Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Review of insect pathogen risks for the black soldier fly (Hermetia illucens) and guidelines for reliable production
    Joosten, Lotte ; Lecocq, Antoine ; Jensen, Annette Bruun ; Haenen, Olga ; Schmitt, Eric ; Eilenberg, Jørgen - \ 2020
    Entomologia Experimentalis et Applicata 168 (2020)6-7. - ISSN 0013-8703 - p. 432 - 447.
    bacteria - biocontrol agents - black soldier fly - Diptera - entomopathogens - epidemiology - feed and food - fungi - guidelines - Hermetia illuscens - immune system - protozoa - Stratiomyidae - viruses

    Black soldier fly [BSF; Hermetia illucens L. (Diptera: Stratiomyidae)] larvae are very effective in transforming low-grade food waste into valuable high-end proteins and fat, in intensive production facilities. The production output of this species is growing quickly, but upscaling brings risks to the health status of the reared insects. Until now, not a single major case of disease outbreak caused by a pathogen in a BSF production unit has been reported. This contrasts with data on other species of mass-produced insects, which have experienced various disease outbreaks, indicating that BSFs are comparatively resistant to insect diseases. Further, there are no records of natural infections caused by entomopathogens in BSF. In this review, the known entomopathogens of Diptera, especially BSF, and their potential risks for causing disease in these insects are summarized.

