bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative Proteomic Analyses of Influenza Virus-Infected Cultured Human Lung Cells
Authors: Coombs Kevin M. , Berard Alicia , Xu Wanhong , Krokhin Oleg , Meng Xiaobo , Cortens John P. , Kobasa Darwyn , Wilkins John , Brown Earl G.
Published: August 2010

Because they are obligate intracellular parasites, all viruses are exclusively and intimately dependent upon host cells for replication. Viruses, in turn, induce profound changes within cells, including apoptosis, morphological changes, and activation of signaling pathways. Many of these alterations have been analyzed by gene arrays, which measure the cellular “transcriptome.” Until recently, it has not been possible to extend comparable types of studies to globally examine all the host cellular proteins, which are the actual effector molecules. We have used stable isotope labeling by amino acids in cell culture (SILAC), combined with high-throughput two-dimensional (2-D) high-performance liquid chromatography (HPLC)/mass spectrometry, to determine quantitative differences in host proteins after infection of human lung A549 cells with human influenza virus A/PR/8/34 (H1N1) for 24 h. Of the 4,689 identified and measured cytosolic protein pairs, 127 were significantly upregulated at >95% confidence, 153 were significantly downregulated at >95% confidence, and a total of 87 proteins were upregulated or downregulated more than 5-fold at >99% confidence. Gene ontology and pathway analyses indicated differentially regulated proteins and included those involved in host cell immunity and antigen presentation, cell adhesion, metabolism, protein function, signal transduction, and transcription pathways.
MicroRNA 203 Expression in Keratinocytes Is Dependent on Regulation of p53 Levels by E6
Authors: McKenna Declan J. , McDade Simon S. , Patel Daksha , McCance Dennis J.
Published: August 2010

A screen of microRNA (miRNA) expression following differentiation in human foreskin keratinocytes (HFKs) identified changes in several miRNAs, including miRNA 203 (miR-203), which has previously been shown to play an important role in epithelial cell biology by regulating p63 levels. We investigated how expression of human papillomavirus type 16 (HPV16) oncoproteins E6 and E7 affected miR-203 expression during proliferation and differentiation of HFKs. We demonstrated that miR-203 expression is reduced in HFKs where p53 function is compromised, either by the viral oncoprotein E6 or by knockout of p53 using short hairpin RNAs (p53i). We show that the induction of miR-203 observed during calcium-induced differentiation of HFKs is significantly reduced in HFKs expressing E6 and in p53i HFKs. Induction of miR-203 in response to DNA damage is also reduced in the absence of p53. We report that proliferation of HFKs is dependent on the level of miR-203 expression and that overexpression of miR-203 can reduce overproliferation in E6/E7-expressing and p53i HFKs. In summary, these results indicate that expression of miR-203 is dependent on p53, which may explain how expression of HPV16 E6 can disrupt the balance between proliferation and differentiation, as well as the response to DNA damage, in keratinocytes.
Strain-Specific Differences in the Impact of Human TRIM5α, Different TRIM5α Alleles, and the Inhibition of Capsid-Cyclophilin A Interactions on the Infectivity of HIV-1
Authors: Battivelli Emilie , Lecossier Denise , Matsuoka Saori , Migraine Julie , Clavel François , Hance Allan J.
Published: August 2010

HIV-1 infectivity is strongly restricted by TRIM5α from certain primate species but has been described as being only marginally susceptible to human TRIM5α. In this study, we evaluated the effects of the modulation of human TRIM5α activity (pretreatment of target cells with alpha interferon, expression of a pre-miRNA targeting TRIM5α, and/or overexpression of TRIM5γ), the inhibition of cyclophilin A (CypA)-CA interactions, and the expression of different allelic variants of human TRIM5α on the infectivity of a series of recombinant viruses carrying different patient-derived Gag-protease sequences. We show that HIV-1 displays virus-specific differences in its sensitivity to human TRIM5α and in its sensitivity to different TRIM5α alleles. The effect of inhibiting CypA-CA interactions is also strain specific, and blocking these interactions can either inhibit or improve viral infectivity, depending on the isolate studied. The inhibition of CypA-CA interactions also modulates viral sensitivity to human TRIM5α. In the absence of CypA-CA interactions, most viruses displayed increased sensitivity to the inhibitory effects of TRIM5α on viral replication, but one isolate showed a paradoxical decrease in sensitivity to TRIM5α. Taken together, these findings support a model in which three interlinked factors—capsid sequence, CypA levels, and TRIM5α—interact to determine capsid stability and therefore viral infectivity.
Evidence for a New Avian Paramyxovirus Serotype 10 Detected in Rockhopper Penguins from the Falkland Islands
Authors: Miller Patti J. , Afonso Claudio L. , Spackman Erica , Scott Melissa A. , Pedersen Janice C. , Senne Dennis A. , Brown Justin D. , Fuller Chad M. , Uhart Marcela M. , Karesh William B. , Brown Ian H. , Alexander Dennis J. , Swayne David E.
Published: August 2010

