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Exploring the metabolism of Streptomyces coelicolor using mass spectrometry-based metabolomics
No full textMicro-organismen spelen een belangrijke rol in onze levens: ze worden gebruikt in de industriële productie van brood, kaas, wijn, en bier, maar ook van vele waardevolle chemische stoffen zoals medicijnen en biobrandstoffen. Bovendien leven er enorme aantallen bacteriën en schimmels in het menselijke darmstelsel, waar velen van hen helpen om onze gezondheid op peil te houden. Tegelijkertijd zijn micro-organismen natuurlijk ook verantwoordelijk voor wijdverbreide infectieziekten zoals tuberculose.
In haar proefschrift beschrijft Elena Merlo een verkenning van het metabolisme van een heel speciale bacterie, Streptomyces coelicolor. Het is een beroemd lid van een grote familie van bacteriën die antibiotica produceert en die gebruikt wordt om infectieziekten te bestrijden. Met nauwkeurige analytische technieken heeft Merlo gekeken hoe de chemische samenstelling van deze bacteriën (hun zogenaamde metabolomische profiel) verandert als ze blootgesteld worden aan verschillende vormen van metabole stress en verschillende omgevingen.
Voor het eerst toonde zij aan dat zo’n metabolomisch profiel waardevolle inzichten kan bieden over hoe een micro-organisme zijn hele cellulaire systeem kan herordenen om zich aan te kunnen passen aan moeilijke situaties. Omdat we weten dat antibiotica bij voorkeur geproduceerd worden in zulke omstandigheden (bijvoorbeeld om de bacterie te beschermen), kunnen deze resultaten nu gebruikt worden om nieuwe designer-micro-organismen te fabriceren om op een verbeterde manier antibiotica te produceren.
The scope of the thesis of Elena Merlo has been to explore the metabolism of a very special bacterium called Streptomyces coelicolor, a famous member of a large group of bacteria that produce antibiotics, which are used to treat such infectious diseases. Using high-performance analytical techniques, she assessed how these bacteria change their chemical composition (their so-called metabolome profile) in response to different stresses and environmental conditions. Merlo showed for the first time, that the metabolome profile can give valuable insights into how a microorganism rearranges its whole cellular system to adapt to challenging situations. As we know that antibiotics are preferentially produced in such circumstances (for example, to defend the bacterium), these results can now be used to create new designer microorganisms for the improved production of antibiotics.
Microorganisms play an important role in our lives: they are used in the large-scale preparation of bread, cheese, wine, beer, but also for producing many high-value chemical compounds such as drugs and biofuels. Moreover, huge numbers of bacteria and fungi grow in the human gut, where many of them help maintaining our health. At the same time, of course, microorganisms are responsible for widespread infectious diseases, such as tuberculosis.
Exploring the metabolism of Streptomyces coelicolor using mass spectrometry-based metabolomics
No full textMicro-organismen spelen een belangrijke rol in onze levens: ze worden gebruikt in de industriële productie van brood, kaas, wijn, en bier, maar ook van vele waardevolle chemische stoffen zoals medicijnen en biobrandstoffen. Bovendien leven er enorme aantallen bacteriën en schimmels in het menselijke darmstelsel, waar velen van hen helpen om onze gezondheid op peil te houden. Tegelijkertijd zijn micro-organismen natuurlijk ook verantwoordelijk voor wijdverbreide infectieziekten zoals tuberculose. In haar proefschrift beschrijft Elena Merlo een verkenning van het metabolisme van een heel speciale bacterie, Streptomyces coelicolor. Het is een beroemd lid van een grote familie van bacteriën die antibiotica produceert en die gebruikt wordt om infectieziekten te bestrijden. Met nauwkeurige analytische technieken heeft Merlo gekeken hoe de chemische samenstelling van deze bacteriën (hun zogenaamde metabolomische profiel) verandert als ze blootgesteld worden aan verschillende vormen van metabole stress en verschillende omgevingen. Voor het eerst toonde zij aan dat zo’n metabolomisch profiel waardevolle inzichten kan bieden over hoe een micro-organisme zijn hele cellulaire systeem kan herordenen om zich aan te kunnen passen aan moeilijke situaties. Omdat we weten dat antibiotica bij voorkeur geproduceerd worden in zulke omstandigheden (bijvoorbeeld om de bacterie te beschermen), kunnen deze resultaten nu gebruikt worden om nieuwe designer-micro-organismen te fabriceren om op een verbeterde manier antibiotica te produceren
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
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
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
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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