependent resonance Raman scattering cross section is formulated in the adiabatic basis set for the molecular systems. In the displaced harmonic oscillator model, we obtain an analytical expression for the temperature-dependent Raman scattering cross section for the multimode case, which is suitable for both weak coupling and strong coupling cases. Analytical expressions for the Stokes and anti-Stokes bands of the jth order vibrational transition in the one oscillator model can easily be obtained from the general expression for the resonance Raman scattering cross section derived. An approximate Stokes to anti-Stokes ratio is given up to the second order of the dimensionless displacement Δ. The resonance Raman scattering cross section and the excitation energy profiles are numerically calculated as a function of physical constant such as temperature, molecular vibrational frequency and Δ. It is shown that the excitation profiles of the anti-Stokes band of the jth order vibrational transition have the similar envelope of the corresponding Stokes band shifted by jh/ω. The inverse Raman effect which is closely related to the ordinary Raman effect is also discussed.
Requests for information from a film archive: a case study of multimedia retrieval
Authors: Hertzum Morten
Published: February 2003

Multimedia retrieval is a complex and to some extent still unexplored area. Based on a full year of e‐mail requests addressed to a large film archive this study analyses what types of information needs real users have and how these needs are expressed. The findings include that the requesters make use of a broad range of need attributes in specifying their information needs. These attributes relate to the production, content, subject, context and screening of films. However, a few attributes – especially title, production year and director – account for the majority of the attribute instances. Further, as much as 43 per cent of the requests contain no information about the context that gives rise to the request. The current indexing of the archived material is restricted to production‐related attributes, and access to the material is, thus, frequently dependent on the archivists’ extensive knowledge of the archived material and films in general.
Can Google's PageRank be used to find the most important academic Web pages?
Authors: Thelwall Mike
Published: February 2003

Google's PageRank is an influential algorithm that uses a model of Web use that is dominated by its link structure in order to rank pages by their estimated value to the Web community. This paper reports on the outcome of applying the algorithm to the Web sites of three national university systems in order to test whether it is capable of identifying the most important Web pages. The results are also compared with simple inlink counts. It was discovered that the highest inlinked pages do not always have the highest PageRank, indicating that the two metrics are genuinely different, even for the top pages. More significantly, however, internal links dominated external links for the high ranks in either method and superficial reasons accounted for high scores in both cases. It is concluded that PageRank is not useful for identifying the top pages in a site and that it must be combined with a powerful text matching techniques in order to get the quality of information retrieval results provided by Google.
International protection of trade secrets when using the Internet
Authors: Apke Thomas M.
Published: February 2003

Protection and enforcement of trade secrets outside the USA have been minimal and undeveloped and of particular concern when using the Internet. Substantive and procedural laws vary from country to country. In recent years there has been a move toward harmonization under the North American Free Trade Association (NAFTA) and the Trade Related Aspects of Intellectual Property Rights (TRIPS) agreement under the General Agreement on Tariffs and Trade (GATT) 1994. However, the provisions of TRIPS allow for varying periods for member countries to come into compliance. In the meantime international protection of trade secrets is uncertain, thus necessitating the development and implementation of strategies for preserving trade secrets in the international business environment. This paper discusses those strategies, beginning with defining and identifying a company’s trade secrets and the formulation of various policy measures to be taken to protect trade secrets, with emphasis on the risks inherent in the loss of trade secrets when using the Internet and how to eliminate or reduce that risk.
Nothing new under the sun: transformational leadership from a historical perspective
Authors: Humphreys John H. , Einstein Walter O.
Published: February 2003

Transformational leadership theory is a relatively recent entrant into the realm of management thought. In fact, the majority of this literature has been published in the past 15 years. That being said, the ideas that are central to transformational leadership are not necessarily new. Many of these constructs can be found in the writings of earlier management theorists. The literature indicates that transformational leadership can positively impact on organizational outcomes and employee satisfaction. Without an understanding of its historical roots, however, transformational leadership risks becoming nothing more than the latest “buzzword” for enhancing organizational performance. To fully understand and appreciate the paradigm, one must trace the development of the transformational factors from a historical perspective.
Assessing partnership: the prospects for, and challenges of, modernisation
Authors: Martinez Lucio Miguel , Stuart Mark
Published: February 2003

This paper has a dual role. First, it provides an overview of partnership, with particular reference to the present Labour Government and the shaping of its relations with the institutions of capital and business representation. Second, it provides an introduction to the special issue on “‘Assessing partnership: the prospects for, and challenges of, modernisation” and briefly outlines the papers included in it.
“Working together – involving staff”
Authors: Munro Anne
Published: February 2003

Contributes to debates about employee involvement and social partnership by exploring the ways in which individualist and collectivist aspects interrelate in a single initiative in the National Health Service. Identifies a particular form of employee involvement in which partnership is integral. Draws on a case study of one NHS Trust over a period of 18 months, using individual and group interviews with senior and line managers, union officials, shop stewards and staff. Argues that tension between collectivism and individualism becomes more acute lower down the organisation where line managers are responsible for implementing change. Highlights how understanding of involvement and partnership change over time and how a climate that is more amenable to union organisation can be created.
Partnership and process in the maritime construction industry
Authors: McBride Jo , Stirling John
Published: February 2003