    Dataset for: Presence of seed-borne pest and pathogens on/in the seed produced by farmers in the province of Cotopaxi
    Navarrete Cueva, Israel ; Andrade, Jorge ; Almekinders, Conny ; Struik, Paul - \ 2019
    Kansas State University
    seed degeneration - nematodes - fungi - viruses - seed tubers - seed damaging insects - Potato - Rhizoctonia - Streptomyces scabies - Fusarium - Silver scurf - Powdery scabs - Andean potato weevil - Potato tuber moth - White grub - Wireworm - Flea beetle - PVS - PVY - PVX - PLRV - APMoV - Globodera pallida - Tylenchus spp. - Pratylenchus spp. - Aphelenchoides spp. - Heterodera spp. - Meloidogyne spp. - Paratylenchus Spp. - Saprophytes - Tylenchorhynchus spp.
    Seed degeneration (PSD) threats potato production in developing countries. PSD is defined as the accumulation of pest and pathogens in/on the seed tuber due to the successive cycles of vegetative propagation leading potentially to a yield and quality reduction (Thomas-Sharma et al., 2016; Pl. Path. [vol 65, issue 1]). However, the understanding of PSD in the Andes is deficient due to the limited comprehension of the spatial distribution of potato seed- and soil- borne pests and pathogens. For this reason, 260 farmers´ seed lots and fields were surveyed in the province of Cotopaxi-Ecuador from September to October 2018. The survey was implemented using a stratified sampling design (stratum = Cantons of Latacunga, Pujilí, Salcedo and Saquisilí). The sample size was defined based on the seed replacement rate reported by farmers in a pilot study previously implemented. In each place, farmers kindly provided a sample of (1 to 10) potato seed tubers depending on their willingness. In addition to it, a soil sample was collected from the closest field to the house after farmers provided oral consent. Symptoms and damages on the seed tubers caused by insects and fungi were visually inspected following the methodology suggested by James (1971, [Canadian pl. dis. survey {vol. 51}]) and the photography guide of the main pests and pathogens of the potato crop in Ecuador (Montesdeoca et al., 2013)(Reported in sheet coined "Insects and Fungi"). Virus identification was carried out on plantlets coming from the tubers assessed previously. This was performed by using the kits and the protocol for DAS-ELISA manufactured and suggested by CIP (2007). Six viruses were identified: PVX, PVS, PVY, APLV, PLRV, and APMoV (Reported in sheet coined "Virus"). Forty three soil samples out of the 260 were selected depending on the farmers’ field altitude and landscape location (Reported in sheet coined "nematodes"). These were sent to the laboratory of Plant Protection of the National Agriculture Research Center (INIAP) for nematodes identification. Nematodes were identified according to the methodologies of Oostenbrink (1960) and Fenwick (1940). It is expected that this database contributes to a deeper knowledge about the presence of seed-borne pests and pathogens in the tropical highlands of Ecuador and to design better seed system interventions.;The dataset contains data about presence of seed-borne pest and pathogens on/in the seed produced by farmers in the province of Cotopaxi.
    Zaadoverdracht van het Strawberry latent ringspot virus in lelie : eindrapportage onderdeel zaadoverdracht van het onderzoek naar verspreidingsroutes van SLRSV in lelie
    Verbeek, Martin ; Stijger, Ineke ; Lemmers, Miriam - \ 2016
    Lisse : Praktijkonderzoek Plant & Omgeving, onderdeel van Wageningen UR, Business Unit Bloembollen, Boomkwekerij en Fruit - 21
    lelies - lilium - latent aardbeikringvlekkenvirus - virussen - quarantaine organismen - xiphinema - xiphinema diversicaudatum - overdracht - zaden - lilies - lilium - strawberry latent ringspot virus - viruses - quarantine organisms - xiphinema - xiphinema diversicaudatum - transfer - seeds
    Het Strawberry latent ringspot virus (SLRSV, in het Nederlands Latent aardbeikringvlekkenvirus) komt in een groot aantal gewassen voor, waaronder o.a. aardbei, framboos, bessenstruiken, verschillende fruitbomen (kers, pruim, perzik), groenten en kruiden (asperge, selderij, peterselie) en siergewassen (roos, lelie en narcis). Binnen de EU is dit virus een quarantaine organisme in plantmateriaal van aardbei, braam en framboos. In andere delen van de wereld is SLRSV ook een quarantaine organisme in andere gewassen, voor de export van lelie naar o.a. China en de Verenigde Staten geldt een 0-tolerantie. SLRSV wordt overgebracht door een tweetal aaltjes-soorten: Xiphinema diversicaudatum en X. coxi. Er zijn echter vermoedens dat dit virus ook op andere manieren verspreid kan worden dan alleen door de twee genoemde Xiphinema-soorten. Er is namelijk overdracht waargenomen in teelten waarin geen Xiphinema is waargenomen. De vraag is dus op welke manieren SLRSV kan worden verspreid. In de literatuur is al gerapporteerd dat SLRSV in een hoog percentage (~70%) met zaad over kan gaan in bijvoorbeeld selderij, munt en braam. Van zaadoverdracht in het gewas lelie is tot op heden nog niets bekend. Bovendien kan het virus zeer algemeen voorkomende onkruiden als herderstasje en muur infecteren. Het doel van het onderzoek waarover in dit verslag wordt gerapporteerd was het nagaan of de verspreiding van SLRSV in lelie al dan niet via zaadoverdracht kan plaatsvinden. Hiervoor werden experimenten uitgevoerd met een vijftal leliecultivars die via zaad worden vermeerderd. SLRSV kon bij deze cultivars in het zaad, het stuifmeel en in nieuwe zaailingen worden aangetoond. SLRSV kon zo in hoge mate worden aangetoond in zaden afkomstig uit partijen met een zeker percentage SLRSV. Bij één cultivar werd een percentage van 30% infectie gevonden in zaailingen die waren gegroeid uit zaad uit een besmette partij. Het virus kon ook worden aangetoond in het stuifmeel van geïnfecteerde bloemen. De vraag of het virus ook via stuifmeel kan worden overgedragen van de ene plant naar de andere plant wordt op moment van deze rapportage nog onderzocht in een project gefinancierd door iBulb. Sommige zaad-overgedragen virussen verblijven voornamelijk aan de buitenkant van het zaad (op of in de zaadhuid) en infecteren het nageslacht pas wanneer de kiemplant door de zaadhuid heen breekt (bijvoorbeeld potexvirussen en tobamovirussen). Bij dit soort virussen is een zaadontsmetting nog een mogelijkheid om infectie van de jonge kiemplantjes te voorkomen. In het onderzoek waarover hier wordt gerapporteerd is naar voren gekomen dat SLRSV tot een andere categorie virussen behoort, namelijk de virussen die zaadoverdraagbaar zijn en daarbij al in het zaad in endosperm en zelfs het embryo aanwezig zijn. Voor deze groep virussen is zaadontsmetting geen remedie tegen zaadoverdracht. Samengevat heeft dit onderzoek de volgende nieuwe inzichten opgeleverd: • SLRSV is zaadoverdraagbaar in lelie • SLRSV is aantoonbaar in endosperm en embryo van leliezaad. Zaadontsmetting is geen optie om zaadoverdracht te voorkomen.
    Microbes and asthma : Opportunities for intervention
    Smits, Hermelijn H. ; Hiemstra, Pieter S. ; Prazeres Da Costa, Clarissa ; Ege, Markus ; Edwards, Michael ; Garn, Holger ; Howarth, Peter H. ; Jartti, Tuomas ; Jong, Esther C. De; Maizels, Rick M. ; Marsland, Ben J. ; McSorley, Henry J. ; Müller, Anne ; Pfefferle, Petra I. ; Savelkoul, Huub ; Schwarze, Jürgen ; Unger, Wendy W.J. ; Mutius, Erika Von; Yazdanbakhsh, Maria ; Taube, Christian - \ 2016
    Journal of Allergy and Clinical Immunology 137 (2016)3. - ISSN 0091-6749 - p. 690 - 697.
    asthma - helminths - Hygiene hypothesis - immune regulation - microbes - microbiome - sensitization - viruses