The biological, serological, and genomic characterization of a paramyxovirus recently isolated from rockhopper penguins (
Eudyptes chrysocome
) suggested that this virus represented a new avian paramyxovirus (APMV) group, APMV10. This penguin virus resembled other APMVs by electron microscopy; however, its viral hemagglutination (HA) activity was not inhibited by antisera against any of the nine defined APMV serotypes. In addition, antiserum generated against this penguin virus did not inhibit the HA of representative viruses of the other APMV serotypes. Sequence data produced using random priming methods revealed a genomic structure typical of APMV. Phylogenetic evaluation of coding regions revealed that amino acid sequences of all six proteins were most closely related to APMV2 and APMV8. The calculation of evolutionary distances among proteins and distances at the nucleotide level confirmed that APMV2, APMV8, and the penguin virus all were sufficiently divergent from each other to be considered different serotypes. We propose that this isolate, named APMV10/penguin/Falkland Islands/324/2007, be the prototype virus for APMV10. Because of the known problems associated with serology, such as antiserum cross-reactivity and one-way immunogenicity, in addition to the reliance on the immune response to a single protein, the hemagglutinin-neuraminidase, as the sole base for viral classification, we suggest the need for new classification guidelines that incorporate genome sequence comparisons.
Envelope-Modified Single-Cycle Simian Immunodeficiency Virus Selectively Enhances Antibody Responses and Partially Protects against Repeated, Low-Dose Vaginal Challenge
Authors: Alpert Michael D. , Rahmberg Andrew R. , Neidermyer William , Ng Sharon K. , Carville Angela , Camp Jeremy V. , Wilson Robert L. , Piatak Michael , Mansfield Keith G. , Li Wenjun , Miller Christopher J. , Lifson Jeffrey D. , Kozlowski Pamela A. , Evans David T.
Published: August 2010

Immunization of rhesus macaques with strains of simian immunodeficiency virus (SIV) that are limited to a single cycle of infection elicits T-cell responses to multiple viral gene products and antibodies capable of neutralizing lab-adapted SIV, but not neutralization-resistant primary isolates of SIV. In an effort to improve upon the antibody responses, we immunized rhesus macaques with three strains of single-cycle SIV (scSIV) that express envelope glycoproteins modified to lack structural features thought to interfere with the development of neutralizing antibodies. These envelope-modified strains of scSIV lacked either five potential N-linked glycosylation sites in gp120, three potential N-linked glycosylation sites in gp41, or 100 amino acids in the V1V2 region of gp120. Three doses consisting of a mixture of the three envelope-modified strains of scSIV were administered on weeks 0, 6, and 12, followed by two booster inoculations with vesicular stomatitis virus (VSV) G
trans
-complemented scSIV on weeks 18 and 24. Although this immunization regimen did not elicit antibodies capable of detectably neutralizing SIV
mac
239 or SIV
mac
251
UCD
, neutralizing antibody titers to the envelope-modified strains were selectively enhanced. Virus-specific antibodies and T cells were observed in the vaginal mucosa. After 20 weeks of repeated, low-dose vaginal challenge with SIV
mac
251
UCD
, six of eight immunized animals versus six of six naïve controls became infected. Although immunization did not significantly reduce the likelihood of acquiring immunodeficiency virus infection, statistically significant reductions in peak and set point viral loads were observed in the immunized animals relative to the naïve control animals.
Viral Cell Death Inhibitor MC159 Enhances Innate Immunity against Vaccinia Virus Infection
Authors: Challa Sreerupa , Woelfel Melissa , Guildford Melissa , Moquin David , Chan Francis Ka-Ming
Published: August 2010

Viral inhibitors of host programmed cell death (PCD) are widely believed to promote viral replication by preventing or delaying host cell death. Viral FLIPs (Fas-linked ICE-like protease [FLICE; caspase-8]-like inhibitor proteins) are potent inhibitors of death receptor-induced apoptosis and programmed necrosis. Surprisingly, transgenic expression of the viral FLIP MC159 from molluscum contagiosum virus (MCV) in mice enhanced rather than inhibited the innate immune control of vaccinia virus (VV) replication. This effect of MC159 was specifically manifested in peripheral tissues such as the visceral fat pad, but not in the spleen. VV-infected MC159 transgenic mice mounted an enhanced innate inflammatory reaction characterized by increased expression of the chemokine CCL-2/MCP-1 and infiltration of γδ T cells into peripheral tissues. Radiation chimeras revealed that MC159 expression in the parenchyma, but not in the hematopoietic compartment, is responsible for the enhanced innate inflammatory responses. The increased inflammation in peripheral tissues was not due to resistance of lymphocytes to cell death. Rather, we found that MC159 facilitated Toll-like receptor 4 (TLR4)- and tumor necrosis factor (TNF)-induced NF-κB activation. The increased NF-κB responses were mediated in part through increased binding of RIP1 to TNFRSF1A-associated via death domain (TRADD), two crucial signal adaptors for NF-κB activation. These results show that MC159 is a dual-function immune modulator that regulates host cell death as well as NF-κB responses by innate immune signaling receptors.
Papillomavirus Infection Requires γ Secretase
Authors: Karanam Balasubramanyam , Peng Shiwen , Li Tong , Buck Christopher , Day Patricia M. , Roden Richard B. S.
Published: August 2010

