Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    '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.

    We have a manual that explains all the features 

Records 1 - 20 / 345

  • help
  • print

    Print search results

  • export
    A maximum of 250 titles can be exported. Please, refine your queryYou can also select and export up to 30 titles via your marked list.
  • alert
    We will mail you new results for this query: q=Ji
Check title to add to marked list
Far-red light during cultivation induces postharvest cold tolerance in tomato fruit
Affandi, Fahrizal Y. ; Verdonk, Julian C. ; Ouzounis, Theoharis ; Ji, Yongran ; Woltering, Ernst J. ; Schouten, Rob E. - \ 2020
Postharvest Biology and Technology 159 (2020). - ISSN 0925-5214
We investigated the role of far-red LED light during cultivation on postharvest cold tolerance in tomato fruit (Solanum lycopersicum cv Moneymaker). Red and blue top LED light, providing 150 μmol m−2 s-1 photo-synthetically active radiation (PAR) at plant height for 16 h daily, was combined with 0, 30 or 50 μmol m−2 s-1 (non-PAR) far-red LED light. Tomatoes were harvested at the mature green or red stage and subjected to cold storage for 0, 5, 10, and 15 d at 4 °C, followed by 20 d shelf-life at 20 °C.
Mature green harvested tomatoes, cultivated with additional far-red light, showed reduced weight loss, less pitting, faster red colour development during shelf-life (when prior long cold stored), and less softening (when prior short or non-cold stored). FR lighting during cultivation likely protects the membrane integrity of MG tomatoes and thus allows uninterrupted lycopene synthesis. Red harvested tomatoes cultivated with additional far-red light were firmer at harvest, showed reduced weight loss and less decay during shelf-life. Less red colouration was observed for red harvested fruits at the start of shelf-life when fruits were prior cold stored, indicative of lycopene breakdown during cold storage. The improved cold tolerance of red harvested fruits grown under additional far-red light is likely due to higher firmness at the start of the shelf-life period with lycopene acting as antioxidant during cold storage. In conclusion, additional far-red light during cultivation improved postharvest cold tolerance for tomatoes harvested at both the green and red maturity stage, and might therefore be suitable to prolong the storage potential of tomato at sub-optimal temperatures.
Protist communities are more sensitive to nitrogen fertilization than other microorganisms in diverse agricultural soils
Zhao, Zhi Bo ; He, Ji Zheng ; Geisen, Stefan ; Han, Li Li ; Wang, Jun Tao ; Shen, Ju Pei ; Wei, Wen Xue ; Fang, Yun Ting ; Li, Pei Pei ; Zhang, Li Mei - \ 2019
Microbiome 7 (2019)1. - ISSN 2049-2618
High-throughput sequencing - Microbiome - Nitrogen fertilizers - Soil protists - Soil type

Background: Agricultural food production is at the base of food and fodder, with fertilization having fundamentally and continuously increased crop yield over the last decades. The performance of crops is intimately tied to their microbiome as they together form holobionts. The importance of the microbiome for plant performance is, however, notoriously ignored in agricultural systems as fertilization disconnects the dependency of plants for often plant-beneficial microbial processes. Moreover, we lack a holistic understanding of how fertilization regimes affect the soil microbiome. Here, we examined the effect of a 2-year fertilization regime (no nitrogen fertilization control, nitrogen fertilization, and nitrogen fertilization plus straw amendment) on entire soil microbiomes (bacteria, fungi, and protist) in three common agricultural soil types cropped with maize in two seasons. Results: We found that the application of nitrogen fertilizers more strongly affected protist than bacterial and fungal communities. Nitrogen fertilization indirectly reduced protist diversity through changing abiotic properties and bacterial and fungal communities which differed between soil types and sampling seasons. Nitrogen fertilizer plus straw amendment had greater effects on soil physicochemical properties and microbiome diversity than nitrogen addition alone. Moreover, nitrogen fertilization, even more together with straw, increased soil microbiome network complexity, suggesting that the application of nitrogen fertilizers tightened soil microbiomes interactions. Conclusions: Together, our results suggest that protists are the most susceptible microbiome component to the application of nitrogen fertilizers. As protist communities also exhibit the strongest seasonal dynamics, they serve as the most sensitive bioindicators of soil changes. Changes in protist communities might have long-term effects if some of the key protist hubs that govern microbiome complexities as top microbiome predators are altered. This study serves as the stepping stone to promote protists as promising agents in targeted microbiome engineering to help in reducing the dependency on exogenous unsustainably high fertilization and pesticide applications.

