63 research outputs found

    Corticospinal excitability not affected by negative motor imagery or intention

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    Bien que l’imagerie motrice positive ait été bien étudiée et est utilisée en réhabilitation, l’effet de l’imagerie motrice négative est beaucoup moins connu. Le but de cette recherche était de définir si l’intention et/ou l’imagerie motrice négative serait en mesure de réduire l’effet d’une stimulation magnétique transcrânienne (SMT) sur le cortex moteur. Vingt participants ont reçu trente stimulations de SMT dans trois situations différentes : En restant passif, en portant une attention particulière aux sensations dans leur main ou en tentant de réduire l’effet de la SMT. La moitié des participants ont utilisé une stratégie d’imagerie motrice, l’autre moitié leur intention. Dans les deux cas, l’amplitude dans la condition de modulation n’a pas été réduite de façon significative.Although positive motor imagery has been widely studied and is used in rehabilitation, the effect of negative motor imagery on our motor system is less well understood. Our goal was to ascertain whether intention and/or negative visual imagery is effective in decreasing the twitch resulting from transcranial magnetic stimulation (TMS) over the primary motor cortex. Twenty participants received 30 TMS stimulations in three different conditions: remaining passive, paying particular attention to the sensations in their hand, and attempting to modulate the amplitude of the resulting movement. To do this, half the participants used an imagery strategy, whereas the other half used an intention strategy. In both cases, amplitude in the modulation condition was not significantly reduced

    Plant-made putative contraceptive peptides

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    Functional Neuroimaging Studies of Hypnosis and Meditation: A Comparative Perspective

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    Over the last few decades, an increasing number of functional neuroimaging studies have been performed with respect to hypnosis and meditation. The objective of this article is to review a number of these studies to compare the neural substrates related to different components of hypnosis and meditation. We examine neuroimaging studies conducted to explore the impact of hypnosis on the brain regions and systems involved in color perception, hand paralysis, pain, and the default-mode network (DMN). We also review neuroimaging investigations carried out to examine the neural correlates of various meditation techniques, as well as the effects of meditation on the brain mechanisms related to emotion, pain, and the DMN. Given the discrepancy existing between the findings from neuroimaging studies of hypnosis and meditation carried out in regard to pain and the DMN, we conclude that it is premature to claim that hypnosis and meditation are mediated by similar brain systems and neural mechanisms

    An endoplasmic reticulum (ER)-directed fusion protein comprising a bacterial subtilisin domain and the human cytokine interleukin 6 is efficiently cleaved in planta

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    A major limitation of plant bioreactors is the lack of suitable and cost-effective purification methods for the extraction of pharmaceutical-grade proteins. In contrast to that, there are numerous established purification systems for heterologous proteins, expressed in Escherichia coli, which are used for the commercial production of therapeutic proteins. Therefore, we wanted to adapt the BioRad Profinity eXact<sup>TM</sup> one-step protein purification system (originally designed for microbial expression platforms) to purify recombinant proteins in crude plant extracts. This system based on the prodomain of microbial subtilase as fusion partner and a column-bound subtilisin protease. The engineered protease captures and cleaves the fusion protein, retaining the tag and releasing the native protein into the eluate. The subtilase tag was fused to human interleukin 6 (IL6) and transiently expressed in Nicotiana benthamiana leaves using the MagnICON system. The fusion protein was expressed at lower levels than native IL6, suggesting it is expressed less efficiently and/or has a lower stability. However, free IL6 was also detected in the extract and was unaffected by the addition of protease inhibitors during extraction, suggesting that the fusion protein is cleaved in planta by endogenous proteases. Purification of the recombinant protein using the Profinity eXact<sup>TM</sup> system reduced the yield still further. The inefficient production of tagged IL6, coupled with the extensive losses during purification, indicate that the Profinity eXact<sup>TM</sup> system is not suitable for the extraction of IL6 from crude plant extracts.Keywords: Tobacco, transient expression, endoplasmic reticulum, Profinity protein purification, partial cleavageAfrican Journal of Biotechnology Vol. 12(3), pp. 311-31

