bluuebunny/crossref_metadata_2025_split huggingface dataset:
Akt Plays a Critical Role in Replication of Nonsegmented Negative-Stranded RNA Viruses
Authors: Sun Minghao , Fuentes Sandra M. , Timani Khalid , Sun Dengyun , Murphy Chris , Lin Yuan , August Avery , Teng Michael N. , He Biao 
Published: October 2007

ABSTRACT

The order
Mononegavirales
(comprised of nonsegmented negative-stranded RNA viruses or NNSVs) contains many important pathogens. Parainfluenza virus 5 (PIV5), formerly known as simian virus 5, is a prototypical paramyxovirus and encodes a V protein, which has a cysteine-rich C terminus that is conserved among all paramyxoviruses. The V protein of PIV5, like that of many other paramyxoviruses, plays an important role in regulating viral RNA synthesis. In this work, we show that V interacts with Akt, a serine/threonine kinase, also known as protein kinase B. Both pharmacological inhibitors and small interfering RNA against Akt1 reduced PIV5 replication, indicating that Akt plays a critical role in PIV5 replication. Furthermore, treatment with Akt inhibitors also reduced the replication of several other paramyxoviruses, as well as vesicular stomatitis virus, the prototypical rhabdovirus, indicating that Akt may play a more universal role in NNSV replication. The phosphoproteins (P proteins) of NNSVs are essential cofactors for the viral RNA polymerase complex and require heavy phosphorylation for their activity. Inhibition of Akt activity reduced the level of P phosphorylation, suggesting that Akt is involved in regulating viral RNA synthesis. In addition, Akt1 phosphorylated a recombinant P protein of PIV5 purified from bacteria. The finding that Akt plays a critical role in replication of NNSV will lead to a better understanding of how these viruses replicate, as well as novel strategies to treat infectious diseases caused by NNSVs.
Mutational Analyses of Packaging Signals in Influenza Virus PA, PB1, and PB2 Genomic RNA Segments
Authors: Liang Yuhong , Huang Taoying , Ly Hinh , Parslow Tristram G. , Liang Yuying 
Published: October 2007

ABSTRACT

The influenza A virus genome consists of eight negative-sense RNA segments that must each be packaged to produce an infectious virion. We have previously mapped the minimal
cis
-acting regions necessary for efficient packaging of the PA, PB1, and PB2 segments, which encode the three protein subunits of the viral RNA polymerase. The packaging signals in each of these RNAs lie within two separate regions at the 3′ and 5′ termini, each encompassing the untranslated region and extending up to 80 bases into the adjacent coding sequence. In this study, we introduced scanning mutations across the coding regions in each of these RNA segments in order to finely define the packaging signals. We found that mutations producing the most severe defects were confined to a few discrete 5′ sites in the PA or PB1 coding regions but extended across the entire (80-base) 5′ coding region of PB2. In sequence comparisons among more than 580 influenza A strains from diverse hosts, these highly deleterious mutations were each found to affect one or more conserved bases, though they did not all lie within the most broadly conserved portions of the regions that we interrogated. We have introduced silent and conserved mutations to the critical packaging sites, which did not affect protein function but impaired viral replication at levels roughly similar to those of their defects in RNA packaging. Interestingly, certain mutations showed strong tendencies to revert to wild-type sequences, which implies that these putative packaging signals are critical for the influenza life cycle.
Coupling Genetics and Proteomics To Identify Aphid Proteins Associated with Vector-Specific Transmission of Polerovirus (
Luteoviridae
)
Authors: Yang Xiaolong , Thannhauser T. W. , Burrows Mary , Cox-Foster Diana , Gildow Fred E. , Gray Stewart M. 
Published: October 2007

