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.

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    Bieten bijbemesten na opkomst
    Verstegen, Harry - \ 2015
    arable farming - sugarbeet - sugar content - fertilizer application - crop growth stage - boron fertilizers - boron - manganese - deficiency diseases - magnesium
    Influence of pH on the redox chemistry of metal (hydr)oxides and organic matter in paddy soils
    Pan, Y. ; Koopmans, G.F. ; Bonten, L.T.C. ; Song, J. ; Luo, Y. ; Temminghoff, E.J.M. ; Comans, R.N.J. - \ 2014
    Journal of Soils and Sediments 14 (2014)10. - ISSN 1439-0108 - p. 1713 - 1726.
    flooded soil - ion-binding - cadmium - iron - speciation - manganese - reduction - sorption - dynamics - mobilization
    The primary purpose of this study was to determine how flooding and draining cycles affect the redox chemistry of metal (hydr)oxides and organic matter in paddy soils and how the pH influences these processes. Our secondary purpose was to determine to what extent a geochemical thermodynamic equilibrium model can be used to predict the solubility of Mn and Fe during flooding and draining cycles in paddy soils. We performed a carefully designed column experiment with two paddy soils with similar soil properties but contrasting pH.We monitored the redox potential (Eh) continuously and took soil solution samples regularly at four depths along the soil profile during two successive flooding and drainage cycles. To determine dominant mineral phases of Mn and Fe under equilibrium conditions, stability diagrams of Mn and Fe were constructed as a function of Eh and pH. Geochemical equilibrium model calculations were performed to identify Mn and Fe solubility-controlling minerals and to compare predicted total dissolved concentrations with their measured values. Flooding led to strong Eh gradients in the columns of both soils. In the acidic soil, pH increased with decreasing Eh and vice versa, whereas pH in the alkaline soil was buffered by CaCO3. In the acidic soil, Mn and Fe solubility increased during flooding due to reductive dissolution of their (hydr)oxides and decreased during drainage because of re-oxidation. In the alkaline soil, Mn and Fe solubility did not increase during flooding due to Mn(II) and Fe(II) precipitation as MnCO3, FeCO3, and FeS. The predicted levels of soluble Mn and Fe in the acidic soil were much higher than their measured values, but predictions and measurements were rather similar in the alkaline soil. This difference is likely due to kinetically limited reductive dissolution of Mn and Fe (hydr)oxides in the acidic soil. During flooding, the solubility of dissolved organic matter increased in both soils, probably because of reductive dissolution of Fe (hydr)oxides and the observed increase in pH. Conclusions Under alternating flooding and draining conditions, the pH greatly affected Mn and Fe solubility via influencing either reductive dissolution or carbonate formation. Comparison between measurements and geochemical equilibrium model predictions revealed that reductive dissolution of Mn and Fe (hydr)oxides was kinetically limited in the acidic soil. Therefore, when applying such models to systems with changing redox conditions, such rate-limiting reactions should be parameterized and implemented to enable more accurate predictions of Mn and Fe solubility.
    Effects of sodium and sulfur on catalytic performance of supported iron catalysts for the Fischer-Tropsch synthesis of lower olefins
    Torres Galvis, H.M. ; Koeken, A.C.J. ; Bitter, J.H. ; Davidian, T. ; Ruitenbeek, M. ; Dugulan, A.I. ; Jong, K.P. de - \ 2013
    Journal of Catalysis 303 (2013). - ISSN 0021-9517 - p. 22 - 30.
    synthesis gas - selectivity - nanoparticles - potassium - promotion - manganese - size
    The Fischer–Tropsch synthesis of lower olefins (FTO) is an alternative process for the production of major chemical building blocks from natural gas, coal, or biomass-derived synthesis gas. The addition of low concentrations of sulfur plus sodium to Fe/a-Al2O3 resulted in catalysts with high C2–C4 olefins selectivity (~50%C), enhanced catalytic activity, and decreased methane production (
    Biovailability of copper and zinc in pig and cattle slurries
    Jakubus, M. ; Dach, J. ; Starmans, D.A.J. - \ 2013
    Fressenius Environmental Bulletin 22 (2013)4. - ISSN 1018-4619 - p. 995 - 1002.
