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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Effect of meat processing on viability of Toxoplasma gondii: Towards replacement of mouse bioassay by in vitro testing
Opsteegh, M. ; Dam-Deisz, C. ; Boer, P. de; Fare, A. ; Hengeveld, P. ; Luiten, R. ; Smits, C.B. ; Verkleij, T. ; Giessen, Judith van der; Wisselink, H.J. - \ 2019
Felines are the definitive hosts of T. gondii and primary infection results in fecal shedding of infectious oocysts. Infected intermediate hosts will develop tissue cysts, which are infective to both cats and intermediate hosts. Meat containing viable tissue cysts is considered one of the main sources of human infection. In contrast to fresh meat, raw meat products usually undergo processing, including salting and mixing in additives such as acetate and lactate, which affects the viability of T. gondii. However, the experiments currently described in literature, are not always performed in line with the processing methods applied in industry. Therefore we aimed to study the effect of salting and additives according to the recipes used by commercial producers. Mouse or cat bioassay is the gold standard to demonstrate the presence of viable T. gondii. However, it is costly, time consuming and for ethical reasons not preferred for large-scale studies. Therefore, our second aim was to develop an alternative for mouse bioassay that can be used to determine the effect of processing on the viability of T. gondii tissue cysts. We focused on a tissue culture method to determine the parasite's ability to multiply, and a PMA-based assay to selectively detect DNA from live cells. Results with the PMA-based method were inconsistent and did not sufficiently discriminate between live and dead parasites. The tissue culture method showed promising results, but further optimization is needed before it can replace or reduce the number of mouse bioassays needed. Small scale experiments with minced meat incubated for 20h with low concentrations of salt, lactate and acetate showed a large but incomplete reduction of the number of infected mice. In future, in vitro methods are needed to allow more extensive testing of product-specific processing methods, thereby providing a better indication of the risk of T. gondii infection for consumers.
Clonal expansion of a virulent Streptococcus suis serotype 9 lineage distinguishable from carriage subpopulations
Willemse, Niels ; Ark, Kees C.H. van der; Stockhofe-Zurwieden, Norbert ; Smith, Hilde ; Picavet, Daisy I. ; Solt-Smits, Conny van; Wisselink, Henk J. ; Schultsz, Constance ; Greeff, Astrid de - \ 2019
Scientific Reports 9 (2019)1. - ISSN 2045-2322

Streptococcus suis is a porcine pathogen, causing severe invasive infections. S. suis serotype 9 is increasingly causing disease in Dutch and Chinese pig herds, but it is unknown whether all serotype 9 isolates are equally virulent and markers that can identify virulent strains are not available. Therefore, discrimination between virulent isolates and carriage isolates typically not associated with disease, is currently not possible. We collected tonsillar S. suis isolates from 6 herds not previously diagnosed with S. suis infections, and clinical S. suis isolates of previously diseased pigs. We confirmed the virulence of a virulent type strain and one representative clinical isolate, and the lack of virulence of two carriage isolates, in a pig infection model. Phylogenetic analysis of whole genome sequences of 124 isolates resulted in 10 groups, of which two were almost uniquely populated by clinical isolates. The population structure of S. suis serotype 9 appears highly diverse. However, analysis of the capsule loci sequences showed variation in a single region which fully correlated with a virulent genotype. Transmission electron microscopy suggested differences in capsule thickness between carriage and clinical genotypes. In conclusion, we found that that the S. suis serotype 9 population in the Netherlands is diverse. A distinct virulence-associated lineage was identified and could be discriminated based on the capsule locus sequence. Whilst the difference in virulence cannot be directly attributed to the DNA sequence, the correlation of capsule locus sequence with virulence could be used in the development of diagnostic tests to identify potential virulent S. suis serotype 9 in pigs.

Older adults’ active involvement in an undergraduate program in gerontology: Motives and meaning
Sliepenbeek, Marjan ; Smits, Carolien ; Spelt, Elisabeth J.H. ; Jukema, Jan S. - \ 2019
Gerontology and Geriatrics Education (2019). - ISSN 0270-1960
cocreation - Gerontological competences - older adults - undergraduate education - volunteers

Two Dutch undergraduate programs in applied gerontology have teamed up with older volunteers to educate students in collaborating with older adults in the field of age-friendly service development. The research question of this study was: What are the motives and meanings of the older volunteers concerning their participation in an undergraduate program? An explorative descriptive qualitative design was used to study the motives and meanings of the older volunteers through semi-structured interviews (n = 11) and a focus group interview (n = 4). Two themes and nine categories emerged: (1) Personal norms and values (categories: responsible life attitude, contribution, self-determination), (2) Personal gain (categories: intergenerational education, personal development, staying healthy, pleasure, feeling appreciated, feeling connected). Personal norms and values and personal gains are meaningful to older volunteers in applied gerontology education. Universities should respect these when designing measures for improving participation methods.

