933 resultados para Vesicle trafficking
Resumo:
Inositol 1,4,5-trisphosphate (IP3) receptors are ligand-gated channels that release intracellular Ca2+ stores in response to the second messenger, IP3. We investigated the potential role of IP3 receptors during nuclear envelope assembly in vitro, using Xenopus egg extracts. Previous work suggested that Ca2+ mobilization is required for nuclear vesicle fusion and implicated IP3 receptor activity. To test the involvement of IP3 receptors using selective reagents, we obtained three distinct polyclonal antibodies to the type 1 IP3 receptor. Pretreatment of membranes with two of the antibodies inhibited IP3-stimulated CA2+ release in vitro and also inhibited nuclear vesicle fusion. One inhibitory serum was directed against 420 residues within the "coupling" domain, which includes several potential regulatory sites. The other inhibitory serum was directed against 95 residues near the C terminus and identifies an inhibitory epitope(s) in this region. The antibodies had no effect on receptor affinity for IP3. Because nuclear vesicle fusion was inhibited by antibodies that block Ca2+ flux, but not by control and preimmune antibodies, we concluded that the activation of IP3 receptors is required for fusion. The signal that activates the channel during fusion is unknown.
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The syntaxin family of integral membrane proteins are thought to function as receptors for transport vesicles, with different isoforms of this family localized to various membranes throughout the cell. The yeast Pep12 protein is a syntaxin homologue which may function in the trafficking of vesicles from the trans-Golgi network to the vacuole. We have isolated an Arabidopsis thaliana cDNA by functional complementation of a yeast pep12 mutant. The Arabidopsis cDNA (aPEP12) potentially encodes a 31-kDa protein which is homologous to yeast Pep12 and to other members of the syntaxin family, indicating that this protein may function in the docking or fusion of transport vesicles with the vacuolar membrane in plant cells. Northern blot analysis indicates that the mRNA is expressed in all tissues examined, although at a very low level in leaves. The mRNA is found in all cell types in roots and leaves, as shown by in situ hybridization experiments. The existence of plant homologues of proteins of the syntaxin family indicates that the basic vesicle docking and fusion machinery may be conserved in plants as it is in yeast and mammals.
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Structural evidence has accumulated suggesting that fusion and/or translocation factors are involved in plastid membrane biogenesis. To test this hypothesis, we have developed an in vitro system in which the extent of fusion and/or translocation is monitored by the conversion of the xanthophyll epoxide (antheraxanthin) into the red ketocarotenoid (capsanthin). Only chromoplast membrane vesicles from red pepper fruits (Capsicum annuum) contain the required enzyme. Vesicles prepared from the mutant yellow cultivar are devoid of this enzyme and accumulate antheraxanthin. The fusion and/or translocation activity is characterized by complementation due to the synthesis of capsanthin and the parallel decrease of antheraxanthin when the two types of vesicles are incubated together in the presence of plastid stroma. We show that the extent of conversion is dependent upon an ATP-requiring protein that is sensitive to N-ethylmaleimide. Further purification and immunological analysis have revealed that the active factor, designated plastid fusion and/or translocation factor (Pftf), resides in a protein of 72 kDa. cDNA cloning revealed that mature Pftf has significant homology to yeast and animal (NSF) or bacterial (Ftsh) proteins involved in vesicle fusion or membrane protein translocation.
