166 research outputs found

    A Presence- and Performance-Driven Framework to Investigate Interactive Networked Music Learning Scenarios

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    Cooperative music making in networked environments has been subject of extensive research, scientific and artistic. Networked music performance (NMP) is attracting renewed interest thanks to the growing availability of effective technology and tools for computer-based communications, especially in the area of distance and blended learning applications. We propose a conceptual framework for NMP research and design in the context of classical chamber music practice and learning: presence-related constructs and objective quality metrics are used to problematize and systematize the many factors affecting the experience of studying and practicing music in a networked environment. To this end, a preliminary NMP experiment on the effect of latency on chamber music duos experience and quality of the performance is introduced. The degree of involvement, perceived coherence, and immersion of the NMP environment are here combined with measures on the networked performance, including tempo trends and misalignments from the shared score. Early results on the impact of temporal factors on NMP musical interaction are outlined, and their methodological implications for the design of pedagogical applications are discussed

    MOLECULAR CHARACTERISATION OF A NOVEL ADP-RIBOSYLATING PUTATIVE TOXIN OF NEISSERIA MENINGITIDIS

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    Molecular characterisation of a novel ADP-ribosylating putative toxin of Neisseria meningitidis VEGGIi D, *BALDUCCI E, MASIGNANI V, DI MARCELLO F, SAVINO S, ARICO’ B, COMANDUCCI M, PIZZA M, RAPPUOLI R IRIS, Chiron SpA, Via Fiorentina 1, 53100 Siena Italy; *Dipartimento Scienze morfologiche e Biochimiche Comparate, Università degli Studi di Camerino, Camerino, Italy Session: Surface antigens Introduction: By computer analysis on the Neisseria meningitidis (serogroup B, MC 58 strain) genome sequence, a protein with a feature similar to known bacterial ADP-ribosylating toxins (CT produced by Vibrio cholerae, LT by Escherichia coli and PT by Bordetella pertussis) has been identified. Enzymatic assay has shown that this protein (NM-ADPRT) possesses both NAD glycohydrolase and ADP-ribosyltransferase activity. In this study we describe the identification of the putative catalytic residues, their site-directed mutagenesis, and the resulting activity of the mutants. Materials and methods: The novel NM-ADPRT and the correspondent mutants, were expressed in E. coli as C-terminus His-tag protein fusions. Site-directed mutagenesis was performed using the Multi Site-Directed Mutagenesis Kit (QuikChange). Recombinant NM-ADPRT forms were purified from E. coli in their soluble form by metal chelate affinity chromatography. Both the wild-type and the mutants were assayed for their ADP-ribosylation and NAD-glycohydolase activites, using [adenine –U-14C] NAD and agmatine as ADP-ribose acceptor. Antisera against NM-ADPRT and the mutant derivatives were obtained by immunization of CD1 mice. 20μg of each recombinant protein were given i.p. together with CFA for the first dose and IFA for the second (day 21) and the third (day 35) booster doses. Blood sample were taken on days 34 and 49. Immune sera were used in western blot and tested in a bactericidal assay. Results and discussion: On the basis of sequence homology of NM-ADPRT with LT, CT and PT we have identified the putative residues involved in enzymatic activity. These residues have been changed by site-directed mutagenesis and the purified mutant toxins have been tested for both ADP-ribosylating and NAD-glycohydrolase activities. Interestingly, some of the mutants show reduced or abolished enzymatic activity indicating that the identified residues play a role in catalysis. Antisera against the wild-type and mutant toxins have bactericidal activity. The titers induced by two mutants were higher than those induced by the wild-type form. These data suggest that the mutations introduced could influence not only the enzymatic activity but also the in vivo stability of the toxin. Conclusion: A novel ADP-ribosyltransferase has been identified in meningococcus B. Catalytic residues have been predicted by sequence homology and their role in catalysis has been confirmed by site-directed mutagenesis. These molecules are also able to induce a bactericidal response

    NarE: a novel ADP-ribosyltransferase from Neisseria meningitidis.

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    Mono ADP-ribosyltransferases (ADPRTs) are a class of functionally conserved enzymes present in prokaryotic and eukaryotic organisms. In bacteria, these enzymes often act as potent toxins and play an important role in pathogenesis. Here we report a profile-based computational approach that, assisted by secondary structure predictions, has allowed the identification of a previously undiscovered ADP-ribosyltransferase in Neisseria meningitidis (NarE). NarE shows structural homologies with E. coli heat-labile enterotoxin (LT) and cholera toxin (CT) and possesses ADP-ribosylating and NAD-glycohydrolase activities. As in the case of LT and CT, NarE catalyses the transfer of the ADP-ribose moiety to arginine residues. Despite the absence of a signal peptide, the protein is efficiently exported into the periplasm of Neisseria. The narE gene is present in 25 out of 43 strains analysed, is always present in ET-5 and Lineage 3 but absent in ET-37 and Cluster A4 hypervirulent lineages. When present, the gene is 100% conserved in sequence and is inserted upstream of and co-transcribed with the lipoamide dehydrogenase E3 gene. Possible roles in the pathogenesis of N. meningitidis are discussed

    Stratification of unresponsive patients by an independently validated index of brain complexity.

