bluuebunny/crossref_metadata_2025 huggingface dataset:
Light-addressable electrode with hydrogenated amorphous silicon and low-conductive passivation layer for stimulation of cultured neurons
Authors: Suzurikawa Jun , Takahashi Hirokazu , Kanzaki Ryohei , Nakao Masayuki , Takayama Yuzo , Jimbo Yasuhiko
Published: February 2007

The authors propose a light-addressable planar electrode with a simple three-layer laminated structure that can induce pinpoint neuronal activation on the culture substrate. The structure consists of a tin oxide (SnO2), hydrogenated amorphous silicon (a-Si:H), and passivation layer. The passivation layer was a spin-coated low-conductive zinc antimonate (ZnOSb2O5)-dispersed epoxy, which was proved to be effective for preventing penetration of culture medium and thus avoiding deterioration of a-Si:H layer. Illumination to the electrode locally elevated the conductivity with 60-fold stimulus charge density. The fluo-4 calcium imaging of neurons cultured on the developed electrode showed that the neuronal activation was confined around the illuminated location, thus demonstrating the light-addressing capability of the proposed electrode.
Investigation of electrical contact resistance for nonconductive film functionalized with π-conjugated self-assembled molecules
Authors: Dong Hai , Li Yi , Yim Myung Jin , Moon Kyung Sik , Wong C. P.
Published: February 2007

Nonconductive adhesive/nonconductive film (NCA/NCF) bonding technology has attracted increasing research interests as lead-free interconnect. During bonding, heat and pressure are applied and the direct physical contacts between the two surfaces of integrated circuit bump and substrate bond pad can be achieved. The electrical contact resistance of a NCA/NCF joint is controlled by the pressure, roughness and NCA/NCF material properties. An accurate prediction of contact resistance can help guide experiment setup towards improving the electrical performance of NCA/NCF. In this study, a model is developed and correlated to experiments. The effects of NCA/NCF material properties on electrical contact resistance are investigated.
Holographic three-dimensional polymeric photonic crystals operating in the 1550nm window
Authors: Chen Jiaqi , Jiang Wei , Chen Xiaonan , Wang Li , Zhang Sasa , Chen Ray T.
Published: February 2007

A polygonal prism based holographic fabrication method has been demonstrated for a three-dimensional face-centered-cubic-type submicron polymer photonic crystal using both positive and negative photoresists. Special fabrication treatments have been introduced to ensure the survivability of the fabricated large area (∼1cm2) nanostructures. Scanning electron microscopy and diffraction results proved the good uniformity of the fabricated structures. With the proper design of the refraction prism the authors have achieved the required band gap for S+C bands (1460–1565nm) in the [111] direction. The transmission and reflection spectra obtained by Fourier transform infrared spectroscopy are in good agreement with simulated band structure.
Conformal mapping of ultrasonic crystals: Confining ultrasound and cochlearlike waveguiding
Authors: Bazán A. , Torres M. , Montero de Espinosa F. R. , Quintero-Torres R. , Aragón J. L.
Published: February 2007

Conformal mapping of a slab of a two-dimensional ultrasonic crystal generates a closed geometrical arrangement of ultrasonic scatterers with appealing acoustic properties. This acoustic shell is able to confine ultrasonic modes. Some of these internal resonances can be induced from an external wave source. The mapping of a linear defect produces a waveguide that exhibits a spatial-frequency selection analogous to that characteristic of a synthetic “cochlea.” Both experimental and theoretical results are reported here.
The transfer of Dryandra R.Br. to Banksia L.f. (Proteaceae)
Authors: Mast Austin R. , Thiele Kevin
Published: February 2007

Phylogenies inferred from both chloroplast and nuclear DNA regions have placed the south-west Australian genus Dryandra R. Br. (93 spp.) among the descendents of the most recent common ancestor of the more widespread Australian genus Banksia L.f. (80 spp.). Here we consider the alternative solutions to maintaining monophyly at the generic rank and choose to make new combinations and replacement names for Dryandra in Banksia. We make the new combination Banksia ser. Dryandra in Banksia subgen. Banksia for 108 of the 109 new combinations at the ranks of species, subspecies, and variety and all 18 of the replacement names. We treat Banksia subgen. Banksia as the most inclusive clade that includes the type of Banksia (B. serrata) but not B. integrifolia. We erect Banksia subgen. Spathulatae to accommodate the species in the most inclusive clade that includes B. integrifolia but not B. serrata. These two subgenera of Banksia are equivalent to the clades informally called /Cryptostomata and /Phanerostomata elsewhere. We treat one of the new combinations, Banksia subulata, as incertae sedis within Banksia subgen. Banksia.
Morphological and genetic variation within the widespread species Acacia victoriae (Mimosaceae)
Authors: Ariati Siti R. , Murphy Daniel J. , Gardner Stuart , Ladiges Pauline Y.
Published: February 2007

Morphological variation in Acacia victoriae, a species widespread in arid and semi-arid regions of Australia, was analysed by phenetic methods of classification and ordination. Three morphological groups were identified on the basis of phyllode characters and are treated as subspecies. Populations with short, elliptic and tomentose phyllodes are confirmed as A. victoriae subsp. arida Pedley; this form occurs mainly in central Australia. Populations with linear to oblong, non-tomentose phyllodes are referred to subsp. victoriae; this subspecies is the most variable and widely distributed across Australia. Populations with very long, narrow phyllodes, distributed in northern Australia from the Kimberley to Queensland, are described as fasciaria subsp. nov. A small number of non-tomentose specimens with broad elliptic phyllodes from central Australia require further assessment. Thirteen accessions previously sequenced for internal spacer regions and external spacer regions of ribosomal nuclear DNA showed genetic divergence. Six accessions of subsp. fasciaria formed a clade in a parsimony analysis, confirming that the long phyllode form is genetically distinct.
An analysis of reporting of sexually transmissible infections in indigenous Australians in mainstream Australian newspapers
Authors: Thompson Sandra C. , Green Stephanie K. , Stirling E. Jessamy , James Ross
Published: February 2007