Towards an integrative understanding of soil biodiversity
Thakur, Madhav P. ; Phillips, Helen R.P. ; Brose, Ulrich ; Vries, Franciska T. De; Lavelle, Patrick ; Loreau, Michel ; Mathieu, Jerome ; Mulder, Christian ; Putten, Wim H. Van der; Rillig, Matthias C. ; Wardle, David A. ; Bach, Elizabeth M. ; Bartz, Marie L.C. ; Bennett, Joanne M. ; Briones, Maria J.I. ; Brown, George ; Decaëns, Thibaud ; Eisenhauer, Nico ; Ferlian, Olga ; Guerra, Carlos António ; König-Ries, Birgitta ; Orgiazzi, Alberto ; Ramirez, Kelly S. ; Russell, David J. ; Rutgers, Michiel ; Wall, Diana H. ; Cameron, Erin K. - \ 2019
Biological Reviews (2019). - ISSN 1464-7931
alpha diversity - beta diversity - biodiversity theory - metacommunity theory - neutral theory - niche theory - spatial scale - species–energy relationship - theory of island biogeography

Soil is one of the most biodiverse terrestrial habitats. Yet, we lack an integrative conceptual framework for understanding the patterns and mechanisms driving soil biodiversity. One of the underlying reasons for our poor understanding of soil biodiversity patterns relates to whether key biodiversity theories (historically developed for aboveground and aquatic organisms) are applicable to patterns of soil biodiversity. Here, we present a systematic literature review to investigate whether and how key biodiversity theories (species–energy relationship, theory of island biogeography, metacommunity theory, niche theory and neutral theory) can explain observed patterns of soil biodiversity. We then discuss two spatial compartments nested within soil at which biodiversity theories can be applied to acknowledge the scale-dependent nature of soil biodiversity.

Synthesis and Thermal Properties of Bio-Based Copolyesters from the Mixtures of 2,5- A nd 2,4-Furandicarboxylic Acid with Different Diols
Thiyagarajan, Shanmugam ; Meijlink, Michael A. ; Bourdet, Aurélie ; Vogelzang, Willem ; Knoop, Rutger J.I. ; Esposito, Antonella ; Dargent, Eric ; Es, Daan S. Van; Haveren, Jacco Van - \ 2019
ACS sustainable chemistry & engineering 7 (2019)22. - ISSN 2168-0485 - p. 18505 - 18516.
activation energy - FDCA isomers - Henkel reaction - mixing law - MT-TGA

Recent works highlighted how interesting are the properties of furan-based polyesters. Most of the attention has been focused on the homopolyester obtained with 2,5-furandicarboxylic acid and ethylene glycol, but other possibilities exist, which could help in tuning the final properties by carefully selecting the nature and proportion of the initial building blocks. This work reports the synthesis and properties (thermal stability, activation energy for thermal decomposition, glass transition temperature, and aptitude to crystallize) of three series of polyesters obtained by combining various amounts of two isomers of furandicarboxylic acid with different linear aliphatic diols, such as ethylene glycol, 1,3-propanediol, and 1,4-butanediol. This approach provided homopolymers and copolymers with high molecular weights, good thermal stability, broad processing windows, and a thermal behavior that can be tuned both in terms of glass transition temperature and crystallinity. In most cases, the mixtures of 2,5- A nd 2,4-isomers obtained during the Henkel disproportionation reaction can be directly used to synthetize furan-based copolyesters with good properties without the downstream processing typically performed to separate the isomers prior to polymerization, which may considerably reduce the time and costs for biomass valorization.

Dietary protein and resistance exercise training for community-dwelling older adults : Intervention adaptation, implementation and effectiveness
Dongen, Ellen J.I. van - \ 2019
Wageningen University. Promotor(en): C.P.G.M. de Groot, co-promotor(en): A. Haveman-Nies; E.L. Doets. - Wageningen : Wageningen University - ISBN 9789463951098 - 247

The number of older adults is increasing worldwide, and more emphasis is placed on aging in place in good health and with good quality of life. The age related loss of muscle mass, strength and function can negatively impact the ability of older adults to live independently and perform activities of daily living. Dietary protein and resistance exercise training are strategies to counteract these age related declines. In this research, we adapted an efficacious clinical intervention combining protein supplementation and resistance exercise to practice, and evaluated the implementation and effectiveness of this intervention in Dutch healthcare practice in a randomised controlled multicentre study. Community-dwelling older adults participated in resistance exercise training under supervision of a physiotherapist, and received counselling by a dietitian to increase their dietary protein intake using protein-rich foods. A moderate support intervention period was added to assist participants in continuing their adapted lifestyle. The intervention was effective in improving aspects of physical functioning, muscle strength and lean body mass as compared to a control group. In addition, the intervention was well received by participants and healthcare professionals, and was perceived feasible to implement in Dutch healthcare practice. The research described in this thesis shows that it is possible to systematically adapt an efficacious lifestyle intervention to practice. Future attention is warranted for ensuring optimal intervention intensity and implementation, achieving long-term intervention success, and specifying the target population in practice.