ABSTRACT

Cereal yellow dwarf virus
-RPV (CYDV-RPV) is transmitted specifically by the aphids
Rhopalosiphum padi
and
Schizaphis graminum
in a circulative nonpropagative manner. The high level of vector specificity results from the vector aphids having the functional components of the receptor-mediated endocytotic pathways to allow virus to transverse the gut and salivary tissues. Studies of F
2
progeny from crosses of vector and nonvector genotypes of
S
.
graminum
showed that virus transmission efficiency is a heritable trait regulated by multiple genes acting in an additive fashion and that gut- and salivary gland-associated factors are not genetically linked. Utilizing two-dimensional difference gel electrophoresis to compare the proteomes of vector and nonvector parental and F
2
genotypes, four aphid proteins (S4, S8, S29, and S405) were specifically associated with the ability of
S
.
graminum
to transmit CYDV-RPV. The four proteins were coimmunoprecipitated with purified RPV, indicating that the aphid proteins are capable of binding to virus. Analysis by mass spectrometry identified S4 as a luciferase and S29 as a cyclophilin, both of which have been implicated in macromolecular transport. Proteins S8 and S405 were not identified from available databases. Study of this unique genetic system coupled with proteomic analysis indicated that these four virus-binding aphid proteins were specifically inherited and conserved in different generations of vector genotypes and suggests that they play a major role in regulating polerovirus transmission.
Human Astrovirus Coat Protein Inhibits Serum Complement Activation via C1, the First Component of the Classical Pathway
Authors: Bonaparte Rheba S. , Hair Pamela S. , Banthia Deepa , Marshall Dawn M. , Cunnion Kenji M. , Krishna Neel K. 
Published: October 2007

ABSTRACTHuman astroviruses (HAstVs) belong to a family of nonenveloped, icosahedral RNA viruses that cause noninflammatory gastroenteritis, predominantly in infants. Eight HAstV serotypes have been identified, with a worldwide distribution. While the HAstVs represent a significant public health concern, very little is known about the pathogenesis of and host immune response to these viruses. Here we demonstrate that HAstV type 1 (HAstV-1) virions, specifically the viral coat protein (CP), suppress the complement system, a fundamental component of the innate immune response in vertebrates. HAstV-1 virions and purified CP both suppress hemolytic complement activity. Hemolytic assays utilizing sera depleted of individual complement factors as well as adding back purified factors demonstrated that HAstV CP suppresses classical pathway activation at the first component, C1. HAstV-1 CP bound the A chain of C1q and inhibited serum complement activation, resulting in decreased C4b, iC3b, and terminal C5b-9 formation. Inhibition of complement activation was also demonstrated for HAstV serotypes 2 to 4, suggesting that this phenomenon is a general feature of these human pathogens. Since complement is a major contributor to the initiation and amplification of inflammation, the observed CP-mediated inhibition of complement activity may contribute to the lack of inflammation associated with astrovirus-induced gastroenteritis. Although diverse mechanisms of inhibition of complement activation have been described for many enveloped animal viruses, this is the first report of a nonenveloped icosahedral virus CP inhibiting classical pathway activation at C1.
Loss of Protein Kinase PKR Expression in Human HeLa Cells Complements the Vaccinia Virus E3L Deletion Mutant Phenotype by Restoration of Viral Protein Synthesis
Authors: Zhang Ping , Jacobs Bertram L. , Samuel Charles E. 
Published: October 2007

ABSTRACT

The E3L proteins encoded by vaccinia virus bind double-stranded RNA and mediate interferon resistance, promote virus growth, and impair virus-mediated apoptosis. Among the cellular proteins implicated as targets of E3L is the protein kinase regulated by RNA (PKR). To test in human cells the role of PKR in conferring the E3L mutant phenotype, HeLa cells stably deficient in PKR generated by an RNA interference-silencing strategy were compared to parental and control knockdown cells following infection with either an E3L deletion mutant (ΔE3L) or wild-type (WT) virus. The growth yields of WT virus were comparable in PKR-sufficient and -deficient cells. By contrast, the single-cycle yield of ΔE3L virus was increased by nearly 2 log
10
in PKR-deficient cells over the impaired growth in PKR-sufficient cells. Furthermore, virus-induced apoptosis characteristic of the ΔE3L mutant in PKR-sufficient cells was effectively abolished in PKR-deficient HeLa cells. The viral protein synthesis pattern was altered in ΔE3L-infected PKR-sufficient cells, characterized by an inhibition of late viral protein expression, whereas in PKR-deficient cells, late protein accumulation was restored. Phosphorylation of both PKR and the α subunit of protein synthesis initiation factor 2 (eIF-2α) was elevated severalfold in ΔE3L-infected PKR-sufficient, but not PKR-deficient, cells. WT virus did not significantly increase PKR or eIF-2α phosphorylation in either PKR-sufficient or -deficient cells, both of which supported efficient WT viral protein production. Finally, apoptosis induced by infection of PKR-sufficient HeLa cells with ΔE3L virus was blocked by a caspase antagonist, but mutant virus growth was not rescued, suggesting that translation inhibition rather than apoptosis activation is a principal factor limiting virus growth.
Effect of Cell Polarization on Hepatitis C Virus Entry
Authors: Mee Christopher J. , Grove Joe , Harris Helen J. , Hu Ke , Balfe Peter , McKeating Jane A. 
Published: October 2007