Background: To investigate the nature of, and trends in, Australian print media coverage of sexually transmissible infections (STI) in indigenous Australians. Methods: Newspaper articles from January 1986 to June 2004 were downloaded from the Factiva database. Of 164 articles examined based on our search criteria, 100 were included for analysis. An assessment of the tone and content of each article was made by two reviewers, and data were entered and analysed using EpiInfo (Centers for Disease Control and Prevention, Atlanta, GA) Results: Most articles were serious (89%), matter of fact and information dense (50%) and critical of the subject of the article (44%). Of the articles that were emotive, 78% evoked a sense of shock or frustration. The stimulus for the article was government related in 65%; a purely academic opinion was presented in 82%; and only one viewpoint was presented in 73%. The papers publishing the greatest number of articles were The Sydney Morning Herald (31%) and The Age (18%). From 1996 there was an increase in the number of articles and improvements in the voice given to indigenous informants. This may reflect initiatives in journalism education and release of a protocol on how STI in indigenous communities should be reported. Conclusion: Overall, the style of reporting was heavy, dry and critical, written in an academic style and failed to critically examine or challenge government initiatives. The potential for print media to educate the general public is poorly utilised. Further exploration of how sensitive indigenous issues can be presented to avoid stereotyping, stigma and nihilism, while initiating more effective action, is needed.
Sexual-risk behaviour, self-perceived risk and knowledge of sexually transmissible infections among young Australians attending a music festival
Authors: Lim Megan S. C. , Hellard Margaret E. , Aitken Campbell K. , Hocking Jane S.
Published: February 2007

Background: Prevalences of sexually transmissible infections (STI), unsafe sex and abortions are increasing in Australia and people aged 16 to 29 are particularly at risk. We conducted a survey of behaviour, knowledge and perceptions of STI risk among young people attending a longstanding annual music festival called the Big Day Out. Methods: A structured questionnaire was administered to a cross-sectional sample of people aged 16 to 29 years attending a music festival (Big Day Out). Results: Completed questionnaires were collected from 939 participants (507 females, 432 males) whose median age was 20 years. Of the participants, 751 (80%) had ever had vaginal or anal sex. In the previous year, 48% had multiple partners and in the past 3 months 66% had a new partner. Of these, 224 (39%; 30% of those who had ever had sex) did not use condoms all or most of the time and were classified as being at risk of STI; however, only 24% of those so classified perceived that they were at risk of an STI. In total, 43% of all sexually experienced participants had not used a condom because they reported being drunk or high at the time. STI knowledge was poor overall and male participants, those living in non-metropolitan regions, those under the age of 20 and those with less schooling scored relatively poorly. Conclusions: Our data suggest that young men and women who attend the Big Day Out are sexually active young adults with limited knowledge of STI and blood-borne viruses who regularly engage in behaviours that put them at risk of infection.
Impact of spatiotemporally correlated images on the structure of memory
Authors: Bernacchia Alberto , Amit Daniel J.
Published: February 2007

How does experience modify what we store in long-term memory? Is it an effect of unattended experience or does it require supervision? What role is played by temporal correlations in the input stream? We present a plastic recurrent network in which memory of faces is initially embedded and then, in the absence of supervision, the presentation of temporally correlated faces drastically changes long-term memory. We model and interpret the results of recent experiments and provide predictions for future testing. The stimuli are frames of a morphing film, interpolating between two memorized faces: If the temporal order of presentation of the frame stimuli is random, then the structure of memory is basically unaffected by synaptic plasticity (memory preservation). If the temporal order is sequential, then all image frames are classified as the same memory (memory collapse). The empirical findings are reproduced in the simulated dynamics of the network, in which the evolution of neural activity is conditioned by the associated synaptic plasticity (learning). The results are captured by theoretical analysis, which leads to predictions concerning the critical parameters of the stimuli; a third phase is identified in which memory is erased (forgetting).
Suppression of HIV-specific T cell activity by lymph node CD25+regulatory T cells from HIV-infected individuals
Authors: Kinter Audrey , McNally Jonathan , Riggin Lindsey , Jackson Robert , Roby Gregg , Fauci Anthony S.
Published: February 2007

CD25+CD4+FoxP3+regulatory T (Treg) cells isolated from the peripheral blood of asymptomatic HIV-infected individuals have been demonstrated to significantly suppress HIV-specific immune responsesin vitro. CD25+Treg cell suppressor activity in the peripheral blood seems to diminish with progression of HIV disease, and it has been suggested that loss of Treg cells contributes to aberrant immune activation and disease progression. However, phenotypic studies suggest that Treg cells may migrate to, and be maintained or even expanded in, tissue sites of HIV replication. Currently, it is not known whether tissue-associated Treg cells maintain suppressive activity in the context of HIV infection, particularly in individuals with advanced disease. The present study demonstrates that CD25+Treg cells isolated from lymph nodes and peripheral blood of HIV+subjects, even those with high viral loads and/or low CD4+T cell counts, maintain potent suppressive activity against HIV-specific cytolytic T cell function. This activity was better in lymph node as compared with peripheral blood, particularly in patients with high levels of plasma viremia. In addition, the expression of certain CD25+Treg-associated markers on CD4+T cells isolated from lymph nodes differed significantly from those on CD4+T cell subsets isolated from the peripheral blood. These data suggest that CD25+Treg cell-mediated suppression of HIV-specific responses continues throughout the course of HIV disease and, because of their particularly potent suppression of HIV-specific CTL activity in lymphoid tissue, may considerably impact the ability to control HIV replicationin vivo.
Serial analysis of chromatin occupancy identifies β-catenin target genes in colorectal carcinoma cells
Authors: Yochum Gregory S. , McWeeney Shannon , Rajaraman Veena , Cleland Ryan , Peters Sandra , Goodman Richard H.
Published: February 2007

