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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Effectiveness of zinc fortified drinking water on zinc intake, status and morbidity of rural Kenyan pre-school children
Kujinga-Chopera, P. - \ 2016
Wageningen University. Promotor(en): Michael Zimmermann, co-promotor(en): Inge Brouwer; D. Moretti. - Wageningen : Wageningen University - ISBN 9789462577572 - 127
preschool children - drinking water - zinc - fortification - kenya - diarrhoea - nutrient deficiencies - morbidity - childhood diseases - diet - diet studies - peuters en kleuters - drinkwater - zink - fortificatie - kenya - diarree - voedingsstoffentekorten - morbiditeit - kinderziekten - dieet - dieetstudies
Recirculatie bij Phalaenopsis technisch goed haalbaar : Investeringsdrempel voor hergebruik drainwater ligt hoog
Arkesteijn, Marleen ; Kromwijk, J.A.M. - \ 2016
Onder Glas 13 (2016)1. - p. 9 - 11.
tuinbouw - glastuinbouw - waterbeheer - potplanten - drainagewater - hergebruik van water - phalaenopsis - gewaskwaliteit - emissiereductie - normen - stikstof - mest - natrium - zink - ijzer - horticulture - greenhouse horticulture - water management - pot plants - drainage water - water reuse - phalaenopsis - crop quality - emission reduction - standards - nitrogen - manures - sodium - zinc - iron
Hergebruik van drainwater bij phalaenopsis heeft geen nadelige effecten voor de plantengroei. Dat is de eindconclusie uit het onderzoek dat het afgelopen jaar is uitgevoerd en dat de gewascoöperatie Potorchidee deels financierde. De gewascoöperatie is tevreden en wil het komende jaar een vervolgonderzoek naar het effect van gecontroleerd vrijkomende meststoffen. Hiermee kunnen ook niet recirculerende telers een stap zetten.
Gomphrena claussenii, a Zn and Cd hyperbioindicator species
Tomaz Villafort Carvalho, M. - \ 2016
Wageningen University. Promotor(en): Maarten Koornneef, co-promotor(en): Mark Aarts. - Wageningen : Wageningen University - ISBN 9789462576360 - 196
gomphrena - indicator plants - zinc - cadmium - indicator species - metal tolerance - gene expression - gomphrena - indicatorplanten - zink - cadmium - indicatorsoorten - metaaltolerantie - genexpressie
Gomphrena claussenii, a Zn and Cd hyperbioindicator species

A small group of plant species called metallophytes have evolved the ability to grow in highly metal-enriched soils that are toxic to other plants. Some of these metal-tolerant species have evolved the ability to accumulate high levels of metals or metalloids, such as nickel (Ni), zinc (Zn), arsenic (As), cadmium (Cd) and lead (Pb). Important progress towards understanding the physiological and molecular basis of metal and metalloid homeostasis in plants has been made by studying these metal hyperaccumulator species, which may also be useful for as the basis of phytoremediation technologies in which plants are used to stabilize or extract metals from soil. Gomphrena claussenii Moq. (Amaranthaceae), is a previously uncharacterized plant species which grows in the metal‑rich soils of a Zn mining area in the state of Minas Gerais, Brazil. This thesis describes the investigation of G. claussenii to determine the molecular basis of its ability to tolerate and accumulate Zn and Cd.

Chapter 2 presents a detailed comparative investigation of the physiological impact of Zn and Cd exposure on G. claussenii and the closely-related non-tolerant species G. elegans Mart. growing in soil or in hydroponic conditions. The impact of Zn/Cd in each species was determined by measuring growth characteristics such as biomass and root elongation. It was found that G. claussenii plants growing in the field in the Zn mining area accumulated up to 10434 µg Zn and 96 µg Cd per gram of shoot dry weight. Under hydroponic conditions, G. claussenii tolerated up to 3000 µM Zn and up to 100 µM Cd, showing only slight metal toxicity symptoms at the highest concentrations and no significant decrease in biomass or root length. In contrast, G. elegans showed significant toxicity symptoms at 100 µM Zn and 5 µM Cd. It was also found that both species accumulated more Zn and Cd in roots than shoots and that metal accumulation in G. claussenii showed a bioindicator-like response. Finally, the concentrations of other minerals such as Fe and Mn were not affected by Zn/Cd in G. claussenii shoots but declined dramatically in G. elegans in the presence of Zn/Cd. Taken together, these results indicated that G. claussenii is extremely tolerant to Zn and Cd and accumulates high levels of these metals in shoots, making it potentially valuable for phytoremediation applications.

Chapter 3 addresses the distribution of Zn/Cd in G. claussenii stem and leaf tissues, and metabolic profiles were used to investigate the involvement of metabolites in the sequestration of Zn/Cd. G. claussenii plants were exposed to high concentrations of Zn/Cd and analysed by scanning electron microscopy using energy dispersive X-ray (SEM-EDX) and micro-proton-induced X‑ray emission (micro-PIXE) technologies. We also investigated the dynamic profiles of primary metabolites in roots and shoots exposed to high levels of Zn/Cd to identify potential ligands for these metals. We observed the presence of abundant calcium oxalate (CaOx) crystals in the stem and leaf tissues of G. claussenii plants exposed to control and high levels of Cd, but intriguingly the number of crystals declined in the presence of Zn. Cd was shown to co‑localize with calcium (Ca) in the CaOx crystals, indicating that Cd sequestration in vacuolar CaOx crystals in G. claussenii is part of a tolerance mechanism to deal with excess Cd accumulation. Furthermore, citrate, malate and oxalate levels all increased in the shoots of G. claussenii exposed to Zn/Cd suggesting these organic acids are involved in metal chelation and contribute to metal tolerance.

