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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Ancient pigs reveal a near-complete genomic turnover following their introduction to Europe
Frantz, Laurent A.F. ; Haile, James ; Lin, Audrey T. ; Scheu, Amelie ; Geörg, Christina ; Benecke, Norbert ; Alexander, Michelle ; Linderholm, Anna ; Mullin, Victoria E. ; Daly, Kevin G. ; Battista, Vincent M. ; Price, Max ; Gron, Kurt J. ; Alexandri, Panoraia ; Arbogast, Rose Marie ; Arbuckle, Benjamin ; Bǎlǎşescu, Adrian ; Barnett, Ross ; Bartosiewicz, László ; Baryshnikov, Gennady ; Bonsall, Clive ; Borić, Dušan ; Boroneanţ, Adina ; Bulatović, Jelena ; Çakirlar, Canan ; Carretero, José Miguel ; Chapman, John ; Church, Mike ; Crooijmans, Richard ; Cupere, Bea De; Detry, Cleia ; Dimitrijevic, Vesna ; Dumitraşcu, Valentin ; Plessis, Louis Du; Edwards, Ceiridwen J. ; Erek, Cevdet Merih ; Erim-Özdoǧan, Asli ; Ervynck, Anton ; Fulgione, Domenico ; Gligor, Mihai ; Götherström, Anders ; Gourichon, Lionel ; Groenen, Martien A.M. ; Helmer, Daniel ; Hongo, Hitomi ; Horwitz, Liora K. ; Irving-Pease, Evan K. ; Lebrasseur, Ophélie ; Lesur, Joséphine ; Malone, Caroline ; Manaseryan, Ninna ; Marciniak, Arkadiusz ; Martlew, Holley ; Mashkour, Marjan ; Matthews, Roger ; Matuzeviciute, Giedre Motuzaite ; Maziar, Sepideh ; Meijaard, Erik ; McGovern, Tom ; Megens, Hendrik Jan ; Miller, Rebecca ; Mohaseb, Azadeh Fatemeh ; Orschiedt, Jörg ; Orton, David ; Papathanasiou, Anastasia ; Pearson, Mike Parker ; Pinhasi, Ron ; Radmanović, Darko ; Ricaut, François Xavier ; Richards, Mike ; Sabin, Richard ; Sarti, Lucia ; Schier, Wolfram ; Sheikhi, Shiva ; Stephan, Elisabeth ; Stewart, John R. ; Stoddart, Simon ; Tagliacozzo, Antonio ; Tasić, Nenad ; Trantalidou, Katerina ; Tresset, Anne ; Valdiosera, Cristina ; Hurk, Youri Van Den; Poucke, Sophie Van; Vigne, Jean Denis ; Yanevich, Alexander ; Zeeb-Lanz, Andrea ; Triantafyllidis, Alexandros ; Gilbert, M.T.P. ; Schibler, Jörg ; Rowley-Conwy, Peter ; Zeder, Melinda ; Peters, Joris ; Cucchi, Thomas ; Bradley, Daniel G. ; Dobney, Keith ; Burger, Joachim ; Evin, Allowen ; Girdland-Flink, Linus ; Larson, Greger - \ 2019
Proceedings of the National Academy of Sciences of the United States of America 116 (2019)35. - ISSN 0027-8424 - p. 17231 - 17238.
Domestication - Evolution - Gene flow - Neolithic

Archaeological evidence indicates that pig domestication had begun by ∼10,500 y before the present (BP) in the Near East, and mitochondrial DNA (mtDNA) suggests that pigs arrived in Europe alongside farmers ∼8,500 y BP. A few thousand years after the introduction of Near Eastern pigs into Europe, however, their characteristic mtDNA signature disappeared and was replaced by haplotypes associated with European wild boars. This turnover could be accounted for by substantial gene flow from local European wild boars, although it is also possible that European wild boars were domesticated independently without any genetic contribution from the Near East. To test these hypotheses, we obtained mtDNA sequences from 2,099 modern and ancient pig samples and 63 nuclear ancient genomes from Near Eastern and European pigs. Our analyses revealed that European domestic pigs dating from 7,100 to 6,000 y BP possessed both Near Eastern and European nuclear ancestry, while later pigs possessed no more than 4% Near Eastern ancestry, indicating that gene flow from European wild boars resulted in a near-complete disappearance of Near East ancestry. In addition, we demonstrate that a variant at a locus encoding black coat color likely originated in the Near East and persisted in European pigs. Altogether, our results indicate that while pigs were not independently domesticated in Europe, the vast majority of human-mediated selection over the past 5,000 y focused on the genomic fraction derived from the European wild boars, and not on the fraction that was selected by early Neolithic farmers over the first 2,500 y of the domestication process.

Metatranscriptomics reveals mycoviral populations in the ovine rumen
Hitch, Thomas C.A. ; Edwards, Joan E. ; Gilbert, Rosalind A. - \ 2019
FEMS Microbiology Letters 366 (2019)13. - ISSN 0378-1097
fungi - mycobiome - mycovirus - RNA - rumen

The rumen is known to contain DNA-based viruses, although it is not known whether RNA-based viruses that infect fungi (mycoviruses) are also present. Analysis of publicly available rumen metatranscriptome sequence data from sheep rumen samples (n = 20) was used to assess whether RNA-based viruses exist within the ovine rumen. A total of 2466 unique RNA viral contigs were identified that had homology to nine viral families. The Partitiviridae was the most consistently observed mycoviral family. High variation in the abundance of each detected mycovirus suggests that rumen mycoviral populations vary greatly between individual sheep. Functional analysis of the genes within the assembled mycoviral contigs suggests that the mycoviruses detected had simple genomes, often only carrying the machinery required for replication. The fungal population of the ovine rumen was also assessed using metagenomics data from the same samples, and was consistently dominated by the phyla Ascomycota and Basidomycota. The strictly anaerobic phyla Neocallimastigomycota were also present in all samples but at a low abundance. This preliminary investigation has provided clear evidence that mycoviruses with RNA genomes exist in the rumen, with further in-depth studies now required to characterise this mycoviral community and determine its role in the rumen.

A predictive strategy for mapping locations where future MOSSFA events are expected
Murk, A.J. ; Hollander, D.J. ; Chen, S. ; Hu, C. ; Liu, Y. ; Vonk, S.M. ; Schwing, Patrick T. ; Gilbert, S. ; Foekema, E.M. - \ 2019
In: Scenarios and Responses to Future Deep Oil Spills / Murawski, S.A., Ainsworth, C.H., Gilbert, S., Hollander, D.J., Paris, C.B., Schlueter, M., Wetzel, D.L., - p. 355 - 368.
A MOSSFA (marine oil snow sedimentation and flocculent accumulation) event was the reason that substantial amounts of the spilled oil were transported to the seafloor during the Deepwater Horizon (DWH) oil well blowout. The region-wide sinking and flocculent accumulation of marine oil snow on the sediment surface changed redox conditions, slowed down the biodegradation of the oil, and increased the spatial and temporal impacts on the benthic community and habitat suitability. Recent field research has confirmed that, in addition to the DWH MOSSFA event in the northern Gulf of Mexico (nGoM), another extensive MOSSFA event occurred in a biologically sensitive area in the southern Gulf of Mexico (sGoM) during the 1979 - 1980 Ixtoc I oil well blowout. Thus, MOSSFA events are not unexpected and have the potential to not only alter sediment chemical conditions but also to extend, expand, and intensify the ecological impact of an oil spill. Consequently this risk should be taken into consideration when preparing response...
Effect of marine snow on microbial oil degradation
Langenhoff, A.A.M. ; Rahsepar, Shokouh ; Eenennaam, J.S. van; Radović, Jagoš R. ; Oldenburg, Thomas B.P. ; Foekema, E.M. ; Murk, A.J. - \ 2019
In: Deep Oil Spills / Murawski, S.A., Ainsworth, C.H., Gilbert, S., Hollander, D.J., Paris, C.B., Schlueter, M., Wetzel, D.L., - p. 301 - 311.
In the aftermath of an oil spill, a possible response is the addition of chemical dispersants to prevent further spreading of the spilled oil on the ocean surface. The main objective is to enhance the formation of smaller oil droplets by reducing the interfacial tension between oil and water, thus dispersing the oil into the water column. The resulting solubilized oil with microdroplets along with the associated toxic compounds will be swiftly incorporated into the seawater. The formation of smaller oil droplets and the dispersant enhanced solubilized oil will increase its availability for bacteria and thus the biodegradability. Subsequently, the number and activity of oil-degrading bacteria increases, and more oil will be degraded in a shorter period of time (Kessler et al., Science 331:312–315, 2011). However, during the immediate release of the dispersed oil, volatile hydrocarbons including some of the more toxic compounds of benzene, toluene, ethylbenzene, and xylenes (BTEX) can inhibit the oil degradation (Sherry et al., Front Microbiol 5:131, 2014).
Depending on the oceanic conditions, the addition of chemical dispersants can result in excessive formation of marine snow. It has been shown that the application of dispersants during phytoplankton blooms can trigger the formation of marine snow to which the sticky dispersed oil can bind. In the presence of mineral particles, oiled snow complexes are being formed that become negatively buoyant and sink to the ocean floor. As a result, oiled marine snow accumulates on the ocean floor where biodegradation is inhibited due to oxygen depletion.
The abovementioned two mechanisms of inhibition of oil biodegradation upon application of oil spill dispersants will be discussed in this chapter.
Testing the Effect of MOSSFA (Marine Oil Snow Sedimentation and Flocculent Accumulation) Events in Benthic Microcosms
Foekema, E.M. ; Eenennaam, Justine van; Hollander, D.J. ; Langenhoff, A.A.M. ; Oldenburg, Thomas B.P. ; Radović, Jagoš R. ; Rohal, Melissa ; Romero, Isabel C. ; Schwing, Patrick T. ; Murk, A.J. - \ 2019
In: Scenarios and Responses to Future Deep Oil Spills / Murawski, S.A., Ainsworth, C.H., Gilbert, S., Hollander, D.J., Paris, C.B., Schlueter, M., Wetzel, D.L., - p. 288 - 299.
In multispecies experiments performed in microcosms with natural sediment, it was investigated how the presence of marine snow affects the fate and ecological impact of deposited oil residues. The response of different taxonomic groups like nematodes, foraminifera, crustaceans and molluscs onto the presence of marine snow with or without oil was compared with the impact of deposited oil residues without marine snow. Also the effect of the presence of marine snow on oil biodegradation and transfer for oil-derived compounds to selected biota was studied. Although not designed to mimic the specific deep sea conditions in the Gulf of Mexico, the outcome of the experiments gave new insights in how a MOSSFA event can affect the benthic community. In general the experments indicated that at field realistic oil-derived compound concentrations, the adverse impact of the marine snow on the sediment surface has a stronger impact on the benthic ecosystem than...
Living in cold blood: Arcobacter, Campylobacter, and Helicobacter in reptiles
Gilbert, Maarten J. ; Duim, Birgitta ; Zomer, Aldert L. ; Wagenaar, Jaap A. - \ 2019
Frontiers in Microbiology 10 (2019)MAY. - ISSN 1664-302X
Arcobacter - Biodiversity - Campylobacter - Ecology - Epsilonproteobacteria - Evolution - Helicobacter - Reptile

Species of the Epsilonproteobacteria genera Arcobacter, Campylobacter, and Helicobacter are commonly associated with vertebrate hosts and some are considered significant pathogens. Vertebrate-associated Epsilonproteobacteria are often considered to be largely confined to endothermic mammals and birds. Recent studies have shown that ectothermic reptiles display a distinct and largely unique Epsilonproteobacteria community, including taxa which can cause disease in humans. Several Arcobacter taxa are widespread amongst reptiles and often show a broad host range. Reptiles carry a large diversity of unique and novel Helicobacter taxa, which apparently evolved in an ectothermic host. Some species, such as Campylobacter fetus, display a distinct intraspecies host dichotomy, with genetically divergent lineages occurring either in mammals or reptiles. These taxa can provide valuable insights in host adaptation and co-evolution between symbiont and host. Here, we present an overview of the biodiversity, ecology, epidemiology, and evolution of reptile-associated Epsilonproteobacteria from a broader vertebrate host perspective.

Late Quaternary lahars and lava dams: Fluvial responses of the Upper Tana River (Kenya)
Schoorl, J.M. ; Veldkamp, A. ; Claessens, L. ; Wijbrans, J.R. ; Olago, D.O. ; Lievens, C. - \ 2019
Geomorphology 341 (2019). - ISSN 0169-555X - p. 28 - 45.
40 39 Ar/ Ar geochronology - Basalt flows - Delta - Fluvial terrace - Lahar
Geomorphological and sedimentary records near the confluences of the Tana River and major tributaries draining the eastern slopes of Mt. Kenya and the Nyambeni Range, indicate impacts of Late Quaternary volcanic activity in their fluvial records. The main reconstructed event was triggered by a 366.9 ka basalt flow (40Ar/39Ar dated) which flowed along Kazita River from the Nyambeni Range blocking both Kazita River and Tana River near Kibuka Grand Falls, causing a temporary lake. Consequently, Tana River and Kazita River started to build volcanoclastic Gilbert type deltas. The preserved pro-delta sediments rich in trachytic pumice fragments display a mineralogical and age match with known Ithanguni trachytic tuffs, indicating delta build up right after a contemporary Ithanguni eruption. This trachytic eruption caused the deposition of lahars and fluvial volcaniclastic sediments in all river records draining the Eastern side of Mt. Kenya. The multiple lahars seem to be triggered by eruptions under glacial conditions (basalt age indicates MIS 10). The lava dammed lake was only short lived (estimated to have lasted only a few years to decades) and breached before a complete lake infill could occur. The current Kibuka Grand Falls can be viewed as the delayed incisional response of this lava dam breach, indicating that after >366.9 ka, Tana River is still responding and adjusting to this short-lived disruptive phase. The current Kazita River has re-incised adjacent to a MIS 4 basalt flow down into the crystalline Basement System rocks. The MIS 10 pre-volcanic sedimentary record indicates that more sediments were in the fluvial system during glacial conditions than during the interglacial conditions. An implication of our reconstruction is that the Late Quaternary fluvial record of Tana River is of only limited use to reconstruct uplift rates because reconstructed Quaternary incision rates are reflecting both volcanic disruptions as climate change trends of aridification and decreasing glaciation extents.
Contrasting effects of host species and phylogenetic diversity on the occurrence of HPAI H5N1 in European wild birds
Huang, Zheng Y.X. ; Xu, Chi ; Langevelde, Frank van; Ma, Yuying ; Langendoen, Tom ; Mundkur, Taej ; Si, Yali ; Tian, Huaiyu ; Kraus, Robert H.S. ; Gilbert, Marius ; Han, Guan Zhu ; Ji, Xiang ; Prins, Herbert H.T. ; Boer, Willem F. de - \ 2019
Journal of Animal Ecology 88 (2019)7. - ISSN 0021-8790 - p. 1044 - 1053.
avian influenza - community composition - dilution effect - diversity–disease relationship - phylogenetic distance - waterfowl

Studies on the highly pathogenic avian influenza (HPAI) H5N1 suggest that wild bird migration may facilitate its long-distance spread, yet the role of wild bird community composition in its transmission risk remains poorly understood. Furthermore, most studies on the diversity–disease relationship focused on host species diversity without considering hosts’ phylogenetic relationships, which may lead to rejecting a species diversity effect when the community has host species that are only distantly related. Here, we explored the influence of waterbird community composition for determining HPAI H5N1 occurrence in wild birds in a continental-scale study across Europe. In particular, we tested the diversity–disease relationship using both host species diversity and host phylogenetic diversity. Our results provide the first demonstration that host community composition—compared with previously identified environmental risk factors—can also effectively explain the spatial pattern of H5N1 occurrence in wild birds. We further show that communities with more higher risk host species and more closely related species have a higher risk of H5N1 outbreaks. Thus, both host species diversity and community phylogenetic structure, in addition to environmental factors, jointly influence H5N1 occurrence. Our work not only extends the current theory on the diversity–disease relationship, but also has important implications for future monitoring of H5N1 and other HPAI subtypes.

A two-echelon inventory routing problem for perishable products
Rohmer, S.U.K. ; Claassen, G.D.H. ; Laporte, Gilbert - \ 2019
Computers and Operations Research 107 (2019). - ISSN 0305-0548 - p. 156 - 172.
Perishable products - Inventory-routing - Adaptive large neighbourhood search - Last-mile logistics - Two-echelon system
This paper presents a two-echelon inventory-routing problem for perishable products. Products are de- livered from a supplier to an intermediary depot, where storage may occur and from which they are delivered by smaller vehicles to the customer locations. Holding costs are incurred for storage at the de- pot. Customer availability is taken into account in the form of customer delivery patterns. The objective is to minimise the total transportation and holding costs. We formulate the problem as a mixed integer linear program and solve it by means of an adaptive large neighbourhood search metaheuristic in com- bination with the solution of a reduced formulation. Three variants of the heuristic are compared on a variety of randomly generated instances. Given the two-stage structure of the problem, computational results show the importance of taking the cost structure into account when choosing the most suitable solution approach.
Halophilic bacteria as a food source for the brine shrimp Artemia
Lopes-dos-Santos, R.M.A. ; Groot, Ruben ; Liying, Sui ; Bossier, Peter ; Stappen, Gilbert Van - \ 2019
Aquaculture 500 (2019). - ISSN 0044-8486 - p. 631 - 639.
Artemia - Cyst production - Gnotobiotic - Halophilic bacteria - Mono-diets

Artemia cysts are highly demanded by the aquaculture industry to be hatched into nauplii and used as live food for larvae of most farmed fish and shellfish species. In recent years, pond production of Artemia cysts has been proposed as an effective measure to reduce the high dependence of the industry on cysts harvested from wild populations. Nonetheless, the feeding management strategies of this type of intensive Artemia culture, focusing until now on costly phytoplankton boosting are still in need of optimization. The growth stimulation of the naturally occurring halophilic bacterial flora in the culture ponds, as a complementary food source for the Artemia nauplii, is currently being considered as a viable way to improve Artemia biomass and cyst production. Field studies conducted until now did not however, allow for patent conclusions about the actual dietary value of this bacterial biomass to the Artemia diet, hindering the widespread application of these practices. The purpose of this research was therefore to investigate the capacity of Artemia nauplii to survive and grow on diets consisting exclusively of mono-diets of live or dead biomass of six halophilic bacteria, belonging to genera commonly found in hypersaline environments where Artemia occur. To this end, a standard gnotobiotic Artemia culture system was used at a salinity relevant for a field situation (100 g l−1) and at seawater salinity (35 g l−1). The results showed that the addition of most tested halophilic bacteria, either as live or dead biomass, to the Artemia culture water, allowed for significantly superior nauplii survival than the corresponding negative control (starvation treatment). Furthermore, significantly higher individual length in comparison to the positive control (a standard marine bacterial diet used in Artemia gnotobiotic tests) was also observed, especially when feeding the nauplii with live halophilic bacteria biomass. The success at both salinities of the tested halophilic bacteria mono-diets when compared to both controls, clearly denoted that despite having a low nutritional value as far as fatty acids are concerned, they can be an intergral part of its diet during its first developmental stages. Although our findings need to be confirmed in field conditions, they are of importance for Artemia pond production as they confirm the potential of these microorganisms to be used as a viable dietary source, complementing the present focus on phytoplankton blooms to sustain Artemia populations.