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La presente tesi analizza il reato di traffico di esseri umani in Europa, con particolare attenzione al fenomeno dello sfruttamento sessuale. La ricerca è stata condotta in parte nell’ambito del progetto “FIDUCIA. New European crimes and trust-based policy” (www.fiduciaproject.eu). La tesi è composta da 5 capitoli. Il primo capitolo introduce il reato di tratta di esseri umani, a livello globale e, successivamente, nello specifico, in Europa. Vengono presentati i fattori determinanti e le origini del fenomeno. Inoltre, ne vengono fornite le definizioni e le principali caratteristiche, in linea con i più importanti documenti internazionali sul tema. Il capitolo si chiude con una panoramica statistica, che affronta anche le criticità della raccolta di dati relativi ai reati. Il secondo capitolo analizza l’approccio correntemente adottato a livello domestico ed europeo contro la tratta. Le misure vengono presentate prima dal punto di vista teorico; successivamente ne vengono forniti esempi concreti, ad esempio convenzioni internazionali, direttive, ma anche progetti di ricerca, collaborazioni internazionali tra autorità ed ONG. Il terzo capitolo si concentra sulla tratta a fini di sfruttamento sessuale. Vengono analizzati il potenziale legame con la prostituzione, e l’approccio europeo. Segue un approfondimento dei modelli legali implementati a livello europeo ed uno studio comparato di cinque paesi membri, rappresentativi dei vari modelli di regolamentazione della prostituzione (Italia, Belgio, Polonia, Germania e Svezia). Il quarto capitolo raccoglie le interviste condotte con diversi esperti che si occupano di contrasto alla tratta: ONG italiane e straniere, referenti nazionali anti-tratta di Italia, Belgio e Germania, FRONTEX, membri del Parlamento Europeo. Nelle conclusioni, vengono proposte prima una valutazione complessiva del quadro attuale, e poi alcune raccomandazioni ai governi nazionali e agli organismi sopranazionali. In particolare, visto l’obiettivo di un contrasto omogeneo e coordinato della tratta (per sfruttamento sessuale specificamente) a livello europeo, si ritiene che un modello regolamentare uniforme della prostituzione negli stati membri possa contribuire a migliorare uniformità ad efficacia dell’approccio europeo alla tratta.
Resumo:
Toxins have been thoroughly studied for their use as therapeutic agents in search of an improvement in toxic efficiency together with a minimization of their undesired side effects. Different studies have shown how toxins can follow different intracellular pathways which are connected with their cytotoxic action inside the cells. The work herein presented describes the different pathways followed by the ribotoxin a-sarcin and the fungal RNase T1,as toxic domains of immunoconjugates with identical binding domain, the single chain variable fragment of a monoclonal antibody raised against the glycoprotein A33. According to the results obtained both immunoconjugates enter the cells via early endosomes and, while a-sarcin can translocate directly into the cytosol to exert its deathly action, RNase T1 follows a pathway that involves lysosomes and the Golgi apparatus. These facts contribute to explaining the different cytotoxicity observed against their targeted cells, and reveal how the innate properties of the toxic domain, apart from its catalytic features, can be a key factor to be considered for immunotoxin optimization.
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Women and children become victims of human trafficking and exploitation as a result of economic globalization, national history, social structures, and geographical positioning. Human trafficking has increasingly become a global crisis of human rights violations, threatening the lives of women and children in developing countries, like the Philippines. The Philippines can evolve into a model for ending the exploitation of human trafficking if the government commits to implementing internationally recognized strategies, such as strengthening the prosecution of traffickers, providing efficient support for victims, and partnering with international organizations and local non-governmental organizations to further prevent human trafficking from occurring. The results will be felt locally, nationally, and internationally, helping the global community meet the challenges of the Millennium Development Goals.
Resumo:
The expert contributors to this edited volume, representing a multidisciplinary selection of academics, examine the treatment of irregular migration, human trafficking and smuggling in EU law and policy. The various chapters explore the policy dilemmas encountered in efforts to criminalise irregular migration and humanitarian assistance to irregular immigrants. The book aims to provide academic input to informed policy-making in the next phase of the European Agenda on Migration. In his Foreword, Matthias Ruete, Director General of DG Home Affairs of the European Commission, writes: “This initiative aims to stimulate evidence-based policy-making and to bring fresh thinking to develop more effective policies. The European Commission welcomes the valuable contribution of this initiative to help close the wide gap in our knowledge about the smuggling of migrants, and especially the functioning of smuggling networks.”
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"August 3, 1989."
Organized crime and heroin trafficking : record of hearing V, February 20-21, 1985, Miami, Florida /
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Item 851-J-3