The authors provide a case study of a partnership agreement in the Tyneside maritime construction industry. They focus on the role of trade unions and the complex tensions that emerge between regional and local officials and workplace representatives. They argue that agreements can only be understood within the context of existing employee relations structures. Their conclusion suggests that the agreement had little impact on a “branch plant” of a national company and that it was often received with hostility and little commitment. As a consequence the partnership became a symbolic agreement with potential significance for external customers but no role in shaping workplace employee relations.
Assessing the principles of partnership
Authors: Martinez Lucio Miguel , Stuart Mark
Published: February 2003

The article examines the attitudes and experiences of senior workplace trade union representatives, from the Manufacturing, Science and Finance Union, against the TUC’s six principles of partnership. The findings suggest some acceptance of the ideological aspects of partnership, such as the need to move away from adversarial cultures and understand the impact of market imperatives and pressures on the firm. The results reveal little support, however, for improvements in job security, transparency and involvement and the quality of working life (the TUC’s so‐called “acid test” of partnership). Against a backdrop of job insecurity and widespread work intensification, the article argues that the material and organisational basis to partnership appears to be undermining various attitudinal changes within the thinking of trade union representatives regarding their roles and relations at work.
Partnership, ownership and control
Authors: Deakin Simon , Hobbs Richard , Konzelmann Suzanne , Wilkinson Frank
Published: February 2003

Prevailing patterns of dispersed share ownership and rules of corporate governance for UK listed companies appear to constrain the ability of managers to make credible, long‐term commitments to employees of the kind needed to foster effective labour‐management partnerships. We present case study evidence which suggests that such partnerships can nevertheless emerge where product market conditions and the regulatory environment favour a stakeholder orientation. Proactive and mature partnerships may also be sustained where the board takes a strategic approach to mediating between the claims of different stakeholder groups, institutional investors are prepared to take a long‐term view of their holdings, and strong and independent trade unions are in a position to facilitate organisational change.
CPFR: an emerging supply chain tool
Authors: Fliedner Gene
Published: February 2003

This paper examines collaborative planning, forecasting, and replenishment (CPFR), a Web‐based tool to coordinate the various supply chain management activities including production and purchase planning, demand forecasting, and inventory replenishment between supply chain trading partners. This paper identifies what CPFR is, explains the CPFR process, cites benefits that have been achieved, identifies obstacles to implementation, and discusses the future of CPFR.
Modeling and implementation of supplier selection procedures for e‐commerce initiatives
Authors: Davidrajuh Reggie
Published: February 2003

The main work in this paper covers a methodology, tools and implementation techniques for automation of supplier selection procedures as an e‐commerce application. The work could be divided into two main parts. First, the development of a modeling methodology which can be used for automation of supplier selection procedures. By this modeling methodology, supplier selection procedures are divided into pre‐selection, selection and the post‐selection procedures. The selection procedure is further divided into the following stages: bidder selection, partner selection, and performance evaluation. The second part is about realization of automation. Three modules for automation are identified; they are the data collection system for bidder selection stage, the inference engine for partner selection stage, and the performance evaluation engine for the performance evaluation stage.
Managing the project management process
Authors: Czuchry Andrew J. , Yasin Mahmoud M.
Published: February 2003

The effective executive operating in today’s global environment must formulate, operate and execute across multi‐faceted environmental and organizational modes for different projects throughout their distinct phases in order to achieve results that meet shareholder expectations. In this study, the authors draw on a stream of research dealing with domestic and international project managers as well as the practical experience of the lead author to provide an informational integrated approach to help senior executives and project managers manage the strategic and operational facets of different projects. In this context, a practical roadmap for identifying problems and implementing timely corrective actions to improve projects’ success is advocated by this study.
Instant messaging reference: how does it compare?
Authors: Desai Christina M.
Published: February 2003

The use of instant messaging (IM) technology for providing online reference services is increasing by leaps and bounds. This article compares a digital reference service, Morris Messenger, with traditional, face‐to‐face reference, using quantitative and qualitative data from experience with this service at Morris Library, Southern Illinois University. The article addresses differences arising from the medium itself, differences in the categories of reference questions received, using several different categorization schemes, and differences in factors affecting willingness to return, to determine strengths and weaknesses of this medium. Since many libraries are considering implementing such a service, it also describes what it is like for staff to provide reference service this way and suggests ways of addressing some of the challenges of this new medium.
Forintek’s value added pathfinder: a case study
Authors: Holder B.
Published: February 2003

The paper describes the development of a specialised bilingual online database providing hyperlinks to Internet and other resources for researchers. The project grew from the need to provide current information for a new business area coinciding with the wish of the library staff to demonstrate leadership in knowledge management, making information accessible, no matter what its format or geographic location. Steps in planning the project are laid out. International standards for cataloguing electronic resources were not finalised, so the team adopted the best available for their purpose, building in enough flexibility to allow future adaptation. Our experience demonstrates the urgent need for finalised standards and led us to conclude that although consensus building is often desirable, sometimes there is a need to move forward more quickly with defined standards to prevent development stalling or extensive rework being required. Database elements, based on the Dublin Core metadata structure, are detailed.
Adoption of Internet for resource sharing by the Gulf academic libraries
Authors: Siddiqui Moid A.
Published: February 2003