Geomorfologische analyse van de Raamvallei
Maas, Gilbert ; Delft, Bas van; Mol, Gerben - \ 2018
Wageningen : Wageningen Environmental Research (Wageningen Environmental Research report 2918) - 79
Serious Games as planning support systems : Learning from playing maritime spatial planning challenge 2050
Jean, Steven ; Gilbert, Laura ; Medema, Wietske ; Keijser, Xander ; Mayer, Igor ; Inam, Azhar ; Adamowski, Jan - \ 2018
Water 10 (2018)12. - ISSN 2073-4441
Knowledge co-creation - Maritime spatial planning - Planning support systems - Serious games - Sustainability

The inherent complexity of planning at sea, called maritime spatial planning (MSP), requires a planning approach where science (data and evidence) and stakeholders (their engagement and involvement) are integrated throughout the planning process. An increasing number of innovative planning support systems (PSS) in terrestrial planning incorporate scientific models and data into multi-player digital game platforms with an element of role-play. However, maritime PSS are still early in their innovation curve, and the use and usefulness of existing tools still needs to be demonstrated. Therefore, the authors investigate the serious game, MSP Challenge 2050, for its potential use as an innovative maritime PSS and present the results of three case studies on participant learning in sessions of game events held in Newfoundland, Venice, and Copenhagen. This paper focusses on the added values of MSP Challenge 2050, specifically at the individual, group, and outcome levels, through the promotion of the knowledge co-creation cycle. During the three game events, data was collected through participant surveys. Additionally, participants of the Newfoundland event were audiovisually recorded to perform an interaction analysis. Results from survey answers and the interaction analysis provide evidence that MSP Challenge 2050 succeeds at the promotion of group and individual learning by translating complex information to players and creating a forum wherein participants can share their thoughts and perspectives all the while (co-) creating new types of knowledge. Overall, MSP Challenge and serious games in general represent promising tools that can be used to facilitate the MSP process.

Corrigendum: Fecal microbial composition associated with variation in feed efficiency in pigs depends on diet and sex
Verschuren, Lisanne M.G. ; Calus, Mario P.L. ; Jansman, Alfons J.M. ; Bergsma, Rob ; Knol, Egbert F. ; Gilbert, Hélène ; Zemb, Olivier - \ 2018
Journal of Animal Science 96 (2018)9. - ISSN 0021-8812 - p. 4013 - 4013.
Post-weaning diarrhoea in piglets in practice is associated with protein fermentation, but specific protein fermentation metabolites contribute differently
Gilbert, M.S. ; Hee, B. van der; Gulersonmez, M. ; Stigter, E. ; Kies, Arie ; Gerrits, W.J.J. - \ 2018
Post-weaning diarrhoea in piglets in practice is associated with protein fermentation, but specific protein fermentation metabolites contribute differently
Gilbert, Myrthe - \ 2018
Nederlandse steden en hun ondergrond : testboek
Grond, Vincent ; Maas, Gilbert ; Timmermans, Wim ; Broks, Kees - \ 2018
Amersfoort : Stowa (Stowa rapport 2018-64) - 67
Quantifying the environmental and economic benefits of cooperation : A case study in temperature-controlled food logistics
Stellingwerf, Helena M. ; Laporte, Gilbert ; Cruijssen, Frans C.A.M. ; Kanellopoulos, Argyris ; Bloemhof, Jacqueline M. - \ 2018
Transportation Research. Part D, Transport and Environment 65 (2018). - ISSN 1361-9209 - p. 178 - 193.
CO emissions - Fresh food - Inventory - Logistics - Route optimization

Inefficient road transportation causes unnecessary costs and polluting emissions. This problem is even more severe in refrigerated transportation, in which temperature control is used to guarantee the quality of the products. Organizing logistics cooperatively can help decrease both the environmental and the economic impacts. In Joint Route Planning (JRP) cooperation, suppliers and customers jointly optimize routing decisions so that cost and emissions are minimized. Vendor Managed Inventory (VMI) cooperation extends JRP cooperation by optimizing routing and inventory planning decisions simultaneously. However, in addition to their economic advantages, VMI and JRP may also yield environmental benefits. To test this assertion, we perform a case study on cooperation between a number of supermarket chains in the Netherlands. The data of this case study are analyzed to quantify both the economic and environmental benefits of implementing cooperation via JRP and VMI, using vehicle routing and an inventory routing models. We found that JRP cooperation can substantially reduce cost and emissions compared with uncooperative routing. In addition, VMI cooperation can further reduce cost and emissions, but minimizing cost and minimizing emissions no longer result in the same solution and there is a trade-off to be made.

Protein fermentation in the gut; implications for intestinal dysfunction in humans, pigs, and poultry
Gilbert, Myrthe S. ; IJssennagger, Noortje ; Kies, Arie K. ; Mil, Saskia W.C. van - \ 2018
American Journal of Physiology. Gastrointestinal and Liver Physiology 315 (2018)2. - ISSN 0193-1857 - p. G159 - G170.
Broiler - Gut health - Human - Intestinal disease - Metabolomics - Pig - Protein fermentation

The amount of dietary protein is associated with intestinal disease in different vertebrate species. In humans, this is exemplified by the association between high-protein intake and fermentation metabolite concentrations in patients with inflammatory bowel disease. In production animals, dietary protein intake is associated with postweaning diarrhea in piglets and with the occurrence of wet litter in poultry. The underlying mechanisms by which dietary protein contributes to intestinal problems remain largely unknown. Fermentation of undigested protein in the hindgut results in formation of fermentation products including short-chain fatty acids, branchedchain fatty acids, ammonia, phenolic and indolic compounds, biogenic amines, hydrogen sulfide, and nitric oxide. Here, we review the mechanisms by which these metabolites may cause intestinal disease. Studies addressing how different metabolites induce epithelial damage rely mainly on cell culture studies and occasionally on mice or rat models. Often, contrasting results were reported. The direct relevance of such studies for human, pig, and poultry gut health is therefore questionable and does not suffice for the development of interventions to improve gut health. We discuss a roadmap to improve our understanding of gut metabolites and microbial species associated with intestinal health in humans and production animals and to determine whether these metabolite/bacterial networks cause epithelial damage. The outcomes of these studies will dictate proof-of-principle studies to eliminate specific metabolites and or bacterial strains and will provide the basis for interventions aiming to improve gut health.

Homologous recombination between genetically divergent campylobacter fetus lineages supports host-associated speciation
Gilbert, Maarten J. ; Duim, Birgitta ; Graaf-van Bloois, Linda van der; Wagenaar, Jaap A. ; Zomer, Aldert L. - \ 2018
Genome Biology and Evolution 10 (2018)3. - ISSN 1759-6653 - p. 716 - 722.
Campylobacter fetus - Homologous recombination - Host association - Reptile - Speciation - Whole genome sequencing

Homologous recombination is a major driver of bacterial speciation. Genetic divergence and host association are important factors influencing homologous recombination. Here, we study these factors for Campylobacter fetus, which shows a distinct intraspecific host dichotomy. Campylobacter fetus subspecies fetus (Cff) and venerealis are associated with mammals, whereas C. fetus subsp. testudinum (Cft) is associated with reptiles. Recombination between these genetically divergent C. fetus lineages is extremely rare. Previously it was impossible to show whether this barrier to recombination was determined by the differential host preferences, by the genetic divergence between both lineages or by other factors influencing recombination, such as restriction-modification, CRISPR/Cas, and transformation systems. Fortuitously, a distinct C. fetus lineage (ST69) was found, which was highly related to mammal-associated C. fetus, yet isolated from a chelonian. The whole genome sequences of two C. fetus ST69 isolates were compared with those of mammal- and reptile-associated C. fetus strains for phylogenetic and recombination analysis. In total, 5.1-5.5% of the core genome of both ST69 isolates showed signs of recombination. Of the predicted recombination regions, 80.4% were most closely related to Cft, 14.3% to Cff, and 5.6% to C. iguaniorum. Recombination from C. fetus ST69 to Cft was also detected, but to a lesser extent and only in chelonian-associated Cft strains. This study shows that despite substantial genetic divergence no absolute barrier to homologous recombination exists between two distinct C. fetus lineages when occurring in the same host type, which provides valuable insights in bacterial speciation and evolution.

Campylobacter blaseri sp. Nov., isolated from common seals (Phoca vitulina)
Gilbert, Maarten J. ; Zomer, Aldert L. ; Timmerman, Arjen J. ; Spaninks, Mirlin P. ; Rubio-García, Ana ; Rossen, John W. ; Duim, Birgitta ; Wagenaar, Jaap A. - \ 2018
International Journal of Systematic and Evolutionary Microbiology 68 (2018)5. - ISSN 1466-5026 - p. 1787 - 1794.
Average nucleotide identity - Campylobacter - Common seal - Core genome phylogeny - Microbiome - Novel species
During a study to assess the faecal microbiome of common seals (Phoca vitulina) in a Dutch seal rehabilitation centre, 16S rRNA gene sequences of an unknown Campylobacter taxon were identified. Campylobacter isolates, which differed from the established Campylobacter taxa, were cultured and their taxonomic position was determined by a polyphasic study based on ten isolates. The isolates were characterized by 16S rRNA and atpA gene sequence analyses and by conventional phenotypic testing. Based on the whole genome sequences, the average nucleotide identity and core genome phylogeny were determined. The isolates formed a separate phylogenetic clade, divergent from all other Campylobacter taxa and most closely related to Campylobacter corcagiensis, Campylobacter geochelonis and Campylobacter ureolyticus. The isolates can be distinguished phenotypically from all other Campylobacter taxa based on their lack of motility, growth at 25 °C and growth on MacConkey agar. This study shows that these isolates represent a novel species within the genus Campylobacter, for which the name Campylobacter blaseri sp. nov. is proposed. The type strain for this novel species is 17S00004-5T (=LMG 30333T=CCUG 71276T).
Fecal microbial composition associated with variation in feed efficiency in pigs depends on diet and sex
Verschuren, Lisanne M.G. ; Calus, Mario P.L. ; Jansman, Alfons J.M. ; Bergsma, Rob ; Knol, Egbert F. ; Gilbert, Hélène ; Zemb, Olivier - \ 2018
Journal of Animal Science 96 (2018)4. - ISSN 0021-8812 - p. 1405 - 1418.
Diet - Fecal microbiome - Feed efficiency - Pig - Sex
Dietary fiber content and composition affect microbial composition and activity in the gut, which in turn influence energetic contribution of fermentation products to the metabolic energy supply in pigs. This may affect feed efficiency (FE) in pigs. The present study investigated the relationship between the fecal microbial composition and FE in individual growing-finishing pigs. In addition, the effects of diet composition and sex on the fecal microbiome were studied. Fecal samples were collected of 154 grower-finisher pigs (3-way crossbreeds) the day before slaughter. Pigs were either fed a diet based on corn/soybean meal (CS) or a diet based on wheat/barley/by-products (WB). Fecal microbiome was characterized by 16S ribosomal DNA sequencing, clustered by operational taxonomic unit (OTU), and results were subjected to a discriminant approach combined with principal component analysis to discriminate diets, sexes, and FE extreme groups (10 high and 10 low FE pigs for each diet by sex-combination). Pigs on different diets and males vs. females had a very distinct fecal microbiome, needing only 2 OTU for diet (P = 0.020) and 18 OTU for sex (P = 0.040) to separate the groups. The 2 most important OTU for diet, and the most important OTU for sex, were taxonomically classified as the same bacterium. In pigs fed the CS diet, there was no significant association between FE and fecal microbiota composition based on OTU (P > 0.05), but in pigs fed the WB diet differences in FE were associated with 17 OTU in males (P = 0.018) and to 7 OTU in females (P = 0.010), with 3 OTU in common for both sexes. In conclusion, our results showed a diet and sex-dependent relationship between FE and the fecal microbial composition at slaughter weight in grower-finisher pigs.
Ranavirus genotypes in Netherlands and their potential association with virulence in water frogs (Pelophylax spp.) article
Saucedo, Bernardo ; Hughes, Joseph ; Spitzen-Van Der Sluijs, Annemarieke ; Kruithof, Natasja ; Schills, Marc ; Rijks, Jolianne M. ; Jacinto-Maldonado, Mónica ; Suarez, Nicolás ; Haenen, Olga L.M. ; Voorbergen-Laarman, Michal ; Broek, Jan Van Den; Gilbert, Maarten ; Gröne, Andrea ; Beurden, Steven J. Van; Verheije, M.H. - \ 2018
Emerging Microbes and Infections 7 (2018)1. - ISSN 2222-1751
Ranaviruses are pathogenic viruses for poikilothermic vertebrates worldwide. The identification of a common midwife toad virus (CMTV) associated with massive die-offs in water frogs (Pelophylax spp.) in Netherlands has increased awareness for emerging viruses in amphibians in the country. Complete genome sequencing of 13 ranavirus isolates collected from ten different sites in the period 2011-2016 revealed three CMTV groups present in distinct geographical areas in Netherlands. Phylogenetic analysis showed that emerging viruses from the northern part of Netherlands belonged to CMTV-NL group I. Group II and III viruses were derived from the animals located in the center-east and south of the country, and shared a more recent common ancestor to CMTV-amphibian associated ranaviruses reported in China, Italy, Denmark, and Switzerland. Field monitoring revealed differences in water frog host abundance at sites where distinct ranavirus groups occur; with ranavirus-associated deaths, host counts decreasing progressively, and few juveniles found in the north where CMTV-NL group I occurs but not in the south with CMTV-NL group III. Investigation of tandem repeats of coding genes gave no conclusive information about phylo-geographical clustering, while genetic analysis of the genomes revealed truncations in 17 genes across CMTV-NL groups II and III compared to group I. Further studies are needed to elucidate the contribution of these genes as well as environmental variables to explain the observed differences in host abundance.
Short communication : Supplementation of fructo-oligosaccharides does not improve insulin sensitivity in heavy veal calves fed different sources of carbohydrates
Pantophlet, Andre J. ; Gilbert, M.S. ; Gerrits, W.J.J. ; Vonk, R.J. - \ 2017
Journal of Dairy Science 100 (2017)11. - ISSN 0022-0302 - p. 9442 - 9446.
Fructo-oligosaccharides - Insulin sensitivity - Milk replacer - Veal calf

Heavy veal calves (4-6 mo old) often develop problems with insulin sensitivity. This could lead to metabolic disorders and impaired animal growth performance. Studies in various animal species have shown that the supplementation of short-chain fructo-oligosaccharides (scFOS) can improve insulin sensitivity. We therefore studied the effects of scFOS supplementation on insulin sensitivity in heavy veal calves. Forty male Holstein-Friesian calves (BW = 190 ± 2.9 kg; age = 162 ± 1.4 d at the start of the trial) were fed either a control milk replacer (MR) diet or a diet in which one-third of the lactose was replaced by glucose, fructose, or glycerol for 10 wk prior to the start of the trial. At the start of the trial, calves were subjected to a frequently sampled intravenous glucose tolerance test to assess whole-body insulin sensitivity (muscle and hepatic insulin sensitivity). Calves within each dietary treatment group were ranked based on their insulin sensitivity value. Half of the calves received scFOS (12 mg/kg of BW) with the MR for 6 wk (supplementation was equally distributed over the insulin sensitivity range). Subsequently, a second frequently sampled intravenous glucose tolerance test was conducted to assess the effect of scFOS. In addition, fasting plasma levels of glucose, insulin, triglycerides, and cholesterol were determined to calculate the quantitative insulin sensitivity check index and triglyceride:high-density lipoprotein cholesterol ratio (fasting indicators of insulin sensitivity). Whole-body insulin sensitivity was low at the start of the trial and remained low in all groups [1.0 ± 0.1 and 0.8 ± 0.1 (mU/L)-1 · min-1 on average, respectively]. Supplementation of scFOS did not improve insulin sensitivity in any of the treatment groups. The quantitative insulin sensitivity check index and the triglyceride:high-density lipoprotein cholesterol ratio also did not differ between scFOS and non-scFOS calves and averaged 0.326 ± 0.003 and 0.088 ± 0.004, respectively, at the end of the trial. We conclude that scFOS supplementation does not improve insulin sensitivity in heavy veal calves regardless of the carbohydrate composition of the MR. This is in contrast to other animals (e.g., dogs and horses), where scFOS supplementation did improve insulin sensitivity. The absence of an effect of scFOS might be related to the dosage or to metabolic differences between ruminants and nonruminants. Increasing evidence indicates that dietary interventions in veal calves have little or no effect on insulin sensitivity, possibly because of low levels of insulin sensitivity.

Feed efficiency and the faecal microbiome at slaughter weight in pigs
Verschuren, L.M.G. ; Calus, M.P.L. ; Jansman, A.J.M. ; Bergsma, R. ; Knol, E.F. ; Gilbert, H. ; Zemb, O. - \ 2017
- 1 p.
Feed efficiency (FE) is an important trait in the pig industry, as feed costs are responsible for the major part of production costs. Availability in the market and cost of feed ingredients dictate changes in feed composition. As a result, fibre level and composition can vary between pig diets. Microbiota in the gastrointestinal tract play an important role in fibre digestion, because they produce enzymes that break down fibre structures and deliver volatile fatty acids to the pig. These volatile fatty acids can be used as metabolic energy source. As such, microbial fermentation could influence FE in pigs. The aim of this study was to investigate the association between FE and faecal microbiome in commercial grower-finisher pigs. Three-way crossbreed grower-finisher pigs (154) were either fed a diet based on corn/soybean meal (CS) or a diet based on wheat/barley (WB). Faecal samples were collected on the day before slaughter (mean bodyweight 122 kg) and sequenced for the V3V4 16S ribosomal DNA regions. Sequences were clustered according to operational taxonomic units (OTU) for each individual, forming a table of OTU abundancy. A partial least square regression was applied to the dataset, together with a discriminant analysis using principal components of FE extreme groups (10 high and 10 low FE animals for each diet x sex-combination). Pigs on different diets and males vs. females had a very distinct microbiome, needing only two OTUs for diet (P=0.018) and 18 OTUs for sex (P=0.002) to separate the groups. Faecal microbiome was not related to FE groups fed the CS diet, but there were sex specific OTUs related to FE in the male and female pigs in the groups fed the WB diet. In conclusion, our results show a diet and sex dependent relationship between the faecal microbial composition and FE in grower-finisher pigs at slaughter weight. This study is part of the Feed-a-Gene Project, funded from the European Union’s H2020 Programme under grant agreement no 633531.
Whole genome-based phylogeny of reptile-associated Helicobacter indicates independent niche adaptation followed by diversification in a poikilothermic host
Gilbert, Maarten J. ; Duim, Birgitta ; Timmerman, Arjen J. ; Zomer, Aldert L. ; Wagenaar, Jaap A. - \ 2017
Scientific Reports 7 (2017). - ISSN 2045-2322 - 8 p.

Reptiles have been shown to host a significant Helicobacter diversity. In order to survive, reptile-associated Helicobacter lineages need to be adapted to the thermally dynamic environment encountered in a poikilothermic host. The whole genomes of reptile-associated Helicobacter lineages can provide insights in Helicobacter host adaptation and coevolution. These aspects were explored by comparing the genomes of reptile-, bird-, and mammal-associated Helicobacter lineages. Based on average nucleotide identity, all reptile-associated Helicobacter lineages in this study could be considered distinct species. A whole genome-based phylogeny showed two distinct clades, one associated with chelonians and one associated with lizards. The phylogeny indicates initial adaptation to an anatomical niche, which is followed by an ancient host jump and subsequent diversification. Furthermore, the ability to grow at low temperatures, which might reflect thermal adaptation to a reptilian host, originated at least twice in Helicobacter evolution. A putative tricarballylate catabolism locus was specifically present in Campylobacter and Helicobacter isolates from reptiles. The phylogeny of reptile-associated Helicobacter parallels host association, indicating a high level of host specificity. The high diversity and deep branching within these clades supports long-term coevolution with, and extensive radiation within the respective reptilian host type.

