bluuebunny/crossref_metadata_2025 huggingface dataset:
Importance of Receptor Usage,
Fli1
Activation, and Mouse Strain for the Stem Cell Specificity of 10A1 Murine Leukemia Virus Leukemogenicity
Authors: Rodenburg Michaela , Fischer Meike , Engelmann Afra , Harbers Stephanie O. , Ziegler Marion , Löhler Jürgen , Stocking Carol
Published: December 2006

Murine leukemia viruses (MuLV) induce leukemia through a multistage process, a critical step being the activation of oncogenes through provirus integration. Transcription elements within the long terminal repeats (LTR) are prime determinants of cell lineage specificity; however, the influence of other factors, including the Env protein that modulates cell tropism through receptor recognition, has not been rigorously addressed. The ability of 10A1-MuLV to use both PiT1 and PiT2 receptors has been implicated in its induction of blast cell leukemia. Here we show that restricting receptor usage of 10A1-MuLV to PiT2 results in loss of blast cell transformation capacity. However, the pathogenicity was unaltered when the
env
gene is exchanged with Moloney MuLV, which uses the Cat1 receptor. Significantly, the leukemic blasts express erythroid markers and consistently contain proviral integrations in the
Fli1
locus, a target of Friend MuLV (F-MuLV) during erythroleukemia induction. Furthermore, an NB-tropic variant of 10A1 was unable to induce blast cell leukemia in C57BL/6 mice, which are also resistant to F-MuLV transformation. We propose that 10A1- and F-MuLV actually induce identical (erythro)blastic leukemia by a mechanism involving Fli1 activation and cooperation with inherent genetic mutations in susceptible mouse strains. Furthermore, we demonstrate that deletion of the
Icsbp
tumor suppressor gene in C57BL/6 mice is sufficient to confer susceptibility to 10A1-MuLV leukemia induction but with altered specificity. In summary, we validate the significance of the
env
gene in leukemia specificity and underline the importance of a complex interplay of cooperating oncogenes and/or tumor suppressors in determining the pathogenicity of MuLV variants.
Viral Infection of the Lungs through the Eye
Authors: Bitko Vira , Musiyenko Alla , Barik Sailen
Published: December 2006

Respiratory syncytial virus (RSV) is the foremost respiratory pathogen in newborns and claims millions of lives annually. However, there has been no methodical study of the pathway(s) of entry of RSV or its interaction with nonrespiratory tissues. We and others have recently established a significant association between allergic conjunctivitis and the presence of RSV in the eye. Here we adopt a BALB/c mouse model and demonstrate that when instilled in the live murine eye, RSV not only replicated robustly in the eye but also migrated to the lung and produced a respiratory disease that is indistinguishable from the standard, nasally acquired RSV disease. Ocularly applied synthetic anti-RSV small interfering RNA prevented infection of the eye as well as the lung. RSV infection of the eye activated a plethora of ocular cytokines and chemokines with profound relevance to inflammation of the eye. Anticytokine treatments in the eye reduced ocular inflammation but had no effect on viral growth in both eye and lung, demonstrating a role of the cytokine response in ocular pathology. These results establish the eye as a major gateway of respiratory infection and a respiratory virus as a bona fide eye pathogen, thus offering novel intervention and treatment options.
Varicella-Zoster Virus Infection of Human Fibroblast Cells Activates the c-Jun N-Terminal Kinase Pathway
Authors: Zapata Heidi J. , Nakatsugawa Masako , Moffat Jennifer F.
Published: December 2006

The transcription factors ATF-2 and c-Jun are important for transactivation of varicella-zoster virus (VZV) genes. c-Jun is activated by the c-Jun N-terminal kinase (JNK), a member of the mitogen-activated protein kinase pathway that responds to stress and cytokines. To study the effects of VZV on this pathway, confluent human foreskin fibroblasts were infected with cell-associated VZV for 1 to 4 days. Immunoblots showed that phosphorylated JNK and c-Jun levels increased in VZV-infected cells, and kinase assays determined that phospho-JNK was active. Phospho-JNK was detected after 24 h, and levels rose steadily over 4 days in parallel with accumulation of VZV antigen. The two main activators of JNK are MKK4 and MKK7, and levels of their active, phosphorylated forms also increased. The competitive inhibitor of JNK, SP600125, caused a dose-dependent reduction in VZV yield (50% effective concentration, ≅8 μM). Specificity was verified by immunoblotting; phospho-c-Jun was eliminated by 18 μM SP600125 in VZV-infected cells. Immunofluorescent confocal microscopy showed that phospho-c-Jun and most of phospho-JNK were in the nuclei of VZV-infected cells; some phospho-JNK was in the cytoplasm. MKK4, MKK7, JNK, and phospho-JNK were detected by immunoblotting in purified preparations of VZV virions, but c-Jun was absent. JNK was located in the virion tegument, as determined by biochemical fractionation and immunogold transmission electron microscopy. Overall, these results demonstrate the importance of the JNK pathway for VZV replication and advance the idea that JNK is a useful drug target against VZV.
Small Interfering RNA Targeted to Hepatitis C Virus 5′ NontranslatedRegion Exerts Potent Antiviral Effect
Authors: Kanda Tatsuo , Steele Robert , Ray Ranjit , Ray Ratna B.
Published: December 2006