Most instances of colorectal cancer are due to abnormalities in the Wnt signaling pathway, resulting in nuclear accumulation of β-catenin. β-Catenin activates transcription of target genes primarily by associating with the T cell factor/lymphoid enhancer-binding factor (TCF/Lef) family of transcription factors. In this report, we use serial analysis of chromatin occupancy (SACO) to identify 412 high-confidence β-catenin targets in HCT116 colorectal carcinoma cells. Of these targets, 84% contained a consensus TCF motif and were occupied by TCF4
in vivo
. Examination of the flanking 5-bp residues in each consensus revealed motif-specific enrichment at neighboring sites. β-Catenin binding was localized to the 5′ promoters, internal regions, and 3′ UTRs of protein-coding genes. Furthermore, 15 components of the canonical Wnt pathway were identified as β-catenin target genes, suggesting that feed-forward and feedback mechanisms exist to modulate the Wnt signal in colon cancer cells.
Identification of STAT3 as a substrate of receptor protein tyrosine phosphatase T
Authors: Zhang Xiaodong , Guo Ailan , Yu Jianshi , Possemato Anthony , Chen Yueting , Zheng Weiping , Polakiewicz Roberto D. , Kinzler Kenneth W. , Vogelstein Bert , Velculescu Victor E. , Wang Zhenghe John
Published: February 2007

Protein tyrosine phosphatase (PTP) receptor T (
PTPRT
) is the most frequently mutated PTP in human cancers. However, the cell signaling pathways regulated by PTPRT have not yet been elucidated. Here, we report identification of signal transducer and activator of transcription 3 (STAT3) as a substrate of PTPRT. Phosphorylation of a tyrosine at amino acid Y705 is essential for the function of STAT3, and PTPRT specifically dephosphorylated STAT3 at this position. Accordingly, overexpression of normal PTPRT in colorectal cancer cells reduced the expression of STAT3 target genes. These studies illuminate a mechanism regulating the STAT3 pathway and suggest that this signaling pathway plays an important role in colorectal tumorigenesis.
Microtubule binding by dynactin is required for microtubule organization but not cargo transport
Authors: Kim Hwajin , Ling Shuo-Chien , Rogers Gregory C. , Kural Comert , Selvin Paul R. , Rogers Stephen L. , Gelfand Vladimir I.
Published: February 2007

Dynactin links cytoplasmic dynein and other motors to cargo and is involved in organizing radial microtubule arrays. The largest subunit of dynactin, p150glued, binds the dynein intermediate chain and has an N-terminal microtubule-binding domain. To examine the role of microtubule binding by p150glued, we replaced the wild-type p150glued in Drosophila melanogaster S2 cells with mutant ΔN-p150 lacking residues 1–200, which is unable to bind microtubules. Cells treated with cytochalasin D were used for analysis of cargo movement along microtubules. Strikingly, although the movement of both membranous organelles and messenger ribonucleoprotein complexes by dynein and kinesin-1 requires dynactin, the substitution of full-length p150glued with ΔN-p150glued has no effect on the rate, processivity, or step size of transport. However, truncation of the microtubule-binding domain of p150glued has a dramatic effect on cell division, resulting in the generation of multipolar spindles and free microtubule-organizing centers. Thus, dynactin binding to microtubules is required for organizing spindle microtubule arrays but not cargo motility in vivo.
Acidic Amino Acids Impart Enhanced Ca2+ Permeability and Flux in Two Members of the ATP-gated P2X Receptor Family
Authors: Samways Damien S.K. , Egan Terrance M.
Published: February 2007

P2X receptors are ATP-gated cation channels expressed in nerve, muscle, bone, glands, and the immune system. The seven family members display variable Ca2+ permeabilities that are amongst the highest of all ligand-gated channels (Egan and Khakh, 2004). We previously reported that polar residues regulate the Ca2+ permeability of the P2X2 receptor (Migita et al., 2001). Here, we test the hypothesis that the formal charge of acidic amino acids underlies the higher fractional Ca2+ currents (Pf%) of the rat and human P2X1 and P2X4 subtypes. We used patch-clamp photometry to measure the Pf% of HEK-293 cells transiently expressing a range of wild-type and genetically altered receptors. Lowering the pH of the extracellular solution reduced the higher Pf% of the P2X1 receptor but had no effect on the lower Pf% of the P2X2 receptor, suggesting that ionized side chains regulate the Ca2+ flux of some family members. Removing the fixed negative charges found at the extracellular ends of the transmembrane domains also reduced the higher Pf% of P2X1 and P2X4 receptors, and introducing these charges at homologous positions increased the lower Pf% of the P2X2 receptor. Taken together, the data suggest that COO− side chains provide an electrostatic force that interacts with Ca2+ in the mouth of the pore. Surprisingly, the glutamate residue that is partly responsible for the higher Pf% of the P2X1 and P2X4 receptors is conserved in the P2X3 receptor that has the lowest Pf% of all family members. We found that neutralizing an upstream His45 increased Pf% of the P2X3 channel, suggesting that this positive charge masks the facilitation of Ca2+ flux by the neighboring Glu46. The data support the hypothesis that formal charges near the extracellular ends of transmembrane domains contribute to the high Ca2+ permeability and flux of some P2X receptors.
Quantal Release of ATP in Mouse Cortex
Authors: Pankratov Yuriy , Lalo Ulyana , Verkhratsky Alexei , North R. Alan
Published: February 2007