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    OBJECTIVE: Validating objective, brain-based indices of consciousness in behaviorally unresponsive patients represents a challenge due to the impossibility of obtaining independent evidence through subjective reports. Here we address this problem by first validating a promising metric of consciousness-the Perturbational Complexity Index (PCI)-in a benchmark population who could confirm the presence or absence of consciousness through subjective reports, and then applying the same index to patients with disorders of consciousness (DOCs). METHODS: The benchmark population encompassed 150 healthy controls and communicative brain-injured subjects in various states of conscious wakefulness, disconnected consciousness, and unconsciousness. Receiver operating characteristic curve analysis was performed to define an optimal cutoff for discriminating between the conscious and unconscious conditions. This cutoff was then applied to a cohort of noncommunicative DOC patients (38 in a minimally conscious state [MCS] and 43 in a vegetative state [VS]). RESULTS: We found an empirical cutoff that discriminated with 100% sensitivity and specificity between the conscious and the unconscious conditions in the benchmark population. This cutoff resulted in a sensitivity of 94.7% in detecting MCS and allowed the identification of a number of unresponsive VS patients (9 of 43) with high values of PCI, overlapping with the distribution of the benchmark conscious condition. INTERPRETATION: Given its high sensitivity and specificity in the benchmark and MCS population, PCI offers a reliable, independently validated stratification of unresponsive patients that has important physiopathological and therapeutic implications. In particular, the high-PCI subgroup of VS patients may retain a capacity for consciousness that is not expressed in behavior

    The Soluble Recombinant Neisseria meningitidis Adhesin NadAΔ351–405 Stimulates Human Monocytes by Binding to Extracellular Hsp90

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    The adhesin NadA favors cell adhesion/invasion by hypervirulent Neisseria meningitidis B (MenB). Its recombinant form NadAΔ351–405, devoid of the outer membrane domain, is an immunogenic candidate for an anti-MenB vaccine able to stimulate monocytes, macrophages and dendritic cells. In this study we investigated the molecular mechanism of NadAΔ351–405 cellular effects in monocytes. We show that NadAΔ351–405 (against which we obtained polyclonal antibodies in rabbits), binds to hsp90, but not to other extracellular homologous heat shock proteins grp94 and hsp70, in vitro and on the surface of monocytes, in a temperature dependent way. Pre-incubation of monocytes with the MenB soluble adhesin interfered with the binding of anti-hsp90 and anti-hsp70 antibodies to hsp90 and hsp70 at 37°C, a condition in which specific cell-binding occurs, but not at 0°C, a condition in which specific cell-binding is very diminished. Conversely, pre-incubation of monocytes with anti-hsp90 and anti-hsp70 antibodies did not affected NadAΔ351–405 cell binding in any temperature condition, indicating that it associates to another receptor on their plasma membrane and then laterally diffuses to encounter hsp90. Consistently, polymixin B interfered with NadAΔ351–405 /hsp90 association, abrogated the decrease of anti-hsp90 antibodies binding to the cell surface due to NadAΔ351–405 and inhibited adhesin-induced cytokine/chemokine secretion without affecting monocyte-adhesin binding. Co-stimulation of monocytes with anti-hsp90 antibodies and NadAΔ351–405 determined a stronger but polymixin B insensitive cell activation. This indicated that the formation of a recombinant NadA/hsp90/hsp70 complex, although essential for full monocyte stimulation, can be replaced by anti-hsp90 antibody/hsp90 binding. Finally, the activation of monocytes by NadAΔ351–405 alone or in the presence of anti-hsp90 antibodies were both inhibited by neutralizing anti-TLR4 antibodies, but not by anti-TLR2 antibodies. We propose that hsp90-dependent recruitment into an hsp90/hsp70/TLR4 transducing signal complex is necessary for the immune-stimulating activity of NadAΔ351–405 anti-MenB vaccine candidate

    Excitability of the supplementary motor area in Parkinson's disease depends on subcortical damage

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    Background: Cortical dysfunctioning significantly contributes to the pathogenesis of motor symptoms in Parkinson's disease (PD). Objective: We aimed at testing whether an acute levodopa administration has measurable and specific cortical effects possibly related to striatal dopaminergic deficit. Methods: In thirteen PD patients, we measured the electroencephalographic responses to transcranial magnetic stimulation (TMS/EEG) of the supplementary motor area and superior parietal lobule (n = 8) before and after an acute intake of levodopa. We also performed a single-photon emission computed tomography and [123I]N-\u3c9-fluoropropyl-2\u3b2-carbomethoxy-3\u3b2-(4-iodophenyl)nortropane to identify the more affected and the less affected brain side in each patient, according to the dopaminergic innervation loss of the putamen. Cortical excitability changes before and after an acute intake of levodopa were computed and compared between the more and the less affected brain side at the single-patient as well as at the group level. Results: We found that levodopa intake induces a significant increase (P < 0.01) of cortical excitability nearby the supplementary motor area in the more affected brain side, greater (P < 0.025) than in the less affected brain side. Notably, cortical excitability changes nearby the superior parietal lobule were not statistically significant. Conclusions: These results strengthen the idea that dysfunction of specific cortico-subcortical circuits may contribute to pathophysiology of PD symptoms. Most important, they support the use of navigated TMS/EEG as a non-invasive tool to better understand the pathophysiology of PD