    sequential extraction procedures - heavy-metals - soils - fractionation - speciation - sediments - manganese - sludge - nickel - lead
    Slurry is an important source of macronutrients, micro-nutrients and organic matter. Despite the considerable fertilizer value of slurry, it may be abundant in amounts of copper and zinc originating from dietary. The study presents quantitative changes in copper and zinc in individual slurries (pig and cattle slurries). The bioavailability of copper and zinc was estimated on the basis of amounts of the metals in isolated fractions using the sequential extraction method. Sequential techniques identify fractions which describe different connections of metals with the compost solid phase beginning with those that are easiest soluble up to those that dissolve with the greatest difficulties.Pig slurry was characterized by 2-fold higher amounts of copper and zinc in comparison to the levels detected in cattle slurries. Quantitative changes of the elements in the sequentially isolated fractions of analyzed slurries differed. First of all, this was dependent on the chemical character of a given metal, followed by the animal species, or the type of management. Irrespective of the type of slurry, 40-56% of the total amounts of copper were found in hardly available combinations, while available copper forms accounted for only 6.6–10.9%. Zinc was found predominantly in com-binations with iron and manganese oxides which, irrespective of the tested slurry, ranged from 130.64 mg·kg-1 to 293.60 mg·kg-1. Bioavailable metal contents, potentially introduced to soil with slurry doses, calculated as 170 kg total N/ha/year, ranged from 63.6 to 124.5 g for copper, and from 349.5 to 696.4 g for zinc. The estimated amounts of metal inputs to agricultural land demonstrate that soils are potentially at risk of heavy metal accumulation from the application of pig and cattle slurries.
    Adviesbasis voor de bemesting van akkerbouwgewassen : sporenelementen
    Haan, J.J. de; Geel, W.C.A. van - \ 2013
    Kennisakker.nl 2013 (2013)20 maart.
    akkerbouw - gewassen - mest - sporenelementen - borium - mangaan - koper - ijzer - zink - molybdeen - toepassing - dosering - bemesting - arable farming - crops - manures - trace elements - boron - manganese - copper - iron - zinc - molybdenum - application - dosage - fertilizer application
    In dit artikel worden adviezen gegeven voor de bemesting van akkerbouwgewassen met de sporenelementen; borium, mangaan, koper, ijzer, zink en molybdeen.
    One-step synthesis of sea urchin-like alpha-MnO2 using KIO4 as the oxidant and its oxidation of arsenite
    Wang, M.X. ; Tan, W.F. ; Feng, X.H. ; Koopal, L.K. ; Liu, M.M. ; Liu, F. - \ 2012
    Materials Letters 77 (2012). - ISSN 0167-577X - p. 60 - 62.
    formaldehyde oxidation - cryptomelane-type - facile synthesis - manganese - oxides - size
    Among several types of manganese oxides alpha-MnO2 is the most active due to its good catalytic, adsorption and ion exchange properties. Sea urchin-like alpha-MnO2 particles were synthesized by a one-step chemistry route at room temperature using MnSO4 in combination with KIO4 as oxidant. The obtained alpha-MnO2 was characterized using X-ray powder diffraction (XRD), structure refinement, electron microscopy and N-2 gas adsorption and used to investigate the property of the As (III) oxidation. Results revealed that the space group of the prepared product is I-4/m with lattice constants a = 9.840 angstrom and c = 2.856 angstrom, and the average grain diameter is around 6.7 nm. The BET surface area is 201 m(2).g(-1). Its maximum oxidation capacity of arsenite is up to 1086 mmol.kg(-1).
    Teff (Eragrostis tef) production constraints on Vertisols in Ethiopia: farmers' perceptions and evaluation of low soil zinc as yield-limiting factor.
    Haileselassie, B. ; Stomph, T.J. ; Hoffland, E. - \ 2011
    Soil Science and Plant Nutrition 57 (2011)4. - ISSN 0038-0768 - p. 587 - 596.
    iron - supplementation - manganese - infants - copper - trial
    Teff (Eragrostis tef (Zucc.) Trotter) is a major food crop in Ethiopia and Eritrea. It is well adapted to Vertisols. Yields are low (around 1000¿kg ha-1) despite fertilization with urea and diammonium phosphate. The objectives of this study were to understand farmers’ perception on teff production constraints and to evaluate on-farm yield response of teff to zinc (Zn) fertilization. We conducted a farm survey and a participatory fertilization experiment in three teff-based sites (peasant associations) on Vertisols in the mid highland and lowland agroecological zones in Ethiopia. Per site 10 farmers participated in the survey and on-farm experiment. Poor soil fertility in the mid highland and moisture deficit in the lowland agroecological zones were mentioned by farmers as major teff production constraints, respectively. On-farm application of Zn fertilizer at a rate of 8¿kg Zn ha-1 increased teff grain and straw yields by 14% and 15% on average, respectively, which could be economically profitable. Not all plots showed a positive response, however, indicating the necessity for enhanced insight in indicators for soil Zn bioavailability as a yield-limiting factor. Our study indicates the importance of Zn in teff production on Vertisols. We propose further research on management options to prepare for effective interventions based on the farm survey and on-farm experiment.