The mechanism by which papillomaviruses breach cellular membranes to deliver their genomic cargo to the nucleus is poorly understood. Here, we show that infection by a broad range of papillomavirus types requires the intramembrane protease γ secretase. The γ-secretase inhibitor (
S
,
S
)-2-[2-(3,5-difluorophenyl)-acetylamino]-
N
-(1-methyl-2-oxo-5-phenyl-2,3-dihydro-1H-benzo[e][1,4]diazepin-3-yl)-propionamide (compound XXI) inhibits infection
in vitro
by all types of papillomavirus pseudovirions tested, with a 50% inhibitory concentration (IC
50
) of 130 to 1,000 pM, regardless of reporter construct and without impacting cellular viability. Conversely, XXI does not inhibit
in vitro
infection by adenovirus or pseudovirions derived from the BK or Merkel cell polyomaviruses. Vaginal application of XXI prevents infection of the mouse genital tract by human papillomavirus type 16 (HPV16) pseudovirions. Nicastrin and presenilin-1 are essential components of the γ-secretase complex, and mouse embryo fibroblasts deficient in any one of these components were not infected by HPV16, whereas wild-type and β-secretase (BACE1)-deficient cells were susceptible. Neither the uptake of HPV16 into Lamp-1-positive perinuclear vesicles nor the disassembly of capsid to reveal both internal L1 and L2 epitopes and bromodeoxyuridine (BrdU)-labeled encapsidated DNA is dependent upon γ-secretase activity. However, blockade of γ-secretase activity by XXI prevents the BrdU-labeled DNA encapsidated by HPV16 from reaching the ND10 subnuclear domains. Since prior studies indicate that L2 is critical for endosomal escape and targeting of the viral DNA to ND10 and that γ secretase is located in endosomal membranes, our findings suggest that either L2 or an intracellular receptor are cleaved by γ secretase as papillomavirus escapes the endosome.
A Maraviroc-Resistant HIV-1 with Narrow Cross-Resistance to Other CCR5 Antagonists Depends on both N-Terminal and Extracellular Loop Domains of Drug-Bound CCR5
Authors: Tilton John C. , Wilen Craig B. , Didigu Chukwuka A. , Sinha Rohini , Harrison Jessamina E. , Agrawal-Gamse Caroline , Henning Elizabeth A. , Bushman Frederick D. , Martin Jeffrey N. , Deeks Steven G. , Doms Robert W.
Published: August 2010

CCR5 antagonists inhibit HIV entry by binding to a coreceptor and inducing changes in the extracellular loops (ECLs) of CCR5. In this study, we analyzed viruses from 11 treatment-experienced patients who experienced virologic failure on treatment regimens containing the CCR5 antagonist maraviroc (MVC). Viruses from one patient developed high-level resistance to MVC during the course of treatment. Although resistance to one CCR5 antagonist is often associated with broad cross-resistance to other agents, these viruses remained sensitive to most other CCR5 antagonists, including vicriviroc and aplaviroc. MVC resistance was dependent upon mutations within the V3 loop of the viral envelope (Env) protein and was modulated by additional mutations in the V4 loop. Deep sequencing of pretreatment plasma viral RNA indicated that resistance appears to have occurred by evolution of drug-bound CCR5 use, despite the presence of viral sequences predictive of CXCR4 use. Envs obtained from this patient before and during MVC treatment were able to infect cells expressing very low CCR5 levels, indicating highly efficient use of a coreceptor. In contrast to previous reports in which CCR5 antagonist-resistant viruses interact predominantly with the N terminus of CCR5, these MVC-resistant Envs were also dependent upon the drug-modified ECLs of CCR5 for entry. Our results suggest a model of CCR5 cross-resistance whereby viruses that predominantly utilize the N terminus are broadly cross-resistant to multiple CCR5 antagonists, whereas viruses that require both the N terminus and antagonist-specific ECL changes demonstrate a narrow cross-resistance profile.
Antibody 2G12 Recognizes Di-Mannose Equivalently in Domain- and Nondomain-Exchanged Forms but Only Binds the HIV-1 Glycan Shield if Domain Exchanged
Authors: Doores Katie J. , Fulton Zara , Huber Michael , Wilson Ian A. , Burton Dennis R.
Published: August 2010

The broadly neutralizing anti-human immunodeficiency virus type 1 (HIV-1) antibody 2G12 targets the high-mannose cluster on the glycan shield of HIV-1. 2G12 has a unique VHdomain-exchanged structure, with a multivalent binding surface that includes two primary glycan binding sites. The high-mannose cluster is an attractive target for HIV-1 vaccine design, but so far, no carbohydrate immunogen has elicited 2G12-like antibodies. Important questions remain as to how this domain exchange arose in 2G12 and how this unusual event conferred unexpected reactivity against the glycan shield of HIV-1. In order to address these questions, we generated a nondomain-exchanged variant of 2G12 to produce a conventional Y/T-shaped antibody through a single amino acid substitution (2G12 I19R) and showed that, as for the 2G12 wild type (2G12 WT), this antibody is able to recognize the same Manα1,2Man motif on recombinant gp120,Candida albicans, and synthetic glycoconjugates. However, the nondomain-exchanged variant of 2G12 is unable to bind the cluster of mannose moieties on the surface of HIV-1. Crystallographic analysis of 2G12 I19R in complex with Manα1,2Man revealed an adaptable hinge between VHand CH1 that enables the VHand VLdomains to assemble in such a way that the configuration of the primary binding site and its interaction with disaccharide are remarkably similar in the nondomain-exchanged and domain-exchanged forms. Together with data that suggest that very few substitutions are required for domain exchange, the results suggest potential mechanisms for the evolution of domain-exchanged antibodies and immunization strategies for eliciting such antibodies.
Structural and Functional Characterization of an Influenza Virus RNA Polymerase-Genomic RNA Complex
Authors: Resa-Infante Patricia , Recuero-Checa María Ángeles , Zamarreño Noelia , Llorca Óscar , Ortín Juan
Published: August 2010

