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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    Bladderworts, the smallest known suction feeders, generate inertia-dominated flows to capture prey
    Müller, Ulrike K. ; Berg, Otto ; Schwaner, Janneke M. ; Brown, Matthew D. ; Li, Gen ; Voesenek, Cees J. ; Leeuwen, Johan L. van - \ 2020
    New Phytologist (2020). - ISSN 0028-646X
    carnivorous plants - functional morphology - plant biomechanics - suction feeding - Utricularia australis - Utricularia gibba

    Aquatic bladderworts (Utricularia gibba and U. australis) capture zooplankton in mechanically triggered underwater traps. With characteristic dimensions less than 1 mm, the trapping structures are among the smallest known to capture prey by suction, a mechanism that is not effective in the creeping-flow regime where viscous forces prevent the generation of fast and energy-efficient suction flows. To understand what makes suction feeding possible on the small scale of bladderwort traps, we characterised their suction flows experimentally (using particle image velocimetry) and mathematically (using computational fluid dynamics and analytical mathematical models). We show that bladderwort traps avoid the adverse effects of creeping flow by generating strong, fast-onset suction pressures. Our findings suggest that traps use three morphological adaptations: the trap walls' fast release of elastic energy ensures strong and constant suction pressure; the trap door's fast opening ensures effectively instantaneous onset of suction; the short channel leading into the trap ensures undeveloped flow, which maintains a wide effective channel diameter. Bladderwort traps generate much stronger suction flows than larval fish with similar gape sizes because of the traps' considerably stronger suction pressures. However, bladderworts' ability to generate strong suction flows comes at considerable energetic expense.

    Urinary Excretion of N1-Methylnicotinamide and N1-Methyl-2-Pyridone-5-Carboxamide and Mortality in Kidney Transplant Recipients
    Deen, Carolien P.J. ; Veen, Anna van der; Gomes-Neto, António W. ; Geleijnse, Johanna M. ; Borgonjen van den Berg, Karin J. ; Heiner-Fokkema, M.R. ; Kema, Ido P. ; Bakker, Stephan J.L. - \ 2020
    Nutrients 12 (2020)7. - ISSN 2072-6643
    dietary intake - mortality - N1-methyl-2-pyridone-5-carboxamide - N1-methylnicotinamide - niacin status - renal transplantation - tryptophan - urinary excretion - vitamin B3

    It is unclear whether niacin nutritional status is a target for improvement of long-term outcome after renal transplantation. The 24-h urinary excretion of N1-methylnicotinamide (N1-MN), as a biomarker of niacin status, has previously been shown to be negatively associated with premature mortality in kidney transplant recipients (KTR). However, recent evidence implies higher enzymatic conversion of N1-MN to N1-methyl-2-pyridone-5-carboxamide (2Py) in KTR, therefore the need exists for interpretation of both N1-MN and 2Py excretion for niacin status assessment. We assessed niacin status by means of the 24-h urinary excretion of the sum of N1-MN and 2Py (N1-MN + 2Py), and its associations with risk of premature mortality in KTR. N1-MN + 2Py excretion was measured in a longitudinal cohort of 660 KTR with LS-MS/MS. Prospective associations of N1-MN + 2Py excretion were investigated with Cox regression analyses. Median N1-MN + 2Py excretion was 198.3 (155.9-269.4) µmol/day. During follow-up of 5.4 (4.7-6.1) years, 143 KTR died, of whom 40 due to an infectious disease. N1-MN + 2Py excretion was negatively associated with risk of all-cause mortality (HR 0.61; 95% CI 0.47-0.79; p < 0.001), and infectious mortality specifically (HR 0.47; 95% CI 0.29-0.75; p = 0.002), independent of potential confounders. Secondary analyses showed effect modification of hs-CRP on the negative prospective association of N1-MN + 2Py excretion, and sensitivity analyses showed negative and independent associations of N1-MN and 2Py excretion with risk of all-cause mortality separately. These findings add further evidence to niacin status as a target for nutritional strategies for improvement of long-term outcome in KTR.