Successional Dynamics in the Gut Microbiome Determine the Success of Clostridium difficile Infection in Adult Pig Models
Jurburg, Stephanie D. ; Cornelissen, Jan J.B.W.J. ; Boer, Paulo de; Smits, Mari A. ; Rebel, Johanna M.J. - \ 2019
Frontiers in Cellular and Infection Microbiology 9 (2019). - ISSN 2235-2988 - 11 p.
animal models - bacteria - Clostridium difficile - microbiome - pig

Clostridium difficile infections (CDI) are a major cause of antibiotic-associated diarrhea. It is hypothesized that CDI develops due to the antibiotic-induced disruption of the intestinal microbial community structure, which allows C. difficile to flourish. Here, we pre-treated weaned pigs with the antibiotics Clindamycin or Ciprofloxacin for 1 day, and subsequently inoculated them with a human and pig enteropathogenic C. difficile strain 078 spores. Body temperature, clinical signs of disease, and the fecal microbiome were monitored daily for 15 days. Clindamycin had a stronger effect on the pigs than Ciprofloxacin, resulting in drastic shifts in the fecal microbiome, decreases in microbial diversity and significant increases in body temperature, even in the absence of C. difficile. Fecal shedding of C. difficile was detectable for 3 and 9 days in Ciprofloxacin and Clindamycin treated pigs inoculated with C. difficile, respectively, and in both cases decreased cell proliferation rates were detected in colon tissue. The timing of C. difficile shedding coincided with the decrease in a large cluster of Firmicutes following Clindamycin treatment, a pattern which was also independent of C. difficile inoculation. The observed community patterns suggest that successional dynamics following antibiotic treatment facilitate C. difficile establishment. The similarities between the microbiome responses observed in our study and those previously reported in CDI-infected humans further support the utility of adult pigs as models for the study of CDI.

The social license to operate of oil and gas development in Greenland
Smits, Coco C.A. - \ 2019
Wageningen University. Promotor(en): J.P.M. van Tatenhove, co-promotor(en): J. van Leeuwen. - Wageningen : Wageningen University - ISBN 9789463950459 - 221
Kun je je alvast wapenen tegen verkoudheid en griep?
Wichers, Harry - \ 2019
Circulaire economie en hergebruik van grondstoffen – de casus fosfaat
Kistenkas, F.H. ; Smits, M.J.W. - \ 2019
Landwerk 2019 (2019)3. - ISSN 1567-1844 - p. 18 - 22.
Akkermansia muciniphila Exerts Lipid-Lowering and Immunomodulatory Effects without Affecting Neointima Formation in Hyperlipidemic APOE*3-Leiden.CETP Mice
Katiraei, Saeed ; Vries, Margreet R. de; Costain, Alice H. ; Thiem, Kathrin ; Hoving, Lisa R. ; Diepen, Janna A. van; Smits, Hermelijn H. ; Bouter, Kristien E. ; Rensen, Patrick C.N. ; Quax, Paul H.A. ; Nieuwdorp, Max ; Netea, Mihai G. ; Vos, Willem M. de; Cani, Patrice D. ; Belzer, Clara ; Dijk, Ko Willems van; Berbée, Jimmy F.P. ; Harmelen, Vanessa van - \ 2019
Molecular Nutrition & Food Research (2019). - ISSN 1613-4125
Akkermansia muciniphila - atherosclerosis - immunity - lipid metabolism - mesenteric lymph nodes

Scope: Akkermansia muciniphila (A. muciniphila) is an intestinal commensal with anti-inflammatory properties both in the intestine and other organs. The aim is to investigate the effects of oral administration of A. muciniphila on lipid metabolism, immunity, and cuff-induced neointima formation in hyperlipidemic APOE*3-Leiden (E3L).CETP mice. Methods and results: Hyperlipidemic male E3L.CETP mice are daily treated with 2 × 108 CFU A. muciniphila by oral gavage for 4 weeks and the effects are determined on plasma lipid levels, immune parameters, and cuff-induced neointima formation and composition. A. muciniphila administration lowers body weight and plasma total cholesterol and triglycerides levels. A. muciniphila influences the immune cell composition in mesenteric lymph nodes, as evident from an increased total B cell population, while reducing the total T cell and neutrophil populations. Importantly, A. muciniphila reduces the expression of the activation markers MHCII on dendritic cells and CD86 on B cells. A. muciniphila also increases whole blood ex vivo lipopolysaccharide-stimulated IL-10 release. Finally, although treatment with A. muciniphila improves lipid metabolism and immunity, it does not affect neointima formation or composition. Conclusions: Four weeks of treatment with A. muciniphila exerts lipid-lowering and immunomodulatory effects, which are insufficient to inhibit neointima formation in hyperlipidemic E3L.CETP mice.

