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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Translocation and de novo synthesis of eicosapentaenoic acid (EPA) during nitrogen starvation in Nannochloropsis gaditana
Janssen, J.H. ; Lamers, P.P. ; Vos, C.H. de; Wijffels, R.H. ; Barbosa, M.J. - \ 2019
Algal Research 37 (2019). - ISSN 2211-9264 - p. 138 - 144.
The microalga Nannochloropsis gaditana is known for accumulating fatty acids, including the commercially interesting eicosapentaenoic acid (EPA) within the polar lipids (PL) and neutral lipids (NL). During microalgal growth EPA is mainly present in the PL. Upon nitrogen starvation N. gaditana accumulates large amounts of TAG in lipid bodies. The neutral lipid fraction will mainly consist of triacylglycerol (TAG). When expressed per total cell dry weight, the NL-localized EPA increased while the PL-localized EPA decreased, suggesting that EPA is
translocated from the PL into the NL lipids during nitrogen starvation. Here, we elucidated the origin of EPA in NL of N. gaditana by firstly growing this microalga under optimal growth conditions with 13CO2 as the sole carbon source followed by nitrogen starvation with 12CO2 as the sole carbon source. By measuring both 12C and 13C fatty acid isotope species in time, the de novo synthesized fatty acids and the already present fatty acids can be distinguished. For the first time, we proved that actual translocation of EPA from the PL into the NL occurs during nitrogen starvation of N. gaditana. Next to being translocated, EPA was synthesized de novo in both PL and NL during nitrogen starvation. EPA was made by carbon reshuffling within the cell as well. EPA was the main fatty acid translocated, suggesting that the enzyme responsible for fatty acid translocation has a high specificity for EPA.
An improved methodology to evaluate crop salt tolerance from field trials
Straten, G. van; Vos, A.C. de; Rozema, J. ; Bruning, B. ; Bodegom, P.M. van - \ 2019
Agricultural Water Management 213 (2019). - ISSN 0378-3774 - p. 375 - 387.
Crop salinity tolerance - Parameter estimation - Salinization

The salt tolerance of crops is commonly expressed in descriptive parameters such as threshold or 50%-yield soil salinity and shape parameters describing the yield curve. Estimation by visual or simplified ordinary least squares (OLS) regression methods has multiple issues: parameter bias due to uncertainty in soil salinity, lack of independent estimates of the reference yield, questionable robustness of the threshold parameter and missing information about uncertainty and correlation of the parameter estimates. Here, we present a comprehensive OLS method together with an analysis of its statistical properties to alleviate and overcome such issues, on the basis of a numerical experiment that mimics observed yield responses to saline groundwater across a range of salinities in the experimental test facility Salt Farm Texel. The results indicate under which experimental conditions bias is not a major problem. The method allows estimation of the zero-observed-effect yield from the data, which is relevant to agricultural practice. Estimates for zero-observed-effect yield and threshold ECe are negatively correlated, underlining the difficulty of obtaining reliable threshold values. The estimated confidence regions are reliable and robust against soil salinity uncertainty, but large observation error jeopardizes the confidence intervals, especially for the slope parameter. Data uncertainty alone can be responsible for substantial differences from experiment to experiment, providing a partial explanation for the wide variety in reported parameters in the literature, and stressing the need for long-term repetitions. Given the lack of robustness of the threshold parameter, we propose to adopt the 90%-yield EC (ECe90) as tolerance parameter. Its confidence bounds can be obtained from a simple reformulation of the original models. We also present uncertainty ellipses as a suitable tool to unite multiple-year estimates. The method is offered as a solid and generic basis for reliable assessment of the cultivation potential of varieties and crops on salt-affected soils.

