bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Mutations in the Human Immunoglobulin A1 (IgA1) Hinge on Its Susceptibility to Cleavage by Diverse Bacterial IgA1 Proteases
Authors: Senior Bernard W. , Woof Jenny M.
Published: February 2005

Components of the human immunoglobulin A1 (IgA1) hinge governing sensitivity to cleavage by bacterial IgA1 proteases were investigated. Recombinant antibodies with distinct hinge mutations were constructed from a hybrid comprised of human IgA2 bearing half of the human IgA1 hinge region. This hybrid antibody and all the mutant antibodies derived from it were resistant to cleavage by the IgA1 proteases fromStreptococcus oralisandStreptococcus mitisbiovar 1 strains but were cleaved to various degrees by those ofStreptococcus pneumoniae, someStreptococcus sanguisstrains, and the type 1 and 2 IgA1 proteases ofHaemophilus influenzae,Neisseria meningitidis, andNeisseria gonorrhoeae. Remarkably, those proteases that cleave a Pro-Ser peptide bond in the wild-type IgA1 hinge were able to cleave mutant antibodies lacking a Pro-Ser peptide bond in the hinge, and those that cleave a Pro-Thr peptide bond in the wild-type IgA1 hinge were able to cleave mutant antibodies devoid of a Pro-Thr peptide bond in the hinge. Thus, the enzymes can cleave alternatives to their preferred postproline peptide bond when such a bond is unavailable. Peptide sequence analysis of a representative antibody digestion product confirmed this conclusion. The presence of a cleavable peptide bond near the CH2 end of the hinge appeared to result in greater cleavage than if the scissile bond was at the CH1 end of the hinge. Proline-to-serine substitution at residue 230 in a hinge containing potentially cleavable Pro-Ser and Pro-Thr peptide bonds increased the resistance of the antibody to cleavage by many IgA1 proteases.
Gingipains fromPorphyromonas gingivalisW83 Induce Cell Adhesion Molecule Cleavage and Apoptosis in Endothelial Cells
Authors: Sheets Shaun M. , Potempa Jan , Travis James , Casiano Carlos A. , Fletcher Hansel M.
Published: February 2005

The presence ofPorphyromonas gingivalisin the periodontal pocket and the high levels of gingipain activity detected in gingival crevicular fluid could implicate a role for gingipains in the destruction of the highly vascular periodontal tissue. To explore the effects of these proteases on endothelial cells, we exposed bovine coronary artery endothelial cells and human microvascular endothelial cells to gingipain-active extracellular protein preparations and/or purified gingipains fromP. gingivalis. Treated cells exhibited a rapid loss of cell adhesion properties that was followed by apoptotic cell death. Cleavage of N- and VE-cadherin and integrin β1 was observed in immunoblots of cell lysates. There was a direct correlation between the kinetics of cleavage of N- and VE-cadherin and loss of cell adhesion properties. Loss of cell adhesion, as well as N- and VE-cadherin and integrin β1 cleavage, could be inhibited or significantly delayed by preincubation ofP. gingivalisW83 gingipain-active extracellular extracts with the cysteine protease inhibitorNα-p-tosyl-l-lysine chloromethylketone. Furthermore, purified gingipains also induced endothelial cell detachment and apoptosis. Apoptosis-associated events, including annexin V positivity, caspase-3 activation, and cleavage of the caspase substrates poly(ADP-ribose) polymerase and topoisomerase I (Topo I), were observed in endothelial cells after detachment. All of the effects observed were correlated with the different levels of cysteine-dependent proteolytic activity of the extracts tested. Taken together, these results indicate that gingipains fromP. gingivaliscan alter cell adhesion molecules and induce endothelial cell death, which could have implications for the pathogenicity of this organism.
A Live and InactivatedChlamydia trachomatisMouse Pneumonitis Strain Induces the Maturation of Dendritic Cells That Are Phenotypically and Immunologically Distinct
Authors: Rey-Ladino Jose , Koochesfahani Kasra M. , Zaharik Michelle L. , Shen Caixia , Brunham Robert C.
Published: February 2005

The intracellular bacterial pathogenChlamydia trachomatisis a major cause of sexually transmitted disease worldwide. While protective immunity does appear to develop following natural chlamydial infection in humans, early vaccine trials using heat-killedC. trachomatisresulted in limited and transient protection with possible enhanced disease during follow-up. Thus, immunity following natural infection with live chlamydia may differ from immune responses induced by immunization with inactivated chlamydia. To study this differing immunology, we used murine bone marrow-derived dendritic cells (DC) to examine DC maturation and immune effector function induced by live and UV-irradiatedC. trachomatiselementary bodies (live EBs and UV-EB, respectively). DC exposed to live EBs acquired a mature DC morphology; expressed high levels of major histocompatibility complex (MHC) class II, CD80, CD86, CD40, and ICAM-1; produced elevated amounts of interleukin-12 and tumor necrosis factor alpha; and were efficiently recognized byChlamydia-specific CD4+T cells. In contrast, UV-EB-pulsed DC expressed low levels of CD40 and CD86 but displayed high levels of MHC class II, ICAM-1, and CD80; secreted low levels of proinflammatory cytokines; and exhibited reduced recognition byChlamydia-specific CD4+T cells. Adoptive transfer of live EB-pulsed DC was more effective than that of UV-EB-pulsed DC at protecting mice against challenge with liveC. trachomatis. The expression of DC maturation markers and immune protection induced by UV-EB could be significantly enhanced by costimulation of DC ex vivo with UV-EB and oligodeoxynucleotides containing cytosine phosphate guanosine; however, the level of protection was significantly less than that achieved by using DC pulsed ex vivo with viable EBs. Thus, exposure of DC to live EBs results in a mature DC phenotype which is able to promote protective immunity, while exposure to UV-EB generates a semimature DC phenotype with less protective potential. This result may explain in part the differences in protective immunity induced by natural infection and immunization with whole inactivated organisms and is relevant to rational chlamydia vaccine design strategies.
ThePseudomonas aeruginosaQuorum-Sensing MoleculeN-3-(Oxododecanoyl)-l-Homoserine Lactone Inhibits T-Cell Differentiation and Cytokine Production by a Mechanism Involving an Early Step in T-Cell Activation
Authors: Ritchie A. J. , Jansson A. , Stallberg J. , Nilsson P. , Lysaght P. , Cooley M. A.
Published: February 2005