    The worldwide incidence and prevalence of asthma continues to increase. Asthma is now understood as an umbrella term for different phenotypes or endotypes, which arise through different pathophysiologic pathways. Understanding the many factors contributing to development of the disease is important for the identification of novel therapeutic targets for the treatment of certain asthma phenotypes. The hygiene hypothesis has been formulated to explain the increasing prevalence of allergic disease, including asthma. This hypothesis postulates that decreased exposure at a young age to certain infectious agents as a result of improved hygiene, increased antibiotic use and vaccination, and changes in lifestyle and dietary habits is associated with changes in the immune system, which predispose subjects to allergy. Many microbes, during their coevolution with human subjects, developed mechanisms to manipulate the human immune system and to increase their chances of survival. Improving models of asthma, as well as choosing adequate end points in clinical trials, will lead to a more complete understanding of the underlying mechanisms, thus providing an opportunity to devise primary and secondary interventions at the same time as identifying new molecular targets for treatment. This article reports the discussion and conclusion of a workshop under the auspices of the Netherlands Lung Foundation to extend our understanding of how modulation of the immune system by bacterial, parasitic, and viral infections might affect the development of asthma and to map out future lines of investigation.

    Weerbaarheid, ook tegen plantenvirussen!
    Stijger, C.C.M.M. ; Verbeek, M. - \ 2015
    Wageningen UR
    gewasbescherming - tuinbouw - plagenbestrijding - virussen - bodemweerbaarheid - verbetering - conferenties - biologische bestrijding - plant protection - horticulture - pest control - viruses - soil suppressiveness - improvement - conferences - biological control
    Minder virus (schade) in een economisch rendabele en duurzame teelt door: 1. Afbraak virusdeeltjes door bacteriën/schimmels. 2. Vatbaar wordt onvatbaar door genetische aanpassing van de plant. 3. Symptoomonderdrukking. Poster van PlantgezondheidEvent 12 maart 2015.
    Antibody response and risk factors for seropositvity in backyard poultry following mass vaccination against highly pathogenic avian influenza and Newcastle disease in Indonesia
    McLaws, M. ; Priyono, W. ; Bett, B. ; Al-Qamar, S. ; Claassen, I.J.T.M. ; Widiastuti, T. ; Poole, J. ; Schoonman, L. ; Jost, C. ; Mariner, J. - \ 2015
    Epidemiology and Infection 143 (2015)8. - ISSN 0950-2688 - p. 1632 - 1642.
    domestic poultry - h5n1 - ducks - surveillance - countries - efficacy - vaccines - vietnam - viruses - field
    A large-scale mass vaccination campaign was carried out in Java, Indonesia in an attempt to control outbreaks of highly pathogenic avian influenza (HPAI) in backyard flocks and commercial smallholder poultry. Sero-monitoring was conducted in mass vaccination and control areas to assess the proportion of the target population with antibodies against HPAI and Newcastle disease (ND). There were four rounds of vaccination, and samples were collected after each round resulting in a total of 27 293 samples. Sampling was performed irrespective of vaccination status. In the mass vaccination areas, 20–45% of poultry sampled had a positive titre to H5 after each round of vaccination, compared to 2–3% in the control group. In the HPAI + ND vaccination group, 12–25% of the population had positive ND titres, compared to 5–13% in the areas without ND vaccination. The level of seropositivity varied by district, age of the bird, and species (ducks vs. chickens).
    Virus : buitenland kijkt al lang mee
    Dwarswaard, A. ; Kock, M. de - \ 2014
    BloembollenVisie 2014 (2014)313. - ISSN 1571-5558 - p. 75 - 75.
    bloembollen - landbouwkundig onderzoek - effecten - virussen - plantenziekteverwekkers - gewasbescherming - plantenveredeling - resistentie van variëteiten - ornamental bulbs - agricultural research - effects - viruses - plant pathogens - plant protection - plant breeding - varietal resistance
    De afgelopen eeuw is er veel onderzoek gedaan aan bloembollen. Praktische problemen werden opgelost. Nu de sector op een keerpunt staat waar het gaat om de collectieve financiering van onderzoek, is het goed om nog eens na te gaan wat het onderzoek de praktijk heeft gebracht. in deze serie staat die vraag centraal. Dit keer: onderzoek aan virussen.
    Bronnen van Aardappelvirus Y
    Vlugt, R.A.A. van der; Bekkum, P.J. van; Raaij, H.M.G. van; Piron, P.G.M. ; Verbeek, M. ; Topper, C.G. ; Bus, C.B. ; Wustman, R. - \ 2014
    Wageningen : Kennisakker
    akkerbouw - aardappelen - proeven op proefstations - gewasbescherming - virussen - aardappelvirus y - ziekten overgebracht door vectoren - onkruiden - besmetters - arable farming - potatoes - station tests - plant protection - viruses - potato virus y - vector-borne diseases - weeds - contaminants
    Gedurende het groeiseizoen 2011, tussen begin april en eind augustus, heeft Plant Research International, samen met PPO-AGV, onderzoek uitgevoerd naar de mogelijke bronnen van besmettingen met het aardappelvirus Y (PVY) in aardappelen. Er is vooral gekeken naar de rol van bladluizen als belangrijkste overbrengers (‘vectoren’) van PVY en naar mogelijke bronnen van het virus in andere planten (met name onkruiden).
    Protein-based polymers that bond to DNA : design of virus-like particles and supramolecular nanostructures
    Hernandez Garcia, A. - \ 2014
    Wageningen University. Promotor(en): Martien Cohen Stuart, co-promotor(en): Renko de Vries; P. Schoot. - Wageningen : Wageningen University - ISBN 9789461738233 - 242
    polymeren - polymeerchemie - eiwitten - dna - dna-bindende eiwitten - virussen - nanotechnologie - virusreplicatie - virusachtige deeltjes - polymers - polymer chemistry - proteins - dna - dna binding proteins - viruses - nanotechnology - viral replication - virus-like particles