High-Resolution Simulation Study Exploring the Potential of Radars, Crowdsourced Personal Weather Stations, and Commercial Microwave Links to Monitor Small-Scale Urban Rainfall
Vos, L.W. de; Raupach, T.H. ; Leijnse, H. ; Overeem, A. ; Berne, A. ; Uijlenhoet, R. - \ 2018
Water Resources Research (2018). - ISSN 0043-1397
microwave link - opportunistic sensing - personal weather station - simulation - small-scale - urban rainfall

Many applications in urban areas require high-resolution rainfall measurements. Typical operational weather radars can provide rainfall intensities at 1-km2 grid cells every 5 min. Opportunistic sensing with commercial microwave links yields path-averaged rainfall intensities (typically 0.1–10 km) within urban areas. Additionally, large amounts of urban in situ rainfall measurements from amateur weather observers are obtainable in real-time. The accuracy of these three techniques is evaluated for an urban study area of 20 × 20 km, taking into account their respective network layouts and sampling characteristics. We use two simulated rainfall events described in terms of drop size distributions on a 100-m grid and with a temporal resolution of 30 s. Accurate radar rainfall estimation with the Z-R relationship relies heavily on an appropriate choice of parameters, and a dual-polarization strategy is more suitable for higher intensities. Under ideal measurement conditions, the weather station network is the most promising, with a Pearson correlation coefficient above 0.86 and a relative bias below 4% for 100-m rainfall estimates at 5-min resolution. Microwave link rainfall observations contain the largest error, shown by a consistently larger coefficient of variation. The accuracy of all techniques improves when considering rainfall at larger scales, especially by increasing time intervals, with the strongest improvements found for microwave links for which errors are largely caused by their temporal sampling. Sparser networks are examined, showing that the decline in measurement accuracy only becomes significant when the link and station network density are reduced to less than half their levels in Amsterdam.

