514 research outputs found

    Farbe bekennen : Goethes Farbenlehre und die Berliner Wissenschaftspolitik um 1820

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    Hier [soll] nicht ein weiteres Mal das bekannte Fiasko der Farbenlehre beschworen, sondern umgekehrt ihre Erfolgsgeschichte nachgezeichnet werden

    Synthesis and hydrolysis of auxins and their conjugates with different side-chain lengths: are all products active auxins?

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    Plants need hormone substances to regulate a plethora of responses during their life cycle. One major hormone class is called auxin, which is involved in many developmental processes. Besides the major auxin indole-3-acetic acid, there are other auxin-like molecules present in some, but not in all plants, an example would be chlorinated IAA in legumes. Among these are also the auxins with longer chains, indole-3-propionic acid and indole-3-butyric acid. The auxin-dependent growth response is dependent on the concentration of the compound. While lower concentrations are mainly growth promoting, high concentrations are actually inhibiting some developmental processes. Therefore, tight control of the auxin concentration is essential for proper growth and development. This can be achieved by altering the amount of active auxin via transport, biosynthesis, degradation or reversible conjugation to small molecules. In addition, plants use auxin during their interaction with the environment, for example during abiotic stresses such as salt, temperature or water stress to adapt the growth responses specifically. Furthermore, auxin is involved in the development of plant disease symptoms, such as tumor growth or aberrant tissue formation. However, together with other plant hormones such as salicylic acid auxin can also modulate disease progression or resistance in different plant – microbe combinations. </p

    Von sich selbst erzählen und miteinander sprechen als Spiegel und Promotor lebensgeschichtlicher Strukturen - ein strukturanalytischer Forschungszugang und seine möglichen Implikationen für Supervisionspraxis und Supervisionsfortbildung

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    Der erste Teil des vorliegenden Beitrags ist dem Verhältnis von Erzählen, Interagieren und biografischer Struktur gewidmet und gibt einen Einblick in die Forschung der Autorin in diesem Bereich auf der Grundlage von struktural-rekonstruktiven Analysen. Im zweiten Teil tritt die Autorin für eine stärkere Verzahnung solcher Forschungsansätze mit der Supervisorischen Praxis ein und zeigt den möglichen Nutzen anhand von eigenen Erfahrungen auf

    Management und Quantenphysik. Das Beispiel TELE

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    Die Managementpraxis ist immer noch stark vom Weltbild der klassischen Physik und damit von Reduktionismus, Determinismus und Positivismus geprägt. Ziel dieses Beitrages ist am Beispiel der Wiener Firma TELE zu illustrieren, wie das Paradigma der Quantenphysik in einer Zeit, die durch schnelle Veränderungen und unvorhersehbare Unternehmensumwelten gekennzeichnet ist, Management inspirieren kann. Nach einer kurzen Einführung in die klassische Physik, werden am Beispiel der quantenphysikalischen Phänomene Welle-Teilchen Dualismus, Heisenbergsche Unschärferelation und Feldtheorie Aspekte eines daran orientierten Quantenmanagement illustriert

    Auxin Amidohydrolases – From Structure to Function: Revisited

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    The control of plant growth and development is a well-coordinated process between exogenous and endogenous signals. Auxins are plant hormones belonging to the endogenous signals, which control a vast array of different processes. While auxins are growth promoting at low concentrations, higher levels are often inhibitory. Therefore, the tight control of auxin concentrations in a given plant tissue is essential. Among several processes that participate in auxin homeostasis, we focused herein on the process of reversible auxin conjugation that considers the synthesis of inactive auxin conjugates, which can be hydrolyzed back to the active form by so called auxin conjugate hydrolases. Although these proteins have been known for quite some time, their role in plants is still not clear, especially since novel hydrolases with different substrate specificities have been isolated. Thus, we have revisited the knowledge about auxin hydrolases, from their structure and biochemistry to the role in plant development and in dealing with unfavorable climate conditions. This work is licensed under a Creative Commons Attribution 4.0 International License

    High-level expression of a viscotoxin in Arabidopsis thaliana gives enhanced resistance against Plasmodiophora brassicae

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    Viscotoxins are a group of toxic thionins found in several mistletoe species. The constitutive CaMV-Ω promoter was used to drive the expression of the viscotoxin A3 cDNA from Viscum album in transgenic Arabidopsis thaliana C24. Lines with high viscotoxin A3 levels in all parts of the plant were selected and tested for resistance against the clubroot pathogen Plasmodiophora brassicae. The transgenic lines were more resistant to infection by this pathogen than the parental lin

