Regulation of heterochromatic RNA decay via heterochromatin protein 1 (HP1)

The central dogma of molecular biology describes the directional flow of biological information from DNA via RNA to protein. Information stored in DNA is copied to an mRNA molecule during the process of transcription. The mRNA is used as a template for translation, in which polypeptides are synthesized. The regulation of this process, which is conserved through all trees of life, has been a central field of study over the last decades. The discovery that RNA not only serves a simple role as a mere copy, but is much more versatile has created a lot of excitement. For example, RNA molecules themselves can act as enzymes. In the ribosome, rRNAs comprise the catalytic core for peptide bond formation. snRNAs form the core of the splicing machinery. tRNAs are the adaptors and thereby the actual readers of the genetic code. Last but not least, in the RNAi pathway, small RNAs serve as guides to target silencing complexes to complementary RNAs. Altogether, these findings placed RNA at the center of eukaryotic genome regulation. On the other hand, DNA in eukaryotic cells does not exist as a mere fibre, but is wrapped around the core histone octamer to form a nucleosome. Nucleosomes are the basic building blocks to form higher order chromatin structures. Besides its architectural role in chromosome segregation, genome stability and recombination, chromatin has also been linked to gene expression. In contrast to the rather gene-rich euchromatin, heterochromatin is a highly condensed and repressive structure, serves as a safe storage place for transposable elements and makes up a large fraction of the genome of higher eukaryotes. Repression or activation in different chromatin contexts involves covalent modifications on the histone proteins. The nature and combination of these modifications create different docking sites for various effector proteins that have either activating or repressing function. Surprisingly, recent studies have suggested that a substantial fraction of the genome, although heterochromatic, is transcribed at least to a certain extent and many of those transcripts do not encode proteins. Moreover, fascinating mechanisms have been discovered, in which the silencing of heterochromatic sequences involves RNA-dependent mechanisms. Altogether this suggests that the regulation of the genomic output in eukaryotes not only occurs at the level of transcription but to a substantial extent via co- or posttranscriptional gene silencing mechanisms (CTGS or PTGS, respectively). The cellular RNA decay machineries therefore have to be equipped with tools to specifically distinguish and degrade certain RNAs. Generally, RNA decay mechanisms recognize aberrant features that are contained in the RNA molecule itself, for example the presence and length of a poly(A) tail at the 3’end. The RNAi pathway is triggered by the presence of short ssRNA molecules that are complementary to a target RNA and thereby lead to degradation. In some cases degradation induces feedback mechanisms back to chromatin resulting in histone modification and/or transcriptional modulation. My work has identified a novel mechanism to regulate RNA decay, which is dependent on the chromatin context from which the RNA has been transcribed. This mechanism is independent of the actual RNA sequence/molecule but involves binding to the heterochromatin protein HP1(Swi6). I found that HP1(Swi6) binding to a heterochromatic transcript fulfils a checkpoint function, which mediates repression on at least two levels. First, HP1(Swi6) prevents translation of heterochromatic RNA by inhibiting association with ribosomes. This ensures repression even in the absence of RNA decay. Second HP1(Swi6) mediates elimination by capturing RNA at the site of transcription and escorting it to the degradation machinery. On a molecular level, this is achieved by RNA binding to the HP1(Swi6) hinge region. This renders the chromodomain structurally incompatible with stable H3K9me association leading to heterochromatin eviction and degradation of the RNA. My data points towards a model in which binding of HP1(Swi6) to a heterochromatic RNA creates a heterochromatin-specific ribonucleoprotein (hsRNP) that is prone to degradation. Importantly, HP1(Swi6) can induce degradation of any RNA of heterochromatic origin, which could be a crucial feature to repress the expression of deleterious sequences and transposons. Last but not least, my work is the first example that demonstrates that RNAs can act as “repellents” for chromatin proteins

