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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    "Hoe houden we de herontdekking van de natuur in leven?"
    Buijs, Arjen - \ 2020
    nature - experiential value - natural areas - Netherlands - leisure
    Association of Body Composition, Physical Functioning, and Protein Intake in Adult Patients With Mitochondrial Diseases
    Zweers, Heidi E.E. ; Bordier, Valentine ; ‘t Hulst, Jeanne in; Janssen, Mirian C.H. ; Wanten, Geert J.A. ; Leij-Halfwerk, Susanne - \ 2020
    Journal of Parenteral and Enteral Nutrition (2020). - ISSN 0148-6071
    BIA - body composition - DXA - handgrip strength - malnutrition - mitochondrial disease - nutrition assessment - physical functioning - sarcopenia

    Background: Whether decreased physical functioning of patients with mitochondrial disease (MD) is related to altered body composition or low protein intake needs clarification at the background of the nutrition state. Methods: In this 2-site cross-sectional study, MD patients were age-, body mass index (BMI)–, and gender-matched to controls. Body composition was assessed by dual-energy x-ray absorptiometry. Physical functioning was measured by handgrip strength, 6-minute walking test, 30-second sit-to-stand test (30SCT), and 6-minute mastication test. Total daily protein intake was calculated by 3-day food records. Malnutrition was assessed by Patient-Generated Subjective Global Assessment and the Global Leadership Initiative on Malnutrition (GLIM) criteria and sarcopenia by the 2018 consensus. Data were analyzed using independent samples t-tests, Fisher exact test, and Spearman and Pearson correlation coefficients. Results: Thirty-seven MD patients (42 ± 12 years, BMI: 23 ± 4 kg/m2, 59% females) and 37 matched controls were included. Handgrip strength was moderate, inversely related to fat mass index in both MD patients and controls, whereas it correlated with fat-free mass index in controls solely. Protein intake was associated with muscle strength (handgrip strength and 30SCT) in MD patients but not in controls. Twenty-seven MD patients (73%) were malnourished, and 5 (14%) were classified as sarcopenic. Conclusions: Muscle strength is related to body composition and protein intake in MD patients. This, in combination with the high incidence of both malnutrition and sarcopenia, warrants individual nutrition assessment in MD patients.

    Food system analysis of Arua district in Uganda : Working document KB project Improving food systems in less-favoured rural areas of East Africa
    Hengsdijk, Huib ; Roefs, Marlene ; Pereira da Silva, Fatima ; Hermelink, Marleen ; Lee, Jan van der; Deolu-Ajayi, Ayodeji ; Wösten, Henk ; Özkan Gülzari, Seyda ; Pittore, Katherine ; Beekman, Gonne ; Janssen, Valerie ; Alvarez Aranguiz, Adolfo ; Ndambi, Asaah ; Heesmans, Hanneke - \ 2020
    Wageningen : Wageningen University & Research - 50
    Modelling temperature effects in a membrane cascade system for oligosaccharides
    Rizki, Zulhaj ; Suryawirawan, Eric ; Janssen, Anja E.M. ; Padt, Albert van der; Boom, Remko M. - \ 2020
    Journal of Membrane Science 610 (2020). - ISSN 0376-7388
    Membrane cascades - Modelling - Nanofiltration - Oligosaccharide fractionation - Temperature effect

    Open nanofiltration of mixtures of fructo-oligosaccharides was assessed by experiment and by modelling the overall permeation behaviour of 3 different membranes. The temperature effect was modelled using the steric pore model, incorporating the molecular volumetric expansion of fructo-oligosaccharides as solutes, the decrease in the solution viscosity and the volumetric expansion of the membrane with increasing temperature. The thermal expansion of the solute was described as a linear increase in the bare molecular volume plus a non-linear decrease in its hydration number. The viscosity reduction was modelled by incorporating the temperature as a variable into an existing exponential relation derived by Chirife and Buera. The thermal expansion of membranes was described with a linear increase in the pore size and a linear decrease in its hydrodynamic resistance. Although the purity of the oligosaccharide product was hardly affected by the temperature, the yield was much lower at higher temperatures. The yield can therefore be improved by decreasing the temperature while maintaining the product purity. This behaviour was also observed in a 3-stage filtration cascade. The temperature effect is closely related to the increase in fluxes with temperature, leading to a different split of the feed into permeate and retentate. In a membrane cascade, the lower yield with higher temperatures was seen most strongly at the top stage, and much less at the middle and lower stages, which can be explained by the configuration of the cascade.

