bluuebunny/crossref_metadata_2025 huggingface dataset:
Structure-Function Analysis of Rotavirus NSP2 Octamer by Using a Novel Complementation System
Authors: Taraporewala Zenobia F. , Jiang Xiaofang , Vasquez-Del Carpio Rodrigo , Jayaram Hariharan , Prasad B. V. Venkataram , Patton John T.
Published: July 2006

Viral inclusion bodies, or viroplasms, that form in rotavirus-infected cells direct replication and packaging of the segmented double-stranded RNA (dsRNA) genome. NSP2, one of two rotavirus proteins needed for viroplasm assembly, possesses NTPase, RNA-binding, and helix-unwinding activities. NSP2 of the rotavirus group causing endemic infantile diarrhea (group A) was shown to self-assemble into large doughnut-shaped octamers with circumferential grooves and deep clefts containing nucleotide-binding histidine triad (HIT)-like motifs. Here, we demonstrate that NSP2 of group C rotavirus, a group that fails to reassort with group A viruses, retains the unique architecture of the group A octamer but differs in surface charge distribution. By using an NSP2-dependent complementation system, we show that the HIT-dependent NTPase activity of NSP2 is necessary for dsRNA synthesis, but not for viroplasm formation. The complementation system also showed that despite the retention of the octamer structure and the HIT-like fold, group C NSP2 failed to rescue replication and viroplasm formation in NSP2-deficient cells infected with group A rotavirus. The distinct differences in the surface charges on the Bristol and SA11 NSP2 octamers suggest that charge complementarity of the viroplasm-forming proteins guides the specificity of viroplasm formation and, possibly, reassortment restriction between rotavirus groups.
Recombinant Nipah Virus Vaccines Protect Pigs against Challenge
Authors: Weingartl Hana M. , Berhane Yohannes , Caswell Jeff L. , Loosmore Sheena , Audonnet Jean-Christophe , Roth James A. , Czub Markus
Published: July 2006

Nipah virus (NiV), of the familyParamyxoviridae, was isolated in 1999 in Malaysia from a human fatality in an outbreak of severe human encephalitis, when human infections were linked to transmission of the virus from pigs. Consequently, a swine vaccine able to abolish virus shedding is of veterinary and human health interest. Canarypox virus-based vaccine vectors carrying the gene for NiV glycoprotein (ALVAC-G) or the fusion protein (ALVAC-F) were used to intramuscularly immunize four pigs per group, either with 108PFU each or in combination. Pigs were boosted 14 days postvaccination and challenged with 2.5 × 105PFU of NiV two weeks later. The combined ALVAC-F/G vaccine induced the highest levels of neutralization antibodies (2,560); despite the low neutralizing antibody levels in the F vaccinees (160), all vaccinated animals appeared to be protected against challenge. Virus was not isolated from the tissues of any of the vaccinated pigs postchallenge, and a real-time reverse transcription (RT)-PCR assay detected only small amounts of viral RNA in several samples. In challenge control pigs, virus was isolated from a number of tissues (104.4PFU/g) or detected by real-time RT-PCR. Vaccination of the ALVAC-F/G vaccinees appeared to stimulate both type 1 and type 2 cytokine responses. Histopathological findings indicated that there was no enhancement of lesions in the vaccinees. No virus shedding was detected in vaccinated animals, in contrast to challenge control pigs, from which virus was isolated from the throat and nose (102.9PFU/ml). Based on the data presented, the combined ALVAC-F/G vaccine appears to be a very promising vaccine candidate for swine.
Infection of Human Airway Epithelium by Human and Avian Strains of Influenza A Virus
Authors: Thompson Catherine I. , Barclay Wendy S. , Zambon Maria C. , Pickles Raymond J.
Published: July 2006

We describe the characterization of influenza A virus infection of an established in vitro model of human pseudostratified mucociliary airway epithelium (HAE). Sialic acid receptors for both human and avian viruses, α-2,6- and α-2,3-linked sialic acids, respectively, were detected on the HAE cell surface, and their distribution accurately reflected that in human tracheobronchial tissue. Nonciliated cells present a higher proportion of α-2,6-linked sialic acid, while ciliated cells possess both sialic acid linkages. Although we found that human influenza viruses infected both ciliated and nonciliated cell types in the first round of infection, recent human H3N2 viruses infected a higher proportion of nonciliated cells in HAE than a 1968 pandemic-era human virus, which infected proportionally more ciliated cells. In contrast, avian influenza viruses exclusively infected ciliated cells. Although a broad-range neuraminidase abolished infection of HAE by human parainfluenza virus type 3, this treatment did not significantly affect infection by influenza viruses. All human viruses replicated efficiently in HAE, leading to accumulation of nascent virus released from the apical surface between 6 and 24 h postinfection with a low multiplicity of infection. Avian influenza A viruses also infected HAE, but spread was limited compared to that of human viruses. The nonciliated cell tropism of recent human H3N2 viruses reflects a preference for the sialic acid linkages displayed on these cell types and suggests a drift in the receptor binding phenotype of the H3 hemagglutinin protein as it evolves in humans away from its avian virus precursor.
Characterization of an Amino-Terminal Dimerization Domain from Retroviral Restriction Factor Fv1
Authors: Bishop Kate N. , Mortuza Gulnahar B. , Howell Steven , Yap Melvyn W. , Stoye Jonathan P. , Taylor Ian A.
Published: July 2006