The replication and transcription of influenza A virus are carried out by ribonucleoproteins (RNPs) containing each genomic RNA segment associated with nucleoprotein monomers and the heterotrimeric polymerase complex. These RNPs are responsible for virus transcription and replication in the infected cell nucleus. Here we have expressed, purified, and analyzed, structurally and functionally, for the first time, polymerase-RNA template complexes obtained after replication
in vivo
. These complexes were generated by the cotransfection of plasmids expressing the polymerase subunits and a genomic plasmid expressing a minimal template of positive or negative polarity. Their generation
in vivo
was strictly dependent on the polymerase activity; they contained mainly negative-polarity viral RNA (vRNA) and could transcribe and replicate
in vitro
. The three-dimensional structure of the monomeric polymerase-vRNA complexes was similar to that of the RNP-associated polymerase and distinct from that of the polymerase devoid of template. These results suggest that the interaction with the template is sufficient to induce a significant conformation switch in the polymerase complex.
Structure of
Penaeus stylirostris
Densovirus, a Shrimp Pathogen
Authors: Kaufmann Bärbel , Bowman Valorie D. , Li Yi , Szelei Jozsef , Waddell Peter J. , Tijssen Peter , Rossmann Michael G.
Published: August 2010

Penaeus stylirostris
densovirus (
Pst
DNV), a pathogen of penaeid shrimp, causes significant damage to farmed and wild shrimp populations. In contrast to other parvoviruses,
Pst
DNV probably has only one type of capsid protein that lacks the phospholipase A2 activity that has been implicated as a requirement during parvoviral host cell infection. The structure of recombinant virus-like particles, composed of 60 copies of the 37.5-kDa coat protein, the smallest parvoviral capsid protein reported thus far, was determined to 2.5-Å resolution by X-ray crystallography. The structure represents the first near-atomic resolution structure within the genus
Brevidensovirus
. The capsid protein has a β-barrel “jelly roll” motif similar to that found in many icosahedral viruses, including other parvoviruses. The N-terminal portion of the
Pst
DNV coat protein adopts a “domain-swapped” conformation relative to its twofold-related neighbor similar to the insect parvovirus
Galleria mellonella
densovirus (
Gm
DNV) but in stark contrast to vertebrate parvoviruses. However, most of the surface loops have little structural resemblance to any of the known parvoviral capsid proteins.
Primary Human Mammary Epithelial Cells Endocytose HIV-1 and Facilitate Viral Infection of CD4
+
T Lymphocytes
Authors: Dorosko Stephanie M. , Connor Ruth I.
Published: August 2010

The contribution of mammary epithelial cells (MEC) to human immunodeficiency virus type 1 (HIV-1) in breast milk remains largely unknown. While breast milk contains CD4
+
cells throughout the breast-feeding period, it is not known whether MEC directly support HIV-1 infection or facilitate infection of CD4
+
cells in the breast compartment. This study evaluated primary human MEC for direct infection with HIV-1 and for indirect transfer of infection to CD4
+
target cells. Primary human MEC were isolated and assessed for expression of HIV-1 receptors. MEC were exposed to CCR5-, CXCR4- and dual-tropic strains of HIV-1 and evaluated for viral reverse transcription and integration and productive viral infection. MEC were also tested for the ability to transfer HIV to CD4
+
target cells and to activate resting CD4
+
T cells. Our results demonstrate that MEC express HIV-1 receptor proteins CD4, CCR5, CXCR4, and galactosyl ceramide (GalCer). While no evidence for direct infection of MEC was found, HIV-1 virions were observed in MEC endosomal compartments. Coculture of HIV-exposed MEC resulted in productive infection of activated CD4
+
T cells. In addition, MEC secretions increased HIV-1 replication and proliferation of infected target cells. Overall, our results indicate that MEC are capable of endosomal uptake of HIV-1 and can facilitate virus infection and replication in CD4
+
target cells. These findings suggest that MEC may serve as a viral reservoir for HIV-1 and may enhance infection of CD4
+
T lymphocytes
in vivo
.
The ESEV PDZ-Binding Motif of the Avian Influenza A Virus NS1 Protein Protects Infected Cells from Apoptosis by Directly Targeting Scribble
Authors: Liu Hongbing , Golebiewski Lisa , Dow Eugene C. , Krug Robert M. , Javier Ronald T. , Rice Andrew P.
Published: August 2010

The NS1 protein from influenza A viruses contains a four-amino-acid sequence at its carboxyl terminus that is termed the PDZ-binding motif (PBM). The NS1 PBM is predicted to bind to cellular PDZ proteins and functions as a virulence determinant in infected mice. ESEV is the consensus PBM sequence of avian influenza viruses, while RSKV is the consensus sequence of human viruses. Currently circulating highly pathogenic H5N1 influenza viruses encode an NS1 protein with the ESEV PBM. We identified cellular targets of the avian ESEV PBM and identified molecular mechanisms involved in its function. Using glutathione
S
-transferase (GST) pull-down assays, we found that the ESEV PBM enables NS1 to associate with the PDZ proteins Scribble, Dlg1, MAGI-1, MAGI-2, and MAGI-3. Because Scribble possesses a proapoptotic activity, we investigated the interaction between NS1 and Scribble. The association between NS1 and Scribble is direct and requires the ESEV PBM and two Scribble PDZ domains. We constructed recombinant H3N2 viruses that encode an H6N6 avian virus NS1 protein with either an ESEV or mutant ESEA PBM, allowing an analysis of the ESEV PBM in infections in mammalian cells. The ESEV PBM enhanced viral replication up to 4-fold. In infected cells, NS1 with the ESEV PBM relocalized Scribble into cytoplasmic puncta concentrated in perinuclear regions and also protected cells from apoptosis. In addition, the latter effect was eliminated by small interfering RNA (siRNA)-mediated Scribble depletion. This study shows that one function of the avian ESEV PBM is to reduce apoptosis during infection through disruption of Scribble's proapoptotic function.
Resistance to Rabies Virus Infection Conferred by the PMLIV Isoform
Authors: Blondel Danielle , Kheddache Sabrina , Lahaye Xavier , Dianoux Laurent , Chelbi-Alix Mounira K.
Published: August 2010