ABSTRACT
The primary reservoir for hepatitis C virus (HCV) replication in vivo is believed to be hepatocytes within the liver. Three host cell molecules have been reported to be important entry factors for receptors for HCV: the tetraspanin CD81, scavenger receptor BI (SR-BI), and the tight-junction (TJ) protein claudin 1 (CLDN1). The recent discovery of a TJ protein as a critical coreceptor highlighted the importance of studying the effect(s) of TJ formation and cell polarization on HCV entry. The colorectal adenocarcinoma Caco-2 cell line forms polarized monolayers containing functional TJs and was found to express the CD81, SR-BI, and CLDN1 proteins. Viral receptor expression levels increased upon polarization, and CLDN1 relocalized from the apical pole of the lateral cell membrane to the lateral cell-cell junction and basolateral domains. In contrast, expression and localization of the TJ proteins ZO-1 and occludin 1 were unchanged upon polarization. HCV infected polarized and nonpolarized Caco-2 cells to comparable levels, and entry was neutralized by anti-E2 monoclonal antibodies, demonstrating glycoprotein-dependent entry. HCV pseudoparticle infection and recombinant HCV E1E2 glycoprotein interaction with polarized Caco-2 cells occurred predominantly at the apical surface. Disruption of TJs significantly increased HCV entry. These data support a model where TJs provide a physical barrier for viral access to receptors expressed on lateral and basolateral cellular domains.
ANIONIC GEMINI SURFACTANTS: SYNTHESIS AND SURFACE ACTIVE PROPERTIES
Authors: SHUKLA DIPTI , TYAGI V. K. 
Published: October 2007

New compounds bearing two phosphate groups and two long chain (dodecyl) were prepared by two-step reaction: (i) phosphorylation of dodecanol with pyrophosphoric acid, (ii) reaction of dodecyl phosphate with N ( CH 3)4 OH and 1,6-dibromo hexane. The effect of reaction variables like time and molar ratio of reactants on yield has also been reported. The 1:2:0.5 molar ratio of reactants (dodecyl phosphate, N ( CH 3)4 OH , and Br ( CH 2)6 Br , respectively) and 3 h duration resulted to give maximum yield of anionic gemini surfactants. The structure of synthesized surfactant was investigated by modern analytical techniques, viz. FT-IR, 1H NMR, 13C NMR. Amphipathic disodium phosphates were obtained by neutralization of free acids with sodium hydroxide and their surface active properties in aqueous solution were measured. These disodium phosphates possessed 77.3% anionic content and showed good water solubility. Foaming properties and wetting ability were also evaluated.
Theoretical, Statistical, and Practical Perspectives on Pattern-based Classification Approaches to the Analysis of Functional Neuroimaging Data
Authors: O'Toole Alice J. , Jiang Fang , Abdi Hervé , Pénard Nils , Dunlop Joseph P. , Parent Marc A. 
Published: October 2007