Global distribution of earthworm diversity
Phillips, Helen R.P. ; Guerra, Carlos A. ; Bartz, Marie L.C. ; Briones, Maria J.I. ; Brown, George ; Crowther, Thomas W. ; Ferlian, Olga ; Gongalsky, Konstantin B. ; Hoogen, Johan Van Den; Krebs, Julia ; Orgiazzi, Alberto ; Routh, Devin ; Schwarz, Benjamin ; Bach, Elizabeth M. ; Bennett, Joanne ; Brose, Ulrich ; Decaëns, Thibaud ; König-Ries, Birgitta ; Loreau, Michel ; Mathieu, Jérôme ; Mulder, Christian ; Putten, Wim H. Van Der; Ramirez, Kelly S. ; Rillig, Matthias C. ; Russell, David ; Rutgers, Michiel ; Thakur, Madhav P. ; Vries, Franciska T. De; Wall, Diana H. ; Wardle, David A. ; Arai, Miwa ; Ayuke, Fredrick O. ; Baker, Geoff H. ; Beauséjour, Robin ; Bedano, José C. ; Birkhofer, Klaus ; Blanchart, Eric ; Blossey, Bernd ; Bolger, Thomas ; Bradley, Robert L. ; Callaham, Mac A. ; Capowiez, Yvan ; Caulfield, Mark E. ; Choi, Amy ; Crotty, Felicity V. ; Dávalos, Andrea ; Diaz Cosin, Darío J. ; Dominguez, Anahí ; Duhour, Andrés Esteban ; Eekeren, Nick Van; Emmerling, Christoph ; Falco, Liliana B. ; Fernández, Rosa ; Fonte, Steven J. ; Fragoso, Carlos ; Franco, André L.C. ; Fugère, Martine ; Fusilero, Abegail T. ; Gholami, Shaieste ; Gundale, Michael J. ; Gutiérrez Lopez, Monica ; Hackenberger, Davorka K. ; Hernández, Luis M. ; Hishi, Takuo ; Holdsworth, Andrew R. ; Holmstrup, Martin ; Hopfensperger, Kristine N. ; Lwanga, Esperanza Huerta ; Huhta, Veikko ; Hurisso, Tunsisa T. ; Iannone, Basil V. ; Iordache, Madalina ; Joschko, Monika ; Kaneko, Nobuhiro ; Kanianska, Radoslava ; Keith, Aidan M. ; Kelly, Courtland A. ; Kernecker, Maria L. ; Klaminder, Jonatan ; Koné, Armand W. ; Kooch, Yahya ; Kukkonen, Sanna T. ; Lalthanzara, H. ; Lammel, Daniel R. ; Lebedev, Iurii M. ; Li, Yiqing ; Jesus Lidon, Juan B. ; Lincoln, Noa K. ; Loss, Scott R. ; Marichal, Raphael ; Matula, Radim ; Moos, Jan Hendrik ; Moreno, Gerardo ; Mor n-Ríos, Alejandro ; Muys, Bart ; Neirynck, Johan ; Norgrove, Lindsey ; Novo, Marta ; Nuutinen, Visa ; Nuzzo, Victoria ; Mujeeb Rahman, P. ; Pansu, Johan ; Paudel, Shishir ; Pérès, Guénola ; Pérez-Camacho, Lorenzo ; Piñeiro, Raúl ; Ponge, Jean François ; Rashid, Muhammad Imtiaz ; Rebollo, Salvador ; Rodeiro-Iglesias, Javier ; Rodríguez, Miguel ; Roth, Alexander M. ; Rousseau, Guillaume X. ; Rozen, Anna ; Sayad, Ehsan ; Schaik, Loes Van; Scharenbroch, Bryant C. ; Schirrmann, Michael ; Schmidt, Olaf ; Schröder, Boris ; Seeber, Julia ; Shashkov, Maxim P. ; Singh, Jaswinder ; Smith, Sandy M. ; Steinwandter, Michael ; Talavera, José A. ; Trigo, Dolores ; Tsukamoto, Jiro ; Valença, Anne W. De; Vanek, Steven J. ; Virto, Iñigo ; Wackett, Adrian A. ; Warren, Matthew W. ; Wehr, Nathaniel H. ; Whalen, Joann K. ; Wironen, Michael B. ; Wolters, Volkmar ; Zenkova, Irina V. ; Zhang, Weixin ; Cameron, Erin K. ; Eisenhauer, Nico - \ 2019
Science 366 (2019)6464. - ISSN 0036-8075 - p. 480 - 485.

Soil organisms, including earthworms, are a key component of terrestrial ecosystems. However, little is known about their diversity, their distribution, and the threats affecting them. We compiled a global dataset of sampled earthworm communities from 6928 sites in 57 countries as a basis for predicting patterns in earthworm diversity, abundance, and biomass. We found that local species richness and abundance typically peaked at higher latitudes, displaying patterns opposite to those observed in aboveground organisms. However, high species dissimilarity across tropical locations may cause diversity across the entirety of the tropics to be higher than elsewhere. Climate variables were found to be more important in shaping earthworm communities than soil properties or habitat cover. These findings suggest that climate change may have serious implications for earthworm communities and for the functions they provide.