Various reports implicate PML and PML nuclear bodies (NBs) in an intrinsic antiviral response targeting diverse cytoplasmic replicating RNA viruses. PML conjugation to the small ubiquitin-like modifier (SUMO) is required for its localization within NBs. PML displays antiviral effects
in vivo
, as PML deficiency renders mice more susceptible to infection with the rhabdovirus vesicular stomatitis virus (VSV). Cells derived from these mice are also more sensitive to infection with rabies virus, another member of the rhabdovirus family. Alternative splicing from a single gene results in the synthesis of several PML isoforms, and these are classified into seven groups, designated PMLI to -VII. We report here that expression of PMLIV or PMLIVa, which is missing exon 5, inhibited viral mRNA and protein synthesis, leading to a reduction in viral replication. However, the expression of other nuclear isoforms (PMLI to -VI) and cytoplasmic PMLVIIb failed to impair viral production. This antiviral effect required PMLIV SUMOylation, as it was not observed with PMLIV 3KR, in which the lysines involved in SUMO conjugation were mutated. Thus, PMLIV and PMLIVa may exert this isoform-specific function through interaction with specific NB protein partners via their common C-terminal region.
Nuclear Factor NF45 Interacts with Viral Proteins of Infectious Bursal Disease Virus and Inhibits Viral Replication
Authors: Stricker Ruth L. O. , Behrens Sven-Erik , Mundt Egbert
Published: August 2010

Two of the central issues in developing new strategies to interfere with viral infections concern the identification of cellular proteins involved in viral replication and/or antiviral measures and the dissection of the underlying molecular mechanisms. To gain initial insight into the role of host proteins in the life cycle of infectious bursal disease virus (IBDV), a double-stranded RNA virus, we examined the cellular nuclear factor 45 (NF45). NF45 was previously indicated to be involved in the replication process of other types of RNA viruses. Interestingly, by performing immunofluorescence studies, we found that in IBDV-infected cells the mainly nuclear NF45 accumulated at the sites of viral replication in the cytoplasm. NF45 was shown to specifically colocalize with the viral RNA-dependent RNA polymerase VP1, the capsid protein VP2, and the ribonucleoprotein VP3. Immunoprecipitation experiments indicated protein-protein associations between NF45 and VP1, VP2, and VP3. Expression of the individual VP3 or the combination of expression of VP1 and VP3 did not result in a cytoplasmic accumulation of NF45, which, among other data, showed that recruitment of the cellular protein in infected cells functionally correlates with the viral replication process. Since small interfering RNA(siRNA)-mediated downregulation of NF45 resulted in an approximately 5-fold increase of virus yield, our study suggests that NF45, by association with viral proteins, is part of a yet-uncharacterized cellular defense mechanism against IBDV infections.
Macropolyhedral boron-containing cluster chemistry [S2B16H17]–. A new eighteen-vertex thiaborane anion
Authors: Carr Michael J. , Clegg William , Kennedy John D. , Londesborough Michael G. S. , Kilner Colin A.
Published: August 2010

The novel eighteen-vertex macropolyhedral dithiaborane anion [S2B16H17]– 1 has been obtained as its [tmndH]+ salt from the reaction of [S2B17H17] 2 and tmnd in solution in the presence of [RhCl2(η5-C5Me5)]2. It has two cluster skeletal electrons more than the three previously reported eighteen-vertex dithiaborane {S2B16} species n-[S2B16H16], n-[S2B16H15]– and iso-[S2B16H16], and the anion consists structurally of an arachno {SB9} and a nido {B9} cluster unit fused with two boron atoms in common, and with an endo-to-exo sulfur bridge that also links the two subclusters together.
Understanding the experiences of allergy testing: a qualitative study of people with perceived serious allergic disorders
Authors: Burton Christopher , Irshad Tasneem , Sheikh Aziz
Published: August 2010

Purpose

To investigate the experience of patients with perceived severe allergic disorders in obtaining allergen testing.

Design

In-depth interviews with 20 purposively sampled adults and parents of children with, or at perceived risk of, serious allergic problems. Data were analysed thematically, drawing on Frank’s classification of narratives to help interpret patient/carer accounts.

Results

Accounts fell into four main groups: (i) children with anaphylaxis occurring ‘out of the blue’ (ii) children in whom the recognition of severe allergy by professionals was perceived as delayed; (iii) adults with anaphylaxis who adapted; and (iv) adults who remained in search of an answer. Whereas children had eventually been assessed and tested in a specialist clinic, adults had difficulty in obtaining testing, and most—including those for whom current guidelines would recommend testing—had not been tested. Participants incorporated their past experience of testing into narrative accounts, which included current ways of dealing with their allergy. They saw testing as only one component of appropriate allergy management which required interpretive expertise in professionals who ordered tests. Despite the limitations in NHS allergy testing provision, there was relatively little interest among patients/carers in using complementary and alternative providers of allergy testing.

