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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    On the sensitivity of local flexibility markets to forecast error : A bi-level optimization approach
    Azari, Delaram ; Torbaghan, Shahab Shariat ; Cappon, Hans ; Keesman, Karel J. ; Gibescu, Madeleine ; Rijnaarts, Huub - \ 2020
    Energies 13 (2020)8. - ISSN 1996-1073
    Bi-level optimization - Optimal flexibility dispatch - Sensitivity analysis - Transactive energy

    The large-scale integration of intermittent distributed energy resources has led to increased uncertainty in the planning and operation of distribution networks. The optimal flexibility dispatch is a recently introduced, power flow-based method that a distribution system operator can use to effectively determine the amount of flexibility it needs to procure from the controllable resources available on the demand side. However, the drawback of this method is that the optimal flexibility dispatch is inexact due to the relaxation error inherent in the second-order cone formulation. In this paper we propose a novel bi-level optimization problem, where the upper level problem seeks to minimize the relaxation error and the lower level solves the earlier introduced convex second-order cone optimal flexibility dispatch (SOC-OFD) problem. To make the problem tractable, we introduce an innovative reformulation to recast the bi-level problem as a non-linear, single level optimization problem which results in no loss of accuracy. We subsequently investigate the sensitivity of the optimal flexibility schedules and the locational flexibility prices with respect to uncertainty in load forecast and flexibility ranges of the demand response providers which are input parameters to the problem. The sensitivity analysis is performed based on the perturbed Karush-Kuhn-Tucker (KKT) conditions. We investigate the feasibility and scalability of the proposed method in three case studies of standardized 9-bus, 30-bus, and 300-bus test systems. Simulation results in terms of local flexibility prices are interpreted in economic terms and show the effectiveness of the proposed approach.

    Comparative Greenhouse Gas Footprinting of Online versus Traditional Shopping for Fast-Moving Consumer Goods : A Stochastic Approach
    Shahmohammadi, Sadegh ; Steinmann, Zoran J.N. ; Tambjerg, Lau ; Loon, Patricia van; King, J.M.H. ; Huijbregts, Mark A.J. - \ 2020
    Environmental Science and Technology 54 (2020)6. - ISSN 0013-936X - p. 3499 - 3509.

    Variability in consumer practices and choices is typically not addressed in comparisons of environmental impacts of traditional shopping and e-commerce. Here, we developed a stochastic model to quantify the variability in the greenhouse gas (GHG) footprints of product distribution and purchase of fast-moving consumer goods (FMCGs) via three prevalent retail channels in the United Kingdom (U.K.). We found that shopping via bricks and clicks (click and fulfillment via physical store delivery) most likely decreases the GHG footprints when substituting traditional shopping, while FMCGs purchased through pure players with parcel delivery often have higher GHG footprints compared to those purchased via traditional retail. The number of items purchased and the last-mile travel distance are the dominant contributors to the variability in the GHG footprints of all three retail channels. We further showed that substituting delivery vans with electric cargo bikes can lead to a GHG emission reduction of 26% via parcel delivery. Finally, we showed the differences in the "last mile" GHG footprint of traditional shopping in the U.K. compared to three other countries (China, Netherlands, and the United States), which are primarily caused by the different shares of modes of transport (walking and by car, bus, and bike).

    Novel COX-2 products of n-3 polyunsaturated fatty acid-ethanolamine-conjugates identified in RAW264.7 macrophages
    Bus, Ian de; Zuilhof, Han ; Witkamp, Renger ; Balvers, Michiel ; Albada, Bauke - \ 2019
    Journal of Lipid Research 60 (2019)11. - ISSN 0022-2275 - p. 1829 - 1840.
    cyclooxygenase - cyclooxygenase 2 - fatty acid amides - fatty acid oxidation - high-performance liquid chromatography - inflammation - mass spectrometry - prostaglandins