A Review on the Potential and Limitations of Recyclable Thermosets for Structural Applications
Post, Wouter ; Susa, Arijana ; Blaauw, Rolf ; Molenveld, Karin ; Knoop, Rutger J.I. - \ 2019
Polymer Reviews (2019). - ISSN 1558-3724
circular economy - dynamic covalent cross-links - polymer matrix - recycling - Thermoset

The outstanding performance of conventional thermosets arising from their covalently cross-linked networks directly results in a limited recyclability. The available commercial or close-to-commercial techniques facing this challenge can be divided into mechanical, thermal, and chemical processing. However, these methods typically require a high energy input and do not take the recycling of the thermoset matrix itself into account. Rather, they focus on retrieving the more valuable fibers, fillers, or substrates. To increase the circularity of thermoset products, many academic studies report potential solutions which require a reduced energy input by using degradable linkages or dynamic covalent bonds. However, the majority of these studies have limited potential for industrial implementation. This review aims to bridge the gap between the industrial and academic developments by focusing on those which are most relevant from a technological, sustainable and economic point of view. An overview is given of currently used approaches for the recycling of thermoset materials, the development of novel inherently recyclable thermosets and examples of possible applications that could reach the market in the near future.

Quantifying feedbacks in the plant-atmosphere-cloud continuum
Sikma, Martin - \ 2019
Wageningen University. Promotor(en): N.P.R. Anten; J.i Vilà-Guerau de Arellano, co-promotor(en): J.B. Evers; B.G. Heusinkveld. - Wageningen : Wageningen University - ISBN 9789463435543 - 128

The main objective of this thesis was to gain insights on the impact of diurnal and local interactions between the vegetation, atmosphere and boundary layer clouds in current and future atmospheres. Special focus was placed on the consequences on moist convection, as it is one of the main uncertainties in the global climate and weather models. Moist convection is strongly influenced by the vegetated surface characteristics, which has consequences on the sub-weekly atmospheric state. In this thesis, a balanced approach is taken, which takes into account local (meters) and short (minutes) dynamic vegetation responses to atmospheric and cloud perturbations, that subsequently influence the atmospheric boundary layer and cloud development.

To deepen our understanding of the processes that act on the smaller scales, a Large-Eddy Simulation (LES) model was employed and coupled with a mechanistic land-surface submodel. The LES model explicitly resolved the various dynamical processes at a scale of 50 m, which has an advantage over the coarser atmospheric models as minimal parametrizations are required. The investigations were based on a combined approach of advanced measurements and numerical experiments. The numerical experiments are based on observations over Western Europe, while for the future atmospheres the numerical experiments were inspired on results from a Free-Air CO2 Enrichment (FACE) experiment in Japan and combined with findings from literature.

By following a systematic approach, our results highlighted the regional effects of a strong plant-atmosphere-cloud coupling (Chapter 2). In low wind and convective situations, a lowering in surface energy fluxes resulted in stabilized cloud development, although there was a distinct response based on the cloud optical properties. With increasing background wind, atmospheric roll vortices forced the cloud population into streets (i.e., parallel strips of clouds alternated by clear sky). As a consequence of an asymmetric stomatal plant response, vegetation streaks arose due to cloud shading that negatively affected the surface energy balance. This result shed light to a new coupling mechanism that constrained cloud development and reduced the in-cloud moisture flux (Chapter 3). To determine whether the plant-atmosphere-cloud coupling could be captured by homogeneous surface responses (i.e., related to a response in a NWP or GCM grid box), we performed simulations that were similar in the domain averaged surface energy, but differed in their response: interactive versus prescribed (Chapter 3). Our findings showed that large misrepresentation of up to 56% occurred in the regional moisture flux when the locality of the dynamic plant responses to atmospheric perturbations was not taken into account. This highlighted the need that these atmospheric flow dependent plant-atmosphere-cloud interactions need to be included in the parameterizations of the coarser NWPs and GCMs.

By analyzing a comprehensive observational FACE dataset of two distinct rice varieties in ambient and elevated CO2 environments (+200 ppm) in Chapter 4, we identified a strong interplay between influencers on the plant-atmosphere interaction. In elevated CO2 environments, the physiological response to this factor became apparent, with warmer and drier in-canopy levels in a more closed and less photosynthetic active canopy, while the opposite was found in a more open and photosynthetic active canopy.

Inspired by our findings of Chapter 4, we simulated and investigated the sensitivity of plant responses to elevations in both air temperature (+2 K) as [CO2] (+200 ppm) in Chapter 5. Our findings showed contrasting responses to elevations in temperature and [CO2] on the surface energy balance and momentum transfer. Elevations in temperature yields enhanced plant transpiration, thus latent heat flux, and reduced the sensible heat flux. As a consequence, the turbulent kinetic energy and buoyancy rates reduced, which caused reductions in cloud cover and mid-tropospheric moisture transport. With elevations in [CO2], a distinct response occurred, leading to higher sensible heat fluxes and lower plant transpiration and latent heat fluxes. With more momentum in the atmospheric boundary layer, clouds were able to become deeper and transport more moisture into the troposphere. When simulating a future atmosphere with both elevations in temperature and [CO2] in Chapter 5, we found an offset in the surface energy balance with nearly identical energy fluxes as compared to current situations. However, the plant physiological state was affected, with reductions in plant transpiration and increased CO2 assimilation.

