Cherry leaf roll virus (CLRV) is a plant pathogen of economic and ecologic importance. It is globally distributed in a wide range of forest, fruit, and ornamental trees and shrubs. In several areas of cherry and walnut production CLRV causes severe losses in yield and quality. With current reference to the rapid dissemination and strong symptom expression in Finnish birches and the Germany-wide distribution of CLRV in birches and elderberry, we continuously investigate and gradually reveal CLRV transmission pathways as by pollen, seeds or water. However, modes and interactions responsible for the wide intergeneric host transmission as well as for the exceptional CLRV epidemic in Fennoscandia still remain unknown. In this project systematic studies shall investigate biological vectors as a causal agent to finally derive control mechanisms and strategies to avoid new epidemics in different hosts and geographic regions. Detailed monitoring of the invertebrate fauna of birch stands/forests and elderberry plantations in Germany and Finland shall reveal potential vectors to subsequently study them in detail by approved virus detection methods and transmission experiments. Molecular analyses of the CLRV coat protein shall prove its role as a viral determinant for a virus/vector interaction. Consequently, this project essentially will contribute important answers on the CLRV epidemiology, and this will be a key element within the first network of research on plant viral pathogens in forest trees.
Outbreaks of foodborne illness linked to consumptions of fresh, or partially processed, agricultural products are a growing concern in industrialized and developing countries. The incidence of human pathogens on fresh fruits and vegetables is often related to the use of recycled wastewaster in surface irrigation as well as high amounts of animal manure in agricultural management practice. Thereby the soil inhabiting fauna plays an important role in the transport and dissemination of microorganisms. The focus of the proposed project is on nematodes, well known vectors for bacteria and viruses in soil. The major goals are to: (1) survey human pathogens in soil and on/in free-living and plant parasitic nematodes in agriculture field sites irrigated with recycled wastewater or fertilized with fresh animal manure in Israel and the Palestinian Authority, (2) assess the function of nematodes as vectors in transmitting bacteria from microbial hot spots to plants, and (3) localize bacteria on and/or within the nematode and identify bacterial factors required for survival in the nematode host. Understanding the mechanisms involved in dissemination of human pathogens by nematodes will enhance the ability to develop practical means to minimize contamination of fresh produce and increase safety in food production.
Various species of pest insects cause substantial damage to agriculture every year, or transmit deadly diseases to animals and humans. A successful strategy to control pest insect populations is based on the Sterile Insect Technique (SIT), which uses the release of mass-reared, radiation sterilized male insects to cause infertile matings and thus reduce the pest population level. However, irradiation is not applicable to every insect species. Thus, new strategies based on genetic modifications of pest insects have been developed or are currently under investigation.The goal of the proposed research is to improve the development and ecological safety of genetically engineered (GE) insects created for enhanced biological control programs, including the SIT and new strategies based on conditional lethality. A major concern for GE insect release programs is transgene stability, and maintenance of their consistent expression. Transgene loss or intra-genomic movement could result in loss of strain attributes, and may ultimately lead to interspecies movement resulting in ecological risks. To address potential transgene instability, a new transposon vector that allows post-integration immobilization will be tested in the Mediterranean, Mexican and Oriental fruit fly tephritid pest species. In addition, the system will be established in the mosquito species Aedes and Anopheles - carriers of dengue and malaria.Random genomic insertion is also problematic for GE strain development due to genomic position effects that suppress transgene expression, and insertional mutations that negatively affect host fitness and viability. Diminished transgene expression could result in the unintended survival of conditional lethal individuals, or the inability to identify them. To target transgene vectors to defined genomic insertion sites having minimal negative effects on gene expression and host fitness, a recombinase-mediated cassette exchange (RMCE) strategy will be developed that. RMCE will also allow for stabilization of the target site, will be tested in tephritid and mosquito species, and will aid to the development of stabilized target-site strains for conditional lethal biocontrol. This will include a molecular and organismal evaluation of an RNAi-based lethality approach. Lethality based on an RNAi mechanism in the proposed insects would increase the species specificity and having multiple targets for lethality versus one target in existing systems. By seeking to improve transgene expressivity and stabilization of transposon-based vector systems, this proposal specifically addresses issues related to new GE insects by reducing their unintended spread after field release, and by limiting the possibilities for transgene introgression.