    Cyclooxygenase 2 (COX-2) plays a key role in the regulation of inflammation by catalyzing the oxygenation of PUFAs to prostaglandins (PGs) and hydroperoxides. Next to this, COX-2 can metabolize neutral lipids, including endocannabinoid-like esters and amides. We developed an LC-HRMS-based human recombinant (h)COX-2 screening assay to examine its ability to also convert n-3 PUFA-derived N-acylethanolamines. Our assay yields known hCOX-2-derived products from established PUFAs and anandamide. Subsequently, we proved that eicosapentaenoylethanolamide (EPEA), the N-acylethanolamine derivative of EPA, is converted into PGE3-ethanolamide (PGE3-EA), and into 11-, 14-, and 18-hydroxyeicosapentaenoyl-EA (11-, 14-, and 18-HEPE-EA, respectively). Interestingly, we demonstrated that docosahexaenoylethanolamide (DHEA) is converted by hCOX-2 into the previously unknown metabolites, 13- and 16-hydroxy-DHEA (13- and 16-HDHEA, respectively). These products were also produced by lipopolysaccharide-stimulated RAW267.4 macrophages incubated with DHEA. No oxygenated DHEA metabolites were detected when the selective COX-2 inhibitor, celecoxib, was added to the cells, further underlining the role of COX-2 in the formation of the novel hydroxylated products. This work demonstrates for the first time that DHEA and EPEA are converted by COX-2 into previously unknown hydroxylated metabolites and invites future studies toward the biological effects of these metabolites.

    The role of n-3 PUFA-derived fatty acid derivatives and their oxygenated metabolites in the modulation of inflammation
    Bus, Ian de; Witkamp, Renger ; Zuilhof, Han ; Albada, Bauke ; Balvers, Michiel - \ 2019
    Prostaglandins and Other Lipid Mediators 144 (2019). - ISSN 1098-8823
    Chemical probes - Endocannabinoid - Inflammation - Oxygenation - PUFA

    Notwithstanding the ongoing debate on their full potential in health and disease, there is general consensus that n-3 PUFAs play important physiological roles. Increasing dietary n-3 PUFA intake results in increased DHA and EPA content in cell membranes as well as an increase in n-3 derived oxylipin and -endocannabinoid concentrations, like fatty acid amides and glycerol-esters. These shifts are believed to (partly) explain the pharmacological and anti-inflammatory effects of n-3 PUFAs. Recent studies discovered that n-3 PUFA-derived endocannabinoids can be further metabolized by the oxidative enzymes CYP-450, LOX and COX, similar to the n-6 derived endocannabinoids. Interestingly, these oxidized n-3 PUFA derived endocannabinoids of eicosapentaenoyl ethanolamide (EPEA) and docosahexaenoyl ethanolamide (DHEA) have higher anti-inflammatory and anti-proliferative potential than their precursors. In this review, an overview of recently discovered n-3 PUFA derived endocannabinoids and their metabolites is provided. In addition, the use of chemical probes will be presented as a promising technique to study the n-3 PUFA and n-3 PUFA metabolism within the field of lipid biochemistry.

    Planty Organic: voortgang 2018
    Burgt, G.J. van der; Rietema, C. ; Bus, M. ; Timmermans, B.G.H. - \ 2019
    Driebergen : Louis Bolk Instituut - 45 p.
    Planty Organic is a project and an experimental field in which an arable farming system is developed based on 100% nitrogen input by fixation and non-ploughing. It is started in 2012. An evaluation report has been published (Van der Burgt et al., 2017b) on the period 2012-2016. The system can be used to earn new knowledge that can be applied in the organic or conventional agriculture, on the themes of nitrogen-, phosphorus- or soil-dynamics.This report focuses on the 2018 practice and results, referring to the evaluation report. The 2018 experiences confirm the system performance as described in the evaluation. All goals are achieved: it is a productive system with a high nitrogen efficiency and a very low environmental and climate impact.The production in 2017 was roughly the level as it is expected in the evaluation. This is confirmed in a system simulation with the Ndicea model. It is not plausible that the 2017 production level will be continuously realized. Research questions remain on the internal nutrient dynamics (nitrogen and phosphorus), soil life, rooting systems and CO2 footprint.
    Natuurbeleving 2.0: de potentie van digitale natuurbelevingen
    Bade, Dagmar ; Bus, Anne ; Breman, B.C. - \ 2019
    Wageningen : Nature Today
    Invited review: abomasal damage in veal calves
    Bus, J.D. ; Stockhofe, N. ; Webb, L.E. - \ 2019
    Journal of Dairy Science 102 (2019)2. - ISSN 0022-0302 - p. 943 - 960.
    abomasal damage - etiology - risk factor - veal calf