In conclusion, our results highlight the necessity of small scales and interactions, which require a bottom-up approach to be able to accurately capture the nonlinear plant-atmosphere interactions. Neglecting these interactions cause the coarser global climate and numerical weather prediction models to be liable to misrepresentations when modelling current and future atmospheres.

Far-red radiation increases dry mass partitioning to fruits but reduces Botrytis cinerea resistance in tomato
Ji, Yongran ; Ouzounis, Theoharis ; Courbier, Sarah ; Kaiser, Elias ; Nguyen, Phuong T. ; Schouten, Henk J. ; Visser, Richard G.F. ; Pierik, Ronald ; Marcelis, Leo F.M. ; Heuvelink, Ep - \ 2019
Environmental and Experimental Botany 168 (2019). - ISSN 0098-8472
Botrytis cinerea - Dry mass partitioning - Far red - Growth component analysis - LED lighting - Solanum lycopersicum

The addition of far-red (FR, 700–800 nm) radiation to standard growth light triggers a set of photomorphogenic responses collectively termed shade avoidance syndrome. Recent research showed that additional FR increased fruit yield in greenhouse tomato production. However, the mechanism behind this increase is not clear; nor is it known whether there is a trade-off between growth and defense against plant diseases in tomato under additional FR. The aims of this study were 1) to quantify the effect of additional FR on tomato fruit growth, 2) to explain this effect based on underlying growth components and 3) to examine the FR effect on resistance against the necrotrophic fungus Botrytis cinerea. Tomato (Solanum lycopersicum ‘Moneymaker’) plants were grown for four months with 30 or 50 μmol m−2 s−1 of FR added to 150 μmol m−2 s−1 red + blue or white background LED lighting. Growth and development parameters were recorded, and a growth component analysis was conducted. Bioassays for resistance against B. cinerea were conducted on leaf samples collected from each light treatment. Additional FR increased total fruit dry mass per plant by 26–45%. FR affected multiple growth components, among which the fraction of dry mass partitioned to fruits was the most prominent with a 15–35% increase. Truss appearance rate was increased 11–14% by FR while instantaneous net photosynthesis rate was not affected. FR also resulted in more severe disease symptoms upon infection with B. cinerea. In conclusion, additional FR increases tomato fruit production mainly by increasing dry mass partitioning to fruits, rather than improving photosynthesis or increasing total plant biomass. However, FR also reduces resistance of tomato leaves against B. cinerea.

A methodological framework to embrace soil biodiversity
Geisen, Stefan ; Briones, Maria J.I. ; Gan, Huijie ; Behan-Pelletier, Valerie M. ; Friman, Ville Petri ; Groot, G.A. de; Hannula, S.E. ; Lindo, Zoë ; Philippot, Laurent ; Tiunov, Alexei V. ; Wall, Diana H. - \ 2019
Soil Biology and Biochemistry 136 (2019). - ISSN 0038-0717
Biodiversity - Fauna - Food-webs - Microorganisms - Molecular methods - Soil functions and health

Soils host the vast majority of life on Earth including microorganisms and animals, and supporting all terrestrial vegetation. While soil organisms are pivotal for ecosystem functioning, the assemblages of different biota from a taxonomic and functional perspective, as well as how these different organisms interact, remains poorly known. We provide a brief overview of the taxonomic and functional diversity of all major groups of soil biota across different scales and organism sizes, ranging from viruses to prokaryotes and eukaryotes. This reveals knowledge gaps in relation to all soil biodiversity groups, which are especially evident for viruses, protists, micro- and meso-fauna. We review currently-available methods to study the taxonomic and functional diversity of soil organisms by grouping all commonly-used methods into morphological, biochemical and molecular approaches. We list potentials and limitations of the methods to reveal that there is, as yet, no single method to fully characterize the biodiversity even of a single group of soil biota. Yet, we stress that we now have the methods available to enable scientists to disentangle the taxonomic and functional diversity of virtually all soil organisms. We provide a user-friendly guide to help researchers address a wider variety of soil biodiversity in their studies by discussing and critically analysing the various potentials and limitations of diverse methods to study distinct groups of soil life. We highlight that integrative methodological approaches, ideally in collaborative interactions, are key to advancing our understanding of soil biodiversity, such as the combination of morphological and molecular approaches to overcome method-specific limitations. Together, integrative efforts can provide information on the abundance, biomass, diversity and function of several groups of soil biota simultaneously. This newly-obtained integrative information on soil biodiversity will help to define the importance of soil biodiversity in ecosystem processes, functions, and services, and serve to refine food-web and earth system models.