Experiences and views of older people on their participation in a nurse-led health promotion intervention: “community health consultation offices for seniors”
Marcus-Varwijk, Anne Esther ; Madjdian, Dónya S. ; Vet, Emely de; Mensen, Monique W.M. ; Visscher, Tommy L.S. ; Ranchor, Adelita V. ; Slaets, Joris P.J. ; Smits, Carolien H.M. - \ 2019
PLoS ONE 14 (2019)5. - ISSN 1932-6203

The growing number of community-dwelling older adults and the increased risks of adverse health events that accompany ageing, call for health promotion interventions. Nurses often lead these interventions. The views and experiences of older adults participating in these interventions have rarely been studied. To understand the views of targeted older adults, qualitative studies are essential. The aim of this study was to investigate the views and experiences of older adults on their participation in a nurse-led intervention, taking into account their views on healthy aging. Methods In a qualitative study, nineteen Dutch older adults aged 62 to 92 years participated in semi-structured interviews. These were transcribed verbatim and coded with the Qualitative Data Analysis Miner software program. The Qualitative Analysis Guide of Leuven was used for data analysis. Results Based on the analysis of the interviews, the following main themes emerged from the data reflecting the experiences of the participants: 1) awareness of aging, 2) experienced interaction with the nurse, and 3) perception of the consultations as a check-up and/or personal support. Conclusions This study underscores the importance of nurse-led interventions that match older adults’ personal views concerning healthy living, and their views and experiences concerning these interventions. Older adults’ holistic views of healthy living were not always assessed and valued by the nurses. Also, our study shows a wide variety of expectations, views and experiences among the participating older adults. This implies that health professionals should adjust their working and communication methods to the older adult’s views on life.

Multimodal Tracking of Controlled Staphylococcus aureus Infections in Mice
Welling, Mick M. ; Korne, Clarize M. De; Spa, Silvia J. ; Willigen, Danny M. Van; Hensbergen, Albertus W. ; Bunschoten, Anton ; Duszenko, Nikolas ; Smits, Wiep Klaas ; Roestenberg, Meta ; Leeuwen, Fijs W.B. Van - \ 2019
Bmc Infectious Diseases 5 (2019)7. - ISSN 1471-2334 - p. 1160 - 1168.
bacterial infection - cell-tracking - fluorescence - multimodal - SPECT - ubiquicidin

There is a need to develop diagnostic and analytical tools that allow noninvasive monitoring of bacterial growth and dissemination in vivo. For such cell-tracking studies to hold translational value to controlled human infections, in which volunteers are experimentally colonized, they should not require genetic modification, and they should allow tracking over a number of replication cycles. To gauge if an antimicrobial peptide tracer, 99m Tc-UBI 29-41 -Cy5, which contains both a fluorescent and a radioactive moiety, could be used for such in vivo bacterial tracking, we performed longitudinal imaging of a thigh-muscle infection with 99m Tc-UBI 29-41 -Cy5-labeled Staphylococcus aureus. Mice were imaged using SPECT and fluorescence-imaging modalities at various intervals during a 28 h period. Biodistribution analyses were performed to quantitate radioactivity in the abscess and other tissues. SPECT and fluorescence imaging in mice showed clear retention of the 99m Tc-UBI 29-41 -Cy5-labeled bacteria following inoculation in the thigh muscle. Despite bacterial replication, the signal intensity in the abscess only modestly decreased within a 28 h period: 52% of the total injected radioactivity per gram of tissue (%ID/g) at 4 h postinfection (pi) versus 44%ID/g at 28 h pi (15% decrease). After inoculation, a portion of the bacteria disseminated from the abscess, and S. aureus cultures were obtained from radioactive urine samples. Bacterial staining with 99m Tc-UBI 29-41 -Cy5 allowed noninvasive bacterial-cell tracking during a 28 h period. Given the versatility of the presented bacterial-tracking method, we believe that this concept could pave the way for precise imaging capabilities during controlled-human-infection studies.