    Het Landelijk Waterkwaliteitsmodel : Uitbreiding van het Nationaal Water Model met waterkwaliteit ten behoeve van berekeningen voor nutriënten
    Bolt, F.J.E. van der; Kroon, T. ; Groenendijk, P. ; Renaud, L.V. ; Roovaart, J. van den; Janssen, C.M.C.M. ; Loos, S. ; Cleij, P. ; Linden, A. van den; Marsman, A. - \ 2020
    Wageningen : Wageningen Environmental Research (Wageningen Environmental Research rapport 3005) - 220
    De stuurgroep Nationaal Water Model heeft de opdracht gegeven een landelijk waterkwaliteitsmodel nutriënten te ontwikkelen. Dit Landelijk WaterKwaliteitsModel (LWKM) is gebaseerd op de recentste data, gebruikt de resultaten van het Landelijk hydrologisch Model en bouwt waar mogelijk voort op of maakt gebruik van onderdelen van eerdere modelinstrumenten als STONE en het Landelijk KRW-Verkenner Model (LKM). Dit rapport beschrijft de opzet, de realisatie, de gebruikte invoergegevens, de initialisatie, de kalibratie, de toetsing en resultaten van de eerste versie van het LWKM
    The importance of swelling for in vitro gastric digestion of whey protein gels
    Deng, Ruoxuan ; Mars, Monica ; Sman, Ruud G.M. Van Der; Smeets, Paul A.M. ; Janssen, Anja E.M. - \ 2020
    Food Chemistry 330 (2020). - ISSN 0308-8146
    Acid - Green fluorescent protein - In vitro gastric digestion - Pepsin - Swelling - Whey protein gel

    In this paper we report the importance of swelling on gastric digestion of protein gels, which is rarely recognized in literature. Whey protein gels with NaCl concentrations 0–0.1 M were used as model foods. The Young's modulus, swelling ratio, acid uptake and digestion rate of the gels were measured. Pepsin transport was observed by confocal laser scanning microscopy using green fluorescent protein (GFP). With the increase of NaCl in gels, Young's modulus increased, swelling was reduced and digestion was slower, with a reduction of acid transport and less GFP present both at surface and in the gels. This shows that swelling affects digestion rate by enhancing acid diffusion, but also by modulating the partitioning of pepsin at the food-gastric fluid interface and thereby the total amount of pepsin in the food particle. This perspective on swelling will provide new insight for designing food with specific digestion rate for targeted dietary demands.

    Improvement in municipal wastewater treatment alters lake nitrogen to phosphorus ratios in populated regions
    Tong, Yindong ; Wang, Mengzhu ; Peñuelas, Josep ; Liu, Xueyan ; Paerl, Hans W. ; Elser, James J. ; Sardans, Jordi ; Couture, Raoul Marie ; Larssen, Thorjørn ; Hu, Hongying ; Dong, Xin ; He, Wei ; Zhang, Wei ; Wang, Xuejun ; Zhang, Yang ; Liu, Yi ; Zeng, Siyu ; Kong, Xiangzhen ; Janssen, Annette B.G. ; Lin, Yan - \ 2020
    Proceedings of the National Academy of Sciences of the United States of America 117 (2020)21. - ISSN 0027-8424
    Anthropogenic source - Aquatic ecosystem - Nutrient balance - Wastewater treatment - Water quality change

    Large-scale and rapid improvement in wastewater treatment is common practice in developing countries, yet this influence on nutrient regimes in receiving waterbodies is rarely examined at broad spatial and temporal scales. Here, we present a study linking decadal nutrient monitoring data in lakes with the corresponding estimates of five major anthropogenic nutrient discharges in their surrounding watersheds over time. Within a continuous monitoring dataset covering the period 2008 to 2017, we find that due to different rates of change in TN and TP concentrations, 24 of 46 lakes, mostly located in China's populated regions, showed increasing TN/TP mass ratios; only 3 lakes showed a decrease. Quantitative relationships between in-lake nutrient concentrations (and their ratios) and anthropogenic nutrient discharges in the surrounding watersheds indicate that increase of lake TN/TP ratios is associated with the rapid improvement in municipal wastewater treatment. Due to the higher removal efficiency of TP compared with TN, TN/TP mass ratios in total municipal wastewater discharge have continued to increase from a median of 10.7 (95% confidence interval, 7.6 to 15.1) in 2008 to 17.7 (95% confidence interval, 13.2 to 27.2) in 2017. Improving municipal wastewater collection and treatment worldwide is an important target within the 17 sustainable development goals set by the United Nations. Given potential ecological impacts on biodiversity and ecosystem function of altered nutrient ratios in wastewater discharge, our results suggest that long-term strategies for domestic wastewater management should not merely focus on total reductions of nutrient discharges but also consider their stoichiometric balance.