    Within all cattle production systems, veal calves are the most severely affected by abomasal damage, with current prevalence at slaughter ranging from 70 to 93% of all animals affected. Although most damage is found in the pyloric region of the abomasum, fundic lesions are also found. Despite past research into the etiology of abomasal damage and the many risk factors that have been proposed, consensus on the causal factors of abomasal damage in veal calves has not yet been reached. The aim of this review was to integrate and analyze available information on the etiology of, and possible risk factors for, abomasal damage in veal calves. We describe various proposed pathways through which risk factors may contribute to damage formation and conclude that the etiology of abomasal damage is most likely multifactorial, with diet being a main contributor. Pyloric lesions, the most common type of damage in veal calves, are likely the result of large and infrequent milk and solid feed meals, whereas fundic lesions may be caused by stress, although the evidence for this is inconclusive. Providing calves with multiple smaller milk and solid feed meals (or ad libitum provision) may decrease abomasal damage. In future research, ulcers, erosions, and scars as well as fundic and pyloric lesions should be recorded separately, because etiologies of these may differ. Further research is required to understand the exact pathway(s) by which milk replacer causes abomasal damage in veal calves; that is, whether low abomasal pH, overloading, or composition are important. Further research is also required to elucidate whether rapid intake of milk replacer and solid feed, which is influenced by restricted amounts fed, inter-calf competition, and calf breed, increases abomasal damage. Research is also needed into the effect of medication and nutrient deficiencies other than iron. The types of experimental designs that can be used for future research could be enhanced if a means to assess abomasal damage antemortem is developed. We conclude that it is unlikely that abomasal or ruminal hairballs, iron deficiency, water provision, and various infections and diseases are significant contributors to abomasal damage in veal calves.

    Novel insights in the molecular mechanisms of action of retinoids and their potential repercussions on breast cancer cell proliferation
    Miro Estruch, Ignacio - \ 2018
    Wageningen University. Promotor(en): I.M.C.M. Rietjens; J.P. Groten, co-promotor(en): J. Louisse. - Wageningen : Wageningen University - ISBN 9789463432788 - 280

    In chapter 1 of this thesis, background information on the molecular actions and effects elicited by retinoids in the context of nuclear receptor (NR) signaling and breast cancer treatment was given. In addition, the state of the art and the knowledge gap still remaining in this area was highlighted. The principal objective of the thesis was defined which was to investigate different molecular events possibly elicited after retinoid treatment to better understand the observed effects on breast cancer cell proliferation Finally, the general outline of the present thesis was provided.

    Chapter 2 assessed whether the ligand binding domain (LBD) of the Retinoic Acid Receptor (RAR) can be used to study RAR-coregulator binding events as an alternative to the use of the full length (FL) RAR. Thus, this work aimed to characterize and compare ligand-driven coregulator interactions of both the RARα-LBD and the RARα-FL. We studied the coregulator motif interactions of RARα-FL and RARα-LBD upon incubation with the RAR agonist all-trans retinoic acid (AtRA) and the RAR antagonist Ro415253 using the Microarray Assay for Real-time Coregulator-Nuclear Receptor Interaction (MARCoNI). The results obtained showed that the coregulator binding profiles are highly similar for the RARα-FL and the RARα-LBD regarding both qualitative aspects like the type of coregulators that bind or dissociate upon (ant)agonist action and quantitative parameters such as EC50s and the maximum responses (modulation indexes at saturating ligand concentration). Moreover, based on the coregulator binding signatures, the RAR agonist AtRA could be clearly discriminated from the RAR antagonist Ro415253 using both the RARα-FL and the RARα-LBD.