Transient currents occur at rest in cortical neurones that reflect the quantal release of transmitters such as glutamate and γ-aminobutyric acid (GABA). We found a bimodal amplitude distribution for spontaneously occurring inward currents recorded from mouse pyramidal neurones in situ, in acutely isolated brain slices superfused with picrotoxin. Larger events were blocked by glutamate receptor (AMPA, kainate) antagonists; smaller events were partially inhibited by P2X receptor antagonists suramin and PPADS. The decay of the larger events was selectively prolonged by cyclothiazide. Stimulation of single intracortical axons elicited quantal glutamate-mediated currents and also quantal currents with amplitudes corresponding to the smaller spontaneous inward currents. It is likely that the lower amplitude spontaneous events reflect packaged ATP release. This occurs with a lower probability than that of glutamate, and evokes unitary currents about half the amplitude of those mediated through AMPA receptors. Furthermore, the packets of ATP appear to be released from vesicle in a subset of glutamate-containing terminals.
The RBCC GeneRFP2(Leu5) Encodes a Novel Transmembrane E3 Ubiquitin Ligase Involved in ERAD
Authors: Lerner Mikael , Corcoran Martin , Cepeda Diana , Nielsen Michael L. , Zubarev Roman , Pontén Fredrik , Uhlén Mathias , Hober Sophia , Grandér Dan , Sangfelt Olle
Published: February 2007

RFP2, a gene frequently lost in various malignancies, encodes a protein with RING finger, B-box, and coiled-coil domains that belongs to the RBCC/TRIM family of proteins. Here we demonstrate that Rfp2 is an unstable protein with auto-polyubiquitination activity in vivo and in vitro, implying that Rfp2 acts as a RING E3 ubiquitin ligase. Consequently, Rfp2 ubiquitin ligase activity is dependent on an intact RING domain, as RING deficient mutants fail to drive polyubiquitination in vitro and are stabilized in vivo. Immunopurification and tandem mass spectrometry enabled the identification of several putative Rfp2 interacting proteins localized to the endoplasmic reticulum (ER), including valosin-containing protein (VCP), a protein indispensable for ER-associated degradation (ERAD). Importantly, we also show that Rfp2 regulates the degradation of the known ER proteolytic substrate CD3-δ, but not the N-end rule substrate Ub-R-YFP (yellow fluorescent protein), establishing Rfp2 as a novel E3 ligase involved in ERAD. Finally, we show that Rfp2 contains a C-terminal transmembrane domain indispensable for its localization to the ER and that Rfp2 colocalizes with several ER-resident proteins as analyzed by high-resolution immunostaining. In summary, these data are all consistent with a function for Rfp2 as an ERAD E3 ubiquitin ligase.
The Biogenesis of the Golgi Ribbon: The Roles of Membrane Input from the ER and of GM130
Authors: Marra Pierfrancesco , Salvatore Lorena , Mironov Alexander , Di Campli Antonella , Di Tullio Giuseppe , Trucco Alvar , Beznoussenko Galina , Mironov Alexander , De Matteis Maria Antonietta
Published: February 2007

The Golgi complex in mammalian cells forms a continuous ribbon of interconnected stacks of flat cisternae. We show here that this distinctive architecture reflects and requires the continuous input of membranes from the endoplasmic reticulum (ER), in the form of pleiomorphic ER-to-Golgi carriers (EGCs). An important step in the biogenesis of the Golgi ribbon is the complete incorporation of the EGCs into the stacks. This requires the Golgi-matrix protein GM130, which continuously cycles between the cis-Golgi compartments and the EGCs. On acquiring GM130, the EGCs undergo homotypic tethering and fusion, maturing into larger and more homogeneous membrane units that appear primed for incorporation into the Golgi stacks. In the absence of GM130, this process is impaired and the EGCs remain as distinct entities. This induces the accumulation of tubulovesicular membranes, the shortening of the cisternae, and the breakdown of the Golgi ribbon. Under these conditions, however, secretory cargo can still be delivered to the Golgi complex, although this occurs less efficiently, and apparently through transient and/or limited continuities between the EGCs and the Golgi cisternae.
Abnormal prion protein in the pituitary in sporadic and variant Creutzfeldt–Jakob disease
Authors: Peden Alexander H. , Ritchie Diane L. , Uddin Hafsana P. , Dean Andrew F. , Schiller Kimberley A. F. , Head Mark W. , Ironside James W.
Published: February 2007