    Systemic colonization of potato plants resulting from potato haulm inoculation with Dickeya solani or Pectobacterium parmentieri
    Kastelein, P. ; Forch, M.G. ; Krijger, M.C. ; Zouwen, P.S. van der; Berg, W. van den; Wolf, J.M. van der - \ 2020
    Canadian Journal of Plant Pathology = Revue Canadienne de Phytopathologie (2020). - ISSN 0706-0661 - p. 1 - 15.
    blackleg - Confocal laser scanning microscopy - fluorescence microscopy - GFP-tagged strains - haulm destruction - leaf wounding - slow wilt
    In two glasshouse experiments, colonization of potato (Solanum tuberosum L.) plants by the bacterial pathogens Dickeya solani and Pectobacterium parmentieri was studied after leaf infection. Leaves, whether or not artificially wounded, were spray-inoculated with various densities of green-fluorescent protein tagged strains of the pathogens, avoiding contamination of soil during inoculation. Microscopy analysis indicated that both pathogens were able to penetrate and colonize hydathodes, stomata and wounds of inoculated leaves. Dickeya solani was detected at 42 days after inoculation in leaves, stems, stolons and occasionally in tubers, whereas P. parmentieri was restricted to leaves, stems and stolons, and could not be detected in tubers. The infection percentage was higher for plants with wounded leaves than for plants with untouched leaves, and higher at higher inoculum densities. Nevertheless, infection of leaves could also occur at low densities of D. solani (102 cfu mL−1). We further investigated the risks for translocation of the pathogens from infected haulms through soil into progeny tubers after haulm destruction. In a glasshouse experiment, populations of the pathogens increased in haulms in the first week after chemical or mechanical destruction, but decreased in the second week. For P. parmentieri, transmission occurred from destroyed haulms via soil into progeny tubers in soil, but not for D. solani.
    Verticillium Wilt in Oilseed Rape—the Microbiome is Crucial for Disease Outbreaks as Well as for Efficient Suppression
    Rybakova, Daria ; Wikström, M. ; Birch-Jensen, Fia ; Postma, J. ; Ehlers, Ralf Uno ; Schuck, Maria ; Kollmann, René ; Köhl, J. ; Berg, Gabriele - \ 2020
    Plants 9 (2020)7. - ISSN 2223-7747
    Microbiome management is a promising way to suppress verticillium wilt, a severe disease in Brassica caused by Verticillium longisporum. In order to improve current biocontrol strategies, we compared bacterial Verticillium antagonists in different assays using a hierarchical selection and evaluation scheme, and we integrated outcomes of our previous studies. The result was strongly dependent on the assessment method chosen (in vitro, in vivo, in situ), on the growth conditions of the plants and their genotype. The most promising biocontrol candidate identified was a Brassica endophyte Serratia plymuthica F20. Positive results were confirmed in field trials and by microscopically visualizing the three-way interaction. Applying antagonists in seed treatment contributes to an exceptionally low ecological footprint, supporting efficient economic and ecological solutions to controlling verticillium wilt. Indigenous microbiome, especially soil and seed microbiome, has been identified as key to understanding disease outbreaks and suppression. We suggest that verticillium wilt is a microbiome-driven disease caused by a reduction in microbial diversity within seeds and in the soil surrounding them. We strongly recommend integrating microbiome data in the development of new biocontrol and breeding strategies and combining both strategies with the aim of designing healthy microbiomes, thus making plants more resilient toward soil-borne pathogens.
    Effects and moderators of coping skills training on symptoms of depression and anxiety in patients with cancer : Aggregate data and individual patient data meta-analyses
    Buffart, L.M. ; Schreurs, M.A.C. ; Abrahams, H.J.G. ; Kalter, J. ; Aaronson, N.K. ; Jacobsen, P.B. ; Newton, R.U. ; Courneya, K.S. ; Armes, J. ; Arving, C. ; Braamse, A.M. ; Brandberg, Y. ; Dekker, J. ; Ferguson, R.J. ; Gielissen, M.F. ; Glimelius, B. ; Goedendorp, M.M. ; Graves, K.D. ; Heiney, S.P. ; Horne, R. ; Hunter, M.S. ; Johansson, B. ; Northouse, L.L. ; Oldenburg, H.S. ; Prins, J.B. ; Savard, J. ; Beurden, M. van; Berg, S.W. van den; Brug, J. ; Knoop, H. ; Verdonck-de Leeuw, I.M. - \ 2020
    Clinical Psychology Review 80 (2020). - ISSN 0272-7358
    (individual patient data) meta-analysis - Anxiety - Coping skills training - Depression - Neoplasm - Psychosocial care