    Once established that coregulator binding patterns could be adequately characterised using LBDs, Chapter 3 assessed the coregulator binding profiles of the LBDs belonging to the RAR alpha (RARα), beta (RARβ) and gamma (RARγ) focusing on possible differential outcomes between the different RARs. To this end, this study used the MARCoNI coregulator binding assay to characterize coregulator motif binding patterns of the distinct RAR subtypes upon incubation with the general agonist all-trans-Retinoic Acid (AtRA); the subtype-selective agonists Am80 (RARα), CD2314 (RARβ) and BMS961 (RARγ); and the antagonist Ro415253. Chapter 3 showed multiple ligand-dependent RAR-coregulator interactions for all RARs, including binding events not described before. It also confirmed a greater ligand-independent functioning of RARβ based on both higher basal and lower ligand-induced coregulator binding. In addition, despite the generally high similarity, various coregulator motifs showed subtype-selective binding, providing a basis for a potential role of coregulator binding in the receptor subtype-specific responses. Finally, Chapter 3 also proved that subtype-selective agonists and agonistic/antagonistic actions of ligands for all the RAR variants can be easily discriminated by the MARCoNI coregulator binding assay.

    After characterizing a possible role of coregulator binding in RAR subtype-specific responses, in chapter 4 and chapter 5 of this thesis, the crosstalk between retinoid and estrogen signaling in the estrogen receptor positive (ER+) breast cancer MCF7/BUS cell line was investigated. To this end, in chapter 4, the effects of AtRA on the basal and E2-induced estrogen receptor alpha (ERα) signaling were characterised using the MCF7/BUS and the U2OS-ERα-Luc cell lines. The effects of AtRA on different ERα-related events such as ERα-mediated cell proliferation and gene expression, ERα-coregulator binding and ERα subcellular localization were evaluated. While AtRA-driven inhibition of E2-induced signalling was found in the proliferation and gene expression studies, no significant effects on the E2-directed coregulator binding and subcellular distribution of ERα were observed. Strikingly, chapter 4 showed that in the absence of E2, basal ERα-mediated gene expression, ERα-coregulator binding (in lysate samples) and ERα nuclear localization were increased when exposing the cells to micromolar concentrations of AtRA. However, further coregulator binding assays making use of isolated ERα-LBDs suggested that direct binding of AtRA to ERα does not take place so that other molecular mechanisms must be involved in this phenomenon, which must be studied in the future.

    In Chapter 5 the studies performed in chapter 4 using AtRA were extended to the RAR subtype-selective ligands. Thus, it was investigated whether the distinct effects of RAR subtype-selective agonists on breast cancer cell proliferation could partially be driven by differential effects on the ERα pathway. To test that hypothesis, evaluation of the effects driven by the general agonist AtRA and the subtype-selective agonists Am80 (RARα), CD2314 (RARβ) and BMS961 (RARγ) on basal ERα-related events was carried out using the MCF7/BUS and the U2OS-ERα-Luc cell lines. The results obtained indicated that proliferation, ERα-mediated gene expression, ERα-coregulator binding and ERα subcellular localization can be affected by some of the retinoids in a compound-specific manner. Nonetheless, the responses did not reveal a clear distinction between the different effective (anti-proliferative) AtRA and Am80 and the more ineffective retinoids CD2314 and BMS961. In addition, the coregulator binding studies with the isolated ERα-LBD showed that none of the compounds modulated ERα by direct binding (ligand-receptor) suggesting other pathways as underlying causal factors of the distinct effects of RAR subtype-selective ligands on ERα signaling. From all retinoids tested, the general RAR-agonist AtRA and the RARβ agonist CD2314 displayed the most remarkable effects on ERα signaling. Upon AtRA and CD2314 treatment at micromolar concentrations up-regulation of ER-mediated transcription was observed. However these retinoids differed when comparing other ERα-related molecular events. Thus, while AtRA increased ERα nuclear localization and coregulator binding, CD2314 exerted no significant effects on these molecular endpoints.