Hepatitis C virus (HCV) is a major cause of cirrhosis and hepatocellular carcinoma. Interferon alone or together with ribavirin is the only therapy for HCV infection; however, a significant number of HCV-infected individuals do not respond to this treatment. Therefore, the development of new therapeutic options against HCV is a matter of urgency. In the present study, we have examined vectors carrying short hairpin RNA (shRNA) targeting the 5′ nontranslated conserved region of the HCV genome for inhibition of virus replication. Initially, three sequences were selected, and all three shRNAs (psh-53, psh-274, and psh-375) suppressed HCV internal ribosome entry site (IRES)-mediated translation to different degrees in Huh-7 cells. Next, we introduced siRNA into Huh-7.5 cells persistently infected with HCV genotype 2a (JFH1). The most efficient inhibition of JFH1 replication was observed with psh-274, targeted to the portion from subdomain IIId to IIIe of the IRES. Subsequently, Huh-7.5 cells stably expressing psh-274 further displayed a significant reduction in HCV JFH1 replication. The effect of psh-274 on cell-culture-grown HCV genotype 1a (H77) was also evaluated, and inhibition of virus replication and infectivity titers was observed. In the absence of a cell-culture-grown HCV genotype 1b, the effects of psh-274 on subgenomic and full-length replicons were examined, and efficient inhibition of genome replication was observed. Therefore, we have identified a conserved sequence targeted to the HCV genome that can inhibit replication of different genotypes, suggesting the potential of siRNA as an additional therapeutic modality against HCV infection.
Double-Stranded RNA Deaminase ADAR1 Increases Host Susceptibility to Virus Infection
Authors: Nie Yongzhan , Hammond Graeme L. , Yang Jing-Hua
Published: December 2006

The RNA-editing enzyme ADAR1 is a double-stranded RNA (dsRNA) binding protein that modifies cellular and viral RNA sequences by adenosine deamination. ADAR1 has been demonstrated to play important roles in embryonic erythropoiesis, viral response, and RNA interference. In human hepatitis virus infection, ADAR1 has been shown to target viral RNA and to suppress viral replication through dsRNA editing. It is not clear whether this antiviral effect of ADAR1 is a common mechanism in response to viral infection. Here, we report a proviral effect of ADAR1 that enhances replication of vesicular stomatitis virus (VSV) through a mechanism independent of dsRNA editing. We demonstrate that ADAR1 interacts with dsRNA-activated protein kinase PKR, inhibits its kinase activity, and suppresses the α subunit of eukaryotic initiation factor 2 (eIF-2α) phosphorylation. Consistent with the inhibitory effect on PKR activation, ADAR1 increases VSV infection in PKR
+/+
mouse embryonic fibroblasts; however, no significant effect was found in PKR
−/−
cells. This proviral effect of ADAR1 requires the N-terminal domains but does not require the deaminase domain. These findings reveal a novel mechanism of ADAR1 that increases host susceptibility to viral infection by inhibiting PKR activation.
The Level of CD81 Cell Surface Expression Is a Key Determinant for Productive Entry of Hepatitis C Virus into Host Cells
Authors: Koutsoudakis George , Herrmann Eva , Kallis Stephanie , Bartenschlager Ralf , Pietschmann Thomas
Published: December 2006

Recently a cell culture model supporting the complete life cycle of the hepatitis C virus (HCV) was developed. Searching for host cell determinants involved in the HCV replication cycle, we evaluated the efficiency of virus propagation in different Huh-7-derived cell clones. We found that Huh-7.5 cells and Huh7-Lunet cells, two former replicon cell clones that had been generated by removal of an HCV replicon by inhibitor treatment, supported comparable levels of RNA replication and particle production, whereas virus spread was severely impaired in the latter cells. Analysis of cell surface expression of CD81 and scavenger receptor class B type I (SR-BI), two molecules previously implicated in HCV entry, revealed similar expression levels for SR-BI, while CD81 surface expression was much higher on Huh-7.5 cells than on Huh7-Lunet cells. Ectopic expression of CD81 in Huh7-Lunet cells conferred permissiveness for HCV infection to a level comparable to that for Huh-7.5 cells. Modulation of CD81 cell surface density in Huh-7.5 cells by RNA interference indicated that a certain amount of this molecule (∼7 × 104molecules per cell) is required for productive infection with a low dose of HCV. Consistent with this, we show that susceptibility to HCV infection depends on a critical quantity of CD81 molecules. While infection is restricted in cells expressing very small amounts of CD81, susceptibility rapidly rises within a narrow range of CD81 levels, reaching a plateau where higher expression does not further increase the efficiency of infection. Together these data indicate that a high density of cell surface-exposed CD81 is a key determinant for productive HCV entry into host cells.
Bicistronic Woodchuck Hepatitis Virus Core and Gamma Interferon DNA Vaccine Can Protect from Hepatitis but Does Not Elicit Sterilizing Antiviral Immunity
Authors: Wang Jinguo , Gujar Shashi A. , Cova Lucyna , Michalak Tomasz I.
Published: December 2006

