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Found 25 results.

Modes of vector transmission of Cherry leaf roll virus (CLRV) - molecular basis and potential arthropod vector species

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.

DFG Trilateral collaboration Deutschland-Israel-Palestine: Nematodes as potential vectors for human pathogens

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.

Emmy Noether-Nachwuchsgruppen, Development and risk assessment of transgenic environmentally-friendly insect pest control methods for fruit flies and mosquitoes

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.

Anisotrope Limiter-Techniken zur Simulation von Ozeanströmungen auf unstrukturierten Gittern

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.

Austrian Climate Research Programme (ACRP), KPC - Modelling epidemiological and economic consequences of Grapevine Flavescence doree phytoplasma to Austrian viticulture under a climate change scenario

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.

Integrated control of thrips in vegetables in Eastern Africa - development of user-friendly ID tools

Main goals: 1. Identity, importance and distribution of major plant infesting thrips studied in Kenya and Uganda. 2. Conduct surveys for thrips, natural enemies and TSWV in cultivated plants and surrounding vegetation in Eastern Africa. 3. Development of a thrips identification key using LucID 3.4 software. 4. Fact sheet fusion database with special reference to tospovirus vectors. 5. Finally production of a CDROM: Pest thrips of Africa. (in collaboration with ICIPE/Nairobi)

Effectiveness of surveillance, prevention and control strategies of avian influenza

The spread of highly pathogenic avian influenza (HPAI) is a global threat to all countries with a poultry industry, semi-commercial production and backyard poultry and has already caused enormous economic losses. Since 1997, H5N1 viruses which have infected humans have included Haemagglutinins from several clades and variable genotypes. Therefore, all HPAI H5N1 viruses must be considered a potential threat to public health. This increases the scope of viruses with pandemic potential and the importance of continued surveillance of H5N1 avian influenza outbreaks. WHO and the OIE are urging countries worldwide to initiate surveillance programmes tailored to an early detection of cases of HPAI. There is an international demand to reduce random sampling and redirect the scarce resources to a targeted sampling, which focuses on the high-risk population, which is even more true for developing countries e.g. in Africa, which are almost devoid of surveillance capacity. In these cases, risk-based surveillance, and aiming at the most probable source of disease to save scarce resources are even more justified. This project aims: 1) To develop a statistical risk based framework for the combined analysis of surveillance data on avian influenza virus originating from various sources. 2) To develop a model for the assessment and optimisation of the effectiveness of different surveillance strategies for avian influenza. 3) To develop models to assess the effectiveness of different control strategies to prevent infection and spread of HPAI in commercial poultry. The approach is based on the Swiss Tropical Institute's competence in Bayesian spatial risk analyses, transmission modelling of vector borne and zoonotic diseases and its international network in Africa and Asia. This project will focus on Switzerland but within the global context of transport, trade and wild bird migration. It will collaborate with all involved institutions in Switzerland dealing with domestic poultry and wild birds. Expected results and innovations are: 1. Risk maps and contributions to risk maps for LPAI and HPAI on wild and domestic birds in Switzerland. 2. Decision tree for AI risk based surveillance in Switzerland applicable also to low income countries. 3. Risk based surveillance map and sampling plan for AI in Switzerland. 4. Performance indicators of surveillance sensitivity and cost-effectiveness of surveillance of AI in Switzerland and 5. A transmission model of HPAI adapted to Switzerland capable to simulate different intervention strategies.

FP6-SUSTDEV, Emerging Diseases in a Changing European Environment (EDEN)

Erzeugung transgener Gehölze und Sicherheitsforschung unter besonderer Berücksichtigung der Endophytenproblematik - Literaturstudie

Ziel des Projektes ist die Erstellung einer Literaturübersicht zum Stand der Entwicklung transgener Gehölze und zu den Möglichkeiten (Risikopotential) eines horizontalen Gentransfers in Forstgehölzen. Bei der Erzeugung transgener Gehölze werden binäre Vektoren verwendet, die aus den natürlichen Ti-Plasmiden von Agrobakterien entwickelt wurden. Mit Hilfe dieser Vektorsysteme wird die zu übertragende rekombinante DNA in die Pflanzenzellen eingeschleust. Daneben kann die DNA über bakteriellen Gentransfer auch in andere Bakterien übertragen werden. Durch das Vorhandensein endophytischer Bakterien in Bäumen und die relativ lange Persistenz der Agrobakterien in transformierten Gehölzen besteht somit ein Risiko des horizontalen Gentransfers, das bisher kaum beschrieben wurde. In der Studie wird der Kenntnisstand zum Vorkommen von Endophyten in Forstgehölzen, zur Persistenz von Agrobakterien sowie zu den Mechanismen des bakteriellen Gentransfers dokumentiert. In Verbindung mit den Eigenschaften der verwendeten Vektoren werden hieraus prinzipielle Möglichkeiten für den Gentransfer in die Endophytenflora beschrieben und Schlussfolgerungen für den Forschungsbedarf abgeleitet.

Depletion of algal toxin-contaminated water using selective biofilters based on plant-produced antibodies (plantibodies)

Although the use of genetically modified plants for bioremediation, or the in situ cleaning of contaminated sites, has been known for quite some time, little attention has so far been paid to the production of antibodies in plants and their ex vivo application in selective depletion. Therefore, highly affine and specific antibodies against algal toxins using microcystin as an example will be produced in plants at low cost within this research project. The basis is a monoclonal antibody (Mab 10E7, species: mouse) generated in a former research project. The sequence of the variable domains will be determined, optimized for plants and sub cloned into suitable plant transformation vectors, which already contain constant antibody sequences. In addition, a scFv fragment containing different tag sequences and fusion proteins will be constructed. Leaf-based (tobacco) as well as seed-based (barley) systems will be used.Affinity-purified plant-produced antibodies (plantibodies) will be characterized in detail for their binding properties using microtitre plate-ELISA and surface plasmon resonance (SPR). The monoclonal mouse antibody will be used as reference. To assure cost-efficiency for future applications, roughly purified fractions (sequential pH and temperature treatment followed by filtration) will be tested for the upscaling. Following immobilization of the plantibody fractions on suitable substrates, for instance membranes, porous polymer monoliths or in porous glasses, their application for depletion will be defined using model water samples spiked fortified with microcystins.

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