    Temporal dynamics in wheat grain zinc distribution: is sink limitation the key?
    Stomph, T.J. ; Choi, E.Y. ; Stangoulis, J.C.R. - \ 2011
    Annals of Botany 107 (2011)6. - ISSN 0305-7364 - p. 927 - 937.
    developing seeds - transport - biofortification - endosperm - phloem - barley - zn - remobilization - deposition - manganese
    Background and Aims - Enhancing the zinc (Zn) concentration in wheat (Triticum aestivum) grain is a breeding objective in order to improve human Zn nutrition. At enhanced plant Zn uptake, grain Zn levels do not increase proportionally and within the grain the endosperm Zn levels remain below grain Zn levels. This study analysed the temporal dynamics of Zn concentrations in grain tissues during grain filling to find major bottlenecks. Methods - Plants of two cultivars were grown at 1 and 5 mg Zn kg-1 soil. Individual panicles were harvested 7, 14, 24 or 34 d after their flowering or at maturity and seeds were dissected into constituting tissues, which were analysed for Zn and other minerals. Key Results - The Zn concentration of the crease was found to increase five- to nine-fold between 7 and 34 d after anthesis, while that of the endosperm decreased by 7 and 45 % when grown at 1 or 5 mg Zn kg-1, respectively. The Zn turnover rate (d-1) in the crease tissues was either independent of the Zn application level or higher at the lower Zn application level, and the Zn concentration increased in the crease tissues with time during grain filling while the turnover rate gradually decreased. Conclusions - There is significant within-seed control over Zn entering the seed endosperm. While the seed crease Zn concentration can be raised to very high levels by increasing external Zn supply, the endosperm Zn concentrations will not increase correspondingly. The limited transfer of Zn beyond the crease requires more research to provide further insight into the rate-determining processes and their location along the pathway from crease to the deeper endosperm
    Effect of 1-1 electrolyte concentration on the adsorption/desorption of copper ion on synthetic birnessite
    Wang, M. ; Wang, Y. ; Tan, W. ; Liu, F. ; Feng, X. ; Koopal, L.K. - \ 2010
    Journal of Soils and Sediments 10 (2010)5. - ISSN 1439-0108 - p. 879 - 885.
    heavy-metal ions - redox reactions - oxide minerals - adsorption - manganese - fe - desorption - hydroxides - surfaces - sorption
    Oxides are ubiquitous in nature and play an important role in scavenging metal ions from soils and sediments. At the common pH range of the natural environment the well-studied Fe and Al oxides mostly carry a positive charge and adsorbed amounts of heavy metals, and their desorption percentages decrease with increasing ionic strength. The less well studied but also important Mn oxides possess negative charges in the natural environment and this will lead to a different behavior. Therefore, it is useful to further investigate how the electrolyte concentration and type affect the metal ion adsorption/desorption by Mn oxides. The phyllomanganate birnessite was synthesized with hydrochloric acid and potassium permanganate, and characterized by X-ray diffraction and transmission electron microscopy. The point of zero charge and specific surface area (SSA) were determined by, respectively, the rapid potentiometric titration method and BET-N(2) method. The adsorption was measured after shaking the samples in contact with Cu(NO(3))(2) solution for 2 h and further equilibration for 22 h at pH 4.5 and 25 +/- 1A degrees C. The 1-1 electrolyte concentrations were adjusted to 0, 0.001, 0.01, 0.1, 0.5, and 1 mol L(-1) KNO(3) or KCl. The PZC and SSA of synthetic birnessite were 2.5 and 75 m(2) g(-1), respectively. The birnessite consisted of small needle-like particles. A maximum amount of Cu(2+) adsorbed on birnessite of 208 +/- 8 mmol kg(-1) and 2.77 +/- 0.11 A mu mol m(-2) by using the BET area is obtained. The adsorption amount decreased gradually with increasing ionic strength. This is primarily due to screening of the electrostatic attraction. For the same reason the percentage of desorption of Cu(2+) previously adsorbed on birnessite increased with increasing electrolyte concentration. Furthermore, the decrease of Cu(2+) adsorption with increasing ionic strength was higher in KCl solution than in KNO(3) solution. This difference is most likely related to Cu(2+)-Cl(-) complexation. The type and concentration of 1-1 electrolyte affect the Cu(2+) adsorption/desorption characteristics on Mn oxide. The amounts of Cu(2+) adsorbed on birnessite reduced, and the desorption percentage increased with increasing 1-1 electrolyte concentration. These results are opposite to that of metal ion binding to positive Fe and Al oxides. The principal differences can be explained on the basis of generic electrostatic effects.