The Fv1 protein is an endogenous factor in mice that confers resistance to infection by certain classes of murine leukemia virus, a phenomenon referred to as restriction. The mechanism of restriction is not understood, and the low endogenous level of Fv1 in cells has prevented any biochemical or biophysical analysis of the protein. We have now purified recombinant Fv1
n
protein from a baculovirus system and demonstrate that Fv1 exists in a multimeric form. Furthermore, we have mapped the position of two domains within the protein using limited proteolysis. Biophysical characterization of the N-terminal domain reveals that it comprises a highly helical and extended dimeric structure. Based on these biochemical and biophysical data, we propose a model for the arrangement of domains in Fv1 and suggest that dimerization of the N-terminal domain is necessary for Fv1 function to allow the protein to interact with multiple capsid protomers in retroviral cores.
CD4+T-Cell Responses to Epstein-Barr Virus Nuclear Antigen EBNA1 in Chinese Populations Are Highly Focused on Novel C-Terminal Domain-Derived Epitopes
Authors: Tsang C. W. , Lin X. , Gudgeon N. H. , Taylor G. S. , Jia H. , Hui E. P. , Chan A. T. C. , Lin C. K. , Rickinson A. B.
Published: July 2006

Epstein-Barr virus nuclear antigen EBNA1, the one viral protein uniformly expressed in nasopharyngeal carcinoma (NPC), represents a prime target for T-cell-based immunotherapy. However, little is known about the EBNA1 epitopes, particularly CD4 epitopes, presented by HLA alleles in Chinese people, the group at highest risk for NPC. We analyzed the CD4+T-cell responses to EBNA1 in 78 healthy Chinese donors and found marked focusing on a small number of epitopes in the EBNA1 C-terminal region, including a DP5-restricted epitope that was recognized by almost half of the donors tested and elicited responses able to recognize EBNA1-expressing, DP5-positive target cells.
Prion Strain-Dependent Differences in Conversion of Mutant Prion Proteins in Cell Culture
Authors: Atarashi Ryuichiro , Sim Valerie L. , Nishida Noriyuki , Caughey Byron , Katamine Shigeru
Published: July 2006

Although the protein-only hypothesis proposes that it is the conformation of abnormal prion protein (PrP
Sc
) that determines strain diversity, the molecular basis of strains remains to be elucidated. In the present study, we generated a series of mutations in the normal prion protein (PrP
C
) in which a single glutamine residue was replaced with a basic amino acid and compared their abilities to convert to PrP
Sc
in cultured neuronal N2a58 cells infected with either the Chandler or 22L mouse-adapted scrapie strain. In mice, these strains generate PrP
Sc
of the same sequence but different conformations, as judged by infrared spectroscopy. Substitutions at codons 97, 167, 171, and 216 generated PrP
C
that resisted conversion and inhibited the conversion of coexpressed wild-type PrP in both Chandler-infected and 22L-infected cells. Interestingly, substitutions at codons 185 and 218 gave strain-dependent effects. The Q185R and Q185K PrP were efficiently converted to PrP
Sc
in Chandler-infected but not 22L-infected cells. Conversely, Q218R and Q218H PrP were converted only in 22L-infected cells. Moreover, the Q218K PrP exerted a potent inhibitory effect on the conversion of coexpressed wild-type PrP in Chandler-infected cells but had little effect on 22L-infected cells. These results show that two strains with the same PrP sequence but different conformations have differing abilities to convert the same mutated PrP
C
.
Cleavage Map and Proteolytic Processing of the Murine Norovirus Nonstructural Polyprotein in Infected Cells
Authors: Sosnovtsev Stanislav V. , Belliot Gaël , Chang Kyeong-OK , Prikhodko Victor G. , Thackray Larissa B. , Wobus Christiane E. , Karst Stephanie M. , Virgin Herbert W. , Green Kim Y.
Published: July 2006

Murine
norovirus (MNV) is presently the only member of the genus
Norovirus
in the
Caliciviridae
that can be propagated
in cell culture. The goal of this study was to elucidate the
proteolytic processing strategy of MNV during an authentic replication
cycle in cells. A proteolytic cleavage map of the ORF1 polyprotein was
generated, and the virus-encoded 3C-like (3CL) proteinase (Pro)
mediated cleavage at five dipeptide cleavage sites,
341
E/G
342
, Q
705
/N
706
,
870
E/G
871
,
994
E/A
995
, and
1177
Q/G
1178
, that defined the borders of six
proteins with the gene order p38.3 (Nterm)-p39.6
(NTPase)-p18.6-p14.3 (VPg)-p19.2 (Pro)-p57.5 (Pol). Bacterially
expressed MNV 3CL Pro was sufficient to mediate
trans
cleavage
of the ORF1 polyprotein containing the mutagenized Pro sequence into
products identical to those observed during cotranslational processing
of the authentic ORF1 polyprotein in vitro and to those observed in
MNV-infected cells. Immunoprecipitation and Western blot analysis of
proteins produced in virus-infected cells demonstrated efficient
cleavage of the proteinase-polymerase precursor. Evidence for
additional processing of the Nterm protein in MNV-infected cells by
caspase 3 was obtained, and Nterm sequences
118
DRPD
121
and
128
DAMD
131
were mapped as caspase 3 cleavage sites by site-directed mutagenesis.
The availability of the MNV nonstructural polyprotein cleavage map in
concert with a permissive cell culture system should facilitate studies
of norovirus
replication.
Requirement of the N-Terminal Region of Orthobunyavirus Nonstructural Protein NSm for Virus Assembly and Morphogenesis
Authors: Shi Xiaohong , Kohl Alain , Léonard Vincent H. J. , Li Ping , McLees Angela , Elliott Richard M.
Published: July 2006

