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Editorial: Regulation of proteostasis and cellular energy homeostasis at the primary cilium
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The effects of enhanced ozone and enhanced carbon dioxide concentrations on biomass, pigments and antioxidative enzymes in spruce needles (Picea abies L.)
No full textDuring one growing period, 5‐year‐old spruce trees (Picea abies L., Karst.) were exposed in environmental chambers to elevated concentrations of carbon dioxide (750 cm3 m−3) and ozone (008 cm3 m−3) as single variables or in combination. Control concentrations of the gases were 350cm3 m−3CO2 and 0.02 cm3 m −3 ozone. To investigate whether an elevated CO2 concentration can prevent adverse ozone effects by reducing oxidative stress, the activities of the protective enzymes superoxide dismutase, catalase and peroxidase were determined. Furthermore, shoot biomass, pigment and protein contents of two needle age classes were investigated. Ozone caused pigment reduction and visible injury in the previous year's needles and growth reduction in the current year's shoots. In the presence of elevated concentrations of ozone and CO2, growth reduction in the current year's shoots was prevented, but emergence of visible damage in the previous year's needles was only delayed and pigment reduction was still found. Elevated concentrations of ozone or CO2 as single variables caused a significant reduction in the activities of superoxide dismutase and catalase in the current year's needles. Minimum activities of superoxide dismutase and catalase and decreased peroxidase activities were found in both needle age classes from spruce trees grown at enhanced concentrations of both CO2 and ozone. These results suggest a reduced tolerance to oxidative stress in spruce trees under conditions of elevated concentrations of both CO2 and ozone
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
The GID-complex is a novel ubiquitin ligase involved in the regulation of adenosine monophosphate-activated protein kinase (AMPK) and the function of the primary cilium : [kumulative Dissertation]
No full textDie AMP-aktivierte Proteinkinase (AMPK) reguliert die zelluläre Energiehomöostase, indem der metabolische Status der Zelle erfasst wird. AMPK wird durch Phosphorylierung und Dephosphorylierung als Ergebnis der Änderung der ADP/ATP- und AMP/ATP-Spiegel und durch Entfernung von inhibierenden Ubiquitinresten durch USP10 reguliert. In diesem Zusammenhang haben wir den GID-Komplex, einen evolutionär konservierten Ubiquitin-Ligase-Komplex (E3), als negativen Regulator der AMPK-Aktivität identifiziert. Unsere Daten zeigen, dass der GID-Komplex die AMPK ubiquitiniert und dadurch ihre Aktivität verändert. Zellen, die in GID-Untereinheiten depletiert sind, ahmen einen Zustand des Hungerns nach, was durch erhöhte AMPK-Aktivität und autophagischen Fluss sowie eine verringerte mTOR-Aktivierung gezeigt wird. In C. elegans führt der Knockdown von gid-Genen zu einer erhöhten Lebensdauer von Organismen. Diese Studie kann zum Verständnis von Stoffwechselstörungen wie Diabetes mellitus Typ 2 und krankhafter Fettleibigkeit beitragen und trägt alternative therapeutische Ansätze zur Änderung der AMPK-Aktivität bei. Zusätzlich fanden wir, dass sich der GID-Komplex teilweise am Basalkörper des primären Ziliums befindet. Funktionsverlust des GID-Komplex schwächt die Reaktion des Sonic Hedgehog Signalwegs ab und gibt uns eine neue Vorstellung über einen möglichen Mechanismus der SHH-Signal-Ziliopathien.The AMP-activated protein kinase (AMPK) regulates cellular energy homeostasis by sensing the metabolic status of the cell. AMPK is regulated by phosphorylation and dephosphorylation as a result of changing ADP/ATP and AMP/ATP levels and by removal of inhibitory ubiquitin residues by USP10. In this context, we identified the GID-complex, an evolutionarily conserved ubiquitin-ligase-complex (E3), as a negative regulator of AMPK activity. Our data show that the GID-complex targets AMPK for ubiquitination thereby altering its activity. Cells depleted of GID-subunits mimic a state of starvation as shown by increased AMPK activity and the downstream autophagic flux. Consistently, gid-genes knockdown in C. elegans results in increased organismal lifespan. This study may contribute to understand metabolic disorders like type 2 diabetes mellitus and morbid obesity and implements alternative therapeutic approaches to alter AMPK activity. In addition, we found that the GID-complex partially localizes at the basal body of primary cilia. Loss-of-function of the GID-complex attenuates the response of Sonic Hedgehog signaling pathway, giving us a novel idea about the potential mechanism of SHH signal related ciliopathies