ThePseudomonas aeruginosaquorum-sensing moleculeN-3-(oxododecanoyl)-l-homoserine lactone (OdDHL) has been reported to have immunomodulatory activity in several systems, although the mechanism of that activity remains to be fully characterized. We demonstrate here, using a defined in vitro model of antigen responses by T-cell receptor (TCR)-transgenic mouse splenic CD4 T cells, that the effect of OdDHL on activation and cytokine production is complete within 4 h of antigen or mitogen stimulation and does not depend on the insertion of OdDHL in the cell membrane, despite a previous report that immunosuppression by homoserine lactones required a minimum acyl chain length of 11 carbons (S. R. Chhabra, C. Harty, D. S. W. Hooi, M. Daykin, B. W. Bycroft, P. Williams, and D. Pritchard, J. Med. Chem.46:97-104, 2003). We also demonstrate that while OdDHL can have toxic effects on nonlymphoid leukocytes, it does not induce significant cell death in T cells at the concentrations (≤10 μM) used in these experiments. In addition, we show that primary and secondary antigen-specific cytokine responses are equally susceptible to inhibition by OdDHL and that the compound inhibits the differentiation of both Th1 and Th2 cells. However, the precise balance of cytokine production by CD4 T cells stimulated in the presence of OdDHL varies with both the antigen concentration and its affinity for the transgenic TCR. Thus, conflicting reports of the nature of the immunosuppression by OdDHL may be due in part to the differences in antigen affinity and concentration in different models.
Roles of Cell Adhesion and Cytoskeleton Activity in
Entamoeba histolytica
Pathogenesis: a Delicate Balance
Authors: Tavares Paulo , Rigothier Marie-Christine , Khun Huot , Roux Pascal , Huerre Michel , Guillén Nancy
Published: February 2005

The protozoan parasite
Entamoeba histolytica
colonizes the human large bowel. Invasion of the intestinal epithelium causes amoebic colitis and opens the route for amoebic liver abscesses. The parasite relies on its dynamic actomyosin cytoskeleton and on surface adhesion molecules for dissemination in the human tissues. Here we show that the galactose/
N
-acetylgalactosamine (Gal/GalNAc) lectin clusters in focal structures localized in the region of
E. histolytica
that contacts monolayers of enterocytes. Disruption of myosin II activity impairs the formation of these structures and renders the trophozoites avirulent for liver abscess development. Production of the cytoplasmic domain of the
E. histolytica
Gal/GalNAc lectin in engineered trophozoites causes reduced adhesion to enterocytes. Intraportal delivery of these parasites to the liver leads to the formation of a large number of small abscesses with disorganized morphology that are localized in the vicinity of blood vessels. The data support a model for invasion in which parasite motility is essential for establishment of infectious foci, while the adhesion to host cells modulates the distribution of trophozoites in the liver and their capacity to migrate in the hepatic tissue.
Selection of Resistance in Protease Inhibitor-Experienced, Human Immunodeficiency Virus Type 1-Infected Subjects Failing Lopinavir- and Ritonavir-Based Therapy: Mutation Patterns and Baseline Correlates
Authors: Mo Hongmei , King Martin S. , King Kathryn , Molla Akhteruzzaman , Brun Scott , Kempf Dale J.
Published: February 2005

The selection of in vivo resistance to lopinavir was characterized by analyzing the longitudinal isolates from 54 protease inhibitor-experienced subjects who either experienced incomplete virologic response or viral rebound subsequent to initial response while on treatment with lopinavir-ritonavir in Phase II and III studies. The evolution of incremental resistance to lopinavir (emergence of new mutation[s] and/or at least a twofold increase in phenotypic resistance compared to baseline isolates) was highly dependent on the baseline phenotype and genotype. Among the subjects demonstrating evolution of lopinavir resistance, mutations at positions 82, 54, and 46 in human immunodeficiency virus protease emerged frequently, suggesting that these mutations are important for conferring high-level resistance. Less common mutations, such as L33F, I50V, and V32I together with I47V/A, were also selected; however, new mutations at positions 84, 90, and 71 were not observed. The emergence of incremental resistance contrasts greatly with the low incidence of resistance observed after initiating lopinavir-ritonavir therapy in antiretroviral-naive patients, suggesting that partial resistance accumulated during prior protease inhibitor therapy can compromise the genetic barrier to resistance to lopinavir-ritonavir. The emergence of incremental resistance was uncommon in subjects whose baseline isolates contained eight or more mutations associated with lopinavir resistance and/or displayed >60-fold-reduced susceptibility to lopinavir, providing insight into suitable upper genotypic and phenotypic breakpoints for lopinavir-ritonavir.
Increased Epitope-Specific CD8+T Cells Prevent Murine Coronavirus Spread to the Spinal Cord and Subsequent Demyelination
Authors: MacNamara Katherine C. , Chua Ming Ming , Nelson Peter T. , Shen Hao , Weiss Susan R.
Published: February 2005