The nonstructural protein NSm of Bunyamwera virus (BUNV), the prototype of the
Bunyaviridae
family, is encoded by the M segment in a polyprotein precursor, along with the virion glycoproteins, in the order Gn-NSm-Gc. As little is known of its function, we examined the intracellular localization, membrane integrality, and topology of NSm and its role in virus replication. We confirmed that NSm is an integral membrane protein and that it localizes in the Golgi complex, together with Gn and Gc. Coimmunoprecipitation assays and yeast two-hybrid analysis demonstrated that NSm was able to interact with other viral proteins. NSm is predicted to contain three hydrophobic (I, III, and V) and two nonhydrophobic (II and IV) domains. The N-terminal nonhydrophobic domain II was found in the lumen of an intracellular compartment. A novel BUNV assembly assay was developed to monitor the formation of infectious virus-like-particles (VLPs). Using this assay, we showed that deletions of either the complete NSm coding region or domains I, II, and V individually seriously compromised VLP production. Consistently, we were unable to rescue viable viruses by reverse genetics from cDNA constructs that contained the same deletions. However, we could generate mutant BUNV with deletions in NSm domains III and IV and also a recombinant virus with the green fluorescent protein open reading frame inserted into NSm domain IV. The mutant viruses displayed differences in their growth properties. Overall, our data showed that the N-terminal region of NSm, which includes domain I and part of domain II, is required for virus assembly and that the C-terminal hydrophobic domain V may function as an internal signal sequence for the Gc glycoprotein.
PML Contributes to a Cellular Mechanism of Repression of Herpes Simplex Virus Type 1 Infection That Is Inactivated by ICP0
Authors: Everett Roger D. , Rechter Sabine , Papior Peer , Tavalai Nina , Stamminger Thomas , Orr Anne
Published: July 2006

Promyelocytic leukemia (PML) nuclear bodies (also known as ND10) are nuclear substructures that contain several proteins, including PML itself, Sp100, and hDaxx. PML has been implicated in many cellular processes, and ND10 are frequently associated with the replicating genomes of DNA viruses. During herpes simplex virus type 1 (HSV-1) infection, the viral regulatory protein ICP0 localizes to ND10 and induces the degradation of PML, thereby disrupting ND10 and dispersing their constituent proteins. ICP0-null mutant viruses are defective in PML degradation and ND10 disruption, and concomitantly they initiate productive infection very inefficiently. Although these data are consistent with a repressive role for PML and/or ND10 during HSV-1 infection, evidence in support of this hypothesis has been inconclusive. By use of short interfering RNA technology, we demonstrate that depletion of PML increases both gene expression and plaque formation by an ICP0-negative HSV-1 mutant, while having no effect on wild-type HSV-1. We conclude that PML contributes to a cellular antiviral repression mechanism that is countered by the activity of ICP0.
The L2 Minor Capsid Protein of Low-Risk Human Papillomavirus Type 11 Interacts with Host Nuclear Import Receptors and Viral DNA
Authors: Bordeaux J. , Forte S. , Harding E. , Darshan M. S. , Klucevsek K. , Moroianu J.
Published: July 2006

Analysis of the interactions of low-risk human papillomavirus type 11 (HPV11) L2 with karyopherin β (Kap β) nuclear import receptors revealed that L2 interacted with Kap β
1
, Kap β
2
, and Kap β
3
and formed a complex with the Kap α
2
β
1
heterodimer. HPV11 L2 contains two nuclear localization signals (NLSs)—in the N terminus and the C terminus—that could mediate its nuclear import via a classical pathway. Each NLS was functional in vivo, and deletion of both of them abolished L2 nuclear localization. Both NLSs interacted with the viral DNA. Thus, HPV11 L2 can interact with several karyopherins and the viral DNA and may enter the nucleus via multiple pathways.
Differential Role of Sp100 Isoforms in Interferon-Mediated Repression of Herpes Simplex Virus Type 1 Immediate-Early Protein Expression
Authors: Negorev Dmitri G. , Vladimirova Olga V. , Ivanov Alexey , Rauscher Frank , Maul Gerd G.
Published: July 2006

Nuclear domains called ND10 or PML nuclear bodies contain interferon (IFN)-upregulated proteins like PML and Sp100. Paradoxically, herpes simplex virus 1 (HSV-1) begins its transcriptional cascade at aggregates of ND10-associated proteins, which in turn are destroyed by the HSV-1 immediate-early protein ICP0. While PML is essential in the formation of ND10, the function of Sp100 in the cells' defense against viral infection is unknown. In this study we investigated the potential antiviral effect of IFN-β-induced Sp100. We found that IFN-β treatment leads to a differential accumulation of four Sp100 isoforms in different cell lines. Using an HEK293 cell line derivative, 293-S, producing no detectable amounts of Sp100 even after IFN exposure, we analyzed individual Sp100 isoforms for their effect on HSV-1 infection. Sp100 isoforms B, C, and HMG, but not Sp100A, suppressed ICP0 and ICP4 early after infection. Isoforms B, C, and HMG suppressed expression from the ICP0 promoter in transient transfection, whereas Sp100A enhanced expression. Moreover, Sp100A localized in ND10, whereas the repressive isoforms were either dispersed within the nucleus or, at unphysiologically higher expression levels, formed new aggregates. The repressive activity was dependent on an intact SAND domain, since Sp100B bearing a W655Q mutation in the SAND domain lost this repressive activity and accumulated in ND10. Using RNA interference to knock down the repressive Sp100 isoforms B, C, and HMG, we find that they are an essential part of the IFN-β-mediated suppression of ICP0 expression. These data suggest that repression by the Sp100 isoforms B, C, and HMG takes place outside of ND10 and raise the possibility that viral genomes at Sp100A accumulations are more likely to start their transcription program because of a more permissive local environment.
OCTONIONIC VERSION OF DIRAC EQUATIONS
Authors: GOGBERASHVILI MERAB
Published: July 2006