The immunity elicited against nucleocapsid of hepatitis B virus (HBV) and closely related woodchuck hepatitis virus (WHV) has been shown to be important in resolution of hepatitis and protection from infection. Further, activity of gamma interferon (IFN-γ), which may directly inhibit hepadnavirus replication, promotes antiviral defense and favors T helper cell type 1 (Th1) response, which is seemingly a prerequisite of HBV clearance. In this study, to enhance induction of protective immunity against hepadnavirus, healthy woodchucks were immunized with a bicistronic DNA vaccine carrying WHV core (WHc) and woodchuck IFN-γ (wIFN-γ) gene sequences. Three groups, each group containing three animals, were injected once or twice with 0.5 mg, 0.9 mg, or 1.5 mg per dose of this vaccine. In addition, four animals received two injections of 0.6 mg or 1 mg WHc DNA alone. All animals were challenged with WHV. The results showed that four of nine animals injected with the bicistronic vaccine and one of four immunized with WHc DNA became protected from serologically evident infection and hepatitis. This protection was not linked to induction of WHc antigen-specific antibodies or T-cell proliferative response and was not associated with enhanced transcription of Th1 cytokines or 2′,5′-oligoadenylate synthetase. Strikingly, all animals protected from hepatitis became reactive for WHV DNA and carried low levels of replicating virus in hepatic and lymphoid tissues after challenge with WHV. This study shows that the bicistronic DNA vaccine encoding both hepadnavirus core antigen and IFN-γ was more effective in preventing hepatitis than that encoding virus core alone, but neither of them could mount sterile immunity against the virus or prevent establishment of occult infection.
The ORF7b Protein of Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) Is Expressed in Virus-Infected Cells and Incorporated into SARS-CoV Particles
Authors: Schaecher Scott R. , Mackenzie Jason M. , Pekosz Andrew
Published: December 2006

Coronavirus replication is facilitated by a number of highly conserved viral proteins. The viruses also encode accessory genes, which are virus group specific and believed to play roles in virus replication and pathogenesis in vivo. Of the eight putative accessory proteins encoded by the severe acute respiratory distress syndrome associated coronavirus (SARS-CoV), only two—open reading frame 3a (ORF3a) and ORF7a—have been identified in virus-infected cells to date. The ORF7b protein is a putative viral accessory protein encoded on subgenomic (sg) RNA 7. The ORF7b initiation codon overlaps the ORF7a stop codon in a −1 shifted ORF. We demonstrate that the ORF7b protein is expressed in virus-infected cell lysates and from a cDNA encoding the gene 7 coding region, indicating that the sgRNA7 is bicistronic. The translation of ORF7b appears to be mediated by ribosome leaky scanning, and the protein has biochemical properties consistent with that of an integral membrane protein. ORF7b localizes to the Golgi compartment and is incorporated into SARS-CoV particles. We therefore conclude that the ORF7b protein is not only an accessory protein but a structural component of the SARS-CoV virion.
Immunogenic and Functional Organization of Hepatitis C Virus (HCV) Glycoprotein E2 on Infectious HCV Virions
Authors: Keck Zhen-Yong , Xia Jinming , Cai Zhaohui , Li Ta-Kai , Owsianka Ania M. , Patel Arvind H. , Luo Guangxiang , Foung Steven K. H.
Published: December 2006

Development of full-length hepatitis C virus (HCV) RNAs replicating efficiently and producing infectious cell-cultured virions, HCVcc, in hepatoma cells provides an opportunity to characterize immunogenic domains on viral envelope proteins involved in entry into target cells. A panel of immunoglobulin G1 human monoclonal antibodies (HMAbs) to three immunogenic conformational domains (designated A, B, and C) on HCV E2 glycoprotein showed that epitopes within two domains, B and C, mediated HCVcc neutralization, whereas HMAbs to domain A were all nonneutralizing. For the neutralizing antibodies to domain B (with some to conserved epitopes among different HCV genotypes), the inhibitory antibody concentration reducing HCVcc infection by 90%, IC
90
, ranged from 0.1 to 4 μg/ml. For some neutralizing HMAbs, HCVcc neutralization displayed a linear correlation with an antibody concentration between the IC
50
and the IC
90
while others showed a nonlinear correlation. The differences between IC
50
/IC
90
ratios and earlier findings that neutralizing HMAbs block E2 interaction with CD81 suggest that these antibodies block different facets of virus-receptor interaction. Collectively, these findings support an immunogenic model of HCV E2 having three immunogenic domains with distinct structures and functions and provide added support for the idea that CD81 is required for virus entry.
Prion Interference Is Due to a Reduction in Strain-Specific PrP
Sc
Levels
Authors: Bartz Jason C. , Kramer Michelle L. , Sheehan Meghan H. , Hutter Jessica A. L. , Ayers Jacob I. , Bessen Richard A. , Kincaid Anthony E.
Published: December 2006

When two prion strains infect a single host, one strain can interfere with the ability of the other to cause disease but it is not known whether prion replication of the second strain is also diminished. To further investigate strain interference, we infected hamsters in the sciatic nerve with the long-incubation-period transmissible mink encephalopathy (TME) agent DY TME prior to superinfection of hamsters with the short-incubation-period HY TME agent. Increases in the interval between TME agent inoculations resulted in an extension of the incubation period of HY TME or a complete block of the ability of the HY TME agent to cause disease. The sciatic nerve route of inoculation gave the two TME strains access to the same population of neurons, allowing for the potential of prion interference in the lumbar spinal cord. The ability of the DY TME agent to extend the incubation period of HY TME corresponds with detection of DY TME PrP
Sc
, the abnormal isoform of the prion protein, in the lumbar spinal cord. The increased incubation period of HY TME or the inability of the HY TME agent to cause disease in the coinfected animals corresponds with a reduction in the abundance of HY TME PrP
Sc
in the lumbar spinal cord. When the two strains were not directed to the same populations of neurons within the lumbar spinal cord, interference between HY TME and DY TME did not occur. This suggests that DY TME agent replication interferes with HY TME agent replication when the two strains infect a common population of neurons.
Glycoprotein M of Herpes Simplex Virus 1 Is Incorporated into Virions during Budding at the Inner Nuclear Membrane
Authors: Baines Joel D. , Wills Elizabeth , Jacob Robert J. , Pennington Janice , Roizman Bernard
Published: December 2006