    In this thesis it is demonstrated that it is possible to use Protein-based Polymers (PbPs) as synthetic binders of DNA (or any other negatively charged polyelectrolyte). The PbPs co-assemble with their DNA templates to form highly organized virus-like particles and supramolecular structures. A range of PbPs have been developed over the last decades that can be used as precision functional polymers, and which integrate the unique properties of both proteins and polymers. Many PbPs are based on nature-inspired simple repetitive amino acid sequences. In this thesis, different kinds of such sequences have been combined into PbPs that mimic complex natural functionalities. Being intermediate between proteins and polymers, it has been able to mimic complex functionalities typically found for folded proteins, while retaining the tunability and ease of control that is more characteristic for (synthetic) polymers. Indeed, using clear design rules, biosynthetic PbPs sequences have been obtained and produced that co-assemble with nucleic acids to form true artificial viruses, which mimic their natural counterparts in many respects.

    The motivation for developing artificial viruses derives among others from the growing interest in exploiting natural self-assembled virus structures to develop nanostructured materials. In addition, natural viruses are being used as scaffolds for delivering DNA in the context of gene therapy, to serve as vaccines (by displaying antigens), to template diverse materials, to produce energy, to catch light, to catalyze reactions, to serve as contrasting agents, etc. Developing artificial viruses would serve not only to advance our capabilities to understand and control the co-assembly of nanostructures, but would also generate useful synthetic biomaterials that are even more suited than natural viruses to be used as building blocks for nanostructured materials. In short, the successful development of artificial viruses may be expected to give rise not only to new insights on templated self-assembly, but will also be very important for a range of applications.

    The main part of the thesis is divided into three parts. In part I, “Complexation of DNA into virus-like particles”, we describe details of the molecular biomimetic strategy to design and produce PbPs with functionalities that mimic those of natural viruses. Part II, “Applications of protein-DNA complexes”, deals with the development of diblock PbP that coat DNA, and with their applications in gene delivery and optical mapping of long DNA. Finally, in part III: “Supramolecular nanostructures beyond DNA” we consider the co-assembly of our PbPs with templates other than DNA, and also consider their self-assembly in the absence of DNA.

    Statistical guidelines for Apis mellifera research
    Pirk, C.W.W. ; Miranda, J.R. ; Kramer, M. ; Murray, T.E. ; Nazzi, F. ; Shutler, D. ; Steen, J.J.M. van der; Dooremalen, C. van - \ 2013
    Journal of Apicultural Research 52 (2013)4. - ISSN 0021-8839
    division-of-labor - honey-bees - sample-size - nosema-apis - prevalence - viruses - models - larvae - power
    In this article we provide guidelines on statistical design and analysis of data for all kinds of honey bee research. Guidelines and selection of different methods presented are, at least partly, based on experience. This article can be used: to identify the most suitable analysis for the type of data collected; to optimise one's experimental design based on the experimental factors to be investigated, samples to be analysed, and the type of data produced; to determine how, where, and when to sample bees from colonies; or just to inspire. Also included are guidelines on presentation and reporting of data, as well as where to find help and which types of software could be useful.
    Geografische patronen in sterfte / geen sterfte
    Scheer, H. van der; Blacquière, T. - \ 2013
    Bijenhouden 6 (2013)september. - ISSN 1877-9786 - p. 19 - 22.
    apidae - honingbijen - wilde bijenvolken - rassen (dieren) - doodsoorzaken - wereld - varroa - insecticiden - virussen - varroa jacobsoni - resistentie van variëteiten - dierziekten - apidae - honey bees - wild honey bee colonies - breeds - causes of death - world - varroa - insecticides - viruses - varroa jacobsoni - varietal resistance - animal diseases
    Sinds 2006 worden uit Europa en Noord-Amerika op grote schaal ernstige verliezen van honingbijvolken gemeld; maar niet uit andere werelddelen. Er ijn verschillende oorzaken aan te wijzen. Neonicotinen worden aangewezen als (mede) oorzaak van de verliezen, maar waarom worden die verliezen dan vooral uit Europa en Noord-Amerika en slechts incidenteel uit het Midden-Oosten en Azië (Japan) gemeld? De gewraakte insecticiden worden wereldwijd toegepast. Om verschillende redenen moet er eerder aan problemen door varroamijten en virussen worden gedacht.
    Archaeal virus-host interactions
    Quax, T.E.F. - \ 2013
    Wageningen University. Promotor(en): John van der Oost, co-promotor(en): D. Prangsihvili. - Wageningen : Wageningen UR - ISBN 9789461737830 - 186
    virussen - sulfolobus islandicus rod-shaped virus 2 - archaea - virus-gastheer interacties - infecties - viruses - sulfolobus islandicus rod-shaped virus 2 - archaea - virus-host interactions - infections