CD8+T cells are important for clearance of neurotropic mouse hepatitis virus (MHV) strain A59, although their possible role in A59-induced demyelination is not well understood. We developed an adoptive-transfer model to more clearly elucidate the role of virus-specific CD8+T cells during the acute and chronic phases of infection with A59 that is described as follows. C57BL/6 mice were infected with a recombinant A59 virus expressing the gp33 epitope, an H-2Db-restricted CD8+T-cell epitope encoded in the glycoprotein of lymphocytic choriomeningitis virus, as a fusion with the enhanced green fluorescent protein (RA59-gfp/gp33). P14 splenocytes (transgenic for a T-cell receptor specific for the gp33 epitope) were transferred at different times pre- and postinfection (p.i.). Adoptive transfer of P14 splenocytes 1 day prior to infection with RA59-gfp/gp33, but not control virus lacking the gp33 epitope, RA59-gfp, reduced weight loss and viral replication and spread in the brain and to the spinal cord. Furthermore, demyelination was significantly reduced compared to that in nonrecipients. However, when P14 cells were transferred on day 3 or 5 p.i., no difference in acute or chronic disease was observed compared to that in nonrecipients. Protection in mice receiving P14 splenocytes prior to infection correlated with a robust gp33-specific immune response that was not observed in mice receiving the later transfers. Thus, an early robust CD8+T-cell response was necessary to reduce virus replication and spread, specifically to the spinal cord, which protected against demyelination in the chronic phase of the disease.
Nuclear Localization of Japanese Encephalitis Virus Core Protein Enhances Viral Replication
Authors: Mori Yoshio , Okabayashi Tamaki , Yamashita Tetsuo , Zhao Zijiang , Wakita Takaji , Yasui Kotaro , Hasebe Futoshi , Tadano Masayuki , Konishi Eiji , Moriishi Kohji , Matsuura Yoshiharu
Published: February 2005

Japanese encephalitis virus (JEV) core protein was detected in both the nucleoli and cytoplasm of mammalian and insect cell lines infected with JEV or transfected with the expression plasmid of the core protein. Mutation analysis revealed that Gly
42
and Pro
43
in the core protein are essential for the nuclear and nucleolar localization. A mutant M4243 virus in which both Gly
42
and Pro
43
were replaced by Ala was recovered by plasmid-based reverse genetics. In C6/36 mosquito cells, the M4243 virus exhibited RNA replication and protein synthesis comparable to wild-type JEV, whereas propagation in Vero cells was impaired. The mutant core protein was detected in the cytoplasm but not in the nucleus of either C6/36 or Vero cell lines infected with the M4243 virus. The impaired propagation of M4243 in mammalian cells was recovered by the expression of wild-type core protein in
trans
but not by that of the mutant core protein. Although M4243 mutant virus exhibited a high level of neurovirulence comparable to wild-type JEV in spite of the approximately 100-fold-lower viral propagation after intracerebral inoculation to 3-week-old mice of strain Jcl:ICR, no virus was recovered from the brain after intraperitoneal inoculation of the mutant. These results indicate that nuclear localization of JEV core protein plays crucial roles not only in the replication in mammalian cells in vitro but also in the pathogenesis of encephalitis induced by JEV in vivo.
Importin-α Promotes Passage through the Nuclear Pore Complex of Human Immunodeficiency Virus Type 1 Vpr
Authors: Kamata Masakazu , Nitahara-Kasahara Yuko , Miyamoto Yoichi , Yoneda Yoshihiro , Aida Yoko
Published: February 2005

Viral protein R (Vpr) of human immunodeficiency virus type 1 has potent karyophilic properties, but details of the mechanism by which it enters the nucleus remain to be clarified. We reported previously that two regions, located between residues 17 and 34 (αH1) and between residues 46 and 74 (αH2), are indispensable for the nuclear localization of Vpr. Here, we reveal that a chimeric protein composed of the nuclear localization signal of Vpr, glutathione
S
-transferase, and green fluorescent protein was localized at the nuclear envelope and then entered the nucleus upon addition of importin-α. An in vitro transport assay using a series of derivatives of importin-α demonstrated that the carboxyl terminus was required for this nuclear import process. We also showed that Vpr interacts with importin-α through αH1 and αH2; only the interaction via αH1 is indispensable for the nuclear entry of Vpr. These observations indicate that importin-α functions as a mediator for the nuclear entry of Vpr.
Role of the Conserved Nucleotide Mismatch within 3′- and 5′-Terminal Regions of Bunyamwera Virus in Signaling Transcription
Authors: Barr John N. , Wertz Gail W.
Published: February 2005