By using high-sensitivity Western blotting and immunohistochemistry, pituitary glands from patients with sporadic and variant Creutzfeldt–Jakob disease (sCJD and vCJD, respectively) were analysed for the presence of the protease-resistant form of the prion protein (PrPres). PrPres was detected in a greater proportion of vCJD pituitaries than sCJD pituitaries and was localized predominantly in the neurohypophysis. PrPres was also detected in a recurrent pituitary adenoma from an sCJD patient. Immunohistochemical analysis showed sparse positive labelling, predominantly in folliculostellate cells, in vCJD and sCJD adenohypophyses. The PrPres glycosylation pattern in the vCJD neurohypophyses showed a predominance of the unglycosylated band, which differed markedly from patterns found in all other vCJD tissues. The presence of PrPres in the pituitary of CJD patients at autopsy suggests that human growth hormone-related iatrogenic CJD may have indeed resulted from infectivity in collected pituitaries rather than necessarily from contamination of pituitary pools by adjacent brain tissue.
Use of pentapeptide-insertion scanning mutagenesis for functional mapping of the plum pox virus helper component proteinase suppressor of gene silencing
Authors: Varrelmann Mark , Maiss Edgar , Pilot Ruth , Palkovics Laszlo
Published: February 2007

Helper component proteinase (HC-Pro) of Plum pox virus is a multifunctional potyvirus protein that has been examined intensively. In addition to its involvement in aphid transmission, genome amplification and long-distance movement, it is also one of the better-studied plant virus suppressors of RNA silencing. The first systematic analysis using pentapeptide-insertion scanning mutagenesis of the silencing suppression function of a potyvirus HC-Pro is presented here. Sixty-three in-frame insertion mutants, each containing five extra amino acids inserted randomly within the HC-Pro protein, were analysed for their ability to suppress transgene-induced RNA silencing using Agrobacterium infiltration in transgenic Nicotiana benthamiana plants expressing green fluorescent protein. A functional map was obtained, consisting of clearly defined regions with different classes of silencing-suppression activity (wild-type, restricted and disabled). This map confirmed that the N-terminal part of the protein, which is indispensable for aphid transmission, is dispensable for silencing suppression and supports the involvement of the central region in silencing suppression, in addition to its role in maintenance of genome amplification and synergism with other viruses. Moreover, evidence is provided that the C-terminal part of the protein, previously known to be necessary mainly for proteolytic activity, also participates in silencing suppression. Pentapeptide-insertion scanning mutagenesis has been shown to be a fast and powerful tool to functionally characterize plant virus proteins.
Dynamics and genetics of PrPSc placental accumulation in sheep
Authors: Lacroux C. , Corbière F. , Tabouret G. , Lugan S. , Costes P. , Mathey J. , Delmas J. M. , Weisbecker J. L. , Foucras G. , Cassard H. , Elsen J. M. , Schelcher F. , Andréoletti O.
Published: February 2007

Placentae from scrapie-affected ewes are an important source of contamination. This study confirmed that scrapie-incubating ewes bearing susceptible genotypes could produce both abnormal prion protein (PrPSc)-positive and -negative placentae, depending only on the PRP genotype of the fetus. The results also provided evidence indicating that scrapie-incubating ARR/VRQ ewes may be unable to accumulate prions in the placenta, whatever the genotype of their progeny. Multinucleated trophoblast cells appeared to play a key role in placental PrPSc accumulation. PrPSc accumulation began in syncytiotrophoblasts before disseminating to uninucleated trophoblasts. As these result from trophoblast/uterine epithelial cell fusion, syncytiotrophoblast cells expressed maternal and fetal PrPC, whilst uninucleated trophoblast cells only expressed fetal PrPC. In ARR/VRQ scrapie-infected ewes, expression of the ARR allele by syncytiotrophoblasts appeared to prevent initiation of PrPSc placental deposition. The absence of prions in affected ARR/VRQ sheep placentae reinforces strongly the interest in ARR selection for scrapie control.
Comparison of CR36, a new heparan mimetic, and pentosan polysulfate in the treatment of prion diseases
Authors: Larramendy-Gozalo Claire , Barret Agnès , Daudigeos Estelle , Mathieu Emilie , Antonangeli Lucie , Riffet Cécile , Petit Emmanuel , Papy-Garcia Dulce , Barritault Denis , Brown Paul , Deslys Jean-Philippe
Published: February 2007

Sulfated polyanions, including pentosan polysulfate (PPS) and heparan mimetics, number among the most effective drugs that have been used in experimental models of prion disease and are presumed to act in competition with endogenous heparan sulfate proteoglycans as co-receptors for prion protein (PrP) on the cell surface. PPS has been shown to prolong the survival of animals after intracerebral perfusion and is in limited use for the experimental treatment of human transmissible spongiform encephalopathies (TSEs). Here, PPS is compared with CR36, a new heparan mimetic. Ex vivo, CR36 was more efficient than PPS in reducing PrPres in scrapie-infected cell cultures and showed long-lasting activity. In vivo, CR36 showed none of the acute toxicity observed with PPS and reduced PrPres accumulation in spleens, but had only a marginal effect on the survival time of mice infected with bovine spongiform encephalopathy. In contrast, mice treated with PPS that survived the initial toxic mortality had no detectable PrPres in the spleens and lived 185 days longer than controls (+55 %). These results show, once again, that anti-TSE drugs cannot be encouraged for human therapeutic trials solely on the basis of in vitro or ex vivo observations, but must first be subjected to in vivo animal studies.
Effect of the phosphatidylinositol 3-kinase/Akt pathway on influenza A virus propagation
Authors: Shin Yeun-Kyung , Liu Qiang , Tikoo Suresh K. , Babiuk Lorne A. , Zhou Yan
Published: February 2007