Conclusions

Patients perceived major shortfalls in relation to NHS allergy testing provision, focusing on both the availability of testing and expertise in interpreting the results. Any increased provision of testing needs to be matched by access to specialist interpretation of these tests.
THE WARPING DEGREE OF A KNOT DIAGRAM
Authors: SHIMIZU AYAKA
Published: August 2010

For an oriented knot diagram D, the warping degree d(D) is the smallest number of crossing changes which are needed to obtain the monotone diagram from D in the usual way. We show that d(D) + d(-D) + 1 is less than or equal to the crossing number of D. Moreover, the equality holds if and only if D is an alternating diagram. For a knot K, we also estimate the minimum of d(D) + d(-D) for all diagrams D of K with c(D) = c(K).
VIRTUAL HOMOTOPY
Authors: DYE H. A. , KAUFFMAN LOUIS H.
Published: August 2010

Two welded (respectively virtual) link diagrams are homotopic if one may be transformed into the other by a sequence of extended Reidemeister moves, classical Reidemeister moves, and self crossing changes. In this paper, we extend Milnor's μ and [Formula: see text] invariants to welded and virtual links. We conclude this paper with several examples, and compute the μ invariants using the Magnus expansion and Polyak's skein relation for the μ invariants.
REGULAR PROJECTIONS OF GRAPHS WITH AT MOST THREE DOUBLE POINTS
Authors: HUH YOUNGSIK , NIKKUNI RYO
Published: August 2010

A generic immersion of a planar graph into the 2-space is said to be knotted if there does not exist a trivial embedding of the graph into the 3-space obtained by lifting the immersion with respect to the natural projection from the 3-space to the 2-space. In this paper, we show that if a generic immersion of a planar graph is knotted then the number of double points of the immersion is more than or equal to three. To prove this, we also show that an embedding of a graph obtained from a generic immersion of the graph (does not need to be planar) with at most three double points is totally free if it contains neither a Hopf link nor a trefoil knot.
THE MAPPING CLASS GROUP OF (S3, K), WHERE K IS A TWO-BRIDGE KNOT OR LINK
Authors: JEEVANJEE THERESA
Published: August 2010

Let K be a two-bridge knot or link in S3. Then K is also denoted as the four-plat, b(p, q) to indicate its association with some rational number p/q. The lens space L = L(p, q) admits an isometry τ of order two, such that the quotient space L modulo the involution τ is an orbifold whose exceptional set is K and whose underlying space is S3. In this paper, the mapping class groups of these orbifolds are classified. While these groups can be found as a result of Mostow's Rigidity Theorem, this paper calculates the generators and relations of the groups and the proof does not rely on this strong theorem for the majority of cases.
DUALITIES AND POSITIVITY IN THE STUDY OF QUANTUM ENTANGLEMENT
Authors: SKOWRONEK ŁUKASZ
Published: August 2010

We present a survey on mathematical topics relating to separable states and entanglement witnesses. The convex cone duality between separable states and entanglement witnesses is discussed and later generalized to other families of operators, leading to their characterization via multiplicative properties. The condition for an operator to be an entanglement witness is rephrased as a problem of positivity of a family of real polynomials. By solving the latter in a specific case of a three-parameter family of operators, we obtain explicit description of entanglement witnesses belonging to that family. A related problem of block positivity over real numbers is discussed. We also consider a broad family of block positivity tests and prove that they can never be sufficient, which should be useful in case of future efforts in that direction. Finally, we introduce the concept of length of a separable state and present new results concerning relationships between the length and Schmidt rank. In particular, we prove that separable states of length lower or equal to 3 have Schmidt ranks equal to their lengths. We also give an example of a state which has length 4 and Schmidt rank 3.
Towards the synthesis of substituted porphyrins by a pyridyl group bearing a reactive functionality
Authors: Ojaimi Maya El , Habermeyer Benoit , Gros Claude P. , Barbe Jean-Michel
Published: August 2010

Pyridyl-substituted porphyrins bearing a reactive functionality were prepared via Suzuki cross-coupling reactions and resulted in very good yields. These compounds are precursors of new porphyrin architectures able to coordinate two metals: one in the porphyrin core and the second around the pyridyl moiety. During the coupling reactions, a higher reactivity of a chloro picolyl group was evidenced compared to a bromo function on the same reacting molecule.
Synthesis and characterization of 1,8(11),15(18),22(25)-tetraglycosylated zinc(II) phthalocyanines
Authors: Iqbal Zafar , Lyubimtsev Alexey , Hanack Michael , Ziegler Thomas
Published: August 2010

In continuation of our work on glycosylated phthalocyanines, a new series of 1,8(11),15(18),22(25)-tetraglycosylated zinc(II) phthalocyanines (PcZns) have been synthesized and characterized. 3-glycosylated phthalonitriles were synthesized through nitrite displacement in 3-nitrophthalonitrile with anomerically deprotected glycoses. The anomerically glycosylated phthalonitriles were then treated with hexamethyldisilazane (HMDS), trimethylsilyltriflate (TMSOTf) and zinc salt in DMF to form the corresponding acetyl-protected PcZns, followed by deprotection of acetyl groups by NaOMe in methanol/DMSO mixture. The formed unprotected tetraglycosylated PcZns are highly soluble in water, which is a necessary condition for potential biological applications.
Syntheses and characterization of a series of oxacalix[4]arene-linked cofacial bisporphyrins
Authors: Jiao Lijuan , Fang Yanhua , Zhou Yunyou , Wang Sufan , Hao Erhong , Vicente M. Graça H.
Published: August 2010

A series of oxacalix[4]arene-linked cofacial bisporphyrins 2–4 have been synthesized as free-bases, biszinc(II) and biscopper(II) complexes. UV-vis, fluorescence and cyclic voltammetric studies were performed on the bisporphyrins. Little electronic interactions between the two porphyrin macrocycles in both the metal-free and biszinc(II) complexes 2 and 3 were observed, while enhanced electronic communications were observed in the case of 4 bearing two copper(II) metal ions. Geometry optimizations were carried out using HF/CEP-31G methods to investigate the molecular structures of these bisporphyrins. Solvent effects on the photophysical properties of these bisporphyrins are also discussed.
Design, synthesis and biological evaluation of folate-porphyrin: a new photosensitizer for targeted photodynamic therapy
Authors: Li Donghong , Diao Junlin , Wang Dong , Liu Jianchang , Zhang Jiaotao
Published: August 2010