    The work presented in this thesis provides novel insights in several aspects of the molecular

    biology of archaea, bacteria and their viruses.

    Three fundamentally different groups of viruses are associated with the three domains of life.

    Archaeal viruses are characterized by a particularly high morphological and genetic diversity. Some

    archaeal viruses, such as Sulfolobus islandicus rod-shaped virus 2 (SIRV2), have quite remarkable

    infection cycles. As described in Chapter 1, infection with SIRV2 results in the formation of

    large virus associated pyramids (VAPs) on the host cell surface. The structures open in the final

    step of the infection cycle, creating large apertures to release the rod-shaped viruses that have

    matured in the cytoplasm. This virus release mechanism is unique and does not resemble egress

    mechanisms of bacterial and eukaryotic viruses. Analysis of the protein composition of SIRV2

    infected cells, as outlined in Chapter 2, revealed the strong accumulation of the virus encoded

    protein PVAP in membranes after infection, suggesting involvement in VAP formation. The

    VAPs can be isolated as discrete particles, as demonstrated in Chapter 3. Electron microscopic

    survey of these particles showed that they are baseless pyramids with a heptagonal perimeter.

    This geometry is exceptional and especially the sevenfold symmetry is very rare in nature

    (20S proteasome, myosin). The structures can have various sizes, probably reflecting different

    developmental stages. This suggests that they grow by the gradual expansion of the triangular

    facets. Analysis of the protein composition of the structures revealed the exclusive presence of

    PVAP and anti-bodies raised against this protein labeled specifically the VAPs on thin sections

    of infected cells as observed in electron microscopy. PVAP is sufficient for VAP formation, which

    was demonstrated by expression of the protein and successful assembly of pyramidal structures,

    in the archaeon S. acidocaldarius and the bacteria Escherichia coli. Further analysis of PVAP

    truncation mutants as outlined in Chapter 4, showed that besides the 10 C-terminal amino

    acids, all domains of the protein are essential for VAP formation. PVAP can form oligomers of

    several sizes, including those of a heptamer, which probably act as nucleation points for VAP

    formation on the cell membrane. Analysis of the truncation mutants indicated that both the C

    and N terminal domain are important for interaction between monomers. Detailed observation

    with whole cell cryo-electron tomography of VAPs formed in the natural and heterologous

    system, revealed the presence of two layers in the structure. The outer one is continuous with

    the cell membrane. The inner layer facing the cytoplasm, presumably represents a protein sheet

    formed by tight interactions between the C-terminal domain of PVAP connected with a short

    linker region to the membrane. The sheets are slightly bended, giving the complete structure the

    appearance of a teepee. At the junction of two triangular sheets, the structure is perforated,

    creating predetermined breaking points. Furthermore, in this chapter data is presented which

    underlines the unique nature of this protein, since it is able to form VAPs successfully in

    archaeal, bacterial and eukaryotic membranes, which all fundamentally differ in protein and

    lipid composition. In case of expression in Saccharomyces cerevisiae, VAPs are formed on all

    membranes, including those of mitochondria, suggesting that the protein inserts spontaneously

    in membranes. Thus, PVAP serves as a universal membrane remodeling system, which might be

    exploited for biotechnological purposes, such as the development into a universal system for the

    controlled opening of ~100 nm apertures in any lipid bilayer.