    Purpose: This study evaluated the effects of coping skills training (CST) on symptoms of depression and anxiety in cancer patients, and investigated moderators of the effects. Methods: Overall effects and intervention-related moderators were studied in meta-analyses of pooled aggregate data from 38 randomized controlled trials (RCTs). Patient-related moderators were examined using linear mixed-effect models with interaction tests on pooled individual patient data (n = 1953) from 15 of the RCTs. Results: CST had a statistically significant but small effect on depression (g = −0.31,95% confidence interval (CI) = −0.40;-0.22) and anxiety (g = −0.32,95%CI = -0.41;-0.24) symptoms. Effects on depression symptoms were significantly larger for interventions delivered face-to-face (p =.003), led by a psychologist (p =.02) and targeted to patients with psychological distress (p =.002). Significantly larger reductions in anxiety symptoms were found in younger patients (pinteraction < 0.025), with the largest reductions in patients <50 years (β = −0.31,95%CI = -0.44;-0.18) and no significant effects in patients ≥70 years. Effects of CST on depression (β = −0.16,95%CI = -0.25;-0.07) and anxiety (β = −0.24,95%CI = -0.33;-0.14) symptoms were significant in patients who received chemotherapy but not in patients who did not (pinteraction < 0.05). Conclusions: CST significantly reduced symptoms of depression and anxiety in cancer patients, and particularly when delivered face-to-face, provided by a psychologist, targeted to patients with psychological distress, and given to patients who were younger and received chemotherapy.

    Litter share and clay content determine soil restoration effects of rich litter tree species in forests on acidified sandy soils
    Desie, Ellen ; Vancampenhout, Karen ; Berg, Leon van den; Nyssen, Bart ; Weijters, Maaike ; Ouden, Jan den; Muys, Bart - \ 2020
    Forest Ecology and Management 474 (2020). - ISSN 0378-1127
    Black cherry - Clay content - Litter quality - Nutrient cycling - Soil acidification - Soil restoration

    Many West-European forests are located on degraded and acidified soils. Soil acidification has resulted in hampered ecosystem functioning and lower delivery of ecosystem services. Forest management, particularly the choice of tree species, can accelerate or counteract soil acidification by the quality of litter input. The positive impact of so called ‘rich litter’ on the soil nutrient status and belowground ecosystem functioning has already been evidenced in common gardens. Here, we evaluate the effect of the rich litter species black cherry (Prunus serotina Ehrh.) in mixed forest stands dominated by pedunculate oak (Quercus robur L.). We study the effects using a replicated set-up of 10 established forest stands (age 30 to 90) in Belgium, the Netherlands and Germany along an edaphic gradient in sandy soils on Pleistocene aeolian deposits. We hypothesize that black cherry has a positive effect on the soil nutrient status and aim to answer the following research questions: (i) does admixture of black cherry increase soil pH and base saturation? (ii) what proportion of rich litter admixture is needed in a poor litter matrix to observe significant improvement of the soil nutrient status? and (iii) does the magnitude of the rich litter effect interact with initial soil properties? The results of this study indicate that admixture of black cherry enhances the forest floor turnover and enriches topsoil chemical conditions significantly. Thickness of the litter layer decreases from a mean of 7 cm under oak to a mean of 4.5 cm under cherry and correspondingly base saturation increases to a maximum of 25%, NO3 concentration to 26 mg/mg and organic matter content to 8%. However, large shares of rich litter admixture (>30% basal area) are needed to improve topsoil conditions. Moreover, we find that rich litter effects are more pronounced on sandy soils with higher fine particle (loam + clay) content. This suggests that the actual impact of restoration efforts in acidified forest soils is a product of the trinity “litter quality – litter share – site quality”.