A novel folate-porphyrin conjugate 1 for targeted photodynamic therapy of tumor was designed and synthesized. The results of fluorescence spectroscopy and confocal laser scanning microscope demonstrated that the cellular uptake of conjugate 1 by HeLa cells was 35 times higher than that of precursor porphyrin 3 after 24 h incubation, and that the presence of excessive free folic acid inhibited the cellular uptake of conjugate 1. Cytotoxicity against folate-receptor positive HeLa cells in vitro measured by MTT assay demonstrated that conjugate 1 exhibited much lower dark cytotoxicity but significant photocytotoxicity, with 86.4% of cell growth inhibition ratio after irradiation. However, conjugate 1 induced lower photocytotoxicity for normal cells and folate-receptor negative cells. These results suggest that folate-porphyrin like photosensitizers could induce a potentially useful targeted photodynamic therapy modality for folate-receptor-positive cancer cells due to the folate-receptor mediated endocytosis.
Nanoaggregates in floating layers of azaporphyrins
Authors: Valkova Larissa A. , Zyablov Sergei V. , Erokhin Victor V. , Koifman Oscar I.
Published: August 2010

An analysis of compression isotherms of floating layers of copper tetra-tert-butylphthalocyanine ( CuPctBu4 ) and copper tetrabenzotriazaporphyrine, obtained at varied initial conditions, is carried out. The structure of layers is determined by three methods: the traditional one (direct estimation of area per molecule from a π-A isotherm), by a quantitative analysis of compression isotherms (with the use of Volmer equation), and by Brewster angle microscopy. It is shown that in layers with edge-on arrangement of molecules (initial surface concentrations N0 > 0.15 μmol.m-2), the layer structure, determined by the quantitative method, may differ drastically from the structure obtained by the traditional one. The equation of state of the floating layer generalized to the case when structural units of 2D gas are molecular aggregates is used to describe the layer of azaporphyrines. Boundaries of existence and characteristics of structure and properties of floating layers in stable states (size of nanoaggregates formed in a layer, number of molecules in them, interaggregate spacing, compressibility) are determined. The quantitative model of floating layer of copper tetra-tert-butylphthalocyanine is proposed. Constants characterizing a stable monolayer, as well as the region where it may be formed, are determined on the base of the model created.
Cross-species comparison of genomewide gene expression profiles reveals induction of hypoxia-inducible factor-responsive genes in iron-deprived intestinal epithelial cells
Authors: Hu Zihua , Gulec Sukru , Collins James F.
Published: August 2010

Molecular mechanisms mediating the induction of metal ion homeostasis-related genes in the mammalian intestine during iron deficiency remain unknown. To elucidate relevant regulatory pathways, genomewide gene expression profiles were determined in fully differentiated human intestinal epithelial (Caco-2) cells. Cells were deprived of iron (or not) for 6 or 18 h, and Gene Chip analyses were subsequently performed (Affymetrix). More than 2,000 genes were differentially expressed; genes related to monosaccharide metabolism, regulation of gene expression, hypoxia, and cell death were upregulated, while those related to mitotic cell cycle were downregulated. A large proportion of induced genes are hypoxia responsive, and promoter enrichment analyses revealed a statistical overrepresentation of hypoxia response elements (HREs). Immunoblot experiments demonstrated a >60-fold increase in HIF2α protein abundance in iron-deprived cells; HIF1α levels were unchanged. Furthermore, comparison of the Caco-2 cell data set with a Gene Chip data set from iron-deficient rat intestine revealed 29 common upregulated genes; the majority are hypoxia responsive, and their promoters are enriched for HREs. We conclude that the compensatory response of the intestinal epithelium to iron deprivation relates to hypoxia and that stabilization of HIF2α may be the primary event mediating metabolic and morphological changes observed during iron deficiency.
Acute and chronic effects of dietary nitrate supplementation on blood pressure and the physiological responses to moderate-intensity and incremental exercise
Authors: Vanhatalo Anni , Bailey Stephen J. , Blackwell Jamie R. , DiMenna Fred J. , Pavey Toby G. , Wilkerson Daryl P. , Benjamin Nigel , Winyard Paul G. , Jones Andrew M.
Published: August 2010

Dietary nitrate (NO3−) supplementation with beetroot juice (BR) over 4–6 days has been shown to reduce the O2cost of submaximal exercise and to improve exercise tolerance. However, it is not known whether shorter (or longer) periods of supplementation have similar (or greater) effects. We therefore investigated the effects of acute and chronic NO3−supplementation on resting blood pressure (BP) and the physiological responses to moderate-intensity exercise and ramp incremental cycle exercise in eight healthy subjects. Following baseline tests, the subjects were assigned in a balanced crossover design to receive BR (0.5 l/day; 5.2 mmol of NO3−/day) and placebo (PL; 0.5 l/day low-calorie juice cordial) treatments. The exercise protocol (two moderate-intensity step tests followed by a ramp test) was repeated 2.5 h following first ingestion (0.5 liter) and after 5 and 15 days of BR and PL. Plasma nitrite concentration (baseline: 454 ± 81 nM) was significantly elevated (+39% at 2.5 h postingestion; +25% at 5 days; +46% at 15 days; P < 0.05) and systolic and diastolic BP (baseline: 127 ± 6 and 72 ± 5 mmHg, respectively) were reduced by ∼4% throughout the BR supplementation period ( P < 0.05). Compared with PL, the steady-state V̇o2during moderate exercise was reduced by ∼4% after 2.5 h and remained similarly reduced after 5 and 15 days of BR ( P < 0.05). The ramp test peak power and the work rate at the gas exchange threshold (baseline: 322 ± 67 W and 89 ± 15 W, respectively) were elevated after 15 days of BR (331 ± 68 W and 105 ± 28 W; P < 0.05) but not PL (323 ± 68 W and 84 ± 18 W). These results indicate that dietary NO3−supplementation acutely reduces BP and the O2cost of submaximal exercise and that these effects are maintained for at least 15 days if supplementation is continued.
Heme oxygenase activity as a determinant of the renal hemodynamic response to low-dose ANG II
Authors: Nath Karl A. , Hernandez Melissa C. , Croatt Anthony J. , Katusic Zvonimir S. , Juncos Luis A.
Published: August 2010