Bunyamwera virus
(BUNV) is the prototype of the
Bunyaviridae
family of tri-partite negative-sense RNA viruses. The three BUNV segments possess 3′ and 5′ nontranslated regions (NTRs) that signal two RNA synthesis activities: (i) transcription to generate mRNAs and (ii) replication to generate antigenomes that are replicated to yield further genomes. While the genome acts as a template for synthesis of both transcription and replication products, the antigenome allows synthesis of only replication products, with mRNAs being undetectable. Here, we investigate the basis for the fundamentally different signaling abilities of genomic and antigenomic strands. We show that the identity of only nucleotide position 9 within the genomic 3′ NTR is critical for the different RNA synthesis characteristics of genomic and antigenomic strands, thus identifying this nucleotide as an essential component of the transcription promoter. This nucleotide is distinctive, as it interrupts an unbroken run of conserved complementary nucleotides within the 3′ and 5′ NTRs of all three segments. Our results show that the conserved mismatched arrangement of this nucleotide plays no detectable role in signaling transcription. Instead, we show that the transcription-signaling ability of this position is entirely dependent on its nucleotide identity. We further show that while a U residue at 3′ position 9 is strongly preferred for transcription activity in the context of the genomic promoter, it does not signal transcription in the context of the antigenomic promoter. Therefore, our results show that the identity of 3′ position 9 is crucial for signaling BUNV transcription; however, it is not the sole determinant.
BFRF1 of Epstein-Barr Virus Is Essential for Efficient Primary Viral Envelopment and Egress
Authors: Farina Antonella , Feederle Regina , Raffa Salvatore , Gonnella Roberta , Santarelli Roberta , Frati Luigi , Angeloni Antonio , Torrisi Maria Rosaria , Faggioni Alberto , Delecluse Henri-Jacques
Published: February 2005

The molecular mechanisms that underlie maturation and egress of Epstein-Barr virus (EBV) virions are only partially characterized. We have recently shown that the BFRF1 gene, the EBV positional homolog of herpes simplex virus type 1 and pseudorabies virus UL34, is expressed early during EBV lytic replication and that it is found predominantly on the nuclear membrane (A. Farina, R. Santarelli, R. Gonnella, R. Bei, R. Muraro, G. Cardinali, S. Uccini, G. Ragona, L. Frati, A. Faggioni, and A. Angeloni, J. Virol. 74:3235-3244, 2000). These data suggest that the BFRF1 protein might be involved in viral primary envelopment. To precisely determine the function of this protein, we have constructed an EBV mutant devoid of the BFRF1 gene (BFRF1-KO). 293 cells carrying BFRF1-KO showed no differences in comparison with wild-type EBV in terms of DNA lytic replication or expression of late viral proteins upon induction of the lytic cycle. However, binding assays and infection experiments using cell lines or human cord blood lymphocytes showed a clear reduction in the viral mutant titers. Complementation experiments with BFRF1-KO and a BFRF1 expression vector restored viral titers to levels similar to those for the wild-type control, showing that the modifications that we introduced were limited to the BFRF1 gene. Electron microscopic observations showed that the reduction in viral titers was due to sequestration of EBV nucleocapsids in the nuclei of lytically induced cells. This suggests that BFRF1 is involved in transport of the maturing virion across the nuclear membrane. This hypothesis was further supported by the observation that BFRF1 is present in maturing intracellular virions but not in their extracellular counterparts. This implies that BFRF1 is a key protein for EBV maturation.
The Global Transcriptional Effects of the Human Papillomavirus E6 Protein in Cervical Carcinoma Cell Lines Are Mediated by the E6AP Ubiquitin Ligase
Authors: Kelley Melissa L. , Keiger Kerri E. , Lee Chan Jae , Huibregtse Jon M.
Published: February 2005

The function of the human papillomavirus (HPV) E6 protein that is most clearly linked to carcinogenesis is the targeted degradation of p53, which is dependent on the E6AP ubiquitin ligase. Additional functions have been attributed to E6, including the stimulation of telomerase activity and the targeted degradation of other cellular proteins, but in most cases it is unclear whether these activities are also E6AP dependent. While E6 clearly influences the transcriptional program of HPV-positive cell lines through the inactivation of p53, it has been shown that at least a subset of its p53-independent functions are also reflected in the transcriptional program. For this study, we have determined the extent to which E6AP is involved in mediating the set of E6 functions that impact on the global transcriptional program of HPV-positive cell lines. The transcriptional profiles of ∼31,000 genes were characterized for three cell lines (HeLa, Caski, and SiHa cells) after small interfering RNA (siRNA)-mediated silencing of E6 or E6AP. We found that E6 and E6AP siRNAs elicited nearly identical alterations in the transcriptional profile of each cell line. Some of the expression alterations were apparent secondary effects of p53 stabilization, while the basis of most other changes was not reconcilable with previously proposed E6 functions. While expression changes of the TERT gene (telomerase catalytic subunit) were not revealed by the array, telomerase repeat amplification protocol assays showed that both E6 and E6AP knockouts resulted in a suppression of telomerase activity. Together, these results suggest that E6AP mediates a broad spectrum of E6 functions, including virtually all functions that impact on the transcriptional program of HPV-positive cell lines.
Enhanced Cellular Immunity in Macaques following a Novel Peptide Immunotherapy
Authors: Chea S. , Dale C. J. , De Rose R. , Ramshaw I. A. , Kent S. J.
Published: February 2005

Advances in treating and preventing AIDS depend on understanding how human immunodeficiency virus (HIV) is eliminated in vivo and on the manipulation of effective immune responses to HIV. During the development of assays quantifying the elimination of fluorescent autologous cells coated with overlapping 15-mer simian immunodeficiency virus (SIV) or HIV-1 peptides, we made a remarkable observation: the reinfusion of macaque peripheral blood mononuclear cells, or even whole blood, pulsed with SIV and/or HIV peptides generated sharply enhanced SIV- and HIV-1-specific T-cell immunity. Strong, broad CD4+- and CD8+-T-cell responses could be enhanced simultaneously against peptide pools spanning 87% of all SIV- and HIV-1-expressed proteins—highly desirable characteristics of HIV-specific immunity. De novo hepatitis C virus-specific CD4+- and CD8+-T-cell responses were generated in macaques by the same method. This simple technique holds promise for the immunotherapy of HIV and other chronic viral infections.
The C-Terminal Half of TSG101 Blocks Rous Sarcoma Virus Budding and Sequesters Gag into Unique Nonendosomal Structures
Authors: Johnson Marc C. , Spidel Jared L. , Ako-Adjei Danso , Wills John W. , Vogt Volker M.
Published: February 2005

