1,720,956 research outputs found
Self/non-self recognition in the ciliate Euplotes raikovi: characterization of Er-MAPK1, a downstream component of the autocrine signal transduction pathway. REPORT of the IXth scientific meeting of the Italian Association of Developmental and Comparative Immunobiology (IADCI), Varese
No full textIn the ciliate Euplotes raikovi, cell type-specific, water-borne signal proteins (pheromones) control self/non-self recognition phenomena by binding their target cell-surface receptors and activating downstream signal transduction pathways. Immunorecognition analyses of E. raikovi cell extracts revealed that at least three distinct protein kinases are activated (phosphorylated) in functional association with the autocrine pheromone-receptor loop that promotes the vegetative (mitogenic) cell growth. One of these kinases, designated as Er-MAPK1 (from Mitogen-Activated Protein Kinases), was structurally characterized by molecular cloning of the relevant gene. The Er-MAPK1 N-terminal half of 300 amino acids bears unmistakable structural homology with the “intestinal cell kinase” and the “male-germ cell associated kinase”, that are involved in the regulation of proliferation and differentiation of specialized animal cells. It contains all the basic structural features that are required for a MAPK catalytic activity, in particular the dual phosphorylation site represented by the Thr-Asp-Tyr motif in the activation loop. In contrast, the Er-MAPK1 C-terminal half of 331 amino acids appears to be structurally unique. It is particularly rich in glycine residues and potential sites of regulatory activities, and shows sequence motifs that clearly predicts a nuclear localization of Er-MAPK1
Invecchiamento cellulare, ossidazione dei feromoni e meccanismi di riparazione delle metionine ossidate in Euplotes raikovi
No full textCiliates of the Frasassi caves: a potential source of bioactive molecules for biotechnological applications
No full textStruttura e biologia dei feromoni dei ciliati
No full textLa ricerca è essenzialmente centrata sullo studio strutturale, funzionale e evolutivo di proteine-segnale cellula-specifiche, note come feromoni, prodotte da protozoi ciliati del genere Euplotes, che possono essere considerate i precursori evolutivi dei fattori di crescita e delle citochine degli organismi pluricellulari. L'obiettivo che questo studio si prefigge è articolato su cinque livelli. Il primo ed il secondo livello, di più immediata realizzazione, prevedono: determinazione delle cinetiche e affinità di legame tra feromoni e recettori, in combinazioni sia di natura autocrina che paracrina; caratterizzazione delle proteine coinvolte nei meccanismi di trasduzione attivate dalle interazioni feromone-recettore. Il terzo ed il quarto livello, di più lunga durata, prevedono: determinazione all'NMR della struttura tridimensionale del recettore dei feromoni della specie E. raikovi, ottenuto come proteina ricombinante; caratterizzazione degli enzimi riparatori dei danni ossidativi a carico dei feromoni legati all'invecchiamento cellulare. Il quinto livello prevede la determinazione del meccanismo genetico che determina la secrezione o la ritenzione in membrana dei feromoni in specie rispettivamente antiche e moderne, di Euplotes
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Full text linkWe 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
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