It is shown that a simple continuity condition in the algebra of split octonions suffices to formulate a system of differential equations that are equivalent to the standard Dirac equations. In our approach the particle mass and electromagnetic potentials are part of an octonionic gradient function together with the space–time derivatives. As distinct from previous attempts to translate the Dirac equations into different number systems here the wave functions are real split octonions and not bi-spinors. To formulate positively defined probability amplitudes four different split octonions (transforming into each other by discrete transformations) are necessary, rather then two complex wave functions which correspond to particles and antiparticles in usual Dirac theory.
HARD DIFFRACTIVE SCATTERING FACTORIZATION FROM ηc AND γ ASSOCIATED PRODUCTION AT TEVATRON AND LHC
Authors: YAN ZHAN-YUAN , DUAN CHUN-GUI
Published: July 2006

Based on IS model, the cross-sections of associated ηc and γ diffractive production in [Formula: see text] collision are calculated. Under the framework of NRQCD factorization formalism for quarkonia production, the dominant contribution to associated ηc and γ production comes from color octet [Formula: see text] subprocess, the color octet matrix element of [Formula: see text] is related to that of [Formula: see text] of J/ψ by the heavy quark spin symmetry. Because the value of color octet matrix element of [Formula: see text] of J/ψ is determined by the large PTJ/ψ production data, the prediction of ηc and γ is more reliable. The ratio of diffractive to inclusive cross-sections is independent of the values of color octet matrix elements, which is sensitive to the gluon factor of the Pomeron and renormalized Pomeron flux factors. So experimental measurement of this ratio can give us more information of the nature of Pomeron and test the assumption of diffractive hard scattering factorization.
ASYMPTOTIC QUASINORMAL MODES OF d-DIMENSIONAL SCHWARZSCHILD BLACK HOLE WITH GAUSS–BONNET CORRECTION
Authors: CHAKRABARTI SAYAN K. , GUPTA KUMAR S.
Published: July 2006

We obtain an analytic expression for the highly damped asymptotic quasinormal mode frequencies of the (d ≥ 5)-dimensional Schwarzschild black hole modified by the Gauss–Bonnet term, which appears in string derived models of gravity. The analytic expression is obtained under the string inspired assumption that there exists a minimum length scale in the system and in the limit when the coupling in front of the Gauss–Bonnet term in the action is small. Although there are several similarities of this geometry with that of the Schwarzschild black hole, the asymptotic quasinormal mode frequencies are quite different. In particular, the real part of the asymptotic quasinormal frequencies for this class of single horizon black holes is not proportional to log (3).
NEW PHYSICS EFFECTS IN THE FLAVOR-CHANGING NEUTRAL COUPLINGS OF THE TOP QUARK
Authors: LARIOS F. , MARTÍNEZ R. , PÉREZ M. A.
Published: July 2006

We survey the flavor-changing neutral couplings (FCNC) of the top quark predicted by some extensions of the Standard Model: THDM, SUSY, Left–Right symmetric, TC2, 331, and models with extra quarks. Since the expected sensitivity of the LHC and ILC for the tcV (V = γ, g, Z) and tcH couplings is of order of a few percent, we emphasize the importance of any new physics effect that gives a prediction for these FCNC couplings within this limit. We also review the constraints imposed on these couplings from low-energy precision measurements.
TWO-PHOTON NONLINEAR INTERACTION MEDIATED BY CAVITY QUANTUM ELECTRODYNAMICS SYSTEMS
Authors: KOSHINO KAZUKI , ISHIHARA HAJIME
Published: July 2006

Exploiting the field-amplification effect of a cavity, the possibility of optical nonlinearity by only two photons was indicated experimentally. In the present article, we review our recent analysis of the two-photon dynamics in a cavity quantum electrodynamics (QED) system. Since a cavity-QED system is highly dispersive around its resonances, the shapes of photonic pulses are significantly deformed through interaction with the system. Thus, the present analysis is based on a formalism beyond single-mode approximations. The external photon field is treated rigorously as a continuum, which enables us to handle the two-photon wavefunction in the space representation. The degree of optical nonlinearity in a two-photon state is quantified by comparing the output wavefunction with the linear output wavefunction. It is revealed that the semiclassical optical response theory can be applied for evaluation of the two-photon optical nonlinearity. The two-photon nonlinearity appears not purely as a phase shift in the output wavefunction. The degradation of the fidelity between the output wavefunction and the linear output wavefunction always occurs, which hinders the application of this nonlinear effect as a quantum phase gate. The optimum condition for maximizing the two-photon nonlinearity is clarified, suggesting that pulse shape control is more essential than the Q-value control of the cavity QED system.
ADDENDUM: NEW INTERPRETATION OF HOMOTOPY PERTURBATION METHOD
Authors: HE JI-HUAN
Published: July 2006

The present work constitutes a guided tour through the mathematics needed for a proper understanding of homotopy perturbation method as applied to various nonlinear problems. It gives a new interpretation of the concept of constant expansion in the homotopy perturbation method.
OSCILLATION PROCESS OF BUBBLE IN POLYMERS
Authors: MENG QING-YUN , WU DA-MING
Published: July 2006