Only 7% of the variation in feed efficiency in veal calves can be predicted from variation in feeding motivation, digestion, metabolism, immunology, and behavioral traits in early life
Gilbert, M.S. ; Borne, J.J.G.C. van den; Reenen, C.G. van; Gerrits, W.J.J. - \ 2017
Journal of Dairy Science 100 (2017)10. - ISSN 0022-0302 - p. 8087 - 8101.
Feed efficiency - Glycerol - Growth performance - Lactose - Veal calf

High interindividual variation in growth performance is commonly observed in veal calf production and appears to depend on milk replacer (MR) composition. Our first objective was to examine whether variation in growth performance in healthy veal calves can be predicted from early life characterization of these calves. Our second objective was to determine whether these predictions differ between calves that are fed a high- or low-lactose MR in later life. A total of 180 male Holstein-Friesian calves arrived at the facilities at 17 ± 3.4 d of age, and blood samples were collected before the first feeding. Subsequently, calves were characterized in the following 9 wk (period 1) using targeted challenges related to traits within each of 5 categories: feeding motivation, digestion, postabsorptive metabolism, behavior and stress, and immunology. In period 2 (wk 10-26), 130 calves were equally divided over 2 MR treatments: a control MR that contained lactose as the only carbohydrate source and a low-lactose MR in which 51% of the lactose was isocalorically replaced by glucose, fructose, and glycerol (2:1:2 ratio). Relations between early life characteristics and growth performance in later life were assessed in 117 clinically healthy calves. Average daily gain (ADG) in period 2 tended to be greater for control calves (1,292 ± 111 g/d) than for calves receiving the low-lactose MR (1,267 ± 103 g/d). Observations in period 1 were clustered per category using principal component analysis, and the resulting principal components were used to predict performance in period 2 using multiple regression procedures. Variation in observations in period 1 predicted 17% of variation in ADG in period 2. However, this was mainly related to variation in solid feed refusals. When ADG was adjusted to equal solid feed intake, only 7% of the variation in standardized ADG in period 2, in fact reflecting feed efficiency, could be explained by early life measurements. This indicates that >90% of the variation in feed efficiency in later life could not be explained by early life characterization of the calves. It is speculated that variation in health status explains a substantial portion of variation in feed efficiency in later life. Significant relations between fasting plasma glucose concentrations, fecal pH, drinking speed, and plasma natural antibodies in early life (i.e., not exposed to the lactose replacer) and feed efficiency in later life depended on MR composition. These measurements are therefore potential tools for screening calves in early life on their ability to cope with MR varying in lactose content.

Campylobacter pinnipediorum sp. Nov., isolated from pinnipeds, comprising Campylobacter pinnipediorum subsp. pinnipediorum subsp. nov. and Campylobacter pinnipediorum subsp. caledonicus subsp. nov
Gilbert, Maarten J. ; Miller, William G. ; St. Leger, Judy ; Chapman, Mary H. ; Timmerman, Arjen J. ; Duim, Birgitta ; Foster, Geoffrey ; Wagenaar, Jaap A. - \ 2017
International Journal of Systematic and Evolutionary Microbiology 67 (2017)6. - ISSN 1466-5026 - p. 1961 - 1968.
Average nucleotide identity - Campylobacter - Novel species - Pinnipeds - Urease - Whole genome sequencing

During independent diagnostic screenings of otariid seals in California (USA) and phocid seals in Scotland (UK), Campylobacter-like isolates, which differed from the established taxa of the genus Campylobacter, were cultured from abscesses and internal organs of different seal species. A polyphasic study was undertaken to determine the taxonomic position of these six isolates. The isolates were characterized by 16S rRNA gene and AtpA sequence analysis and by conventional phenotypic testing. The whole-genome sequences were determined for all isolates, and the average nucleotide identity (ANI) was determined. The isolates formed a separate phylogenetic clade, divergent from all other taxa of the genus Campylobacter and most closely related to Campylobactermucosalis. Although all isolates showed 100 % 16S rRNA gene sequence homology, AtpA and ANI analyses indicated divergence between the otariid isolates from California and the phocid isolates from Scotland, which warrants subspecies status for each clade. The two subspecies could also be distinguished phenotypically on the basis of catalase activity. This study shows clearly that the isolates obtained from pinnipeds represent a novel species within the genus Campylobacter, for which the name Campylobacter pinnipediorum sp. nov. is proposed. Within this novel species, the Californian isolates represent a separate subspecies, for which the name C. pinnipediorum subsp. pinnipediorum subsp. nov. is proposed. The type strain for both this novel species and subspecies is RM17260T (=LMG 29472T=CCUG 69570T). The Scottish isolates represent another subspecies, for which the name C. pinnipediorum subsp. caledonicus subsp. nov. is proposed. The type strain of this subspecies is M302/10/6T (=LMG 29473T=CCUG 68650T).

Connecting Earth observation to high-throughput biodiversity data
Bush, Alex ; Sollmann, Rahel ; Wilting, Andreas ; Bohmann, Kristine ; Cole, Beth ; Balzter, Heiko ; Martius, Christopher ; Zlinszky, András ; Calvignac-Spencer, Sébastien ; Cobbold, Christina A. ; Dawson, Terence P. ; Emerson, Brent C. ; Ferrier, Simon ; Gilbert, M.T.P. ; Herold, Martin - \ 2017
Nature Ecology & Evolution 1 (2017)7. - ISSN 2397-334X - 9 p.
Understandably, given the fast pace of biodiversity loss, there is much interest in using Earth observation technology to track
biodiversity, ecosystem functions and ecosystem services. However, because most biodiversity is invisible to Earth observation,
indicators based on Earth observation could be misleading and reduce the effectiveness of nature conservation and even
unintentionally decrease conservation effort. We describe an approach that combines automated recording devices, highthroughput
DNA sequencing and modern ecological modelling to extract much more of the information available in Earth
observation data. This approach is achievable now, offering efficient and near-real-time monitoring of management impacts
on biodiversity and its functions and services.
Measuring temporal liking simultaneously to Temporal Dominance of Sensations in several intakes. An application to Gouda cheeses in 6 Europeans countries
Thomas, A. ; Chambault, M. ; Dreyfuss, L. ; Gilbert, C.C. ; Hegyi, A. ; Henneberg, S. ; Knippertz, A. ; Kostyra, E. ; Kremer, S. ; Silva, A.P. ; Schlich, P. - \ 2017
Food Research International 99 (2017)1. - ISSN 0963-9969 - p. 426 - 434.
Gouda cheese - Liking - Temporal Dominance of Sensations (TDS) - Temporal Drivers of Liking (TDL)
The idea of having untrained consumers performing Temporal Dominance of Sensations (TDS) and dynamic liking in the same session was recently introduced (Thomas, van der Stelt, Prokop, Lawlor, & Schlich, 2016). In the present study, a variation of the data acquisition protocol was done, aiming to record TDS and liking simultaneously on the same screen in a single session during multiple product intakes. This method, called Simultaneous Temporal Drivers of Liking (S-TDL), was used to describe samples of Gouda cheese in an international experiment.To test this idea, consumers from six European countries (n = 667) assessed 4 Gouda cheeses with different ages and fat contents during one sensory evaluation session. Ten sensory attributes and a 9-point hedonic scale were presented simultaneously on the computer screen. While performing TDS, consumers could reassess their liking score as often as they wanted. This new type of sensory data was coded by individual average liking scores while a given attribute was perceived as dominant (Liking While Dominant; LWD).Although significant differences in preference were observed among countries, there were global preferences for a longer dominance of melting, fatty and tender textures. The cheese flavour attribute was the best positive TDL, whereas bitter was a strong negative TDL. A cluster analysis of the 667 consumers identified three significant liking clusters, each with different most and least preferred samples. For the TDL computation by cluster, significant specific TDL were observed. These results showed the importance of overall liking segmentation before TDL analysis to determine which attributes should have a longer dominance duration in order to please specific consumer targets.
Green compressed fluid technologies for downstream processing of Scenedesmus obliquus in a biorefinery approach
Gilbert-López, Bienvenida ; Mendiola, José A. ; Broek, Lambertus A.M. van den; Houweling-Tan, Bwee ; Sijtsma, Lolke ; Cifuentes, Alejandro ; Herrero, Miguel ; Ibáñez, Elena - \ 2017
Algal Research 24 (2017). - ISSN 2211-9264 - p. 111 - 121.
Algae - Biorefinery - Carotenoid - Lipid - Pressurized liquid extraction - Supercritical fluid extraction

The fractionation of algae biomass in several high-value compounds that can be used as ingredients in other applications sets the basis of the algae biorefinery approach. The present study aimed at the extraction and fractionation of bioactive compounds from the microalga Scenedesmus obliquus, by means of applying a sequential process without the manipulation of the biomass in the extraction cell. This integrated platform of compressed fluid extraction technologies of low-environmental impact was designed in order to produce increases of solvent polarity using non-toxic solvents. The process involved the following steps:(1) supercritical fluid extraction (SFE) using supercritical carbon dioxide (ScCO2); (2) gas expanded liquids (GXL) using 75% ethanol and 25% ScCO2 (v/v) and; (3) pressurized liquid extraction (PLE) using water. Extraction conditions were optimized using response surface methodology (RSM) and kinetic studies. Extraction yield, antioxidant activity as well as contents of total phenols, carotenoids, proteins and sugars were the studied response variables. High performance liquid chromatography coupled to evaporative light-scattering detector (HPLC-ELSD) analyses of the fractions revealed that triacylglycerols were mainly extracted by SFE. Lutein and β-carotene were the main pigments identified in the extracts by HPLC coupled to diode array and mass spectrometry detectors (HPLC-DAD-MS/MS), which were preferentially extracted in the GXL step. Polar compounds such as proteins and sugars remained predominantly in the residue. Therefore, the green downstream platform developed in this study for valorization of the microalgae biomass, is able to produce different fractions with potential application in the food, pharmaceutical and cosmetic industries.

Comparative Genomics of Campylobacter fetus from Reptilesand Mammals Reveals Divergent Evolution in Host-Associated Lineages
Gilbert, Maarten J. ; Miller, William G. ; Yee, Emma ; Zomer, Aldert ; Graaf-Van Bloois, Linda Van Der; Fitzgerald, C. ; Forbes, Ken J. ; Méric, Guillaume ; Sheppard, S. ; Wagenaar, J.A. ; Duim, Birgitta - \ 2016
Genome Biology and Evolution 8 (2016)6. - ISSN 1759-6653 - p. 2006 - 2019.
Campylobacter fetus currently comprises three recognized subspecies, which display distinct host association. Campylobacter fetus subsp. fetus and C. fetus subsp. venerealis are both associated with endothermic mammals, primarily ruminants, whereas C. fetus subsp. testudinum is primarily associated with ectothermic reptiles. Both C. fetus subsp. testudinum and C. fetus subsp. fetus have been associated with severe infections, often with a systemic component, in immunocompromised humans. To study the genetic factors associated with the distinct host dichotomy in C. fetus, whole-genome sequencing and comparison of mammal- and reptile-associated C. fetus was performed. The genomes of C. fetus subsp. testudinum isolated from either reptiles or humans were compared with elucidate the genetic factors associated with pathogenicity in humans. Genomic comparisons showed conservation of gene content and organization among C. fetus subspecies, but a clear distinction between mammal- and reptile-associated C. fetus was observed. Several genomic regions appeared to be subspecies specific, including a putative tricarballylate catabolism pathway, exclusively present in C. fetus subsp. testudinum strains. Within C. fetus subsp. testudinum, sapA, sapB, and sapAB type strains were observed. The recombinant locus iamABC (mlaFED) was exclusively associated with invasive C. fetus subsp. testudinum strains isolated from humans. A phylogenetic reconstruction was consistent with divergent evolution in host-associated strains and the existence of a barrier to lateral gene transfer between mammal- and reptile-associated C. fetus. Overall, this study shows that reptile-associated C. fetus subsp. testudinum is genetically divergent from mammal-associated C. fetus subspecies.
Safe food and feed through an integrated toolbox for mycotoxin management: the MyToolBox approach
Krska, R. ; Nijs, M. De; Mcnerney, O. ; Pichler, M. ; Gilbert, J. ; Edwards, S. ; Suman, M. ; Magan, N. ; Rossi, V. ; Fels, Ine van der; Bagi, F. ; Poschmaier, B. ; Sulyok, M. ; Berthiller, F. ; Egmond, H.P. Van - \ 2016
World Mycotoxin Journal 9 (2016)4. - ISSN 1875-0710 - p. 487 - 495.
There is a pressing need to mobilise the wealth of knowledge from the international mycotoxin research conductedover the past 25-30 years, and to perform cutting-edge research where knowledge gaps still exist. This knowledgeneeds to be integrated into affordable and practical tools for farmers and food processors along the chain inorder to reduce the risk of mycotoxin contamination of crops, feed and food. This is the mission of MyToolBox – a four-year project which has received funding from the European Commission. It mobilises a multi-actorpartnership (academia, farmers, technology small and medium sized enterprises, food industry and policystakeholders) to develop novel interventions aimed at achieving a significant reduction in crop losses due tomycotoxin contamination. Besides a field-to-fork approach, MyToolBox also considers safe use options ofcontaminated batches, such as the efficient production of biofuels. Compared to previous efforts of mycotoxin reduction strategies, the distinguishing feature of MyToolBox is to provide the recommended measures to theend users along the food and feed chain in a web-based MyToolBox platform (e-toolbox). The project focuseson small grain cereals, maize, peanuts and dried figs, applicable to agricultural conditions in the EU and China. Crop losses using existing practices are being compared with crop losses after novel pre-harvest interventionsincluding investigation of genetic resistance to fungal infection, cultural control (e.g. minimum tillage or cropdebris treatment), the use of novel biopesticides suitable for organic farming, competitive biocontrol treatment and development of novel modelling approaches to predict mycotoxin contamination. Research into post-harvestmeasures includes real-time monitoring during storage, innovative sorting of crops using vision-technology, novelmilling technology and studying the effects of baking on mycotoxins at an industrial scale.
Predicting variation in feed efficiency in veal calves by early life characterization
Gilbert, M.S. ; Borne, J.J.G.C. van den; Reenen, C.G. van; Gerrits, W.J.J. - \ 2016
In: Energy and protein metabolism and nutrition. - Wageningen Academic Publishers (EAAP publication 137) - ISBN 9789086862863 - p. 75 - 76.
Predicting variation in feed efficiency in veal calves by early life characterization
Gilbert, Myrthe - \ 2016
Comparative genomics of campylobacter iguaniorum to unravel genetic regions associated with reptilian hosts
Gilbert, Maarten J. ; Miller, William G. ; Yee, Emma ; Kik, Marja ; Zomer, Aldert L. ; Wagenaar, Jaap A. ; Duim, Birgitta - \ 2016
Genome Biology and Evolution 8 (2016)9. - ISSN 1759-6653 - p. 3022 - 3029.
Campylobacter Iguaniorum - Comparative Genomics - Evolution - Phylogeny - Recombination - Reptile

Campylobacter iguaniorum is most closely related to the species C. fetus, C. hyointestinalis, andC. lanienae. Reptiles, chelonians and lizards in particular, appear to be a primary reservoir of this Campylobacter species. Here we report the genome comparison of C. iguaniorumstrain 1485E, isolated from a bearded dragon (Pogona vitticeps), and strain 2463D, isolated froma green iguana (Iguana iguana), with the genomes of closely related taxa, in particular with reptile-Associated C. fetus subsp.Testudinum. In contrast to C. fetus, C. iguaniorum is lacking an S-layer encoding region. Furthermore, a defined lipooligosaccharide biosynthesis locus, encoding multiple glycosyltransferases and bounded by waa genes, is absent from C. iguaniorum. Instead, multiple predicted glycosylation regionswere identified inC. iguaniorum.One of these regions is>50 kb withdeviantG+Ccontent, suggesting acquisition via lateral transfer. These similar, but non-homologous glycosylation regions were located at the same position on the genome in both strains. Multiple genes encoding respiratory enzymes not identified to date within the C. fetus clade were present. C. iguaniorum shared highest homology with C. hyointestinalis and C. fetus. As in reptile-Associated C. fetus subsp.Testudinum, a putative tricarballylate catabolism locus was identified. However, despite colonizing a shared host, no recent recombination between both taxa was detected. This genomic study provides a better understanding of host adaptation, virulence, phylogeny, and evolution of C. iguaniorum and related Campylobacter taxa.

Herstel en ontwikkeling van laagdynamische, aquatische systemen in het rivierengebied
Arts, Gertie ; Verdonschot, Ralf ; Maas, Gilbert ; Massop, Harry ; Ottburg, Fabrice ; Weeda, Eddy - \ 2016
Driebergen : Vereniging van Bos- en Natuurterreineigenaren, VBNE (Alterra-rapport 2729) - 128
aquatische ecosystemen - aquatisch milieu - ecologisch herstel - rivierengebied - nederland - aquatic ecosystems - aquatic environment - ecological restoration - netherlands
Na een inleiding (Hoofdstuk 1) beschrijft het rapport achtereenvolgens de macro-evertebraten (Hoofdstuk 2); de vissen, amfibieën en reptielen (Hoofdstuk 3); en de waterplanten van het rivierengebied (Hoofdstuk 4). Hoofdstuk 5 beschrijft de uitgevoerde GIS analyse en presenteert de resultaten en de kansenkaarten. Alle gegenereerde kaarten zijn opgenomen in twee bijlagerapporten. Hoofdstuk 6 geeft een discussie van het uitgevoerde onderzoek ten aanzien van de methode, de beschikbare gegevens en de analyse en plaatst de resultaten in het licht van uitgevoerde herstelmaatregelen in het rivierengebied. Hoofdstuk 7 vat de voornaamste conclusies samen. Hoofdstuk 8 geeft een overzicht van de gebruikte literatuur.
Insulin sensitivity in calves decreases substantially during the first 3 months of life and is unaffected by weaning or fructo-oligosaccharide supplementation
Pantophlet, A.J. ; Gilbert, M.S. ; Borne, J.J.G.C. van den; Gerrits, W.J.J. ; Priebe, M.G. ; Vonk, R.J. - \ 2016
Journal of Dairy Science 99 (2016)9. - ISSN 0022-0302 - p. 7602 - 7611.
Veal calves at the age of 4 to 6 mo often experience problems with glucose homeostasis, as indicated by postprandial hyperglycemia, hyperinsulinemia, and insulin resistance. It is not clear to what extent the ontogenetic development of calves or the feeding strategy [e.g., prolonged milk replacer (MR) feeding] contribute to this pathology. The objective of this study was therefore to analyze effects of MR feeding, weaning, and supplementation of short-chain fructo-oligosaccharides (FOS) on the development of glucose homeostasis and insulin sensitivity in calves during the first 3 mo of life. Thirty male Holstein-Friesian calves (18 ± 0.7 d of age) were assigned to 1 of 3 dietary treatments: the control (CON) group received MR only, the FOS group received MR with the addition of short-chain FOS, and the solid feed (SF) group was progressively weaned to SF. The CON and FOS calves received an amount of MR, which gradually increased (from 400 to 1,400 g/d) during the 71-d trial period. For the SF calves, the amount of MR increased from 400 to 850 g/d at d 30, and then gradually decreased, until completely weaned to only SF at d 63. The change in whole body insulin sensitivity was assessed by intravenous glucose tolerance tests. Milk tolerance tests were performed twice to assess changes in postprandial blood glucose, insulin, and nonesterified fatty acid responses. Whole-body insulin sensitivity was high at the start (16.7 ± 1.6 × 10−4 [μU/mL]−1), but decreased with age to 4.2 ± 0.6 × 10−4 [μU/mL]−1 at the end of the trial. The decrease in insulin sensitivity was most pronounced (∼70%) between d 8 and 29 of the trial. Dietary treatments did not affect the decrease in insulin sensitivity. For CON and FOS calves, the postprandial insulin response was 3-fold higher at the end of the trial than at the start, whereas the glucose response remained similar. The SF calves, however, showed pronounced hyperglycemia and hyperinsulinemia at the end of the trial, although weaning did not affect insulin sensitivity. We conclude that whole body insulin sensitivity decreases by 75% in calves during the first 3 mo of life. Weaning or supplementation of short-chain FOS does not affect this age-related decline in insulin sensitivity. Glucose homeostasis is not affected by supplementation of short-chain FOS in young calves, whereas postprandial responses of glucose and insulin to a MR meal strongly increase after weaning.
Redirection of auxin flow in Arabidopsis thaliana roots after infection by root-knot nematodes
Kyndt, Tina ; Goverse, Aska ; Haegeman, Annelies ; Warmerdam, Sonja ; Wanjau, Cecilia ; Jahani, Mona ; Engler, Gilbert ; Almeida Engler, Janice De; Gheysen, Godelieve - \ 2016
Journal of Experimental Botany 67 (2016)15. - ISSN 0022-0957 - p. 4559 - 4570.
Plant-parasitic root-knot nematodes induce the formation of giant cells within the plant root, and it has been recognized that auxin accumulates in these feeding sites. Here, we studied the role of the auxin transport system governed by AUX1/LAX3 influx proteins and different PIN efflux proteins during feeding site development in Arabidopsis thaliana roots. Data generated via promoter–reporter line and protein localization analyses evoke a model in which auxin is being imported at the basipetal side of the feeding site by the concerted action of the influx proteins AUX1 and LAX3, and the efflux protein PIN3. Mutants in auxin influx proteins AUX1 and LAX3 bear significantly fewer and smaller galls, revealing that auxin import into the feeding sites is needed for their development and expansion. The feeding site development in auxin export (PIN) mutants was only slightly hampered. Expression of some PINs appears to be suppressed in galls, probably to prevent auxin drainage. Nevertheless, a functional PIN4 gene seems to be a prerequisite for proper nematode development and gall expansion, most likely by removing excessive auxin to stabilize the hormone level in the feeding site. Our data also indicate a role of local auxin peaks in nematode attraction towards the root
The effect of replacing lactose by starch on protein and fat digestion in milk-fed veal calves
Pluschke, A.M. ; Gilbert, M.S. ; Williams, B.A. ; Borne, J.J.G.C. van den; Schols, H.A. ; Gerrits, W.J.J. - \ 2016
Animal 10 (2016)8. - ISSN 1751-7311 - p. 1296 - 1302.
lipase - milk-fed calf - starch - trypsin - α-amylase