    Higher Serum Vitamin D Concentrations Are Longitudinally Associated with Better Global Quality of Life and Less Fatigue in Colorectal Cancer Survivors up to 2 Years after Treatment
    Koole, Janna L. ; Bours, Martijn J.L. ; Roekel, Eline H. van; Breedveld-Peters, José J.L. ; Duijnhoven, Fränzel J.B. van; Ouweland, Jody van den; Breukink, Stéphanie O. ; Janssen-Heijnen, Maryska L.G. ; Keulen, Eric T.P. ; Weijenberg, Matty P. - \ 2020
    Cancer Epidemiology Biomarkers & Prevention 29 (2020)6. - ISSN 1055-9965 - p. 1135 - 1144.

    BACKGROUND: Vitamin D status may be an important determinant of health-related quality of life of colorectal cancer survivors. The current study investigated longitudinal associations between serum 25-hydroxyvitamin D3 (25OHD3) concentrations and quality of life in stage I-III colorectal cancer survivors up to 2 years after treatment. METHODS: Patients with colorectal cancer (n = 261) were included upon diagnosis. Home visits (including blood sampling) were performed at diagnosis and at 6 weeks, 6 months, 1 year, and 2 years after treatment. Serum 25OHD3 concentrations were measured using LC/MS-MS and adjusted for season. Validated questionnaires were used to assess global quality of life and cognitive functioning (EORTC-QLQ-C30), fatigue (EORTC-QLQ-C30 and Checklist Individual Strength, CIS), and depression and anxiety (Hospital Anxiety and Depression Scale). Statistical analyses were performed using linear mixed models and adjusted for sex, age, time since diagnosis, therapy, comorbidities, physical activity, and body mass index. RESULTS: At diagnosis, 45% of patients were vitamin D deficient (<50 nmol/L). After treatment, 25OHD3 concentrations increased on average with 3.1 nmol/L every 6 months. In confounder-adjusted models, 20 nmol/L increments in 25OHD3 were longitudinally associated with increased global quality of life [β 2.9; 95% confidence interval (CI), 1.5-4.3] and reduced fatigue (EORTC-QLQ-C30 subscale: β -3.5; 95% CI, -5.3 to -1.8 and CIS: β -2.8; 95% CI, -4.7 to -0.9). Observed associations were present both within and between individuals over time. CONCLUSIONS: Higher concentrations of 25OHD3 were longitudinally associated with better global quality of life and less fatigue in colorectal cancer survivors. IMPACT: This study suggests that higher 25OHD3 concentrations may be beneficial for colorectal cancer survivors. Future intervention studies are needed to corroborate these findings.

    Effect of methanethiol on process performance, selectivity and diversity of sulfur-oxidizing bacteria in a dual bioreactor gas biodesulfurization system
    Kiragosyan, Karine ; Picard, Magali ; Timmers, Peer H.A. ; Sorokin, Dimitry Y. ; Klok, Johannes B.M. ; Roman, Pawel ; Janssen, Albert J.H. - \ 2020
    Journal of Hazardous Materials 398 (2020). - ISSN 0304-3894
    Alkalilimnicola ehrlichii - Microbial dynamics - Thioalkalibacter halophilus - Thioalkalivibrio sulfidiphilus - Thiol toxicity

    This study provides important new insights on how to achieve high sulfur selectivities and stable gas biodesulfurization process operation in the presence of both methanethiol and H2S in the feed gas. On the basis of previous research, we hypothesized that a dual bioreactor lineup (with an added anaerobic bioreactor) would favor sulfur-oxidizing bacteria (SOB) that yield a higher sulfur selectivity. Therefore, the focus of the present study was to enrich thiol-resistant SOB that can withstand methanethiol, the most prevalent and toxic thiol in sulfur-containing industrial off gases. In addition, the effect of process conditions on the SOB population dynamics was investigated. The results confirmed that thiol-resistant SOB became dominant with a concomitant increase of the sulfur selectivity from 75 mol% to 90 mol% at a loading rate of 2 mM S methanethiol day−1. The abundant SOB in the inoculum – Thioalkalivibrio sulfidiphilus – was first outcompeted by Alkalilimnicola ehrlichii after which Thioalkalibacter halophilus eventually became the most abundant species. Furthermore, we found that the actual electron donor in our lab-scale biodesulfurization system was polysulfide, and not the primarily supplied sulfide.