    Pesticide lifecycle management in agriculture and public health : Where are the gaps?
    Berg, Henk van den; Gu, Baogen ; Grenier, Beatrice ; Kohlschmid, Eva ; Al-Eryani, Samira ; Silva Bezerra, Haroldo Sergio da; Nagpal, Bhupender N. ; Chanda, Emmanuel ; Gasimov, Elkhan ; Velayudhan, Raman ; Yadav, Rajpal S. - \ 2020
    Science of the Total Environment 742 (2020). - ISSN 0048-9697
    Insecticide resistance - Lifecycle management - Pest control - Pesticide management - Risk reduction - Vector control

    Pesticide lifecycle management encompasses a range of elements from legislation, regulation, manufacturing, application, risk reduction, monitoring, and enforcement to disposal of pesticide waste. A survey was conducted in 2017–2018 to describe the contemporary global status of pesticide lifecycle management, to identify where the gaps are found. A three-tiered questionnaire was distributed to government entities in 194 countries. The response rate was 29%, 27% and 48% to the first, second and third part of the questionnaire, respectively. The results showed gaps for most of the selected indicators of pesticide management, suggesting that pesticide efficacy and safety to human health and the environment are likely being compromised at various stages of the pesticide lifecycle, and at varying degrees across the globe. Low-income countries generally had the highest incidence of gaps. Particular shortcomings were deficiencies in pesticide legislation, inadequate capacity for pesticide registration, protection against occupational exposure to pesticides, consumer protection against residues in food, and environmental protection against pesticide contamination. Policy support for, and implementation of, pesticide use-reduction strategies such as integrated pest management and integrated vector management has been inadequate across regions. Priority actions for structural improvement in pesticide lifecycle management are proposed, including pesticide use-reduction strategies, targeted interventions, and resource mobilization.

    Een uniek project, een unieke samenwerking. De governance van Marker Wadden ontleed : Rapportage MEP Adaptieve Governance Marker Wadden
    IJff, Stéphanie ; Willems, Jannes ; Berg, Niels van den; Nuesink, Nienke ; Kuindersma, Wiebren ; Veraart, Jeroen ; Duijn, Mike ; Ellen, Gerald Jan - \ 2020
    Delft : Deltares - 48
    NUcheckt: Wat we weten over de risico's van onkruidverdelger Roundup. Fact check glyfosaat
    Lotz, Bert ; Berg, Martin van den; Geissen, Violette - \ 2020
    Microbiome definition re-visited: old concepts and new 1challenges
    Berg, Gabriele ; Rybakova, Daria ; Fischer, Doreen ; Cernava, Tomislav ; Champomier Vergès, Marie-Christine ; Charles, Trevor ; Chen, Xiaoyulong ; Cocolin, Luca ; Eversole, Kellye ; Overbeek, L.S. van - \ 2020
    Microbiome 8 (2020). - ISSN 2049-2618
    The field of microbiome research has evolved rapidly over the past few decades and has become a topic of great scientific and public interest. As a result of this rapid growth in interest covering different fields, we are lacking a clear commonly agreed definition of the term “microbiome.” Moreover, a consensus on best practices in microbiome research is missing. Recently, a panel of international experts discussed the current gaps in the frame of the European-funded MicrobiomeSupport project. The meeting brought together about 40 leaders from diverse microbiome areas, while more than a hundred experts from all over the world took part in an online survey accompanying the workshop. This article excerpts the outcomes of the workshop and the corresponding online survey embedded in a short historical introduction and future outlook. We propose a definition of microbiome based on the compact, clear, and comprehensive description of the term provided by Whipps et al. in 1988, amended with a set of novel recommendations considering the latest technological developments and research findings. We clearly separate the terms microbiome and microbiota and provide a comprehensive discussion considering the composition of microbiota, the heterogeneity and dynamics of microbiomes in time and space, the stability and resilience of microbial networks, the definition of core microbiomes, and functionally relevant keystone species as well as co-evolutionary principles of microbe-host and inter-species interactions within the microbiome. These broad definitions together with the suggested unifying concepts will help to improve standardization of microbiome studies in the future, and could be the starting point for an integrated assessment of data resulting in a more rapid transfer of knowledge from basic science into practice. Furthermore, microbiome standards are important for solving new challenges associated with anthropogenic-driven changes in the field of planetary health, for which the understanding of microbiomes might play a key role.
    Phenotypic and lifestyle determinants of HbA1c in the general population – the Hoorn study
    Wisgerhof, Willem ; Ruijgrok, Carolien ; Braver, Nicole R. Den; Borgonjen—van Den Berg, Karin J. ; Heijden, Amber A.W.A. Van Der; Elders, Petra J.M. ; Beulens, Joline W.J. ; Alssema, Marjan - \ 2020
    PLoS ONE 15 (2020)6. - ISSN 1932-6203