Replacing dairy components from milk replacer (MR) with vegetable products has been previously associated with decreased protein and fat digestibility in milk-fed calves resulting in lower live weight gain. In this experiment, the major carbohydrate source in MR, lactose, was partly replaced with gelatinized corn starch (GCS) to determine the effect on protein and fat digestibility in milk-fed calves. In total, 16 male Holstein-Friesian calves received either MR with lactose as the carbohydrate source (control) or 18% GCS at the expense of lactose. In the adaptation period, calves were exposed to an increasing dose of GCS for 14 weeks. The indigestible marker cobalt ethylenediaminetetraacetic acid was incorporated into the MR for calculating apparent nutrient digestibility, whereas a pulse dose of chromium (Cr) chloride was fed with the last MR meal 4 h before slaughter as an indicator of passage rates. The calves were anesthetized and exsanguinated at 30 weeks of age. The small intestine was divided in three; small intestine 1 and 2 (SI1 and SI2, respectively) and the terminal ileum (last ~100 cm of small intestine) and samples of digesta were collected. Small intestinal digesta was analysed for α-amylase, lipase and trypsin activity. Digestibility of protein was determined for SI1, SI2, ileum and total tract, whereas digestibility of fat was determined for SI1, SI2 and total tract. Apparent protein digestibility in the small intestine did not differ between treatments but was higher in control calves at total tract level. Apparent crude fat digestibility tended to be increased in SI1 and SI2 for GCS calves, but no difference was found at total tract level. Activity of α-amylase in SI2 and lipase in both SI1 and SI2 was higher in GCS calves. Activity of trypsin tended to be higher in control calves and was higher in SI1 compared with SI2. A lower recovery of Cr in SI2 and a higher recovery of Cr in the large intestine suggest an increased rate of passage for GCS calves. Including 18% of GCS in a milk replacer at the expense of lactose increased passage rate and decreased apparent total tract protein digestibility. In the small intestine, protein digestion did not decrease when feeding GCS and fat digestion even tended to increase. Overall, effects on digestion might be levelled when partially replacing lactose with GCS, because starch digestion is lower than that of lactose but fat digestion may be slightly increased when feeding GCS.

Lactose in milk replacer can partly be replaced by glucose, fructose, or glycerol without affecting insulin sensitivity in veal calves
Pantophlet, A.J. ; Gilbert, M.S. ; Borne, J.J.G.C. van den; Gerrits, W.J.J. ; Roelofsen, H. ; Priebe, M.G. ; Vonk, R.J. - \ 2016
Journal of Dairy Science 99 (2016)4. - ISSN 0022-0302 - p. 3072 - 3080.
Fructose - Glucose homeostasis - Glycerol - Insulin sensitivity - Veal calves

Calf milk replacer (MR) contains 40 to 50% lactose. Lactose strongly fluctuates in price and alternatives are desired. Also, problems with glucose homeostasis and insulin sensitivity (i.e., high incidence of hyperglycemia and hyperinsulinemia) have been described for heavy veal calves (body weight >100 kg). Replacement of lactose by other dietary substrates can be economically attractive, and may also positively (or negatively) affect the risk of developing problems with glucose metabolism. An experiment was designed to study the effects of replacing one third of the dietary lactose by glucose, fructose, or glycerol on glucose homeostasis and insulin sensitivity in veal calves. Forty male Holstein-Friesian (body weight = 114 ± 2.4 kg; age = 97 ± 1.4 d) calves were fed an MR containing 462 g of lactose/kg (CON), or an MR in which 150 g of lactose/kg of MR was replaced by glucose (GLU), fructose (FRU), or glycerol (GLY). During the first 10 d of the trial, all calves received CON. The CON group remained on this diet and the other groups received their experimental diets for a period of 8 wk. Measurements were conducted during the first (baseline) and last week of the trial. A frequently sampled intravenous glucose tolerance test was performed to assess insulin sensitivity and 24 h of urine was collected to measure glucose excretion. During the last week of the trial, a bolus of 1.5 g of [U-13C] substrates was added to their respective meals and plasma glucose, insulin, and 13C-glucose responses were measured. Insulin sensitivity was low at the start of the trial and remained low [1.2 ± 0.1 and 1.0 ± 0.1 (mU/L)-1 × min-1], and no treatment effect was noted. Glucose excretion was low at the start of the trial (3.4 ± 1.0 g/d), but increased (P <0.01) in CON and GLU calves (26.9 ± 3.9 and 43.0 ± 10.6 g/d) but not in FRU and GLY calves. Postprandial glucose was higher in GLU, lower in FRU, and similar in GLY compared with CON calves. Postprandial insulin was lower in FRU and GLY and similar in GLU compared with CON calves. Postprandial 13C-glucose increased substantially in FRU and GLY calves, indicating that calves are able to partially convert these substrates to glucose. We concluded that replacing one third of lactose in MR by glucose, fructose, or glycerol in MR differentially influences postprandial glucose homeostasis but does not affect insulin sensitivity in veal calves.

Effects of replacing lactose from milk replacer by glucose, fructose, or glycerol on energy partitioning in veal calves
Gilbert, M.S. ; Pantophlet, A.J. ; Borne, J.J.G.C. van den; Hendriks, W.H. ; Schols, H.A. ; Gerrits, W.J.J. - \ 2016
Journal of Dairy Science 99 (2016)2. - ISSN 0022-0302 - p. 1121 - 1132.
Energy retention - Fructose - Glucose - Glycerol - Veal calf

Calf milk replacers contain 40 to 50% lactose. Fluctuating dairy prices are a major economic incentive to replace lactose from milk replacers by alternative energy sources. Our objective was, therefore, to determine the effects of replacement of lactose with glucose, fructose, or glycerol on energy and protein metabolism in veal calves. Forty male Holstein-Friesian calves (114 ± 2.4 kg) were fed milk replacer containing 46% lactose (CON) or 31% lactose and 15% of glucose (GLUC), fructose (FRUC), or glycerol (GLYC). Solid feed was provided at 10 g of dry matter (DM)/kg of metabolic body weight (BW0.75) per day. After an adaptation of 48 d, individual calves were harnessed, placed in metabolic cages, and housed in pairs in respiration chambers. Apparent total-tract disappearance of DM, energy, and N and complete energy and N balances were measured. The GLUC, FRUC, and GLYC calves received a single dose of 1.5 g of [U-13C]glucose, [U-13C]fructose, or [U-13C]glycerol, respectively, with their milk replacer at 0630 h and exhaled 13CO2 and 13C excretion with feces was measured. Apparent total-tract disappearance was decreased by 2.2% for DM, 3.2% for energy, and 4.2% for N in FRUC compared with CON calves. Energy and N retention did not differ between treatments, and averaged 299 ± 16 kJ/kg of BW0.75 per day and 0.79 ± 0.04 g/kg of BW0.75 per day, respectively, although FRUC calves retained numerically less N (13%) than other calves. Recovery of 13C isotopes as 13CO2 did not differ between treatments and averaged 72 ± 1.6%. The time at which the maximum rate of 13CO2 production was reached was more than 3 h delayed for FRUC calves, which may be explained by a conversion of fructose into other substrates before being oxidized. Recovery of 13C in feces was greater for FRUC calves (7.7 ± 0.59%) than for GLUC (1.0 ± 0.27%) and GLYC calves (0.5 ± 0.04%), indicating incomplete absorption of fructose from the small intestine resulting in fructose excretion or fermentation. In conclusion, energy and N retention was not affected when replacing >30% of the lactose with glucose, fructose, or glycerol. Increased fecal losses of DM, energy, and N were found in FRUC calves compared with CON, GLUC, and GLYC calves. Postabsorptive losses occurred with the urine for glucose and glycerol, which caused a lower respiratory quotient for GLUC calves during the night. Fructose was oxidized more slowly than glucose and glycerol, probably as a result of conversion into other substrates before oxidation.

Whole Genome PCR Scanning (WGPS) of C. burnetii strains from ruminants
Sidi-Boumedine, Karim ; Adam, Gilbert ; Angen, Oysten ; Aspán, A. ; Bossers, A. ; Roest, H.I.J. ; Prigent, Myriam ; Thiéry, R. ; Rousset, Elodie - \ 2015
Microbes and Infection 17 (2015)11-12. - ISSN 1286-4579 - p. 772 - 775.
Coxiella burnetii is the causative agent of Q fever, a zoonosis that spreads from ruminants to humans via the inhalation of aerosols contaminated by livestock's birth products. This study aimed to compare the genomes of strains isolated from ruminants by “Whole Genome PCR Scanning (WGPS)” in order to identify genomic differences. C. burnetii isolated from different ruminant hosts were compared to the Nine Mile reference strain using WGPS. The identified genomic regions of differences (RDs) were confirmed by sequencing. A set of 219 primers for amplification of 10 kbp segments covering the entire genome was obtained. The analyses revealed the presence of: i) conserved genomic regions, ii) genomic polymorphism including insertions and deletions and iii) amplification failures in some cases as well. WGPS, a descriptive approach, allowed the identification and localization of divergent genetic loci from various strains of C. burnetii which consisted of deletions, insertions and maybe genomic rearrangements. It also substantiates the role played by the IS1111 element in the genomic plasticity of C. burnetii. We believe that this approach could be combined with new sequencing technologies, as a selective/directed sequencing approach, particularly when repeated sequences are present in the analysed genomes
Campylobacter iguaniorum sp. nov., isolated from reptiles
Gilbert, Maarten J. ; Kik, Marja ; Miller, William G. ; Duim, Birgitta ; Wagenaar, Jaap A. - \ 2015
International Journal of Systematic and Evolutionary Microbiology 65 (2015)3. - ISSN 1466-5026 - p. 975 - 982.

During sampling of reptiles for members of the class Epsilonproteobacteria, strains representing a member of the genus Campylobacter not belonging to any of the established taxa were isolated from lizards and chelonians. Initial amplified fragment length polymorphism, PCR and 16S rRNA sequence analysis showed that these strains were most closely related to Campylobacter fetus and Campylobacter hyointestinalis. A polyphasic study was undertaken to determine the taxonomic position of five strains. The strains were characterized by 16S rRNA and atpA sequence analysis, matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry and conventional phenotypic testing. Whole-genome sequences were determined for strains 1485ET and 2463D, and the average nucleotide and amino acid identities were determined for these strains. The strains formed a robust phylogenetic clade, divergent from all other species of the genus Campylobacter. In contrast to most currently known members of the genus Campylobacter, the strains showed growth at ambient temperatures, which might be an adaptation to their reptilian hosts. The results of this study clearly show that these strains isolated from reptiles represent a novel species within the genus Campylobacter, for which the name Campylobacter iguaniorum sp. nov. is proposed. The type strain is 1485ET (=LMG 28143T=CCUG 66346T).

Replacing lactose from calf milk replacers : effects on digestion and post-absorptive metabolism
Gilbert, M.S. - \ 2015
Wageningen University. Promotor(en): Wouter Hendriks, co-promotor(en): Walter Gerrits; Henk Schols. - Wageningen : Wageningen University - ISBN 9789462576032 - 171
vleeskalveren - lactose - kunstmelk - polysacchariden - glucose - fructose - glycerol - zetmeelvertering - metabolisme - fermentatie - kalvervoeding - diervoeding - voedingsfysiologie - veal calves - lactose - filled milk - polysaccharides - glucose - fructose - glycerol - starch digestion - metabolism - fermentation - calf feeding - animal nutrition - nutrition physiology

Summary PhD thesis Myrthe S. Gilbert

Replacing lactose from calf milk replacers – Effects on digestion and post-absorptive metabolism

Veal calves are fed milk replacer (MR) and solid feed. The largest part of the energy provided to veal calves originates from the MR. Calf MR contains 40 to 50% lactose, originating from whey, a by-product from cheese production. High and strongly fluctuating dairy prices are a major economic incentive to replace lactose from the calf MR by alternative energy sources. The objective of this thesis was to study the effects of replacing lactose from calf MR on nutrient digestion and fermentation and post-absorptive metabolism.

In Chapter 2 and 3, four starch products (SP) were evaluated for replacing lactose. The four SP differed in size and branching, and consequently required different ratios of starch-degrading enzymes for their complete hydrolysis to glucose. Gelatinized starch required α-amylase and (iso)maltase; maltodextrin required (iso)maltase and α-amylase; maltodextrin with α-1,6-branching required isomaltase, maltase and α-amylase and maltose required maltase. In Chapter 2, adaptation to these SP was assessed during 14 weeks, using a within-animal titration study. Forty male Holstein-Friesian calves (n = 8 per treatment) were assigned to either a lactose control MR or one of four titration strategies, each testing the stepwise exchange of lactose for one of the SP. For control calves, fecal dry matter (DM) content and fecal pH did not change over time. The response in fecal DM content and fecal pH in time did not differ between SP treatments and decreased linearly with 0.57% and 0.32 per week, respectively, where one week corresponded to an increase in SP inclusion of 3%. This indicates that the capacity for starch digestion was already exceeded at low inclusion levels, resulting in SP fermentation. All SP required maltase to achieve complete hydrolysis to glucose and it was, therefore, suggested that maltase is the rate-limiting enzyme in starch digestion in milk-fed calves.

Following the titration, a fixed inclusion level of 18% of the SP in the MR was applied. Effects on starch-degrading enzyme activity, nutrient disappearance, SP fermentation and jugular glucose appearance were measured (Chapter 3). Lactase activity in the brush border was high in the proximal small intestine of all calves, resulting in a high apparent ileal disappearance of lactose (≥ 99% of intake). Maltase and isomaltase activities in the brush border were not increased for any of the SP treatments. Luminal α-amylase activity was lower in the proximal small intestine but greater in the distal small intestine of SP-fed calves compared to control calves. This amylase activity in the distal small intestine of SP-fed calves might have been of microbial origin. Apparent SP disappearance did not differ between SP treatments. The difference between apparent ileal (62%) and total tract (99%) SP disappearance indicated substantial SP fermentation in the large intestine (37% of intake). In addition, total tract SP fermentation was quantified using fecal 13C excretion which originated from the naturally 13C-enriched corn SP. Total tract SP fermentation averaged 89% of intake, regardless of SP treatment. MR leaking into the reticulorumen was measured as the recovery of Cr in the reticulorumen at slaughter after feeding MR pulse-dosed with Cr 4h prior to slaughter. MR leaking into the reticulorumen averaged 11% for SP-fed calves. By difference, this leaves 41% of the SP intake fermented in the small intestine. This coincided with increased fecal nitrogen (N) and DM losses for SP-fed calves. However, apparent total tract crude fat disappearance tended to increase when replacing lactose with SP. The substantial SP fermentation indicates that only 10% of the SP intake was enzymatically hydrolyzed and absorbed as glucose. This was in agreement with the marginal increase in 13C enrichment in peripheral plasma glucose after feeding naturally 13C-enriched gelatinized starch and maltose, compared to a clear increase after feeding naturally 13C-enriched lactose to control calves. It was concluded that fermentation, rather than enzymatic digestion, is the main reason for small intestinal starch disappearance in milk-fed calves. The expected decrease in growth performance with such extensive SP fermentation is partially compensated by the greater crude fat digestion and possibly by a reduced urinary glucose excretion when replacing lactose with SP.

Glucose, fructose and glycerol do not require enzymatic hydrolysis and can be absorbed directly from the small intestine. However, these lactose replacers might differentially affect glucose and insulin metabolism and with that energy partitioning. The effects of partly replacing lactose with glucose, fructose or glycerol on energy and N partitioning and glucose homeostasis and insulin sensitivity were, therefore, studied in Chapter 4 and 5. Forty male Holstein-Friesian calves either received a lactose control MR or a MR in which one third of the lactose was replaced with glucose, fructose or glycerol (n = 10 per treatment). Energy and N retention were not affected by MR composition. Fructose absorption from the small intestine was incomplete resulting in fructose fermentation. This resulted in fecal losses of DM, energy and N and the lowest numerical energy and N retention for fructose-fed calves. Postprandial plasma concentrations of glucose exceeded the renal threshold for glucose in glucose-fed calves and control calves, which resulted in urinary glucose excretion. Glycerol was likely excreted with the urine of glycerol-fed calves. Oxidation of glucose, fructose and glycerol was quantified by feeding a single dose of [U-13C]glucose, [U-13C]fructose or [U-13C]glycerol with the MR and subsequently measuring 13CO2 production. Oxidation of lactose replacers did not differ between lactose replacers and averaged 72% of intake. However, the time at which the maximum rate of oxidation was reached was delayed for fructose-fed compared to glucose-fed and glycerol-fed calves, indicating that fructose was converted into other substrates before being oxidized. Conversion of fructose and glycerol into glucose was confirmed by an increase in 13C enrichment of peripheral plasma glucose after feeding [U-13C]fructose and [U-13C]glycerol, respectively. Insulin sensitivity did not differ between MR treatments, but was already low at the start of the experiment at 15 weeks of age and remained low throughout the experiment. It was concluded that glucose and glycerol can replace one third of the lactose from the calf MR, but that inclusion of fructose should be lower to prevent incomplete absorption from the small intestine.

In literature and the studies in this thesis, high inter-individual variation in growth performance was found in veal calves. The experiment described in Chapter 6 was, therefore, designed to assess the predictability of later life growth performance by charactering calves in early life. In addition, it was examined whether the ability of calves to cope with MR in which lactose is partially replaced by alternative energy sources can be predicted. From 2 to 11 weeks of age, male Holstein-Friesian calves were fed a lactose control MR and solid feed according to a practical feeding scheme and were characterized individually using targeted challenges related to feeding motivation, digestion, post-absorptive metabolism, immunology, behavior and stress. Based on the results in Chapter 4, a combination of glucose, fructose and glycerol in a 2:1:2 ratio was used to replace half of the lactose from the MR (GFG). From 11 to 27 weeks of age, calves received a lactose control MR or the GFG MR (n = 65 per treatment). Growth performance from 11 to 27 weeks of age tended to be lower for GFG-fed than for control calves (-25 g/d). Measurements in early life explained 12% of the variation in growth performance in later life. However, this was mainly related to variation in solid feed refusals. When growth performance was adjusted to equal solid feed intake, only 4% of the variation in standardized growth performance in later life, reflecting feed efficiency, could be explained by early life measurements. This indicates that > 95% of the variation in feed efficiency in later life could not be explained by early life characterization. It is hypothesized that variation in health status explains substantial variation in feed efficiency in veal calves. Significant relations between fasting plasma glucose concentrations, fecal dry matter and fecal pH in early life and feed efficiency in later life depended on MR composition. These measurements are, therefore, potential tools for screening calves in early life on their ability to cope with a MR in which half of the lactose is replaced by glucose, fructose and glycerol (in a 2:1:2 ratio).