Library services have been tremendously influenced by rapid technological innovations over the years. The Internet has virtually provided a new dimension to every area of library services and operations. Document delivery remained no exception to these changes. Besides looking at various Internet applications, the paper also examines available electronic document delivery (EDD) transmission systems using the Internet, such as the ARIEL system of Research Libraries Information Network (RLIN), the North Carolina State University Digitized Document Transmission Project (DDTP), and the Ohio State University Network Fax Project. The paper also presents the results of a survey conducted to determine the availability of required hardware and software in the Gulf academic libraries to use the Internet for EDD. The survey confirmed the availability of required equipment in the Gulf academic libraries and their willingness to participate in the EDD. Their adoption of the Internet for EDD for resource sharing is essential if user self‐sufficiency is to be achieved.
Export information use in small and medium‐sized industrial companies
Authors: Williams Jasmine E.M.
Published: February 2003

This study focuses on the use of export marketing information in small and medium‐sized enterprises (SMEs), an area that has previously attracted little academic research attention. It reports on the application of scales measuring instrumental/conceptual and symbolic export information use, using a random sample of UK exporters, to SME exporters of engineering and IT products. The results show that the scales are applicable within the specific context of the industrial SMEs surveyed and that levels of symbolic export information use are higher in these SMEs than in UK exporting companies as a whole. The latter is explained as a function of a shortfall in two areas: first, in available export marketing information, leading to greater dependence on “guesswork” and intuition; and second, in specialist marketing information‐processing skills on the part of SME export decision makers. The article concludes by appealing for an extension of export support for SMEs, to include the use of export information as well as simply its acquisition. It suggests that the scales tested here could be used both to diagnose the need for such SME support and to measure its effectiveness.
Statistical choices and apparent work outcomes in auditing
Authors: Picheng Lee Phil , Kleinman Gary
Published: February 2003

The public accounting sector of the accounting profession has long been very concerned with the problem of employee recruitment and retention. As early as the 1970s, the then Big 8 firms funded extensive studies of the determinants of employee turnover. The problem is no less real today. Indeed, much has been written about the problem of the vanishing accounting student. If reducing employee turnover and dissatisfaction becomes important in order for the public accounting firms to fulfill their mission of helping to assure the quality of information that investors receive, then having tools that foster an understanding of the determinants of employee dissatisfaction, stress, and turnover is vital. Sheds light on these issues by demonstrating how sophisticated statistical techniques can illuminate the underlying determinants of employee turnover and other important job attitudes. Applies structural equation modeling to Collins and Killough's dataset in order to demonstrate how it can provide important additional substantive insights about relationships between the stressors and job outcomes in public accounting. This important interpretive information is not available, or is available in only limited fashion, in the comparison method of canonical correlation analysis.
When weaker brands prevail
Authors: Lange Fredrik , Selander Sara , Åberg Catherine
Published: February 2003

When consumers fulfill consumption goals they make decisions on first, from which product category to buy, and second, which brand to purchase within the product category. In this article, the relative effects of product‐level typicality and brand‐level typicality on goal‐driven consumer choice are examined. Which level of typicality is more diagnostic of choice? Empirical results show that consumers are, in goal‐derived usage contexts, more likely to choose a less typical and less favored brand from a typical product category than a typical and more favored brand from a less typical product category. Consequently, brands that consumers perceive as inferior may be chosen over superior brands because of the link between product categories and usage contexts. Our results indicate that it may be fruitful for marketers to associate brands and product categories with usage contexts, and that they need to consider brand competitors from other product categories.
Foraging Adaptation and the Relationship Between Food-Web Complexity and Stability
Authors: Kondoh Michio
Published: February 2003

Ecological theory suggests that complex food webs should not persist because of their inherent instability. “Real” ecosystems often support a large number of interacting species. A mathematical model shows that fluctuating short-term selection on trophic links, arising from a consumer's adaptive food choice, is a key to the long-term stability of complex communities. Without adaptive foragers, food-web complexity destabilizes community composition; whereas in their presence, complexity may enhance community persistence through facilitation of dynamical food-web reconstruction that buffers environmental fluctuations. The model predicts a linkage pattern consistent with field observations.
Aging and Genome Maintenance: Lessons from the Mouse?
Authors: Hasty Paul , Campisi Judith , Hoeijmakers Jan , van Steeg Harry , Vijg Jan
Published: February 2003