It is widely accepted that nucleocapsids of herpesviruses bud through the inner nuclear membrane (INM), but few studies have been undertaken to characterize the composition of these nascent virions. Such knowledge would shed light on the budding reaction at the INM and subsequent steps in the egress pathway. The present study focuses on glycoprotein M (gM), a type III integral membrane protein of herpes simplex virus 1 (HSV-1) that likely contains eight transmembrane domains. The results indicated that gM localized primarily at the perinuclear region, with especially bright staining near the nuclear membrane (NM). Immunogold electron microscopic analysis indicated that, like gB and gD (M. R. Torrisi et al., J. Virol. 66:554-561, 1992), gM localized within both leaflets of the NM, the envelopes of nascent virions that accumulate in the perinuclear space, and the envelopes of cytoplasmic and mature extracellular virus particles. Indirect immunofluorescence studies revealed that gM colocalized almost completely with a marker of the Golgi apparatus and partially with a marker of the trans-Golgi network (TGN), whether or not these markers were displaced to the perinuclear region during infection. gM was also located in punctate extensions and invaginations of the NM induced by the absence of a viral kinase encoded by HSV-1 U
S
3 and within virions located in these extensions. Our findings therefore support the proposition that gM, like gB and gD, becomes incorporated into the virion envelope upon budding through the INM. The localization of viral glycoproteins and Golgi and TGN markers to a perinuclear region may represent a mechanism to facilitate the production of infectious nascent virions, thereby increasing the amount of infectivity released upon cellular lysis.
Role of Immunoproteasome Catalytic Subunits in the Immune Response to Hepatitis B Virus
Authors: Robek Michael D. , Garcia Mayra L. , Boyd Bryan S. , Chisari Francis V.
Published: December 2006

Inhibition of hepatitis B virus (HBV) replication and viral clearance from an infected host requires both the innate and adaptive immune responses. Expression of interferon (IFN)-inducible proteasome catalytic and regulatory subunits correlates with the IFN-α/β- and IFN-γ-mediated noncytopathic inhibition of HBV in transgenic mice and hepatocytes, as well as with clearance of the virus in acutely infected chimpanzees. The immunoproteasome catalytic subunits LMP2 and LMP7 alter proteasome specificity and influence the pool of peptides available for presentation by major histocompatibility complex class I molecules. We found that these subunits influenced both the magnitude and specificity of the CD8 T-cell response to the HBV polymerase and envelope proteins in immunized HLA-A2-transgenic mice. We also examined the role of LMP2 and LMP7 in the IFN-α/β- and IFN-γ-mediated inhibition of virus replication using HBV transgenic mice and found that they do not play a direct role in this process. These results demonstrate the ability of the IFN-induced proteasome catalytic subunits to shape the HBV-specific CD8 T-cell response and thus potentially influence the progression of infection to acute or chronic disease. In addition, these studies identify a potential key role for IFN in regulating the adaptive immune response to HBV through alterations in viral antigen processing.
Efficient Incorporation of Tegument Proteins pUL46, pUL49, and pUS3 into Pseudorabies Virus Particles Depends on the Presence of pUL21
Authors: Michael Kathrin , Klupp Barbara G. , Karger Axel , Mettenleiter Thomas C.
Published: December 2006

The mature virion of the alphaherpesvirus pseudorabies virus (PrV) contains a minimum of 31 structural proteins which are recruited into the virus particle by a network of protein-protein interactions which is only incompletely understood. We show here that deletion of the tegument protein pUL21 resulted in a drastic decrease in the incorporation of the pUL46, pUL49, and pUS3 tegument components into mature virions. Moreover, the attenuated PrV strain Bartha (PrV-Ba), which, among other defects, carries mutations in pUL21, also fails to package pUL46, pUL49, and pUS3 efficiently. By the reconstitution of wild-type pUL21 expression to PrV-Ba and the transfer of mutated PrV-Ba pUL21 into wild-type PrV, we demonstrate that this phenotype is due to the mutated pUL21.
Genetic Protection against Hepatitis B Virus Conferred byCCR5Δ32: Evidence that CCR5 Contributes to Viral Persistence
Authors: Thio Chloe L. , Astemborski Jacquie , Bashirova Arman , Mosbruger Timothy , Greer Spencer , Witt Mallory D. , Goedert James J. , Hilgartner Margaret , Majeske Audrey , O'Brien Stephen J. , Thomas David L. , Carrington Mary
Published: December 2006

Recovery from acute hepatitis B virus (HBV) infection requires a broad, vigorous T-cell response, which is enhanced in mice when chemokine receptor 5 (CCR5) is missing. To test the hypothesis that production of a nonfunctional CCR5 (CCR5Δ32[a functionally null allele containing a 32-bp deletion]) increases the likelihood of recovery from hepatitis B in humans, we studied 526 persons from three cohorts in which one person with HBV persistence was matched to two persons who recovered from an HBV infection. Recovery or persistence was determined prior to availability of lamivudine. We determined genotypes forCCR5Δ32and for polymorphisms in theCCR5promoter and in coding regions of the neighboring genes, chemokine receptor 2 (CCR2) and chemokine receptor-like 2 (CCRL2). Allele and haplotype frequencies were compared among the 190 persons with viral recovery and the 336 with persistence by use of conditional logistic regression.CCR5Δ32reduced the risk of developing a persistent HBV infection by nearly half (odds ratio [OR], 0.53; 95% confidence interval [CI], 0.33 to 0.83;P =0.006). This association was virtually identical in persons with and without a concomitant human immunodeficiency virus infection. Of the nine individuals who were homozygous for the deletion, eight recovered from infection (OR, 0.25; 95% CI, 0.03 to 1.99;P= 0.19). None of the other neighboring polymorphisms examined were associated with HBV outcome. These data demonstrate a protective effect ofCCR5Δ32in recovery from an HBV infection, provide genetic epidemiological evidence for a role of CCR5 in the immune response to HBV, and suggest a potential therapeutic treatment for patients persistently infected with HBV.
The Amino-Conserved Domain of Human Cytomegalovirus UL80a Proteins Is Required for Key Interactions during Early Stages of Capsid Formation and Virus Production
Authors: Loveland Amy N. , Nguyen Nang L. , Brignole Edward J. , Gibson Wade
Published: December 2006