    Doubling of Microalgae Productivity by Oxygen Balanced Mixotrophy
    Abiusi, Fabian ; Wijffels, Rene H. ; Janssen, Marcel - \ 2020
    ACS sustainable chemistry & engineering 8 (2020)15. - ISSN 2168-0485 - p. 6065 - 6074.
    Biomass yield on substrate - Carbon balance - Microalgae productivity - Mixotrophic cultivation - Oxygen balance

    Microalgae productivity was doubled by designing an innovative mixotrophic cultivation strategy that does not require gas-liquid transfer of oxygen or carbon dioxide. Chlorella sorokiniana SAG 211/8K was cultivated under continuous operation in a 2 L stirred-tank photobioreactor redesigned so that respiratory oxygen consumption was controlled by tuning the acetic acid supply. In this mixotrophic setup, the reactor was first operated with aeration and no net oxygen production was measured at a fixed acetic acid supply rate. Then, the aeration was stopped and the acetic acid supply rate was automatically regulated to maintain a constant dissolved oxygen level using process control software. Respiratory oxygen consumption was balanced by phototrophic oxygen production, and the reactor was operated without any gas-liquid exchange. The carbon dioxide required for photosynthesis was completely provided by the aerobic conversion of acetic acid. Under this condition, the biomass/substrate yield was 0.94 C-molx·C-molS -1. Under chemostat conditions, both reactor productivity and algal biomass concentration were doubled in comparison to a photoautotrophic reference culture. Mixotrophic cultivation did not affect the photosystem II maximum quantum yield (Fv/Fm) and the average-dry-weight-specific optical cross section of the microalgal cells. Only light absorption by chlorophylls over carotenoids decreased by 9% in the mixotrophic culture in comparison to the photoautotrophic reference. Our results demonstrate that photoautotrophic and chemoorganotrophic metabolism operate concurrently and that the overall yield is the sum of the two metabolic modes. At the expense of supplying an organic carbon source, photobioreactor productivity can be doubled while avoiding energy intensive aeration.

    Habitatrichtlijnrapportage 2019: Annex D Habitattypen : Achtergronddocument
    Janssen, John ; Bijlsma, Rienk-Jan ; Arts, Gertie ; Baptist, Martin ; Hennekens, Stephan ; Knegt, Bart de; Meij, Tom van der; Schaminée, Joop ; Strien, Arco van; Wijnhoven, Sander ; Ysebaert, Tom - \ 2020
    Wageningen : Wettelijke Onderzoekstaken Natuur & Milieu (WOt-technical report 171) - 97
    This document describes the concepts, data and methods used in the 2019 report (under Article 17 of the Habitats Directive) on the conservation status of habitat types for the parameters range, area, structure and functions, and future prospects. The ranges of nearly all habitat types have not changed. No reliable, updated data on area were available for most habitat types. The methodology for assessing structure and functions has been thoroughly revised to accommodate long-term monitoring data and meet the new reporting formats. The European Commission has also introduced a new method for assessing future prospects. The report presents the results and indicates where the methods and data can be improved.
    Alien flora across European coastal dunes
    Giulio, Silvia ; Acosta, Alicia Teresa Rosario ; Carboni, Marta ; Campos, Juan Antonio ; Chytrý, Milan ; Loidi, Javier ; Pergl, Jan ; Pyšek, Petr ; Isermann, Maike ; Janssen, John A.M. ; Rodwell, John S. ; Schaminée, Joop H.J. ; Marcenò, Corrado - \ 2020
    Applied Vegetation Science (2020). - ISSN 1402-2001
    alien flora - Atlantic - Baltic - Black Sea - coastal dune habitats - Mediterranean - neophyte - non-native - plant invasion - vegetation-plot data