AbstractThe goal of pattern-based classification of functional neuroimaging data is to link individual brain activation patterns to the experimental conditions experienced during the scans. These “brain-reading” analyses advance functional neuroimaging on three fronts. From a technical standpoint, pattern-based classifiers overcome fatal f laws in the status quo inferential and exploratory multivariate approaches by combining pattern-based analyses with a direct link to experimental variables. In theoretical terms, the results that emerge from pattern-based classifiers can offer insight into the nature of neural representations. This shifts the emphasis in functional neuroimaging studies away from localizing brain activity toward understanding how patterns of brain activity encode information. From a practical point of view, pattern-based classifiers are already well established and understood in many areas of cognitive science. These tools are familiar to many researchers and provide a quantitatively sound and qualitatively satisfying answer to most questions addressed in functional neuroimaging studies. Here, we examine the theoretical, statistical, and practical underpinnings of pattern-based classification approaches to functional neuroimaging analyses. Pattern-based classification analyses are well positioned to become the standard approach to analyzing functional neuroimaging data.
Distinct Patterns of Neural Activity during Memory Formation of Nonwords versus Words
Authors: Otten Leun J. , Sveen Josefin , Quayle Angela H. 
Published: October 2007

Abstract
Research into the neural underpinnings of memory formation has focused on the encoding of familiar verbal information. Here, we address how the brain supports the encoding of novel information that does not have meaning. Electrical brain activity was recorded from the scalps of healthy young adults while they performed an incidental encoding task (syllable judgments) on separate series of words and “nonwords” (nonsense letter strings that are orthographically legal and pronounceable). Memory for the items was then probed with a recognition memory test. For words as well as nonwords, event-related potentials differed depending on whether an item would subsequently be remembered or forgotten. However, the polarity and timing of the effect varied across item type. For words, subsequently remembered items showed the usually observed positive-going, frontally distributed modulation from around 600 msec after word onset. For nonwords, by contrast, a negative-going, spatially widespread modulation predicted encoding success from 1000 msec onward. Nonwords also showed a modulation shortly after item onset. These findings imply that the brain supports the encoding of familiar and unfamiliar letter strings in qualitatively different ways, including the engagement of distinct neural activity at different points in time. The processing of semantic attributes plays an important role in the encoding of words and the associated positive frontal modulation.
Functional Plasticity in Ventral Temporal Cortex following Cognitive Rehabilitation of a Congenital Prosopagnosic
Authors: DeGutis Joseph M. , Bentin Shlomo , Robertson Lynn C. , D'Esposito Mark 
Published: October 2007

Abstract
We used functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) to measure neural changes associated with training configural processing in congenital prosopagnosia, a condition in which face identification abilities are not properly developed in the absence of brain injury or visual problems. We designed a task that required discriminating faces by their spatial configuration and, after extensive training, prosopagnosic MZ significantly improved at face identification. Event-related potential results revealed that although the N170 was not selective for faces before training, its selectivity after training was normal. fMRI demonstrated increased functional connectivity between ventral occipital temporal face-selective regions (right occipital face area and right fusiform face area) that accompanied improvement in face recognition. Several other regions showed fMRI activity changes with training; the majority of these regions increased connectivity with face-selective regions. Together, the neural mechanisms associated with face recognition improvements involved strengthening early face-selective mechanisms and increased coordination between face-selective and nonselective regions, particularly in the right hemisphere.
Two Takes on the Social Brain: A Comparison of Theory of Mind Tasks
Authors: Gobbini Maria Ida , Koralek Aaron C. , Bryan Ronald E. , Montgomery Kimberly J. , Haxby James V. 
Published: October 2007

Abstract
We compared two tasks that are widely used in research on mentalizing—false belief stories and animations of rigid geometric shapes that depict social interactions—to investigate whether the neural systems that mediate the representation of others' mental states are consistent across these tasks. Whereas false belief stories activated primarily the anterior paracingulate cortex (APC), the posterior cingulate cortex/precuneus (PCC/PC), and the temporo-parietal junction (TPJ)—components of the distributed neural system for theory of mind (ToM)—the social animations activated an extensive region along nearly the full extent of the superior temporal sulcus, including a locus in the posterior superior temporal sulcus (pSTS), as well as the frontal operculum and inferior parietal lobule (IPL)—components of the distributed neural system for action understanding—and the fusiform gyrus. These results suggest that the representation of covert mental states that may predict behavior and the representation of intentions that are implied by perceived actions involve distinct neural systems. These results show that the TPJ and the pSTS play dissociable roles in mentalizing and are parts of different distributed neural systems. Because the social animations do not depict articulated body movements, these results also highlight that the perception of the kinematics of actions is not necessary to activate the mirror neuron system, suggesting that this system plays a general role in the representation of intentions and goals of actions. Furthermore, these results suggest that the fusiform gyrus plays a general role in the representation of visual stimuli that signify agency, independent of visual form.
Linking Visual Attention and Number Processing in the Brain: The Role of the Temporo-parietal Junction in Small and Large Symbolic and Nonsymbolic Number Comparison
Authors: Ansari Daniel , Lyons Ian M. , van Eimeren Lucia , Xu Fei 
Published: October 2007