    Aim To investigate the relative contribution of phenotypic and lifestyle factors to HbA1c, independent of fasting plasma glucose (FPG) and 2h post-load glucose (2hPG), in the general population. Methods The study populations included 2309 participants without known diabetes from the first wave of the Hoorn Study (1989) and 2619 from the second wave (2006). Multivariate linear regression models were used to analyze the relationship between potential determinants and HbA1c in addition to FPG and 2hPG. The multivariate model was derived in the first wave of the Hoorn Study, and replicated in the second wave. Results In both cohorts, independent of FPG and 2hPG, higher age, female sex, larger waist circumference, and smoking were associated with a higher HbA1c level. Larger hip circumference, higher BMI, higher alcohol consumption and vitamin C intake were associated with a lower HbA1c level. FPG and 2hPG together explained 41.0% (first wave) and 53.0% (second wave) of the total variance in HbA1c. The combination of phenotypic and lifestyle determinants additionally explained 5.7% (first wave) and 3.9% (second wave). Conclusions This study suggests that, independent of glucose, phenotypic and lifestyle factors are associated with HbA1c, but the contribution is relatively small. These findings contribute to a better understanding of the low correlation between glucose levels and HbA1c in the general population.

    Characterisation of anopheline larval habitats in southern Malawi
    Gowelo, Steven ; Chirombo, James ; Koenraadt, Constantianus J.M. ; Mzilahowa, Themba ; Berg, Henk van den; Takken, Willem ; McCann, Robert S. - \ 2020
    Acta Tropica 210 (2020). - ISSN 0001-706X
    Habitat characterization - Larval ecology - Malaria mosquito

    Introduction: Increasing the knowledgebase of anopheline larval ecology could enable targeted deployment of malaria control efforts and consequently reduce costs of implementation. In Malawi, there exists a knowledge gap in anopheline larval ecology and, therefore, basis for targeted deployment of larval source management (LSM) for malaria control, specifically larvicides. We set out to characterize anopheline larval habitats in the Majete area of Malawi on the basis of habitat ecology and anopheline larval productivity to create a basis for larval control initiatives in the country. Methods: Longitudinal surveys were conducted in randomly selected larval habitats over a period of fifteen months in Chikwawa district, southern Malawi. Biotic and abiotic parameters of the habitats were modelled to determine their effect on the occurrence and densities of anopheline larvae. Results: Seventy aquatic habitats were individually visited between 1-7 times over the study period. A total of 5,123 immature mosquitoes (3,359 anophelines, 1,497 culicines and 267 pupae) were collected. Anopheline and culicine larvae were observed in sympatry in aquatic habitats. Of the nine habitat types followed, dams, swamps, ponds, borehole runoffs and drainage channels were the five most productive habitat types for anopheline mosquitoes. Anopheline densities were higher in aquatic habitats with bare soil making up part of the surrounding land cover (p<0.01) and in aquatic habitats with culicine larvae (p<0.01) than in those surrounded by vegetation and not occupied by culicine larvae. Anopheline densities were significantly lower in highly turbid habitats than in clearer habitats (p<0.01). Presence of predators in the aquatic habitats significantly reduced the probability of anopheline larvae being present (p=0.04). Conclusions: Anopheline larval habitats are widespread in the study area. Presence of bare soil, culicine larvae, predators and the level of turbidity of water are the main determinants of anopheline larval densities in aquatic habitats in Majete, Malawi. While the most productive aquatic habitats should be prioritised, for the most effective control of vectors in the area all available aquatic habitats should be targeted, even those that are not characterized by the identified predictors. Further research is needed to determine whether targeted LSM would be cost-effective when habitat characterisation is included in cost analyses and to establish what methods would make the characterisation of habitats easier.