Field efficacy of entomopathogenic fungi to control Rhagoletis cerasi

Die Kirschfruchtfliege Rhagoletis cerasi Loew (Diptera: Tephritidae) ist der wichtigste Schädling im Süßkirschenanbau in Europa. Bei unbehandelten Bäumen können bis zu 100% der Kirschen Madenbefall aufweisen. Da Handel und Verbraucher nur einen Befall von maximal 2% tolerieren, sind effiziente Bekämpfungsmaßnahmen gefragt. Der bisher verwendete Wirkstoff Dimethoate könnte im Zuge der Re-Evaluation von Pflanzenschutzmitteln in der EU seine Zulassung verlieren. Danach stünde die gesamte Kirschenproduktion in Europa vor der gleichen Situation wie derzeit der ökologische Landbau: eine Regulierung der Kirschfruchtfliege wäre nur noch über Leimfallen oder durch den Einsatz von Netzen möglich. Beide Methoden sind sehr arbeitsintensiv und oft nicht ausreichend wirksam. Im Labor wurden mehrere Pilzstämme gegen verschiedene Entwicklungsstadien der Kirschfruchtfliege geprüft, mit dem Ergebnis, dass nur adulte Fliegen befallen werden. Dabei zeigten die Pilze Beauveria bassiana und Paecilomyces fumosoroseus die beste Wirkung. Diese beiden Pilze, die bereits in kommerziellen Produkten formuliert sind, wurden 2006 in zwei Feldversuchen gegen adulte Kirschfruchtfliegen appliziert.Two myco-insecticides, Naturalis-L (Beauveria bassiana) and PreFeRal®WG (Paecilomyces fumosoroseus), were applied against adult R. cerasi Loew (Diptera: Tephritidae) in two orchards in north-western Switzerland in summer 2006. Both products were able to cause mycosis on adult flies under field conditions. However, only Naturalis-L significantly reduced the number of damaged fruits (efficacy: 69-74%), whereas damaged fruits were not significantly reduced with PreFeRal (efficacy: 27%). For B. bassiana living fungal propagules were still detectable seven days after application while the fungal propagules of P. fumosoroseus remained only three days. A control of R. cerasi with myco-insecticides seems possible under field conditions; however, the application regime still has to be improved

Wirkungsanalyse von Bauvorhaben auf Gemeindefinanzen

Vielen Gemeinden fehlen Kenntnisse und Werkzeuge, um die Auswirkung geplanter Bauvorhaben auf Steuereinnahmen sowie Ausgaben für die technische und soziale Infrastruktur abschätzen zu können. Dieser Artikel fasst daher einerseits die Theorie fiskalischer Wirkungsanalysen zusammen und stellt anderseits Werkzeuge vor. Abschliessend werden Empfehlungen abgegeben zur Weiterentwicklung dieser Werkzeuge. Many local authorities lack the necessary knowledge and analytical tools to be able to estimate the effects that planned construction projects will have on tax revenues and on technical and social infrastructure expenditure. This article summarizes fiscal impact analysis theory as well as introducing relevant tools. Finally, it makes recommendations regarding ongoing development of these tools

Susceptibility of different life stages of Rhagoletis cerasi to entomopathogenic fungi

