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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Gut microbiota from infant with cow’s milk allergy promotes clinical and immune features of atopy in a murine model
Mauras, Aurélie ; Wopereis, Harm ; Yeop, Intan ; Esber, Nathalie ; Delannoy, Johanne ; Labellie, Chantal ; Reygner, Julie ; Kapel, Nathalie ; Slump, Rob ; Eijndthoven, Tiemen van; Rutten, Lieke ; Knol, Jan ; Garssen, Johan ; Harthoorn, Lucien F. ; Butel, Marie José ; Bajaj-Elliott, Mona ; Hartog, Anita ; Waligora-Dupriet, Anne Judith - \ 2019
Allergy (2019). - ISSN 0105-4538
Creating a window of opportunity for establishing ecosystem engineers by adding substratum: a case study on mussels
Capelle, Jacob J. ; Leuchter, Lennet ; Wit, Maurice ; Hartog, Eva ; Bouma, Tjeerd J. - \ 2019
Ecosphere 10 (2019)4. - ISSN 2150-8925 - p. e02688 - e02688.
aggregation - Density dependence - dislodgement - disturbance - flume - Mytilus edulis - positive feedback - stable state
Ecosystem engineers typically exert positive feedback on their environment, which enhances their performance. Such positive feedback is lacking in the establishment phase, when densities are too low and/or patches are too small. There is a strong need to unravel the mechanisms for overcoming the resulting
establishment thresholds, both for ecological restoration purposes and to be able to use their services. In the present study, we question whether providing a transient substratum can be used as tool to overcome establishment thresholds, by creating a window of opportunity for initial settlement, using mussels (Mytilus edulis) as a model system. Combining field and flume experiments, we study how biogenic substratum enrichment in the form of a shell layer on a soft mudflat affects the critical dislodgement thresholds and, thus, the chances of mussel establishment at different mussel densities and aggregation states. Flume results showed that the presence of a shell layer reduced dislodgement of mussel patches in low-energy environments but was conditional for establishment in high-energy environments. That is, in high-energy environments with shells, aggregation into clumps enhanced dislodgement, while dislodgement was reduced with increasing overall mussel biomass and overall mussel patch weight. Without shells, dislodgement was always 100%. These findings agreed with our field studies, which showed that coarse shell material reduced mussel losses (by a factor of 3), reduced aggregation (by a factor of 2.4), and increased attachment strength (by a factor of 2.4). Overall, our results show that the local presence of biogenic substratum increases the
chance of mussel establishment by enhancing the critical hydrodynamic dislodgement threshold. Thus, the local addition of a biogenic substratum may create a window of opportunity to initiate settlement in more
dynamic environments, to shift at a local scale from a bare mudflat state into an established biogenic reef state. Our findings have clear implications for how to approach restoration and management of ecosystem engineers dominated systems. For instance, when positive feedback of ecosystem engineers is lacking, (1) the transient offering of suitable settling substratum may be a necessary step to overcome establishment thresholds, and (2) this becomes increasingly important with increasing abiotic stress.
Dietary supplementation of 11 different plant extracts on the antioxidant capacity of blood and selected tissues in lightweight lambs
Leal, Leonel N. ; Jordán, María J. ; Bello, José M. ; Otal, Julio ; Hartog, Leo A. den; Hendriks, Wouter H. ; Martín-Tereso, Javier - \ 2019
Journal of the Science of Food and Agriculture 99 (2019)9. - ISSN 0022-5142 - p. 4296 - 4303.
