1,772 research outputs found
Versuch einer Theorie der Phosphor-Intoxikation
No full textvorgelegt von Rudolf Tischner ; Referent: Privatdozent Dr. RickerUniversität Rostock, Dissertation, 190
Early responses of Arabidopsis thaliana to infection by Verticillium longisporum
No full textArabidopsis thaliana roots were infected with Verticillium longisporum conidia in a sterile hydroponic culture. The phosphorylation pattern of root and shoot proteins was transiently changed within 10 min after contact with the conidia. A transient burst of NO was observed in the root area and may be a signal transferred to the shoot. When tested at 50 min after the first contact with the pathogen, the expression of 732 genes in the roots and 474 genes in the shoot (change >2 fold, p-value < 0.05) was affected. Genes related to cell wall synthesis, proteolysis and transcription were induced in the roots. Genes linked to signaling, proteolysis and defense were up-regulated. (C) 2010 Elsevier Ltd. All rights reserved
Interference with the citrulline-based nitric oxide synthase assay by argininosuccinate lyase activity in Arabidopsis extracts
No full textThere are many reports of an arginine-dependent nitric oxide synthase activity in plants; however, the gene(s) or protein(s) responsible for this activity have yet to be convincingly identified. To measure nitric oxide synthase activity, many studies have relied on a citrulline-based assay that measures the formation of L-citrulline from L-arginine using ion exchange chromatography. In this article, we report that when such assays are used with protein extracts from Arabidopsis, an arginine-dependent activity was observed, but it produced a product other than citrulline. TLC analysis identified the product as argininosuccinate. The reaction was stimulated by fumarate (> 500 microM), implicating the urea cycle enzyme argininosuccinate lyase (EC 4.3.2.1), which reversibly converts arginine and fumarate to argininosuccinate. These results indicate that caution is needed when using standard citrulline-based assays to measure nitric oxide synthase activity in plant extracts, and highlight the importance of verifying the identity of the product as citrulline.Rudolf Tischner, Mary Galli, Yair M. Heimer, Sarah Bielefeld, Mamoru Okamoto, Alyson Mack and Nigel M. Crawfor
Testing for terrestrial and freshwater microalgae productivity under elevated CO2 conditions and nutrient limitation
No full textAbstract Background Microalgae CO2 fixation results in the production of biomass rich in high-valuable products, such as fatty acids and carotenoids. Enhanced productivity of valuable compounds can be achieved through the microalgae’s ability to capture CO2 efficiently from sources of high CO2 contents, but it depends on the species. Culture collections of microalgae offer a wide variety of defined strains. However, an inadequate understanding of which groups of microalgae and from which habitats they originate offer high productivity under increased CO2 concentrations hampers exploiting microalgae as a sustainable source in the bioeconomy. Results A large variety of 81 defined algal strains, including new green algal isolates from various terrestrial environments, were studied for their growth under atmospheres with CO2 levels of 5–25% in air. They were from a pool of 200 strains that had been pre-selected for phylogenetic diversity and high productivity under ambient CO2. Green algae from terrestrial environments exhibited enhanced growth up to 25% CO2. In contrast, in unicellular red algae and stramenopile algae, which originated through the endosymbiotic uptake of a red algal cell, growth at CO2 concentrations above 5% was suppressed. While terrestrial stramenopile algae generally tolerated such CO2 concentrations, their counterparts from marine phytoplankton did not. The tests of four new strains in liquid culture revealed enhanced biomass and chlorophyll production under elevated CO2 levels. The 15% CO2 aeration increased their total carotenoid and fatty acid contents, which were further stimulated when combined with the starvation of macronutrients, i.e., less with phosphate and more with nitrogen-depleted culture media. Conclusion Green algae originating from terrestrial environments, Chlorophyceae and Trebouxiophyceae, exhibit enhanced productivity of carotenoids and fatty acids under elevated CO2 concentrations. This ability supports the economic and sustainable production of valuable compounds from these microalgae using inexpensive sources of high CO2 concentrations, such as industrial exhaust fumes