    Adsorptive removal of manganese, arsenic and iron from groundwater
    Buamah, R. - \ 2009
    Wageningen University. Promotor(en): J.C. Schippers, co-promotor(en): B. Petrusevski. - [S.l.] : S.n. - ISBN 9789085855262 - 183
    grondwater - grondwaterverontreiniging - waterbeheer - watervoorziening - volksgezondheid - adsorptie - waterzuivering - mangaan - arsenicum - ijzer - ghana - grondwaterkwaliteit - groundwater - groundwater pollution - water management - water supply - public health - adsorption - water treatment - manganese - arsenic - iron - ghana - groundwater quality
    To determine the scale of the problem of arsenic, iron and manganese contamination of groundwater in Ghana a survey was performed in the first phase of the research to provide in depth information with respect to these contaminants. Presence of these mentioned contaminants in groundwater is not peculiar to Ghana alone. Many countries in the world have similar problems with their groundwater. Establishing the existence of the problem also calls for the need to find remedies. Over the years much studies have been done in the Unesco-ihe on the adsorptive mechanisms and techniques for iron and arsenic removal from groundwater. Therefore in this study much emphasis is placed on the adsorptive removal of manganese from groundwater. This research has the following as it objectives: 1. The conduction of a survey for the arsenic, iron and manganese content in selected groundwater aquifers in Ghana. 2. Determination of the arsenic, manganese and iron adsorption capacities of different locally available filter media. 3. Determination of the effect of pH on adsorption capacities of the selected media for arsenic, manganese and iron. To determine the effect of iron (II), manganese (II) presence on arsenic adsorption capacity of selected media – (competition). 4. Studies on the rate of oxidation of Fe (II) and Mn (II) adsorbed onto one or more selected media under different conditions (e.g. dissolved oxygen, pH etc.). 5. Determination of the rate of adsorption of Mn (II) onto one or more selected media under different oxic conditions. 6. To develop a conceptual model that describes the processes involved in adsorptive arsenic, manganese and iron removal. To investigate to what extent these processes can be described in a quantitative way with one or more mathematical models . Generally the study has the following relevance: 1. Provide a base line data on the arsenic and manganese content of selected groundwater aquifers in Ghana. 2. Provide information on the adsorption capacities of locally available filter media for manganese. 3. Contribute to the knowledge on the kinetics and mechanisms of catalytic adsorptive iron, manganese removal. 4. Provide an efficient backwashing procedure for regeneration of adsorptive sites in iron-oxide coated filters operating in the oxidative adsorption mode.
    Improvement of Lactobacillus Plantarum aerobic growth as directed by comprehensive transcriptome analysis
    Stevens, M.J.A. ; Wiersma, A. ; Vos, W.M. de; Kuipers, O.P. ; Smid, E.J. ; Molenaar, D. ; Kleerebezem, M. - \ 2008
    Applied and Environmental Microbiology 74 (2008)15. - ISSN 0099-2240 - p. 4776 - 4778.
    lactococcus-lactis - transport - manganese - wcfs1
    An aerobic Lactobacillus plantarum culture displayed growth stagnation during early growth. Transcriptome analysis revealed that resumption of growth after stagnation correlated with activation of CO(2)-producing pathways, suggesting that a limiting CO(2) concentration induced the stagnation. Analogously, increasing the CO(2) gas partial pressure during aerobic fermentation prevented the temporal growth stagnation
    Measurement of trace elements in liver biopsy samples from cattle
    Ouweltjes, W. ; Zeeuw, A.C. de; Moen, A. ; Counotte, G.H.M. - \ 2007
    Tijdschrift voor Diergeneeskunde 132 (2007)3. - ISSN 0040-7453 - p. 76 - 83.
