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Sequencing and expression analysis of the sakacin P bactericin produced by a Lactobacillus sakei strain isolated from naturally fermented sausages
No full textA Lactobacillus sakei strain, designated as I151 and isolated from naturally fermented sausages, was found to produce the sakacin P bacteriocin which is active against Listeria monocytogenes. In this study, we performed the sequencing of the gene cluster involved in the production of the sakacin P, and we followed the expression of the sppA gene, encoding for the bacteriocin, in vitro, using Rogosa-Sharpe medium, and in situ, inoculating the strain in fermented sausages as starter culture. The results obtained underlined the high similarity (>99%) of the entire sakacin P gene cluster from the L. sakei studied here with others present in strains of L. sakei already described. Moreover, from the expression experiments, it was shown that the gene is expressed during the exponential phase and that production procedures typical of fermented sausages are not turning off the expression of the gene encoding the bacteriocin. The capability of the strain studied to produce sakacin P during production is considered an advantage for its use as starter culture to improve the safety aspect of traditional fermented sausages produced in Italy
Technological characterization of a bacteriocin-producing Lactobacillus sakei and its use in fermented sausages production
No full textThe aim of this paper was the technological characterization of a Lactobacillus sakei strain, able to produce the bacteriocin sakacin P, that was originally isolated from naturally fermented sausages. Experiments were conducted in situ, using MRS-based medium, and in situ, when the strain was inoculated as starter culture in real sausage fermentation. The results obtained underlined that the strain was able to grow in conditions that are commonly used in the production line, and only lactose and high concentrations of NaCl (5% w/v) reduced the capability for bacteriocin production. When inoculated in sausages, the strain showed a good performance, being able to colonize rapidly the ecosystem. A high number of isolates, capable of producing sakacin P, were already isolated after the third day of fermentation, and persisted throughout the course of the fermentation. The inoculated strain also affected other microbial colonization trends; in fact the total bacterial count and fecal enterococci showed a rapid decrease at the end of the fermentation. Moreover, during sensory evaluation, the final sausage product received high scores for the parameters of tenderness and juiciness, with medium acidity and low rancidity. Lastly, the panelists preferred the sausages produced with the L. sakei characterized in this study when compared to a fermented sausage produced with a commercial starter
Multiphasic approach to study the bacterial ecology of fermented sausages inoculated with a commercial starter culture
No full textIn this paper, the ability of a commercial starter culture to perform a sausage fermentation is evaluated. Molecular analysis revealed the presence of several strains of the same species contained in the starter culture with different behavior during the fermentation, and the contribution of Lactobacillus curvatus, which was only marginally isolated during the transformation. Copyrigh
Optimization of conditions for profiling bacterial populations in food by culture-independent methods
No full textCaratterizzazione e studio della dinaminca di crescita di lieviti in salami a fermentazione naturale
No full textLactic acid bacteria ecology of three traditional fermented sausages produced in the North of Italy as determined by molecular methods
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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
Yeast biodiversity and dynamics during sweet wine production as determined molecular methods
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
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