Risk of between-herd transmission of foot-and-mouth disease virus by milk collection. Interventions in wild and domestic animals: synergy or antagonism
Vos-de Jong, C.J. de; Dekker, A. - \ 2018
Risk of between-herd transmission of foot-and-mouth disease virus by milk collection
Vos-de Jong, C.J. de; Dekker, A. - \ 2018
Quantitative assessment of the infection risk for livestock when animal viruses are used in oncolytic therapy
Schijven, J.F. ; Vos-de Jong, C.J. de; Eble, P.L. ; Brizee, Sabrina ; Teunis, P.F.M. ; Rutjes, S. - \ 2018
Rapid risk assessment of exotic animal disease introduction
Vos-de Jong, C.J. de; Petie, R. ; Klink, E.G.M. van; Swanenburg, M. - \ 2018
Biological and anthropological drivers for emerging zoonoses from an interdisciplinary perspective
Swanenburg, M. ; Lauwere, C.C. de; Roest, H.I.J. ; Poel, W.H.M. van der; Boer, F. de; Vaandrager, L. ; Bergevoet, R.H.M. ; Hogeveen, H. ; Petie, R. ; Vos-de Jong, C.J. de - \ 2018
Zoonotic Risk Related to Importation of Live Animals
Tafro, N. ; Stenvers, O. ; Vos-de Jong, C.J. de; Rosa, M. De - \ 2018
Biological and anthropological drivers for emerging zoonoses from an interdisciplinary perspective
Swanenburg, M. ; Lauwere, C.C. de; Roest, H.I.J. ; Poel, W.H.M. van der; Boer, F. De; Vaandrager, L. ; Bergevoet, R.H.M. ; Hogeveen, H. ; Vos-de Jong, C.J. de - \ 2018
The European Food Safety Authority's risk assessment of vector-borne diseases: An example focusing on the risk of mosquite-borne viruses
Dhollander, S. ; Beltran-Beck, B. ; Bicout, D. ; Czwienczek, E. ; Koeijer, A.A. de; Vos-de Jong, C.J. de; Gogin, A. ; Miguel, Miranda ; Thulke, H.H. ; Stegeman, J. - \ 2018
In: Proceedings of the Annual Scientific Conference and the Annual General Meeting of the European College of Veterinary Public Health, 17-19 October 2018, University of Perugia, Italy. - Perugia : - p. 19 - 19.
Mechanistic study on trophic interaction between mucosal keystone species and butyrogenic gut commensals
Chia, L.W. ; Hornung, B.V.H. ; Aalvink, S. ; Schaap, P.J. ; Vos, W.M. de; Knol, J. ; Belzer, C. - \ 2018
PRJEB20031 - ERP022138 - Akkermansia muciniphilaAkkermansia muciniphila
Host glycans are paramount in regulating the symbiotic relationship between humans and their gut bacteria. The constant flux of host-secreted mucin at the mucosal layer creates a steady niche space for bacteria colonization. Mucin, characterized by complex molecular structure, exerts selective nutritional pressure for mucin-degrading bacteria. Mucin degradation by keystone species subsequently drives the local trophic chain and shapes mucosal microbial assembly a.k.a. mucobiome. This study investigates mucin-driven trophic interaction between the specialized mucin-degrader, Akkermansia muciniphila and butyrogenic gut commensals. Co-cultures of A. muciniphila with non-mucolytic butyrogens (Anaerostipes caccae and Eubacterium hallii) were grown in minimal media supplemented with pure mucin. Metabolites (HPLC) and meta-transcriptome (RNA-seq) were studied. Mucin degradation by A. muciniphila produced mucin-derived monosaccharides and metabolites (galactose, fucose, mannose, GlcNAc and acetate) for the growth of butyrogens (A. caccae and E. hallii) resulted in 2mM butyrate production. Interestingly, co-culture of A. muciniphila with E. hallii demonstrated mutual relationship, in which pseudovitamin B12 production by E. hallii facilitated propionate production by A. muciniphila. Cobalamin-dependent methylmalonyl-CoA mutase genes (Amuc_1983 and Amuc_1984) were upregulated in A. muciniphila monoculture, indicated the attempt by A. muciniphila to activate propionate production pathway by synthesizing more key catalytic enzymes. Differential analysis (DESeq2) showed the presence of butyrogens resulted in an altered transcriptional profile of A. muciniphila. E. hallii in particular, incurred high functional impact on A. muciniphila gene expression. Mucosal subpopulation driven by A. muciniphila could result in butyrate and propionate production. Deciphering the underlying mechanism of this microbial tropism is crucial for the understanding of mucosal health and pathophysiology.
Microbiota development in preterm and term infants
Korpela, Katri ; Blakstad, Elin W. ; Moltu, Sissel J. ; Strømmen, Kenneth ; Nakstad, Britt ; Rønnestad, Arild E. ; Brække, Kristin ; Iversen, Per O. ; Drevon, Christian A. ; Vos, W.M. de - \ 2018
PRJEB26802 - ERP108820
Microbiota development in (pre)term infants receiving various durations of postpartum antibiotic treatment. Determined through 16S rRNA gene amplicon sequencing (MiSeq, Illumina)
Genome sequence of Romboutsia lituseburensis
Gerritsen, J. ; Umanets, A. ; Leeuwen-Staneva, I.N. van; Hornung, B.V.H. ; Ritari, J. ; Paulin, L. ; Rijkers, Ger T. ; Vos, W.M. de; Smidt, H. - \ 2018
Romboutsia lituseburensis - PRJEB7306 - ERP007013
The genome of Romboutsia lituseburensis has been sequenced for comparative purposes within the new genus Romboutsia.
Genome sequence of Romboutsia str. Frifi
Gerritsen, J. ; Umanets, A. ; Leeuwen-Staneva, I.N. van; Hornung, B.V.H. ; Ritari, J. ; Paulin, L. ; Rijkers, Ger T. ; Vos, W.M. de; Smidt, H. - \ 2018
Romboutsia sp. Frifi - PRJEB7106 - ERP006791
Genome sequence of Romboutsia str. Frifi
A Bifidobacterial pilus-associated protein promotes colonic epithelial proliferation
O'Connell Motherway, Mary ; Houston, Aileen ; O'Callaghan, Grace ; Reunanen, Justus ; O'Brien, Frances ; O'Driscoll, Tara ; Casey, Patrick G. ; Vos, Willem M. de; Sinderen, Douwe van; Shanahan, Fergus - \ 2018
Molecular Microbiology (2018). - ISSN 0950-382X