A method of dispersing nanogranules in polymer utilizing the stretching, compression, and shearing effects induced by bubble inflation or oscillation in a polymer melt undergoing foaming is reported. It can be known from theoretical calculation that the bubble inflation is very fast (about μs). The other result of theoretical calculation is that the bubble can oscillate when appearing appropriate condition in polymer. The successful dispersion of nanogranules in a polymer melt by bubble inflation has been shown by experiment. Comparison of a theoretical analysis of the dispersion effect is given by the ISBS method with the results from experimental scanning electron microscope micrographs, given reasonable grounds for support of our hypotheses.
TEMPLATED SYNTHESIS OF NANOSTRUCTURED COBALT THIN FILM FOR POTENTIAL TERABIT MAGNETIC RECORDING
Authors: LEE U-HWANG , PARK JONG BAE , KIM SEONG KYU , KWON YOUNG-UK
Published: July 2006

An array of cobalt nanorods of 10 nm in diameter and 14 nm of rod-to-rod distance was fabricated by electrochemical deposition technique into the pores of a mesoporous silica thin film formed on a Pt -coated Si wafer substrate. The cobalt nanorods are highly crystalline with the fcc structure. The magnetic hysterisis data at 300 K show that Co @silica nanocomposite film has strong magnetization anisotropy. Atomic and magnetic force microscopic data on this film revealed the possibility that each cobalt nanorod in the array can be individually magnetized. The number density of the cobalt nanorods is very high with 6 × 1012 per in2, high enough to develop into a terabit magnetic memory device.
ELECTRICAL TRANSPORT PROPERTIES AND FIELD EFFECT TRANSISTORS OF CARBON NANOTUBES
Authors: DAI HONGJIE , JAVEY ALI , POP ERIC , MANN DAVID , KIM WOONG , LU YUERUI
Published: July 2006

This paper presents a review on our recent work on carbon nanotube field effect transistors, including the development of ohmic contacts, high-κ gate dielectric integration, chemical functionalization for conformal dielectric deposition and pushing the performance limit of nanotube FETs by channel length scaling. Due to the importance of high current operations of electronic devices, we also review the high field electrical transport properties of nanotubes on substrates and in freely suspended forms. Owing to their unique properties originating from their crystalline 1D structure and the strong covalent carbon–carbon bonding configuration, carbon nanotubes are highly promising as building blocks for future electronics. They are found to perform favorably in terms of ON-state current density as compared to the existing silicon technology, owing to their superb electron transport properties and compatibility with high-κ gate dielectrics. Future directions and challenges for carbon nanotube-based electronics are also discussed.
DIRECT GROWTH OF MULTI-WALLED CARBON NANOTUBES ON SHARP TIPS FOR ELECTRON MICROSCOPY
Authors: MANN M. , TEO K. B. K. , MILNE W. I. , TESSNER T.
Published: July 2006

The favorable electron optical properties of carbon nanotubes (CNTs) have been studied in detail, but the application to electron sources has been limited by the complexity of the fabrication process. We report the use of Plasma Enhanced Chemical Vapor Deposition (PECVD) for the direct deposition of multi-walled CNTs onto the apex of sharply etched tungsten tips, aligned to the vertical axis of the tips. We show that these emitters have excellent stability.
Evolutionary Biology of Centipedes (Myriapoda: Chilopoda)
Authors: Edgecombe Gregory D. , Giribet Gonzalo
Published: July 2006

New insights into the anatomy, systematics, and biogeography of centipedes have put these predatory terrestrial arthropods at the forefront of evolutionary studies. Centipedes have also played a pivotal role in understanding high-level arthropod relationships. Their deep evolutionary history, with a fossil record spanning 420 million years, explains their current worldwide distribution. Recent analyses of combined morphological and molecular data provide a stable phylogeny that underpins evolutionary interpretations of their biology. The centipede trunk, with its first pair of legs modified into a venom-delivering organ followed by 15 to 191 leg pairs, is a focus of arthropod segmentation studies. Gene expression studies and phylogenetics shed light on key questions in evolutionary developmental biology concerning the often group-specific fixed number of trunk segments, how some centipedes add segments after hatching whereas others hatch with the complete segment count, the addition of segments through evolution, and the invariably odd number of leg-bearing trunk segments.
MYPT1 mutants demonstrate the importance of aa 888–928 for the interaction with PKGIα
Authors: Given Allison M. , Ogut Ozgur , Brozovich Frank V.
Published: July 2006

During nitric oxide signaling, type Iα cGMP-dependent protein kinase (PKGIα) activates myosin light chain (MLC) phosphatase through an interaction with the 130-kDa myosin targeting subunit (MYPT1), leading to dephosphorylation of 20-kDa MLC and vasodilatation. It has been suggested that the MYPT1-PKGIα interaction is mediated by the COOH-terminal leucine zipper (LZ) of MYPT1 and the NH2-terminal LZ of PKGIα (HK Surks and ME Mendelsohn. Cell Signal 15: 937–944, 2003; HK Surks et al. Science 286: 1583–1587, 1999), but we previously showed that PKGIα interacts with LZ-positive (LZ+) and LZ-negative (LZ−) MYPT1 isoforms ( 13 ). Interestingly, PKGIα is known to preferentially bind to RR and RK motifs (WR Dostmann et al. Proc Natl Acad Sci USA 97: 14772–14777, 2000), and there is an RK motif within the aa 888–928 sequence of MYPT1 in LZ+ and LZ− isoforms. Thus, to localize the domain of MYPT1 important for the MYPT1-PKGIα interaction, we designed four MYPT1 fragments that contained both the aa 888–928 sequence and the downstream LZ domain (MYPT1FL), lacked both the aa 888–928 sequence and the LZ domain (MYPT1TR), lacked only the aa 888–928 sequence (MYPT1SO), or lacked only the LZ domain (MYPT1TR2). Using coimmunoprecipitation, we found that only the fragments containing the aa 888–928 sequence (MYPT1FL and MYPT1TR2) were able to form a complex with PKGIα in avian smooth muscle tissue lysates. Furthermore, mutations of the RK motif at aa 916–917 (R916K917) to AA decreased binding of MYPT1 to PKGIα in chicken gizzard lysates; these mutations had no effect on binding in chicken aorta lysates. However, mutation of R916K917 to E916E917 eliminated binding, suggesting that one factor important for the PKGIα-MYPT1 interaction is the charge at aa 916–917. These results suggest that, during cGMP-mediated signaling, aa 888–928 of MYPT1 mediate the PKGIα-MYPT1 interaction.
Mitochondrial Ca2+-induced K+ influx increases respiration and enhances ROS production while maintaining membrane potential
Authors: Heinen André , Camara Amadou K. S. , Aldakkak Mohammed , Rhodes Samhita S. , Riess Matthias L. , Stowe David F.
Published: July 2006