De betekenis van mestverwerking in een circulaire economie
Woltjer, Geert ; Smits, Marie-José - \ 2019
Wageningen : Wageningen Economic Research (Wageningen Economic Research nota 2019-029) - 23
What is the role of manure processing in the transition to a circular economy? To this end, it is first of all important to get a clear picture of what manure processing is and how (manure) policy influences this. Current manure processing fits within a system that is primarily focused on solving current problems. However, the question is whether there is a role for manure processing if the transition to a circular economy is more advanced and, if so, what that role is.
Fluorescent imaging of bacterial infections and recent advances made with multimodal radiopharmaceuticals
Welling, Mick M. ; Hensbergen, Albertus W. ; Bunschoten, Anton ; Velders, Aldrik H. ; Scheper, Henk ; Smits, Wiep Klaas ; Roestenberg, Meta ; Leeuwen, Fijs W.B. van - \ 2019
Clinical and Translational Imaging 7 (2019)2. - ISSN 2281-5872 - p. 125 - 138.
Bacterial infection - Fluorescence imaging - Infectious diseases - Molecular imaging - Radioactivity

Background: Today, both radioactive SPECT and PET imaging radiopharmaceuticals are used for clinical diagnosis of bacterial infections. Due to the possible applications in image-guided surgery, fluorescent imaging of infections has gained interest. We here present the highlights and recent developments in the use of fluorescence imaging for bacterial infections. In this overview, we also include the latest developments in multimodal bacterial imaging strategies that combine radioactive and fluorescent imaging. Based on this literature, we present our future perspectives for the field including the translational potential. Methods: In the current review, we complement earlier reports with the most recent fluorescent and multimodal radiopharmaceuticals for bacterial infection imaging. Where possible, in this review, the chemical structure of the compounds and clinical images were shown. Results: A total of 35 out of 77 original articles on pre-clinical and clinical imaging of bacterial infections with fluorescent tracers and multimodality radiopharmaceuticals were included for reviewing. Conclusion: In our view, the highest translational potential lies with compounds that are based on targeting vectors that are specific for bacteria: e.g., fluorescently labelled UBI 29–41 , polymyxin B, vancomycin, ZnDPA and a M. tuberculosis-specific β-lactamase-cleavable linker CNIP800. Multimodal concepts using dually labelled UBI 29–41 , vancomycin, and ZnDPA help connect optical imaging to the more traditional use of radiopharmaceuticals in infectious diseases. Multimodal bacterial imaging is a promising strategy not only to diagnose bacterial infections but also to evaluate the effectivity of surgical treatment for infections.

Natuurinclusieve landbouw: van niches naar mainstream (fase 1)
Smits, Marie-José ; Polman, Nico ; Michels, Rolf ; Migchels, Gerard ; Schrijver, Raymond ; Sukkel, Wijnand ; Visser, Andries ; Vogelzang, Theo ; Kistenkas, Fred - \ 2019
Wageningen : Wageningen Economic Research (Wageningen Economic Research nota 2019-033) - 31
In deze studie wordt bekeken hoe natuurinclusieve landbouw op de middellange termijn kan uitgroeien van een niche naar de meest gangbare wijze van productie. Centraal staan de vragen: •Welke verdienmodellen zijn er denkbaar om opschaling van natuurinclusieve landbouw naar mainstream financieel mogelijk te maken?•Welk aandachtspunten zijn van belang om de transitie te faciliteren zodat op de middellange termijn natuurinclusieve landbouw kan uitgroeien van niche naar mainstream?
Cold chains in Hanoi and Bangkok: Changing systems of provision and practice
Rinkinen, Jenny ; Shove, E. ; Smits, M. - \ 2019
Journal of Consumer Culture 19 (2019)3. - ISSN 1469-5405 - p. 379 - 397.
social practice - systems of provision - urbanisation - refrigeration - food
We know that patterns of domestic consumption are situated within broader systems of provision and that home appliances like the fridge freezer bridge between practices of cooking, shopping and eating, on one hand, and increasingly global systems of food production, distribution and diet on the other. In analysing the uses of fridge freezers in Hanoi and Bangkok as expressions, in microcosm, of complex and evolving processes of urbanisation and food provisioning, this article provides new insight into how specific configurations, dependencies and patterns of consumption take hold and how they vary and change. Our analysis of systems and practices in flux has the dual function of showing how household strategies reflect and contribute to more extensive transformations, and of demonstrating how these are shaped by ongoing tensions and relations between new and established forms of urban food supply and associated concepts of freshness and safety. The result is a subtle account of the multiple routes through which consumer ‘needs’ evolve.
Prevalence of tick-borne viruses in Ixodes ricinus assessed by high-throughput real-time PCR
Gondard, Mathilde ; Michelet, Lorraine ; Nisavanh, Athinna ; Devillers, Elodie ; Delannoy, Sabine ; Fach, Patrick ; Aspan, Anna ; Ullman, Karin ; Chirico, Jan ; Hoffmann, Bernd ; Wal, Fimme Jan van der; Koeijer, Aline de; Solt-Smits, Conny van; Jahfari, Seta ; Sprong, Hein ; Mansfield, Karen L. ; Fooks, Anthony R. ; Klitgaard, Kirstine ; Bødker, Rene ; Moutailler, Sara - \ 2018
Pathogens and Disease 76 (2018)8. - ISSN 2049-632X
Europe - microfluidic analysis - molecular epidemiology - surveillance - tick borne viruses