A Medicago truncatula SWEET transporter implicated in arbuscule maintenance during arbuscular mycorrhizal symbiosis
An, Jianyong ; Zeng, Tian ; Ji, Chuanya ; Graaf, Sanne de; Zheng, Zijun ; Xiao, Ting Ting ; Deng, Xiuxin ; Xiao, Shunyuan ; Bisseling, Ton ; Limpens, Erik ; Pan, Zhiyong - \ 2019
New Phytologist 224 (2019)1. - ISSN 0028-646X - p. 396 - 408.
arbuscular mycorrhiza (AM) - glucose - Medicago truncatula - sugar export - SWEET - symbiosis

Plants form a mutualistic symbiosis with arbuscular mycorrhizal (AM) fungi, which facilitates the acquisition of scarce minerals from the soil. In return, the host plants provide sugars and lipids to its fungal partner. However, the mechanism by which the AM fungi obtain sugars from the plant has remained elusive. In this study we investigated the role of potential SWEET family sugar exporters in AM symbiosis in Medicago truncatula. We show that M. truncatula SWEET1b transporter is strongly upregulated in arbuscule-containing cells compared to roots and localizes to the peri-arbuscular membrane, across which nutrient exchange takes place. Heterologous expression of MtSWEET1b in a yeast hexose transport mutant showed that it mainly transports glucose. Overexpression of MtSWEET1b in M. truncatula roots promoted the growth of intraradical mycelium during AM symbiosis. Surprisingly, two independent Mtsweet1b mutants, which are predicted to produce truncated protein variants impaired in glucose transport, exhibited no significant defects in AM symbiosis. However, arbuscule-specific overexpression of MtSWEET1bY57A/G58D, which are considered to act in a dominant-negative manner, resulted in enhanced collapse of arbuscules. Taken together, our results reveal a (redundant) role for MtSWEET1b in the transport of glucose across the peri-arbuscular membrane to maintain arbuscules for a healthy mutually beneficial symbiosis.

Determination of the equilibrium enthalpy of melting of two-phase semi-crystalline polymers by fast scanning calorimetry
Fosse, Clément ; Bourdet, Aurélie ; Ernault, Estève ; Esposito, Antonella ; Delpouve, Nicolas ; Delbreilh, Laurent ; Thiyagarajan, Shanmugam ; Knoop, Rutger J.I. ; Dargent, Eric - \ 2019
Thermochimica Acta 677 (2019). - ISSN 0040-6031 - p. 67 - 78.
Enthalpy of melting - Fast scanning calorimetry - PBF - PEF - Rigid amorphous fraction

The equilibrium enthalpy of melting ΔHm 0 [J·g−1] is an extrapolated thermodynamic quantity attributed to crystallizable macromolecules and widely used to characterize polymers in their semi-crystalline state, for it allows estimating the degree of crystallinity by direct comparison with the enthalpy of melting obtained from differential scanning calorimetry. ΔHm 0 is typically obtained by cross-comparing the results obtained by at least two techniques. This work proposes a simplified experimental protocol to determine ΔHm 0 by the use of Fast Scanning Calorimetry (FSC). This approach applies to any crystallizable polymer for which a specific microstructure can be obtained (i.e. a two-phase semi-crystalline microstructure with a negligible amount of rigid amorphous fraction) and that can also be quenched to its fully amorphous state. Such a two-phase microstructure can be obtained on nanoscale samples through an annealing process performed in situ on the FSC sensor at crystallization temperatures as close as possible to the melting temperature. The enthalpy of melting is then evaluated from the two-phase model for different crystallization times (i.e. different crystallinities) and the ΔHm 0 is obtained by extrapolating the data to the 100% crystalline state. This procedure was applied on samples whose ΔHm 0 values are already available in the literature, but also on more recent biobased polyesters whose thermal properties are still under investigations.

Toll-like receptors TLR2 and TLR4 block the replication of pancreatic β cells in diet-induced obesity
Ji, Yewei ; Sun, Shengyi ; Shrestha, Neha ; Darragh, Laurel B. ; Shirakawa, Jun ; Xing, Yuan ; He, Yi ; Carboneau, Bethany A. ; Kim, Hana ; An, Duo ; Ma, Minglin ; Oberholzer, Jose ; Soleimanpour, Scott A. ; Gannon, Maureen ; Liu, Chengyang ; Naji, Ali ; Kulkarni, Rohit N. ; Wang, Yong ; Kersten, Sander ; Qi, Ling - \ 2019
Nature Immunology 20 (2019)6. - ISSN 1529-2908 - p. 677 - 686.

Consumption of a high-energy Western diet triggers mild adaptive β cell proliferation to compensate for peripheral insulin resistance; however, the underlying molecular mechanism remains unclear. In the present study we show that the toll-like receptors TLR2 and TLR4 inhibited the diet-induced replication of β cells in mice and humans. The combined, but not the individual, loss of TLR2 and TLR4 increased the replication of β cells, but not that of α cells, leading to enlarged β cell area and hyperinsulinemia in diet-induced obesity. Loss of TLR2 and TLR4 increased the nuclear abundance of the cell cycle regulators cyclin D2 and Cdk4 in a manner dependent on the signaling mediator Erk. These data reveal a regulatory mechanism controlling the proliferation of β cells in diet-induced obesity and suggest that selective targeting of the TLR2/TLR4 pathways may reverse β cell failure in patients with diabetes.