The studies reported in this thesis demonstrate that glycerol, glucose and a combination of glucose, fructose and glycerol in a 2:1:2 ratio are promising lactose replacers. The effects of replacing lactose by other carbohydrate or energy sources described in this thesis are required to evaluate the potential of lactose replacers for inclusion in calf milk replacers and provide input for feed evaluation for calves and ruminants.

Fermentation in the small intestine contributes substantially to intestinal starch disappearance in calves
Gilbert, M.S. ; Pantophlet, A.J. ; Berends, H. ; Pluschke, A.M. ; Borne, J.J.G.C. van den; Hendriks, W.H. ; Schols, H.A. ; Gerrits, W.J.J. - \ 2015
The Journal of Nutrition 145 (2015)6. - ISSN 0022-3166 - p. 1147 - 1155.
Background: The proportion of starch disappearing from the small intestinal lumen is generally lower in ruminants than in monogastric animals, and there are indications that the starch digestion capacity in ruminants is limited. Objectives: Milk-fed calves were used to study the rate-limiting enzyme in starch hydrolysis and to quantify starch fermentation in ruminants. Methods: Forty male Holstein-Friesian calves were fed milk replacer containing either lactose (control) or 1 of 4 corn starch products. The following starch products differed in the enzyme ratios required for their complete hydrolysis to glucose: gelatinized starch [a-amylase and (iso)maltase], maltodextrin [(iso)maltase and a-amylase], maltodextrin with a-1,6-branching (isomaltase, maltase, and a-amylase), and maltose (maltase). In the adaptation period, calves were stepwise exposed to an increasing dose of the starch product for 14 wk to allow maximal adaptation of all enzyme systems involved. In the experimental period, apparent total tract and ileal starch product disappearance, total tract starch product fermentation, and a-amylase, maltase, and isomaltase activities were determined at 18% inclusion of the starch product. Results: Maltase and isomaltase activities in the brush border did not increase for any of the starch product treatments. Luminal a-amylase activity was lower in the proximal (3.9 ± 3.2 and 2.7 ± 1.7 U/mg Co for control and starch product calves, respectively) but greater in the distal small intestine of starch-fed calves than in control calves (0.0 ± 0.0 and 6.4 ± 1.5 U/mg Co for control and starch product calves, respectively; means ± SEs for control and means ± pooled SEMs for starch product treatments). Apparent ileal (61.6% ± 6.3%) and total tract (99.1% ± 0.4%) starch product disappearance did not differ between starch product treatments, suggesting that maltase activity limits starch digestion in ruminants. Total tract starch product fermentation averaged 414 ± 43 g/d, corresponding to 89% of intake, of which half was fermented before the terminal ileum, regardless of starch product treatment. Conclusion: Fermentation, rather than enzymatic digestion, is the main reason for small intestinal starch disappearance in milk-fed calves.
Effects of solid feed level and roughage-to-concentrate ratio on ruminal drinking and passage kinetics of milk replacer, concentrates, and roughage in veal calves
Berends, H. ; Borne, J.J.G.C. van den; Stockhofe-Zurwieden, N. ; Gilbert, M.S. ; Zandstra, T. ; Pellikaan, W.F. ; Reenen, C.G. van; Bokkers, E.A.M. ; Gerrits, W.J.J. - \ 2015
Journal of Dairy Science 98 (2015)8. - ISSN 0022-0302 - p. 5621 - 5629.
Effects of solid feed (SF) level and roughage-to-concentrate (R:C) ratio on ruminal drinking and passage kinetics of milk replacer, concentrate, and roughage were studied in veal calves. In total, 80 male Holstein-Friesian calves (45 ± 0.2 kg of body weight) were divided over 16 pens (5 calves per pen). Pens were randomly assigned to either a low (LSF) or a high (HSF) SF level and to 1 of 2 R:C ratios: 20:80 or 50:50 on a dry matter (DM) basis. Roughage was composed of 50% corn silage and 50% chopped wheat straw on a DM basis. At 27 wk of age, measurements were conducted in 32 calves. During the measurement period, SF intake was 1.2 kg of DM/d for LSF and 3.0 kg of DM/d for HSF, and milk replacer intake averaged 2.3 kg of DM/d for LSF and 1.3 kg of DM/d for HSF. To estimate passage kinetics of milk replacer, concentrate, and straw, indigestible markers (CoEDTA, hexatriacontane C36, Cr-neutral detergent fiber) were supplied with the feed as a single dose 4, 24, and 48 h before assessment of their quantitative recovery in the rumen, abomasum, small intestine, and large intestine. Rumen Co recovery averaged 20% of the last milk replacer meal. Recoveries of Co remained largely unaffected by SF level and R:C ratio. The R:C ratio did not affect rumen recovery of C36 or Cr. Rumen fractional passage rate of concentrate was estimated from recovery of C36 in the rumen and increased from 3.3%/h for LSF to 4.9%/h for HSF. Rumen fractional passage rate of straw was estimated from Cr recovery in the rumen and increased from 1.3%/h for LSF to 1.7%/h for HSF. An increase in SF level was accompanied by an increase in fresh and dry rumen contents. In HSF calves, pH decreased and VFA concentrations increased with increasing concentrate proportion, indicating increased fermentation. The ratio between Cr and C36 was similar in the small and large intestine, indicating that passage of concentrate and straw is mainly determined by rumen and abomasum emptying. In conclusion, increasing SF level introduces large variation in passage kinetics of dietary components, predominantly in the rumen compartment. The SF level, rather than the R:C ratio, influences rumen recovery of concentrate and roughage. Our data provide insight in passage kinetics of milk (Co representing the milk replacer) and SF (Cr and C36 representing roughage and concentrate, respectively) and may contribute to the development of feed evaluation models for calves fed milk and SF.
Downstream processing of Isochrysis galbana: a step towards microalgal biorefinery
Gilbert-López, B. ; Mendiola, J.A. ; Fontecha, J. ; Broek, L.A.M. van den; Sijtsma, L. ; Cifuentes, A. ; Herrero, M. ; Ibáñez, E. - \ 2015
Green Chemistry 17 (2015)9. - ISSN 1463-9262 - p. 4599 - 4609.
An algae-based biorefinery relies on the efficient use of algae biomass through its fractionation of several valuable/bioactive compounds that can be used in industry. If this biorefinery includes green platforms as downstream processing technologies able to fulfill the requirements of green chemistry, it will end-up with sustainable processes. In the present study, a downstream processing platform has been developed to extract bioactive compounds from the microalga Isochrysis galbana using various pressurized green solvents. Extractions were performed in four sequential steps using (1) supercritical CO2 (ScCO2), (2) ScCO2/ethanol (Gas Expanded Liquid, GXL), (3) pure ethanol, and (4) pure water as solvents, respectively. The residue of the extraction step was used as the raw material for the next extraction. Optimization of the ScCO2 extraction was performed by factorial design in order to maximize carotenoid extraction. During the second step, different percentages of ethanol were evaluated (15%, 45% and 75%) in order to maximize the extraction yield of fucoxanthin, the main carotenoid present in this alga; the extraction of polar lipids was also an aim. The third and fourth steps were performed with the objective of recovering fractions with high antioxidant activity, eventually rich in carbohydrates and proteins. The green downstream platform developed in this study produced different extracts with potential for application in the food, pharmaceutical and cosmetic industries. Therefore, a good approach for complete revalorization of the microalgae biomass is proposed, by using processes complying with the green chemistry principles.
Effects of solid feed level and roughage-to-concentrate ratio on ruminal drinking and passage kinetics of milk, concentrates, and roughage in veal calves
Berends, H. ; Borne, J.J.G.C. van den; Stockhofe, N. ; Gilbert, M.S. ; Zandstra, T. ; Pellikaan, W.F. ; Reenen, K. van; Bokkers, E.A.M. ; Gerrits, W.J.J. - \ 2015
In: Book of abstracts of 2015 Joint Annual Meeting of ADSA-ASAS. - - p. 869 - 869.
Effects of solid feed (SF) level and roughage-to-concentrate (R:C) ratio on ruminal drinking and passage kinetics of milk, concentrate, and roughage in veal calves were studied. Eighty calves (2 wk of age, 45 kg bodyweight) were divided over 16 pens. Pens were randomly assigned to a low (LSF) or a high (HSF) SF level, and to one of 2 R:C ratios; 20:80 or 50:50 on a DM basis. Roughage was composed of 50% corn silage and 50% chopped straw on a DM basis. During the measurement period at 27 wk of age, SF intake was 1.2 kg DM/d for LSF and 3.0 kg DM/d for HSF, and milk (replacer) intake averaged 2.3 kg DM/d for LSF and 1.3 kg DM/d for HSF. To estimate passage kinetics of milk, concentrate, and straw, indigestible markers (respectively CoEDTA, hexatriacontane C36, Cr-NDF) were supplied with the feed as a single dose at respectively 4, 24, and 48 h before slaughter. At slaughter, marker recovery was quantified in the rumen, abomasum, small intestine, and large intestine. Rumen Co recovery averaged 20% of the last milk meal. Recoveries of milk remained largely unaffected by SF level and R:C ratio. Ruminal recovery of C36 and Cr was unaffected by R:C ratio. Rumen fractional passage rate of concentrate was estimated from recovery of C36 in the rumen and increased (P <0.001) from 3.3%/h for LSF to 4.9%/h for HSF. Rumen fractional passage rate of straw was estimated from Cr recovery in the rumen and increased (P <0.01) from 1.3%/h for LSF to 1.7%/h for HSF. A greater SF level increased (P <0.001) fresh and dry rumen contents. In HSF calves, pH decreased (from 6.9 to 6.0; P <0.01) and VFA concentrations increased (P <0.05) with a lower R:C ratio, indicating increased fermentation. The Cr:C36 ratio was similar in the small and large intestine, indicating that passage of concentrate and straw was mainly determined by rumen and abomasum emptying. In conclusion, SF level rather than R:C ratio influences rumen passage of concentrate and roughage. Our data provide insight in passage kinetics of milk and SF and may contribute to the development of feed evaluation models for veal calves
Alterra en de kunst van het kronkelen
Kleis, R. ; Makaske, A. ; Maas, H.A. - \ 2015
Resource: weekblad voor Wageningen UR 10 (2015)1. - ISSN 1874-3625 - p. 9 - 9.
waterlopen - herstelbeheer - geomorfologie - natuurlandschap - ecologisch herstel - waterstroming - waterbeheer - streams - restoration management - geomorphology - natural landscape - ecological restoration - water flow - water management
Een groot deel van onze beken heeft op dit moment een verre van natuurlijk verloop. Om wateroverlast tegen te gaan zijn in de vorige eeuw veel van oudsher kronkelige beken rechtgetrokken. Rechte beken voeren het water sneller af. Maar tegenwoordig is dat niet meer gewenst. Die snelle afvoer leidt tot verdroging en rechtgetrokken beken bieden weinig kansen voor een diversiteit in flora en fauna. Met beekherstel probeert men dat tij te keren. Bart Makaske en Gilbert Maas van Alterra schreven een boek over hoe je beken het beste laat kronkelen.
Organogel formation via supramolecular assembly of oleic acid and sodium oleate
Nikiforidis, C.V. ; Gilbert, E.P. ; Scholten, E. - \ 2015
RSC Advances : An international journal to further the chemical sciences 5 (2015)59. - ISSN 2046-2069 - p. 47466 - 47475.
system - solvent - liquid - amphiphiles - particles - micelles - lecithin - bilayers - laurate - water
To create materials with novel functionalities, the formation of gels within hydrophobic media has become popular. This is often accomplished through the assembly of low molecular weight organogelators into a variety of complex phases through intermolecular interactions. In the case of edible materials, the assembly of saturated fatty acids to form fat crystal networks is often used for structuring. Here, the first example of structuring with unsaturated fatty acids is reported, namely mixtures of oleic acid and sodium oleate, to structure edible lipid phases. Small-angle scattering demonstrates that the resultant structures, which vary with oleic acid and sodium oleate molar ratio, comprise either inverse micellar or lamellar phases, combined with the formation of crystalline space-filling networks. Network formation was found for filler concentrations above 10 wt%. Rheological measurements show that gel strength depends on the ratio of oleic acid to sodium oleate, and is greater when only oleic acid is used. The addition of up to 1.5 wt% of water enhanced the strength of the organogels, probably through supplementary hydrogen bonding but, for concentrations greater than 2.0 wt%, the assembly was inhibited leading to collapse of the gel.
Landschappelijke bodemkaart: sleutel op het BIS
Maas, Gilbert - \ 2015
Whole-grain wheat consumption reduces inflammation in a randomized controlled trial on overweight and obese subjects with unhealthy dietary and lifestyle behaviors: role of polyphenols bound to cereal dietary fiber
Vitaglione, P. ; Mennella, I. ; Ferracane, R. ; Rivellese, A.A. ; Giacco, R. ; Ercolini, D. ; Gibbons, S.M. ; Storia, A. la; Gilbert, A.J. ; Jonnalagadda, S. ; Thielecke, F. ; Gallo, M.A. ; Scalfi, L. ; Fogliano, V. - \ 2015
American Journal of Clinical Nutrition 101 (2015)2. - ISSN 0002-9165 - p. 251 - 261.
Background: Epidemiology associates whole-grain (WG) consumption with several health benefits. Mounting evidence suggests that WG wheat polyphenols play a role in mechanisms underlying health benefits. Objective: The objective was to assess circulating concentration, excretion, and the physiologic role of WG wheat polyphenols in subjects with suboptimal dietary and lifestyle behaviors. Design: A placebo-controlled, parallel-group randomized trial with 80 healthy overweight/obese subjects with low intake of fruits and vegetables and sedentary lifestyle was performed. Participants replaced precise portions of refined wheat (RW) with a fixed amount of selected WG wheat or RW products for 8 wk. At baseline and every 4 wk, blood, urine, feces, and anthropometric and body composition measures were collected. Profiles of phenolic acids in biological samples, plasma markers of metabolic disease and inflammation, and fecal microbiota composition were assessed. Results: WG consumption for 4–8 wk determined a 4-fold increase of serum dihydroferulic acid (DHFA) and a 2-fold increase of fecal ferulic acid (FA) compared with RW consumption (no changes). Similarly, urinary FA at 8 wk doubled the baseline concentration only in WG subjects. Concomitant reduction of plasma tumor necrosis factor-a (TNF-a) after 8 wk and increased interleukin (IL)-10 only after 4 wk with WG compared with RW (P = 0.04) were observed. No significant change in plasma metabolic disease markers over the study period was observed, but a trend toward lower plasma plasminogen activator inhibitor 1 with higher excretion of FA and DHFA in the WG group was found. Fecal FA was associated with baseline low Bifidobacteriales and Bacteroidetes abundances, whereas after WG consumption, it correlated with increased Bacteroidetes and Firmicutes but reduced Clostridium. TNF-a reduction correlated with increased Bacteroides and Lactobacillus. No effect of dietary interventions on anthropometry and body composition was found. Conclusions: WG wheat consumption significantly increased excreted FA and circulating DHFA. Bacterial communities influenced fecal FA and were modified by WG wheat consumption.
A titration approach to identify the capacity for starch digeston in milk-fed calves
Gilbert, M.S. ; Borne, J.J.G.C. van den; Berends, H. ; Pantophlet, A.J. ; Schols, H.A. ; Gerrits, W.J.J. - \ 2015
Animal 9 (2015)2. - ISSN 1751-7311 - p. 249 - 257.
small-intestinal disappearance - abomasal glucose - maize starch - amylase - steers - oligosaccharide - digestibility - secretion - replacers - infusion
Calf milk replacers (MR) commonly contain 40% to 50% lactose. For economic reasons, starch is of interest as a lactose replacer. Compared with lactose, starch digestion is generally low in calves. It is, however, unknown which enzyme limits the rate of starch digestion. The objectives were to determine which enzyme limits starch digestion and to assess the maximum capacity for starch digestion in milk-fed calves. A within-animal titration study was performed, where lactose was exchanged stepwise for one of four starch products (SP). The four corn-based SP differed in size and branching, therefore requiring different ratios of starch-degrading enzymes for their complete hydrolysis to glucose: gelatinised starch (a-amylase and (iso)maltase); maltodextrin ((iso)maltase and a-amylase); maltodextrin with a-1,6-branching (isomaltase, maltase and a-amylase) and maltose (maltase). When exceeding the animal’s capacity to enzymatically hydrolyse starch, fermentation occurs, leading to a reduced faecal dry matter (DM) content and pH. Forty calves (13 weeks of age) were assigned to either a lactose control diet or one of four titration strategies (n=8 per treatment), each testing the stepwise exchange of lactose for one SP. Dietary inclusion of each SP was increased weekly by 3% at the expense of lactose and faecal samples were collected from the rectum weekly to determine DM content and pH. The increase in SP inclusion was stopped when faecal DM content dropped below 10.6% (i.e. 75% of the average initial faecal DM content) for 3 consecutive weeks. For control calves, faecal DM content and pH did not change over time. For 87% of the SP-fed calves, faecal DM and pH decreased already at low inclusion levels, and linear regression provided a better fit of the data (faecal DM content or pH v. time) than non-linear regression. For all SP treatments, faecal DM content and pH decreased in time (P
Campylobacter fetus subsp. testudinum subsp. nov., isolated from humans and reptiles
Fitzgerald, C. ; Tu, Z.C. ; Patrick, M. ; Stiles, T. ; Lawson, A.J. ; Santovenia, M. ; Gilbert, M.J. ; Bergen, M. von; Joyce, K. ; Pruckler, J. ; Stroika, S. ; Duim, B. ; Miller, W.G. ; Loparev, V. ; Sinnige, J.C. ; Fields, P.I. ; Tauxe, R.V. ; Blaser, M.J. ; Wagenaar, J.A. - \ 2014
International Journal of Systematic and Evolutionary Microbiology 64 (2014). - ISSN 1466-5026 - p. 2944 - 2948.
genus campylobacter - pcr assay - differentiation - identification - strains - origins
A polyphasic study was undertaken to determine the taxonomic position of 13 Campylobacter fetus-like strains from humans (n=8) and reptiles (n=5). The results of matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) MS and genomic data from sap analysis, 16S rRNA gene and hsp60 sequence comparison, pulsed-field gel electrophoresis, amplified fragment length polymorphism analysis, DNA-DNA hybridization and whole genome sequencing demonstrated that these strains are closely related to C. fetus but clearly differentiated from recognized subspecies of C. fetus. Therefore, this unique cluster of 13 strains represents a novel subspecies within the species C. fetus, for which the name Campylobacter fetus subsp. testudinum subsp. nov. is proposed, with strain 03-427(T) (=ATCC BAA-2539(T)=LMG 27499(T)) as the type strain. Although this novel taxon could not be differentiated from C. fetus subsp. fetus and C. fetus subsp. venerealis using conventional phenotypic tests, MALDI-TOF MS revealed the presence of multiple phenotypic biomarkers which distinguish Campylobacter fetus subsp. testudinum subsp. nov. from recognized subspecies of C. fetus.
Costly fertiliser holds back a green revolution in Africa
Giller, K.E. ; Gilbert, N. - \ 2014
The Guardian (2014).
Variation in dietary preferences, health, and performance in Holstein-Friesian Calves from 0 to 6 months of age provided free diet selection
Berends, H. ; Gerrits, W.J.J. ; Webb, L.E. ; Bokkers, E.A.M. ; Gilbert, M.S. ; Engel, B. ; Reenen, C.G. van - \ 2014
In: Proceedings of the 30th Biennial Conference of the Australian Society of Animal Production. - Australian Society of Animal Production - p. 231 - 231.
The effect of replacing lactose by glucose, fructose or glycerol in milk replacer on energy partitioning in Holstein-Friesian calves
Gilbert, M.S. ; Pantophlet, A.J. ; Borne, J.J.G.C. van den; Hendriks, W.H. ; Schols, H.A. ; Gerrits, W.J.J. - \ 2014
In: Proceedings of the 30th Biennial Conference of the Australian Society of Animal Production. - Australian Society of Animal Production - p. 113 - 113.
Small intestinal fermentation contributes substantially to starch disappearance in milk-fed calves