    Development of a Decision Support System (DSS) for an integrated test system towards the effective and competitive risk assessment on transgenic plants

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    Transgenic plants need specific approaches to analyse their potential impact on environment and consumer. The procedures used to date are often too extensive and time-consuming and associated with high costs. The BioOK network was established to develop an effective and competitive risk assessment on transgenic plants based on interdisciplinary research. New and effective methods for the risk assessment were established which focus on transgene-specific effects measured in in vitro systems in the laboratory or greenhouse whenever possible. Nevertheless event-specific field experiments have to be carried out in addition to implement environmental effects e.g. on non-targets or the variability of transgene expression.

The novel methods are combined with traditional procedures to form a multiplicative integrated decision support system (DSS) for the analysis of transgenic plants. The DSS is supported by a computerized tool using specific algorithms following a decision dendrogram. The decision rules are based on baseline, indicator and threshold data identified for the specific plant species. The prototype of the DSS is developed using potato as a model plant and to be validated on a cereal. The final decision is made by scientific expert judgment.
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    Recombinant production of the human complement factor 5a in Escherichia coli

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    Up to now, the human complement factor 5a (C5a) has only been produced in small quantities in Escherichia coli in a soluble, bioactive conformation, which is not suitable for commercial production systems. This stems from the extremely high instability of C5a, as well as its aggregation-prone nature. Therefore, we analyzed several different methods for optimizing the solubility and biological activity of C5a produced by E. coli. The solubility of C5a was efficiently improved by expressing it as a glutathione-S-transferase (GST) fusion protein and, to a lesser extent, by lowering the cultivation temperature. Neither reducing the inductor concentration (isopropylthio-β-galactoside, IPTG) of the T7lac promotor nor the concomitant overexpression of endogenous chaperones was effective. However, the biological activity of the protein was improved by the overexpression of chaperones together with cultivation at 22°C, while fusion to GST slightly reduced its activity. Consequently, low cultivation temperature and the overexpression of chaperones seem to be the optimal strategy for expression of appropriate amounts of soluble and functional C5a. These findings should be the basis for the transfer to large-scale fermentation. Using C5a as an example, we showed that strain engineering in combination with specific cultivation conditions improve the production of difficult-to-express proteins in appropriate amounts and in a functional conformation facilitating the commercial manufacturing under good manufacturing practices (GMP) conditions.Keywords: Complement factor 5a (C5a), Origami 2, BL21, periplasm, cytoplasm, chaperones, Glutathione-S-Transferase (GST), temperatur

    Development of a Decision Support System (DSS) for an integrated test system towards the effective and competitive risk assessment on transgenic plants

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    Transgenic plants need specific approaches to analyse their potential impact on environment and consumer. The procedures used to date are often too extensive and time-consuming and associated with high costs. The BioOK network was established to develop an effective and competitive risk assessment on transgenic plants based on interdisciplinary research. New and effective methods for the risk assessment were established which focus on transgene-specific effects measured in in vitro systems in the laboratory or greenhouse whenever possible. Nevertheless event-specific field experiments have to be carried out in addition to implement environmental effects e.g. on non-targets or the variability of transgene expression.