    Endo-1,3(4)-β-glucanase-treatment of oat β-glucan enhances fermentability by infant fecal microbiota, stimulates dectin-1 activation and attenuates inflammatory responses in immature dendritic cells
    Akkerman, Renate ; Logtenberg, Madelon J. ; An, Ran ; Berg, Marco A. Van Den; Haan, Bart J. de; Faas, Marijke M. ; Zoetendal, Erwin ; Vos, Paul de; Schols, Henk A. - \ 2020
    Nutrients 12 (2020)6. - ISSN 2072-6643
    Cytokine production - Dendritic cells - In vitro fermentation - Infant formula - Microbiota - Oat β-Glucan

    Background: Non-digestible carbohydrates are added to infant formula to mimic the effects of human milk oligosaccharide by acting as prebiotics and stimulating the immune system. Although not yet used in infant formulas, β-glucans are known to have beneficial health effects, and are therefore of potential interest for supplementation. Methods and results: We investigated the in vitro fermentation of native and endo-1,3(4)-β-glucanase-treated oat β-glucan using pooled fecal inocula of 2-and 8-week-old infants. While native oat β-glucan was not utilized, both inocula specifically utilized oat β-glucan oligomers containing β(1→4)-linkages formed upon enzyme treatment. The fermentation rate was highest in the fecal microbiota of 2-week-old infants, and correlated with a high lactate production. Fermentation of media supplemented with native and enzyme-treated oat β-glucans increased the relative abundance of Enterococcus and attenuated proinflammatory cytokine production (IL-1β, IL-6, TNFα) in immature dendritic cells. This attenuating effect was more pronounced after enzyme treatment. This attenuation might result from the enhanced ability of fermented oat β-glucan to stimulate Dectin-1 receptors. Conclusion: Our findings demonstrate that endo-1,3(4)-β-glucanase treatment enhances the fermentability of oat β-glucan and attenuates pro-inflammatory responses. Hence, this study shows that especially enzyme-treated oat β-glucans have a high potential for supplementation of infant formula.

    Community-based governance : Implications for ecosystem service supply in Berg en Dal, the Netherlands
    Bussel, Lenny G.J. Van; Haan, Nina De; Remme, Roy P. ; Lof, Marjolein E. ; Groot, Rudolf De - \ 2020
    Ecological Indicators 117 (2020). - ISSN 1470-160X
    Agricultural landscape - Co-management - Collaborative management - Land-use maps - Multi-level governance - Temporal dynamics

    Governance is an essential element in land-use decision-making and ecosystem management choices and thus for ecosystem service provisioning. Although a community-based approach, i.e. governance involving actors from all spheres of society (the state, market and civil society), is considered most appropriate for natural resource management, there is a lack of knowledge about its actual effects on environmental outcomes and ecosystem service supply in particular. To obtain insight in the effect of governance on ecosystem service provision in our study region (Berg en Dal, the Netherlands), we constructed ecosystem service maps for the period 1995 to 2012 using land-use maps. Also an inventory of the implemented governance models was created, based on interviews with stakeholders, supplemented with literature research. Our results show that 1) governance in Berg en Dal changed from top-down to more community-based models during the studied period; and 2) that the potential and actual supply of the majority of the investigated regulating, cultural and habitat ecosystem services increased during the studied period, at the expense of agricultural production. The interviewed local stakeholders also indicated that they have the perception that the landscape has improved during the last two decades. Although there is a clear connection between governance and improved ecosystem service supply, more research is needed to further develop causal relationships explaining the indirect effects and non-linear behavior within ecosystem service governance systems.

    Neochloris oleoabundans biorefinery : Integration of cell disruption and purification steps using aqueous biphasic systems-based in surface-active ionic liquids
    Suarez Ruiz, C.A. ; Martins, M. ; Coutinho, J.A.P. ; Wijffels, R.H. ; Eppink, M.H.M. ; Berg, C. van den; Ventura, S.P.M. - \ 2020
    Chemical Engineering Journal 399 (2020). - ISSN 1385-8947
    Aqueous biphasic systems - Microalgae disruption - Multi-product approach - Purification - Tensioactive compounds