    Production of VAPs is one of the dramatic consequences that SIRV2 infection has on the

    host cell. Whole transcriptome sequencing allowed determination of a global map of virus

    and host gene expression during the infection cycle, which is presented in Chapter 5. Directly

    after infection, transcription of viral genes starts simultaneously from both genome termini. All

    possible protein interactions between all SIRV2 proteins were assayed with yeast two-hybrid

    and these results were used to advance current knowledge on SIRV2 genes functions, of which

    the majority is still unidentified. The host cells respond to viral infection by adapting expression

    of more than 30% of its genes. Genes involved in cell division are down regulated, while those

    playing a role in anti-viral defense are activated. Specifically, for the first time massive activation

    of toxin anti-toxin and CRISPR-Cas systems is observed in an archaeal system. The different

    degree of expression and activation of the various systems highlights the specialized functions

    they perform.

    The CRISPR-associated multi-subunit ribonucleoprotein complexes that are crucial for the

    CRISPR mediated anti-viral defense, generally have an uneven stoichiometry, i.e. the 4-6 different

    protein subunits are present in different quantities. Just as most functionally related bacterial and

    archaeal genes, the cas genes are clustered in operons, which allow for co-expression (as has

    indeed been observed in the transcriptome analysis described in Chapter 5). This is advantageous

    when equal amounts of gene products are required, such as is the case for protein complexes

    with even stoichiometry. However, a substantial number of important protein complexes

    contain uneven stoichiometry. Employing comparative genomics, in Chapter 6, it is shown

    that differential translation is a key determinant of modulated expression of genes clustered

    in operons and that codon bias generally is the best in silico indicator of unequal protein

    production. In addition, analysis of protein production from genes with synonymous mutations

    from synthetic operons, provides evidence that initiation of translation can occur at intercistronic

    sites. The widespread occurrence of modulation of translation efficiency, suggests that this is

    a universal mode of control in bacteria and archaea that allows for differential production of

    operon-encoded proteins.