    To obtain further insight in the crosstalk between retinoid and estrogen signaling in breast cancer, in chapter 6 of the present thesis, the effects of the general RAR agonist AtRA on the cell proliferation and the related gene expression profiles upon treatment with E2 were studied in the ER+ breast cancer cell line T47D. For this purpose, different assays determining the effects on cell proliferation and the transcriptomic pattern (RNA-seq) were used. In addition, the effects of AtRA on the specific ERα- and ERβ-mediated gene expression were assessed by means of reporter gene assays with the T47D-ERα-Luc and U2OS-ERβ-Luc cell lines. The results obtained from the proliferation and reporter gene studies pointed at AtRA as a repressor of the E2-induced breast cancer growth and as inhibitor of the E2-driven expression mediated by ERα and ERβ. To further understand the underlying modes of action of RAR-ER crosstalk, in a next step chapter 6 acquired further insights on the possible interplay between estrogen and retinoid signalling by means of a transcriptomic analysis. A high proportion of estrogen-responsive genes were found to be modulated by a single treatment with AtRA. In addition, RNA-seq data showed that AtRA can exert a variable modulation of the E2-induced transcriptomic responses. In other words, AtRA both counteracted and enhanced gene expression responses induced by E2. Further analysis showed that the estrogen-responsive genes whose E2-driven expression was counteracted upon co-exposure to AtRA were more often related to biological processes involved in breast cancer cell proliferation, differentiation or apoptosis. Altogether, the results of chapter 6 supported the existence of genomic crosstalk between estrogen and retinoid signaling eliciting distinct responses depending on the gene considered. However, co-treatment with AtRA more frequently presented inhibiting/counteracting effects on E2-induced genes involved in breast cancer growth.

    In Chapter 7, the studies assessing the effects of the general agonist AtRA on the proliferation and related transcriptomic patterns in the T47D breast cancer cell line were extended to the RAR subtype-selective agonists. The effects of the different retinoids on RAR or other NR pathways of importance in breast cancer cell proliferation (e.g. ER pathway) were assessed by analyzing gene expression patterns. This study showed that the general AtRA and the RARα agonist Am80 highly hampered T47D breast cancer cell proliferation while the RARβ agonist CD2314 and the RARγ agonist BMS961 showed to be ineffective anticancer agents which even slightly increased proliferative rates. The transcriptomic profiles clearly differentiated between the effective and ineffective retinoids showing multiple differences in gene expression. Chapter 7 also suggested RARα as the main RAR subtype involved in the effects of retinoids on gene expression as shown by the higher and relatively similar effects observed on the transcriptomic signature elicited by AtRA and Am80. Differences between the anti-proliferative retinoids (AtRA and Am80) and the ineffective retinoids (CD2314 and BMS961) mainly occurred in terms of magnitude of expression. Thus, relevant biological processes such as proliferation, differentiation and apoptosis and pathways such as the RAR, the ER, the VDR and the GR pathways were differentially modulated by the effective and ineffective retinoids. Altogether, the main conclusion drawn in this chapter was that small differences in effects on multiple pathways regulating breast cancer cell proliferation may sum up leading to the distinct responses elicited by the different retinoids in T47D breast cancer cells.

    Finally, in Chapter 8 we first provided an overview on the principal results generated throughout the present thesis. Next, we went in detail with a discussion of all the findings of the thesis. In this analysis, comparison with previous literature, implications of the results obtained and follow-up studies to be performed in the future, were incorporated.