    Questions: The spread of alien plant species is one of the main threats to the biodiversity of different natural habitats, and coastal dune habitats are among the most affected. There is a considerable local and regional variation in the level of alien plant invasion on coastal dunes. We asked what are the patterns of invasion across European coastal dunes and how they depend on habitat types and coastal regions. Location: Atlantic, Baltic, Black Sea and Mediterranean coasts of Europe. Methods: We used vegetation-plot records from shifting dunes and stable dune grasslands extracted from the European Vegetation Archive (EVA). We quantified richness, frequency and distribution of alien plant (neophyte) species across dune habitats and coastal regions. We also explored the donor habitats and invasion trajectories of these species. Results: In the flora of European coastal dunes, 7% of species were neophytes, for two-thirds originating from outside of Europe and mostly naturalised and ruderal. Shifting and stable dunes were similar in neophyte species composition, but there were more individual occurrences of neophytes in shifting dunes. The neophyte flora composition differed considerably between the Atlantic, Baltic, Black Sea and Mediterranean regions. The highest number of neophyte species was observed on the Atlantic dunes, while the highest number of neophyte occurrences was on the Black Sea dunes. Most of the neophytes originated from North America and the Mediterranean-Turanian region. Erigeron canadensis, Xanthium orientale, Oenothera biennis and Oenothera oakesiana were the most common neophytes. Conclusions: We provided a comprehensive assessment of alien plant invasions in the coastal dunes across Europe and highlighted that coastal dunes should be in the focus of European invasion management strategies.

    Vogel- en Habitatrichtlijnrapportage 2019
    Adams, Annemiek ; Bijlsma, Rienk-Jan ; Bos, Gerdien ; Clerkx, Sandra ; Janssen, John ; Kleunen, André van; Remmelts, Wilmar ; Rooijen, Nils van; Schaminée, Joop ; Schmidt, Anne ; Swaay, Chris van; Wijnhoven, Sander ; Woestenburg, Martin ; Aar, Mies van - \ 2020
    Wageningen : Wettelijke Onderzoekstaken Natuur & Milieu (Thema Informatievoorziening Natuur / Wettelijke Onderzoekstaken Natuur & Milieu ) - 52
    Maximization of sulfur formation in the presence of organic sulfur compounds in a dual bioreactor gas desulfurization system
    Kiragosyan, Karine - \ 2020
    Wageningen University. Promotor(en): A.J.H. Janssen, co-promotor(en): P. Roman; J.B.M. Klok. - Wageningen : Wageningen University - ISBN 9789463952583 - 180

    The growth of the global population and its associated increased demands for energy, food, and water has resulted in the intensification of industry and land use and hence loss of biodiversity and climate change. The overuse of natural resources, anthropogenic gas emissions and wastewater discharges into open waters cause environmental pollution, which, as a chain reaction, trigger  changes in the natural habitats of flora and fauna. Moreover, accumulation of CO2, N2O, CH4 and SO2 gases in the atmosphere cause health problems for millions of people and accelerate climate change.

    To sustain a global population of 7.7 billion people and manage their environmental footprint sustainably, the industry should transition towards a circular economy by using renewable resources and implementation of sustainable technologies. One such technology is the gas biodesulfurization process developed by our group in the Department of Environmental Technology at Wageningen University in cooperation with Delft University of Technology, University of Amsterdam, and industrial partners: Paqell B.V, Paques B.V and Shell. This technology emerged in the early 1990s when physicochemical desulfurization processes were dominating the market. Our biodesulfurization technology distinguishes itself because of its reduced operational and capital expenditures, and smaller environmental footprint. Since then, gas biodesulfurization has been intensively studied in order to facilitate higher sulfur recovery rates (>90 mol%) and stable process operations while treating a variety of gas feed streams. A high selectivity for sulfur is preferred because this will regenerate hydroxide ions, which are consumed when H2S is removed from gas streams. In addition, the consumption of air, energy, and caustic at sulfur-producing conditions are lower relative to the formation of sulfuric acid. Furthermore, the recovered sulfur slurry can be used as fertilizer and as fungicide. To maintain a stable sulfur selectivity, the biodesulfurization process operation should remain stable as well, especially when gas feed composition and sulfide concentration fluctuate. The composition of the feed gas depends on the industry that generates the sour gas. For example, biogas formed from the anaerobic digestion of wastewater in paper mill facilities has a relatively low amount of H2S (0.7 vol.%), whereas sour gas streams in the oil and gas industry are composed of up to 95 vol.% of H2S, a fraction of CO2, hydrocarbons, and thiols. The H2S concentration can vary greatly, not only between industries but also during the operation of a single installation. The daily H2S loading rate between Thiopaq installations may range from 10 kg day-1 up to 150 ton day-1. Therefore, the aim of this research was to achieve more sulfur formation and stable process operation in the presence of thiols.