The phosphatidylinositol 3-kinase (PI3K)/Akt signalling pathway has attracted much recent interest due to its central role in modulating diverse downstream signalling pathways associated with cell survival, proliferation, differentiation, morphology and apoptosis. An increasing amount of information has demonstrated that many viruses activate the PI3K/Akt pathway to augment their efficient replication. In this study, the effect of the PI3K/Akt signalling pathway on influenza virus propagation was investigated. It was found that Akt phosphorylation was elevated in the late phase of influenza A/PR/8/34 infection in human lung carcinoma cells (A549). The PI3K-specific inhibitor LY294002 could suppress Akt phosphorylation, suggesting that influenza A virus-induced Akt phosphorylation is PI3K-dependent. UV-irradiated influenza virus failed to induce Akt phosphorylation, indicating that viral attachment and entry were not sufficient to trigger PI3K/Akt pathway activation. Blockage of PI3K/Akt activation by LY294002 and overexpression of the general receptor for phosphoinositides-1 PH domain (Grp1-PH) led to a reduction in virus yield. Moreover, in the presence of LY294002, viral RNA synthesis and viral protein expression were suppressed and, possibly as a consequence of low NP and M1 protein level, viral RNP nuclear export was also suppressed. These data suggest that the PI3K/Akt signalling pathway plays a role in influenza virus propagation.
Thioaptamer decoy targeting of AP-1 proteins influences cytokine expression and the outcome of arenavirus infections
Authors: Fennewald Susan M. , Scott Erin P. , Zhang Lihong , Yang Xianbin , Aronson Judith F. , Gorenstein David G. , Luxon Bruce A. , Shope Robert E. , Beasley David W. C. , Barrett Alan D. T. , Herzog Norbert K.
Published: February 2007

Viral haemorrhagic fever (VHF) is caused by a number of viruses, including arenaviruses. The pathogenesis is believed to involve dysregulation of cytokine production. The arenavirusesLassa virusandPichinde virushave a tropism for macrophages and other reticuloendothelial cells and both appear to suppress the normal macrophage response to virus infection. A decoy thioaptamer, XBY-S2, was developed and was found to bind to AP-1 transcription factor proteins. The P388D1 macrophage-like cell line contains members of the AP-1 family which may act as negative regulators of AP-1-controlled transcription. XBY-S2 was found to bind to Fra-2 and JunB, and enhance the induction of cytokines IL-6, IL-8 and TNF-α, while reducing the binding to AP-1 promoter elements. Administration of XBY-S2 to Pichinde virus-infected guinea pigs resulted in a significant reduction in Pichinde virus-induced mortality and enhanced the expression of cytokines from primary guinea pig macrophages, which may contribute to its ability to increase survival of Pichinde virus-infected guinea pigs. These data demonstrate a proof of concept that thioaptamers can be used to modulate the outcome ofin vivoviral infections by arenaviruses by the manipulation of transcription factors involved in the regulation of the immune response.
Central domain of a potyvirus VPg is involved in the interaction with the host translation initiation factor eIF4E and the viral protein HcPro
Authors: Roudet-Tavert G. , Michon T. , Walter J. , Delaunay T. , Redondo E. , Le Gall O.
Published: February 2007

Using recombinant proteins produced in bacteria or in infected plants, interactions between the VPg and HcPro of Lettuce mosaic potyvirus (LMV) and between LMV VPg and the lettuce translation initiation factor 4E, the cap-binding protein (eIF4E), were demonstrated in vitro. Interaction with eIF4E and HcPro both involved the same VPg central domain. The structure of this domain in the VPg context was predicted to include an amphiphilic α-helix, with the amino acids related to biological functions in various potyviruses exposed at the hydrophilic side.
Protective immune responses in guinea pigs and swine induced by a suicidal DNA vaccine of the capsid gene of swine vesicular disease virus
Authors: Sun Shi-Qi , Liu Xiang-Tao , Guo Hui-Chen , Yin Shuang-Hui , Shang You-Jun , Feng Xia , Liu Zai-Xin , Xie Qing-Ge
Published: February 2007

A suicidal DNA vaccine based on a Semliki Forest virus (SFV) replicon was evaluated for the development of a vaccine against swine vesicular disease virus (SVDV). The 1BCD gene of SVDV was cloned and inserted into pSCA1, an SFV DNA-based replicon vector. The resultant plasmid, pSCA/1BCD, was transfected into BHK-21 cells and the antigenicity of the expressed protein was confirmed using an indirect immunofluorescence assay. Immunogenicity was studied in guinea pigs and swine. Animals were injected intramuscularly three times with pSCA/1BCD at regular intervals. Anti-SVDV antibodies were detected by ELISA, the lymphocyte proliferation response was tested by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide method and neutralizing antibodies were measured by microneutralization tests. The data showed that SVDV-specific antibodies, neutralizing antibodies and lymphocyte proliferation were induced in both guinea pigs and swine. Furthermore, after three successive vaccinations with pSCA/1BCD, half of the pigs were protected against challenge with SVDV. These results should encourage further work towards the development of a DNA vaccine against SVDV.
Avian polyomavirus mutants with deletions in the VP4-encoding region show deficiencies in capsid assembly and virus release, and have reduced infectivity in chicken
Authors: Johne Reimar , Paul Guntram , Enderlein Dirk , Stahl Tobias , Grund Christian , Müller Hermann
Published: February 2007