Recent progress in the science of aging is driven largely by the use of model systems, ranging from yeast and nematodes to mice. These models have revealed conservation in genetic pathways that balance energy production and its damaging by-products with pathways that preserve somatic maintenance. Maintaining genome integrity has emerged as a major factor in longevity and cell viability. Here we discuss the use of mouse models with defects in genome maintenance for understanding the molecular basis of aging in humans.
Role of EDEM in the Release of Misfolded Glycoproteins from the Calnexin Cycle
Authors: Molinari Maurizio , Calanca Verena , Galli Carmela , Lucca Paola , Paganetti Paolo
Published: February 2003

The mechanisms that determine how folding attempts are interrupted to target folding-incompetent proteins for endoplasmic reticulum–associated degradation (ERAD) are poorly defined. Here the α-mannosidase I–like protein EDEM was shown to extract misfolded glycoproteins, but not glycoproteins undergoing productive folding, from the calnexin cycle. EDEM overexpression resulted in faster release of folding-incompetent proteins from the calnexin cycle and earlier onset of degradation, whereas EDEM down-regulation prolonged folding attempts and delayed ERAD. Up-regulation of EDEM during ER stress may promote cell recovery by clearing the calnexin cycle and by accelerating ERAD of terminally misfolded polypeptides.
To Write a Book, To Plant a Tree...
Authors: Bush Ashley I.
Published: February 2003

Losing My Mind
An Intimate Look at Life with Alzheimer's. Thomas DeBaggio. Free Press, New York, 2002. 219 pp. $24, C$36.50. ISBN 0-7432-0565-0. Paper, 222 pp. $13, C$21. ISBN 0-7432-0566-9. Large print, Thorndike, Waterville, ME. 352 pp. $27.95. ISBN 0-7862-4376-7.

DeBaggio provides a harrowing first-hand account of the progress of Alzheimer's disease.
Phylogenetic Shadowing of Primate Sequences to Find Functional Regions of the Human Genome
Authors: Boffelli Dario , McAuliffe Jon , Ovcharenko Dmitriy , Lewis Keith D. , Ovcharenko Ivan , Pachter Lior , Rubin Edward M.
Published: February 2003

Nonhuman primates represent the most relevant model organisms to understand the biology of
Homo sapiens
. The recent divergence and associated overall sequence conservation between individual members of this taxon have nonetheless largely precluded the use of primates in comparative sequence studies. We used sequence comparisons of an extensive set of Old World and New World monkeys and hominoids to identify functional regions in the human genome. Analysis of these data enabled the discovery of primate-specific gene regulatory elements and the demarcation of the exons of multiple genes. Much of the information content of the comprehensive primate sequence comparisons could be captured with a small subset of phylogenetically close primates. These results demonstrate the utility of intraprimate sequence comparisons to discover common mammalian as well as primate-specific functional elements in the human genome, which are unattainable through the evaluation of more evolutionarily distant species.
The Endocrine Regulation of Aging by Insulin-like Signals
Authors: Tatar Marc , Bartke Andrzej , Antebi Adam
Published: February 2003

Reduced signaling of insulin-like peptides increases the life-span of nematodes, flies, and rodents. In the nematode and the fly, secondary hormones downstream of insulin-like signaling appear to regulate aging. In mammals, the order in which the hormones act is unresolved because insulin, insulin-like growth factor–1, growth hormone, and thyroid hormones are interdependent. In all species examined to date, endocrine manipulations can slow aging without concurrent costs in reproduction, but with inevitable increases in stress resistance. Despite the similarities among mammals and invertebrates in insulin-like peptides and their signal cascade, more research is needed to determine whether these signals control aging in the same way in all the species by the same mechanism.
To Sir2, with Love
Authors: Promislow Daniel
Published: February 2003

Ageless Quest
One Scientist's Search for Genes That Prolong Youth. Lenny Guarente. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New York, 2002. 164 pp. $19.95. ISBN 0-87969- 652-4.

In this short book targeted at a popular audience, Guarente considers aging a disease and offers a very personal account of "the pursuit of a genetic 'cure' for aging."
Homo erectus
Calvarium from the Pleistocene of Java
Authors: Baba Hisao , Aziz Fachroel , Kaifu Yousuke , Suwa Gen , Kono Reiko T. , Jacob Teuku
Published: February 2003

A
Homo erectus
calvarium [Sambungmacan 4 (Sm 4)] was recovered from Pleistocene sediments at Sambungmacan in central Java. Micro–computed tomography analysis shows a modern human–like cranial base flexion associated with a low platycephalic vault, implying that the evolution of human cranial globularity was independent of cranial base flexion. The overall morphology of Sm 4 is intermediate between that of earlier and later Javanese
Homo erectus
; apparent morphological specializations are more strongly expressed in the latter. This supports the hypothesis that later Pleistocene Javanese populations were substantially isolated and made minimal contributions to the ancestry of modern humans.
Genetics and the Specificity of the Aging Process
Authors: Hekimi Siegfried , Guarente Leonard
Published: February 2003