kidney - lambs - liver - muscle - plant extracts - plasma

BACKGROUND: Due to the growing public concern regarding the addition of chemical antioxidants to foods, focus has shifted towards natural alternatives. Because of their antioxidant potential, culinary herbs and spices have long been used to extend the shelf-life of foods. However, a better understanding of the fate of these products following intake is required to assess their use in lamb diets. RESULTS: Two hundred and eighty-eight Rasa Aragonesa male lambs (70 days old) were supplemented (5.0 g kg −1 compound feed) with bay, marjoram, oregano, rosemary, thyme, turmeric, cumin, caraway, dill, cinnamon and nutmeg extracts for 14 days before slaughter. Dietary supplementation with plant extracts had no effect on intake, growth performance or antioxidant activity in blood (TEAC values). In muscle, nutmeg supplementation increased (P < 0.05) the radical-scavenging capacity (TEAC), whereas a decrease in the radical-scavenging capacity was found for lambs supplemented with oregano, dill, cinnamon and nutmeg (ORAC values). In liver, nutmeg supplementation increased (P < 0.05) the antioxidant capacity (TEAC), whereas bay (ORAC), turmeric, cinnamon and nutmeg (DPPH values) decreased (P < 0.05) the radical-scavenging capacity of the tissue. In kidney, a lower (P < 0.05) radical-scavenging capacity (TEAC values) was found in lambs supplemented with oregano, cumin and caraway, whereas, turmeric, cumin, caraway, cinnamon and nutmeg increased (P < 0.05) the antioxidant capacity (ORAC values) in kidney. CONCLUSION: Supplementation of lamb diets with plant extracts affected radical-scavenging activity in muscle, liver and kidney. However, due to the divergent results of the different assays for the same tissue, it is not advisable to discriminate plant extracts using this approach.

Data from: Comparative genomics of the nonlegume Parasponia reveals insights into evolution of nitrogen-fixing rhizobium symbioses
Velzen, R. van; Holmer, R. ; Bu, F. ; Rutten, L.J.J. ; Zeijl, A.L. van; Liu, W. ; Santuari, L. ; Cao, Q. ; Sharma, Trupti ; Shen, D. ; Roswanjaya, Yuda ; Wardhani, T. ; Seifi Kalhor, M. ; Jansen, Joelle ; Hoogen, D.J. van den; Gungor, Berivan ; Hartog, M.V. ; Hontelez, Jan ; Verver, J.W.G. ; Yang, Wei-Cai ; Schijlen, E.G.W.M. ; Repin, Rimi ; Schilthuizen, M. ; Schranz, M.E. ; Heidstra, R. ; Miyata, Kana ; Fedorova, E. ; Kohlen, W. ; Bisseling, A.H.J. ; Smit, S. ; Geurts, R. - \ 2018
comparative genomics - copy number variation - evolution - nitrogen fixation - symbiosis - Parasponia andersonii - Parasponia rigada - Parasponia rugosa - Trema levigata - Trema orientalis - Trema tomentosa
Nodules harboring nitrogen-fixing rhizobia are a well-known trait of legumes, but nodules also occur in other plant lineages, with rhizobia or the actinomycete Frankia as microsymbiont. It is generally assumed that nodulation evolved independently multiple times. However, molecular-genetic support for this hypothesis is lacking, as the genetic changes underlying nodule evolution remain elusive. We conducted genetic and comparative genomics studies by using Parasponia species (Cannabaceae), the only nonlegumes that can establish nitrogen-fixing nodules with rhizobium. Intergeneric crosses between Parasponia andersonii and its nonnodulating relative Trema tomentosa demonstrated that nodule organogenesis, but not intracellular infection, is a dominant genetic trait. Comparative transcriptomics of P. andersonii and the legume Medicago truncatula revealed utilization of at least 290 orthologous symbiosis genes in nodules. Among these are key genes that, in legumes, are essential for nodulation, including NODULE INCEPTION (NIN) and RHIZOBIUM-DIRECTED POLAR GROWTH (RPG). Comparative analysis of genomes from three Parasponia species and related nonnodulating plant species show evidence of parallel loss in nonnodulating species of putative orthologs of NIN, RPG, and NOD FACTOR PERCEPTION. Parallel loss of these symbiosis genes indicates that these nonnodulating lineages lost the potential to nodulate. Taken together, our results challenge the view that nodulation evolved in parallel and raises the possibility that nodulation originated ∼100 Mya in a common ancestor of all nodulating plant species, but was subsequently lost in many descendant lineages. This will have profound implications for translational approaches aimed at engineering nitrogen-fixing nodules in crop plants
Innovations for sustainable poultry nutrition
Hartog, L.A. den - \ 2018
Nutritional strategies to reduce the need for antibiotics in animals
Hartog, L.A. den - \ 2018
Innovations for sustainable animal nutrition
Hartog, L.A. den - \ 2018
Bioavailability of α-tocopherol stereoisomers in lambs depends on dietary doses of all-rac- or RRR-α-tocopheryl acetate
Neto Leal, Leonel ; Jensen, S.K. ; Bello, J.M. ; Hartog, L.A. den; Hendriks, W.H. ; Martín-Tereso, Javier - \ 2018
Animal (2018). - ISSN 1751-7311 - 9 p.