Avian polyomavirus (APV) is the causative agent of an acute fatal disease in psittacine and some non-psittacine birds. In contrast to mammalian polyomaviruses, the APV genome encodes the additional capsid protein VP4 and its variant VP4Δ, truncated by an internal deletion. Both proteins induce apoptosis. Mutation of their common initiation codon prevents virus replication. Here, the generation of replication competent deletion mutants expressing either VP4 or VP4Δ is reported. In contrast to infection with wild-type virus, chicken embryo cells showed no cytopathic changes after infection with the mutants, and induction of apoptosis as well as virus release from the infected cells were delayed. Electron microscopy revealed the presence of a high proportion of small particles and tubules in preparations of the VP4 deletion mutant, indicating a scaffolding function for VP4. Wild-type and mutant viruses elicited neutralizing antibodies against APV after intramuscular and intraperitoneal infection of chicken; however, VP4-specific antibodies were only detected after infection with wild-type virus. Using the oculonasal route of infection, seroconversion was only observed in chickens infected with the wild-type virus, indicating a strongly reduced infectivity of the mutants. Based on the biological properties of the deletion mutants, they could be considered as candidates for APV marker vaccines.
Enterovirus 94, a proposed new serotype in human enterovirus species D
Authors: Smura Teemu P. , Junttila Nina , Blomqvist Soile , Norder Helene , Kaijalainen Svetlana , Paananen Anja , Magnius Lars O. , Hovi Tapani , Roivainen Merja
Published: February 2007

The genus Enterovirus (family Picornaviridae) contains five species with strains isolated from humans: Human enterovirus A (HEV-A), HEV-B, HEV-C, HEV-D and Poliovirus. In this study, a proposed new serotype of HEV-D was characterized. Four virus strains were isolated from sewage in Egypt and one strain from acute flaccid paralysis cases in the Democratic Republic of the Congo. The complete genome of one environmental isolate, the complete coding sequence of one clinical isolate and complete VP1 regions from the other isolates were sequenced. These isolates had 66.6–69.4 % nucleotide similarity and 74.7–76.6 % amino acid sequence similarity in the VP1 region with the closest enterovirus serotype, enterovirus 70 (EV70), suggesting that the isolates form a new enterovirus type, tentatively designated enterovirus 94 (EV94). Phylogenetic analyses including sequences of the 5′ UTR, VP1 and 3D regions demonstrated that EV94 isolates formed a monophyletic group within the species HEV-D. No evidence of recombination was found between EV94 and the other HEV-D serotypes, EV68 and EV70. Further biological characterization showed that EV94 was acid stable and had a wide cell tropism in vitro. Attempts to prevent replication with protective antibodies to known enterovirus receptors (poliovirus receptor, vitronectin α
v
β
3 receptor and decay accelerating factor) were not successful. Seroprevalence studies in the Finnish population revealed a high prevalence of this virus over the past two decades.
The UL47 gene of avian infectious laryngotracheitis virus is not essential for in vitro replication but is relevant for virulence in chickens
Authors: Helferich Dorothee , Veits Jutta , Teifke Jens P. , Mettenleiter Thomas C. , Fuchs Walter
Published: February 2007

The genome of infectious laryngotracheitis virus (ILTV) exhibits several differences from those of other avian and mammalian alphaherpesviruses. One of them is the translocation of the conserved UL47 gene from the unique long (UL) to the unique short (US) genome region, where UL47 is inserted upstream of the US4 gene homologue. As in other alphaherpesviruses, UL47 encodes a major tegument protein of ILTV particles, whereas the US4 gene product is a non-structural glycoprotein, gG, which is secreted from infected cells. For functional characterization, an ILTV recombinant was isolated in which US4 together with the 3′-terminal part of UL47 was replaced by a reporter gene cassette encoding green fluorescent protein. From this virus, UL47 and US4 single-gene deletion mutants without foreign sequences were derived and virus revertants were also generated. In vitro studies revealed that both genes were non-essential for ILTV replication in cultured cells. Whereas US4-negative ILTV exhibited no detectable growth defects, maximum virus titres of the double deletion mutant and of UL47-negative ILTV were reduced about 10-fold compared with those of wild-type virus and rescued virus. Experimental infection of chickens demonstrated that UL47-negative ILTV was significantly attenuated in vivo and was shed in reduced amounts, whereas wild-type and rescued viruses caused severe disease and high mortality rates. As all immunized animals were protected against subsequent challenge infection with virulent ILTV, the UL47 deletion mutant might be suitable as a live-virus vaccine.
Bovine papular stomatitis virus encodes a functionally distinct VEGF that binds both VEGFR-1 and VEGFR-2
Authors: Inder Marie K. , Ueda Norihito , Mercer Andrew A. , Fleming Stephen B. , Wise Lyn M.
Published: February 2007

Bovine papular stomatitis virus(BPSV), a member of the genusParapoxvirus, causes proliferative dermatitis in cattle and humans. Other species of the genus cause similar lesions, the nature of which has been attributed, at least in part, to a viral-encoded vascular endothelial growth factor (VEGF) that induces vascularization and dermal oedema through VEGF receptor-2 (VEGFR-2). The results of this study showed that BPSV strain V660 encodes a novel VEGF and that the predicted BPSV protein showed only 33–52 % amino acid identity to VEGFs encoded by the other species of the genus. BPSV VEGF showed higher identity to mammalian VEGF-A (51 %) than the other parapoxviral VEGFs (31–46 %). Assays of the purified BPSV VEGF (BPSVV660VEGF) demonstrated that it was also functionally more similar to VEGF-A, as it showed significant binding to VEGFR-1 and induced monocyte migration. Like VEGF-A and the other viral VEGFs, BPSVV660VEGF bound VEGFR-2 with high affinity. Sequence analysis and structural modelling of BPSVV660VEGF revealed specific residues, outside the known receptor-binding face, that are predicted either to influence VEGF structure or to mediate binding directly to the VEGFRs. These results indicate that BPSVV660VEGF is a biologically active member of the VEGF family and that, via its interaction with VEGFR-2, it is likely to contribute to the proliferative and highly vascularized nature of BPSV lesions. This is also the first example of a viral VEGF acting via VEGFR-1 and influencing haematopoietic cell function. These data suggest that BPSVV660VEGF is an evolutionary and functional intermediate between VEGF-A and the other parapoxviral VEGFs.
Extensive sequence variation exists among isolates of murine cytomegalovirus within members of the m02 family of genes
Authors: Corbett Alexandra J. , Forbes Catherine A. , Moro Dorian , Scalzo Anthony A.
Published: February 2007

