1,721,009 research outputs found
Batteri della famiglia Midichloriaceae (ordine Rickettsiales): possibili patogeni emergenti per i vertebrati?
No full textLa famiglia Midichloriaceae è una famiglia batterica il cui nome deriva da Midichloria mitochondrii, simbionte intramitocondriale presente nell’ovario della zecca Ixodes ricinus (Montagna et al., 2013). Le Midichloriaceae sono comparabili, per numero di specie e per complessità, alle altre due famiglie dell’ordine Rickettsiales (Rickettsiaceae ed Anaplasmataceae), di cui fanno parte diversi batteri intracellulari patogeni per l’uomo ed altri vertebrati. In seguito alla scoperta di M. mitochondrii in I. ricinus e di batteri a esso correlati in altre specie di zecca dura, altri batteri della famiglia Midichloriaceae sono stati osservati in organismi molto diversi tra loro, spaziando da artropodi parassiti (ad esempio, pulci e cimici dei letti) e organismi dei phyla Porifera e Cnidaria, fino ad arrivare a organismi acquatici quali protisti appartenenti a specie di ciliati e ad amebe patogene del genere Acanthamoeba (Montagna et al., 2013). L’associazione di alcune midichloriaceae con organismi parassiti fa supporre un loro possibile coinvolgimento nel ruolo patogeno svolto dall’ospite parassita. Questa ipotesi è in primo luogo supportata da dati molecolari e sierologici riguardanti M. mitochondrii in I. ricinus: è infatti noto che questo batterio, presente anche nelle ghiandole salivari e nel rostro della zecca, viene trasmesso all’ospite vertebrato durante il pasto di sangue (Mariconti et al., 2012; Bazzocchi et al., 2013), anche se il suo destino, una volta inoculato nell’ospite, è tutt’ora ignoto. Altre linee di evidenza riguardanti l’infettività di batteri ascritti alla famiglia Midichloriaceae sono riscontrabili nell’ipotesi di un loro coinvolgimento nello sviluppo di patologie quali la red mark syndrome/strawberry disease nella trota iridea (Onchorynchus mykiss) (Cafiso et al., 2015) e di un possibile ruolo come coadiuvante nello sviluppo delle cheratiti oculari da Ancanthamoeba spp. Tuttavia al momento la potenziale patogenicità di alcuni membri della famiglia Midichloriaceae per l’uomo e altri vertebrati deve ancora essere dimostrata. Ad esempio, in soggetti parassitati da zecca che mostrano aspetti clinici attribuibili a rickettsiosi o ehrlichiosi, ma che mancano di titolo anticorpale contro microrganismi trasmessi tipicamente con il morso da zecca, le infezioni dovrebbero essere re-investigate sulla base di segni derivanti da infezioni correlate a Midichloriaceae. In conclusione, quindi, diversi aspetti suggeriscono il possibile ruolo di alcuni membri appartenenti alla famiglia Midichloriaceae come agenti infettivi/patogeni per i vertebrati
Molecular and serological evidences of Midichloria mitochondrii transmission to vertebrate hosts during the tick bite
Full text linkThe tick Ixodes ricinus is vector of many pathogens important for human and animal health (Parola and Raoult, 2001; Socolovschi, 2009). Midichloria mitochondrii (order Rickettsiales; family Midichloriaceae) is an endosymbiont present in the salivary glands of 100% of Ixodes ricinus females. Two lines of evidence suggest a transmission of M. mitochondrii in mammalians during the tick bite: 1) detection of circulating DNA in blood samples of different animal species; 2) seropositivity toward a M. mitochondrii protein (FliD) in humans and dogs exposed to tick bite (Mariconti 2012; Bazzocchi 2013). Here we present serological and molecular results demonstrating the circulation of M. mitochondrii also in Capreolus capreolus (the host of choice for adult and nymph stages of I. ricinus), confirming that this host is a good subject to study the spread of tick-borne pathogens.
Based on these results, FliD protein and other M. mitochondrii markers could thus be extremely useful to determine the risk of infection by I. ricinus pathogens in given areas, and for investigating the epidemiological association of a variety of pathological alterations with this tick.
Here we show results of the screening of 218 human sera (50 from non endemic areas used as negative controls and 168 from subjects exposed to tick bite) collected in different areas of Germany. Results showed that 48 out of 168 sera were positive to M. mitochondrii.
These results have posed the basis for the development of a serological test for investigating the exposure of humans and animals to this tick species
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
Suspected Laminosioptes cysticola (fowl cyst mite) lesions in backyard chickens in southern England
No full textPostmortem examination of poultry from several backyard flocks in the south of England revealed five chickens (Gallus gallus) from one backyard flock with lesions compatible with the fowl cyst mite (Laminosioptes cysticola). All affected birds were mature hens and had subcutaneous and fascial, randomly scattered, 1–5 mm, calcareous nodules. Histological findings included a thin fibrous capsule, embedding glassy, pale basophilic acellular material that stained positive with von Kossa histochemistry
consistent with mineralization. There were also some granulomatous lesions, detected in two of five birds, that were biconvex and made of an accumulation of amorphous eosinophilic material, collagen-like fibrillary material and fibroblasts, embedding some yellow to brown, refractile flakes and fragments of foreign bodies (suspected acarid exoskeletal remnants). Fresh and formalin-fixed tissues were examined by PCR for mite DNA with no positive results. Laminosioptes mites may be present in British backyard poultry
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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