1,721,547 research outputs found
Role of the Mn-Catalase in Aerobic Growth of Lactobacillus plantarum ATCC 14431
No full textLactobacilli are Gram-positive aerotolerant organisms that comprise the largest genus of Lactic Acid Bacteria (LAB). Most lactobacilli are devoid of the antioxidant enzymes, superoxide dismutases, and catalases, required for protection against superoxide radicals and hydrogen peroxide (H2O2), respectively. However, some lactobacilli can accumulate millimolar concentrations of intracellular manganese and spare the need for superoxide dismutase, while others possess non-heme catalases. L. plantarum is associated with plant materials and plays an important role in fermented foods and gut microbiomes. Therefore, understanding the effects of the environment on the growth and survival of this organism is essential for its success in relevant industrial applications. In this report, we investigated the physiological role of Mn-catalase (MnKat) in Lactobacillus plantarum ATCC 14431. To this end, we compared the physiological and morphological properties of a ΔMnkat mutant strain and its isogenic parental strain L. plantarum ATCC 14431. Our data showed that the MnKat is critical for the growth of L. plantarum ATCC 14431 in the presence of oxygen and resistance to H2O2. The aerobic growth of the mutant in presence or absence of H2O2 was improved in the Mn-rich medium (APT) as compared to the growth in MRS medium. Furthermore, under aerobic conditions the mutant strain possessed atypical cellular morphology (i.e., shorter, and fatter). In conclusion, the MnKat of L. plantarum ATCC 14431 is important for aerobic growth, protection against H2O2, and maintenance of the rod-shaped cell morphology under aerobic conditions
The influence of intravenous vs. intraperitoneal application of emodin and BTB 14431 on advanced intra- and extraperitoneal tumor growth in rats
No full textZur Therapie des Kolorektalen Karzinoms gibt es zahlreiche neue Präparate auf
dem Markt, die jedoch häufig Resistenzen und Nebenwirkungen zeigen. Auf der
Suche nach neuen pharmakologischen Substanzen mit verbesserten Eigenschaften
wurde in vorhergehenden Experimenten mittels des Kinase-Inhibitors Emodin eine
neue Substanz (BTB 14431) durch ein in silico Screening entdeckt und bereits
einmalig in vivo in einem Tumorsuspensionsmodell untersucht. Verschiedene
Studien zeigten, dass Emodin Apoptose induziert, Zellproliferation hemmt sowie
Angiogenese unterbindet und somit Tumorwachstum reduzieren kann. In dem hier
vorgestellten Tierexperiment wurde nun der Einfluss von Emodin und BTB 14431
auf das Wachstum von fortgeschrittenen Tumoren in Hinblick auf Unterschiede in
der Applikationsart und der Dosierung untersucht. Es wurde ein
standardisiertes tierexperi-mentelles Tumormodell etabliert und zunächst die
Freisetzung vitaler Tumorzellen durch einen onkotischen Eingriff simuliert.
Hierzu erhielten 100 Ratten (WAG-RIJ) eine sterile intraperitoneale Injektion
von 105 syngenetischen Kolonadenokarzinomzellen (CC-531) mittels Laparotomie.
