1,720,958 research outputs found
Catena leggera della neurotossina botulinica tipo C : clonazione, espressione, purificazione e caratterizzazione strutturale
No full textRAB11, une petite GTPase des endosomes de recyclage (étude de trois de ses partenaires et de son rôle dans la mélalogénèse)
No full textRab 11 est une GTPase principalement associée au compartiment endosomal de recyclage (ERC) où elle joue un rôle d'organisateur de ces membranes. Dans les cellules Mnt1, Rab11 colocalise partiellement avec la forme immature de Pmel17, une protéine de la matrice mélanosomale. La surexpression de Rab11wt et Q70L perturbe la distribution de la forme mature de Pmel17 et induit une diminution de la mélanine intracellulaire. Nous avons démontré que Rab11 joue un rôle dans la maturation de Pmel17, puisque le mutant Q70L induit une accumulation d'une de ses formes précurseurs. De plus, Rab11 interagit avec la queue cytoplasmique de Pmel17. Trois nouveaux partenaires de Rab11 ont été étudié. Le premier correspond à la chaîne Beta3B du complexe adaptateur AP-3. Nous avons démontré que les mélanocytes Mnt1 expriment la sous-unité Beta3B et qu'elle colocalise partiellement avec Rab11. A l'aide d'un essai in vitro, nous avons démontré que Rab11 intervient dans le recrutement du complexe AP3 neuronal sur les membranes du ERC. Nos données suggèrent un rôle de Rab11 dans la maturation de Pmel17 lors de son passage par des compartiments endosomaux de recyclage vers les structures mélanosomales. Au niveau du ERC, l'interaction Rab11/AP-3BetaB pourrait intervenir dans la ségrégation de Pmel17. Le deuxième partenaire correspond à RCP, une protéine interagissant avec Rab11 et Rab4. Nos résultats démontrent que RCP est une nouvelle protéine impliquée dans le recyclage endosomal. Enfin, le dernier partenaire correspond à la protéine Rab3lP, homologue des deux GEF Sec2p et GRAB et interagissant aussi avec Rab3. In vitro, nous avons mis en évidence une activité d'échange qui est pourtant plutôt faible. Néanmoins, in vivo, par des techniques de FRAP, nous avons obtenu des résultats qui confirment une activité GEF de Rab3IP sur Rab11. La surexpression de Rab3IP induit une redistribution intracellulaire du TfR analogue à celle induite par les formes mutantes constitutivement actives de Rab11.Rab11 is a small GTPase localized on endosomal recycling compartment (ERC) membranes and implicated in membrane organization and protein recycling to plasma membrane. The molecular mechanisms of membrane traffic leading to melanosome biogenesis are poorly understood. We demonstrate here that active mutated forms of Rab11 reduce the melanin content of melanocytes, while a corresponding Rab4 mutant does not. We show that this is mainly due to the inhibition of the processing and transport of Pmel17, a protein involved in the early stages of melanosome biogenesis. We also provide evidence that Rab11 directly binds to the cytoplasmic tail of Pmel17. Moreover, we found that the neurospecific BetaB subunit of the AP-3 coat complex is associated with Rab11 positive membranes in melanocytic cells and specifically interacts with Rab11. Our results constitute the first evidence that a Rab protein, through specific interactions with tissue-specific coat complex and cargo, regulates sorting from a compartment related to the ERC toward later stages of membrane maturation. Besides these results, were identified by two hybrid screens two novel Rab11 partners. The first, called RCP (Rab coupling protein) is an endosomal membrane-associated protein Interacting both with Rab11 and Rab4. We demonstrated that RCP is implicated in endosomal recycling. The second partner corresponds to Rab3IP, the human orthologue of rat Rabin 3, a previously identified Rab3A interacting protein with sequence homology to two Rab Guanine nucleotide Exchange Factors (Sec2p and GRAB). In vitro results indicate that Rab3lP has a weak exchange activity on Rab11. Furthermore, over-expression of GFP-tagged Rab3IP in HeLa cells induces a phenotype closely related to that generated by Rab11 dominant-positive mutant. Finally, using FRAP experiments, we were able to demonstrate that the fluorescence recovery of GFP-Rab11 after photobleaching of the pericentriolar area is affected in cell co-expressing YFP-Rab3IP.ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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