1,721,052 research outputs found
Monitoraggio longitudinale per il rilievo di Campylobacter termofili in allevamenti di tacchini da carne
No full textLongitudinal studies were conducted in commercial meat turkey farms in order to investigate on the occurrence of thermophilic Campylobacter species and to evaluate the trend of infection during the entire production cycle (i.e. from day-old chicks up to slaughter time). Furthermore, Campylobacter species distribution analysis and genetic characterization of isolates were carried out, and their antimicrobial susceptibility profile was determined. Three flocks belonging to three different intensive farms located in the province of Vicenza, Veneto region, were examined. Samples were regularly collected at weekly intervals up to Campylobacter colonization of the flocks, then twice a month up to time of slaughter. A conventional culture method and a multiplex end-point PCR assay were used for Campylobacter detection and identification, respectively. Selected isolates were genetically characterized by Random Amplified Polymorphic DNA (RAPD)–PCR and by flaA short variable region (SVR) DNA sequencing. Antimicrobial susceptibility testing of isolates was performed by disk diffusion method. A high occurrence of thermophilic Campylobacter infection was detected, with colonization of birds persisting throughout the whole production cycle. Both C. jejuni and C. coli were recovered and a high genetic diversity was observed among them. Moreover, antimicrobial-resistance appeared to be widely spread among turkey campylobacters
Genetic diversity of Streptococcus thermophilus strains isolated from Italian traditional cheeses
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Biodiversity and characterization of indigenous coagulase-negative staphylococci isolated from raw milk and cheese of North Italy
No full textThe aim of the current study was to detect coagulase-negative staphylococci (CNS) in raw milk and cheeses produced in North Italy, and to analyze isolates for their biodiversity, safety aspects and technological properties. Molecular identification methods revealed a high biodiversity among isolates and assigned them to 17 species. The most recovered species were Staphylococcus equorum (12%), Staphylococcus lentus (12%), Staphylococcus simulans (12%), Staphylococcus sciuri (10%), and Staphylococcus xylosus (9%). The presence of ten transferable antibiotic resistance (AR) genes was verified by PCR and 19% ofisolates were positive, with tet(K) being the most frequent gene (10%); interestingly, no strain carried multiple AR genes. Twenty-four isolates displayed hemolytic activity; tyrosine decarboxylase gene (tdcA) was found in two isolates, while histidine decarboxylase gene (hdcA) and enterotoxin genes (se) were not detected. Isolates were further characterized for the presence of some relevant technological properties; 16% of isolates displayed proteolytic activity and 39% lipolytic activity, while no one of the isolates was found to exhibit antimicrobial activity against Staphylococcus aureus. This study provided evidence ofa low occurrence of safety hazards in CNS isolated from dairy products
Randomly amplified polymorphic DNA (RAPD)PCR for the identification of yeasts isolated from dairy products
No full textIn the present work randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) with primers M13 and RF2 was applied to the identification at species level of yeast strains isolated from cheeses. RAPD-PCR analysis of the type strains of different yeast species gave distinctive band profiles that allowed a clear differentiation of all the considered species. Forty-two of the 48 dairy associated yeasts were clearly assigned to the species Saccharomyces cerevisiae, Kluyveromyces marxianus (anamorph Candida kefyr), Kluyveromyces lactis (anamorph Candida sphaerica), Debaryomyces hansenii (anamorph Candida famata), Yarrowia lipolytica and Torulaspora delbrueckii (anamorph Candida colliculosa). The method, which is rapid and easy to perform, could be a useful tool for the identification of yeasts present in dairy products
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
A longitudinal study on thermophilic Campylobacter spp. in commercial turkey flocks in Northern Italy: occurrence and genetic diversity
No full textPoultry are recognized as main reservoir of thermophilic campylobacters, but few studies have been carried out on commercial meat turkeys. This study was aimed at assessing the occurrence of thermophilic Campylobacter spp., their genetic diversity and the trend of the infection during the whole production cycle of 3 turkey flocks from different farms in Northern Italy. Flocks were monitored from the housing of day-old poults to slaughter time by collecting samples (meconium and cloacal swabs) at weekly intervals up to the recovery of Campylobacter spp., and then twice a month. A conventional culture method and a multiplex PCR assay were used for Campylobacter detection and identification. A subset of isolates was genetically characterized by RAPD-PCR and flaA-SVR sequencing. Although at different times, all flocks became colonized by C. jejuni and/or C. coli, which persisted throughout the whole production cycle. Overall, 9 RAPD types and 14 flaA-SVR types were detected, with differences in their distribution among flocks and sampling times. Moreover, changes in Campylobacter genotypes colonizing turkeys were observed over time within each flock. These findings suggest that Italian commercial turkeys might be widely colonized by different genotypes of C. jejuni and C. coli and differences in the distribution and epidemiological dynamics of these microorganisms might occur among flocks
Molecular characterization of culturable and viable populations of a whey starter culture from Grana Padano cheese manufacturing
No full textVariations 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
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