When supplementing lamb diets with vitamin E, an equivalence factor of 1.36 is used to discriminate between RRR-α-tocopheryl acetate and all-rac-α tocopheryl acetate. However, more recent studies suggest a need for new equivalence factors for livestock animals. The current study aimed to determine the effect of RRR- and all-rac-α-tocopheryl acetate supplementation on α-tocopherol deposition in lamb tissues. A total of 108 Rasa Aragonesa breed lambs were fed increasing amounts of all-rac-α-tocopheryl acetate (0.25, 0.5, 1.0 and 2.0 g/kg compound feed) or RRR-α-tocopheryl acetate (0.125, 0.25, 0.5 and 1.0 g/kg compound feed) by adding them to a basal diet that contained 0.025 g/kg feed of all-rac-α-tocopheryl acetate as part of the standard vitamin and mineral mixture. The diets were fed for the last 14 days before slaughtering at 25.8 ± 1.67 kg BW. Within 20 min after slaughter samples of muscle, heart, liver, brain and spleen were frozen at −20°C until α-tocopherol analysis. Increased supplementation of either vitamin E sources led to a significant increase ( P<0.001) in α-tocopherol concentration in all tissues studied. The tissue with the highest α-tocopherol concentration was the liver followed by spleen, heart and muscle. At similar supplementation levels (0.25, 0.50 and 1.0 g/kg compound feed), α-tocopherol content in the selected tissues was not affected by α-tocopherol source. However, the ratios between RRR- and all-rac α-tocopheryl acetate increased with the increasing α-tocopherol supplementation (at 0.25 and 1.0 g/kg compound feed), from 1.06 to 1.16 in muscle, 1.07 to 1.15 in heart, 0.91 to 0.94 in liver and 0.98 to 1.10 in spleen. The highest relative proportion of Ʃ2S (sum of SSS-, SSR-, SRS- and SRR-α tocopherol)-configured stereoisomers was found in the liver of lambs supplemented with all-rac-α-tocopheryl acetate accounting for up to 35 to 39% of the total α-tocopherol retained, whereas the proportion of Ʃ2S-configured stereoisomers in the other tissues accounted for <14%. Increasing all-rac-α-tocopheryl acetate supplementation was also found to affect the 2R-configured stereoisomer profile in muscle, heart and spleen with increasing proportions of RRS-, RSR- and RSS- at the cost of RRR-α-tocopherol. In all tissues, the relative proportion of all non-RRR-stereoisomers in lambs receiving RRR-α-tocopheryl acetate was lower than RRR-α-tocopherol. These results confirm that the relative bioavailability of RRR- and all-rac-α-tocopheryl acetate is dose- and tissue-dependent and that a single ratio to discriminate the two sources cannot be used.
LED in rozen het moet beter!
Gelder, Arie de; Burg, Rick van der; Hartog, Ben - \ 2018
Bleiswijk : Wageningen University & Research, BU Glastuinbouw (Rapport Wageningen Plant Research WPR-819) - 34
Red Naomi! roses were grown under full LED and cooling in the summer of 2017 in a similar way as in 2016 with good results. At the end of October 2017, LEDs with an adapted spectrum were placed in 1/3 of the compartment. The quality problem again occurred under the red /blue spectrum, but in a lesser degree. Equal input of heat via the OPACs and pipe rail system had a favourable effect on the temperature distribution in the crop and thus on the development of the stems. Also crop treatments such as cutting strategy and bending have contributed to a better quality. The adjusted spectrum gave slightly larger buds, larger leaves and less thorns. That the “syndrome” was clearly less present under the adjusted spectrum has been confirmed by measures of flower properties, such as bud size, leaf size and number of thorns. In order to achieve sufficient dynamics in air humidity within a 24-hour period, the lightemission screen could not be completely closed. The energy target of 25% savings is realized when compared to a situation where the SON-T would be used as the LED for an equal number of hours. All the heat needed for cultivation, even when using LED lighting, can be collected in the summer by cooling the greenhouse and storage in an aquifer. The shelf life of roses grown under LED was comparable to that of a practical company. The research was conducted by Wageningen University & Research and Delphy in the context of Kas als Energiebron.