    urine-analyse - diagnostische technieken - biopsie - diagnose - sporenelementen - rundvee - sporenelementtekorten - diervoeding - mineralenvoeding - lever - urine analysis - diagnostic techniques - biopsy - diagnosis - trace elements - cattle - trace element deficiencies - animal nutrition - mineral nutrition - liver - mineral status - beef-cattle - copper - zinc - supplementation - manganese - calves - iron
    Serum, plasma, or urine samples are usually used for the measurement of the trace elements copper, zinc, iron, selenium, because these samples are easy to obtain; however, these samples are not always appropriate. For example, it is not possible to measure molybdenum, the major antagonist of copper, in blood or urine. Therefore measurement of trace elements in liver tissue is considered the gold standard. For the assessment of selenium the method of choice remains determination of glutathion peroxidase in erythrocytes and for the assessment of magnesium determination of magnesium in urine. We determined the accuracy and repeatability of measuring trace elements in liver biopsies and whole liver homogenates. The levels of trace elements measured were similar in both preparations (92% agreement). Liver biopsy in live animals is a relatively simple procedure but not common in the Netherlands. Reference levels of trace elements, classified as too low, low, adequate, high, and too high, were established on the basis of our research and information in the literature. In a second study we investigated the practical aspects of obtaining liver tissue samples and their use. Samples were collected from cattle on a commercial dairy farm. Liver biopsy provided additional information to that obtained from serum and urine samples. We prepared a biopsy protocol and a test package, which we tested on 14 farms where an imbalance of trace minerals was suspected. Biopsy samples taken from 4 to 6 animals revealed extreme levels of trace elements
    The behaviour of EDDHA isomers in soils as influenced by soil properties.
    Schenkeveld, W.D.C. ; Reichwein, A.M. ; Temminghoff, E.J.M. ; Riemsdijk, W.H. van - \ 2007
    Plant and Soil 290 (2007)1-2. - ISSN 0032-079X - p. 85 - 102.
    calcareous soil - iron-chlorosis - chelating-agents - supply iron - acid eddha - plants - bicarbonate - fertilizers - iron(iii) - manganese
    FeEDDHA products are applied to correct iron chlorosis in plants and consist of a mixture of EDDHA isomers chelated to iron. In this study such mixtures have been divided into four (groups of) isomers: racemic o,o-EDDHA, meso o,o-EDDHA, o,p-EDDHA and rest-EDDHA. The physical and chemical properties of these isomers differ and hence does their ability to deliver Fe to plants. To come to a soil-specific iron fertilization recommendation, the behaviour of the EDDHA isomers in the soil needs to be understood. This behaviour has been examined in a soil interaction experiment as a function of time, and it has been related to soil properties. The isomer fractions remaining in solution can be ranked racemic o,o-FeEDDHA > meso o,o-FeEDDHA > rest-FeEDDHA > o,p-FeEDDHA, regardless of soil properties. The o,o-EDDHA isomers largely determine the Fe concentration in solution. Although rest-EDDHA also consists of compounds that chelate Fe more strongly than meso o,o-EDDHA, the latter is on average better capable of keeping Fe in solution upon interaction with soil. The principal adsorption surface differs per EDDHA isomer. For racemic o,o-FeEDDHA it is organic matter, for meso o,o-FeEDDHA it is iron (hydr)oxide and for o,p-FeEDDHA clay minerals. Cu and Al are important competing cations. Cu forms soluble complexes with o,p-EDDHA, and Al with meso o,o-EDDHA not chelated to Fe. Al is likely to affect the effectiveness of a potential shuttle effect. The tendency of o,p-FeEDDHA and rest-FeEDDHA to be removed from solution, makes these isomers less effective as iron fertilizer in soil application, in particular on clay soils.
    Uptake and distribution of root-applied or foliar-applied 65Zn after flowering in aerobic rice
    Jiang, W. ; Struik, P.C. ; Lingna, J. ; Keulen, H. van; Ming, Z. ; Stomph, T.J. - \ 2007
    Annals of Applied Biology 150 (2007)3. - ISSN 0003-4746 - p. 383 - 391.
