Metabolic Fingerprinting an Rhizoctonia solani (Kühn)

Der Basidiomycet Rhizoctonia solani (Kühn) ist ein weltweit verbreiteter Bodenpilz, welcher an zahlreichen Kulturen zu erheblichen Ertragsverlusten führen kann. Aufgrund des breiten Wirtspflanzenkreises und der sowohl parasitischen als auch saprophytischen Lebensweise ist der Erreger speziell im ökologischen Landbau sehr schwer bekämpfbar. Zum besseren Verständnis der Wirt-Pathogen-Interaktion wurden zahlreiche anwendungsbezogene Studien zur Biologie des Erregers, der chemischen Bekämpfung, dem Einfluss der Bodenbearbeitung der Fruchtfolge und der Sortenwahl durchgeführt (Bolton et al., 2010). Ergänzt wurden diese Untersuchungen durch Arbeiten zur Genexpression unbekannter Proteine und Enzyme des primären und sekundären Stoffwechsels (Zheng et al. 2015) sowie zur Expression anastomosegruppenspezifischer Primärmetaboliten (Aliferis et al. 2013). Hierauf aufbauend wurden am Fachgebiet Bodenbiologie und Pflanzenernährung erste Untersuchungen zur metabolischen Variabilität an insgesamt 35 Isolaten unterschiedlicher Anastomosegruppen durchgeführt. Hierbei konnten mittels HPLC-CAD Kopplung mehrere anastomosegruppenspezifische Metabolite detektiert und quantifiziert werden. Das Metabolitenmuster innerhalb verschiedener Isolate einer AG war hingegen vergleichbar. Derzeit laufende Untersuchungen zur biologischen Aktivität der untersuchten Extrakte sollen ferner Aufschluss über die Funktion der gebildeten Metaboliten liefern

Ullemar's formula for the Jacobian of the complex moment mapping

The complex moment sequence m(P) is assigned to a univalent polynomial P by the Cauchy transform of the P(D), where D is the unit disk. We establish the representation of the Jacobian det dm(P) in terms of roots of the derivative P'. Combining this result with the special decomposition for the Hurwitz determinants, we prove a formula for the Jacobian which was previously conjectured by C. Ullemar. As a consequence, we show that the boundary of the class of all locally univalent polynomials in $U$ is contained in the union of three irreducible algebraic surfaces.Comment: 14 pages, submitted for "Complex Variables. Theory and Application

The politics and aesthetics of commemoration: national days in southern Africa

The contributions to the special section in this issue study recent independence celebrations and other national days in South Africa, Namibia, Zimbabwe, Madagascar and the Democratic Republic of Congo. They explore the role of national days in state-making and nation-building, and examine the performativity of nationalism and the role of performances in national festivities. Placing the case studies in a broader, comparative perspective, the introduction first discusses the role of the state in national celebrations, highlighting three themes: firstly, the political power-play and contested politics of memory involved in the creation of a country’s festive calendar; secondly, the relationship between state control of national days and civic or popular participation or contestation; and thirdly, the complex relationship between regional and ethnic loyalties and national identifications. It then turns to the role of performance and aesthetics in the making of nations in general, and in national celebrations in particular. Finally, we look at the different formats and meanings of national days in the region and address the question whether there is anything specific about national days in southern Africa as compared to other parts of the continent or national celebrations world-wide.Web of Scienc

Vertrauen, Zuversicht, Verführung, Distanz: Die Verteilungskoalitionen in Nepal an der Schnittstelle zwischen Staat und Bürger

Pfaff-Czarnecka J. Vertrauen, Zuversicht, Verführung, Distanz: Die Verteilungskoalitionen in Nepal an der Schnittstelle zwischen Staat und Bürger. In: Kössler R,, Neubert D, v. Oppen A, eds. Gemeinschaften in einer entgrenzten Welt. Studien des Zentrums Moderner Orient, Bd. 12. Berlin: Das Arabische Buch; 1999: 83-111

Expression of a carotenogenic gene allows faster biomass production by redesigning plant architecture and improving photosynthetic efficiency in tobacco

Summary Because carotenoids act as accessory pigments in photosynthesis, play a key photoprotective role, and are of major nutritional importance, carotenogenesis has been a target for crop improvement. Although carotenoids are important precursors of phytohormones, previous genetic manipulations reported little if any effects on biomass production and plant development, but resulted in specific modifications in carotenoid content. Unexpectedly, the expression of the carrot lycopene b-cyclase (DcLCYB1) in Nicotiana tabacum cv. Xanthi not only resulted in increased carotenoid accumulation, but also in altered plant architecture characterized by longer internodes, faster plant growth, early flowering and increased biomass. Here, we have challenged these transformants with a range of growth conditions to determine the robustness of their phenotype and analyze the underlying mechanisms. Transgenic DcLCYB1 lines showed increased transcript levels of key genes involved in carotenoid, chlorophyll, gibberellin (GA) and abscisic acid (ABA) biosynthesis, but also in photosynthesis-related genes. Accordingly, their carotenoid, chlorophyll, ABA and GA contents were increased. Hormone application and inhibitor experiments confirmed the key role of altered GA/ABA contents in the growth phenotype. Because the longer internodes reduce shading of mature leaves, induction of leaf senescence was delayed, and mature leaves maintained a high photosynthetic capacity. This increased total plant assimilation, as reflected in higher plant yields under both fully-controlled constant and fluctuating light, and in non-controlled conditions. Furthermore, our data is a warning that engineering of isoprenoid metabolism can cause complex changes in phytohormone homeostasis and therefore plant development, which have not been sufficiently considered in previous studies