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.

Inter-provincial electricity transmissions’ co-benefit of national water savings in China
Liao, Xiawei ; Chai, Li ; Jiang, Yu ; Ji, Junping ; Zhao, Xu - \ 2019
Journal of Cleaner Production 229 (2019). - ISSN 0959-6526 - p. 350 - 357.
Co-benefit - Electricity transmission - Water conservation - Water-energy nexus

Interprovincial electricity transmissions have been utilised in China to overcome the country's imbalanced social-economic development and resource endowments. A bottom-up technology-based model is adopted to estimate water uses in electricity-exporting provinces to produce the transmitted electricity as well as opportunistic water savings in the receiving provinces. The results highlight that, in 2014, on a national scale, electricity transmissions generated co-benefit of saving 20.1 billion m³ of water nationally due to the electric power sector's water productivity differences in the exporting and importing provinces. Taking regional water stresses into account, 10.98 billion m³ of national scarce water saving is realized through electricity transmissions. Moreover, electricity transmissions by China's proposed 12 future transmission lines are expected to use additional 3.22 billion m³ of water in the electricity-exporting provinces. As more water-intensive technologies, e.g. open-loop cooling, are more commonly utilised in the electricity-receiving provinces, a total amount of 16.97 billion m³ of water use will be avoided nationally. Water-use efficiency for power production should be improved in all regions. Transmitted power imports should still be encouraged in water-scarce regions to alleviate their water stresses while power exports should be shifted away from water-stressed regions to water-abundant ones. Energy transformation by utilising gas-fired capacity and hydropower in water-abundant Southern China could be advanced.

Water footprint of the energy sector in China's two megalopolises
Liao, Xiawei ; Zhao, Xu ; Jiang, Yu ; Liu, Yu ; Yi, Yujun ; Tillotson, Martin R. - \ 2019
Ecological Modelling 391 (2019). - ISSN 0304-3800 - p. 9 - 15.
Jing-Jin-Ji - Urban - Water footprint - Water-for-energy nexus - Yangtze Delta

Using a consumption-based Multi-Regional Input-Output (MRIO) model, we investigate the distinctive characteristics, self-efficiency or external dependency, of energy demand's water footprint in China's two biggest and fastest developing megalopolises. We find that energy demand water footprint in the Jing-Jin-Ji and the Yangtze Delta amounted to 2.41 and 9.59 billion m³of water withdrawal respectively in 2010, of which 848.06 and 973.91 million m³was consumed. Among all energy products, electricity contributed the largest share to the energy sector's water footprint in both regions. The sectoral distribution of water footprint in the upstream supply chain differed by region. Most significantly, the agricultural sector accounted for more than 30% of water consumption footprint. In addition to water used locally, final energy demands in these two regions induced external water footprint beyond their administrative boundaries. The Jing-Jin-Ji region's energy sector had a smaller water footprint compared to the water-abundant Yangtze Delta region. However, external water footprint occupied a larger proportion in the former. Such divergence can be attributed to the distinctive water endowments and water-using technologies utilized in their respective energy sectors. Bespoke urban governance and policies tailored to local resource and technology portfolios are recommended for different urban agglomeration energy and water flows.

Effects of pre-emulsification by three food-grade emulsifiers on the properties of emulsified surimi sausage
Liu, Xiangyu ; Ji, Lei ; Zhang, Tao ; Xue, Yong ; Xue, Changhu - \ 2019
Journal of Food Engineering 247 (2019). - ISSN 0260-8774 - p. 30 - 37.
Emulsification process - Emulsified surimi sausage - Peanut oil - Textural properties

In this study, we investigated the effects of peanut oil pre-emulsification by three food-grade emulsifiers (soy protein isolate (SPI), konjac glucomannan (KGM), and acetylated distarch phosphate (ADSP)) on the properties of emulsified surimi sausage. TPA tests showed that KGM comprehensively improved sausage texture. SPI reduced the emulsified sausage hardness from 131.37 ± 3.12 N to 111.13 ± 1.23 N and ADSP reduced the adhesiveness of the product from −0.57 ± 0.05 to −0.37 ± 0.04. The water holding capacity, emulsification stability, and whiteness properties improved significantly after adding the pre-emulsified peanut oil (p < 0.05). Rheology experiments and particle size measurements revealed competitive emulsification between myosin and each emulsifier. Finally, more uniform distributions of oil droplets in the SPI, KGM, and ADSP groups were observed by optical microscopy. Overall, KGM is suggested as the ideal candidate for the pre-emulsification of peanut oil for emulsified surimi sausage products.