    In this work, an approach to integrate the downstream processing of bioactive compounds present in the microalgae cells by combining the use of tensioactive compounds and aqueous biphasic systems (ABS) is proposed. For this purpose, several aqueous solutions using solvents with and without tensioactive nature were investigated on their capacity to disrupt the microalgae cells as well as to extract the different classes of biomolecules, namely pigments (chlorophylls a and b, and lutein), proteins and carbohydrates. Cationic tensioactive compounds were selected due to their high ability to simultaneously extract the different classes of compounds present in the Neochloris oleoabundans biomass. To fractionate pigments, proteins and carbohydrates extracted from the microalgae, ABS formed by polyethylene glycol (PEG 8000) and sodium polyacrylate (NaPA 8000) were used, with the solvent selected to disrupt the cells acting as electrolyte. This allowed to tune the biomolecule's partition reaching a selective fractionation. This approach provided the simultaneous extraction of different biomolecules (pigments, protein and carbohydrates) from the cells and, the subsequent origin of two fractions, one rich in proteins (extraction efficiencies of 100%) and carbohydrates (extraction efficiency of 80%) and the second concentrated in pigments (e.g. lutein, extraction efficiency of 98%). The further isolation of the biomolecules from the ABS forming solvents is proposed aiming at the development of an integrated downstream process, including the cell disruption/compounds extraction, the fractionation, and the isolation of the biomolecules.

    Is the farmer field school still relevant? Case studies from Malawi and Indonesia
    Berg, Henk van den; Ketelaar, Jan Willem ; Dicke, Marcel ; Fredrix, Marjon - \ 2020
    NJAS Wageningen Journal of Life Sciences 92 (2020). - ISSN 1573-5214
    Adult education - Farmer field school - Impact evaluation - Rural development - Sustainable rural livelihoods

    The capacity of farmers to adapt to changing environments is critical for sustainable, economically viable and resilient rural development. The Farmer Field School (FFS) was developed by FAO in the late 1980s to build farmers’ knowledge and skills for adaptive management. The FFS was subsequently implemented in over 90 countries by a multitude of stakeholders. We conducted case studies in Malawi and Indonesia to answer contemporary questions about the FFS, regarding its relevance at field level, its position in the institutional environment, and its contribution to rural development. We show that the FFS remains relevant at field level, helping farmers to adapt their agricultural practices and livelihood situation to changing circumstances. Differences in institutional arrangements between the two countries highlight the importance of a coordinated support for the FFS. Long-term impacts were found at farmer and institutional level. This study provides insight into the FFS, regarding the causal factors of change, institutional factors, and the role in continued development. As an approach that empowers rural people, the FFS thus contributes to achieving the Sustainable Development Goals.

    Soil nitrogen supply of peat grasslands estimated by degree days and soil organic matter content
    Pijlman, J. ; Holshof, G. ; Berg, W. van den; Ros, G.H. ; Erisman, J.W. ; Eekeren, N. van - \ 2020
    Nutrient Cycling in Agroecosystems 117 (2020). - ISSN 1385-1314 - p. 351 - 365.
    Fertilisation - Histosols - Mineralisation - Nitrogen efficiency - pH - Weather

    Accurate estimates of the quantity and rate of soil nitrogen supply (SNS) are essential to increase soil and farm N use efficiencies, in particular for soils high in organic matter. The objective of this work was to enhance the empirical understanding of the SNS of dairy grasslands on peat soils, using soil properties and weather variables. Data were collected from studies on herbage N uptake carried out between 1992 and 2017 in the western peat district of the Netherlands. For the period between March to mid October, SNS was estimated from the sum of mean growing season daily temperatures, soil organic matter (SOM) and applied calcium ammonium nitrate (CAN) N with a residual standard error of 25–27 kg ha−1. Each °C growing season temperature sum affected SNS by 78–90 g ha−1 and each g SOM per 100 g dry soil affected SNS by 3.6–3.9 kg ha−1, respectively. SNS was equally estimated for conditions with and without CAN fertilisation. Validation with data from independent field trials showed similar impacts of SOM and growing season temperature sum on SNS. The error of prediction of the presented models, however, was still too large for direct on-farm application and led to underestimations for a specific site. Nevertheless, the obtained models allow for an increased understanding of soil and farm N balances. The models can therefore be used for improved temporal and spatial SNS-adapted farming practice advice, which can potentially lead to reduced soil and farm N surpluses.