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
The role of the GID complex at the primary cilium
Get PDFThe primary cilium acts as a signalling hub for many important pathways, including the Hedgehog signalling pathway (Hh). Sonic hedgehog (Shh) can be activated via the canonical signalling route, involving proteins of the GLI family, which localise to the primary cilium. A study by Boldt et al. located the mammalian homologue to the GID complex in close proximity to the primary cilium. The GID complex was first discovered in Saccharomyces cerevisiae. However, little is known about the mammalian GID complex and the roles it plays, especially regarding primary cilia. In summary, this thesis underscores the interplay between the primary cilia and the GID complex in mammalian cells. Additionally, four subunits of the GID complex were shown to localise to the primary cilia, further strengthening the hypothesis of an intricate relationship between these two players. Lastly, putative novel interacting partners for GID4 could be proposed.Das primäre Cilium fungiert als Signalknotenpunkt für viele wichtige Signalwege, einschließlich des Hedgehog-Signalwegs (Hh). Sonic Hedgehog (Shh) kann über den kanonischen Signalweg aktiviert werden, an dem Proteine der GLI-Familie beteiligt sind, die im primären Zilium lokalisiert sind. Eine Studie von Boldt et al. lokalisierte das Säuger-Homolog zum GID-Komplex in unmittelbarer Nähe des primären Ziliums. Der GID-Komplex wurde zuerst in Saccharomyces cerevisiae entdeckt, über den Säugetier-GID-Komplex und die Rolle, die er spielt, ist wenig bekannt. Zusammenfassend unterstreicht diese Arbeit das Zusammenspiel zwischen den primären Zilien und dem GID-Komplex in Säugetierzellen. Darüber hinaus wurde gezeigt, dass sich vier Untereinheiten des GID-Komplexes an den primären Zilien lokalisieren, was die Hypothese einer komplizierten Beziehung zwischen diesen beiden Akteuren weiter stärkt. Schließlich konnten mutmaßliche neuartige Interaktionspartner für GID4 vorgeschlagen werden
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
Nikotinamidadenindinukleotid-Blutplasmawerte sind unabhängig vom kalendarischen und vaskulären Alter in einer Normalkohorte aus der Region Halle-Saalekreis
Get PDFNikotinamidadenindinukleotid (NAD) ist beteiligt an Stoffwechsel- und Signalwegen. Die intrazelluläre Wirkung ist bekannt, weniger weiß man über die extrazelluläre NAD-Wirkung. Daher untersuchten wir in unsere Studie NAD im Blutplasma abhängig von Geschlecht und Alter. Die NAD-Werte im Plasma wurden bei 209 Probanden gemessen. Die total NAD Konzentration lag bei 1,34 μM (0,44 – 2,88 μM). Obwohl die Mengen an NAD+ und NADH gleichmäßig waren, hatten Frauen eine höhere NAD+/NADH Ratio als Männer (Median 1.33 vs. 1.09, P < 0.001). Die geschlechtsspezifischen Unterschiede in der Ratio verschwanden mit zunehmenden Alter, was deutlicher für zwei biologische Altersmarker (Pulswellengeschwindigkeit, Autofluoreszenz der Haut) zutraf als für das kalendarische Alter. Resümierend enthält das humane Plasma geringe Mikromolar an NAD mit einer höheren Ratio bei Frauen, aber nicht bei älteren Frauen im Vergleich zu gleichaltigen Männern.Nicotinamide adenine dinucleotide (NAD) is involved in metabolic reactions and signaling pathways. The intracellular function of NAD is well described, less is known about its extracellular function. Therefore, our study aimed at the analysis of NAD in human plasma depending on sex and age. Plasma NAD was analyzed in 209 probands without severe diseases. The total NAD concentration was determined with median 1.34 μM (0.44 – 2.88 μM). Although the amounts of NAD+ and NADH were nearly balanced, women had higher NAD+/NADH ratios than men (median 1.33 vs. 1.09, P < 0.001). The sex-related difference in the NAD+/NADH ratio reduces with increasing age, which was more obvious for two parameters of the biological age (skin autofluorescence, pulse wave velocity) than for the chronological age. In conclusion, human plasma contains low micromolar of total NAD with higher NAD+/NADH ratios in women but not older women compared with older men
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