    Cucurbits
    Messelink, Gerben J. ; Calvo, F.J. ; Marín, Francisco ; Janssen, Dirk - \ 2020
    In: Integrated Pest and Disease Management in Greenhouse Crops / Gullino, Maria Lodovica, Albajes, Ramon, Nicot, Philippe C., Springer International Publishing - ISBN 9783030223038 - p. 537 - 566.
    Several cucurbits species are cultivated in greenhouses worldwide. The most important genera are (1) Cucurbita, which includes squash, pumpkin, zucchini and gourds, (2) Citrullus, which includes watermelon and (3) Cucumis, which includes cucumber and various melons. Pests and diseases affecting cucurbit crops can vary considerably in relation to geographic area and cropping system. Growing in soil or on hydroponics strongly determines the presence of certain soil pathogens or nematodes. Also the way the crop is cultivated, the number of cropping cycles and the transition between cycles strongly affects the performance of pests, diseases and biological control agents. The main pests and diseases detrimental to cucurbits in various parts of the globe are reported here, along with the most effective or sustainable control strategies currently applied to manage them. Many pests can be controlled very successfully with natural enemies, but despite the recent developments on microbiological control agents, integrated pest management (IPM) with a low input of pesticides and, particularly fungicides, remains challenging in cucurbits, mainly because of viruses and diseases that are difficult to manage biologically or with selective control methods. Plant breeding programmes that develop disease tolerant cultivars that can be combined with arthropod natural enemies for pest control are promising to further develop robust IPM systems for cucurbits.
    Bioenergetics of peripheral blood mononuclear cells from endurance-trained and untrained healthy young adults analysed using extracellular flux assays
    Janssen, J.J.E. ; Lagerwaard, B. ; Nieuwenhuizen, A.G. ; Keijer, J. ; Boer, V.C.J. de - \ 2020
    In: Wias Annual Conference 2020 WIAS - p. 68 - 68.
    Skeletal muscle mitochondrial amount and function is positively affected by endurance exercise and training status1. However, to routinely assess mitochondrial function in response to exercise in humans, practical and non-invasive measurements of mitochondrial function are needed. We used near-infrared spectroscopy as a non-invasive method to assess the effect of training status on in vivo mitochondrial function2.In addition, we study peripheral blood mono nuclear cells (PBMCs), since PBMCs are relatively easily obtained from individuals and the immune system is involved in regulating the response of the body to exercise. Therefore we optimized and validated bright field imaging coupled to extracellular flux measurements in PBMCs to study the effect of training status on bioenergetic PBMC profiles. Methods. Extracellular flux measurements were performed using the Seahorse XFe Analyzer. For validation of our novel imaging approach in analyzing PBMC bio energetics, PBMCs were isolated from human buffy coats obtained from healthy blood donors and plated on coated Seahorse XFe96 cell culture microplates (0.5 – 3.0 x 105 cells/well). Brightfield images were taken using Cytation 1 and analyzed using ImagePro and ImageJ software. To study the effect of training status on bioenergetic PBMC profiles, eight endurance-trained (VO2max >57 ml/kg/min) and eight untrained(VO2max <47 ml/kg/min) young male adults were included. Results and conclusions Linear relationships were identified between plated cell number and pixel number (R2 = 0.9834,P < 0.001) and between calculated cell number (based on pixel number) and basal oxygen consumption rate (OCR) (R2 = 0.9491, P < 0.001) in multiple buffy coats, demonstrating reproducibility and suitability of our method for analyzing mitochondrial function in PBMCs over different days over a wide cell number range. Findings from our human trial on endurance-trained individuals indicated that PBMCs from endurance-trained individuals showed significantly lower coupling efficiency values (P = 0.0289) as well as higher proton leak compared to untrained individuals. No differences in basal respiratory OCR, maximal respiratory OCR or spare respiratory capacity in PBMCs from endurance-trained and untrained individuals were observed (P > 0.05). Our findings reveal a possible lower ATP production capacity of PBMCs from endurance-trained individuals and could contribute to further understanding how PBMC bioenergetics contribute to immune function and whole body performance.
    Fish Macrophages Show Distinct Metabolic Signatures Upon Polarization
    Wentzel, Annelieke S. ; Janssen, Joëlle J.E. ; Boer, Vincent C.J. de; Veen, Wouter G. van; Forlenza, Maria ; Wiegertjes, Geert F. - \ 2020
    Frontiers in Immunology 11 (2020). - ISSN 1664-3224 - 1 p.
    extracellular flux analysis - glycolysis - M1 M2 macrophage polarization - metabolic reprogramming - oxidative metabolism - oxidative phosphorylation (OXPHOS) - Seahorse - teleost