Assembly of many spherical virus capsids is guided by an internal scaffolding protein or group of proteins that are often cleaved and eliminated in connection with maturation and incorporation of the genome. In cytomegalovirus there are at least two proteins that contribute to this scaffolding function; one is the maturational protease precursor (pUL80a), and the other is the assembly protein precursor (pUL80.5) encoded by a shorter genetic element within UL80a. Yeast GAL4 two-hybrid assays established that both proteins contain a carboxyl-conserved domain that is required for their interaction with the major capsid protein (pUL86) and an amino-conserved domain (ACD) that is required for their self-interaction and for their interaction with each other. In the work reported here, we demonstrate that when the ACD is deleted (δACD) or disrupted by a point mutation (L47A), the bacterially expressed mutant protein sediments as a monomer during rate-velocity centrifugation, whereas the wild-type protein sediments mainly as oligomers. We also show that the L47A mutation reduces the production of infectious virus by at least 90%, results in the formation of irregular nuclear capsids, gives rise to tube-like structures in the nucleus that resemble the capsid core in cross-section and contain UL80 proteins, slows nuclear translocation of the major capsid protein, and may slow cleavage by the maturational protease. We provide physical corroboration that mutating the ACD disrupts self-interaction of the UL80 proteins and biological support for the proposal that the ACD has a critical role in capsid assembly and production of infectious virus.
Adenoviruses Use Lactoferrin as a Bridge for CAR-Independent Binding to and Infection of Epithelial Cells
Authors: Johansson Cecilia , Jonsson Mari , Marttila Marko , Persson David , Fan Xiao-Long , Skog Johan , Frängsmyr Lars , Wadell Göran , Arnberg Niklas
Published: December 2006

Most adenoviruses bind to the coxsackie- and adenovirus receptor (CAR). Surprisingly, CAR is not expressed apically on polarized cells and is thus not easily available to viruses. Consequently, alternative mechanisms for entry of coxsackievirus and adenovirus into cells have been suggested. We have found that tear fluid promotes adenovirus infection, and we have identified human lactoferrin (HLf) as the tear fluid component responsible for this effect. HLf alone was found to promote binding of adenovirus to epithelial cells in a dose-dependent manner and also infection of epithelial cells by adenovirus. HLf was also found to promote gene delivery from an adenovirus-based vector. The mechanism takes place at the binding stage and functions independently of CAR. Thus, we have identified a novel binding mechanism whereby adenovirus hijacks HLf, a component of the innate immune system, and uses it as a bridge for attachment to host cells.
STOCK MECHANICS: A GENERAL THEORY AND METHOD OF ENERGY CONSERVATION WITH APPLICATIONS ON DJIA
Authors: TUNCAY ÇAĞLAR
Published: December 2006

A new method, based on the original theory of conservation of sum of kinetic and potential energy defined for prices is proposed and applied on the Dow Jones Industrials Average (DJIA). The general trends averaged over months or years gave a roughly conserved total energy, with three different potential energies, i.e., positive definite quadratic, negative definite quadratic and linear potential energy for exponential rises (and falls), sinusoidal oscillations and parabolic trajectories, respectively. Corresponding expressions for force (impact) are also given.
SELF-ORGANIZED PATTERNS OF COEXISTENCE OUT OF A PREDATOR-PREY CELLULAR AUTOMATON
Authors: DE CARVALHO KELLY C. , TOMÉ TÂNIA
Published: December 2006

We present a stochastic approach to modeling the dynamics of coexistence of prey and predator populations. It is assumed that the space of coexistence is explicitly subdivided in a grid of cells. Each cell can be occupied by only one individual of each species or can be empty. The system evolves in time according to a probabilistic cellular automaton composed by a set of local rules which describe interactions between species individuals and mimic the process of birth, death and predation. By performing computational simulations, we found that, depending on the values of the parameters of the model, the following states can be reached: a prey absorbing state and active states of two types. In one of them both species coexist in a stationary regime with population densities constant in time. The other kind of active state is characterized by local coupled time oscillations of prey and predator populations. We focus on the self-organized structures arising from spatio-temporal dynamics of the coexistence. We identify distinct spatial patterns of prey and predators and verify that they are intimally connected to the time coexistence behavior of the species.
MOTION REPRESENTATION OF ONE-DIMENSIONAL CELLULAR AUTOMATON RULES
Authors: BOCCARA NINO , FUKŚ HENRYK
Published: December 2006

Generalizing the motion representation we introduced for number-conserving rules, we give a systematic way to construct a generalized motion representation valid for non-conservative rules using the expression of the current, which appears in the discrete version of the continuity equation, completed by the discrete analogue of the source term. This new representation is general, but not unique, and can be used to represent, in a more visual way, any one-dimensional cellular automaton rule. A few illustrative examples are presented.
NEWCOMB-BENFORD LAW IN ASTROPHYSICAL SOURCES
Authors: MORET M. A. , de SENNA V. , PEREIRA M. G. , ZEBENDE G. F.
Published: December 2006