Ziel des Projekts ist die Entwicklung von speziellen Limiter-Techniken für Strömungs- und Transportprobleme. Im Mittelpunkt der geplanten Arbeiten stehen hochauflösende Finite-Elemente-Verfahren zur Simulation von Ozeanströmungen auf unstrukturierten Gittern. In erster Linie sollen die von den Antragstellern entwickelten und analysierten Ansätze an problemspezifische Anisotropien angepasst werden, die in geophysikalischen Anwendungen auftreten. Die neuen Limiter werden in der Lage sein, die horizontalen und vertikalen Komponenten separat zu beschränken, um eine übermäßige Verschmierung durch die numerische Diffusion zu verhindern. Darüber hinaus sollen die bisherigen Limiter-Konzepte auf Vektorfelder - insbesondere Geschwindigkeiten und diffuse Flüsse - erweitert werden. Um die Positivitätserhaltung im Rahmen eines vertikalen Wirbelviskositätsmodells zu garantieren, ist eine Sonderbehandlung für heterogene Diffusionskoeffizienten und nichtlineare Quellterme vorgesehen. Die anisotropen Flusskorrektur-Schemata und Ableitungslimiter sollen in die Software-Pakete UTBEST3D und FESOM integriert werden. Die erwartete Reduktion der unphysikalischen Vermischung soll durch detaillierte numerische Studien quantifiziert werden.
Mit der weltweiten Nutzung von Insektiziden stieg die Anzahl an resistenten Insekten-Arten bis 2006 auf etwa 550 Arten an. Selbst bei gezielter Anwendung von Insektiziden - zur Bekämpfung von Schädlingen in der Landwirtschaft zum Schutz der Ernten und zur Bekämpfung von Krankheitsüberträgern - kommen neben Zielorganismen auch Nicht-Zielorganismen in Kontakt mit den Wirkstoffen. Auf diese Weise entwickeln neben Zielorganismen, wie z.B. der Weißen Fliege, auch Nicht-Zielorganismen, wie z.B. die Taufliege Drosophila melanogaster, Resistenzen. Zu den weit verbreiteten Mechanismen, die Resistenzen bei Insekten auslösen, zählen sowohl die enzymatische Detoxifizierung als auch die Zielort-Unempfindlichkeit. Im ersten Fall begründet sich die Resistenz auf der Tatsache, dass das entsprechende Insekt über ein Enzym verfügt, das in der Lage ist, das betreffende Insektizid mit ausreichend hoher Geschwindigkeit zu Metaboliten umzusetzen, die eine geringere insektizide Wirkung aufweisen. Auf genetischer Ebene bedeutet das, (...) Das Projekt beschäftigt sich mit der P450-Monooxygenase CYP6G1 aus der Taufliege Drosophila melanogaster. Aus genetischen Studien ist bekannt, dass das Cyp6g1-Gen in resistenten Drosophila-Stämmen überexprimiert wird. Eine künstliche Überexpression von Cyp6g1 in Fliegen eines suszeptiblen Drosophila-Stamms führte zur Insektizid-Resistenz. Es wird vermutet, dass das CYP6G1-Enzym die Resistenz des Insekts bewirkt, indem bestimmte Insektizide, wie z.B. Imidacloprid und DDT, durch Metabolisierung detoxifiziert werden. Diese Hypothese soll im Projekt geprüft werden. P450-transgene Tabak-Zellsuspensionskulturen haben sich in unserer Arbeitsgruppe als geeignete in vivo-Systeme zur Untersuchung der Metabolismuskapazität von P450-Enzymen erwiesen. Der gleiche Ansatz wird beim CYP6G1 aus Drosophila melanogaster verfolgt. Im ersten Schritt werden Tabak-Zellsuspensionskulturen mit der cDNA-Sequenz des Cyp6g1 stabil transformiert. Mit den Cyp6g1-transgenen und den unmodifizierten Tabak-Kulturen werden nachfolgend Metabolismusexperimente durchgeführt, wobei z.B. Imidacloprid oder DDT (jeweils in 14C-markierter Form) eingesetzt werden. Durch Vergleich der nicht-transgenen mit der transgenen Tabak-Zellsuspensionskultur kann dann auf die Metabolismusaktivität des CYP6G1-Enzyms bezüglich des eingesetzten Insektizids geschlossen werden. Wichtige Metaboliten können identifiziert und isoliert werden. Der Nachweis, dass das heterolog exprimierte CYP6G1-Enzym das entsprechende Insektizid zu Verbindungen umsetzt, die keine insektizide Wirkung mehr zeigen, stellt dann das letzte Glied in der Beweiskette zur Ursache dieser Insektizid-Resistenz in Drosophila melanogaster dar. Die Prozedur ist analog auf andere Resistenz-Gene (Metabolismus-bedingt) anwendbar. Die resultierenden Erkenntnisse können im günstigen Fall genutzt werden, um (neue) Insektizide zu finden, die vom Resistenzmechanismus unberührt bleiben und deshalb der bestehenden Resistenz entgegenwirken.