The identification and study of long-lived mutant animals has provided valuable insights into the mechanisms that limit the life-span of organisms. Findings with the gene
SIR2
suggest that the rate of aging can be regulated under certain conditions. Indeed, increased expression of
SIR2
lengthens life-span by acting on biological processes that promote survival under conditions of scarcity. In addition, studies of mutant strains of
Caenorhabditis elegans
, in particular
daf-2
,
clk-1
, and
isp-1
mutants, suggest that the biology of reactive oxygen species in the mitochondria and elsewhere might be the main determinant of life-span in this organism. Thus, the aging process may be more specific than previously anticipated on evolutionary grounds.
Induction of Apoptosis by Paramyxovirus Simian Virus 5 Lacking a Small Hydrophobic Gene
Authors: Lin Yuan , Bright Angela C. , Rothermel Terri A. , He Biao
Published: February 2003

Simian virus 5 (SV5) is a member of the paramyxovirus family, which includes emerging viruses such as Hendra virus and Nipah virus as well as many important human and animal pathogens that have been known for years. SV5 encodes eight known viral proteins, including a small hydrophobic integral membrane protein (SH) of 44 amino acids. SV5 without the SH gene (rSV5ΔSH) is viable, and growth of rSV5ΔSH in tissue culture cells and viral protein and mRNA production in rSV5ΔSH-infected cells are indistinguishable from those of the wild-type SV5 virus. However, rSV5ΔSH causes increased cytopathic effect (CPE) and apoptosis in MDBK cells and is attenuated in vivo, suggesting the SH protein plays an important role in SV5 pathogenesis. How rSV5ΔSH induces apoptosis in infected cells has been examined in this report. Tumor necrosis factor alpha (TNF-α), a proinflammatory cytokine, was detected in culture media of rSV5ΔSH-infected cells. Apoptosis induced by rSV5ΔSH was inhibited by neutralizing antibodies against TNF-α and TNF-α receptor 1 (TNF-R1), suggesting that TNF-α played an essential role in rSV5ΔSH-induced apoptosis in a TNF-R1-dependent manner. Examination of important proteins in the TNF-α signaling pathway showed that p65, a major NF-κB subunit whose activation can lead to transcription of TNF-α, was first translocated to the nucleus and was capable of binding to DNA and then was targeted for degradation in rSV5ΔSH-infected cells while expression levels of TNF-R1 remained relatively constant. Thus, rSV5ΔSH induced cell death by activating TNF-α expression, possibly through activation of the NF-κB subunit p65 and then targeting p65 for degradation, leading to apoptosis.
Retroviruses Have Differing Requirements for Proteasome Function in the Budding Process
Authors: Ott David E. , Coren Lori V. , Sowder Raymond C. , Adams Julian , Schubert Ulrich
Published: February 2003

Proteasome inhibitors reduce the budding of human immunodeficiency virus types 1 (HIV-1) and 2, simian immunodeficiency virus, and Rous sarcoma virus. To investigate this effect further, we examined the budding of other retroviruses from proteasome inhibitor-treated cells. The viruses tested differed in their Gag organization, late (L) domain usage, or assembly site from those previously examined. We found that proteasome inhibition decreased the budding of murine leukemia virus (plasma membrane assembly, PPPY L domain) and Mason-Pfizer monkey virus (cytoplasmic assembly, PPPY L domain), similar to the reduction observed for HIV-1. Thus, proteasome inhibitors can affect the budding of a virus that assembles within the cytoplasm. However, the budding of mouse mammary tumor virus (MMTV; cytoplasmic assembly, unknown L domain) was unaffected by proteasome inhibitors, similar to the proteasome-independent budding previously observed for equine infectious anemia virus (plasma membrane assembly, YPDL L domain). Examination of MMTV particles detected Gag-ubiquitin conjugates, demonstrating that an interaction with the ubiquitination system occurs during assembly, as previously found for other retroviruses. For all of the cell lines tested, the inhibitor treatment effectively inactivated proteasomes, as measured by the accumulation of polyubiquitinated proteins. The ubiquitination system was also inhibited, as evidenced by the loss of monoubiquitinated histones from treated cells. These results and those from other viruses show that proteasome inhibitors reduce the budding of viruses that utilize either a PPPY- or PTAP-based L domain and that this effect does not depend on the assembly site or the presence of monoubiquitinated Gag in the virion.
Glial Cell-Specific Regulation of the JC Virus Early Promoter by Histone Deacetylase Inhibitors
Authors: Kim So-Young , Woo Moon-Sook , Kim Won-Ki , Choi Eung-Chil , Henson John W. , Kim Hee-Sun
Published: February 2003