We recently demonstrated a role for altered mitochondrial bioenergetics and reactive oxygen species (ROS) production in mitochondrial Ca2+-sensitive K+ (mtKCa) channel opening-induced preconditioning in isolated hearts. However, the underlying mitochondrial mechanism by which mtKCa channel opening causes ROS production to trigger preconditioning is unknown. We hypothesized that submaximal mitochondrial K+ influx causes ROS production as a result of enhanced electron flow at a fully charged membrane potential (ΔΨm). To test this hypothesis, we measured effects of NS-1619, a putative mtKCa channel opener, and valinomycin, a K+ ionophore, on mitochondrial respiration, ΔΨm, and ROS generation in guinea pig heart mitochondria. NS-1619 (30 μM) increased state 2 and 4 respiration by 5.2 ± 0.9 and 7.3 ± 0.9 nmol O2·min−1·mg protein−1, respectively, with the NADH-linked substrate pyruvate and by 7.5 ± 1.4 and 11.6 ± 2.9 nmol O2·min−1·mg protein−1, respectively, with the FADH2-linked substrate succinate (+ rotenone); these effects were abolished by the mtKCa channel blocker paxilline. ΔΨm was not decreased by 10–30 μM NS-1619 with either substrate, but H2O2 release was increased by 44.8% (65.9 ± 2.7% by 30 μM NS-1619 vs. 21.1 ± 3.8% for time controls) with succinate + rotenone. In contrast, NS-1619 did not increase H2O2 release with pyruvate. Similar results were found for lower concentrations of valinomycin. The increase in ROS production in succinate + rotenone-supported mitochondria resulted from a fully maintained ΔΨm, despite increased respiration, a condition that is capable of allowing increased electron leak. We propose that mild matrix K+ influx during states 2 and 4 increases mitochondrial respiration while maintaining ΔΨm; this allows singlet electron uptake by O2 and ROS generation.
Computational approaches for the prediction of protein function in the mitochondrion
Authors: Gabaldón Toni
Published: July 2006

Understanding a complex biological system, such as the mitochondrion, requires the identification of the complete repertoire of proteins targeted to the organelle, the characterization of these, and finally, the elucidation of the functional and physical interactions that occur within the mitochondrion. In the last decade, significant developments have contributed to increase our understanding of the mitochondrion, and among these, computational research has played a significant role. Not only general bioinformatics tools have been applied in the context of the mitochondrion, but also some computational techniques have been specifically developed to address problems that arose from within the mitochondrial research field. In this review the contribution of bioinformatics to mitochondrial biology is addressed through a survey of current computational methods that can be applied to predict which proteins will be localized to the mitochondrion and to unravel their functional interactions.
Angiotensin II cell signaling: physiological and pathological effects in the cardiovascular system
Authors: Mehta Puja K. , Griendling Kathy K.
Published: July 2006

The renin-angiotensin system is a central component of the physiological and pathological responses of cardiovascular system. Its primary effector hormone, angiotensin II (ANG II), not only mediates immediate physiological effects of vasoconstriction and blood pressure regulation, but is also implicated in inflammation, endothelial dysfunction, atherosclerosis, hypertension, and congestive heart failure. The myriad effects of ANG II depend on time (acute vs. chronic) and on the cells/tissues upon which it acts. In addition to inducing G protein- and non-G protein-related signaling pathways, ANG II, via AT1receptors, carries out its functions via MAP kinases (ERK 1/2, JNK, p38MAPK), receptor tyrosine kinases [PDGF, EGFR, insulin receptor], and nonreceptor tyrosine kinases [Src, JAK/STAT, focal adhesion kinase (FAK)]. AT1R-mediated NAD(P)H oxidase activation leads to generation of reactive oxygen species, widely implicated in vascular inflammation and fibrosis. ANG II also promotes the association of scaffolding proteins, such as paxillin, talin, and p130Cas, leading to focal adhesion and extracellular matrix formation. These signaling cascades lead to contraction, smooth muscle cell growth, hypertrophy, and cell migration, events that contribute to normal vascular function, and to disease progression. This review focuses on the structure and function of AT1receptors and the major signaling mechanisms by which angiotensin influences cardiovascular physiology and pathology.
Exercise training reverses downregulation of HSP70 and antioxidant enzymes in porcine skeletal muscle after chronic coronary artery occlusion
Authors: Lawler John M. , Kwak Hyo-Bum , Song Wook , Parker Janet L.
Published: July 2006