Außerdem erhielten die Tiere eine subkutane Zellinjektion von ebenfalls 105
syngenetischen Tumorzellen des gleichen Zelltyps, die periphere Metastasen
simulieren sollten. Um den systemischen Einflusses der neu identifizierten
Substanz BTB 14431 sowie von Emodin auf solide Tumoren zu untersuchen, wurde
die Hälfte der Tiere 28 Tage nach Zellapplikation mittels Ports in der Vena
jugularis externa über eine Woche in einem 12-stündigen Rhythmus behandelt
(Kontrollgruppe: Behandlung mit Ringer-Laktat, Therapiegruppen: Behandlung mit
0,3 mg/kg KG BTB 14431, 1,7 mg/kg KG BTB 14431, Emodin 2,5 mg/kg KG oder
Emodin 5 mg/kg KG). Die andere Hälfte der Tiere erhielt die intermittierende
Therapie über intraperitoneale Injektionen. Drei Wochen nach Behandlungsende
wurden die Tiere euthanasiert und die Tumorgewichte bestimmt. In diesem
Experiment konnte ein dosisabhängiger Einfluss von Emodin und BTB 14431 auf
das Wachstum der Tumoren gezeigt werden. Dabei schien Emodin potenter und
besser verträglich zu sein als BTB 14431. Dies ist jedoch sowohl von der Dosis
als auch von der Applikationsart abhängig. Die besten Ergebnisse zeigten die
Gruppen, die Emodin in einer der beiden Dosierungen oder BTB 14431 in der
Dosierung 0,3 mg/kg KG intravenös erhielten. Die Tiere dieser Gruppen nahmen
mehr an Körpergewicht zu und die Tumore hatten ein geringeres Gewicht als bei
der Kontrollgruppe. Des Weiteren konnte bei den genannten Gruppen eine bessere
Wirksamkeit der Behandlung bei intravenöser Applikation im Vergleich zur
intraperitonealen Applikation festgestellt werden. Bei den intraperitoneal
behandelten Tieren gab es lediglich bei der Behandlung mit 5 mg/kg KG Emodin
einen Unterschied im Gewicht der Tumormassen zur Kontrollgruppe. BTB 14431
zeigte bei höherer Dosierung nicht den erwarteten Effekt.For the treatment of colorectal cancer many new products are on the market,
but often with drug resistance and side effects. Looking for new
pharmacological agents with improved properties, a new substance (BTB 14431)
was discovered by using the kinase inhibitor emodin and “in silico screening”.
It was already examined once in vivo in a tumor suspension model in a previous
experiment. Various studies have shown that emodin induces apoptosis, inhibits
cell proliferation and suppresses angiogenesis and so may reduce tumor growth.
In this experimental study the effect of emodin and BTB 14431 on the growth of
advanced tumors with relation to differences in the mode of application and
the dosage has now been investigated. A standardized animal model of cancer
has been established and the release of vital tumor cells by an oncotic
intervention was simulated. For this purpose 100 rats (WAG RIJ) received a
sterile intraperitoneal injection of 105 syngenetic colon adenocarcinoma cells
(CC-531) by laparotomy. In addition, the animals were given a subcutaneous
injection of also 105 syngenetic tumor cells of the same cell type, which
should simulate peripheral metastases. To investigate the systemic influence
of the newly identified substance BTB 14431 and of emodin to solid tumors half
of the animals were treated by ports in the external jugular vein over a week
in a 12-hour rhythm 28 days after cellapplication (control group: treatment
with Ringer’s solution, treatment groups: treatment with 0,3 mg/kg bw BTB
14431, 1,7 mg/kg bw BTB 14431, emodin 2,5 mg/kg bw or emodin 5 mg/kg bw). The
other half of the animals received intraperitoneal injections of the
intermittent therapy. Three weeks after treatment, the animals were euthanized
and the tumor weights were determined. As a result of this experiment, a dose-
dependent effect of emodin and BTB 14431 on the growth of tumors could be
shown. Moreover, emodin seems to be more potent and better tolerated than BTB
14431. However, this is dependent on both the dose and the mode of
application. The best results were shown in the groups with intravenous emodin
treatment in one of the dosages or BTB 14431 0,3 mg/kg. The animals in this
group increased more in weight and the tumors had a lower weight than in the
control group. Furthermore, a better efficacy of treatment for intravenous
application was observed in the mentioned groups as compared to the
intraperitoneal application. In the groups with animals treated
intraperitoneally there was only a difference in the weight of the tumor mass
compared to the control group treated with 5 mg/kg KG emodin. BTB 14431 did
not show the expected effect at higher doses
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
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
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