The human polyomavirus JC virus is the etiologic agent of the fatal disease demyelinating progressive multifocal leukoencephalopathy. Although multiple transcription factors have been shown to interact with the JC virus promoter and regulate transcriptional activity, their relevance to cell specificity remains elusive. To investigate whether chromatin structure controls glial cell-specific expression of JC virus early genes, glial and nonglial cells were transfected with a reporter plasmid containing the JC virus early promoter and then treated with the histone deacetylase (HDAC) inhibitors trichostatin A (TSA) and sodium butyrate. TSA and butyrate induced 20- to 30-fold activation of the JC virus promoter in nonglial cells, whereas less than 2-fold induction was observed in glial cells. These results indicate that the JC virus early promoter might be highly suppressed in nonglial cells by hypoacetylated chromatin and activated by hyperacetylation. In support of this, chromatin immunoprecipitation assays demonstrated acetylation of the JC virus promoter region in U87MG cells but no acetylation in HeLa cells. In addition, treatment of HeLa cells with TSA induced hyperacetylation of the JC virus promoter, whereas minimal induction was seen in U87MG cells. Deletional and site-directed mutational analyses revealed that the enhancer region and Sp1 binding site upstream of the TATA box were important for TSA-mediated activation. We confirmed TSA-mediated activation of the JC virus promoter in the context of natural chromatin structure in stable cell lines. Thus, it appears that chromatin structure may control JC virus transcription in a cell-specific manner.
Loss of the Perforin Cytotoxic Pathway Predisposes Mice to Experimental Cytomegalovirus Retinitis
Authors: Dix Richard D. , Podack Eckhard R. , Cousins Scott W.
Published: February 2003

AIDS-related human cytomegalovirus (HCMV) retinitis continues to be a chronic ophthalmologic problem among human immunodeficiency virus type 1 (HIV-1)-infected patients who do not respond to highly active antiretroviral therapy. Although HCMV retinitis occurs during HIV-1-induced immunosuppression, the precise effector mechanism(s) that fails during the immunopathogenesis of AIDS to allow onset and progression of HCMV retinal disease remains unclear. We therefore performed a series of experiments to explore the relative roles of distinct pathways of lymphocyte-mediated cytotoxicity in either resistance or susceptibility to experimental murine cytomegalovirus (MCMV) retinitis in mice. Whereas mutant C57BL/6 mice deficient in the Fas/FasL cytotoxic pathway (gldmice) were identical to normal C57BL/6 mice and exhibited absolute resistance to retinal necrosis following subretinal MCMV inoculation, knockout C57BL/6 mice deficient in the perforin cytotoxic pathway (PKO mice) were susceptible to MCMV retinitis. Susceptibility of PKO mice to MCMV retinitis correlated with increased ocular MCMV titers when compared with ocular MCMV titers ofgldand normal mice. Since mice with retrovirus-induced immunodeficiency syndrome (MAIDS) exhibited a frequency and severity of MCMV retinitis that were equivalent to those observed in PKO mice, we hypothesized that susceptibility to MCMV retinitis during MAIDS correlates with a decrease in the perforin cytotoxic pathway. To test this hypothesis, we developed a quantitative competitive reverse transcription-PCR assay to measure mouse perforin mRNA levels in the splenic T lymphocytes and MCMV-inoculated eyes of normal mice or mice with MAIDS. Perforin mRNA levels in splenic T lymphocytes were significantly decreased during MAIDS, by ∼100-fold, from perforin mRNA levels in normal mice. Moreover, MCMV-inoculated eyes destined to develop retinitis during MAIDS also showed a significant decrease in perforin mRNA levels from the perforin mRNA levels of MCMV-inoculated eyes of normal mice destined to be resistant to retinitis. As expected, perforin mRNA could not be detected in unmanipulated and uninfected eyes of normal mice. These results provide the first evidence that the perforin cytotoxic pathway is more important than the Fas/FasL cytotoxic pathway in providing resistance to experimental MCMV retinitis and that loss of the perforin cytotoxic pathway predisposes to MCMV retinitis.
Strain-Dependent Structural Variants of Herpes Simplex Virus Type 1 ICP34.5 Determine Viral Plaque Size, Efficiency of Glycoprotein Processing, and Viral Release and Neuroinvasive Disease Potential
Authors: Mao Hanwen , Rosenthal Ken S.
Published: February 2003

The ability of certain strains of herpes simplex virus type 1 (HSV-1) to cause encephalitis or neuroinvasive disease in the mouse upon peripheral infection is dependent on a combination of activities of specific forms of viral proteins. The importance of specific variants of ICP34.5 to neuroinvasive disease potential and its correlation with small-plaque production, inefficient glycoprotein processing, and virus release were suggested by comparison of ICP34.5 from the SP7 virus, originally obtained from the brain of a neonate with disseminated disease, and the tissue culture-passaged progeny of SP7 (SLP5 and SLP10) and the KOS321 virus. SLP5, SLP10, and KOS321 are attenuated and exhibit a large-plaque phenotype, including efficient glycoprotein processing and viral release. We show that expression of the KOS321 ICP34.5 protein in cells infected with SP7 or ICP34.5 deletion mutants promotes large plaque formation and efficient viral glycoprotein processing, while expression of the SP7 ICP34.5 protein decreases efficiency of viral glycoprotein processing. In addition, a recombinant virus, 4hS1, with the SP7 ICP34.5 gene replacing the KOS321-like ICP34.5 gene in the SLP10a background, rescues the small-plaque phenotype and neuroinvasive disease. The major difference in the ICP34.5 gene product is the number of Pro-Ala-Thr repeats in the middle region of the protein, with 18 for SP7 and 3 for KOS321. Strain-dependent differences in the ICP34.5 protein can therefore alter the tissue culture behavior and the virulence of HSV-1.
Vaccinia Virus G7L Protein Interacts with the A30L Protein and Is Required for Association of Viral Membranes with Dense Viroplasm To Form Immature Virions
Authors: Szajner Patricia , Jaffe Howard , Weisberg Andrea S. , Moss Bernard
Published: February 2003