Development of the human gut microbiota commences at birth, with certain bifidobacterial species representing dominant and early colonisers of the newborn gastrointestinal tract. The molecular basis of Bifidobacterium colonisation, persistence and presumed communication with the host has remained obscure. We previously identified tight adherence (Tad) pili from Bifidobacterium breve UCC2003 as an essential colonisation factor. Here, we demonstrate that bifidobacterial Tad pili also promote in vivo colonic epithelial proliferation. A significant increase in cell proliferation was detectable 5 days postadministration of B. breve UCC2003. Using advanced functional genomic approaches, bacterial strains either (a) producing the Tad2003 pili or (b) lacking the TadE or TadF pseudopilins were created. Analysis of the ability of these mutant strains to promote epithelial cell proliferation in vivo demonstrated that the pilin subunit, TadE, is the bifidobacterial molecule responsible for this proliferation response. These findings were confirmed in vitro using purified TadE protein. Our data imply that bifidobacterial Tad pili may contribute to the maturation of the naïve gut in early life through the production of a specific scaffold of extracellular protein structures, which stimulate growth of the neonatal mucosa.

Aged mice display altered numbers and phenotype of basophils, and bone marrow-derived basophil activation, with a limited role for aging-associated microbiota
Beek, Adriaan A. Van; Fransen, Floris ; Meijer, Ben ; Vos, Paul de; Knol, Edward F. ; Savelkoul, Huub F.J. - \ 2018
Immunity and Ageing 15 (2018)1.
Aging - Basophils - Bone marrow - Immunity - Microbiota - Spleen

Background: The influence of age on basophils is poorly understood, as well as the effect of aging-associated microbiota on basophils. Therefore, we studied the influence of aging and aging-associated microbiota on basophil frequency and phenotype, and differentiation from basophil precursors. Results: Basophils became more abundant in bone marrow (BM) and spleens of 19-month-old mice compared with 4-month-old mice. Aged basophils tended to express less CD200R3 and more CD123, both in BM and spleen. Differences in microbiota composition with aging were confirmed by 16S sequencing. Microbiota transfers from young and old mice to germ-free recipients revealed that CD11b tended to be lowered on splenic basophils by aging-associated microbiota. Furthermore, abundance of Alistipes, Oscillibacter, Bacteroidetes RC9 gut group, and S24-7 family positively correlated and CD123 expression, whereas Akkermansia abundance negatively correlated with basophils numbers. Subsequently, we purified FcϵRIα+CD11c-CD117- BM-derived basophils and found that those from aged mice expressed lower levels of CD11b upon stimulation. Higher frequencies of IL-4+ basophils were generated from basophil precursors of aged mice, which could be reproduced in basophils derived from germ-free recipients of aging-associated microbiota. Conclusions: Collectively, these results show the influence of aging on basophils. Furthermore, this study shows that aging-associated microbiota altered activation of BM-derived basophils in a similar fashion as observed in BM-derived basophils from aged mice.

QTL mapping of insect resistance components of Solanum galapagense
Vosman, Ben ; Kashaninia, Atiyeh ; van’t Westende, Wendy ; Meijer-Dekens, Fien ; Eekelen, Henriëtte van; Visser, Richard G.F. ; Vos, Ric C.H. de; Voorrips, Roeland E. - \ 2018
Theoretical and Applied Genetics (2018). - ISSN 0040-5752 - 11 p.