The novel methods are combined with traditional procedures to form a multiplicative integrated decision support system (DSS) for the analysis of transgenic plants. The DSS is supported by a computerized tool using specific algorithms following a decision dendrogram. The decision rules are based on baseline, indicator and threshold data identified for the specific plant species. The prototype of the DSS is developed using potato as a model plant and to be validated on a cereal. The final decision is made by scientific expert judgment.
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    Pea-derived vaccines demonstrate high immunogenicity and protection in rabbits against rabbit haemorrhagic disease virus

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    Vaccines against rabbit haemorrhagic disease virus (RHDV) are commercially produced in experimentally infected rabbits. A genetically engineered and manufactured version of the major structural protein of RHDV (VP60) is considered to be an alternative approach for vaccine production. Plants have the potential to become an excellent recombinant production system, but the low expression level and insufficient immunogenic potency of plant-derived VP60 still hamper its practical use. In this study, we analysed the expression of a novel multimeric VP60-based antigen in four different plant species, including Nicotiana tabacum L., Solanum tuberosum L., Brassica napus L. and Pisum sativum L. Significant differences were detected in the expression patterns of the novel fusion antigen cholera toxin B subunit (CTB)::VP60 (ctbvp60(SEKDEL)) at the mRNA and protein levels. Pentameric CTB::VP60 molecules were only detected in N. tabacum and P. sativum, and displayed equal levels of CTB, at approximately 0.01% of total soluble protein (TSP), and traces of detectable VP60. However, strong enhancement of the CTB protein content via self-fertilization was only observed in P. sativum, where it reached up to 0.7% of TSP. In rabbits, a strong decrease in the protective vaccine dose required from 48-400 microg potato-derived VP60 [Castanon, S., Marin, M.S., Martin-Alonso, J.M., Boga, J.A., Casais, R., Humara, J.M., Ordas, R.J. and Parra, F. (1999) Immunization with potato plants expressing VP60 protein protects against rabbit hemorrhagic disease virus. J. Virol. 73, 4452-4455; Castanon, S., Martin-Alonso, J.M., Marin, M.S., Boga, J.A., Alonso, P., Parra, F. and Ordas, R.J. (2002) The effect of the promoter on expression of VP60 gene from rabbit hemorrhagic disease virus in potato plants. Plant Sci. 162, 87-95] to 0.56-0.28 microg antigenic VP60 (measured with VP60 enzyme-linked immunosorbent assay) of crude CTB::VP60 pea extracts was demonstrated. Rabbits immunized with pea-derived CTB::VP60 showed anti-VP60-specific antibodies, similar to RikaVacc((R))-immunized rabbits, and survived RHDV challenge

    BioOK – a Comprehensive System for Analysis and Risk Assessment of Genetically Modified Plants