    Manufacture, use and management of macro-lithic resources in the Bronze Age settlement of Bruszczewo (Poland)

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    Contrary to pottery or metal artefacts, macro-lithic tools are still not fully integrated into the archaeological research programs concerning the Early Bronze Age of Central Europe. While such kind of archaeological materials usually do not easily allow typological approaches, their constant participation in several productive spheres makes them a crucial element for understanding the economic processes and the organisation of past societies. This paper presents the general results of the investigation carried out on an assemblage of 1073 macro-lithic items recovered in the wet soil area of the site of Bruszczewo (municipality of Śmigiel, Poland). This fortified settlement was inhabited during the Early Bronze Age (2100-1650 BCE) and later on in the Late Bronze Age and Early Iron Age (1100-800 BCE), with minor archaeological evidences from Middle Ages. The methodology applied in this assessment is a holistic one, which combines manufacturing (petrography and morphometry), functional (use-wear and residues) and spatial analyses. This approach has allowed recording a mainly local raw material supplying system, based on the gathering of pebbles in the vicinity of the site and a minimal transformation of raw pieces previous to use. Moreover, Bruszczewo comes out to be a central settlement managing and controlling exogenous ores, such as copper and gold, as shown by residues found on some macro-lithic forging anvils. All in all, the recognition in the macro-lithic tool assemblage of different tasks related to subsistence (food preparation) as well as to manufacture (metallurgy, probably bone working) processes contributes to (a) defining the settlement's organisation and the management of resources in the site and (b) improving our understanding of the role played by central settlements in the socio-economic networks, at a time when the first class societies emerged in Central Europe

    A Novel Target (Oxidation Resistant 2) in Arabidopsis thaliana to Reduce Clubroot Disease Symptoms via the Salicylic Acid Pathway without Growth Penalties

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    The clubroot disease (Plasmodiophora brassicae) is one of the most damaging diseases worldwide among brassica crops. Its control often relies on resistant cultivars, since the manipulation of the disease hormones, such as salicylic acid (SA) alters plant growth negatively. Alternatively, the SA pathway can be increased by the addition of beneficial microorganisms for biocontrol. However, this potential has not been exhaustively used. In this study, a recently characterized protein Oxidation Resistant 2 (OXR2) from Arabidopsis thaliana is shown to increase the constitutive pathway of SA defense without decreasing plant growth. Plants overexpressing AtOXR2 (OXR2-OE) show strongly reduced clubroot symptoms with improved plant growth performance, in comparison to wild type plants during the course of infection. Consequently, oxr2 mutants are more susceptible to clubroot disease. P. brassicae itself was reduced in these galls as determined by quantitative real-time PCR. Furthermore, we provide evidence for the transcriptional downregulation of the gene encoding a SA-methyltransferase from the pathogen in OXR2-OE plants that could contribute to the phenotype.Fil: Mencia, Regina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; ArgentinaFil: Welchen, Elina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; ArgentinaFil: Auer, Susann. Technische Universität Dresden; AlemaniaFil: Ludwig Müller, Jutta. Technische Universität Dresden; Alemani

    Genetically transformed roots: From plant disease to biotechnological resource

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    Hairy root syndrome is a disease that is induced by Agrobacterium rhizogenes infection and characterized by a proliferation of excessively branching roots. However, in the past 30 years A. rhizogenes-mediated transformation has also provided a valuable platform for studying biosynthesis pathways in plants. Furthermore, the genetically transformed root cultures are becoming increasingly attractive, cost-effective options for mass-producing desired plant metabolites and expressing foreign proteins. Numerous proof-of-concept studies have demonstrated the feasibility of scaling up hairy-root-based processes while maintaining their biosynthetic potential. Recently, hairy roots have also shown immense potential for applications in phytoremediation, that is, plant-based decontamination of polluted environments. This review highlights recent progress and limitations in the field, and outlines future perspectives for the industrial exploitation of hairy roots.Fil: Georgiev, Milen I.. Bulgarian Academy of Sciences; Bulgaria. Leiden University; Países BajosFil: Agostini, Elizabeth. Universidad Nacional de Río Cuarto; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Ludwig Müller, Jutta. Technische Universitat Dresden; AlemaniaFil: Xu, Jianfeng. University of Arkansas for Medical Sciences; Estados Unido
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