Retroviral late domains (L domains) are short amino acid sequences in the Gag protein that facilitate the process of budding. L domains act by recruiting the ESCRT complexes, which normally function in the formation of multivesicular bodies. The PTAP late domain of human immunodeficiency virus (HIV) is believed to specifically recruit this machinery by binding the ESCRT protein TSG101. It was recently demonstrated that expression of a C-terminal fragment of TSG101 (TSG-3′) blocked the budding of both PTAP-dependent and PPPY-dependent retroviruses. We show here that TSG-3′ expression leads to the formation of large spherical entities that we call TICS (TSG-3′-induced cellular structures) in the cytoplasm. Rous sarcoma virus (RSV) and murine leukemia virus (MLV) Gag proteins are selectively recruited to these structures, but HIV type 1 Gag is completely excluded. Experiments with various HIV and RSV vector constructs as well as HIV and RSV chimeras suggest that recruitment to the TICS is late domain independent and does not involve recognition of any single amino acid sequence. TICS appear to have no limiting membrane and do not colocalize with markers for any membranous cellular compartment. Wild-type TSG101 is also recruited to TICS, but most other ESCRT proteins are excluded. These structures are similar in nature to aggresomes, colocalize with the aggresome marker GFP-250, and are highly enriched in ubiquitin but in other ways do not fully meet the description of aggresomes. We conclude that the block to retroviral budding by TSG-3′ may be the result of its sequestration of Gag, depletion of free TSG101, or depletion of free ubiquitin.
Functional Analysis of the Pseudorabies Virus UL51 Protein
Authors: Klupp Barbara G. , Granzow Harald , Klopfleisch Robert , Fuchs Walter , Kopp Martina , Lenk Matthias , Mettenleiter Thomas C.
Published: February 2005

Homologs of the UL51 protein of herpes simplex virus have been identified in all herpesvirus subfamilies, but until now, no function has been assigned to any of them. To investigate function of the UL51 gene product of the alphaherpesvirus pseudorabies virus (PrV), we isolated and analyzed a mutant lacking the major part of the open reading frame, PrV-ΔUL51F, and a rescuant. One-step growth analysis of PrV-ΔUL51F revealed only slightly reduced titers, but plaque size was notably diminished and reached only approximately 30% the plaque size of wild-type PrV. Ultrastructurally, intracytoplasmic capsids were found in large numbers either without envelope or in different stages of envelopment, indicating that secondary envelopment in the cytoplasm was less efficient. However, neuroinvasion in the mouse trigeminal pathway after intranasal infection was only slightly delayed. A PrV UL11 mutant also showed a defect in secondary envelopment (M. Kopp, H. Granzow, W. Fuchs, B. G. Klupp, E. Mundt, A. Karger, and T. C. Mettenleiter, J. Virol. 77:5339-5351, 2003). Since both proteins are part of the viral tegument and are predicted to be membrane associated, they may serve similar, possibly redundant functions during viral morphogenesis. Therefore, we also isolated a mutant simultaneously lacking UL51 and UL11. This mutant exhibited further reduced plaque size compared to the single-deletion mutants, but viral titers were comparable to those for the UL11 mutant. In electron microscopic analyses, the observed defect in secondary envelopment was similar to that found in the UL11 single-deletion mutant. In conclusion, both conserved tegument proteins, either singly or in combination, are involved in virion morphogenesis in the cytoplasm but are not essential for viral replication in vitro and in vivo.
Pairs of Vp1 Cysteine Residues Essential for Simian Virus 40 Infection
Authors: Li Peggy P. , Nakanishi Akira , Fontanes Vanessa , Kasamatsu Harumi
Published: February 2005

Transient disulfide bonding occurs during the intracellular folding and pentamerization of simian virus 40 (SV40) major capsid protein Vp1 (P. P. Li, A. Nakanishi, S. W. Clark, and H. Kasamatsu, Proc. Natl. Acad. Sci. USA
99:
1353-1358, 2002). We investigated the requirement for Vp1 cysteine pairs during SV40 infection. Our analysis identified three Vp1 double-cysteine mutant combinations that abolished viability as assayed by plaque formation. Mutating the Cys49-Cys87 pair or the Cys87-Cys254 pair led to ineffective nuclear localization and diminished accumulation of the mutant Vp1s, and the defect extended in a dominant-negative manner to the wild-type minor capsid proteins Vp2/3 and an affinity-tagged recombinant Vp1 expressed in the same cells. Mutating the Cys87-Cys207 pair preserved the nuclear localization and normal accumulation of the capsid proteins but diminished the production of virus-like particles. Our results are consistent with a role for Cys49, Cys87, and Cys254 in the folding and cytoplasmic-nuclear trafficking of Vp1 and with a role for Cys87 and Cys207 in the assembly of infectious particles. These findings suggest that transient disulfide bond formation between certain Vp1 cysteine residues functions at two stages of SV40 infection: during Vp1 folding and oligomerization in the cytoplasm and during virion assembly in the nucleus.
Human Cytomegalovirus Immediate-Early 2 Gene Expression Blocks Virus-Induced Beta Interferon Production
Authors: Taylor R. Travis , Bresnahan Wade A.
Published: February 2005

The effect of human cytomegalovirus (HCMV) gene expression on beta interferon (IFN-β) expression was examined. We demonstrate that the HCMV immediate-early 2 (IE2) gene product IE86 can effectively block the induction of IFN-β during HCMV infection. IE86 also efficiently blocked the induction of IFN-β following Sendai virus infection, demonstrating that IE86's ability to block induction of IFN-β is not limited to HCMV infection, identifying IE2 as an IFN-β antagonist.
Relation between foot arch index and ankle strength in elite gymnasts: a preliminary study
Authors: Aydog S T , Özçakar L , Tetik O , Demirel H A , Hasçelik Z , Doral M N
Published: February 2005

Background:Gymnasts usually start intensive training from early childhood. The impact of such strenuous training on the musculoskeletal system is not clear.