Rudolf Otto filosofo della religione
No full textLo straordinario successo del Sacro (1917), che ha reso celebre Rudolf Otto, ha provocato, per contraccolpo, la diffusione di una figura stilizzata dell’autore, impoverita dall’oblio toccato al resto della sua produzione e da letture parziali e semplificative. Una ricostruzione genetica del modo in cui Otto impone la nozione di «heilig» nel lessico tedesco specializzato, muovendo da Lutero e opponendo al neokantismo una lettura friesiana del trascendentale, fa emergere la qualità filosofica di una teoria del religioso che rivela convergenze insospettate con la fenomenologia husserliana. The extraordinary success of The Holy (1917) made Rudolf Otto famous, but it also contributed to propagate a simplified figure of the author. The rest of his work was condemned to oblivion, which caused misleading interpretations of The Holy itself. A genetic reconstruction of the way in which Otto established the term «heilig» in the technical German proves to be fruitful. When considering his interpretation of Luther and his Fries-based opposition to a neoKantian approach to the concept of «transcendental», the philosophical relevance of Otto’s theory of religion can be fully recognized, as well as unsuspected links to Husserlian phenomenology
Nitrate reductase from winter wheat leaves is activated at low temperature via protein dephosphorylation
No full textThe effect of short-term low temperature treatment on nitrate reductase (NR, EC 1.6.6.1) activity, NR protein and NR transcript levels in excised leaves of winter wheat (Triticum aestivum L. cv. Sadovo-1) was investigated. NR activity, measured in the presence of Mg2+ (NRact), doubled within 2 h at 4degreesC, whereas NR activity, measured in the presence of EDTA (NRmax), did not respond to the cold treatment. Such an activation of NR occurred only if leaves were exposed to low temperature in the light but not in the dark. It was not affected by feeding cytoplasmic protein synthesis inhibitor, cycloheximide, or protein kinase inhibitor, staurosporin, but was completely prevented by okadaic acid, an inhibitor of protein phosphatases of the type 1 and 2 A. This inhibitory effect decreased gradually when okadaic acid-concentration in the nutrient solution was lowered below 1 muM and tended to disappear when leaves were fed with 10 nM okadaic acid. It was demonstrated that the cold-induced NR activation was dependent neither on cold-triggered calcium influx nor on high endogenous abscisic acid levels. The increased NRact in cold-exposed leaves was found to correlate with a higher level of NR transcript but not with an increased NR protein level. Feeding okadaic acid to these leaves prevented the cold-induced accumulation of NR mRNA. These data point to protein phosphatases of the type 2 A being involved in NR protein dephosphorylation and NR transcript accumulation as targets of activation by low temperature treatment
Rudolf Mayer
No full textThe bachelor thesis deals with the life and work of Rudolf Mayer. In the first part, attention is given to the author and the reception of his work presented in period magazines and newspapers from the poet´s death in 1945. During the second part of his work is examined in terms of literary discursivity the subjective romanticism
Rudolf Hilferding on English Mercantilism
No full textIn 1911 Rudolf Hilferding, the author of the famous book Finance Capital: A Study of the Latest Phase of Capitalist Development, published an article on the history of English mercantilism in Die neue Zeit, the theoretical organ of the Social Democratic Party of Germany edited by Karl Kautsky. The writing of the article was motivated by the publication, the previous year, of the third volume of Theories of Surplus-Value, containing Marx’s analysis of the work of Richard Jones, as well as by the simultaneous appearance of a German edition of Thomas Mun’s England’s Treasure by Forraign Trade. This article introduces the present author’s English translation of Hilferding’s article on mercantilism, titled “The Early Days of English Political Economy,” previously available only in German, and contextualizes it in the framework of the history of Marxist scholarship.Fil: Gaido, Daniel Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones y Estudios sobre Cultura y Sociedad. Universidad Nacional de Córdoba. Centro de Investigaciones y Estudios sobre Cultura y Sociedad; Argentin
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