Oxidative stress is associated with muscle fatigue and weakness in skeletal muscle of ischemic heart disease patients. Recently, it was found that endurance training elevates protective heat shock proteins (HSPs) and antioxidant enzymes in skeletal muscle in healthy subjects and antioxidant enzymes in heart failure patients. However, it is unknown whether coronary ischemia and mild infarct without heart failure contributes to impairment of stress proteins and whether exercise training reverses those effects. We tested the hypothesis that exercise training would reverse alterations in muscle TNF-α, oxidative stress, HSP70, SOD (Mn-SOD, Cu,Zn-SOD), glutathione peroxidase (GPX), and catalase (CAT) due to chronic coronary occlusion of the left circumflex (CCO). Yucatan swine were divided into three groups ( n = 6 each): sedentary with CCO (SCO); 12 wk of treadmill exercise training following CCO (ECO); and sham surgery controls (sham). Forelimb muscle mass-to-body mass ratio decreased by 27% with SCO but recovered with ECO. Exercise training reduced muscle TNF-α and oxidative stress (4-hydroxynonenal adducts) caused by CCO. HSP70 levels decreased with CCO (−45%), but were higher with exercise training (+348%). Mn-SOD activity, Mn-SOD protein expression, and Cu,Zn-SOD activity levels were higher in ECO than SCO by 72, 82, and 112%, respectively. GPX activity was 177% greater in ECO than in SCO. CAT trended higher ( P = 0.059) in ECO compared with SCO. These data indicate that exercise training following onset of coronary artery occlusion results in recovery of critical stress proteins and reduces oxidative stress.
Spatiotemporal Patterns of an Evoked Network Oscillation in Neocortical Slices: Coupled Local Oscillators
Authors: Bai Li , Huang Xiaoying , Yang Qian , Wu Jian-Young
Published: July 2006

We have discovered an evoked network oscillation in rat neocortical slices and have examined its spatiotemporal patterns with voltage-sensitive dye imaging. The slices (visual and auditory cortices) were prepared in a medium of low calcium, high magnesium and with sodium replaced by choline to reduce the excito-toxicity and sodium loading. After slicing, the choline was washed out while normal calcium, magnesium, and sodium concentrations were restored. The oscillation was evoked by a single electrical shock to slices bathed in normal artificial cerebral spinal fluid (ACSF). The oscillation was organized as an all-or-none epoch containing 4–13 cycles at a central frequency ∼25 Hz. The activity can be reversibly blocked by 6-cyano-7-nitroquinoxalene-2,3-dione (CNQX). 2-amino-5-phosphonopentanoic acid (APV), and atropine but not by bicuculline, indicating polysynaptic excitatory mechanisms. Voltage-sensitive dye imaging showed high-amplitude oscillation signals in superficial and middle cortical layers. Spatiotemporally, the oscillations were organized as waves, propagating horizontally along cortical laminar. Each oscillation cycle was associated with one wave propagating in space. The waveforms were often different at different locations (e.g., extra cycles), suggesting the co-existence of multiple local oscillators. For different cycles, the waves often initiated at different locations, suggesting that local oscillators are competing to initiate each oscillation cycle. Overall our results suggest that this cortical network oscillation is organized at two levels: locally, oscillating neurons are tightly coupled to form local oscillators, and globally the coupling between local oscillators is weak, allowing abrupt spatial phase lags and propagating waves with multiple initiation sites.
Substantial Connections: Water and Identity in an English Cultural Landscape
Authors: Strang Veronica
Published: July 2006

As a material substance, essential to every organic process, water literally constitutes human "being", providing a vital "natural symbol" of sociality and of human-environmental interdependence. Its particular qualities of fluidity and transmutability lend themselves to a stream of metaphors about flows and interconnections, and to ideas about spatio-temporal change and transformation. Moving constantly between internal and external environments, water facilitates scheme transfers between conceptual models of physiological, social and ecological processes. Representing "orderly" flows and balances in each of these, it is vulnerable to pollution at various levels, with concerns about material pollution readily transferred to ideas about social and cultural disorder. In particular, metaphors employing water imagery dominate discourses about individual and cultural identities and the maintenance—or dissolution—of social boundaries.Based on ethnographic research in Dorset, this paper explores these themes and considers how human engagements with water—in the home, and through interaction with rivers and water supply infrastructure—mediate individual, familial and wider collective identities in a shifting cultural " fluidscape" of social, spatial, economic and political relationships. It suggests that, in a post-modern social milieu, images of water and identity vie with more grounded metaphors of landscape, place and location, assisting debates about the potential for fluidity in human constructions of identity.
Green and Extreme: Free-Flowing Through Seascape and Sewer
Authors: Laviolette Patrick
Published: July 2006

Activities to do with the coastline and the aquatic environment such as fishing, boating and seaside holidays have been mainstays of the Cornish peninsula for generations. Building on this legacy of marine leisure, this paper explores both the fluidity and materiality of waves, tides and coastal seascapes through a metaphorical framework encompassing symbolic as well as literal issues of pollution and embodiment. It examines Cornwall's distinct surf culture with regard to concerns over the effects of sewage and other malignant discharges on public health and the quality of the seashore environment. Extreme water sports are an increasingly prominent factor in the formulation of Cornish identity. Hence, the paper outlines the ways in which certain environmental pressure groups, charity campaigners and corporate surf companies have become involved in attempts to safeguard the ecological sustainability of coastal leisure pursuits. It does so primarily through ethnographic case studies concerning Surfers Against Sewage, protest-art exhibitions and environmental campaigns. On the surface, the symbolism of fluidity and pollution may appear contradictory. But through an exploration of the materiality of waves, this paper illustrates the dialectical ways in which water and the sea relate to shifting local identities and to creative forms of extreme subversion.
Ultrasonographic Investigation of the Achilles Tendon in Elite Badminton Players Using Color Doppler
Authors: Boesen Morten Ilum , Boesen Anders , Koenig Merete Juhl , Bliddal Henning , Torp-Pedersen Soren
Published: July 2006

Background

The most frequent injuries in badminton players are in the lower extremities, especially in the Achilles tendon.