Integrating breeding, diet, additives and hygiene key to on-farm antibiotic reduction, says Professor den Hartog
Hartog, Leonard den - \ 2018
Wie wirkt sich die Tierernährung auf unser Klima aus?
Hartog, Leonard den - \ 2018
Innovations for sustainable poultry nutrition
Hartog, Leonard den - \ 2018
Innovative feeding regimes & advice to support gut health and animal welfare as part of animal health management plan at farm level
Hartog, Leonard den - \ 2018
Nutritional strategies to reduce the need for antibiotics in animals
Hartog, Leonard den - \ 2018
Innovations in sustainable animal nutrition
Hartog, Leonard den - \ 2018
What to expect from future science and technology to improve efficiency?
Hartog, Leonard den - \ 2018
Lipase diffusion in oil-filled, alginate micro- and macrobeads
Leusden, P. van; Hartog, G.J.M. den; Bast, A. ; Postema, M. ; Linden, E. van der; Sagis, L.M.C. - \ 2018
Food Hydrocolloids 85 (2018). - ISSN 0268-005X - p. 242 - 247.
Oil digestion - Microbeads - Encapsulation - Diffusion - Maxwell-Cattaneo equation
Triglycerides, which are broken down in the lower part of the intestinal tract, give a stronger ileal brake feedback, resulting in a feeling of satiety and causing people to eat less. The digestion of triglycerides into fatty acids by lipase in the intestine can be delayed by encapsulating oil droplets. In this study the release of fatty acids and oil droplet breakdown in a simulated intestinal system was investigated, for oil droplets encapsulated in alginate micro- (10.7 μm) and macrobeads (1.77 mm). It was found that fatty acid release rate was greatly decreased by encapsulating the oil droplets into an alginate matrix compared to loose droplets. Microscopic imaging of the breakdown of the oil droplets showed a sharp front moving from the bead interface to the centre of the bead, and the change in position of the front scaled linear with time. The motion of the front is well described by combining the mass balance for lipase with a Maxwell-Cattaneo type equation, for the mass flux vector. The front in microbeads seemed to move slightly slower (0.15 (±0.04) μm per minute) than for the macrobeads (0.20 (±0.02) μm per minute). The release of free fatty acids in microbeads was faster than in macrobeads, despite the slower front movement, because of the larger amount of surface area available.
Effects of structure on hydrogel microbead function
Leusden, Pauline van - \ 2018
Wageningen University. Promotor(en): Erik van der Linden; Leonard Sagis, co-promotor(en): M.A.B. Postema; G.J.M. Hartog. - Wageningen : Wageningen University - ISBN 9789463438568 - 136
Comparative genomics of the nonlegume Parasponia reveals insights into evolution of nitrogen-fixing rhizobium symbioses
Velzen, R. van; Holmer, R. ; Bu, F. ; Rutten, L.J.J. ; Zeijl, A.L. van; Liu, W. ; Santuari, L. ; Cao, Q. ; Sharma, Trupti ; Shen, Defeng ; Purwana Roswanjaya, Yuda ; Wardhani, T. ; Seifi Kalhor, M. ; Jansen, Joelle ; Hoogen, D.J. van den; Güngör, Berivan ; Hartog, M.V. ; Hontelez, J. ; Verver, Jan ; Yang, Wei-Cai ; Schijlen, E.G.W.M. ; Repin, Rimi ; Schilthuizen, M. ; Schranz, M.E. ; Heidstra, R. ; Miyata, Kana ; Fedorova, E. ; Kohlen, W. ; Bisseling, A.H.J. ; Smit, S. ; Geurts, R. - \ 2018
Proceedings of the National Academy of Sciences of the United States of America 115 (2018)20. - ISSN 0027-8424 - p. E4700 - E4709.