A new satellite-based indicator to identify spatiotemporal foraging areas for herbivorous waterfowl
Wei, Jie ; Xin, Qinchuan ; Ji, Luyan ; Gong, Peng ; Si, Yali - \ 2019
Ecological Indicators 99 (2019). - ISSN 1470-160X - p. 83 - 90.
Distribution - Geese - MODIS - Nutrient biomass - Plant phenology - Yangtze River floodplain

The distribution of food resources is a key factor in habitat selection. Herbivorous waterfowl prefer early-stage growing plants (from the onset of plant growth to the peak in nutrient biomass) as these offer higher energy intake rates. This plant development stage is not fully captured by commonly used satellite-derived vegetation indicators, which focus on plant biomass (e.g., Enhanced Vegetation Index, EVI) or active plant growth (e.g., the differential EVI between current and a previous date, diffEVI). To improve mapping suitable grazing areas for herbivorous waterfowl, we propose a new satellite-based plant growth indicator of early-stage plant growth (ESPG). We hypothesize that herbivorous waterfowl prefer plants at an early development stage during the growing season and select plants with a relatively later end of ESPG during the non-growing season. We use satellite tracking data of 20 greater white-fronted geese (Anser albifrons) wintering in the Yangtze River floodplain to validate our predictions. We build generalized linear models for goose distributions during the growing and non-growing seasons and compare the performance of ESPG to commonly used plant growth indictors (EVI and diffEVI). During the growing season, ESPG can explain 53% of variation in the goose distribution, outperforming EVI (27%) and diffEVI (34%). During the non-growing season, only the end of ESPG significantly influences goose distribution, explaining 25% of the variance (ESPG: AUC = 0.78; EVI: AUC = 0.58; diffEVI: AUC = 0.58). The newly-developed plant growth indicator ESPG could be used to improve models of herbivorous waterfowl distributions and hence support efforts toward waterfowl conservation and wetland management.

Long-term effects of wild ungulates on the structure, composition and succession of temperate forests
Ramirez Chiriboga, J.I. ; Jansen, P.A. ; Ouden, J. den; Goudzwaard, L. ; Poorter, L. - \ 2019
Forest Ecology and Management 432 (2019). - ISSN 0378-1127 - p. 478 - 488.
Ungulates in temperate regions are increasing in range and abundance, leading to concerns that browsing and trampling reach levels that hamper tree recruitment and forest regeneration. However, studies that actually quantify the long-term effects of ungulates on forest succession are scarce. Here, we use a chronosequence of ungulate exclosures (fenced) and control (unfenced) plots to assess the long-term effects of ungulates on forest structure, diversity and litter depth in forests on poor sandy soils at the Veluwe, the Netherlands, which have moderate ungulate densities ( = 13.6 ungulates km−2). We surveyed the vegetation in 27 paired fenced and unfenced plots that ranged from 1 to 33 years old, and measured seven variables to characterize forest structure (stem density, canopy cover and understory vegetation cover), composition (Shannon diversity, species richness and conifer proportion) and leaf litter depth. We found on average that fencing compared to unfencing reduced understory vegetation cover (fenced = 64.3 ± 20.2%, unfenced = 80.3 ± 19.4%), increased canopy cover (fenced = 47.4 ± 30.1%, unfenced = 29.3 ± 21.1%), tree species richness (fenced = 4.5 ± 1.3 spp., unfenced = 2.7 ± 1.2 spp.), tree Shannon diversity (fenced = 1.1 ± 0.3 index, unfenced = 0.7 ± 0.3 index) and litter layer depth (fenced = 4.4 ± 1.4 cm, unfenced = 2.4 ± 1.1 cm). While fenced plots developed woody vegetation with palatable broadleaved species such as Betula pendula, Betula pubescens, Prunus serotina, and Quercus robur, unfenced plots were not associated with any particular tree species. Our results show that current ungulate densities in this system have pronounced long-term effects on forest structure, composition and litter depth, implying that ungulates can slow down natural succession of temperate forest, from light demanding to shade tolerant species, by keeping the system in an arrested state consisting of light demanding species.
Public-private partnerships as systemic agricultural innovation policy instruments : Assessing their contribution to innovation system function dynamics
Hermans, F.L.P. ; Geerling-Eiff, F.A. ; Potters, J.I. ; Klerkx, L.W.A. - \ 2019
NJAS Wageningen Journal of Life Sciences 88 (2019). - ISSN 1573-5214 - p. 76 - 95.
This paper addresses the question how public-private partnerships function as systemic innovation policy instruments within agricultural innovation systems. Public-private partnerships are a popular government tool to promote innovations. However, the wide ranging nature of PPPs make it difficult to assess their effects beyond the direct impacts they generate for the partners. This paper broadens the discussion on the evaluation of PPPs beyond the organisational and financial benefits of the actors involved, and assesses their contribution to the functioning of the innovation system itself. In this paper, we utilise an innovation system perspective that focusses on how PPPs influence the dynamic interplay of innovation system functions and how these functions form a set of feedback loops that constitute an ‘innovation motor’. We compare the innovation history of four cases that differ in their strategic policy goals, either working on agricultural sustainability, or on the international competitiveness in the Dutch agricultural sector. The results show the strengths and weaknesses of different types of public-private partnerships as systemic instruments and their capability to orchestrate other types of innovation policy instruments
Check title to add to marked list
<< previous | next >>

Show 20 50 100 records per page

Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.