Abstract
There exists a long-standing debate regarding whether small and large numerosities engage different networks of processing. The ability to rapidly enumerate small (1–4) numerosities is referred to as “subitizing” and is thought to be qualitatively different from large numerosity processing. Functional neuro-imaging studies have attempted to dissociate neural correlates of small and large number processing by contrasting subitizing with counting of numerosities just outside the subitizing range. In the present study, we used functional magnetic resonance imaging (fMRI) to contrast the processing of numerosities in the “subitizing range” with numerosities requiring estimation. Participants compared sequentially presented slides of either dots or Arabic numerals for their relative magnitude. We show that comparison of nonsymbolic numerosities in the subitizing range led to activation of the right temporo-parietal junction, while at the same time this region was found to be suppressed during large numerosity processing. Furthermore, relative suppression of this region was strongly associated with faster response times. In previous studies, this region has been implicated in stimulus-driven attention.We therefore contend that activation of the temporo-parietal junction during small number processing and the suppression thereof during large numerosity comparisons reflects differential reliance on stimulus-driven versus goal-directed attentional networks in the brain.
An MEG Study of Silent Meaning
Authors: Pylkkänen Liina , McElree Brian 
Published: October 2007

Abstract
Although research on the neural bases of language has made significant progress on how the brain accesses the meanings of words, our understanding of sentence-level semantic composition remains limited. We studied the magnetoencephalography (MEG) responses elicited by expressions whose meanings involved an element not expressed in the syntax, which enabled us to investigate the brain correlates of semantic composition without confounds from syntactic composition. Sentences such as the author began the book, which asserts that an activity was begun although no activity is mentioned in the syntax, were contrasted with control sentences such as the author wrote the book, which involved no implicit meaning. These conditions were further compared with a semantically anomalous condition (the author disgusted the book). MEG responses to the object noun showed that silent meaning and anomaly are associated with distinct effects, silent meaning, but not anomaly, eliciting increased amplitudes in the anterior midline field (AMF) at 350–450 msec. The AMF was generated in ventromedial prefrontal areas, usually implicated for social cognition and theory of mind. Our results raise the possibility that silent meaning interpretation may share mechanisms with these neighboring domains of cognition.
Aviation Applications for Satellite-Based Observations of Cloud Properties, Convection Initiation, In-Flight Icing, Turbulence, and Volcanic Ash
Authors: Mecikalski John R. , Feltz Wayne F. , Murray John J. , Johnson David B. , Bedka Kristopher M. , Bedka Sarah T. , Wimmers Anthony J. , Pavolonis Michael , Berendes Todd A. , Haggerty Julie , Minnis Pat , Bernstein Ben , Williams Earle 
Published: October 2007

Advanced Satellite Aviation Weather Products (ASAP) was jointly initiated by the NASA Applied Sciences Program and the NASA Aviation Safety and Security Program in 2002. The initiative provides a valuable bridge for transitioning new and existing satellite information and products into Federal Aviation Administration (FAA) Aviation Weather Research Program (AWRP) efforts to increase the safety and efficiency of project addresses hazards such as convective weather, turbulence (clear air and cloud induced), icing, and volcanic ash, and is particularly applicable in extending the monitoring of weather over data-sparse areas, such as the oceans and other observationally remote locations.
ASAP research is conducted by scientists from NASA, the FAA AWRP's Product Development Teams (PDT), NOAA, and the academic research community. In this paper we provide a summary of activities since the inception of ASAP that emphasize the use of current-generation satellite technologies toward observing and mitigating specified aviation hazards. A brief overview of future ASAP goals is also provided in light of the next generation of satellite sensors (e.g., hyperspectral; high spatial resolution) to become operational in the 2007–18 time frame.