    Macrophages play important roles in conditions ranging from host immune defense to tissue regeneration and polarize their functional phenotype accordingly. Next to differences in the use of L-arginine and the production of different cytokines, inflammatory M1 macrophages and anti-inflammatory M2 macrophages are also metabolically distinct. In mammals, M1 macrophages show metabolic reprogramming toward glycolysis, while M2 macrophages rely on oxidative phosphorylation to generate energy. The presence of polarized functional immune phenotypes conserved from mammals to fish led us to hypothesize that a similar metabolic reprogramming in polarized macrophages exists in carp. We studied mitochondrial function of M1 and M2 carp macrophages under basal and stressed conditions to determine oxidative capacity by real-time measurements of oxygen consumption and glycolytic capacity by measuring lactate-based acidification. In M1 macrophages, we found increased nitric oxide production and irg1 expression in addition to altered oxidative phosphorylation and glycolysis. In M2 macrophages, we found increased arginase activity, and both oxidative phosphorylation and glycolysis were similar to control macrophages. These results indicate that M1 and M2 carp macrophages show distinct metabolic signatures and indicate that metabolic reprogramming may occur in carp M1 macrophages. This immunometabolic reprogramming likely supports the inflammatory phenotype of polarized macrophages in teleost fish such as carp, similar to what has been shown in mammals.

    Elevated viscosities in a simulated moving bed for γ-aminobutyric acid recovery
    Schultze-Jena, A. ; Boon, M.A. ; Vroon, R.C. ; Bussmann, P.J.Th. ; Janssen, A.E.M. ; Padt, A. van der - \ 2020
    Journal of Separation Science 43 (2020)7. - ISSN 1615-9306 - p. 1256 - 1264.
    chromatography - concentration profile - productivity - simulated moving bed - viscosity

    Process streams of agro-food industries are often large and viscous. In order to fractionate such a stream the viscosity can be reduced by either a high temperature or dilution, the former is not an option in case of temperature sensitive components. Such streams are diluted prior to chromatographic fractionation, resulting in even larger volumes and high energy costs for sub-sequential water removal. The influence of feed viscosity on the performance of simulated moving bed chromatography has been investigated in a case study of the recovery of a γ-aminobutyric acid rich fraction from tomato serum. This work addresses the chromatographic system design, evaluates results from a pilot scale operation, and uses these to calculate the productivity and water use at elevated feed concentration. At the two higher feed viscosities (2.5 and 4 mPa·s) water use is lower and productivity higher, compared to the lowest feed viscosity (1 mPa·s). The behavior of the sugars for different feed viscosities can be described well by the model using the ratio of feed to eluent as dilution factor. The behavior of γ-aminobutyric acid is highly concentration dependent and the recovery could not be accurately predicted.

    The economic value of R0 for selective breeding against microparasitic diseases
    Janssen, Kasper ; Bijma, Piter - \ 2020
    Genetics, Selection, Evolution 52 (2020)1. - ISSN 0999-193X - 1 p.