Ticks are one of the principal arthropod vectors of human and animal infectious diseases. Whereas the prevalence of tick-borne encephalitis virus in ticks in Europe is well studied, there is less information available on the prevalence of the other tick-borne viruses (TBVs) existing worldwide. The aim of this study was to improve the epidemiological survey tools of TBVs by the development of an efficient high-throughput test to screen a wide range of viruses in ticks. In this study, we developed a new high-throughput virus-detection assay based on parallel real-time PCRs on a microfluidic system, and used it to perform a large scale epidemiological survey screening for the presence of 21 TBVs in 18 135 nymphs of Ixodes ricinus collected from five European countries. This extensive investigation has (i) evaluated the prevalence of four viruses present in the collected ticks, (ii) allowed the identification of viruses in regions where they were previously undetected. In conclusion, we have demonstrated the capabilities of this new screening method that allows the detection of numerous TBVs in a large number of ticks. This tool represents a powerful and rapid system for TBVs surveillance in Europe and could be easily customized to assess viral emergence.

Insights from the Circular Impacts case studies : Work package 4
Woltjer, G.B. ; Smits, M.J.W. ; Duin, Laurens ; Best, Aaron ; Hasenheit, Marius ; Drabik, Eleanor ; Rizos, Vasileios - \ 2018
EU - 61 p.
Phosphorus Recycling from manure – A Case Study on the Circular Economy : Work package 4
Smits, M.J.W. ; Woltjer, G.B. ; Luesink, H.H. ; Beekman, V. ; Koeijer, T.J. de; Daatselaar, C.H.G. ; Duin, Laurens - \ 2018
EU - 61 p.
Innovatieproject Hondsbossche Duinen
Ouwerkerk, Sonja ; Bodde, W. ; Smit, Marije ; Verheijen, Anne ; Leenders, Jakolien ; Wegman, Carolien ; Lagendijk, Georgette ; Scholl, Michaela ; Kuiters, A.T. ; Smits, N.A.C. ; Vries, Daisy de; Huiskes, H.P.J. ; Kramer, Henk ; Valk, Bert van der; IJff, Stéphanie - \ 2018
Ecoshape - 101 p.
Simulations of osmotic events in vitrification of equine oocytes and porcine embryos
Woelders, H. ; Guignot, Florence ; Oritiz-Escribano, Nerea ; Soom, A. van; Smits, Katrien - \ 2018
Holstein Friesian mid-lactation Milk Polar Metabolite Composition in relation to Dietary Fat Composition and DGAT1 Genotype
Pas, M.F.W. te; Vervoort, J. ; Kruijt, L. ; Calus, M.P.L. ; Smits, M. - \ 2018
BioRxiv
Background: The metabolite composition of cow milk is dependent on a large variety of animal associated factors including diet, genotype and gut microbiome composition. The objective of this study was to investigate changes in cow milk polar metabolite composition resulting from dietary and DGAT1 (Diacylglycerol O-acyltransferase 1) genotype perturbations. Methods and Results: Cows were fed a standard diet and a diet supplemented with (poly)unsaturated fatty acids (experimental diet) for ten weeks. Metabolite profiles were determined using 1H NMR (1-Hydrogen Nuclear magnetic resonance) technology. The results showed that the diet affected the polar metabolite composition of milk via the metabolism of the cow and via the metabolism of the gut and rumen microbiota. The experimental diet reduced the metabolic rate, especially the energy metabolism and the amino-sugar and amino acid metabolism, of the cows. Conclusion: Our results suggests the DGAT1 genotype affects both the diet related polar metabolite metabolism of the cow as well as that of the rumen microbiota. Milk metabolite levels in animals with more DGAT1 A-alleles were higher than milk metabolite levels in animals with more K-alleles.
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