Gilbert, Myrthe - \ 2014
The effect of replacing lactose by glucose, fructose or glycerol on the energy partitioning of milk-fed calves
Gilbert, M.S. ; Pantophlet, A.J. ; Borne, J.J.G.C. van den; Hendriks, W.H. ; Schols, H.A. ; Gerrits, W.J.J. - \ 2014
In: Proceedings of the Wias Science Day 30 April 2014. - Wageningen : Wias Science Day - p. 22 - 22.
The effect of replacing lactose by glucose, fructose or glycerol on the energy partitioning of milk-fed calves
Gilbert, Myrthe - \ 2014
Estimation of milk leakage into the rumen of milk-fed calves through an indirect and repeatable method
Labussière, E. ; Berends, H. ; Gilbert, M.S. ; Borne, J.J.G.C. van den; Gerrits, W.J.J. - \ 2014
Animal 8 (2014)10. - ISSN 1751-7311 - p. 1643 - 1652.
acetaminophen absorption test - reticular groove reflex - veal calves - ruminal drinkers - performance - transit - growth
In milk-fed calves, quantification of the milk that enters the rumen (ruminal milk volume, RMV) because of malfunction of the esophageal groove reflex may explain part of the variability observed between animals in their growth performance. The RMV can directly be quantified by adding an indigestible marker to the diet and measuring its recovery in the rumen at slaughter, but this technique cannot be repeated in time in the same animal. The objective of the study was to evaluate three indirect methods for estimating RMV. The first method was based on the assumption that ruminal drinking delays and limits acetaminophen appearance in blood after ingestion of milk supplemented with acetaminophen. The second method was based on a negative linear relationship between RMV and urinary recovery of non-metabolizable monosaccharides (3-O-methylglucose, l-rhamnose and d-xylose) added to the milk, owing to rumen fermentation. In the third method, RMV was calculated as the difference between total milk intake and the increase in abomasal milk volume (AMV) at feeding, measured through ultrasonography shortly after feeding, or estimated from the mathematical extrapolation of AMV to feeding time, based on consecutive measurements. These methods were tested in three experiments where calves (n=22, 10 and 13) were bucket fed or partly tube fed (i.e. by inserting milk replacer into the rumen via a tube to mimic ruminal drinking). In addition, Co-EDTA and Cr-EDTA were used as an indigestible marker in one experiment to trace bucket-fed or tube-fed milk replacer, respectively, to measure RMV. The relationship between AMV measured by ultrasonography and AMV measured at slaughter improved when kinetics of AMV were extrapolated to the time of slaughter by mathematical modeling (error between predicted and measured AMV equaled 0.49 l). With this technique, RMV during feeding averaged 17% and 24% of intake in Experiments 2 and 3, respectively. Plasma acetaminophen kinetics and recovery of non-metabolizable monosaccharides in urine were partly associated with ruminal drinking, but these techniques are not considered quantitatively accurate without further information of rumen degradation and absorption. The recovery of indigestible marker measured at slaughter gave a quantitative estimate of RMV (2% in Experiment 3), but improper measurement of emptying rate of fluid from the rumen may lead to underestimation. In conclusion, measuring changes in AMV by ultrasonography, in response to milk feeding, was the most promising indirect method to quantify RMV in veal calves.
Small intestinal fermentation contributes substantially to starch disappearance in milk-fed calves
Gilbert, M.S. ; Pantophlet, A.J. ; Borne, J.J.G.C. van den; Schols, H.A. ; Gerrits, W.J.J. - \ 2014
Small intestinal fermentation contributes substantially to starch disappearance in milk-fed calves
Gilbert, M.S. ; Pantophlet, A.J. ; Borne, J.J.G.C. van den; Schols, H.A. ; Gerrits, W.J.J. - \ 2013
In: Proceedings of the 4th International Symposium on Energy and Protein Metabolism and Nutrition, 9-12 September 2013, Sacramento, California, USA. - Wageningen : Wageningen Academic Publishers - ISBN 9789086862276 - p. 59 - 60.
A titration approach to identify the capacity for starch digestion in milk-fed calves
Gilbert, M.S. ; Borne, J.J.G.C. van den; Pantophlet, A.J. ; Gerrits, W.J.J. - \ 2013
In: Proceedings of the 4th International Symposium on Energy and Protein Metabolism and Nutrition, 9-12 September 2013, Sacramento, California, USA. - Wageningen : Wageningen Academic Publishers - ISBN 9789086862276 - p. 233 - 234.
Calf milk replacers commonly contain 40-50% lactose. For economic reasons, starch is of interest as a lactose replacer. Compared with lactose, starch digestion is generally low in calves. Ileal disappearance of starch was only 60% in calves, whereas lactose disappeared for 97% (Coombe and Smith, 1974). This indicates that the activity of enzymes required for the hydrolysis of starch to glucose limits starch digestion in milk-fed calves. It is however unknown which enzyme system is limiting the rate of starch hydrolysis in the intestinal lumen of calves. In addition, a maximum may exist for the daily quantity of starch that can be hydrolyzed and absorbed. Potentially, enzyme systems may also adapt to the starch fed. Both may be subject to considerable inter-individual variation.
Testing methodologies for REDD+: Deforestation drivers, costs and reference levels
Angelsen, A. ; Ainembabazi, J.H. ; Bauch, S.C. ; Herold, M. ; Verchot, L. ; Hänsel, G. ; Schueler, V. ; Toop, G. ; Gilbert, A. ; Eisbrenner, K. - \ 2013
London, UK : Ecofys - 129 p.
Transcriptional dynamics of two seed compartments with opposing roles in Arabidopsis seed germination
Dekkers, S.J.W. ; Pearce, S. ; Bolderen-Veldkamp, R.P. ; Marshall, A. ; Widera, P. ; Gilbert, J. ; Drost, H.G. ; Bassel, G. ; Muller, K. ; King, J.R. ; Wood, A. ; Grosse, I. ; Bentsink, L. - \ 2013
Plant Physiology 163 (2013)1. - ISSN 0032-0889 - p. 205 - 215.
thaliana seeds - abscisic-acid - leaf senescence - gene activity - endosperm - reveals - dormancy - metabolism - embryo - touch
Seed germination is a critical stage in the plant life cycle and the first step toward successful plant establishment. Therefore, understanding germination is of important ecological and agronomical relevance. Previous research revealed that different seed compartments (testa, endosperm, and embryo) control germination, but little is known about the underlying spatial and temporal transcriptome changes that lead to seed germination. We analyzed genome-wide expression in germinating Arabidopsis (Arabidopsis thaliana) seeds with both temporal and spatial detail and provide Web-accessible visualizations of the data reported ( We show the potential of this high-resolution data set for the construction of meaningful coexpression networks, which provide insight into the genetic control of germination. The data set reveals two transcriptional phases during germination that are separated by testa rupture. The first phase is marked by large transcriptome changes as the seed switches from a dry, quiescent state to a hydrated and active state. At the end of this first transcriptional phase, the number of differentially expressed genes between consecutive time points drops. This increases again at testa rupture, the start of the second transcriptional phase. Transcriptome data indicate a role for mechano-induced signaling at this stage and subsequently highlight the fates of the endosperm and radicle: senescence and growth, respectively. Finally, using a phylotranscriptomic approach, we show that expression levels of evolutionarily young genes drop during the first transcriptional phase and increase during the second phase. Evolutionarily old genes show an opposite pattern, suggesting a more conserved transcriptome prior to the completion of germination.
Climate change and the spread of vector-borne diseases: using approximate Bayesian computation to compare invasion scenarios for the bluetongue virus vector Culicoides imicola in Italy
Mardulyn, P. ; Goffredo, M. ; Conte, A. ; Hendrickx, G. ; Meiswinkel, R. ; Balenghien, T. ; Sghaier, S. ; Lohr, Y. ; Gilbert, M. - \ 2013
Molecular Ecology 22 (2013)9. - ISSN 0962-1083 - p. 2456 - 2466.
multilocus genotype data - chain monte-carlo - population-structure - mediterranean basin - entomological surveillance - statistical evaluation - expanding populations - genetic diversity - range expansion - history
Bluetongue (BT) is a commonly cited example of a disease with a distribution believed to have recently expanded in response to global warming. The BT virus is transmitted to ruminants by biting midges of the genus Culicoides, and it has been hypothesized that the emergence of BT in Mediterranean Europe during the last two decades is a consequence of the recent colonization of the region by Culicoides imicola and linked to climate change. To better understand the mechanism responsible for the northward spread of BT, we tested the hypothesis of a recent colonization of Italy by C. imicola, by obtaining samples from more than 60 localities across Italy, Corsica, Southern France, and Northern Africa (the hypothesized source point for the recent invasion of C. imicola), and by genotyping them with 10 newly identified microsatellite loci. The patterns of genetic variation within and among the sampled populations were characterized and used in a rigorous approximate Bayesian computation framework to compare three competing historical hypotheses related to the arrival and establishment of C. imicola in Italy. The hypothesis of an ancient presence of the insect vector was strongly favoured by this analysis, with an associated P = 99%, suggesting that causes other than the northward range expansion of C. imicola may have supported the emergence of BT in southern Europe. Overall, this study illustrates the potential of molecular genetic markers for exploring the assumed link between climate change and the spread of diseases.
Sustainable Tourism
Fletcher, J.E. ; Amelung, B. - \ 2013
In: Tourism: Principles and Practice / Fletcher, J.E., Fyall, A., Gilbert, D.C., Wanhill, S.R.C., Harlow, UK : Pearson - ISBN 9780273758273 - p. 224 - 257.
Picomolar inhibition of cholera toxin by a pentavalent ganglioside GM1os-calix[5]arene
Garcia-Hartjes, J. ; Bernardi, S. ; Weijers, C.A.G.M. ; Wennekes, T. ; Gilbert, M. ; Sansone, F. ; Casnati, A. ; Zuilhof, H. - \ 2013
Organic & Biomolecular Chemistry 11 (2013). - ISSN 1477-0520 - p. 4340 - 4349.
heat-labile enterotoxin - gm1 mimics - binding - ligand - hexamethylenetetramine - oligosaccharide - recognition - affinity - crystal - design
Cholera toxin (CT), the causative agent of cholera, displays a pentavalent binding domain that targets the oligosaccharide of ganglioside GM1 (GM1os) on the periphery of human abdominal epithelial cells. Here, we report the first GM1os-based CT inhibitor that matches the valency of the CT binding domain (CTB). This pentavalent inhibitor contains five GM1os moieties linked to a calix[5]arene scaffold. When evaluated by an inhibition assay, it achieved a picomolar inhibition potency (IC50 = 450 pM) for CTB. This represents a significant multivalency effect, with a relative inhibitory potency of 100000 compared to a monovalent GM1os derivative, making GM1os-calix[5]arene one of the most potent known CTB inhibitors.
Data and models for exploring sustainability of human well-being in global environmental change
Deffuant, G. ; Alvarez, I. ; Barreteau, O. ; Vries, B. de; Edmonds, B. ; Gilbert, N. ; Gotts, N. ; Jabot, F. ; Janssen, S.J.C. ; Hilden, M. ; Kolditz, O. ; Murray-Rust, D. ; Rouge, C. ; Smits, P. - \ 2012
The European Physical Journal. Special Topics 214 (2012)1. - ISSN 1951-6355 - p. 519 - 545.
intermediate-complexity model - midlatitude atmospheric jet - extreme-value statistics - agent-based models - land-use - water management - decision-making - food systems - total-energy - simulation
This position paper proposes a vision for the research activity about sustainability in global environmental change (GEC) taking place in the FuturICT flagship project. This activity will be organised in an "Exploratory", gathering a core network of European scientists from ICT, social simulation, complex systems, economics, demographics, Earth system science. These research teams will collaborate in building a self-organising network of data sources and models about GEC and in using new facilities fostering stakeholder participation. We develop examples of concrete directions for this research: world wide virtual population with demographic and some economic descriptors, ecosystem services production and distribution, governance systems at various scales.
Small-angle neutron scattering study on self-assembled sitosterol-oryzanol tubules
Bot, A. ; Gilbert, E.P. ; Bouwman, W.G. ; Sawalha, H.I.M. ; Adel, R. den; Garamus, V.M. ; Venema, P. ; Linden, E. van der; Flöter, E. - \ 2012
The firmness of oil-continuous food products, such as margarine or butter, is based on a network of small crystallites of triglycerides. Few alternative routes to structure food grade oils are known that are not explained in essence by fatty acid crystallisation behaviour. One exception is the mixture of ¿-oryzanol with ß-sitosterol, which forms helical ribbons appearing as tubules through self-assembly. Small-angle neutron scattering was applied to organogels and emulsion gels based on these plant sterol systems, to investigate the structure of the sitosterol + oryzanol tubules in more detail. Special attention was given to contrast variation studies by using various solvents in which the sterol mixture had previously been shown to form tubules. The present study shows that the wall of the tubule can be considered to consist of two layers, of which the outer layer is composed of the ferulic acid moieties in the oryzanol. Further refinements in the tubule model are desirable to move the current semi-quantitative analysis to a quantitative one.
Livestock-associated MRSA ST398 carriage in pig slaughterhouse workers related to quantitative environmental exposure
Gilbert, M.J. ; Bos, M.E.H. ; Duim, B. ; Urlings, H.A.P. ; Heres, L. ; Wagenaar, J.A. ; Heederik, D.J.J. - \ 2012
Occupational and Environmental Medicine 69 (2012)7. - ISSN 1351-0711 - p. 472 - 478.
resistant staphylococcus-aureus - time pcr assay - methicillin-resistant - high prevalence - netherlands - endocarditis - infections - personnel - bacteria - contact
Objectives To assess livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) carriage among workers in pig slaughterhouses and assess associated risk factors, including occupational exposure to LA-MRSA. Methods A cross-sectional study in three Dutch pig slaughterhouses was undertaken. Nasal swabs of participants were taken. Nasal swabs and surface wipes, air and glove samples were screened for presence of methicillin-resistant Staphylococcus aureus (MRSA). MRSA was quantitatively determined on gloves and in air samples by culturing and real-time PCR. Results 11 of 341 (3.2%) participants were identified as nasal MRSA carriers. MRSA-positive workers were predominantly found at the start of the slaughter process. Major risk factors for carriage were working in the lairage and working in the scalding and dehairing area. Most nasal isolates (73%) belonged to the LA-MRSA clone ST398. MRSA ST398-positive environmental samples were found throughout the slaughter process. A clear decrease was seen along the slaughterline in the number of MRSA-positive samples and in the MRSA amount per sample. Conclusions This study showed that working in the lairage area or scalding and dehairing area were the major risk factors for MRSA carriage in pig slaughterhouse workers, while the overall prevalence of MRSA carriage is low. Occupational exposure to MRSA decreased along the slaughterline, and the risk of carriage showed a parallel decrease.
Elucidation of density profile of self-assembled sitosterol + oryzanol tubules with small-angle neutron scattering
Bot, A. ; Gilbert, E.P. ; Bouwman, W.G. ; Sawalha, H.I.M. ; Adel, R. den; Garamus, V.M. ; Venema, P. ; Linden, E. van der; Flöter, E. - \ 2012
Faraday Discussions 158 (2012). - ISSN 1359-6640 - p. 223 - 238.
gamma-oryzanol - beta-sitosterol - edible oils - fatty alcohols - mixtures - organogels - emulsions - wax - fa
Small-angle neutron scattering (SANS) experiments have been performed on self-assembled tubules of sitosterol and oryzanol in triglyceride oils to investigate details of their structure. Alternative organic phases (deuterated and non-deuterated decane, limonene, castor oil and eugenol) were used to both vary the contrast with respect to the tubules and investigate the influence of solvent chemistry. The tubules were found to be composed of an inner and an outer shell containing the androsterol group of sitosterol or oryzanol and the ferulic acid moieties in the oryzanol molecule, respectively. While the inner shell has previously been detected in SAXS experiments, the outer shell was not discernible due to similar scattering length density with respect to the surrounding solvent for X-rays. By performing contrast variation SANS experiments, both for the solvent and structurant, a far more detailed description of the self-assembled system is obtainable. A model is introduced to fit the SANS data; we find that the dimensions of the inner shell agree quantitatively with the analysis performed in earlier SAXS data (radius of 39.4 +/- 5.6 A for core and inner shell together, wall thickness of 15.1 +/- 5.5 A). However, the newly revealed outer shell was found to be thinner than the inner shell (wall thickness 8.0 +/- 6.5 A). The changes in the scattering patterns may be explained in terms of the contrast between the structurant and the organic phase and does not require any subtle indirect effects caused by the presence of water, other than water promoting the formation of sitosterol monohydrate in emulsions with aqueous phases with high water activity
Self-conscious emotions and social functioning
Hooge, I.E. de; Zeelenberg, M. ; Breugelmans, S.M. - \ 2011
In: Emotion Regulation and Well-Being / Nyklicek, I., Vingerhoets, A. J. J. M., Zeelenberg, M., New York : Springer Publishers - ISBN 9781441969521 - p. 197 - 210.
Introduction Have you ever felt guilty about hurting a loved one, or been proud after achieving something that you always dreamed of? These emotions, but also embarrassment, shame, and hubris, are called self-conscious emotions. They are a special kind of emotions that cannot be described solely by examining facial movements (Darwin, 1872/1965) and that do not have clear, distinct elicitors (Lewis, 2000). Selfconscious emotions are cognitively complex and play a central role in the motivation and regulation of thoughts, feelings, and behaviors (Baumeister, Stillwell, & Heatherton, 1994; Leith & Baumeister, 1998; Tangney & Fischer, 1995). Until now, most research concerning the relationship between self-conscious emotions and social behavior has focused on their anticipation affects of what people do (e.g., Gruenewald, Dickerson, & Kemeny, 2007; Keltner & Buswell, 1997; Tracy & Robins, 2004). The anticipation of negative self-conscious emotions such as shame or guilt can motivate avoidance of immoral or asocial behavior (I will not do that, otherwise I will feel ashamed), and the anticipation of positive self-conscious emotions such as pride can stimulate compliance with social and moral norms (If I do that, I will be proud of myself). Also, actual experiences of self-conscious emotions may exert an influence. For example, when people feel ashamed, they do certain things because of that (e.g., hide or try to appease). The aim of the present chapter is to shed some light on how experiences of self-conscious emotions are regulated and as such influence social behavior. We will start with a discussion concerning the definition of self-conscious emotions and how they differ from so-called basic emotions. Then the focus shifts to existing research concerning the influences of self-conscious emotions on moral and social behavior. We will discuss how these often-contrasting findings can be interpreted using an emotion-specific approach. Finally, two self-conscious emotions, namely shame and guilt will be highlighted. We will explain how our approach can clarify the contrasting, empirical findings concerning the influences of shame and guilt on behavior (e.g., Gilbert & Andrews, 1998; Lewis, 1971, 1992; Tangney & Dearing, 2002; Tangney & Fischer, 1995).
Climate related shifts in the NCP ecosystem, and consequences for future spatial planning
