1,720,983 research outputs found
Control of Growth and Persistence of Listeria monocytogenes and beta-Lactam-Resistant Escherichia coli by Thymol in Food Processing Settings
Get PDFThe main objective of this study was to evaluate the efficacy of thymol in controlling environmental contamination in food processing facilities. The effect of thymol was tested as an agent to prevent planktonic and bacterial biofilm growth of twenty-five Listeria monocytogenes isolates from a variety of foods and five Escherichia coli isolates from a farm. The E. coli isolates were positive for extended spectrum beta-lactamase (ESBL) genes. All isolates and reference strains were susceptible to thymol at Minimum inhibitory concentration (MIC) values ranging from 250 to 800 microg/mL. An interesting activity of interference with biofilm formation of L. monocytogenes and E. coli was found for thymol at sub-MIC concentrations of 200, 100, 75, and 50 microg/mL. Anti-biofilm activity ranging from 59.71% to 66.90% against pre-formed 24-h-old L. monocytogenes biofilms at concentrations of 500 or 800 microg/mL, corresponding to 2x MIC, was determined against free-living forms of six isolates chosen as the best or moderate biofilm producers among the tested strains. The property of thymol to attack L. monocytogenes biofilm formation was also observed at a concentration of 100 microg/mL, corresponding to 1/4 MIC, by using a stainless-steel model to simulate the surfaces in food industries. This study gives information on the use of thymol in food processing setting
Biofilm capability of staphylococcus strains isolated from food and the anti-biofilm activity of a chemically synthesized pyrrolomycin
Get PDFThis electronic document is a “live” template. The various components of your paper [title, text, tables, figures and references] are already defined on the style sheet, as illustrated by the portions given in this document
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Novel Sortase A Inhibitors to Counteract Gram-Positive Bacterial Biofilms
Get PDFSortase A (SrtA) is a membrane enzyme responsible for the covalent anchoring of surface proteins on the cell wall of Gram-positive bacteria. Nowadays it is considered an interesting target for the development of new anti-infective drugs which aim to interfere with important Gram-positive virulence mechanisms. Along the years, we studied the anti-staphylococcal and anti-biofilm activity of some natural and synthetic polyhalogenated pyrrolic compounds, called pyrrolomycins. Some of them were active on Gram-positive pathogens at a μg/mL range of concentration (1.5-0.045 μg/mL) and showed a biofilm inhibition in the range of 50-80%. [1-3] In light of these encouraging results, herein we present our efforts in the design and synthesis of novel pyrrolomycins. To dispose of sufficient amount for the in-depth in vitro investigation, we developed an efficient and easy-to-use microwave synthetic methodology. All compounds showed a good inhibitory activity toward SrtA, in accordance with the molecular modelling studies, having IC50 values ranging from 130 to 300 μM comparable to berberine hydrochloride, our reference compound. Particularly, the pentabromo-derivative exhibited the highest capability to interfere with biofilm formation of S. aureus with an IC50 of 3.4 nM. This compound was also effective in altering S. aureus murein hydrolase activity, responsible for degradation, turnover, and maturation of bacterial peptidoglycan and involved in the initial stages of S. aureus biofilm formation. [4
Composizione e attività biologica di “idrolati” di agrumi
Get PDFGli idrolati, o acque aromatiche, sono prodotti naturali ricavati dalla distillazione di piante o parti di piante fresche che conservano intatte le loro proprietà e possono essere utilizzati a diverso scopo1. Essi sono comunemente considerati un sottoprodotto degli oli essenziali, ma in realtà, data la diversa composizione e la conseguente maggiore delicatezza, hanno un loro apprezzabile utilizzo, legato comunque al mantenimento delle proprietà delle piante da cui derivano. Nell’industria agrumaria gli idrolati sono il risultato della produzione degli oli essenziali attraverso spremitura a freddo delle bucce degli agrumi e sono considerati un rifiuto da smaltire. Lo studio della composizione chimica dell’idrolato è poco noto: gli idrolati sono comunque ricchi di composti prevalentemente ossigenati che oltre a conferire un gradevole profumo, possono donargli numerose proprietà biologiche. Abbiamo quindi deciso di intraprenderne uno studio di caratterizzazione LC-MS e GC-MS sull’idrolato dell’arancia di Ribera per identificare sostanze di interesse farmaceutico, cosmetico, ecc. e di possibile attività biologica. Questo potrebbe rappresentare per l’industria agrumaria un valore aggiunto nel valorizzare un prodotto attualmente di scarto. I risultati biologici preliminari hanno indicato che l’estratto organico inibisce la crescita di forme planctoniche di S. Aureus ATCC 25923 ad una concentrazione 5 mg/mL. Sono in corso ulteriori studi per valutare l’attività contro ceppi Gram-negativi e di inibizione di biofilm di Gram-positivi e Gram-negativi. Bibliografia 1 Lante, A.; Tinello, F. Innovative Food Science and Emerging Technologies, 2015, 27, 154–15
Variations on the Author
Get PDF“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
Thiazole Analogues of the Marine Alkaloid Nortopsentin as Inhibitors of Bacterial Biofilm Formation
Get PDFAnti-virulence strategy is currently considered a promising approach to overcome the
global threat of the antibiotic resistance. Among different bacterial virulence factors, the biofilm
formation is recognized as one of the most relevant. Considering the high and growing percentage
of multi-drug resistant infections that are biofilm-mediated, new therapeutic agents capable of
counteracting the formation of biofilms are urgently required. In this scenario, a new series of
18 thiazole derivatives was efficiently synthesized and evaluated for its ability to inhibit biofilm
formation against the Gram-positive bacterial reference strains Staphylococcus aureus ATCC 25923
and S. aureus ATCC 6538 and the Gram-negative strain Pseudomonas aeruginosa ATCC 15442. Most of
the new compounds showed a marked selectivity against the Gram-positive strains. Remarkably,
five compounds exhibited BIC50 values against S. aureus ATCC 25923 ranging from 1.0 to 9.1 M.
The new compounds, affecting the biofilm formation without any interference on microbial growth,
can be considered promising lead compounds for the development of a new class of anti-virulence
agents
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
Get PDFWe 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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