1,720,959 research outputs found
Isolation of a Novel Kluyveromyces marxianus Strain QKM-4 and Evidence of Its Volatilome Production and Binding Potentialities in the Biocontrol of Toxigenic Fungi and Their Mycotoxins
Full text linkTo overcome the economic losses associated with fungi and their toxic metabolites, environmentally safe and efficient approaches are needed. To this end, biological control using yeasts and safe bacterial strains and their products are being explored to replace synthetic fungicides. In the present study, the biocontrol effect of a yeast strain of Kluyveromyces marxianus, QKM-4, against the growth and mycotoxin synthesis potential of key toxigenic fungi was evaluated. In vitro assays were performed to find the application of yeast volatile organic compounds (VOCs) against fungal contamination on important agricultural commodities. The removal of ochratoxin A (OTA) and deoxynivalenol (DON) by living and heat-inactivated yeast cells was also explored. VOCs produced by strain QKM-4 were able to significantly limit the fungal growth of 17 fungal species belonging to genera Aspergillus, Penicillium, and Fusarium. Yeast VOCs were able to reduce OTA biosynthesis potential of Penicillium verrucosum and Aspergillus carbonarius by 99.6 and 98.7%, respectively. In vivo application of QKM-4 VOCs against Fusarium oxysporum and A. carbonarius infection on tomatoes and grapes, respectively, determined a complete inhibition of fungal spore germination. GC/MS-based analysis of yeast VOCs identified long-chain alkanes, including nonadecane, eicosane, docosane, heptacosane, hexatriacontane, and tetracosane. In vitro testing of the mycotoxin-binding potential of the living and heat-inactivated QKM-4 cells showed a reduction of OTA and DON up to 58 and 49%, respectively, from artificially contaminated buffers. Our findings clearly demonstrate the strong antifungal potential of K. marxianus QKM-4 and propose this strain as a strong candidate for application in agriculture to safeguard food and feed 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
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
Investigation and Biological Control of Toxigenic Fungi and Mycotoxins in Dairy Cattle Feed
Full text linkMycotoxins are secondary metabolites synthesized by mycotoxigenic fungi,
contaminating human and animal food and feed. Aflatoxin B1 (AFB1) and ochratoxins
(OTA) are frequently detected in animal feed products causing many health issues in
humans and animals.
In this M. Sc research work, we evidenced the presence of OTA and AFs below the EU
maximum permissible limits. Mycotoxigenic fungal strains have been isolated from the
animal feeds. The morphological and molecular identification of these toxigenic fungi
allowed the evidence of A. flavus, A. niger, A. carbonarius and P. verrucosum that
synthesize during their growth mycotoxins compounds (Aflatoxins & Ochratoxins) at
levels higher than the detection limits and the corresponding genes were evidenced.
In order to set up safe and efficient biological control strategy of these mycotoxigenic
fungi, we decided to use yeasts known to be very safe for such purpose. Thus, in the
second part of this Thesis, 14 yeast strains were isolated from different fermented food,
dairy and meat products. These strains showed a great antifungal and spectrum of
activities through the synthesis of Volatile Organic Compounds (VOCs). Among these
yeast strains, a particular strain of Kluyveromyces marxianus QKM-4, had the strongest
antifungal VOCs that we were able to identify. GC/MS based analysis of yeast VOCs showed long chain alkanes including nonadecane (C19), eicosane (C20), docosane
(C22), heptacosane (C27), hexatriacontane (C36) and tetracosane (C24) that can control
the mycotoxigenic fungal strains and their mycotoxins synthesis. Testing the mycotoxin
binding potential of the live and heat-inactivated QKM-4 cells, showed the reduction
of OTA and DON up to 58% and 49%. The findings of the present study clearly
demonstrate a strong antifungal potential of Kluyveromyces marxianus QKM-4 for its
possible application in the agriculture and food industry. In another applied part of the
present work, the strain QKM-4 of Kluyveromyces marxianus showed a great inhibition
potential of the mycotoxigenic fungal growth, spore’s germination and 100% protection
of tomato and grape fruits from the in vitro infection of the latter by mycotoxigenic
fungi for more than 10 days
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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