    BACKGROUND: Microparasitic diseases are caused by bacteria and viruses. Genetic improvement of resistance to microparasitic diseases in breeding programs is desirable and should aim at reducing the basic reproduction ratio [Formula: see text]. Recently, we developed a method to derive the economic value of [Formula: see text] for macroparasitic diseases. In epidemiological models for microparasitic diseases, an animal's disease status is treated as infected or not infected, resulting in a definition of [Formula: see text] that differs from that for macroparasitic diseases. Here, we extend the method for the derivation of the economic value of [Formula: see text] to microparasitic diseases. METHODS: When [Formula: see text], the economic value of [Formula: see text] is zero because the disease is very rare. When [Formula: see text]. is higher than 1, genetic improvement of [Formula: see text] can reduce expenditures on vaccination if vaccination induces herd immunity, or it can reduce production losses due to disease. When vaccination is used to achieve herd immunity, expenditures are proportional to the critical vaccination coverage, which decreases with [Formula: see text]. The effect of [Formula: see text] on losses is considered separately for epidemic and endemic disease. Losses for epidemic diseases are proportional to the probability and size of major epidemics. Losses for endemic diseases are proportional to the infected fraction of the population at the endemic equilibrium. RESULTS: When genetic improvement reduces expenditures on vaccination, expenditures decrease with [Formula: see text] at an increasing rate. When genetic improvement reduces losses in epidemic or endemic diseases, losses decrease with [Formula: see text] at an increasing rate. Hence, in all cases, the economic value of [Formula: see text] increases as [Formula: see text] decreases towards 1. DISCUSSION: [Formula: see text] and its economic value are more informative for potential benefits of genetic improvement than heritability estimates for survival after a disease challenge. In livestock, the potential for genetic improvement is small for epidemic microparasitic diseases, where disease control measures limit possibilities for phenotyping. This is not an issue in aquaculture, where controlled challenge tests are performed in dedicated facilities. If genetic evaluations include infectivity, genetic gain in [Formula: see text] can be accelerated but this would require different testing designs. CONCLUSIONS: When [Formula: see text], its economic value is zero. The economic value of [Formula: see text] is highest at low values of [Formula: see text] and approaches zero at high values of [Formula: see text].

    Geschiktheid zeewindparken voor maricultuur en passieve visserij : een kwantitatieve beoordeling van de kansrijkheid van de gebieden voor de potentiële productiviteit van een selectie aan commercieel interessante soorten
    Bogaart, Lisanne van den; Wal, Jan Tjalling van der; Tonk, Linda ; Bos, Oscar ; Coolen, Joop ; Poelman, Marnix ; Vergouwen, Sophie ; Duren, Luca van; Janssen, Henrice ; Timmermans, Klaas - \ 2020
    Yerseke : Wageningen Marine Research (Wageningen Marine Research report C127/19A) - 111
    In de Nederlandse Exclusieve Economische Zone (EEZ) zijn windparken gepland op diverse locaties. Door de windparken ontstaan nieuwe kansen voor multifunctioneel gebruik zoals maricultuur en niet-bodemberoerende visserij met passieve vistuigen. Deze studie brengt de potentiële - kwantitatieve - productiviteit van het kweken of vissen (passief vistuig) binnen bestaande, geplande en mogelijke toekomstige windparklocaties op de Noordzee in kaart voor een aantal vormen van medegebruik; kweek van bepaalde soorten zeewier en schelpdieren en de niet-bodemberoerende vangst van bepaalde soorten vissen, schaaldieren en inktvissen. Dit project is een vervolg op een voorgaand project waarbij een kwalitatieve beoordeling gegeven is van de kansrijkheid van de gebieden. In de huidige studie is voor een selectie van kansrijke soorten een berekening voor oogst of productie uitgevoerd. Daarnaast is dit rapport bedoeld om op basis van de huidige stand van kennis een inschatting te geven van de orde van grootte van het ruimtebeslag van zeewierproductie binnen toekomstige windparken. Met een aantal berekeningen wordt inzicht gegeven in de orde van grootte van opbrengsten, beschikbare/benodigde oppervlakten en benodigde nutriënten in de Noordzee. Op basis van deze analyse lijkt een areaal van enkele honderden km2 zeewierproductie realistisch, hierbij is uitgegaan van een grove indicatieve berekening, met diverse aannames. Op basis van de beschikbare voedingsstoffen voor mosselen zou tussen ca. 50 en 100 ton drooggewicht mosselen per km2 per jaar kunnen worden geproduceerd, waarbij de bronnen van onzekerheid in acht genomen dienen te worden. Om een indruk te krijgen van het (relatieve) voorkomen van vissen, weekdieren en schaaldieren is gebruik gemaakt van VMS- en logboekgegevens samen met gegevens van twee jaarlijkse surveys (BTS en IBTS). Het is echter niet mogelijk gebleken om voor alle geselecteerde soorten een kwantitatieve inschatting te maken, aangezien er nog weinig bekend is over ruimtelijke verdeling van deze soorten. Daarom is voor deze soorten een overzicht gegeven van wat er in de literatuur over bekend is.
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