1,720,989 research outputs found
gSG6, une protéine salivaire d’Anopheles gambiae, candidate marqueur d’exposition à la piqure du vecteur du paludisme?
No full textLa morbidité/mortalité des maladies à transmission vectorielle est directement liée à l’exposition de l’homme aux piqûres des insectes hématophages. L’évaluation qualitative et quantitative de la réponse anticorps spécifique à la salive d’Anopheles gambiae est un marqueur d’exposition spécifique de la piqûre de ce vecteur. Dans le but d’identifier des protéines salivaires pouvant être des marqueurs spécifiques d’exposition, nous avons évalué l’antigénicité de 2 protéines salivaires d’An. gambiae, gSG6 et gSG7, exprimées sous forme recombinante. Contrairement à gSG7, une réponse anticorps IgG anti-gSG6 a été détectée chez des enfants vivant en zone de transmission du paludisme (Niakhar, Sénégal). Sur ces premiers résultats, nous avons sélectionné 6 peptides par bio-informatique, à partir de la séquence aminée de gSG6 et en prenant en compte leurs potentialités antigéniques et l'absence d'une cross-réaction vis à vis des protéines salivaires d'autres vecteurs majeurs (Aedes, Glossina, Culex, Lutzomyia) par comparaison avec les bases de données des génomes disponibles. Parmi les 6 peptides synthétisés, une réponse anticorps contre 3 de ces peptides a été observée chez des individus résidant en même zone d’endémie (Niakhar). En corrélant ces résultats avec les données entomologiques évaluant l’exposition au vecteur An. gambiae, 2 peptides semblent être des candidats marqueurs d’exposition spécifiques de la piqûre d’Anopheles. Un tel marqueur immunologique permettrait d’identifier les populations exposées aux risques de paludisme et pourrait être un critère d’efficacité dans l’évaluation des stratégies anti-vectorielles. The morbidity/mortality of vector-borne diseases is closely linked to the exposure of human host to haematophageous insects bites. Qualitative and quantitative evaluation of the specific antibody (Ab) response to whole saliva of Anopheles gambiae is a specific marker of exposure to Anopheles bites. To identify the specific salivary protein as potential marker, we evaluated the antigenicity of two salivary proteins of An. gambiae, gSG6 and gSG7, expressed in recombinant form. Contrary to gSG7, high IgG Ab response was detected to gSG6 in children living in malaria endemic area (Niakhar, Senegal). Then we selected six peptides from the amino acid sequence of gSG6 protein by bio-informatic, based on i) their antigenic properties and ii) the absence of a cross-reaction with salivary proteins of other major vectors by comparison with databases of available genomes (Aedes, Glossina, Culex, Lutzomyia). Among the six synthesized peptides, significant Ab response directed to three peptides was observed in individuals living in the same endemic area (Niakhar). In a preliminary analysis, our results showed that the Ab response against two peptides increased according to the level of exposure to An. gambiae which was evaluated by classical entomological data. These results suggested that these two peptides could be potential candidates as marker of exposure specific to the bite of Anopheles. The use of such immunological marker could allow identification of the populations with risks of malaria and could be a criterion of effectiveness in the evaluation of the anti-vectorial strategies
Humoral response to mosquito salivary proteins as serological indicator of exposure to disease vectors: IgG response to the Anopheles gambiae gSG6 and malaria.
No full textSaliva of hematophagous arthropods, injected into the vertebrate during blood feeding, triggers the production of anti-saliva IgG and IgE antibodies. This host immune response to vector saliva (from ticks, sand flies, triatomines, tsetse and mosquitoes) may be used as a marker of exposure to vector bites and indicator of disease risk. Indeed, the potential to estimate vector density through serological assays may represent a very valuable tool for epidemiological studies. Human humoral response to Anopheles saliva has been correlated with the exposure to anopheline vectors and with malaria transmission (Remoue F et al., 2006; Waitayakul A et al., 2006; Orlandi-Pradines E et al., 2007). However, saliva is a complex mixture and cross-reactivity with antigens from other mosquitoes and/or other blood-feeding arthropods may be misleading. Moreover, obtaining large amounts of mosquito saliva or salivary extracts is tedious and not easily reproducible. In this respect recent studies on the salivary transcriptomes of blood feeding vectors provided some interesting perspectives. In fact, comparative analysis clarified that the mosquito salivary repertoire includes both salivary proteins that are widely shared among Culicidae family members and proteins that are genus-specific, i.e. found only in Anopheles, but not in Aedes or Culex species, and viceversa. This finding implies that anopheline-specific proteins, if immunogenic, may be ideal serological indicators of exposure to Anopheles bites and, similarly, that Aedes-specific proteins could be used as markers of exposure to Aedes-mosquitoes. The An. gambiae salivary protein gSG6 is a small protein specifically expressed in adult female glands where it plays some important role in blood feeding (Lanfrancotti A et al., 2002; Lombardo F et al., 2009). So far gSG6 has been found only in species of the An. gambiae complex and in a few additional anophelines (An. stephensi, An. funestus and An. freeborni), whereas it is absent in culicine mosquitoes and in other blood feeding arthropods. Preliminary indications suggested that gSG6 is immunogenic (Poinsignon et al., 2008) encouraging a deeper evaluation of its possible use as epidemiological marker of exposure to Anopheles vectors. To test this hypothesis we measured the humoral immune response to the An. gambiae salivary protein gSG6 in human sera collected during three consecutive years in rural malaria hyperendemic areas of Burkina Faso. We confirmed that gSG6 is immunogenic and found that it elicits, in the exposed population, an IgG response that varies according to the level of malaria transmission. Interestingly, this anti-gSG6 IgG response: (a) is short-lived, since a drop in the IgG levels was observed during the dry low transmission season; (b) is significantly different in the two sympatric ethnic groups, Mossi and Fulani, previously shown to differentially respond to several P. falciparum antigens (Modiano D et al., 1996; Torcia MG et al., 2008); (c) starts very early, reaching a maximum in one-two years old children, and then decreases according to age. This is to our knowledge the first study employing a mosquito recombinant salivary protein for a large scale malaria epidemiological analysis. We believe that our study provides a solid indication that antibody response to anopheline-specific salivary antigens may be a reliable marker of exposure to malaria vectors suggesting that, similarly, culicine-specific salivary antigens may be exploited as markers of exposure to Aedes and Culex vectors. In conclusion salivary antigens from mosquito disease vectors may represent valuable complementary tools for epidemiological studies in settings where the assessment of classical entomological parameters would be difficult or impossible
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
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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