1,721,019 research outputs found
Use of unsupervised and supervised artificial neural networks for the identification of lactic acid bacteria on the basis of SDS-PAGE patterns of whole cell proteins
No full textConventional multivariate statistical techniques (hierarchical cluster analysis, linear discriminant analysis) and unsupervised (Kohonen Self Organizing Map) and supervised (Bayesian network) artificial neural networks were compared for as tools for the classification and identification of 352 SDS-PAGE patterns of whole cell proteins of lactic acid bacteria belonging to 22 species of the genera Lactobacillus, Leuconostoc, Enterococcus, Lactococcus and Streptococcus including 47 reference strains.
Electrophoretic data were pre-treated using the logistic weighting function described by Piraino et al. [Piraino, P., Ricciardi, A., Lanorte, M. T., Malkhazova, I., Parente, E., 2002. A new procedure for data reduction in electrophoretic fingerprints of whole-cell proteins. Biotechnol. Lett. 24, 1477-1482]. Hierarchical cluster analysis provided a satisfactory classification of the patterns but was unable to discriminate some species (Leuconostoc, Lb. sakei/Lb. curvatus, Lb. acidophilus/Lb. helveticus, Lb. plantarum/Lb. paraplantarum, Lc. lactis/Lc. raffinolactis). A 7 × 7 Kohonen self-organizing map (KSOM), trained with the patterns of the reference strains, provided a satisfactory classification of the patterns and was able to discriminate more species than hierarchical cluster analysis. The map was used in predictive mode to identify unknown strains and provided results which in 85.5% of cases matched the classification obtained by hierarchical cluster analysis. Two supervised tools, linear discriminant analysis and a 23:5:2 Bayesian network were proven to be highly effective in the discrimination of SDS-PAGE patterns of Lc. lactis from those of other species. We conclude that data reduction by logistic weighting coupled to traditional multivariate statistical analysis or artificial neural networks provide an effective tool for the classification and identification of lactic acid bacteria on the basis of SDS-PAGE patterns of whole cell proteins
Materiali nanostrutturati e tecnologie innovative per il recupero e la conservazione dei beni architettonici: un approccio interdisciplinare
No full textSDS-PAGE patterns of whole cell proteins of Streptococcus thermophilus: impact of strain, growth phase and adaptation and relationship with stress response
No full textIn previous studies we demonstrated that a relatively large diversity of stress response patterns (acid, osmotic, oxidative, heat) exists among Streptococcus thermophilus strains. Changes in protein expression, evaluated by SDS–PAGE in 4 wild strains (CNBL7035, TH681, Y3, Sfi39) and in three Sfi39 mutants in which hrcA, ctsR and rr01 genes were inactivated showed that significant variations of proteins involved in general stress response (GSR) occur as a function of growth phase, adaptation and inactivation of stress response regulators. In this work we re-evaluate the previous results comparing two unsupervised (Hierarchical Cluster Analysis, HCA, and Principal Component Analysis, PCA) and one supervised (Partial Least Square Regression, PLSR) statistical techniques for the ability to extract information from SDS–PAGE patterns of wild type and mutant strains of S. thermophilus and to uncover relationships between protein patterns and stress tolerance. HCA and PCA are two purely descriptive techniques. The HCA showed that SDS–PAGE is an efficient tool to differentiate strains but did not shed any light on the relationships between band intensity and strain, growth phase or adaptation treatment. PCA helped to identify group of bands which covaried with the stress input factors butalso not allow to find a relationship between protein expression and stress tolerance. The PLS regression, even with the limitations due to the data set used in this study, appears as an extremely promising tools for the identification of complex relationships between design and response variables in the analysis of SDS–PAGE patterns of whole cell proteins
Effect of aeration, agitation and alginate concentration on the overall volumetric oxygen mass transfer coefficient in a bench-top stirred fermenter
No full textDiscrimination of commercial Caciocavallo cheeses on the basis of the diversity of lactic microflora and primary proteolysis
No full textPhenotypic characterization of lactic acid bacteria from sourdoughs for Altamura bread produced in Apulia (Southern Italy)
No full textIn order to study the composition of the lactic acid bacteria (LAB) community of sourdoughs used for the manufacture of
Altamura bread, a traditional durum wheat bread produced in Apulia (Southern Italy), 111 strains of LAB were isolated and
characterized. The phenotypic characterization of the isolates, carried out using a set of 29 tests, allowed the identification of
15 clusters at the 80% similarity level by hierarchical cluster analysis. Of the isolates, 88% were identified as facultatively
heterofermentative LAB (Lactobacillus plantarum, Lb. paracasei, Lb. casei) and 12% as heterofermentative LAB (Lb. brevis,
Leuconostoc mesenteroides). SDS-PAGE profiles of whole cell proteins of 68 strains confirmed the identification. Both the
diversity and structure of the lactic microflora for sourdoughs for Altamura bread varied among samples
Overall volumetric oxygen transfer coefficient in an aerated bench-top stirred fermenter in aqueous dispersions of sodium alginate
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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
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
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