Nodules harboring nitrogen-fixing rhizobia are a well-known trait of legumes, but nodules also occur in other plant lineages, with rhizobia or the actinomycete Frankia as microsymbiont. It is generally assumed that nodulation evolved independently multiple times. However, molecular-genetic support for this hypothesis is lacking, as the genetic changes underlying nodule evolution remain elusive. We conducted genetic and comparative genomics studies by using Parasponia species (Cannabaceae), the only nonlegumes that can establish nitrogen-fixing nodules with rhizobium. Intergeneric crosses between Parasponia andersonii and its nonnodulating relative Trema tomentosa demonstrated that nodule organogenesis, but not intracellular infection, is a dominant genetic trait. Comparative transcriptomics of P. andersonii and the legume Medicago truncatula revealed utilization of at least 290 orthologous symbiosis genes in nodules. Among these are key genes that, in legumes, are essential for nodulation, including NODULE INCEPTION (NIN) and RHIZOBIUM-DIRECTED POLAR GROWTH (RPG). Comparative analysis of genomes from three Parasponia species and related nonnodulating plant species show evidence of parallel loss in nonnodulating species of putative orthologs of NIN, RPG, and NOD FACTOR PERCEPTION. Parallel loss of these symbiosis genes indicates that these nonnodulating lineages lost the potential to nodulate. Taken together, our results challenge the view that nodulation evolved in parallel and raises the possibility that nodulation originated ∼100 Mya in a common ancestor of all nodulating plant species, but was subsequently lost in many descendant lineages. This will have profound implications for translational approaches aimed at engineering nitrogen-fixing nodules in crop plants.
CRISPR/cas9-mediated mutagenesis of four putative symbiosis genes of the tropical tree parasponia andersonii reveals novel phenotypes
Zeijl, Arjan Van; Wardhani, Titis A.K. ; Seifi Kalhor, Maryam ; Rutten, Luuk ; Bu, Fengjiao ; Hartog, Marijke ; Linders, Sidney ; Fedorova, Elena E. ; Bisseling, Ton ; Kohlen, Wouter ; Geurts, Rene - \ 2018
Frontiers in Plant Science 9 (2018). - ISSN 1664-462X
CRISPR/Cas9 - Nodule - Parasponia andersonii - Rhizobium - Stable transformation - Symbiosis
Parasponia represents five fast-growing tropical tree species in the Cannabaceae and is the only plant lineage besides legumes that can establish nitrogen-fixing nodules with rhizobium. Comparative analyses between legumes and Parasponia allows identification of conserved genetic networks controlling this symbiosis. However, such studies are hampered due to the absence of powerful reverse genetic tools for Parasponia. Here, we present a fast and efficient protocol for Agrobacterium tumefaciens-mediated transformation and CRISPR/Cas9 mutagenesis of Parasponia andersonii. Using this protocol, knockout mutants are obtained within 3 months. Due to efficient micro-propagation, bi-allelic mutants can be studied in the T0 generation, allowing phenotypic evaluation within 6 months after transformation. We mutated four genes – PanHK4, PanEIN2, PanNSP1, and PanNSP2 – that control cytokinin, ethylene, or strigolactone hormonal networks and that in legumes commit essential symbiotic functions. Knockout mutants in Panhk4 and Panein2 displayed developmental phenotypes, namely reduced procambium activity in Panhk4 and disturbed sex differentiation in Panein2 mutants. The symbiotic phenotypes of Panhk4 and Panein2 mutant lines differ from those in legumes. In contrast, PanNSP1 and PanNSP2 are essential for nodule formation, a phenotype similar as reported for legumes. This indicates a conserved role for these GRAS-type transcriptional regulators in rhizobium symbiosis, illustrating the value of Parasponia trees as a research model for reverse genetic studies.
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