Meer, J. van der; Lindeboom, H.J. ; Woerd, H.J. van der; Eleveld, M.A. ; Gilbert, A.J. ; Peters, S.W.M. ; Peperzak, L. ; Duineveld, G.C.A. ; Bergman, M.J.N. ; Lavaleye, M.S.S. ; Daan, R. ; Saraiva, A.S. ; Hal, R. van; Tulp, I. ; Craeymeersch, J.A.M. ; Daan, N. ; Labberton, R. ; Stuke, F. ; Teal, L.R. ; Rijnsdorp, A.D. ; Witbaard, R. ; Ruardij, P. ; Meesters, H.W.G. ; Baar, H.J.W. ; Meijer, H.A.J. ; Thomas, H. ; Johannesen, T. ; Zemmelink, H.J. ; Omari, A. ; Straten, H.J. ; Klunder, M. ; Salt, L. ; Laan-Luijkx, I.T. van der - \ 2011
Amsterdam : Programme Office Climate changes Spatial Planning - ISBN 9789088150180 - 36
klimaatverandering - mariene gebieden - landgebruiksplanning - aquatische ecosystemen - broeikasgassen - noordzee - climatic change - marine areas - land use planning - aquatic ecosystems - greenhouse gases - north sea
Een uitgebreide meetinspanning op de Noordzee, in combinatie met wiskundige en statistische modellering, laat zien dat de klimaatveranderingen in de vorm van een verandering in de overheersende windrichting, een toename van de windsnelheid, een toename van de zeewatertemperatuur, als wel als een toenemende CO2 concentratie van de atmosfeer, niet alleen leidt tot een verandering van de samenstelling van het zeewater in de vorm van bijvoorbeeld opgelost anorganisch koolstof en zuurgraad, maar ook tot een, zei het beperkte, verlaging van de productiviteit van op en in de zeebodem levende filterende organismen, die op hun beurt het voedsel zijn van bodembewonende vissen.
Progeny-testing of full-sibs IBD in a SSC2 QTL region highlights epistatic interactions for fatness traits in pigs
Tortereau, F.J.D. ; Sanchez, M.P. ; Feve, K. ; Gilbert, H. ; Iannuccelli, N. ; Billon, Y. ; Milan, D. ; Bidanel, J.P. ; Riquet, J. - \ 2011
BMC Genetics 12 (2011). - ISSN 1471-2156
large white-pigs - backfat thickness - alternative models - imprinted qtl - genome scan - muscle mass - sus-scrofa - igf2 locus - growth - carcass
Background: Many QTL have been detected in pigs, but very few of them have been fine-mapped up to the causal mutation. On SSC2, the IGF2-intron3-G3072A mutation has been described as the causative polymorphism for a QTL underlying muscle mass and backfat deposition, but further studies have demonstrated that at least one additional QTL should segregate downstream of this mutation. A marker-assisted backcrossing design was set up in order to confirm the segregation of this second locus, reduce its confidence interval and better understand its mode of segregation. Results: Five recombinant full-sibs, with genotype G/G at the IGF2 mutation, were progeny-tested. Only two of them displayed significant QTL for fatness traits although four inherited the same paternal and maternal chromosomes, thus exhibiting the same haplotypic contrast in the QTL region. The hypothesis of an interaction with another region in the genome was proposed to explain these discrepancies and after a genome scan, four different regions were retained as potential interacting regions with the SSC2 QTL. A candidate interacting region on SSC13 was confirmed by the analysis of an F2 pedigree, and in the backcross pedigree one haplotype in this region was found to mask the SSC2 QTL effect. Conclusions: Assuming the hypothesis of interactions with other chromosomal regions, the QTL could be unambiguously mapped to a 30 cM region delimited by recombination points. The marker-assisted backcrossing design was successfully used to confirm the segregation of a QTL on SSC2 and, because full-sibs that inherited the same alleles from their two parents were analysed, the detection of epistatic interactions could be performed between alleles and not between breeds as usually done with the traditional Line-Cross model. Additional analyses of other recombinant sires should provide more information to further improve the fine-mapping of this locus, and confirm or deny the interaction identified between chromosomes 2 and 13.
Detection of antibodies in neuropathy patients by synthetic GM1 mimics
Pukin, A. ; Jacobs, B.C. ; Tio-Gillen, A.P. ; Gilbert, M. ; Endtz, H.P. ; Belkum, A. van; Visser, G.M. ; Zuilhof, H. - \ 2011
Glycobiology 21 (2011)12. - ISSN 0959-6658 - p. 1642 - 1650.
guillain-barre-syndrome - antiganglioside complex antibodies - miller-fisher-syndrome - multifocal motor neuropathy - ganglioside complexes - anti-gm1 antibodies - severe disability - diagnostic-value - target antigens - ophthalmoplegia
Antibodies to the ganglioside GM1 are associated with various forms of acute and chronic immune-mediated neuropathy, including Guillain–Barré syndrome (GBS) and multifocal motor neuropathy. In diagnostics and research, these antibodies are usually detected by GM1 preparations derived from bovine brain tissue, which are non-covalently attached to solid carriers such as enzyme-linked immunosorbent assay (ELISA) plates. Such brain-derived GM1 preparations are potentially contaminated with other glycolipids. In the current study, uncontaminated mono- and divalent synthetic analogs of the ganglioside GM1 were successfully attached via covalent bonds onto the surface of ELISA plates. The resulting modified diagnostic tool showed strong affinities and good specificities for binding of monoclonal mouse and human anti-GM1 antibodies and cholera toxin, as well as for the anti-GM1 antibodies in serum samples from neuropathy patients. While these proof-of-principle experiments reveal the potential of synthetic ganglioside mimics in diagnostics, they show the necessity of further studies to overcome certain limitations, specifically the non-specific interactions in the negative control assays with synthetic GM1.
Chemoenzymatic synthesis of biotin-appended analogues of gangliosides GM2, GM1, GD1 and GalNAc-GD1a for solid-phase applications and improved ELISA tests
Pukin, A. ; Florack, D.E.A. ; Brochu, D. ; Lagen, B. van; Visser, G.M. ; Wennekes, T. ; Gilbert, M. ; Zuilhof, H. - \ 2011
Organic & Biomolecular Chemistry 9 (2011)16. - ISSN 1477-0520 - p. 5809 - 5815.
surface-plasmon resonance - carbohydrate microarrays - campylobacter-jejuni - cholera-toxin - oligosaccharide microarrays - biological-systems - guillain-barre - nmr analysis - binding - sugar
Biotinylated analogues of gangliosides GM2, GM1, GD1a and GalNAc-GD1a were synthesized in high yields using glycosyltransferases from Campylobacter jejuni. The presence of a biotin moiety in the aglycone part of these mimics allows for attachment of these materials onto various streptavidin-coated surfaces. Analysis of the interaction of biotin-appended GM1 with the B subunit of Escherichia coli heat-labile enterotoxin performed in a modified ELISA procedure shows the potential of this compound to replace the natural GM1 in toxin detection.
Number and mode of inheritance of QTL influencing backfat thickness on SSC2p in Sino-European pig pedigrees
Tortereau, F.J.D. ; Gilbert, H.J. ; Heuven, H.C.M. ; Bidanel, J.P. ; Groenen, M.A.M. ; Riquet, J. - \ 2011
Genetics, Selection, Evolution 43 (2011). - ISSN 0999-193X - 9 p.
quantitative trait loci - igf2-intron3-g3072a substitution - carcass composition - alternative models - colorectal-cancer - affecting growth - imprinted qtl - meat quality - muscle mass - sus-scrofa
Background In the pig, multiple QTL associated with growth and fatness traits have been mapped to chromosome 2 (SSC2) and among these, at least one shows paternal expression due to the IGF2-intron3-G3072A substitution. Previously published results on the position and imprinting status of this QTL disagree between analyses from French and Dutch F2 crossbred pig populations obtained with the same breeds (Meishan crossed with Large White or Landrace). MethodsTo study the role of paternal and maternal alleles at the IGF2 locus and to test the hypothesis of a second QTL affecting backfat thickness on the short arm of SSC2 (SSC2p), a QTL mapping analysis was carried out on a combined pedigree including both the French and Dutch F2 populations, on the progeny of F1 males that were heterozygous (A/G) and homozygous (G/G) at the IGF2 locus. Simulations were performed to clarify the relations between the two QTL and to understand to what extent they can explain the discrepancies previously reported. Results The QTL analyses showed the segregation of at least two QTL on chromosome 2 in both pedigrees, i.e. the IGF2 locus and a second QTL segregating at least in the G/G F1 males and located between positions 30 and 51 cM. Statistical analyses highlighted that the maternally inherited allele at the IGF2 locus had a significant effect but simulation studies showed that this is probably a spurious effect due to the segregation of the second QTL. Conclusions Our results show that two QTL on SSC2p affect backfat thickness. Differences in the pedigree structures and in the number of heterozygous females at the IGF2 locus result in different imprinting statuses in the two pedigrees studied. The spurious effect observed when a maternally allele is present at the IGF2 locus, is in fact due to the presence of a second closely located QTL. This work confirms that pig chromosome 2 is a major region associated with fattening traits.
Selective Depletion of Neuropathy-Related Antibodies from Human Serum by Monolithic Affinity Columns Containing Ganglioside Mimics
Tetala, K.K.R. ; Heikema, A.P. ; Pukin, A. ; Weijers, C.A.G.M. ; Tio-Gillen, A.P. ; Gilbert, M. ; Endtz, H.P. ; Belkum, A. van; Zuilhof, H. ; Visser, G.M. ; Jacobs, B.C. ; Beek, T.A. van - \ 2011
Journal of Medical Chemistry 54 (2011)10. - ISSN 0022-2623 - p. 3500 - 3505.
guillain-barre-syndrome - carbohydrate microarrays - capillary columns - silicon surfaces - binding proteins - chromatography - gm2 - monolayers - mannose - lectins
Monolithic columns containing ganglioside GM2 and GM3 mimics were prepared for selective removal of serum anti-ganglioside antibodies from patients with acute and chronic immune-mediated neuropathies. ELISA results demonstrated that anti-GM2 IgM antibodies in human sera and a mouse monoclonal anti-GM2 antibody were specifically and selectively adsorbed by monolithic GM2 mimic columns and not by blank monolithic columns or monolithic GM3 mimic columns. In control studies, serum antibodies against the ganglioside GQ1b from another neuropathy patient were not depleted by monolithic GM2 mimic columns. Fluorescence microscopy with FITC-conjugated anti-human immunoglobulin antibodies showed that the immobilized ganglioside mimics were evenly distributed along the column. The columns were able to capture 95% of the anti-GM2 antibodies of patients after only 2 min of incubation. A monolithic column of 4.4 µL can deplete 28.2 µL of undiluted serum. These columns are potential diagnostic and therapeutic tools for neuropathies related to anti-ganglioside antibodies.
Wat leren ze daar nu nog op school? (interview met Derk Jan Stobbelaar en Gilbert Leistra
Stobbelaar, D.J. ; Leistra, G.R. ; Duinhoven, G. van - \ 2010
Vakblad Natuur Bos Landschap (2010)juni. - ISSN 1572-7610 - p. 24 - 25.
natuurbescherming - hoger onderwijs - natuurbeheer - kennismanagement - nature conservation - higher education - nature management - knowledge management
Het zijn de bekende verhalen van werkgevers: “Ik heb een afgestudeerde aangenomen van een hbo-opleiding, maar hij kan nog niet eens blessen. Wat leren ze daar nu nog op school?” Misschien een beetje karikaturaal maar de aansluiting tussen onderwijs en werkveld is niet altijd voor iedereen vanzelfsprekend. Daarom een gesprek met: Jesse de Muijnk (Helicon Opleidingen MBO Velp), Gilbert Leistra en Derk Jan Stobbelaar (Van Hall Larenstein) en coördinatoren van het programma Natuur & Landschap van de Groene Kennis Coöperatie. Welke kennis mag je verwachten van een afgestudeerde en wat kan zo iemand?
Comparison of two pig pedigrees regarding the effect of the IGF2 mutation on backfat.
Tortereau, F.J.D. ; Gilbert, H.J. ; Heuven, H.C.M. ; Bidanel, J.P. ; Groenen, M.A.M. ; Riquet, J. - \ 2010
In: Proceedings of the 9th World Congress on Genetic Applied to Livestock Production (WCGALP), Leipzig, Germany, 1-6 August 2010. - - p. 1 - 4.
Combining two Meishan F2 crosses improves the detection of QTL on pig chromosomes 2. 4 and 6
Tortereau, F.J.D. ; Gilbert, H.J. ; Heuven, H.C.M. ; Bidanel, J.P. ; Groenen, M.A.M. ; Riquet, J. - \ 2010
Genetics, Selection, Evolution 42 (2010). - ISSN 0999-193X
quantitative trait loci - meat quality traits - sus-scrofa - confidence-intervals - alternative models - teat number - linkage - growth - populations - carcass
Background - In pig, a number of experiments have been set up to identify QTL and a multitude of chromosomal regions harbouring genes influencing traits of interest have been identified. However, the mapping resolution remains limited in most cases and the detected QTL are rather inaccurately located. Mapping accuracy can be improved by increasing the number of phenotyped and genotyped individuals and/or the number of informative markers. An alternative approach to overcome the limited power of individual studies is to combine data from two or more independent designs. Methods - In the present study we report a combined analysis of two independent design (a French and a Dutch F2 experimental designs), with 2000 F2 individuals. The purpose was to further map QTL for growth and fatness on pig chromosomes 2, 4 and 6. Using QTL-map software, uni- and multiple-QTL detection analyses were applied separately on the two pedigrees and then on the combination of the two pedigrees. Results - Joint analyses of the combined pedigree provided (1) greater significance of shared QTL, (2) exclusion of false suggestive QTL and (3) greater mapping precision for shared QTL. Conclusions - Combining two Meishan x European breeds F2 pedigrees improved the mapping of QTL compared to analysing pedigrees separately. Our work was facilitated by the access to raw phenotypic data and DNA of animals from both pedigrees and the combination of the two designs with the addition of new markers allowed us to fine map QTL without phenotyping additional animals.
A-programma zet stap B : natuur en landschap gaat om de 'wensen van mensen' (interview met Derk Jan Stobbelaar en Gilbert Leistra)
Stobbelaar, Derk Jan ; Leistra, G.R. - \ 2009
Vakblad Groen Onderwijs 51 (2009)9. - ISSN 1568-8704 - p. 24 - 26.
agrarisch onderwijs - landschap - onderwijsinstellingen - onderwijsprogramma's - natuurbeheer - natuur - natuurlandschap - agricultural education - landscape - educational institutions - education programmes - nature management - nature - natural landscape
Het A-programma Natuur en landschap draait nu anderhalf jaar. Programmaleider Derk Jan Stobbelaar en secretaris Gilbert Leistra vertellen, aan de hand van het uitvoeringsplan, over de stand van zaken en hun visie. En nodigen uit mee te denken
Chaos revisited: nomenclature and typification of the Malagasy endemic Euphorbia subgenus Lacanthis (Raf.) M.G. Gilbert.
Haevermans, Th. ; Rouhan, G. ; Hetterscheid, W.L.A. ; Teissier, M. ; Belarbi, K. ; Aubriot, X. ; Labat, J.N. - \ 2009
Adansonia 31 (2009)2. - ISSN 1280-8571 - p. 279 - 299.
Malagasy relatives of the Crown-of-Th orns (Euphorbia milii Des Moul.) are well known worldwide for their ornamental value. Malagasy taxa account for almost 10% of the genus Euphorbia L., with 110 accepted names constituting subgenus Lacanthis (Raf.) M.G.Gilbert. Th e chaotic taxonomy combined with the poor state of preservation of most herbarium specimens makes the systematic study of this huge genus a quite diffi cult task. Th is paper off ers a nomenclatural account of all the published names with a recapitulatory list citing all the accepted names in subgenus Lacanthis as a fi rst step towards the revision of the group.
Developmental complexity of arabinan polysaccharides and their processing in plant cell walls
Verhertbruggen, Y. ; Marcus, S.E. ; Haeger, A. ; Verhoef, R.P. ; Schols, H.A. ; McCleary, B.V. ; McKee, L. ; Gilbert, H.J. ; Knox, J.P. - \ 2009
The Plant Journal 59 (2009). - ISSN 0960-7412 - p. 413 - 425.
galactan side-chains - rhamnogalacturonan-i - arabinogalactan proteins - pectic polysaccharides - monoclonal-antibodies - diferulic bridges - arabidopsis - homogalacturonan - biosynthesis - degradation
Plant cell walls are constructed from a diversity of polysaccharide components. Molecular probes directed to structural elements of these polymers are required to assay polysaccharide structures in situ, and to determine polymer roles in the context of cell wall biology. Here, we report on the isolation and the characterization of three rat monoclonal antibodies that are directed to 1,5-linked arabinans and related polymers. LM13, LM16 and LM17, together with LM6, constitute a set of antibodies that can detect differing aspects of arabinan structures within cell walls. Each of these antibodies binds strongly to isolated sugar beet arabinan samples in ELISAs. Competitive-inhibition ELISAs indicate the antibodies bind differentially to arabinans with the binding of LM6 and LM17 being effectively inhibited by short oligoarabinosides. LM13 binds preferentially to longer oligoarabinosides, and its binding is highly sensitive to arabinanase action, indicating the recognition of a longer linearized arabinan epitope. In contrast, the binding of LM16 to branched arabinan and to cell walls is increased by arabinofuranosidase action. The presence of all epitopes can be differentially modulated in vitro using glycoside hydrolase family 43 and family 51 arabinofuranosidases. In addition, the LM16 epitope is sensitive to the action of ß-galactosidase. Immunofluorescence microscopy indicates that the antibodies can be used to detect epitopes in cell walls, and that the four antibodies reveal complex patterns of epitope occurrence that vary between organs and species, and relate both to the probable processing of arabinan structural elements and the differing mechanical properties of cell walls.
Are changes in the composition of the Fusarium Head Blight complex caused by climate change?
Waalwijk, C. ; Lee, T.A.J. van der; Yang, L. ; Vries, P.M. de; Kema, G.H.J. - \ 2009
Fusarium Head Blight (FHB) of wheat and barley is caused by a complex of species. Apart from yield losses, this disease has attracted much attention due to the capacity of many of the species in the complex to produce mycotoxins that are detrimental to humans and animals. In The Netherlands, until the late 1980s / early 1990s, Fusarium culmorum was the predominant species on wheat, but since then F. graminearum became the most important pathogen. This trend was first detected in 2000 and 2001 (Waalwijk et al., 2003) and was confirmed in other countries in Western Europe. This finding can be explained in several ways, including the expansion of the acreage of maize, which is a good host of F. graminearum, but less for F. culmorum. Secondly, F. graminearum has the capacity to go through sexual development, resulting in airborne ascospores that can travel several hundreds of kilometers; a clear advantage in colonization of crops in virgin soils. Lastly, F. graminearum favors higher temperatures than F. culmorum and the observed shift might be an indication of changes in climate. In China, the population structure of FHB pathogens occurring on barley was investigated by sampling at 23 counties along the Yangtze River. In contrast to the situation in Europe or North America, the vast majority of isolates belong to F. asiaticum. Analyses of the structure of this population showed a dramatic gradient in the trichothecene mycotoxins produced (Yang et al., 2008). While the production of nivalenol (NIV) was primarily found among isolates collected in the western part of the country, deoxynivalenol (DON) producers were mainly from the eastern provinces. As NIV producers have been reported in Asia in the past, we hypothesized that NIV producers represent the ancient population that is being replaced in the lowlands in the east. The populations in the western parts of China are not (yet) replaced as these counties reside in mountainous areas which are more difficult to become colonized by the DON producers. A similar gradient was observed in Canada, where populations from the FHB complex in the East appear to overtake the place of those in the West. Phenotypic analyses showed that the `invading¿ population consisted of strains that produced more mycotoxin and were more vigorous (Ward et al., 2008). To verify whether a similar situation is currently taking place in China, we analyzed the diversity within and between populations using neutral VNTR markers. Some alleles were observed exclusively in upper valleys of the Yangtze River (Zhang et al.) which is in agreement with the occurrence of genetic differentiation along environmental gradients. These results will be discussed together with data from a novel survey performed in the Netherlands in 2008, to underline the previously observed temporal shifts in the composition of the FHB complex. To put this in a broader perspective, this will be compared with results from surveys in France and Germany, where similar analyses were also performed on maize (Görtz et al.) References Görtz, A., Zuehlke, S., Steiner, U., Dehne, H.W., Waalwijk, C., de Vries, I. & Oerke, E.C. (in preparation). Maize ear rot caused by Fusarium spp. in Germany: year-to-year variability in mycotoxin contamination and species profile. Waalwijk, C., Kastelein, P., Vries, P.M. de, Kerenyi, Z., Lee, T. van der, Hesselink, T., Kohl, J. & Kema, G.H.J., 2003. Major changes in Fusarium spp. in wheat in the Netherlands. European Journal of Plant Pathology 109: 743-754. Ward, T.D., Clear, R.M., Rooney, A.P., O¿Donnell, K., Gaba, D., Patrick, S., Starkey, D.E., Gilbert, J., Geiser, D.M. & Nowicki, T.W., 2008. An adaptive evolutionary shift in Fusarium head blight pathogen populations is driving the rapid spread of more toxigenic Fusarium graminearum in North America. Fungal Genetics & Biology 45: 473-484. Yang, L.J., Lee, T.A.J. van der, Yang, X.J., Yu, D.Z. & Waalwijk, C., 2008. Fusarium populations on Chinese barley show a dramatic gradient in mycotoxin profiles. Phytopathology 98: 719-727. Zhang, Z., Zhang, H., Lee, T.A.J. van der, Li, C., Arens, P., Xu, J., Xu, J.S., Yang, L.J., Yu, D.Z., Waalwijk, C. & Feng, J. (submitted) Genetic diversity studies of Fusarium species on barley in China show a clear substructure associated with their geographic origin.