Climate warming allows invasive pests to establish in areas where they have not been recognized before. Since its introduction in the 1950s in South France, Grapevine Fla-vescence dorée (GFD), a major disease of grapevines, has spread significantly in Europe and has now reached the southeast of Styria, which currently marks the northeastern border of its extension. The present project aims to model the current and future potential distribution of the disease and its vector, the leafhopper Scaphoideus titanus, in Europe under the influence of climate change. Vine growing areas of high risk in Austria will be defined. An epidemiological model will simulate the temporal and spatial dynamics of the spread of the disease and its vector. The epidemiological model will then be used to assess the potential economic impact of GFD to Austrian viticulture. The results of the project will be communicated to stakeholders, risk managers, policy makers and the public.
Cassava is a crop used by subsistence farmers in tropical and subtropical regions. It is extensively cultivated in certain regions of India and also in other Asian and African countries, and its cultivation is expected to further increase due to climate changes and increased water shortage, since cassava is drought-adaptive. Viruses, especially the begomoviruses Indian cassava mosaic-, Sri Lankan cassava mosaic- and African Cassava mosaic viruses (ICMV,SLCNV,ACMV here commonly I/SL/ACMV) cause dramatic losses in cassava cultivation. The plant recognizes viral RNA in the form of double-strand (ds)RNA, a by-product of virus replication. Long dsRNA is chopped by dicer enzymes into small interfering (si)RNAs, 21 to 24 base pair duplexes, consisting of a guide and a passenger-strand. The guide-strand forms together with the Slicer protein AGO a 'RISC'-complex which recognizes and cleaves cognate, i.e. in our case viral RNA. A remarkable feature of RNA interference (RNAi) is that, once started, it initiates a positive feedback loop, whereby the sliced RNA fragments are converted to more dsRNA by host RNA-dependent RNA polymerase, which give rise to more siRNAs. Furthermore, siRNAs or other components of the silencing pathway invade the plant systemically and protect from virus proliferation. Our antiviral strategy is to shift this equilibrium in favour of the plant by providing dsRNA cognate to the virus sequences. As a result, more siRNAs are produced, more virus RNA is destroyed and more systemic silencing signal reaches the growing tissue. Finally plants recover fast from initial infection or even become immune to incoming virus. Our project involves isolation, sequencing and cloning of the I/SL/ACV virus populations and their satellites occurring in the states of Andhra Pradesh, Maharashtra, Kerala, and Tamil Nadu. From these sequences a series of constructs will be derived that express hairpins, i.e. dsRNA with a loop between the RNA arms. We will construct variants that target all these viruses, including those that mimic natural micro (mi)RNAs or transacting (ta)siRNAs down-regulating host genes, and those provided with constitutive or virus-inducible promoters. We will optimize these constructs in transient assays to select those most efficient in initiating siRNA production. Selected constructs will then be cloned in Agrobacterium Ti-plasmid vectors and used for transformation of host plants. Although virus-resistant cassava is our goal, preliminary tests of the constructs could also be performed with the easily transformable Nicotiana benthamiana in one of our labs, as has been done by the applicants for African cassava mosaic begomovirus or with a more easily transformable model cassava cultivar with the help of Dr. Peng Zhang, Chinese academy of Science, Shanghai, thus extending a former collaboration of the Basel group with him.