The vaccinia virus A30L protein is required for the association of electron-dense, granular, proteinaceous material with the concave surfaces of crescent membranes, an early step in viral morphogenesis. For the identification of additional proteins involved in this process, we used an antibody to the A30L protein, or to an epitope appended to its C terminus, to capture complexes from infected cells. A prominent 42-kDa protein was resolved and identified by mass spectrometry as the vaccinia virus G7L protein. This previously uncharacterized protein was expressed late in infection and was associated with immature virions and the cores of mature particles. In order to study the role of the G7L protein, a conditional lethal mutant was made by replacing the G7L gene with an inducible copy. Expression of G7L and formation of infectious virus was dependent on the addition of inducer. Under nonpermissive conditions, morphogenesis was blocked and viral crescent membranes and immature virions containing tubular elements were separated from the electron-dense granular viroplasm, which accumulated in large spherical masses. This phenotype was identical to that previously obtained with an inducible, conditional lethal A30L mutant. Additional in vivo and in vitro experiments provided evidence for the direct interaction of the A30L and G7L proteins and demonstrated that the stability of each one was dependent on its association with the other.
Measles Virus Infects and Suppresses Proliferation of T Lymphocytes from Transgenic Mice Bearing Human Signaling Lymphocytic Activation Molecule
Authors: Hahm Bumsuk , Arbour Nathalie , Naniche Denise , Homann Dirk , Manchester Marianne , Oldstone Michael B. A.
Published: February 2003

Humans are the only natural reservoir of measles virus (MV), one of the most contagious viruses known. MV infection and the profound immunosuppression it causes are currently responsible for nearly one million deaths annually. Human signaling lymphocytic activation molecule (hSLAM) was identified as a receptor for wild-type MV as well as for MV strains prepared as vaccines. To better evaluate the role of hSLAM in MV pathogenesis and MV-induced immunosuppression, we created transgenic (tg) mice that expressed the hSLAM molecule under the control of thelckproximal promoter. hSLAM was expressed on CD4+and CD8+T cells in the blood and spleen and also on CD4+, CD8+, CD4+CD8+, and CD4−CD8−thymocytes. Wild-type MV, after limited passage on B95-8 marmoset B cells, and the Edmonston laboratory strain of MV infected hSLAM-expressing cells. There was a direct correlation between the amount of hSLAM expressed on the cells' surface and the degree of viral infection. Additionally, MV infection induced downregulation of receptor hSLAM and inhibited cell division and proliferation of hSLAM+but not hSLAM−T cells. Therefore, these tg mice provide the opportunity for analyzing and comparing MV-T cell interactions and MV pathogenesis in cells expressing only the hSLAM MV receptor with those of tg mice whose T cells selectively express another MV receptor, CD46.
The Stable 2.0-Kilobase Intron of the Herpes Simplex Virus Type 1 Latency-Associated Transcript Does Not Function as an Antisense Repressor of ICP0 in Nonneuronal Cells
Authors: Burton Edward A. , Hong Chang-Sook , Glorioso Joseph C.
Published: February 2003

During latency, herpes simplex virus expresses a unique set of latency-associated transcripts (LATs). As the 2.0-kb LAT intron is complementary to, and overlaps, the 3′ end of the ICP0 transcript, it has been suggested that the stable LAT intron might function as an antisense repressor of ICP0 expression. We tested this hypothesis in cell culture by dissociating
cis
- and
trans
-acting effects of the 2.0-kb LAT, using a series of complementary strategies. Initially, we constructed 293T cell lines that stably express the nuclear 2.0-kb LAT intron to determine whether LAT accumulation in
trans
affects ICP0 expression. ICP0 mRNA and protein expression profiles were studied (i) following infections with a viral mutant containing wild-type LAT and ICP0 sequences but having deletions of other immediate-early (IE) genes, thus preventing the progression of viral early gene expression, (ii) at early time points after infection with wild-type virus, before viral LAT expression, and (iii) by plasmid transfections. Northern and Western blot analysis showed that
trans
expression of the 2.0-kb LAT intron does not affect ICP0 mRNA expression, stability, accumulation, splicing, or translation. In addition, suppression of viral replication by overexpression of the 2.0-kb LAT, which has been detected previously in neuronal cell lines, was not found in these nonneuronal cell lines. However, deletion of the latency-active promoter (LAP) region of the virus resulted in overexpression of IE genes, which occurred soon after infection, before viral LAT expression had commenced. This was not complemented by the expression of LAT in
trans
, suggesting that the LAP deletion affected transcriptional regulation of the IE genes in
cis
. We conclude that the function of the highly conserved LAT intron is unlikely to involve a direct-acting anti-ICP0 antisense mechanism but that the LAT region could affect ICP0 mRNA expression from the viral genome.
3′ Nontranslated RNA Signals Required for Replication of Hepatitis C Virus RNA
Authors: Yi MinKyung , Lemon Stanley M.
Published: February 2003