    The effects of all-trans retinoic acid on estrogen receptor signaling in the estrogen-sensitive MCF/BUS subline
    Miro Estruch, Ignacio ; Haan, Laura H.J. de; Melchers, Diana ; Houtman, René ; Louisse, Jochem ; Groten, John P. ; Rietjens, Ivonne M.C.M. - \ 2018
    Journal of Receptors and Signal Transduction 38 (2018)2. - ISSN 1079-9893 - p. 112 - 121.
    breast cancer - coregulator - crosstalk - ERα - proliferation - RAR
    Estrogen receptor alpha (ERα) and retinoic acid receptors (RARs) play important and opposite roles in breast cancer growth. While exposure to ERα agonists such as 17β-estradiol (E2) is related to proliferation, RAR agonists such as all-trans retinoic acid (AtRA) induce anti-proliferative effects. Although crosstalk between these pathways has been proposed, the molecular mechanisms underlying this interplay are still not completely unraveled. The aim of this study was to evaluate the effects of AtRA on ERα-mediated signaling in the ERα positive cell lines MCF7/BUS and U2OS-ERα-Luc to investigate some of the possible underlying modes of action. To do so, this study assessed the effects of AtRA on different ERα-related events such as ERα-mediated cell proliferation and gene expression, ERα-coregulator binding and ERα subcellular localization. AtRA-mediated antagonism of E2-induced signaling was observed in the proliferation and gene expression studies. However, AtRA showed no remarkable effects on the E2-driven coregulator binding and subcellular distribution of ERα. Interestingly, in the absence of E2, ERα-mediated gene expression, ERα-coregulator binding and ERα subcellular mobilization were increased upon exposure to micromolar concentrations of AtRA found to inhibit cell proliferation after long-term exposure. Nevertheless, experiments using purified ERα showed that direct binding of AtRA to ERα does not occur. Altogether, our results using MCF7/BUS and U2OS-ERα-Luc cells suggest that AtRA, without being a direct ligand of ERα, can indirectly interfere on basal ERα-coregulator binding and basal ERα subcellular localization in addition to the previously described crosstalk mechanisms such as competition of ERs and RARs for DNA binding sites.
    Highly Specific Binding on Antifouling Zwitterionic Polymer-Coated Microbeads as Measured by Flow Cytometry
    Andel, Esther Van; Bus, Ian De; Tijhaar, Edwin J. ; Smulders, Maarten M.J. ; Savelkoul, Huub F.J. ; Zuilhof, Han - \ 2017
    ACS Applied Materials and Interfaces 9 (2017)44. - ISSN 1944-8244 - p. 38211 - 38221.
    antifouling - biosensing - flow cytometry - microbead - sulfobetaine - zwitterionic polymer
    Micron- and nano-sized particles are extensively used in various biomedical applications. However, their performance is often drastically hampered by the nonspecific adsorption of biomolecules, a process called biofouling, which can cause false-positive and false-negative outcomes in diagnostic tests. Although antifouling coatings have been extensively studied on flat surfaces, their use on micro- and nanoparticles remains largely unexplored, despite the widespread experimental (specifically, clinical) uncertainties that arise because of biofouling. Here, we describe the preparation of magnetic micron-sized beads coated with zwitterionic sulfobetaine polymer brushes that display strong antifouling characteristics. These coated beads can then be equipped with recognition elements of choice, to enable the specific binding of target molecules. First, we present a proof of principle with biotin-functionalized beads that are able to specifically bind fluorescently labeled streptavidin from a complex mixture of serum proteins. Moreover, we show the versatility of the method by demonstrating that it is also possible to functionalize the beads with mannose moieties to specifically bind the carbohydrate-binding protein concanavalin A. Flow cytometry was used to show that thus-modified beads only bind specifically targeted proteins, with minimal/near-zero nonspecific protein adsorption from other proteins that are present. These antifouling zwitterionic polymer-coated beads, therefore, provide a significant advancement for the many bead-based diagnostic and other biosensing applications that require stringent antifouling conditions.
    Revealing Curitiba's flawed sustainability : How discourse can prevent institutional change
    Giacomini Martínez, Joyde ; Boas, Ingrid ; Lenhart, Jennifer ; Mol, Arthur P.J. - \ 2016
    Habitat International 53 (2016). - ISSN 0197-3975 - p. 350 - 359.
    Brazil - City planning - Discursive institutionalism - Institutional change - Urban sustainability

    The city of Curitiba, Brazil, is considered an exceptional model of sustainable urban planning. It has received praise for its invention of the Bus Rapid Transit System and numerous awards identify Curitiba as one of the world's greenest cities. Controversial elements have, however, been left out of this hegemonic city discourse, along with inevitable new challenges. The aim of this article is two-fold. First, we assess whether Curitiba is living up to its reputation as a leading sustainable city by analyzing three areas of urban sustainable development: green spaces, water bodies and public transportation. We show how Curitiba experiences problems ranging from social exclusion resulting from green space policies, to polluted water bodies and hampered planning in the area of public transportation. Second, we examine how the Curitiba discourse as a leading sustainable city is able to endure in this changed material context. We demonstrate how this hegemonic discourse prevents institutional transformations: the discourse becomes reproduced by powerful networks and propaganda, masking new unsustainable realities and by the same token preventing fast and successful institutional renewal.