This proposal is a continuation of the project 'GeoKernels': Kernel-Based Methods for Geo- and Environmental Sciences (200021-113944/1). The projects deal with the fundamental developments in the field of intelligent geospatial data analysis and modelling using Machine Learning algorithms. The first phase of the GeoKernels project provided a general methodology for using the state-of-the-art models in machine learning (where kernel methods establish one of the main successful areas) for spatio-temporal data analysis and modelling. Real life data lie on some lower-dimensional manifolds in the original high-dimensional geo-feature space. For environmental data these natural low-dimensional geo-manifolds are induced by rivers, relief features, urban structures, hydro-geological formations, etc. During PhaseI in the GeoKernels methodology, semi-supervised learning was applied to the stated problems in an efficient and elegant manner. The continuation of the project (Phase2) is aimed at advancing the data-driven GeoKernels modelling methodology, bringing it closer to the need of real-life operational use, from one side, and developing new methods concerned with geomanifold modelling by feature extraction and interpretable predictions with multiple kernel learning. The new developments will provide more transparency to the data-driven methods and will bring more flexibility for modelling complex environmental processes. The methods are particularly targeted at applications in natural hazards assessments and forecasting, topo-climatic modelling and renewable resources evaluation. Due to the established collaboration, the results of this multidisciplinary project will improve spatial data collection and management process in different scientific fields, will develop new procedures of environmental pattern recognition and modelling approaches using recent achievements in machine learning. The main results will be presented at the international conferences and workshops and published in scientific journals and books. The results, including the software modules (Machine Learning Office) and online interactive case studies will be available at the website of the project for the research and educational purposes (www.geokernels.org).
The aim of this research project is to study the metabolic fate of 13C-labelled nonylphenol in water, sediment and related microbial model systems. The main use of nonylphenol is the production of NP polyethoxilates. These nonionic surfactants have different application such as the production of industrial and household detergents. The most common route of nonylphenol to enter in the environment is through the wastewater. In fact NP polyethoxilates is most used in cleaners and for this reasons is discharged directly in the sewage system. Under anaerobic conditions NP polyetoxilates is degraded to NP. Laboratories studies on NP have demonstrated that NP can be classified as endocrine disrupter compound. Isomers highly branched in the alpha position of the nonyl chain show an higher estrogenic activity and that the para position is favorite as well for estrogenic activity.So far data on the metabolic fate of NP in water and soil are limitated in literature. Several studies have been performed in the laboratories about the metabolic fate of EDC using 14C labelled compounds. But this lead to 2 disadvantages: 1) the complete identification of the metabolites was not possible using GC/MS and 2) problems related with the discharge of radioactive compounds. For the previous reasons isomers of NP (353-NP, 363-NP, 33-NP) will be synthesised and labelled with 13C on the aromatic ring. An equimolar mixture of the labelled compound with the corresponding non labelled compound will yields a characteristic double peak with approximately the same abundance in MS analyses. Taking advantages of this it will be able to follow the degradation of nonylphenol in the experiments. The metabolic fate of NP exposed to different conditions will be studied: exposed to UV light, degraded by a recombinant yeast and in aerobic and anaerobic conditions. The first line of the project is to study the metabolic fate of NP exposed under condition of photo degradation. In fact NP can be exposed to sunlight when present in the aquatic environment. UV rays are of a short wavelength and have the energy to degrade products in sunlights. A lamp that had a ratio of UV-A and UV-B quite similar to the sun light was chosen. The NP degradation will be followed in a water/sediment system and in chlorinated water. The water sediment system and chlorinated water will be spiked with the nonylphenol, than the sample will be exposed to UV light at difference distance from the lamp and for different time. Than the metabolites will be extracted and analyzed via GC/MS. The second line of the project is to study the metabolic fate of NP after degradation with a recombinant yeast. The host used will be the yeast Saccharomyces cerevisiae, because it is well known and the genome of this yeast has been completely sequenced. The yeast will be transformed with an expression vector containing one cytochrome P-450 and the yeast reductase. Etc.
Nuklidvektoren wurden ermittelt, um die Messungen für die Freigabe nach § 29 der Strahlenschutzverordnung zu erleichtern. Dafür müssen die Nuklidvektoren aber repräsentativ und ausreichend konservativ sein. Im Vorhaben wurde die bisherige Praxis bei der Ermittlung von Nuklidvektoren dargestellt. Ausgehend von der Definition des Begriffs 'Repräsentativität' sind die möglichen Vorgehensweisen bei der Ermittlung repräsentativer Nuklidvektoren beschrieben. Die konkrete Gestaltung des Untersuchungsprogramms ist von der Zielstellung und der radiologischen Situation des zu untersuchenden Objekts abhängig. Für die einzelnen Schritte lassen sich aber verschiedene Möglichkeiten und Regeln für ein sachgerechtes Vorgehen beschreiben. Bei der Erstellung der Probenahmestrategie ist die Kompetenz des Bearbeiters der entscheidende Faktor für die Richtigkeit.
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