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    Gentechnisch veränderte (GV) Pflanzen müssen im Rahmen des Zulassungsverfahrens in der EU auf ihre potentiellen Auswirkungen auf die Umwelt und die mensch­liche oder tierische Gesundheit analysiert werden. Der gegenwärtige Zulassungsprozess ist ein Konglo­merat verschiedenster Analysemethoden und extrem zeit- und kostenaufwendig. Das Anliegen von BioOK als ein multidisziplinäres wissenschaftliches Netzwerk ist die Entwicklung von maßgeschneiderten Ansätzen zur Risikoanalyse von GV Pflanzen auf der Grundlage von Ursache-Wirkungs­hypothesen mit dem Ziel des Aufbaus eines effektiven und qualifizierten Risikobewertungssystems. Die Forschungsaktivitäten von BioOK zielen auf einen Paradigmenwechsel im aktuellen Zulassungsprozess. Sie basieren auf einem modularen System, das alle Aspekte des Risikomanagements umfasst: molekulare Charakterisierung, Inhaltsstoffanalyse, agronomische Eigenschaften, Ziel- und Nichtzielorganismen, Boden und Mikroorganismen, Toxikologie, Allergenität und Überwachung nach Markt­einführung, wobei jeder Modul unterschiedliche Analysemethoden beinhaltet. Die durch BioOK angestrebte Reform des Risikobewertungsprozesses von GV Pflanzen umfasst zwei Phasen: zunächst die Optimierung der Analysemethoden selbst und dann die Etablierung eines Entscheidungsunterstützungssystems (Test Decision System – DSS), basierend auf biologischen Schwankungsbreiten (baselines), Zeigermerkmalen (indicators) und Grenzwerten (thresholds) für jede Analysemethode. BioOK hat in einer ersten Entwicklungsphase bereits optimierte Testmethoden entwickelt: Für die Inhaltsstoffanalyse wurde die Untersuchung auf substantielle Äquivalenz durch GC-MS, LC-MS und HPLC/RI Methoden vereinfacht. Ein neu eingeführtes Analyseschema zur Ermittlung potentieller Effekte von GV Pflanzen auf den Boden kombiniert ein in vitro System zur Beprobung von Rhizodepositaten von Pflanzen, die unter kontrollierten Umweltbedingen gewachsen sind, sowie die entsprechenden Bodentypen und deren Charakterisierung mit offenen und hochsensitiven molekular-chemischen Screening und Fingerprinting-Methoden. Ein neues in vitro System zur Simulation des Transports von Substanzen aus dem Darm ins Blut, das das Risiko der Aufnahme durch Mensch oder Tier zu einem frühen Zeitpunkt misst, wurde entwickelt. Um die Effektivität und Reproduzierbarkeit von Probenahmen an der Pflanze zu erhöhen, wird ein genau definiertes Probenahmeschema entwickelt. Schließlich, in Ergänzung der aktuellen Methodik zur Allgemeinen Überwachung (General Surveillance) von GV Pflanzen im Anbau, wurde eine Herangehensweise zur Abschätzung der Notwendigkeit für ein europaweites fallspezifisches (Case Specific) Monitoring beruhend auf Ursache-Wirkungsszenarien, erarbeitet. Die zweite Phase der BioOK F&E-Arbeiten konzentriert sich auf die Entwicklung eines Entscheidungsunterstützungssystems (Decision Support System, DSS). Dazu wird ein computergestütztes System implementiert, in dem alle standardisierten und validierten Methoden zu einem Entscheidungsbaum mit Knotenpunkten, definiert über biologische Schwankungsbreiten und potentielle Risiken definierenden Grenzwerten für Zeigermerkmale, zusammengeführt sind.    Genetically modified (GM) plants have to be analyzed for their potential impacts on the environment and on human or animal health before authorisation by the EU. The approval process currently refers to a conglomeration of diverse analytical methods and is intensive in time and costs. The intention of BioOK as a multidisciplinary scientific network is the development of tailor-made approaches for GM plants based on a cause-effect hypothesis to obtain an effective and qualified risk assessment system. The research activity of BioOK aims to renew the current approval process. It is based on a modular system covering all aspects of risk assessment: molecular characterisation, compound analysis, agronomic traits, target and non-target organisms, soil and micro organisms, toxicology, allergenicity and post-market monitoring, each module containing several test methods. The renewal of the risk assessment procedure intended by BioOK consists of two phases: first the optimization of test methods and second the establishment of a decision support system (DSS) based on baselines, indicators and thresholds developed for each of the methods. Optimized test methods have been developed mainly during the first phase: For compound analysis methods have been developed to ease the analysis of substantial equivalence of the events by GC-MS, LC-MS and HPLC/RI. A newly introduced testing scheme for the detection of potential effects of GM plants on soil combines an in-vitro system to collect rhizodeposits from plants grown under controlled environmental conditions and the correspon­ding bulk soil, and their characterisation by untargeted and highly sensitive molecular-chemical screening and fingerprinting technique. A novel in vitro system simula­ting the transport of substances from the gut into the blood that detects the risk of incorporation in human or animal at an early time point was developed. In order to increase the effectiveness and reproducibility of the sampling procedure we developed a valid defined sampling scheme. Finally, complementing the actual General Surveillance methodology, an approach for a Europe-wide case specific monitoring referring to cause-effect sce­narios was developed. The second phase concentrates on the development of a Decision Support System (DSS). A computer-based system will implement and merge all standardized methods in a decision tree system following decision rules defined by baseline and thresholds for indicators.   &nbsp
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