1,720,977 research outputs found
Polypeptide structure of DNA polymerase I from Saccharomyces cerevisiae
No full textDNA polymerase I of the yeast Saccharomyces cerevisiae has been purified to near homogeneity. The enzyme sediments under high salt conditions as a band at 7.4 S and two polypeptides of Mr = 140,000 and 110,000 are resolved by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Both polypeptides react with rabbit anti-yeast DNA polymerase I serum and can be shown to be enzymatically active by renaturation in situ after electrophoresis on polyacrylamide gels in the presence of sodium dodecyl sulfate. This high molecular weight form of yeast DNA polymerase I is very sensitive to inhibition by aphidicolin. The biochemical properties of the enzyme and inhibitors that may aid in distinguishing yeast DNA polymerases I and II are also described
Utilizzo della metodica di ibridazione in situ e immunomarcatura con oro colloidale sul modello delle malattie emorragiche dei lagomorfi
No full textDNA synthesis catalyzed in vitro by yeast extracts using A 2 μm DNA containing plasmid as template for enzymatic DNA synthesis
No full textPartially purified cell-free extracts prepared from growing cells of the yeast Saccharomyces cerevisiae catalyze DNA synthesis directed by the chimeric plasmid BTYP-2 containing the whole 2 m DNA sequence. The biochemical properties of the reaction have been examined and inactivation studies indicate that DNA synthesis is only due to protein factors. Analysis of the products of the DNA synthesis reaction demonstrates that part of the in vitro synthesized DNA is not covalently linked to the template, thus suggesting initiation of new DNA chains. The analysis of the distribution of the labelled products at early times of reaction showed a preferential synthesis on the 2 m portion of the BTYP-2 DNA template
Utility of blotting paper for serological tests to perform monitoring programs for European Brown Hare Syndrome (EBHS)
Full text linkSince mid ‘80 the European brown hare (Lepus europeaus) populations have been
progressively declining due to several causes, including the occurrence of EBHS.
After the first outbreaks in North Italy in the ’90, the periodical EBHS cases imposed
the adoption of an articulate monitoring plan of the different hare populations,
including those from protected areas and the hunting territory. In addition to the
examination of dead animals for viral detection, such monitoring activity takes
advantage from serological survey i.e. by checking the presence of antibodies to
EBHSV. Since different types of blood sampling may be adopted according to each
situation, from 2005 to 2012, we planned to compare the serological titres obtained
by testing with cELISA: a) the “classical” serum b) samples of blood dried onto
blotting paper and c) bloody fluid from the heart cavities. The major aim was to
establish the utility of each sampling method for verifying hares’ health status and the
possibility to get data from low density areas, as hunting ones. We analysed the
following samples: a) + b = 305 animals; b) + c) = 182 animals; a) + c) = 95 animals.
Even if blotting paper and cardiac blood slightly underestimate the EBHSV antibody
titres, both these “alternative” sampling methods may be useful for field studies.
Moreover, the slightly underestimates of antibody titres do not prevent to correctly
interpret the sero-epidemiological results with regard to the understanding of
spatial/time exposure of the population to EBHS and the ability of single hares to
resist the EBHSV infection
Comparison of differential sampling methods for serological tests applied to European Brown Hare Syndrome (EBHS) monitoring programs
No full textThe European hare (Lepus europeaus) is one of the most important game animal in Europe.
Since the last twenty years the stability of European populations has been progressively declining due to several causes, among them the occurrence of European Brown Hare
Syndrome (EBHS), an highly contagious disease caused by a calicivirus, nowadays endemic in most European countries. As reported in another contribution to this conference, the first outbreaks of the disease in North Italy in the 1990s forced the adoption of serological surveillance in protected areas, in order to control the dynamics of hare populations in
relation to the spread of the virus. Thereafter the periodical reoccurrence of cases imposed the adoption of a more complete program with the aim of monitoring the whole hare population, including those dwelling in hunting territories. In fact, hunting activity may facilitate the spread of the virus and also natal dispersal rates of animals, higher in hunting areas than in non-hunting areas, may contribute to the diffusion of the disease. In addition to the examination of carcasses of dead animals for viral detection, such monitoring activity
takes advantage from serological survey i.e. by checking the presence of antibodies to EBHSV in both hares shot during hunting activity (from September to December) or those captured in restocking areas at the end of the hunting season (December-January) before
being moved and released in hunting-free areas. Since different types of blood sampling may be adopted according to each situation, we planned to compare the serological titres
obtained by testing with competitive enzyme-linked immunosorbent assay (cELISA) the “classical” serum from blood taken from ear vein with samples of blood dried onto blotting paper and also bloody samples taken directly from the heart cavities during necropsy. The
major aim was to establish the utility of each sampling method for verifying the health status of hares and particularly to check the possibility to get data from low density areas. From
2005 to 2012 we analysed the following samples: a) serum from venous blood and blotting paper of 305 animals; b) blotting paper and cardiac blood of 182 animals; c) serum from venous blood and cardiac blood of 95 animals. Two small squares of approximately 6x6 mm of side were cut from dried blotters and placed in 100 μl of phosphate-buffered saline (pH 7,4) for 1 night and then 32μl of the eluted was recovered for ELISA testing. Hearts were collected by hunters during evisceration and delivered to the laboratory, where the bloody cardiac fluid (7 μl) was obtained by pressing the heart. Even if blotting paper and cardiac blood slightly underestimate the EBHSV antibody titres, if compared to the titre of serum from venous blood, both these “alternative” sampling methods may be useful for field studies. In particular blotting paper appears easier in sampling, storing and transporting also for hunters. In addition the slightly underestimates of antibody titres do not prevent to
correctly interpret the sero-epidemiological results with regard to the understanding of spatial/time exposure of the population to EBHS and the ability of single hares to resist the EBHSV infection
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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