    developing wheat grains - zinc uptake - zn - plants - accumulation - manganese - iron - cu - phytoremediation - nutrition
    We investigated the uptake and distribution of zinc (Zn) either applied to the roots or to the leaves in rice during grain development. Plants of two aerobic rice cultivars were grown in a nutrient solution with either sufficient Zn or surplus Zn. Root treatment with 1 week`s supply of both 65Zn and unlabelled Zn was started at flowering or 15 days after flowering (DAF). Foliar treatment with 65Zn applied to the flag leaf or to senescent leaves was carried out at flowering. When 65Zn was applied to roots, plants continued to take up Zn after flowering, even beyond 15 DAF, irrespective of cultivar and Zn nutritional status of the plants. During the 1 week of supply of both 65Zn and unlabelled Zn, which either started at flowering or 15 DAF, the absorbed 65Zn was mainly distributed to roots, stem and grains. Little 65Zn was allocated to the leaves. Following a week of 65Zn supply directly after flowering, under sufficient Zn or surplus Zn, the proportions of total 65Zn uptake allocated to the grains continued to change during grain filling (9¿33%). This Zn mainly came from the roots but under sufficient Zn supply also from the stem. With 65Zn applied to leaves (either the flag leaf or the lowest senescent leaf), both cultivars showed similar Zn distribution within the plants. About 45¿50% of the 65Zn absorbed was transported out of the 65Zn-treated leaf. From that Zn, more than 90% was translocated to other vegetative organs; little was partitioned to the panicle parts and even less to the grains. These results suggest that in rice plants grown under sufficient or surplus Zn supply, most of the Zn accumulated in the grains originates from uptake by roots after flowering and not from Zn remobilisation from leaves
    Day-to-Day Variations in Iron, Zinc and Copper in Breast Milk of Guatemalan Mothers
    Dhonukshe-Rutten, R.A.M. ; West, C.E. ; Schümann, K. ; Bulux-Hernandes, J. ; Solomons, N.W. - \ 2005
    Journal of Pediatric Gastroenterology and Nutrition 40 (2005)2. - ISSN 0277-2116 - p. 128 - 134.
    longitudinal changes - human lactation - trace-elements - vitamin-a - women - manganese - deficiency - supplementation - infancy - blood
    Objective: To assess the within-subject and between-subject coefficients of variation (CV) of iron, zinc and copper concentrations in the milk of Guatemalan mothers. Methods: We performed a cross-sectional study in lactating women who had delivered a healthy infant 1 to 6 months previously in two low-income peri-urban areas (San Bartolome Milpas Altas and Ciudad Peronia) and a low-income rural area (San Juan Chamelco) in Guatemala. Women infested with Ascaris lumbricoides or Trichuris trichiura received a single dose of albendazole (400 mg) or placebo. Two weeks after treatment, milk samples were collected on 3 or 4 consecutive days. Trace element concentrations in milk were measured by inductively coupled plasma/atomic emission spectrometry. Results: The instrumental error of the inductively coupled plasma/atomic emission spectrometry method, expressed as SD, was 0.04, 0.27 and 0.02 mg/L for iron, zinc and copper, respectively. Concentrations in milk samples collected from 47 mothers on 3 or 4 consecutive days, expressed as mean +/- SD, were 0.28 +/- 0.13, 2.03 +/- 0.37 and 0.29 +/- 0.07 mg/L for iron, zinc and copper, respectively. The within-subject CV was 46.1%, 18.2%, and 22.8% and the between-subject CV was 61.2%, 48.3% and 31.7% for iron, zinc and copper, respectively. Stage of lactation, infestation with intestinal parasites and residential area had a significant influence on milk zinc, copper and iron concentrations. Conclusions: One sample of milk is sufficient to give a reliable estimate of the zinc concentration in milk. Two samples taken on consecutive days are required for a reliable estimate of iron and copper concentrations
    Voorkoming en beheersing van gebreksverschijnselen in de bloembollenteelt : teelt en afbroeiproeven met als doel het voorkomen van ijzergebrek bij tulpen, hyacinten en narcissen van mangaangebrek bij tulpen en van vervroegde afsterving bij lelies
    Dam, A.M. van; Dam, M.F.N. van; Bruin, P.N.A. - \ 2004
    Lisse : PPO Bloembollen - 19
    gebreksziekten - tulipa - narcissus - hyacinthus - lilium - mangaan - ijzer - bemesting - bloembollen - gewasbescherming - deficiency diseases - tulipa - narcissus - hyacinthus - lilium - manganese - iron - fertilizer application - ornamental bulbs - plant protection