    Juiste moment bladbemonstering cruciaal voor nauwkeurige toetsuitslag
    Kock, M.J.D. de - \ 2013
    BloembollenVisie 2013 (2013)274. - ISSN 1571-5558 - p. 24 - 25.
    lelies - bloembollen - virussen - timing - bemonsteren - methodologie - elisa - lilies - ornamental bulbs - viruses - timing - sampling - methodology - elisa
    Sinds dit jaar worden bladmonsters van lelie bij de BKD met de Elisa-methode standaard op vier virussen getoetst. Het is belangrijk om een nauwkeurige toetsuitslag te krijgen, omdat dit resultaat wordt gebruikt voor partijbeheer, teeltplanning, bepalen van de gewasbeschermingsstrategie, handel en export. Dit artikel geeft aan de hand van de verspreidingsroutes van de vier virussen en de invloed van het virus op de plant het meest geschikte moment van bemonsteren. Daarnaast beantwoordt de BKD een aantal veel gestelde ragen over dit onderwerp.
    Introductietraject sleedoornonderstammen
    Steeg, P.A.H. van der; Maas, F.M. ; Ravesloot, M.B.M. - \ 2013
    Randwijk : Praktijkonderzoek Plant en Omgeving, Bloembollen, Boomkwekerij & Fruit - 19
    prunus spinosa - onderstammen - vermeerderingsmateriaal - fruitgewassen - rassen (planten) - selectie - veredelingsmethoden - virussen - gebruikswaarde - kwekersrecht - wettelijke rechten - plantenvirussen - nederland - prunus spinosa - rootstocks - propagation materials - fruit crops - varieties - selection - breeding methods - viruses - use value - breeders' rights - legal rights - plant viruses - netherlands
    Uit het onderzoek naar de gebruikswaarde van sleedoornselecties als onderstam voor pruim zijn sele cties naar voren gekomen die zeer perspectiefvol zijn . Deze hebben een groeikracht tussen die van VVA - 1 en St. Julien A (Van der Steeg et al, 2011 ). PPO is eigenaar van deze selecties. Vanuit de steenfruitsector bestaat hiervoor veel belangstelling . Men wil graag zo snel mogelijk bomen op deze onderstammen kunnen planten. Voordat éé n of meer selecties in de praktijk geïntroduceerd zouden kunnen worden, dien d en ze echter: - virusvrij gemaakt te worden - wettelijk beschermd te worden - vermeerderd te worde n Daarnaast wa s er de behoefte om ‘pilot s ’ op te zetten om de waarde aan de sector te demonstreren. Verder diende ook in het buitenland interesse ge wek t te worden voor het gebruik van deze selecties als onderstam voor pruim, kwets en mogelijk ook voor abri koos, perzik en nectarine. Dit is een grote potentiële afzetmarkt voor de onderstammen, waarmee de collectieve investering geld kan opleveren. In 2011 en 2012 is in een viertal projecten aan deze zaken invulling gegeven. In dit rapport worden de projecten beschreven.
    Bat Rabies Surveillance in Europe
    Schatz, J. ; Fooks, A.R. ; McElhinney, L.M. ; Horton, D. ; Echevarria, J. ; Vázquez-Morón, S. ; Kooi, E.A. ; Rasmussen, T.B. ; Müller, T. ; Freuling, C. - \ 2013
    Zoonoses and Public Health 60 (2013)1. - ISSN 1863-1959 - p. 22 - 34.
    lyssavirus type-1 - serotine bats - phylogenetic-relationships - experimental-infection - eptesicus-serotinus - germany - origin - eblv-2 - populations - viruses
    Rabies is the oldest known zoonotic disease and was also the first recognized bat associated infection in humans. To date, four different lyssavirus species are the causative agents of rabies in European bats: the European Bat Lyssaviruses type 1 and 2 (EBLV-1, EBLV-2), the recently discovered putative new lyssavirus species Bokeloh Bat Lyssavirus (BBLV) and the West Caucasian Bat Virus (WCBV). Unlike in the new world, bat rabies cases in Europe are comparatively less frequent, possibly as a result of varying intensity of surveillance. Thus, the objective was to provide an assessment of the bat rabies surveillance data in Europe, taking both reported data to the WHO Rabies Bulletin Europe and published results into account. In Europe, 959 bat rabies cases were reported to the RBE in the time period 1977-2010 with the vast majority characterized as EBLV-1, frequently isolated in the Netherlands, North Germany, Denmark, Poland and also in parts of France and Spain. Most EBLV-2 isolates originated from the United Kingdom (UK) and the Netherlands, and EBLV-2 was also detected in Germany, Finland and Switzerland. Thus far, only one isolate of BBLV was found in Germany. Published passive bat rabies surveillance comprised testing of 28 of the 52 different European bat species for rabies. EBLV-1 was isolated exclusively from Serotine bats (Eptesicus serotinus and Eptesicus isabellinus), while EBLV-2 was detected in 14 Daubenton's bats (Myotis daubentonii) and 5 Pond bats (Myotis dasycneme). A virus from a single Natterer's bat (Myotis nattereri) was characterized as BBLV. During active surveillance, only oral swabs from 2 Daubenton's bats (EBLV-2) and from several Eptesicus bats (EBLV-1) yielded virus positive RNA. Virus neutralizing antibodies against lyssaviruses were detected in various European bat species from different countries, and its value and implications are discussed.
    Karpersterfte in Nederland: Nederlands instituut onderzoekt karpersterftes
    Haenen, O.L.M. ; Tulden, P.W. van; Engelsma, M.Y. - \ 2012
    Visionair : het vakblad van sportvisserij Nederland 5 (2012)23. - ISSN 1569-7533 - p. 18 - 21.
    karper - visstand - sportvissen - hengelsport - virusziekten - spring viremia of carp virus - virussen - bacteriën - parasieten - carp - fish stocks - game fishes - angling - viral diseases - spring viremia of carp virus - viruses - bacteria - parasites
    Voor veel sportvissers is karper de favoriete vissoort. Dankzij een doordacht water- en visstandbeheer kent ons land een gezonde karperpopulatie. Tocht treedt er af en toe sterfte op bij deze vissen. Mede op verzoek van Sportvisserij Nederland onderzoekt het Centraal Veterinair Instituut in Lelystad de oorzaak van deze sterftes.
    PIAMV-virus dwingt lelietelers tot maatregelen (o.a. Casper Sloot tijdens bijeenkomst voor lelietelers)
    Neefjes, H. ; Slootweg, G. - \ 2012
    Vakblad voor de Bloemisterij 67 (2012)37. - ISSN 0042-2223 - p. 34 - 35.
    bloembollen - lilium - ziektepreventie - virussen - plantago asiatica mosaic virus - testen - fytosanitaire maatregelen - landbouwkundig onderzoek - ornamental bulbs - lilium - disease prevention - viruses - plantago asiatica mosaic virus - testing - phytosanitary measures - agricultural research
    Een bom waarvan het lontje al brandt. Zo typeerde spreker Hans van der Heijden van Stichting Regionaal Onderzoek Lelie (ROL) in Noordoost Nederland de situatie rond het PIAMV-virus. Niet iedereen was zo uitgesproken op een bijeenkomst voor lelietelers in Julianadorp. De situatie is zorgelijk, dat onderkent iedereen.
    Cost Analysis of Various Low Pathogenic Avian Influenza Surveillance Systems in the Dutch Egg Layer Sector
    Rutten, N. ; Gonzales, J.L. ; Elbers, A.R. ; Velthuis, A.G.J. - \ 2012
    PLoS ONE 7 (2012)4. - ISSN 1932-6203 - 9 p.
    poultry - risk - viruses - epidemiology - netherlands - validation - chickens
    Background As low pathogenic avian influenza viruses can mutate into high pathogenic viruses the Dutch poultry sector implemented a surveillance system for low pathogenic avian influenza (LPAI) based on blood samples. It has been suggested that egg yolk samples could be sampled instead of blood samples to survey egg layer farms. To support future decision making about AI surveillance economic criteria are important. Therefore a cost analysis is performed on systems that use either blood or eggs as sampled material. Methodology/Principal Findings The effectiveness of surveillance using egg or blood samples was evaluated using scenario tree models. Then an economic model was developed that calculates the total costs for eight surveillance systems that have equal effectiveness. The model considers costs for sampling, sample preparation, sample transport, testing, communication of test results and for the confirmation test on false positive results. The surveillance systems varied in sampled material (eggs or blood), sampling location (farm or packing station) and location of sample preparation (laboratory or packing station). It is shown that a hypothetical system in which eggs are sampled at the packing station and samples prepared in a laboratory had the lowest total costs (i.e. € 273,393) a year. Compared to this a hypothetical system in which eggs are sampled at the farm and samples prepared at a laboratory, and the currently implemented system in which blood is sampled at the farm and samples prepared at a laboratory have 6% and 39% higher costs respectively. Conclusions/Significance This study shows that surveillance for avian influenza on egg yolk samples can be done at lower costs than surveillance based on blood samples. The model can be used in future comparison of surveillance systems for different pathogens and hazards
    Toetsen voor PlAMV op leven en dood - wat zegt een toetsresultaat?
    Kock, M.J.D. de - \ 2012
    BloembollenVisie 2012 (2012)241. - ISSN 1571-5558 - p. 22 - 22.
    lilium - afwijkingen, planten - diagnostische technieken - elisa - testen - virussen - plantago asiatica mosaic virus - landbouwkundig onderzoek - lilium - plant disorders - diagnostic techniques - elisa - testing - viruses - plantago asiatica mosaic virus - agricultural research
    Bij virusdiagnostiek wordt veelvuldig gebruik gemaakt van laboratoriumtoetsen. Kort nadat in 2010 bekend werd dat onbekende afwijkingen bij lelie veroorzaakt werden door PlAMV, is door PPO Bloembollen en Bloembollenkeuringsdienst (BKD) dit virus nader bestudeerd en is er een PCR-toets specifiek voor PlAMV ontwikkeld. Sinds 2011 heeft de BKD een PlAMV-specifieke ELISA-toets beschikbaar. PCR- en ELISA-toetsen worden veel bij onderzoek gebruikt. Gelukkig worden PCR- en ELISA-toetsen ook steeds vaker bij bedrijfsvoering ingezet. Dit is een goede zaak!
    TRIM proteins and CXS chemokines : evolutionary dynamics and functional characterization of two large protein families in teleost fish
    Aa, L.M. van der - \ 2012
    Wageningen University. Promotor(en): Huub Savelkoul, co-promotor(en): Lidy van Kemenade; P. Boudinot. - [S.l. : s.n. - ISBN 9789461731203 - 224
    chemokinen - teleostei - immuunsysteem - immuniteit - virussen - eiwitten - dieren - antiviruseigenschappen - chemokines - teleostei - immune system - immunity - viruses - proteins - animals - antiviral properties