    Scab resistance in ‘Geneva’ apple is conditioned by a resistance gene cluster with complex genetic control
    Bastiaanse, H. ; Bassett, H.C.M. ; Kirk, C. ; Gardiner, S.E. ; Deng, C. ; Groenwold, R. ; Chagné, D. ; Bus, V.G.M. - \ 2016
    Molecular Plant Pathology 17 (2016)2. - ISSN 1464-6722 - p. 159 - 172.
    Apple scab, caused by the fungal pathogen Venturia inaequalis, is one of the most severe diseases of apple worldwide. It is the most studied plant-pathogen interaction involving a woody species using modern genetic, genomic, proteomic and bioinformatic approaches in both species. Although ‘Geneva’ apple was recognised long ago as a potential source of resistance to scab, this resistance has not been previously characterised. Differential interactions between various monoconidial isolates of V. inaequalis and six segregating F1 and F2 populations indicate the presence of at least five loci governing the resistance in ‘Geneva’. The 17 chromosomes of apple were screened using genotyping-by-sequencing, as well as single marker mapping to position loci controlling the V. inaequalis resistance on linkage group 4. Next, we fine-mapped a 5 cM region containing five loci conferring both dominant and recessive scab resistance to the distal end of the linkage group. This region corresponds to 2.2 Mbp (from 20.3 to 22.5 Mbp) on the physical map of ‘Golden Delicious’ containing nine candidate NBS-LRR resistance genes. This study increases our understanding of the complex genetic basis of apple scab resistance conferred by ‘Geneva’ as well as the gene-for-gene (GfG) relationships between the effector genes in the pathogen and resistance genes in the host.
    Look mum, no hands!
    IJsselmuiden, Joris ; Vroegindeweij, Bastiaan - \ 2015

    What a strange sight it will be: a vehicle without a driver. A bus that travels on public roads and across the campus with only passengers - how is that possible? Is it safe? And who can use this bus, or rather, who dares?