Murine cytomegalovirus (MCMV) is a widely used model for human cytomegalovirus (HCMV) and has facilitated many important discoveries about the biology of CMVs. Most of these studies are conducted using the laboratory MCMV strains Smith and K181. However, wild-derived isolates of MCMV, like HCMV clinical isolates, exhibit genetic variation from laboratory strains, particularly at the ends of their genomes in areas containing known or putative immune-evasion and tropism genes. This study analysed the nucleotide sequence of them02–m05region, within them02gene family, of a number of laboratory and wild-derived MCMV isolates, and found a large degree of variation in both the sequence and arrangement of genes. A new open reading frame (ORF), designatedm03.5, was found to be present in a number of wild isolates of MCMV in place ofm03. Two distinct isolates, W8 and W8211, were found to possess bothm03andm03.5. Bothm03andm03.5had early transcription kinetics and the encoded proteins could be detected on the cell surface, consistent with a possible role in immune evasion through binding to host-cell proteins. These data show that gene duplication and sequence variation occur within different isolates of MCMV found in the wild. As this variation among strains may alter the function of genes, these findings should be considered when analysing gene function or host–virus interactions in laboratory models.
Phylogenetic analysis of Heliothis armigera cytoplasmic polyhedrosis virus type 14 and a series of dwarf segments found in the genome
Authors: Li Yanqiu , Zhang Jiamin , Li Yang , Tan Li , Chen Wuguo , Luo Haishan , Hu Yuanyang
Published: February 2007

Full-length nucleotide sequences for the genome segments (S1–S6) of Heliothis armigera cytoplasmic polyhedrosis virus type 14 (HaCPV-14) have been characterized. Each segment consists of a single open reading frame with conserved motifs AGAA and AGCU at the 5′ and 3′ ends, respectively. Comparison of the proteins of HaCPV-14 with those of other members of the family Reoviridae suggests that S1 encodes an RNA-dependent RNA polymerase (RdRp), whilst S2 encodes a major capsid protein of the virus. Phylogenetic analysis of RdRps from 16 viruses in the family Reoviridae reveals that the genera Cypovirus and Oryzavirus may have originated from a common insect virus ancestor. A series of viable dwarf segments originating from S5 of HaCPV-14 has been identified. Analysis of the predicted secondary structures for these dwarf segments suggests that the signals essential for replication and packaging are located within the terminal sequences of these segments.
Resolution of cervical dysplasia is associated with T-cell proliferative responses to human papillomavirus type 16 E2
Authors: Dillon Stephanie , Sasagawa Toshiyuki , Crawford Anna , Prestidge Jan , Inder Marie K. , Jerram Jim , Mercer Andrew A. , Hibma Merilyn
Published: February 2007

The ‘high-risk’ human papillomaviruses (HPVs) cause persistent infections of the anogenital region that may resolve spontaneously following activation of a protective immune response. The aim of this study was to determine whether cell-mediated immunity (CMI) to the early protein E2 was associated with disease regression and to establish whether E2 CMI and antibodies to L1 virus-like particles (VLPs) were associated markers of immunity to HPV. Lymphoproliferative responses to histidine-tagged E2 and antibody responses to VLPs were measured in patients with persistent cervical dysplasia, those whose disease had recently resolved and normal controls. Resolvers had significantly higher E2-specific lymphoproliferative responses when compared with normal controls or persisters, whereas there was no significant difference between the persisters and the normal controls. The T cells stimulated by E2 secreted high levels of gamma interferon (IFN-γ), consistent with a type 1 helper (Th1) phenotype. VLP IgG responses were associated with current or previous HPV infection, but not with disease regression or a lymphoproliferative response to E2. Major histocompatibility complex class I-restricted T cells secreted IFN-γfollowing stimulation with E1, and E2 peptides were detected more frequently in the persister group. The data showed that lymphoproliferative responses to E2 with a cytokine profile indicative of Th1 are associated with disease resolution, supporting the development of a therapeutic vaccine that activates this type of response for the treatment of individuals with pre-existing disease.
Nursing Education and Implications for Left Ventricular Assist Device Destination Therapy
Authors: Bond A. Elaine , Bolton Brandi , Nelson Karl
Published: February 2007

The HeartMate VE Left Ventricular Assist Device (vented electric abdominally positioned pulsatile blood pump; Thoratec Corp., Pleasanton, CA), approved as a permanent support, or destination therapy, by the US Food and Drug Administration in 2002 and Medicare in 2003, is now a potential therapy for numerous patients. Postimplantation nursing care is crucial to the success of left ventricular support device therapy and long‐term recipient outcome. Nurses also contribute to cost containment, making this a viable treatment for the facility and the patient. Consequently, nurses must be educated about left ventricular assist device concepts and challenges, the benefits of device placement, intensive care unit and postintensive care unit daily care requirements, and outpatient preparation. This knowledge will enable nurses to provide necessary care and to educate recipients, families, and community health care providers on how to give appropriate posthospital care.