We study the behavior of the numbers in 412 light curves of cataclysmic variables, x-ray binary systems, galaxies, pulsars, supernovae remnants and other x-ray sources present in the public data collected by the instrument All Sky Monitor on board of the satellite Rossi x-ray timing explorer. The temporal light curves were analyzed applying Newcomb-Benford Law. The first digit of the x-ray light curves coming from astrophysical systems obeys the Newcomb-Benford Law as an intrinsic behavior. The nonextensive statistical mechanics behavior of astrophysical sources seem to be the cause for these sources to obey the Newcomb-Benford law. Some x-ray binary systems, however, do not follow this behavior. These systems obey either a gaussian or a bimodal distribution.
POST-STABILIZATION OF INVARIANTS AND APPLICATION TO NUMERICAL ANALYSIS OF CHAOS FOR SOME 3-DIMENSIONAL SYSTEMS
Authors: WU XIN , HE JI ZHOU
Published: December 2006

This research relates to a numerical integrator with post-stabilization of several constraints for an autonomous dynamical system. A generally analytical approach shows that the total energy correction is not valid in most cases, while post-stabilization of each independent energy is. As a typical test example, we consider a non-integrable Hamiltonian system of three degrees of freedom, which can be split into two independent pieces, one 1D harmonic oscillator and another 2D non-integrable system, by using a transformation of variables. Phase portraits on Poincaré sections about the 2D system manifest that our analysis is reasonable. In addition, a problem how to compute Lyapunov exponents in constrained systems is proposed. As a suggestion, it is best to stabilize all constraints involving each energy integral and its corresponding variation in order to avoid spurious Lyapunov exponents. Because an appropriately larger time step is acceptable in this sense, it is not expensive to use the fast Lyapunov indicators to describe the global dynamics of phase space for the 3D system, where regions of chaos and order are clearly identified.
INFECTION MODEL BASED ON HAMMING DISTANCE WITH AGE
Authors: PAN QIU-HUI , LI YU-XING , HE MING-FENG , MU XIAO-JIA
Published: December 2006

In this paper, the individual is represented by a Bit-String based on the Penna model. The infection information is also denoted by a Bit-String including 0 and 1. The degree of getting an infection is rested with the matching degree between the Bit-String of the individual and the Bit-String of infection information. Thus, we define the Hamming Distance with age. The infection rules among individuals is described by Cellular Automata on the lattice with L * L. We discuss the existence and extinction for a certain infection on the process of evolution.
FORCES ON A THREE-LEVEL ATOM INDUCED BY TWO LASER BEAMS
Authors: PARANJAPE V. V. , PANAT P. V.
Published: December 2006

We present formulation of optical forces acting on a three-level atom coupled to two coherent light beams. Analytical expressions for the force are obtained by using the master equation. All three configurations: Raman, V-shaped and cascade are used for the analysis. The dipolar force is obtained numerically as a function of detuning.
NORMALIZED INTENSITY VARIANCE OF A SINGLE-MODE LASER DRIVEN BY QUADRATIC PUMP NOISE
Authors: CAO LI , WU DA-JIN
Published: December 2006

A single-mode laser noise model driven by quadratic pump noise is proposed. The approximation Fokker–Planck equation (AFPE) and steady probability distribution of the laser intensity for the model are derived. It is found that the AFPE is symmetrical with respect to the sign of λ. This point leads to some symmetrical features for the statistical properties of the system. As an important application of the above-mentioned results, the normalized intensity variance NIV is derived. It is found that the NIV is controlled intensively by the cross-correlation between the real and imaginary parts of pump noise. For the NIV versus a curves an interest cross-correlation effect, the two directions of the NIV versus a curves, is found.
NEURAL-ASSOCIATION OF MICROCALCIFICATION PATTERNS FOR THEIR RELIABLE CLASSIFICATION IN DIGITAL MAMMOGRAPHY
Authors: PANCHAL RINKU , VERMA BRIJESH
Published: December 2006

Breast cancer continues to be the most common cause of cancer deaths in women. Early detection of breast cancer is significant for better prognosis. Digital Mammography currently offers the best control strategy for the early detection of breast cancer. The research work in this paper investigates the significance of neural-association of microcalcification patterns for their reliable classification in digital mammograms. The proposed technique explores the auto-associative abilities of a neural network approach to regenerate the composite of its learned patterns most consistent with the new information, thus the regenerated patterns can uniquely signify each input class and improve the overall classification. Two types of features: computer extracted (gray level based statistical) features and human extracted (radiologists' interpretation) features are used for the classification of calcification type of breast abnormalities. The proposed technique attained the highest 90.5% classification rate on the calcification testing dataset.
THE SEMIGROUP OF CONJUGATES OF A WORD
Authors: HIGGINS PETER M.
Published: December 2006

We introduce a finite semigroup associated with a conjugacy class of a word in the free monoid over a finite alphabet. Using properties of this semigroup we derive results on combinatorics on words.
GROWTH SERIES FOR ARTIN GROUPS OF DIHEDRAL TYPE
Authors: MAIRESSE JEAN , MATHÉUS FRÉDÉRIC
Published: December 2006