    Vaccination against Neisseria meningitidis Using Three Variants of the Lipoprotein GNA1870

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    Sepsis and meningitis caused by serogroup B meningococcus are devastating diseases of infants and young adults, which cannot yet be prevented by vaccination. By genome mining, we discovered GNA1870, a new surface-exposed lipoprotein of Neisseria meningitidis that induces high levels of bactericidal antibodies. The antigen is expressed by all strains of N. meningitidis tested. Sequencing of the gene in 71 strains representative of the genetic and geographic diversity of the N. meningitidis population, showed that the protein can be divided into three variants. Conservation within each variant ranges between 91.6 to 100%, while between the variants the conservation can be as low as 62.8%. The level of expression varies between strains, which can be classified as high, intermediate, and low expressors. Antibodies against a recombinant form of the protein elicit complement-mediated killing of the strains that carry the same variant and induce passive protection in the infant rat model. Bactericidal titers are highest against those strains expressing high yields of the protein; however, even the very low expressors are efficiently killed. The novel antigen is a top candidate for the development of a new vaccine against meningococcus

    Molecular Epidemiology of Neisseria meningitidis Serogroup B in Brazil

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    Background: Neisseria meningitidis serogroup B has been predominant in Brazil, but no broadly effective vaccine is available to prevent endemic meningococcal disease. To understand genetic diversity among serogroup B strains in Brazil, we selected a nationally representative sample of clinical disease isolates from 2004, and a temporally representative sample for the state of SĂŁo Paulo (1988-2006) for study (n = 372). Methods: We performed multi-locus sequence typing (MLST) and sequence analysis of five outer membrane protein (OMP) genes, including novel vaccine targets fHbp and nadA. Results: In 2004, strain B:4:P1.15,19 clonal complex ST-32/ET-5 (cc32) predominated throughout Brazil; regional variation in MLST sequence type (ST), fetA, and porB was significant but diversity was limited for nadA and fHbp. Between 1988 and 1996, the SĂŁo Paulo isolates shifted from clonal complex ST-41/44/Lineage 3 (cc41/44) to cc32. OMP variation was associated with but not predicted by cc or ST. Overall, fHbp variant 1/subfamily B was present in 80% of isolates and showed little diversity. The majority of nadA were similar to reference allele 1. Conclusions: A predominant serogroup B lineage has circulated in Brazil for over a decade with significant regional and temporal diversity in ST, fetA, and porB, but not in nadA and fHbp

    A multimodal dataset for authoring and editing multimedia content:the MAMEM project

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    We present a dataset that combines multimodal biosignals and eye tracking information gathered under a human-computer interaction framework. The dataset was developed in the vein of the MAMEM project that aims to endow people with motor disabilities with the ability to edit and author multimedia content through mental commands and gaze activity. The dataset includes EEG, eye-tracking, and physiological (GSR and Heart rate) signals collected from 34 individuals (18 able-bodied and 16 motor-impaired). Data were collected during the interaction with specifically designed interface for web browsing and multimedia content manipulation and during imaginary movement tasks. The presented dataset will contribute towards the development and evaluation of modern human-computer interaction systems that would foster the integration of people with severe motor impairments back into society.</p

    Stratification of unresponsive patients by an independently validated index of brain complexity

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    Objective: Validating objective, brain-based indices of consciousness in behaviorally unresponsive patients represents a challenge due to the impossibility of obtaining independent evidence through subjective reports. Here we address this problem by first validating a promising metric of consciousness\u2014the Perturbational Complexity Index (PCI)\u2014in a benchmark population who could confirm the presence or absence of consciousness through subjective reports, and then applying the same index to patients with disorders of consciousness (DOCs). Methods: The benchmark population encompassed 150 healthy controls and communicative brain-injured subjects in various states of conscious wakefulness, disconnected consciousness, and unconsciousness. Receiver operating characteristic curve analysis was performed to define an optimal cutoff for discriminating between the conscious and unconscious conditions. This cutoff was then applied to a cohort of noncommunicative DOC patients (38 in a minimally conscious state [MCS] and 43 in a vegetative state [VS]). Results: We found an empirical cutoff that discriminated with 100% sensitivity and specificity between the conscious and the unconscious conditions in the benchmark population. This cutoff resulted in a sensitivity of 94.7% in detecting MCS and allowed the identification of a number of unresponsive VS patients (9 of 43) with high values of PCI, overlapping with the distribution of the benchmark conscious condition. Interpretation: Given its high sensitivity and specificity in the benchmark and MCS population, PCI offers a reliable, independently validated stratification of unresponsive patients that has important physiopathological and therapeutic implications. In particular, the high-PCI subgroup of VS patients may retain a capacity for consciousness that is not expressed in behavior. Ann Neurol 2016;80:718\u2013729
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