Die Kirschfruchtfliege Rhagoletis cerasi Loew (Diptera: Tephritidae) ist der wichtigste Schädling im Süßkirschenanbau in Europa. Bei unbehandelten Bäumen können bis zu 100% der Kirschen Madenbefall aufweisen. Da Handel und Verbraucher nur einen Befall von maximal 2% tolerieren, sind effiziente Bekämpfungsmaßnahmen gefragt. Der bisher verwendete Wirkstoff Dimethoate könnte im Zuge der Re-Evaluation von Pflanzenschutzmitteln in der EU seine Zulassung verlieren. Danach stünde die gesamte Kirschenproduktion in Europa vor der gleichen Situation wie derzeit der biologische Landbau: eine Regulierung der Kirschfruchtfliege wäre nur noch über Leimfallen oder durch den Einsatz von Netzen möglich. Beide Methoden sind sehr arbeitsintensiv und oft nicht ausreichend wirksam. Der Einsatz von Mikroorganismen als Biocontrol-Maßnahme könnte eine Alternative darstellen. Die Verwendung von entomopathogenen Pilzen zur Bekämpfung von Tephritiden wurde in den letzten Jahren von mehreren Autoren beschrieben (Anagnou-Veroniki et al., 2005; Ekesi et al., 2005; Konstantopoulou & Mazomenos, 2005; Yee & Lacey, 2005), wobei bisher noch keine Erfahrungen zu R. cerasi vorliegen. Ziel dieser Untersuchung war die Beurteilung verschiedener Pilzstämme (Deuteromycotina: Hyphomycetes) hinsichtlich ihrer Pathogenität und Virulenz gegen die Kirschfruchtfliege.The effects of six fungus strains (Deuteromycotina: Hyphomycetes) on the mortality of different life stages of the European cherry fruit fly, Rhagoletis cerasi Loew (Diptera: Tephritidae), were assessed in a series of laboratory experiments. All fungus strains caused mycoses in larvae and adults of R. cerasi. Virulence however varied considerably between the strains. Effects on L3-larvae were negligible; none of the fungus strains caused mortalities of more than 25% of larvae. Adults by contrast were highly susceptible to fungal infection. Beauveria bassiana and Paecilomyces fumosoroseus caused 90 to 100% mortality and had a strong influence on fecundity. Metarhizium anisopliae also showed reliable effects. The pathogenicity of Paecilomyces farinosus was low. Higher conidia concentrations lead to higher mortality, whereas B. bassiana was most efficient at low concentrations. Young flies showed lower mortality rates than older flies but, sub-lethal effects on eclosion rate of eggs were greater in young than in older flies

The ordering of green values: ecological justification in public fracking controversies in Germany and Poland

The article presents a comparative study of shale gas media debates in Germany and Poland. Drawing from the Sociology of Knowledge Approach to Discourse (SKAD), it addresses discursive conflicts over the use of hydraulic fracturing and its environmental impacts in both countries. The authors relate their analysis to the theoretical debate that emerged in the 1990s in French sociology concerning the question of “green justifications” that form a specific way of how social actors intervene, dispute, and build compromises in public discussions to protect non-human entities. Referring to these discussions, this article identifies several ecological justification clusters and the associated social actors that are ‘compromised’ or enclosed in existing orders of worth

Integrated economic-hydrologic water modeling at the basin scale: the Maipo river basin

Increasing competition for water across sectors increases the importance of the river basin as the appropriate unit of analysis to address the challenges facing water resources management; and modeling at this scale can provide essential information for policymakers in their resource allocation decisions. This paper introduces an integrated economic-hydrologic modeling framework that accounts for the interactions between water allocation, farmer input choice, agricultural productivity, nonagricultural water demand, and resource degradation in order to estimate the social and economic gains from improvement in the allocation and efficiency of water use. The model is applied to the Maipo River Basin in Chile. Economic benefits to water use are evaluated for different demand management instruments, including markets in tradable water rights, based on production and benefit functions with respect to water for the agricultural and urban-industrial sectors.Resource allocation., Water resources development Chile., Chile.,

Galápago leproso – Mauremys leprosa (Schweigger, 1812)

Reptiles - Orden Quelonios - Familia Geoemydidae en la Enciclopedia Virtual de Vertebrados Españoles, http://www.vertebradosibericos.org/.A comprehensive review of the natural history of the Mediterranean stripe-necked terrapin Mauremys leprosa in Spain.Peer reviewe

Selection criteria for flagship species by conservation organizations

Flagship species are among key marketing tools used by conservation organizations to motivate public support, but are often selected in an ad hoc, rather than systematic, manner. Furthermore, it is unclear whether selected flagship species do motivate public support. This paper describes a multi-method exploratory study, carried out in Switzerland, which aimed to determine the selection criteria for flagship species and measure whether a species selected according to these criteria was able to motivate support. Fourteen representatives of international, regional and local conservation organizations were interviewed and the selection criteria for their flagship species were identified. A charismatic species (the great spotted woodpecker) that meets these criteria and an apparently less charismatic species (the clover stem weevil) were selected as treatments in a quantitative experiment with 900 respondents. Using conjoint analysis, it was found that both charismatic and uncharismatic species have the ability to positively influence public preferences for habitat variables that encourage biodiversity in urban landscapes. These results may be used by conservation organizations to assist in the selection of flagship species, and in particular for flagship species that are intended to perform a specific conservation functio