The Influence of Ligand Valency on Aggregation Mechanisms for Inhibiting Bacterial Toxins
Sisu, C. ; Baron, A.J. ; Branderhorst, H.M. ; Connell, S.D. ; Weijers, C.A.G.M. ; Vries, R. de; Hayes, E.D. ; Pukin, A.V. ; Gilbert, M. ; Pieters, R.J. ; Zuilhof, H. ; Visser, G.M. ; Turnbull, W.B. - \ 2009
ChemBioChem 10 (2009)2. - ISSN 1439-4227 - p. 329 - 337.
heat-labile enterotoxin - isothermal titration calorimetry - size-distribution analysis - cholera-toxin - escherichia-coli - receptor-binding - analytical ultracentrifugation - carbohydrate interactions - vibrio-cholerae - gm1 mimics
Divalent and tetravalent analogues of ganglioside GM1 are potent inhibitors of cholera toxin and Escherichia coli heat-labile toxin. However, they show little increase in inherent affinity when compared to the corresponding monovalent carbohydrate ligand. Analytical ultracentrifugation and dynamic light scattering have been used to demonstrate that the multivalent inhibitors induce protein aggregation and the formation of space-filling networks. This aggregation process appears to arise when using ligands that do not match the valency of the protein receptor. While it is generally accepted that multivalency is an effective strategy for increasing the activity of inhibitors, here we show that the valency of the inhibitor also has a dramatic effect on the kinetics of aggregation and the stability of intermediate protein complexes. Structural studies employing atomic force microscopy have revealed that a divalent inhibitor induces head-to-head dimerization of the protein toxin en route to higher aggregates
Verkerk, R. ; Dekker, M. - \ 2008
In: Bioactive Compounds in Foods / Gilbert, J., Senyuva, H.Z., Blackwell Publishing - ISBN 9781405158756 - p. 31 - 51.
A wind density model to quantify the airborne spread of culicoides species
Hendrickx, G. ; Gilbert, M. ; Staubach, C. ; Elbers, A.R.W. ; Mintiens, K. ; Gerbier, G. ; Ducheyne, E. - \ 2008
Preventive Veterinary Medicine 87 (2008)1-2. - ISSN 0167-5877 - p. 162 - 181.
possible windborne spread - mouth-disease virus - united-kingdom - air streams - vectors - ceratopogonidae - identification - diptera - surveillance - serotype-2
Increased transport and trade as well as climate shifts play an important role in the introduction, establishment and spread of new pathogens. Arguably, the introduction of bluetongue virus (BTV) serotype 8 in Benelux, Germany and France in 2006 is such an example. After its establishment in receptive local vector and host populations the continued spread of such a disease in a suitable environment will mainly depend on movement of infected vectors and animals. In this paper we explore how wind models can contribute to explain the spread of BTV in a temperate eco-climatic setting. Based on previous work in Greece and Bulgaria filtered wind density maps were computed using data from the European Centre for Medium-Range Weather Forecasts (ECMWF). Six hourly forward wind trajectories were computed at pressure levels of 850 hPa for each infected farm as from the recorded onset of symptoms. The trajectories were filtered to remove wind events that do not contribute to possible spread of the vector. The suitable wind events were rastered and aggregated on a weekly basis to obtain weekly wind density maps. Next to this, cumulated wind density maps were also calculated to assess the overall impact of wind dispersal of vectors. A strong positive correlation was established between wind density data and the horizontal asymmetrical spread pattern of the 2006 BTV8 epidemic. It was shown that short (31 km) distance spread had a different impact on disease spread. Computed wind densities were linked to the medium/long-distance spread whilst short range spread was mainly driven by active Culicoides flight. Whilst previous work in the Mediterranean basin showed that wind driven spread of Culicoides over sea occurred over distances of up to 700 km, this phenomenon was not observed over land. Long-distance spread over land followed a hopping pattern, i.e. with intermediary stops and establishment of local virus circulation clusters at distances of 35¿85 km. Despite suitable wind densities, no long range spread was recorded over distances of 300¿400 km. Factors preventing spread Eastwards to the UK and Northwards to Denmark during the 2006 epidemic are discussed. Towards the east both elevation and terrain roughness, causing air turbulences and drop down of Culicoides, were major factors restricting spread. It is concluded that the proposed approach opens new avenues for understanding the spread of vector-borne viruses in Europe. Future developments should take into consideration both physical and biological factors affecting spread.
GM3, GM2 and GM1 mimics designed for biosensing: chemoenzymatic synthesis, target affinities and 900 MHz NMR analysis
Pukin, A.V. ; Weijers, C.A.G.M. ; Lagen, B. van; Wechselberger, R. ; Sun, B. ; Gilbert, M. ; Karwaski, M.F. ; Florack, D.E.A. ; Jacobs, B.C. ; Tio-Gillen, A.P. ; Belkum, A. van; Endtz, H.P. ; Visser, G.M. ; Zuilhof, H. - \ 2008
Carbohydrate Research : an international journal 343 (2008)4. - ISSN 0008-6215 - p. 636 - 650.
covalently attached monolayers - crystalline silicon surfaces - nuclear-magnetic-resonance - extremely mild attachment - heat-labile enterotoxin - one-pot synthesis - campylobacter-jejuni - cholera-toxin - solid-phase - guillain-barre
Undec-10-enyl, undec-10-ynyl and 11-azidoundecyl glycoside analogues corresponding to the oligosaccharides of human gangliosides GM3, GM2 and GM1 were synthesized in high yields using glycosyltransferases from Campylobacter jejuni. Due to poor water solubility of the substrates, the reactions were carried out in methanol¿water media, which for the first time were shown to be compatible with the C. jejuni ¿-(2¿3)-sialyltransferase (CST-06) and ß-(1¿4)-N-acetylgalactosaminyltransferase (CJL-30). Bioequivalence of our synthetic analogues and natural gangliosides was examined by binding to Vibrio cholerae toxin and to the B subunit of Escherichia coli heat-labile enterotoxin. This bioequivalence was confirmed by binding mouse and human monoclonal antibodies to GM1 and acute phase sera containing IgM and IgG antibodies to GM1 from patients with the immune-mediated polyneuropathy Guillain¿Barré syndrome. The synthesized compounds were analyzed by 1D and 2D 900 MHz NMR spectroscopy. TOCSY and DQF-COSY experiments in combination with 13C¿1H correlation measurements (HSQC, HMBC) were carried out for primary structural characterization, and a complete assignment of all 1H and 13C chemical shifts is presented.
Strong Inhibition of Cholera Toxin by Multivalent GM1 Derivatives
Pukin, A.V. ; Branderhorst, H.M. ; Sisu, C. ; Weijers, C.A.G.M. ; Gilbert, M. ; Liskamp, R.M.J. ; Visser, G.M. ; Zuilhof, H. ; Pieters, R.J. - \ 2007
ChemBioChem 8 (2007)13. - ISSN 1439-4227 - p. 1500 - 1503.
heat-labile enterotoxin - crystalline silicon surfaces - linked organic monolayers - escherichia-coli - carbohydrate ligands - solid-phase - b-subunit - binding - oligosaccharide - dendrimers
(Chemical Equation Presented) Sticky fingers. The optimal ligand for the cholera toxin (CT), GM1-oligosaccharide (GM1os), was linked to dendritic structures that contained long spacer arms by using highly efficient "click" chemistry coupling. In the inhibition studies very large multivalency effects were observed; the best structure was an unprecedented 380 000-fold more potent ligand for the toxin than a monovalent GM1os derivative
Promiscuous, non-catalytic, tandem carbohydrate-binding modules modulate the cell-wall structure and development of transgenic tobacco (Nicotiana tabacum) plants
Olawole, O. ; Jacobsen, E. ; Timmers, J.F.P. ; Gilbert, H.J. ; Blake, W. ; Knox, J.P. ; Visser, R.G.F. ; Vincken, J.P. - \ 2007
Journal of Plant Research 120 (2007)5. - ISSN 0918-9440 - p. 605 - 617.
arabidopsis-thaliana - bacterial cellulose - gene-expression - growth - xyloglucan - polysaccharides - protein - endo-1,4-beta-glucanase - recognition - elongation
We have compared heterologous expression of two types of carbohydrate binding module (CBM) in tobacco cell walls. These are the promiscuous CBM29 modules (a tandem CBM29-1-2 and its single derivative CBM29-2), derived from a non-catalytic protein1, NCP1, of the Piromyces equi cellulase/hemicellulase complex, and the less promiscuous tandem CBM2b-1-2 from the Cellulomonas fimi xylanase 11A. CBM-labelling studies revealed that CBM29-1-2 binds indiscriminately to every tissue of the wild-type tobacco stem whereas binding of CBM2b-1-2 was restricted to vascular tissue. The promiscuous CBM29-1-2 had much more pronounced effects on transgenic tobacco plants than the less promiscuous CBM2b-1-2. Reduced stem elongation and prolonged juvenility, resulting in delayed flower development, were observed in transformants expressing CBM29-1-2 whereas such growth phenotypes were not observed for CBM2b-1-2 plants. Histological examination and electron microscopy revealed layers of collapsed cortical cells in the stems of CBM29-1-2 plants whereas cellular deformation in the stem cortical cells of CBM2b-1-2 transformants was less severe. Altered cell expansion was also observed in most parts of the CBM29-1-2 stem whereas for the CBM2b-1-2 stem this was observed in the xylem cells only. The cellulose content of the transgenic plants was not altered. These results support the hypothesis that CBMs can modify cell wall structure leading to modulation of wall loosening and plant growth.
A phytosociological study of riparian forests in Benin (West Africa)
Natta, A.K. ; Sinsin, B. ; Maesen, L.J.G. van der - \ 2004
Belgian Journal of Botany 136 (2004)2. - ISSN 0778-4031 - p. 109 - 128.
vegetation - classification - ghana
Floristic ordination and classification of riparian forests in Benin were derived from a comprehensive floristic inventory. TWINSPAN classification and DCA analysis of a data set of 818 plant species and 180 releve's yielded 12 plant communities. Importance of waterways, relief, topography, latitude and longitude were the five major environmental gradients that best differentiated riparian plant communities. A syntaxonomic classification of the identified riparian forests plant communities is presented. Riparian forests in Benin belong to the Mitragynetea Schmitz 1963, which is the phytosociological class of hygrophile fresh water forests of tropical Africa. Based on similarities of ecological conditions and floristic composition, we classified the 12 plant communities into 3 orders : Alchornetalia cordifoliae Lebrun 1947, Lanneo-Pseudospondietalia Lebrun & Gilbert 1954 and Pterygotetalia Lebrun & Gilbert 1954
Reduction of starch granule size by expression of an engineered tandem starch-binding domain in potato plants
Ji, Q. ; Oomen, R.J.F.J. ; Vincken, J.P. ; Bolam, D.N. ; Gilbert, H.J. ; Suurs, L.C.J.M. ; Visser, R.G.F. - \ 2004
Plant Biotechnology Journal 2 (2004)3. - ISSN 1467-7644 - p. 251 - 260.
specificity - sequence - cellulose - xylanase - modules - mutant - tissue - gene
Granule size is an important parameter when using starch in industrial applications. An artificial tandem repeat of a family 20 starch-binding domain (SBD2) was engineered by two copies of the SBD derived from Bacillus circulans cyclodextrin glycosyltransferase via the Pro-Thr-rich linker peptice from Xyn10A from Cellulomonas fimi. SBD2 and a single SBD were introduced into the amylose-free potato mutant, amf, using appropriate signal sequences. The accumulation of SBD2 into transgenic starch granules was much higher than that of SBD. In a number of transformants, particularly amfSS3, the starch granules were much smaller than in control plants. The amfSS3 mean granule size was 7.8 mum, compared with 15.2 mum in the control, whereas other starch properties were unaltered. This new starch combines the advantage of the high purity of potato starch with that of the small granule size of other crop species, such as cassava, taro and wheat. This starch may find application in the manufacture of biodegradable plastic films. Both genes were also expressed in Escherichia coli and the affinity for soluble starch of the purified recombinant proteins was determined. SBD2 had an approximately 10-fold higher affinity for starch than SBD, indicating that the two appended SBDs act in synergy when binding to their target polysaccharide ligand.
Adaptation of the CROPGRO growth model to velvet bean (Mucuna pruriens) : II Cultivar evaluation and model testing
Hartkamp, A.D. ; Hoogenboom, G. ; Gilbert, R. ; Benson, T. ; Tarawali, S.A. ; Gijsman, A. ; Bowen, W. ; White, J.W. - \ 2002
Field Crops Research 78 (2002)1. - ISSN 0378-4290 - p. 27 - 40.
Velvet bean (Mucuna pruriens (L.) DC. cv.-group utilis) is widely promoted in tropical and sub-tropical regions as a green manure cover crop that can reduce weed growth and soil erosion and enhance soil fertility. To provide these benefits, the crop must attain rapid ground cover and develop substantial aboveground biomass. To assist biophysical targeting of the crop to environments that can provide adequate growth conditions, the CROPGRO model was adapted to simulate velvet bean growth and development. This paper evaluates the performance of the model for phenology, growth, senescence and N accumulation for multiple locations that represent a range of environmental and agronomic management scenarios. Vegetative development, as described by main stem leaf appearance rate, varied linearly with thermal time. Time to flowering showed departures from the linear photoperiod response used in the model. Additional research is required to determine whether the crop is influenced by factors besides photoperiod and air temperature, especially water and nutrient deficits. The linear response to photoperiod did, however, provide reasonable values for partitioning to vegetative, reproductive and senesced materials. Simulation of nitrogen concentration for various plant components matched observed data. Sensitivity analyses evaluating the ability of the crop to provide ground cover, intercept light and develop adequate growth for soil protection and weed suppression indicated that a mean temperature of over 22 °C and a soil moisture holding capacity of at least 100 mm are required. The CROPGRO model proved to be a reliable decision support tool for guiding analyses of velvet bean response to crop management and environmental conditions. Further research, however, is warranted to improve its predictive capability, especially for phenology.
Engineering of Thermostable Family 1 B-glycosidases for Saccharide Processing
Kaper, T. ; Oost, J. van der; Vos, W.M. de - \ 2002
In: Carbohydrate bioengineering Interdisciplinary Aproaches / Teeri, T.T., Svensson, B., Gilbert, H.J., Feizi, T., Cambridge : Royal Society of Chemistry - p. 135 - 142.
A new family of rhamnogalacturonan lyases contains an enzyme that binds to cellulose
McKie, V.A. ; Vincken, J.P. ; Voragen, A.G.J. ; Broek, L.A.M. van den; Stimson, E. ; Gilbert, H.J. - \ 2001
Biochemical Journal 355 (2001). - ISSN 0264-6021 - p. 167 - 177.
Pseudomonas cellulosa is an aerobic bacterium that synthesizes an extensive array of modular cellulases and hemicellulases, which have a modular architecture consisting of catalytic domains and distinct non-catalytic carbohydrate-binding modules (CBMs). To investigate whether the main-chain-cleaving pectinases from this bacterium also have a modular structure, a library of P. cellulosa genomic DNA, constructed in lZAPII, was screened for pectinase-encoding sequences. A recombinant phage that attacked arabinan, galactan and rhamnogalacturonan was isolated. The encoded enzyme, designated Rgl11A, had a modular structure comprising an N-terminal domain that exhibited homology to Bacillus and Streptomyces proteins of unknown function, a middle domain that exhibited sequence identity to fibronectin-3 domains, and a C-terminal domain that was homologous to family 2a CBMs. Expression of the three modules of the Pseudomonas protein in Escherichia coli showed that its C-terminal module was a functional cellulose-binding domain, and the N-terminal module consisted of a catalytic domain that hydrolysed rhamnogalacturonan-containing substrates. The activity of Rgl11A against apple- and potato-derived rhamnogalacturonan substrates indicated that the enzyme had a strong preference for rhamnogalacturonans that contained galactose side chains, and which were not esterified. The enzyme had an absolute requirement for calcium, a high optimum pH, and catalysis was associated with an increase in absorbance at 235nm, indicating that glycosidic bond cleavage was mediated via a b-elimination mechanism. These data indicate that Rgl11A is a rhamnogalacturonan lyase and, together with the homologous Bacillus and Streptomyces proteins, comprise a new family of polysaccharide lyases. The presence of a family 2a CBM in Rgl11A, and in a P. cellulosa pectate lyase described in the accompanying paper [Brown, Mallen, Charnock, Davies and Black (2001) Biochem. J. 355, 155–165] suggests that the capacity to bind cellulose plays an important role in the activity of main-chain-cleaving Pseudomonas pectinases, in addition to cellulases and hemicellulases.
Can testate amoebae (protozoa) and other micro-organisms help to overcome biogeographic bias in large scale global change research?
Mitchell, E.A.D. ; Gilbert, D. ; Butler, A. ; Grosvernier, P. ; Albinsson, C. ; Rydin, H. ; Heijmans, M.M.P.D. ; Hoosbeek, M.R. ; Greenup, A. ; Foot, J. ; Saarinen, T. ; Vasander, H. - \ 2001
In: Global Change and Protected Areas / Visconti, G., - p. 301 - 310.
klimaatverandering - kooldioxide - vegetatie - micro-organismen - climatic change - carbon dioxide - vegetation - microorganisms
The use of atmospheric dispersion models in risk assessment decision support systems for pesticides
Leeuw, F.A.A.M. de; Pul, W.A.J. van; Berg, F. van den; Gilbert, A.J. - \ 2000
Environmental Monitoring and Assessment 62 (2000)2. - ISSN 0167-6369 - p. 133 - 145.
pesticiden - emissie - luchtverontreiniging - modellen - nederland - beslissingsondersteunende systemen - pesticides - emission - air pollution - models - netherlands - decision support systems
In the evaluation of potentially adverse effects of organic chemicals such as pesticides on the environment the atmosphere may play an important role. After its release to the atmosphere the chemical will be transported/dispersed in the atmosphere andfinally it will be removed either by atmospheric-chemical destruction or by deposition to the underlying soil or surface water. In a risk assessment decision support system both ambient concentrations and deposition fluxes must be known to evaluate the risk of direct exposure (inhalation) or the risk of soil and water contamination caused by deposition. This paper discusses the use of atmospheric dispersion models in such risk assessment decision support systems.
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