Objectives:To evaluate the relation between muscle strength of the ankle joint and foot structure in gymnasts.

Methods:The study population comprised 20 high level male gymnasts and 17 non-athletic healthy male controls. Arch indices were measured using a podoscope. Ankle plantar/dorsiflexion and eversion/inversion strengths were measured using a Biodex 3 dynamometer within the protocol of concentric/concentric five repetitions at 30°/s velocity.

Results:The mean arch index of the right and left foot of the gymnasts and the controls were respectively: 31.4 (29.1), 34.01 (34.65); 60.01 (30.3), 63.75 (32.27). Both the arch indices and the ankle dorsiflexion strengths were lower in the gymnasts. Although no correlation was found between strength and arch index in the control group, a significant correlation was observed between eversion strengths and arch indices of the gymnasts (r =  0.41, p  =  0.02).

Conclusions:Whether or not the findings indicate sport specific adaptation or less training of the ankle dorsiflexors, prospective data are required to elucidate the tendency for pes cavus in gymnasts, for whom stabilisation of the foot is a priority.
Does changing the configuration of a motor racing circuit make it safer?
Authors: Leonard L , Lim A , Chesser T J S , Norton S A , Nolan J P
Published: February 2005

Objectives:To assess the pattern of injuries presenting to a racing circuit medical centre in two three-year periods before and after two chicanes were built into the track.

Methods:Medical centre records were used to identify all patients assessed during the two time periods. Those referred to hospital were categorised by injury severity into three groups.

Results:The proportions of those attending the medical centre that were referred and admitted to hospital were the same in both periods (12–13% and 3% respectively). During the two study periods, the risk of a severe injury for a car driver decreased from 0.1% to 0.03% (p<0.05). For a motorcyclist, similar values were 0% and 0.2% (not significant).

Conclusions:Chicanes have improved the safety of the racing circuit for car drivers, reducing the risk of injury.
Effect of sporting activity on absenteeism in a working population
Authors: van den Heuvel S G , Boshuizen H C , Hildebrandt V H , Blatter B M , Ariëns G A , Bongers P M
Published: February 2005

Objectives:To determine the effects of sporting activity on absenteeism in a working population.

Methods:Data were used from a prospective cohort study in a working population with a follow up period of 3 years and were collected with yearly questionnaires or collected from company records. Complete data on absenteeism, sporting activity, and potential confounders were collected for 1228 workers. ANOVA was used to test differences in frequency and duration of absenteeism, correlations were computed to measure the association between number of sporting years (divided by age) and frequency and duration of absenteeism, and survival analysis, according to the Cox proportional hazards model, was used to test differences in relative risk at absenteeism and recovery. All analyses were adjusted for age, gender, smoking, and alcohol consumption, and were stratified for employees with sedentary and with more active jobs.

Results:ANOVA showed a statistically significant higher mean duration of absenteeism among employees not practicing sports, of approximately 20 days over a period of 4 years. The survival analysis showed an increased relative risk at absenteeism (relative risk (RR) 1.09; confidence interval (CI) 1.01 to 1.18) and a decreased relative risk at recovery (RR 0.90; CI 0.85 to 0.95) for employees not practicing sports. The effect of sporting activity is larger in employees with sedentary work. No associations were found between number of sporting years and absenteeism.

Conclusion:Employees practicing sports take sick leave significantly less often than their colleagues not practicing sports, while their periods of sick leave are shorter, especially when their work is sedentary.
EVOLUTION OF RELATIVE SYNONYMOUS CODON USAGE IN HUMAN IMMUNODEFICIENCY VIRUS TYPE-1
Authors: MEINTJES PETER L. , RODRIGO ALLEN G.
Published: February 2005

Mutation in Human Immunodeficiency Virus type-1 (HIV-1) is extremely rapid, a consequence of a low-fidelity viral reverse transcription process. The envelope gene has been shown to accumulate substitutions at a rate of approximately 1% per year and can frequently spend a long time in the host (approximately 10 years). The relative synonymous codon usage (RSCU) in HIV-1 is known to be different from that of the human host. However, by reengineering the protein coding sequences of HIV-1 to reflect the RSCU patterns observed in humans, a large increase in protein expression is observed. It is reasonable to suggest that within a host there may be a selective drive for change in the RSCU of HIV-1 towards human RSCU.