We consider the Artin groups of dihedral type I2(k) defined by the presentation Ak = 〈a,b | prod (a,b;k) = prod (b,a;k)〉 where prod (s,t;k) = ststs …, with k terms in the product on the right-hand side. We prove that the spherical growth series and the geodesic growth series of Ak with respect to the Artin generators {a,b,a-1, b-1} are rational. We provide explicit formulas for the series.
SOLVABILITY OF EQUATIONS IN GRAPH GROUPS IS DECIDABLE
Authors: DIEKERT VOLKER , MUSCHOLL ANCA
Published: December 2006

We show that the existential theory of free partially commutative monoids with involution is decidable. As a consequence the existential theory of graph groups is also decidable. If the underlying alphabet of generators is fixed, we obtain a PSPACE-completeness result, otherwise (in the uniform setting) our decision procedure is in EXPSPACE. Our proof is a reduction to the main result of [6].
CELLULAR AUTOMATA OVER SEMI-DIRECT PRODUCT GROUPS: REDUCTION AND INVERTIBILITY RESULTS
Authors: CAPOBIANCO SILVIO
Published: December 2006

Cellular automata are transformations of configuration spaces over finitely generated groups, such that the next state in a point only depends on the current state of a finite neighborhood of the point itself. Many questions arise about retrieving global properties from such local descriptions, and finding algorithms to perform these tasks.

We consider the case when the group is a semi-direct product of two finitely generated groups, and show that a finite factor (whatever it is) can be thought of as part of the alphabet instead of the group, preserving both the dynamics and some "finiteness" properties. We also show that, under reasonable hypotheses, this reduction is computable: this leads to some reduction theorems related to the invertibility problem.
PARABOLIC MONOIDS I: STRUCTURE
Authors: PUTCHA MOHAN S.
Published: December 2006

We determine the closure of a parabolic subgroup of a reductive group in a reductive monoid. This allows us to define parabolic submonoids of a finite monoid of Lie type. These are analogues of the monoid of block upper triangular matrices. We determine the structure of [Formula: see text]-class of a finite parabolic monoid and show that such a monoid is generated by its unit group and diagonal idempotents.
IDENTITIES IN THE ALGEBRA OF PARTIAL MAPS
Authors: JACKSON MARCEL , STOKES TIM
Published: December 2006

We consider the identities of a variety of semigroup-related algebras modelling the algebra of partial maps. We show that the identities are intimately related to a weak semigroup deductive system and we show that the equational theory is decidable. We do this by giving a term rewriting system for the variety. We then show that this variety has many subvarieties whose equational theory interprets the full uniform word problem for semigroups and consequently are undecidable. As a corollary it is shown that the equational theory of Clifford semigroups whose natural order is a semilattice is undecidable.
LOCALLY INVARIANT ORDERS ON GROUPS
Authors: CHISWELL I. M.
Published: December 2006

Recent work by T. Delzant and S. Hair shows that certain groups are unique product groups. In effect, they show that the groups have a locally invariant order, an idea introduced by D. Promislow in the early eighties. Having a locally invariant order implies the group is a unique product group, and a strict left (or right) ordering on a group is a locally invariant order. We study properties of the class of LIO groups, that is, groups having a locally invariant order. The main result gives conditions under which the fundamental group of a graph of LIO groups is LIO. In particular, the free product of two LIO groups is LIO. There is an analogous result for a graph of right orderable groups. We also study tree-free groups (those having a free action without inversions on a Λ-tree, for some ordered abelian group Λ). In particular, a detailed proof that tree-free groups are LIO is given. There is also a detailed proof of an observation made by Hair, that the fundamental group of a compact hyperbolic manifold is virtually LIO.
Bezafibrate regulates the expression and enzyme activity of 11β-hydroxysteroid dehydrogenase type 1 in murine adipose tissue and 3T3-L1 adipocytes
Authors: Nakano Shigeru , Inada Yoichi , Masuzaki Hiroaki , Tanaka Tomohiro , Yasue Shintaro , Ishii Takako , Arai Naoki , Ebihara Ken , Hosoda Kiminori , Maruyama Kazuyasu , Yamazaki Yoshinobu , Shibata Nobuo , Nakao Kazuwa
Published: December 2006

A clinically employed antihyperlipidemic drug, bezafibrate, has been characterized as a PPAR(α, -γ, and -δ) pan-agonist in vitro. Recent extended trials have highlighted its antidiabetic properties in humans. However, the underlying molecular mechanism is not fully elucidated. The present study was designed to explore potential regulatory mechanisms of intracellular glucocorticoid reactivating enzyme, 11β-HSD1 and anti-diabetic hormone, adiponectin by bezafibrate in murine adipose tissue, and cultured adipocytes. Treatment of db/db mice with bezafibrate significantly ameliorated hyperglycemia and insulin resistance, accompanied by a marked reduction of triglyceride and nonesterified fatty acids. Despite equipotent in lipid-lowering effects, another fibrate, fenofibrate, did not show such beneficial effects on glycemic control. Treatment of bezafibrate caused a marked decrease in the mRNA level of 11β-HSD1 preferentially in adipose tissue of db/db mice (−47%, P < 0.05), concomitant with a significant increase in plasma adiponectin level (+37%, P < 0.01). Notably, treatment of bezafibrate caused a marked decrease in the mRNA level (−34%, P < 0.01) and enzyme activity (−32%, P < 0.01) of 11β-HSD1, whereas the treatment substantially augmented the expression (+71%, P < 0.01) and secretion (+27%, P < 0.01) of adiponectin in 3T3-L1 adipocytes. Knockdown of 11β-HSD1 by siRNA confirmed that 11β-HSD1 acts as a distinct oxoreductase in adipocytes and validated the enzyme activity assays in the present study. Effects of bezafibrate on regulation of 11β-HSD1 and adiponectin in murine adipocytes were comparable with those in thiazolidinediones. This is the first demonstration that bezafibrate directly regulates 11β-HSD1 and adiponectin in murine adipocytes, both of which may contribute to metabolically-beneficial effects by bezafibrate.
A deficient TLR2 signaling promotes airway mucin production inMycoplasma pneumoniae-infected allergic mice
Authors: Wu Qun , Martin Richard J. , Rino John G. , Jeyaseelan Samithamby , Breed Rachel , Chu Hong Wei
Published: December 2006