ANG II causes renal injury through hemodynamic and other effects, and pressor doses of ANG II induce heme oxygenase-1 (HO-1) as a protective response. The present studies examined the hemodynamic effects of more clinically relevant, lower doses of ANG II and the role of HO activity in influencing these effects. Under euvolemic conditions, ANG II increased arterial pressure and renal vascular resistance. ANG II did not induce oxidative stress, inflammation/injury-related gene expression, or proteinuria and did not alter extrarenal vascular reactivity. At these doses, ANG II failed to increase HO-1 or HO-2 mRNA expression or HO activity. Inhibiting HO activity in ANG II-treated rats by tin mesoporphyrin further increased renal vascular resistances, decreased renal blood flow, and blunted the rise in arterial pressure without inducing oxidative stress or altering expression of selected vasoactive/injury/inflammation-related genes; tin mesoporphyrin did not alter vasorelaxation of mesenteric resistor vessels. We conclude that in this model renal vasoconstriction occurs without the recognized adverse effects of ANG II on glomerular filtration rate, renal blood flow, oxidative stress, vascular reactivity, proteinuria, and injury-related gene expression; renal HO activity is essential in preserving perfusion of the ANG II-exposed kidney. These findings represent an uncommon example wherein function of a stressed organ (by ANG II), but not that of the unstressed organ, requires intact renal HO activity, even when the imposed stress neither induces HO-1 nor HO activity. These findings may be germane to conditions attended by heightened ANG II levels, ineffective renal perfusion, and susceptibility to acute kidney injury.
Complement factor 3 deficiency attenuates hemorrhagic shock-related hepatic injury and systemic inflammatory response syndrome
Authors: Cai Changchun , Gill Roop , Eum Hyun-Ae , Cao Zongxian , Loughran Patricia A. , Darwiche Sophie , Edmonds Rebecca D. , Menzel Christoph L. , Billiar Timothy R.
Published: August 2010

Although complement activation is known to occur in the setting of severe hemorrhagic shock and tissue trauma (HS/T), the extent to which complement drives the initial inflammatory response and end-organ damage is uncertain. In this study, complement factor 3-deficient (C3−/−) mice and wild-type control mice were subjected to 1.5-h hemorrhagic shock, bilateral femur fracture, and soft tissue injury, followed by 4.5-h resuscitation (HS/T). C57BL/6 mice were also given 15 U of cobra venom factor (CVF) or phosphate-buffered saline injected intraperitoneally, followed by HS/T 24 h later. The results showed that HS/T resulted in C3 consumption in wild-type mice and C3 deposition in injured livers. C3−/−mice had significantly lower serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and circulating DNA levels, together with much lower circulating interleukin (IL)-6, IL-10, and high-mobility group box 1 (HMGB1) levels. Temporary C3 depletion by CVF preconditioning also led to reduced transaminases and a blunted cytokine release. C3−/−mice displayed well-preserved hepatic structure. C3−/−mice subjected to HS/T had higher levels of heme oxygenase-1, which has been associated with tissue protection in HS models. Our data indicate that complement activation contributes to inflammatory pathways and liver damage in HS/T. This suggests that targeting complement activation in the setting of severe injury could be useful.
Taste does not determine daily intake of dilute sugar solutions in mice
Authors: Glendinning J. I. , Beltran F. , Benton L. , Cheng S. , Gieseke J. , Gillman J. , Spain H. N.
Published: August 2010

When a rodent licks a sweet-tasting solution, taste circuits in the central nervous system that facilitate stimulus identification, motivate intake, and prepare the body for digestion are activated. Here, we asked whether taste also determines daily intake of sugar solutions in C57BL/6 mice. We tested several dilute concentrations of glucose (167, 250, and 333 mM) and fructose (167, 250, and 333 mM). In addition, we tested saccharin (38 mM), alone and in binary mixture with each of the sugar concentrations, to manipulate sweet taste intensity while holding caloric value constant. In experiment 1, we measured taste responsiveness to the sweetener solutions in two ways: chorda tympani nerve responses and short-term lick tests. For both measures, the mice exhibited the following relative magnitude of responsiveness: binary mixtures > saccharin > individual sugars. In experiment 2, we asked whether the taste measures reliably predicted daily intake of the sweetener solutions. No such relationship was observed. The glucose solutions elicited weak taste responses but high daily intakes, whereas the fructose solutions elicited weak taste responses and low daily intakes. On the other hand, the saccharin + glucose solutions elicited strong taste responses and high daily intakes, while the saccharin + fructose solutions elicited strong taste responses but low daily intakes. Overall, we found that 1) daily intake of the sweetener solutions varied independently of the magnitude of the taste responses and 2) the solutions containing glucose stimulated substantially higher daily intakes than did the solutions containing isomolar concentrations of fructose. Given prior work demonstrating greater postoral stimulation of feeding by glucose than fructose, we propose that the magnitude of postoral nutritive stimulation plays a more important role than does taste in determining daily intake of dilute sugar solutions.