To test this hypothesis we analyzed HIV-1 partial envelope sequences from eight patients sampled serially in time. For each sequence, an RSCU table was constructed. Sequences were labelled as "early" or "late" depending on whether they were sampled before or after the mid-point of the study. Using the RSCU values as descriptor variables, a Principal Components Analysis (PCA) was performed. The first three components clearly discriminated between early and late sequences. We also constructed pooled groupwise RSCU tables for early and late sequences. The viral RSCU values of each of the groups were correlated with human RSCU. If there is selection for host-adaptation in RSCU, we expect that "late" viral RSCUs would tend to be more highly correlated with human RSCU than "early" viral RSCUs. In fact, tests of significance suggest that this is the case. However, closer examination of the data revealed that the apparent trend towards human RSCU can be attributed to the homogenization of the codon usage by mutation pressure rather than host adaptation.
Determination of the GaAs/AlAs Superlattice Period from the First-Order Superlattice Bragg Reflection
Authors: Tanaka Chikako , Komiya Satoshi , Muto Shunichi , Umebu Itsuo , Iida Atsuo
Published: February 2005

The thickness of the GaAs/AlAs superlattice period determined from the 1st-order Bragg reflection alone is shown to be expressed by a mean value ±some uncertainty e.g, 14±0.01-60±0.8Å. The uncertainty is reduced when the thickness of the two layers in a period proves to be so close that the 2nd-order reflection is nondetectable. The estimated thickness using synchrotron radiation agrees well with that obtained from TEM.
Influences of Alignment Materials and LC Layer Thickness on AC Field-Stabilization Phenomena of Ferroelectric Liquid Crystals
Authors: Umeda Takao , Nagata Tetsuya , Mukoh Akio , Hori Yasuro
Published: February 2005

The influences of alignment materials and LC layer thickness on an AC-field stabilization phenomena have been studied. Ferroelectric LC material with a dielectric anisotropy of -2.7 and two kinds of polyimide resins (A,B) for alignment materials were prepared. Polyimide resin A has a rigid structure and its molecular chain is rod-like, while polyimide resin B has a somewhat zigzag structure and a molecular chain which is flexibly coiled. The amplitude E
h of an AC electric field which is necessary for stabilizing LC molecules was measured and the following results were obtained: (1) E
h of the LC cell using polyimide resin B was smaller than that of the LC cell using polyimide resin A. (2) As the LC layer thickness became smaller, the amplitude of E
h became larger.
Optical Second-Harmonic Generation in Single Crystals of Thiosemicarbazide Cadmium Bromide Hydrate (Cd(NH2NHCSNH2)Br2·H2O)
Authors: Wang W. S. , Sutter K. , Bosshard Ch. , Pan Z. , Arend H. , Günter P. , Chapuis G. , Nicolo F.
Published: February 2005

A new nonlinear optical organic-inorganic crystal, thiosemicarbazide cadmium bromide hydrate (TSCCB), with crystal class m has been grown by a temperature-lowering technique (TLT) and a temperature-difference technique (TDT). The crystal structure of TSCCB is reported. Its linear and nonlinear optical properties have been investigated. The highest measured nonlinear optical susceptibility is d
max = 2.8 pm/V.
Preparation and Characterizations of Al3Ta Intermetallic Compound Films
Authors: Sasaki Katsutaka , Noya Atsushi , Umezawa Toshiji
Published: February 2005

The intermetallic compound film of Al3Ta was prepared by co-sputtering at a substrate temperature as low as 400degC. Effects of subsequent annealing in air on the grain growth and on the electrical properties were examined. It is revealed from the Auger electron spectroscopy analysis that the film surface is covered with a thin Al2O3 layer which protects the film from further oxidation. The films obtained are sufficiently applicable as a metallization material for large-scale integrated circuits.
Comparison of Gettering Techniques by Means of Intentional Quantitative Cu Contamination
Authors: Sano Masakazu , Horai Masataka , Miyazaki Morimasa , Fujino Nobukatsu , Shiraiwa Toshio
Published: February 2005

Gettering is a very important technique for the LSI process. The effects of gettering techniques such as intrinsic gettering (IG), backside damage (BD), and polysilicon gettering (PG) were investigated by the MOS c-t method after intentional quantitative Cu contamination. These three techniques showed different gettering behaviors in the heat treatments simulating a device heat process. IG and BD were not effective in the beginning of the heat process, but they began to show stronger gettering effects with heat treatments and gained sufficient abilities. The IG kept its effect until the end of the heat process, but BD's effect decreased with subsequent heat treatments. PG had a sufficient gettering effect from the beginning of the heat process, but PG also showed a decrease of gettering effect at the end of the heat process.
The Off-Valency Additive Effect and Its Influence on the Curie Peak of the Barium Titanate (BaTiO3)/Polyvinylidene Fluoride (PVDF) Composite
Authors: Muralidhar C.
Published: February 2005

The curie peak is shifted to around 150degC in BaTiO3. The curie peak in the BaTiO3/PVDF composite of 70% wt. fraction of BaTiO3 has been found to be absent. XRD studies show the elimination and suppression of some of the peaks of PVDF in the composite. The results are explained on the basis of an ultrafine particle size of BaTiO3 (about 1 µm), an off-valency additive effect and internal stresses.
Y–Ba–Cu–O Thin Films Formed on Alumina Ceramic Substrates Coated with Yttria Stabilized Zirconia Layer
Authors: Onuma Yoshiharu , Kamimura Kiichi , Nakao Masato , Kunugi Kazumasa , Kubota Miki
Published: February 2005

Y–Ba–Cu–O thin films have been deposited by DC magnetron sputtering on alumina ceramic substrate coated with yttria stabilized zirconia layer (YSZ). The YSZ layer acted as the buffer layer between the alumina ceramic substrate and the Y–Ba–Cu–O thin film. The temperatures of superconducting onset and zero resistance were 95 K and 47 K, respectively.
Structure of Lattice-Matched CaxSr1-xF2 Epilayers on GaAs(111)B Surface Analyzed by the X-Ray Standing-Wave Method
Authors: Saitoh Yoshiharu , Hashizume Hiroo , Tsutsui Kazuo
Published: February 2005