    Door veranderingen in de teelten en de aanscherping van het overheidsbeleid t.a.v. het gebruik van met name dierlijke mest kunnen zich bij de teelt van bloembollen verschijnselen voordoen die mogelijk samenhangen met een gebreksituatie. PPO heeft in dit project een aantal van deze verschijnselen onderzocht en geprobeerd er een oplossing voor te vinden. Met de dompeling van tulpenplantgoed in ijzerchelaat en andere preparaten ter voorkoming van ”koubont” werden in een oriënterende proef in 1998-1999 spectaculaire resultaten behaald. In het daaropvolgende driejarige onderzoek werd dit resultaat nooit in die mate geëvenaard. Slechts in het eerste jaar werd in een proef in Lisse met dompeling of veurbehandeling van het plantgoed met ijzerchelaat een beperkt positief gewas- en opbrengsteffect behaald; in het tweede jaar had, ook in Lisse, de toevoeging van WUXAL Mg aan het dompelbad een positief opbrengsteffect. Dit noopt tot de conclusie dat hier meer micro-elementen dan uitsluitend Fe een rol spelen en voorts dat seizoen, plantgoed en locatie in sterke mate bepalend zijn voor het al dan niet optreden van “koubont” en het effect van een bolbehandeling met ijzerchelaat of andere micro-elementen bevattende middelen. Door de overschakeling op niet-mangaanbevattende gewasbeschermingsmiddelen voor de vuurbestrijding in tulpen werd gevreesd dat de mangaanvoorziening van dit gewas in de knel zou komen. In onderzoek werd dat echter niet aangetoond. Het niet-mangaanbevattende middel fluazinam gaf dezelfde resultaten als het mangaanbevattende mancozeb. Alleen in Zwaagdijk had de combinatie van beide middelen soms een positief opbrengsteffect als gevolg van een betere gewasbeschermende werking. Na bespuitingen met chloorthalonil/prochloraz bleef de opbrengst wel achter. Met mangaanbespuitingen, ongeacht of dat via mancozeb was of via een toevoeging van Fertichel Mn aan het vuurbestrijdingsmiddel, kon in Zwaagdijk een in deze regio vaak voorkomende bladverkleuring worden beperkt. Net als in eerder onderzoek kon met magnesiumbespuitingen vroegtijdige bovengrondse afsterving van een leliegewas aanzienlijk worden beperkt, echter zonder dat het in dit geval ook leidde tot een positief opbrengsteffect of een hoger magnesiumgehalte in de geoogste bollen. De veronderstelling, opgeroepen door eerdere proeven, dat door magnesiumbespuiting de mangaanopname zou worden bevorderd werd niet bevestigd.
    Chemical conversion of alpha-Keto acids in relation to flavour formation in fermented foods
    Smit, B.A. ; Engels, W.J.M. ; Alewijn, M. ; Lommerse, G. ; Kippersluijs, E.A.H. ; Wouters, J.T.M. ; Smit, G. - \ 2004
    Journal of Agricultural and Food Chemistry 52 (2004)5. - ISSN 0021-8561 - p. 1263 - 1268.
    cheese flavor - cheddar cheese - key odorants - amino-acids - bacteria - catabolism - oxidation - lactococci - indicator - manganese
    Formation of flavor compounds from branched-chain -keto acids in fermented foods such as cheese is believed to be mainly an enzymatic process, while the conversion of phenyl pyruvic acid, which is derived from phenylalanine, also proceeds chemically. In this research, the chemical conversion of -keto acids to aldehydes with strong flavor characteristics was studied, with the main focus on the conversion of -ketoisocaproic acid to the aldehyde 2-methylpropanal, and a manganese-catalyzed reaction mechanism is proposed for this conversion. The mechanism involves keto-enol tautomerism, enabling molecular oxygen to react with the -carbon atom of the -keto acid, resulting in a peroxide. This peroxide can react in several ways, leading to unstable dioxylactone or noncyclic intermediates. These intermediates will break down into an aldehyde and oxalate or carbon oxides (CO and CO2). All the -keto acids tested were converted at pH 5.5 and in the presence of manganese, although their conversion rates were rather diverse. This chemical reaction might provide new ways for controlling cheese flavor formation with the aim of acceleration of the ripening process or diversification of the flavor characteristics
    Complete genome sequence of Lactobacillus plantarum WCFS1
    Kleerebezem, M. ; Boekhorst, J. te; Kranenburg, R. van; Molenaar, D. ; Kuipers, O.P. ; Leer, R. ; Tarchini, R. ; Peters, S.A. ; Sandbrink, H.M. ; Fiers, M.W.E.J. ; Stiekema, W.J. ; Klein Lankhorst, R.M. ; Bron, P.A. ; Hoffer, S.M. ; Nierop Groot, M.N. ; Kerkhoven, R. ; Vries, M.C. de; Ursing, B. ; Vos, W.M. de; Siezen, R.J. - \ 2003
    Proceedings of the National Academy of Sciences of the United States of America 100 (2003)4. - ISSN 0027-8424 - p. 1990 - 1995.