    Two large protein families with roles in the immune system were the subject of this thesis. In part one of the thesis, TRIM proteins were studied, which are part of an ancient intracellular immune system. In mammals, TRIM proteins were recently found to play an important role in the antiviral immune response as they can restrict multiple viruses. To better understand the evolution of the TRIM protein family, TRIM proteins were investigated in teleost fish, which emerged early during vertebrate evolution. A detailed description of the entire TRIM gene family in fish was made and it was discovered that certain TRIM genes have undergone a radical expansion, giving rise to three multigene families. Experimental studies indicated a role for trout TRIM proteins in antiviral immunity and demonstrated that they have E3 ubiquitin ligase activity. As it recently became evident that ubiquitination is an important mode to control the activity of proteins of innate immune pathways, possibly TRIM proteins in fish have a similar activity.

    In part two of this thesis, inflammatory CXC chemokines were studied, for which limited functional data was available in fish at the start of the thesis project. CXC chemokines are specialized cytokines that direct leukocyte migration during inflammation. In zebrafish and carp, two CXC lineages were identified that resemble mammalian CXCL8, a similar diversification was observed for chemokines that resemble mammalian CXCL9, CXCL10, CXCL11chemokines. A characterization of the functions for cyprinid CXCL8-like and CXCL9-11-like (named CXCb) chemokines was made by in vitro and in vivo gene expression studies. By preparation of recombinant proteins it was demonstrated that carp chemokines of the CXCL8-like and CXCb subsets are both chemotactic for fish leukocytes. Chemokines of the CXCL8-like and CXCb subsets appeared to be functionally distinct, as they have a different effect on phagocyte activation and act during different phases of the inflammatory response. These results indicate that CXC chemokines have already specialized functions in fish.

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