    Virulence characterization of Venturia inaequalis reference isolates on the differential set of Malus hosts
    Caffier, V. ; Patocchi, A. ; Expert, P. ; Bellanger, M.N. ; Durel, C.E. ; Hilber-Bodmer, M. ; Broggini, G.A.L. ; Groenwold, R. ; Bus, V. - \ 2015
    Plant Disease 99 (2015)3. - ISSN 0191-2917 - p. 370 - 375.
    A set of differential hosts has recently been identified for 17 apple scab resistance genes in an updated system for defining gene-for-gene (GfG) relationships in the Venturia inaequalis-Malus pathosystem. However, a set of reference isolates characterized for their complementary avirulence alleles is not yet available. In this paper, we report on improving the set of differential hosts for h(7) and propose the apple genotype LPG3-29 as carrying the single major resistance gene Rvi7. We characterized a reference set of 23 V. inaequalis isolates on 14 differential apple hosts carrying major resistance genes under controlled conditions. We identified isolates that were virulent on at least one of the following defined resistance gene hosts: h(1), h(2), h(3), h(4), h(5), h(6), h(7), h(8), h(9), h(10) and h(13). Sixteen different virulence patterns were observed. In general, the isolates carried one to three virulences, but some of them were more complex, with up to six virulences. This set of well-characterized isolates will be helpful for the identification of additional apple scab resistance genes in apple germplasm and the characterization of new GfG relationships to help improve our understanding of the host-pathogen interactions in the V. inaequalis-Malus pathosystem.
    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).
    PlantyOrganic - Results 2013
    Hospers-Brands, A.J.T.M. ; Anema, J.R. ; Bus, M. - \ 2014
    Driebergen : Louis Bolk Instituut - 33
    akkerbouw - bemesting - stikstof - groenbemesters - dekgewassen - teeltsystemen - biologische landbouw - agrarische bedrijfsvoering - duurzaamheid (sustainability) - bodemvruchtbaarheid - groenteteelt - veldgewassen - arable farming - fertilizer application - nitrogen - green manures - cover crops - cropping systems - organic farming - farm management - sustainability - soil fertility - vegetable growing - field crops
    This report is the second in a series about the development of a farming system without external input of minerals or nitrogen. The first report described the design of the system, and the results of the first experimental year, 2012. The report you are now reading describes the results of 2013, the second experimental year.
    ‘Schmidt's Antonovka’ is identical to ‘Common Antonovka’, an apple cultivar widely used in Russia in breeding for biotic and abiotic stresses
    Pikunova, A. ; Madduri, M. ; Sedov, E. ; Noordijk, Y. ; Peil, A. ; Troggio, M. ; Bus, V.G.M. ; Visser, R.G.F. ; Weg, W.E. van de - \ 2014
    Tree Genetics and Genomes 10 (2014)2. - ISSN 1614-2942 - p. 261 - 271.
    x-domestica borkh. - resistance gene - linkage map - scab - genome
    Progenies of ‘Schmidt's Antonovka’ (SA) have been widely used in Western breeding programs as a source of scab resistance. The identity of SA has remained obscure, especially due to the existence of a series of ‘Antonovka’ cultivars with different origins. In this paper we show Schmidt's Antonovka to be identical to ¿¿¿¿´¿¿¿¿¿ ¿¿¿¿¿¿¿¿¿¿¿¿ or ‘Common Antonovka’ (CA), an old Russian cultivar of unknown origin, by comparing simple sequence repeat (SSR) and SNP genotyping data from several first-generation descendants of SA from two European collections and a CA accession from the germplasm collection held at VNIISPK (The All-Russian Research Institute of Horticultural Breeding, Orel, Russia). The use of CA in Russian breeding programs is also briefly reviewed.
    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. - \ 2012
    Wageningen : Plant Research International, Business Unit Biointeracties en Plantgezondheid - 40
    akkerbouw - aardappelen - aardappelvirus y - besmetters - waardplanten - aphididae - virus-gastheer interacties - vectoren - gewasbescherming - plantenvirussen - arable farming - potatoes - potato virus y - contaminants - host plants - aphididae - virus-host interactions - vectors - plant protection - plant viruses
    Mogelijke bronnen van besmettingen met het aardappelvirus Y (PVY) in aardappelen. In dit onderzoek is met name gekeken naar de rol van bladluizen als belangrijkste overbrengers (‘vectoren’) van PVY. Daarnaast is gekeken naar het mogelijk voorkomen van het virus in andere planten (m.n. onkruiden).
    Automatisch onkruid bestrijden in de gewasrij : rapport PPL Fase4C-II: doorontwikkelen van hardware en software
    Hemming, J. ; Nieuwenhuizen, A.T. ; Struik, L. - \ 2012
    Wageningen : Plant Research International, Business Unit Agrosysteemkunde - 13
    precisielandbouw - akkerbouw - gewasbescherming - onkruidbestrijding - computer hardware - software-ontwikkeling - teelt in rijen - geografische informatiesystemen - sensors - gegevensverwerking - precision agriculture - arable farming - plant protection - weed control - computer hardware - software engineering - alley cropping - geographical information systems - sensors - data processing
    Alle in deze fase geplande activiteiten zijn uitgevoerd volgens projectplan. Het user interface is aangepast voor gemakkelijk gebruik door de eindgebruiker en geheel in de huisstijl van Steketee. Er is overgestapt naar een ander type microcontroller met CAN bus interface waardoor de communicatie tussen high-level PC, sensoren en actuatoren sneller en robuuster verloopt. Op de machine is een remote service verbinding aangelegd zodat van afstand met de eindgebruiker kan worden meegekeken bij het oplossen van problemen en het maken van instellingen. De softwarealgoritmes voor plantdetectie zijn aangepast zodat beter om de gewasplanten heen geschoffeld kan worden. Een mechanische hoogteregeling van de machine is in hardware en software gerealiseerd en getest. Hierdoor kan de afstand van de camera’s t.o.v. van het gewas constant worden gehouden wat de beeldkwaliteit ten goede
    Inventory of possible crop cultivation changes as a result of the introduction of GM crops in the Maritime zone of Europe - An overview for Maize, Sugar beet and Potato
    Riemens, M.M. ; Wiel, C.C.M. van de; Brink, L. van den; Bus, C.B. ; Lotz, L.A.P. - \ 2012
    Wageningen : PRI (Report / Plant Research International 489)
    genetische modificatie - akkerbouw - maïs - aardappelen - suikerbieten - west-europa - verandering - introductie - genetic engineering - arable farming - maize - potatoes - sugarbeet - western europe - change - introduction
    Dit rapport is het resultaat van een project waarin getracht werd de volgende onderzoeksvraag van de COGEM te beantwoorden: welke teeltveranderingen kunnen in de maritieme zone van Europa verwacht worden na een mogelijke introductie van genetisch gemodificeerde (GG) maïs, aardappel en suikerbiet?
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