    Impacts of farmer field schools in the human, social, natural and financial domain : a qualitative review
    Berg, Henk van den; Phillips, Suzanne ; Dicke, Marcel ; Fredrix, Marjon - \ 2020
    Food Security (2020). - ISSN 1876-4517
    Adult education - Farmer field school - Impact assessment - Sustainable rural livelihoods

    The Farmer Field School (FFS) is a widely used method seeking to educate farmers to adapt agricultural decisions to diverse and variable field conditions. Out of 218 screened studies, 65 were selected to review the impact of the FFS. An analytical framework was developed with effects (outputs, outcomes and impacts) arranged according to the human, social, natural and financial domains. Impacts on non-participants of the FFS were addressed as peripheral effects. The FFS demonstrated its potential to enhance human, social, natural and financial capital of rural communities. Human capital was built in the form of critical thinking, innovation, confidence, and quality of life. Effects on social capital included mutual trust, bonding, collective action, networking, and emancipation. Natural capital was enhanced through improvements in field practices, food production, agricultural diversification, and food security. Financial capital was enhanced through increased income and profits, savings and loans schemes, with a potential to reduce poverty. The available body of evidence was unbalanced across the capital domains, providing high coverage of the natural domain but low coverage of the human, social and financial domains. In-depth case studies are needed to elucidate the interactions between livelihood assets, and the influences of the policy, institutional and external environment, in order to adjust FFS interventions aiming to optimize their impacts. Considering the positive effects the FFS can have on rural livelihoods, the FFS has potential to contribute to achieving the Sustainable Development Goals. However, quality assurance of the FFS and a balanced evaluation across the capital domains require attention.

    FoodTechAfrica. Monitoring 2018 - 2020 : End-term review report
    Rurangwa, E. ; Berg, Jolanda van den - \ 2020
    Wageningen Economic Research (Report / Wageningen Economic Research 2020-040C) - 20 p.
    Community factors affecting participation in larval source management for malaria control in Chikwawa District, Southern Malawi
    Gowelo, Steven ; McCann, Robert S. ; Koenraadt, Constantianus J.M. ; Takken, Willem ; Berg, Henk van den; Manda-Taylor, Lucinda - \ 2020
    Malaria Journal 19 (2020)1. - ISSN 1475-2875 - 1 p.
    Bacillus thuringiensis israelensis - Community - Larval source management - Malaria - Malawi

    BACKGROUND: To further reduce malaria, larval source management (LSM) is proposed as a complementary strategy to the existing strategies. LSM has potential to control insecticide resistant, outdoor biting and outdoor resting vectors. Concerns about costs and operational feasibility of implementation of LSM at large scale are among the reasons the strategy is not utilized in many African countries. Involving communities in LSM could increase intervention coverage, reduce costs of implementation and improve sustainability of operations. Community acceptance and participation in community-led LSM depends on a number of factors. These factors were explored under the Majete Malaria Project in Chikwawa district, southern Malawi. METHODS: Separate focus group discussions (FGDs) were conducted with members from the general community (n = 3); health animators (HAs) (n = 3); and LSM committee members (n = 3). In-depth interviews (IDIs) were conducted with community members. Framework analysis was employed to determine the factors contributing to community acceptance and participation in the locally-driven intervention. RESULTS: Nine FGDs and 24 IDIs were held, involving 87 members of the community. Widespread knowledge of malaria as a health problem, its mode of transmission, mosquito larval habitats and mosquito control was recorded. High awareness of an association between creation of larval habitats and malaria transmission was reported. Perception of LSM as a tool for malaria control was high. The use of a microbial larvicide as a form of LSM was perceived as both safe and effective. However, actual participation in LSM by the different interviewee groups varied. Labour-intensiveness and time requirements of the LSM activities, lack of financial incentives, and concern about health risks when wading in water bodies contributed to lower participation. CONCLUSION: Community involvement in LSM increased local awareness of malaria as a health problem, its risk factors and control strategies. However, community participation varied among the respondent groups, with labour and time demands of the activities, and lack of incentives, contributing to reduced participation. Innovative tools that can reduce the labour and time demands could improve community participation in the activities. Further studies are required to investigate the forms and modes of delivery of incentives in operational community-driven LSM interventions.

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