The atomic structure of a single-crystal Ca
x
Sr1-x
F2(x=0.43) film grown on GaAs(111)B surface has been determined by the X-ray standing-wave technique. A new method has been applied which allows complete analysis of mismatched structures using a single specimen. (Ca, Sr) atoms at the interface are found to be seven-coordinated, supporting the previously proposed growth model of epitaxial cubic fluoride films. The atomic layer spacing across the interface is contracted by 0.37 Å, compared with that calculated from the bulk bond lengths. The film is strained in such a way that the (111) interplanar distance is contracted by 0.28%, although the bulk-mixed fluoride exactly lattice matches GaAs at room temperature. The study is based on a theoretical reinvestigation of the standing-wave position with respect to atomic planes in absorbing noncentrosymmetric crystals.
Quick Measurement and Digital Data Handling for Langmuir Probes
Authors: Fujita Fumiyuki , Yamazaki Hatsuo
Published: February 2005

A quick measurement and data processing system for Langmuir probes was developed based on a digital technique. This system enabled us to avoid the effect of probe contamination and plasma-state variations on probe characteristics. For noise reduction, the system had an averaging function by digital accumulation of data from multiple scanning. A set of personal computer programs which automatically determine the electron temperature and density from probe-characteristic data was also developed. The system was applied to a negative glow plasma, and the plasma parameters were successfully determined.
Light Scattering Measurements of Gaussian Laser Beam in Random Media of Fog and Smoke
Authors: Ooyama Noboru , Miyazaki Yasumitsu
Published: February 2005

Electromagnetic scattering of Gaussian laser beam by microheterogeneities was discussed. The local properties of the random medium such as water droplet clouds and smoke are studied experimentally. The angular intensity distributions of the scattered light are compared with theoretical results of statistical theory with the help of correlation functions of inhomogeneities devised by the author. From comparison between experimental and theoretical results, it is found that a few kinds of fluctuations of different sizes caused by different origins are mixed. One of the correlation lengths of fluctuations is expressed as almost equivalent to the mean diameter of scatterers, while others are less.
Structure Factors of InP Determined by the Pendellösung Method Using White Radiation
Authors: Kobayashi Kazuyoshi , Takama Toshihiko , Tohno Shun-ichi , Sato Shin'ichi
Published: February 2005

The Pendellösung intensity beats in wavelength scale were measured to determine the structure factors of InP crystal by the energy-dispersive diffraction method. The clear beats obtained for eleven low-order reflections from the 111 to 440 reflections were analyzed to evaluate the structure factors with their wavelength dependence on the basis of the dynamical diffraction theory. The values were different from those measured by Sirota and Gololobov (Acta Crystallogr. A25 (1969) 223) using the powder diffraction method, especially for high-order reflections. A discussion is made on the charge density of valence electrons using the obtained structure factors and the tetrahedral charge distortion model. The measured wavelength dependence of the structure factors can be interpreted well by the anomalous dispersion terms of Cromer and Liberman (J. Chem. Phys. 53 (1970) 1891).
A Note on the Electronic Band Structures of (111) Superlattices of III–V Semiconductor Compounds
Authors: Nara Shigetoshi
Published: February 2005

The electronic band structures of (111) superlattices of III-V semiconductors are considered. In the (IIIA-VA)
m
/(IIIB-VB)
n
type of superlattices, the space groups are C3v
1 for m+n=3l and C3v
5 for m+n≠3l, where m, n and l are integers. The Bravais lattice of the former is hexagonal and that of the latter is rhombohedral. Band folding occurs along the (111) direction of the original f.c.c. Brillouin zone of zincblend structure. With the inclusion of spin orbit interaction, the top of the valence band, which is sixfold degenerate in bulk form, splits into three levels, each of which is twofold degenerate. None of the levels is an eigenstate of the total angular momentum. As a numerical example, the band structure of (111) superlattice, (GaAs)1/(AlAs)1 is calculated by means of an improved tight binding method both with and without the inclusion of spin orbit interaction.
Photoconductivity in Thin Films of a-In40Se30Te30
Authors: Maan A. S. , Goyal D. R. , Kumar A.
Published: February 2005

Photoconductivity in thin film of a-In40Se30Te30, obtained by vacuum evaporation, was studied at different temperatures and illumination intensities. Photoconductivity increases exponentially with T in the range 310–370 K. Intensity dependence of photocurrent at various temperatures reveals power dependence of incident radiation. Transient photoconductivity observations made at different temperatures and intensities show that rise and decay of photocurrent are quite slow in the present sample. The rise and decay were found to be exponential with the same value of recombination time.
Hysteresis-like Characteristics of Ring-Shaped Ceramic Superconductors
Authors: Takeoka Akio , Hasunuma Masahiko , Sakaiya Shoji , Kishi Yasuo , Kuwano Yukinori
Published: February 2005

We investigated the residual magnetic field characteristics of ring-shaped ceramic superconductors in a Y–Ba–Cu–O system with high-T
c. The residual magnetic field of a superconducting ring to which external fields were applied showed hysteresis-like characteristics. The induced persistent current in the saturated ring corresponded to the critical current of the ring. The residual magnetic field of a ring with asymmetric current paths, supplied by external currents, was zero while one of the branch currents remained below the critical current; but a residual magnetic field appeared at currents above the critical current as a result of a difference between the inductances of the paths. It became saturated and showed hysteresis-like characteristic when both branch currents exceeded the critical current. Saturated magnetic fields are thus subject to critical current of the ring.