The original hygiene hypothesis suggests that early childhood respiratory infections preceding allergen exposure may decrease the prevalence of allergic diseases. We have recently demonstrated that Mycoplasma pneumoniae infection preceding allergen exposure reduced allergic responses in mice. However, the molecular mechanisms underlying the protective role of M. pneumoniae in allergic responses, particularly airway mucin production, remain unclear. Wild-type and Toll-like receptor 2 (TLR2)-deficient mice with a respiratory M. pneumoniae infection preceding allergen (ovalbumin) challenge were utilized to determine the regulatory role of TLR2-IFN-γ signaling pathway in airway mucin expression. Furthermore, air-liquid interface cultures of mouse primary tracheal epithelial cells were performed to examine the effects of IFN-γ on mucin expression. In wild-type mice, M. pneumoniae infection preceding allergen challenge significantly reduced airway mucins but increased IFN-γ. In sharp contrast, in TLR2-deficient mice, M. pneumoniae preceding allergen challenge resulted in increased mucin protein without a noticeable change of IFN-γ. In cultured mouse primary tracheal epithelial cells, IFN-γ was shown to directly inhibit mucin expression in a dose-dependent manner. Our study demonstrates for the first time that a respiratory M. pneumoniae infection preceding allergen challenge reduces airway epithelial mucin expression in part through TLR2-IFN-γ signaling pathway. A bacterial infection in asthmatic subjects with weakened TLR2-IFN-γ signaling may result in an exaggerated airway mucin production.
Renin receptor expression in human adipose tissue
Authors: Achard Vincent , Boullu-Ciocca Sandrine , Desbriere Raoul , Nguyen Geneviève , Grino Michel
Published: December 2006

Adipose tissue synthesizes all components of the renin-angiotensin system. The renin receptor (RenR) is able, on renin binding, to increase its efficiency to generate angiotensin I from angiotensinogen. We demonstrate that RenR is specifically synthesized in the stromal portion of human adipose tissue in both isolated interadipocyte stromal cells and in stromal areas. RenR is expressed at the periphery of cells, strongly suggesting a membranal localization. RenR protein expression in primary cultures of human stromal cells decreased significantly during differentiation, whereas RenR mRNA levels did not change, demonstrating that RenR was expressed in both preadipocyte and nonpreadipocyte cells, and was regulated at a posttranscriptional level. Double-labeling immunohistochemistry of human adipose tissue sections revealed that RenR was colocalized with renin, whereas incubation of 3T3-L1, a preadipocyte cell line, with renin stimulated the phosphorylation state of the intracellular signaling pathway ERK 1/2, and short exposure of human adipose stromal cells in primary culture to renin was followed by a long-lasting dose-dependent increase of angiotensin I generation, indicating that adipose RenR is functional. We show, using a large set of human adipose tissue biopsies, that RenR expression was increased in visceral compared with subcutaneous adipose tissue of lean and obese patients. Taken together with our finding that RenR was colocalized with plasminogen activator inhibitor type 1, the main inhibitor of the fibrinolytic system in visceral adipose tissue, the above-mentioned data suggest that RenR plays a role in obesity-induced visceral adipose tissue accumulation and its accompanying cardiovascular complications.
Hypothalamic expression of thyroid hormone-activating and -inactivating enzyme genes in relation to photorefractoriness in birds and mammals
Authors: Watanabe Tsuyoshi , Yamamura Takashi , Watanabe Miwa , Yasuo Shinobu , Nakao Nobuhiro , Dawson Alistair , Ebihara Shizufumi , Yoshimura Takashi
Published: December 2006

Photorefractoriness is the insensitivity of gonadal development to the stimulatory effects of long photoperiods in birds and to the inhibitory effects of short photoperiods in small mammals. Its molecular mechanism remains unknown. Recently, it has been shown that reciprocal expression of thyroid hormone-activating enzyme [type 2 deiodinase (Dio2)] and -inactivating enzyme [type 3 deiodinase (Dio3)] genes in the mediobasal hypothalamus is critical for photoperiodically induced gonadal growth. Since thyroid hormones are required not only for photoinduction, but also for the induction of photorefractoriness, we examined the expression of these genes in relation to photorefractoriness in birds and mammals. Transfer of birds to long photoperiods induced strong expression of Dio2. This was maintained in tree sparrow when they later became photorefractory, but decreased somewhat in quail. In hamsters, transfer to long photoperiods also induced strong expression of Dio2. High values were not maintained under long photoperiods, and, indeed, expression decreased at the same rate as in animals transferred to short photoperiods. There was no renewed expression of Dio2 associated with testicular growth as animals became refractory to short photoperiods. Expression of Dio3 was high under short photoperiods and low under long photoperiods in all the animals examined, except for the short photoperiod-refractory hamsters. Our present study revealed complex regulation of deiodinase genes in the photoinduction and photorefractory processes in birds and mammals. These gene changes may be involved in the regulation of photorefractoriness, as well as photoinduction.