Key message: QTLs for insect resistance parameters, trichome type IV development, and more than 200 non-volatile metabolites, including 76 acyl sugars, all co-locate at the end of Chromosome 2 of Solanum galapagense. Abstract: Host plant resistance is gaining importance as more and more insecticides are being banned due to environmental concerns. In tomato, resistance towards insects is found in wild relatives and has been attributed to the presence of glandular trichomes and their specific phytochemical composition. In this paper, we describe the results from a large-scale QTL mapping of data from whitefly resistance tests, trichome phenotyping and a comprehensive metabolomics analysis in a recombinant inbred line population derived from a cross between the cultivated Solanum lycopersicum and the wild relative S. galapagense, which is resistant to a range of pest insects. One major QTL (Wf-1) was found to govern the resistance against two different whitefly species. This QTL co-localizes with QTLs for the presence of trichomes type IV and V, as well as all 76 acyl sugars detected and about 150 other non-volatile phytochemicals, including methyl esters of the flavonols myricetin and quercetin. Based on these results, we hypothesize that Wf-1 is regulating the formation of glandular trichome type IV on the leaf epidermis, enabling the production and accumulation of bioactive metabolites in this type of trichomes.

Higher Chain Length Distribution in Debranched Type-3 Resistant Starches (RS3) Increases TLR Signaling and Supports Dendritic Cell Cytokine Production
Lépine, Alexia F.P. ; Hilster, Roderick H.J. de; Leemhuis, Hans ; Oudhuis, Lizette ; Buwalda, Piet L. ; Vos, Paul de - \ 2018
Molecular Nutrition & Food Research (2018). - ISSN 1613-4125
Caco-2 - dendritic cells - resistant starches - T-cells - Toll-like receptors

Scope: Resistant starches (RSs) are classically considered to elicit health benefits through fermentation. However, it is recently shown that RSs can also support health by direct immune interactions. Therefore, it has been hypothesized that the structural traits of RSs might impact the health benefits associated with their consumption. Methods and results: Effects of crystallinity, molecular weight, and chain length distribution of RSs are determined on immune Toll-like receptors (TLRs), dendritic cells (DCs), and T-cell cytokines production. To this end, four type-3 RSs (RS3) are compared, namely Paselli WFR, JD150, debranched Etenia, and Amylose fraction V, which are extracted from potatoes and enzymatically modified. Dextrose equivalent seems to be the most important feature influencing immune signaling via activation of TLRs. TLR2 and TLR4 are most strongly stimulated. Especially Paselli WFR is a potent activator of multiple receptors. Moreover, the presence of amylose, even to residual levels, enhances DC and T-cell cytokine responses. Paselli WFR and Amylose fraction V influence T-cell polarization. Conclusions: It has been shown here that chain length and particularly dextrose equivalent are critical features for immune activation. This knowledge might lead to tailoring and design of immune-active RS formulations.

Quantitative Assessment Of The Health Risk For Livestock When Animal Viruses Are Applied in Human Oncolytic Therapy: A Case Study for Seneca Valley Virus
Schijven, Jack ; Brizee, Sabrina ; Teunis, Peter ; Vos-de Jong, C.J. de; Eble, P.L. ; Rutjes, Saskia - \ 2018
Risk Analysis (2018). - ISSN 0272-4332
Some viruses cause tumor regression and can be used to treat cancer patients; these viruses are called oncolytic viruses. To assess whether oncolytic viruses from animal origin excreted by patients pose a health risk for livestock, a quantitative risk assessment (QRA) was performed to estimate the risk for the Dutch pig industry after environmental release of Seneca Valley virus (SVV). The QRA assumed SVV excretion in stool by one cancer patient on Day 1 in the Netherlands, discharge of SVV with treated wastewater into the river Meuse, downstream intake of river water for drinking water production, and consumption of this drinking water by pigs. Dose–response curves for SVV infection and clinical disease in pigs were constructed from experimental data. In the worst scenario (four log10 virus reduction by drinking water treatment and a farm with 10,000 pigs), the infection risk is less than 1% with 95% certainty. The risk of clinical disease is almost seven orders of magnitude lower. Risks may increase proportionally with the numbers of treated patients and days of virus excretion. These data indicate that application of wild‐type oncolytic animal viruses may infect susceptible livestock. A QRA regarding the use of oncolytic animal virus is, therefore, highly recommended. For this, data on excretion by patients, and dose–response parameters for infection and clinical disease in livestock, should be studied.
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