Hypothesis

The game of badminton may be related to abnormal intratendinous flow in the Achilles tendon as detected by color Doppler ultrasound. To a certain extent, this blood flow might be physiological, especially when examined after match.

Study Design

Cohort study (prevalence); Level of evidence, 3.

Methods

Seventy-two elite badminton players were interviewed regarding Achilles tendon pain (achillodynia) in the preceding 3 years. Color Doppler was used to examine the tendons of 64 players before their matches and 46 players after their matches. Intratendinous color Doppler flow was graded from 0 to 4. The Achilles tendon was divided into dominant (eg, right side for right-handed players and vice versa) and nondominant side and classified as midtendon, preinsertional, and calcaneal areas.

Results

Of 72 players, 26 had experienced achillodynia in 34 tendons, 18 on the dominant side and 16 on the nondominant side. In 62% of the players with achillodynia, the problems had begun slowly, and the median duration of symptoms was 4 months (range, 0-36 months). Thirty-five percent had ongoing pain in their tendons for a median duration of 12 months (range, 0-12 months). Achillodynia was not associated with the self-reported training load or with sex, age, weight, singles or doubles players, or racket side. Forty-six players were scanned before and after match. At baseline, color Doppler flow was present in the majority of players, and only 7 (16%) players had no color Doppler flow in either tendon. After match, all players had some color Doppler flow in 1 or both tendons. Achillodynia and color Doppler flow were related in the nondominant Achilles tendon (chi-square, P =. 008). The grades of Doppler flow also increased significantly after match in the preinsertional area in both the nondominant (P =. 0002) and dominant (P =. 005) side tendons.

Conclusion

A large proportion of the players had experienced achillodynia and habitually played with a degree of pain that demanded medication. The self-reported pain was associated with increased intratendinous color Doppler flow in the nondominant Achilles tendon. Doppler flow was found in most players before and in all players after the match and therefore may in part be a physiological response to activity.
‘The outsider within’: dilemmas of qualitative feminist research within a culture of resistance
Authors: Watts Jacqueline
Published: July 2006

Feminist research practice is firmly established within the academy and is concerned to develop ways of understanding reality that place women at their centre. However, researching women who do not identify with feminist aims presents feminist researchers with particular challenges in relation to appropriate method and ethical practice. This article discusses these challenges focusing on the issues of ‘gatekeeper’ access, informed consent and the impact that the insider researcher role has on ‘truth telling’. Ideas offered are a critical reflection on qualitative research undertaken into the career experiences of women civil engineers in the UK. The extent to which the inside knowledge of the researcher gives rise to shared understandings and a ‘common’ language, and the ways this creates empathy across a ‘political’ and theoretical divide are discussed. An ethics of care model of feminist research practice that suggests that the line between empathy and exploitation is, in reality, a fine one, is considered. This article argues that researcher integrity is complex and dynamic; it functions along a continuum of practical constraint that involves mutuality, negotiation and re-negotiation of boundaries with participants.
Bicomponent Hollow Fibers for Pervaporation
Authors: Aneja Arun P.
Published: July 2006

Fiber and textile scientists have made great strides in the formation of single and multihole hollow fibers which are of significant practical value to separation science. Pervaporation through bicomponent/composite hollow fibers represents a major potential for the separation of organic and aqueous-organic mixtures. By appropriate selection of the exposed membrane, high throughputs at high selectivities with good chemical and physical stability may be achieved. The article analyzes the transport of isopentane through a composite of silicone rubber and polysulfone asymmetrical hollow fiber membrane. A one parameter mathematical model of the pervaporation process is developed. The parameter is related to the sorption and transport properties of the penetrant through the membrane layers. Pervaporation parameter is a useful tool for membrane characterization and process design.
Evaluation of Commercial Flame Retardant Polyester Curtain Fabrics in the Cone Calorimeter
Authors: Kotresh T. M. , Indushekar R. , Subbulakshmi M. S. , Vijayalakshmi S. N. , Prasad A. S.Krishna , Agrawal A. K.
Published: July 2006

The burning behavior of commercial flame retardant (FR) polyester curtain fabric samples with varying weights in the range of 300–550 g/m2 is investigated using cone calorimetry. The weight of the fabric per unit area is found to influence the peak heat release rate, rate of heat release (RHR), smoke release, and other parameters. Oxygen consumption by the burning fabric needs to be given due importance while selecting the curtain fabrics for application inside the closed interiors.
Role of Fabric Structure on Moisture Retention and its Effect on Concrete Strength
Authors: Mukhopadhyay Samrat , Kumar S. Prem , Venkatesh Babu D. L.
Published: July 2006

This work aims at studying the effect of textile structures on the water retentivity and implications of retentive structures on civil applications. Different structures are analyzed for their water retentivity and drying rate at different conditions of relative humidity (RH) and temperature. Non-woven structures are, in general, more retentive than the woven, under different conditions of test. The possible mechanism behind such a behavior is proposed. Investigations have been carried out on the effect of fabric structure on compressive strength of concrete wrapped and unwrapped with different textile structures by immersing in water for 10 min in an interval of 24 and 48 h. The results show that the concrete wrapped with non-woven fabric gives strength improvement of 2.5 N/mm2 higher than that of woven fabric of the same gram per square meter (GSM) when water is sprayed every day and 1.75 N/mm2 higher when water is sprayed on an alternate day curing cycle.