    lactic-acid bacteria - resistant staphylococcus-aureus - bacillus-subtilis - genes - cloning - chromosome - expression - metabolism - manganese - knockout
    The 3,308,274-bp sequence of the chromosome of Lactobacillus plantarum strain WCFS1, a single colony isolate of strain NCIMB8826 that was originally isolated from human saliva, has been determined, and contains 3,052 predicted protein-encoding genes. Putative biological functions could be assigned to 2,120 (70%) of the predicted proteins. Consistent with the classification of L. plantarum as a facultative heterofermentative lactic acid bacterium, the genome encodes all enzymes required for the glycolysis and phosphoketolase pathways, all of which appear to belong to the class of potentially highly expressed genes in this organism, as was evident from the codon-adaptation index of individual genes. Moreover, L. plantarum encodes a large pyruvate-dissipating potential, leading to various end-products of fermentation. L. plantarum is a species that is encountered in many different environmental niches, and this flexible and adaptive behavior is reflected by the relatively large number of regulatory and transport functions, including 25 complete PTS sugar transport systems. Moreover, the chromosome encodes >200 extracellular proteins, many of which are predicted to be bound to the cell envelope. A large proportion of the genes encoding sugar transport and utilization, as well as genes encoding extracellular functions, appear to be clustered in a 600-kb region near the origin of replication. Many of these genes display deviation of nucleotide composition, consistent with a foreign origin. These findings suggest that these genes, which provide an important part of the interaction of L. plantarum with its environment, form a lifestyle adaptation region in the chromosome.
    Anaerobic oxidation of 2-chloroethanol under denitrifying conditions by Pseudomonas stutzeri
    Dijk, J.A. ; Stams, A.J.M. ; Schraa, G. ; Ballerstedt, H. ; Bont, J.A.M. de; Gerritse, J. - \ 2003
    Applied Microbiology and Biotechnology 63 (2003). - ISSN 0175-7598 - p. 68 - 74.
    ribosomal-rna gene - degradation - denitrification - 1,2-dichloroethane - reduction - community - manganese - sequence - iron - soil
    A bacterium that uses 2-chloroethanol as sole energy and carbon source coupled to denitrification was isolated from 1,2-dichloroethane-contaminated soil. Its 16 S rDNA sequence showed 98% similarity with the type strain of Pseudomonas stutzeri (DSM 5190) and the isolate was tentatively identified as Pseudomonas stutzeri strain JJ. Strain JJ oxidized 2-chloroethanol completely to CO2 with NO3- or O-2 as electron acceptor, with a preference for O-2 if supplied in combination. Optimum growth on 2-chloroethanol with nitrate occurred at 30 degreesC with a mu(max) of 0.14 h(-1) and a yield of 4.4 g protein per mol 2-chloroethanol metabolized. Under aerobic conditions, the mu(max) was 0.31 h(-1). NO2- also served as electron acceptor, but reduction of Fe(OH)(3), MnO2, SO42-, fumarate or ClO3- was not observed. Another chlorinated compound used as sole energy and carbon source under aerobic and denitrifying conditions was chloroacetate. Various different bacterial strains, including some closely related Pseudomonas stutzeri strains, were tested for their ability to grow on 2-chloroethanol as sole energy and carbon source under aerobic and denitrifying conditions, respectively. Only three strains, Pseudomonas stutzeri strain LMD 76.42, Pseudomonas putida US2 and Xanthobacter autotrophicus GJ10, grew aerobically on 2-chloroethanol. This is the first report of oxidation of 2-chloroethanol under denitrifying conditions by a pure bacterial culture.
    Production of the flavor compound benzaldehyde by lactic acid bacteria: role of manganese and its transport systems in Lactobacillus plantarum
    Nierop Groot, M.N. - \ 2001
    Wageningen University. Promotor(en): W.M. de Vos; M. Kleerebezem. - S.l. : S.n. - ISBN 9789058085399 - 139
    melkzuurbacteriën - lactobacillus plantarum - benzaldehyde - productie - mangaan - ionentransport - lactic acid bacteria - lactobacillus plantarum - benzaldehyde - production - manganese - ion transport
    One of the aims of the research described in this thesis (Chapter 1 and 2) was to investigate the conversion of phenylalanine to the aromatic flavor compound benzaldehyde in lactic acid bacteria (LAB) (Chapter 3). Lactobacillus plantarum was used as the model organism to study phenylalanine degradation in LAB. This bacterium was selected in an initial screening for phenylalanine degradation since it produced higher levels of benzaldehyde than other LAB (Chapter 4). In addition, the availability of genetic tools for this bacterium was an advantage for the second aim of this thesis: the identification and characterization of Mn 2+transport systems in L. plantarum (described in Chapter 5 and 6).

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