We describe a mutational analysis of the 3′ nontranslated RNA (3′NTR) signals required for replication of subgenomic hepatitis C virus (HCV) RNAs. A series of deletion mutants was constructed within the background of an HCV-N replicon that induces the expression of secreted alkaline phosphatase in order to examine the requirements for each of the three domains comprising the 3′NTR, namely, the highly conserved 3′ terminal 98-nucleotide (nt) segment (3′X), an upstream poly(U)-poly(UC) [poly(U/UC)] tract, and the variable region (VR) located at the 5′ end of the 3′NTR. Each of these domains was found to contribute to efficient replication of the viral RNA in transiently transfected hepatoma cells. Replication was not detected when any of the three putative stem-loop structures within the 3′X region were deleted. Similarly, complete deletion of the poly(U/UC) tract abolished replication. Replacement of a minimum of 50 to 62 nt of poly(U/UC) sequence was required for detectable RNA replication when the native sequence was restored in a stepwise fashion from its 3′ end. Lengthier poly(U/UC) sequences, and possibly pure homopolymeric poly(U) tracts, were associated with more efficient RNA amplification. Finally, while multiple deletion mutations were tolerated within VR, each led to a partial loss of replication capacity. The impaired replication capacity of the deletion mutants could not be explained by reduced translational activity or by decreased stability of the RNA, suggesting that each of these mutations may impair recognition of the RNA by the viral replicase during an early step in negative-strand RNA synthesis. The results indicate that the 3′-most 150 nt of the HCV-N genome [the 3′X region and the 3′ 52 nt of the poly(U/UC) tract] contain RNA signals that are essential for replication, while the remainder of the 3′NTR plays a facilitating role in replication but is not absolutely required.
Protein Synthesis and Endoplasmic Reticulum Stress Can Be Modulated by the Hepatitis C Virus Envelope Protein E2 through the Eukaryotic Initiation Factor 2α Kinase PERK
Authors: Pavio Nicole , Romano Patrick R. , Graczyk Thomas M. , Feinstone Stephen M. , Taylor Deborah R.
Published: February 2003

The hepatitis C virus envelope protein, E2, is an endoplasmic reticulum (ER)-bound protein that contains a region of sequence homology with the double-stranded RNA-activated protein kinase PKR and its substrate, the eukaryotic translation initiation factor 2 (eIF2). We previously reported that E2 modulates global translation through inhibition of the interferon-induced antiviral protein PKR through its PKR-eIF2α phosphorylation site homology domain (PePHD). Here we show that the PKR-like ER-resident kinase (PERK) binds to and is also inhibited by E2. At low expression levels, E2 induced ER stress, but at high expression levels, and in vitro, E2 inhibited PERK kinase activity. Mammalian cells that stably express E2 were refractory to the translation-inhibitory effects of ER stress inducers, and E2 relieved general translation inhibition induced by PERK. The PePHD of E2 was required for the rescue of translation that was inhibited by activated PERK, similar to our previous findings with PKR. Here we report the inhibition of a second eIF2α kinase by E2, and these results are consistent with a pseudosubstrate mechanism of inhibition of eIF2α kinases. These findings may also explain how the virus promotes persistent infection by overcoming the cellular ER stress response.
The Human Cytomegalovirus Major Immediate-Early Enhancer Determines the Efficiency of Immediate-Early Gene Transcription and Viral Replication in Permissive Cells at Low Multiplicity of Infection
Authors: Isomura Hiroki , Stinski Mark F.
Published: February 2003

To determine the effect of the human cytomegalovirus (CMV) major immediate-early (MIE) enhancer or promoter on the efficiency of viral replication in permissive human cells, we constructed recombinant viruses with their human MIE promoter, enhancer, and promoter plus enhancer replaced with the murine CMV components. After a low multiplicity of infection (MOI) (0.01 PFU/cell), recombinant human CMV with the murine CMV promoter replicated like the wild type but recombinant virus with the murine enhancer replicated less efficiently. Immediate-early (IE) viral protein pIE72 (UL123), early viral protein (UL44), and viral DNA synthesis were significantly decreased. The effect of the human CMV enhancer substitution with the murine CMV enhancer was also demonstrated in different cell types by using recombinant virus with the UL127 promoter, driving the expression of green fluorescent protein (GFP). After an MOI of 1, GFP expression was high with the human CMV enhancer and significantly lower with the murine CMV enhancer. Even though at a high MOI (10 PFU/cell), the murine CMV enhancer was as efficient as the human CMV enhancer for the transcription of IE genes in human foreskin fibroblast cells, at lower MOIs, the murine CMV enhancer was less efficient. Proximal and distal chimeras of the human and murine enhancers also replicated less efficiently at a low MOI and expressed lower levels of GFP from the UL127 promoter. These experiments demonstrate that the entire human CMV enhancer has evolved for the efficient expression of the viral IE and early genes in human cells. Possible functions of the human CMV enhancer and promoter at a low MOI are discussed.