Chapter 4 focuses on the molecular genetic aspects of hypertolerance in G. claussenii. The comparative transcriptomics analysis of G. claussenii and G. elegans was used to identify genes potentially responsible for the adaptation of G. claussenii to high Zn/Cd exposure. The transcriptional response of both species to high Zn/Cd concentrations was investigated by RNA-Seq analysis. Transcript sequences were annotated, and differential expression induced by Zn/Cd exposure was analysed in G. claussenii and G. elegans roots and shoots. Orthologous transcript pairs were identified between both species, allowing the direct comparison of gene expression profiles. G. elegans showed a stronger transcriptional response to metal exposure than G. claussenii, featuring the significant modulation of 10–20 times as many genes. Many of these transcripts encode proteins involved in metal homeostasis or stress responses. Metal hypertolerance in G. claussenii therefore appears to be a constitutive expression trait, based on adaptations in the metal homeostasis and general stress response.

Chapter 5 summarizes and evaluates the knowledge gained by the investigation set out in this thesis, focusing on the relevance of the information obtained from G. claussenii and its contribution to our current understanding of metal hypertolerance. It is also discussed the benefits of G. claussenii for phytoremediation applications, as well as its potential for future research activities.

Fonio (Digitaria exilis) in West Africa: towards improving nutrient quality
Koreissi, Y. - \ 2015
Wageningen University. Promotor(en): Michael Zimmermann, co-promotor(en): Inge Brouwer; Diego Moretti. - Wageningen : Wageningen University - ISBN 9789462574557 - 177
digitaria exilis - digitaria - voedingsstoffenverbetering - voedselkwaliteit - voedingswaarde - ijzer - zink - west-afrika - digitaria exilis - digitaria - nutrient improvement - food quality - nutritive value - iron - zinc - west africa

Fonio (Digitaria exilis) in West Africa: Towards improving nutrient quality


Hidden hunger affects a far greater percentage of the world’s population with iron and zinc deficiencies being the most common, particularly affecting women of reproductive age. The primary cause of the mineral and vitamin deficiencies in developing countries is inadequate intakes of multiple and bioavailable micronutrients in common cereal-based diets, emphasizing the need for increased quality of diets. Plant genetic diversity, and also indigenous foods and/ or traditional grains as fonio may play a critical role in reduction of the problem for resource poor populations. Fonio (Digitaria exilis) is the most ancient West African cereal representing a key crop in food supply during crop shortfall periods. However, less is known about its potential to contribute improving nutrition and health. In this context, the thesis investigated whether we could improve the nutrient quality of fonio, especially iron, to potentially contribute to the daily intake of population.

Investigations in this thesis comprised: i) the consumption pattern of fonio and its contribution to nutrient intakes (108 women aged 15‐49 year-old selected from 3‐stage cluster sampling procedure in Bamako, Mali for the purpose of the fonio project); ii) the validation of the Mali food composition database (TACAM) for assessing population level intakes of energy and nutrients (36 women out of 108 previously selected); iii) the genetic diversity, nutrient content especially bioavailable iron and zinc content and the effect of processing on fonio landraces (12 fonio landraces collected from farmers in Mali); iv) the sensory variability among fonio landraces (20 fonio landraces collected from farmers in Mali, Guinea and Burkina Faso); v) improved food processing combining dephytinisation with native phytase and fortification of fonio diet with iron to increase iron absorption (16 women aged 18-30 year-old from simple random sampling in Cotonou, Benin).

The results indicated that i) fonio is consumed one to three times/ month by 68% of our study population. The average daily portion size is 152g when consumed. Only 5% of the study population consumed fonio dishes contributing to 16% of the daily energy intake for the consumed portion size, reflecting the low consumption of fonio related to significant barriers such as availability of cooked fonio in urban markets, lack of consistent supply throughout the year, difficult post- harvest processing, high-quality product demand, hard texture coupled with time consuming cooking process, and high cost of fonio products.

The use of the adjusted TACAM is acceptable for estimating average intake at population level for macronutrients, calcium and zinc in a low intake population, but not for carbohydrate and iron intakes which was underestimated and vitamin A which was overestimated, nor for probability of adequate intakes and nutrient densities. At individual level, significant differences were observed between estimated and analyzed intakes for all the nutrients increasing with higher intakes.

The nutrient content of fonio landraces in Mali and the effect of processing of the nutrient values revealed i) a limited genetic variation of studied landraces, polymorphism level (3.5%) compared to 63% reported for 118 fonio accessions collected in West Africa, three different clusters only for Malians landraces compared to two clusters for Mali, Burkina Faso, Guinea and Benin together; ii) no statistically significant differences between fonio landraces for their iron and zinc content, iii) a high iron and phytate concentration in paddy fonio (35 and 514 mg/100 g dry weight) which reduces considerably with traditional processing, the most important losses occurring during processing from paddy to mid wet fonio (approximately 2 and 129 mg/100 g), 96% reduction for iron and 75% for phytate.

Fonio landraces in West Africa were different for their visual (colour and presence/absence of impurities) and their textural (consistency of cooked grain) charactersitics.

Exploring processing to increase iron biavailability from fonio meals confirm that whole wheat flour could be used as a source of natural phytase to produce low phytic acid containing fonio porridge. It showed also that dephytinisation using intrinsic wheat phytase reduced phytate-to-iron molar ratio from 23.7:1 to 2.7:1 after only 1 hour of incubation at 50ºC with pH of 5.0, and iron fortification decreased the molar ratio to 0.3:1. Dephytinisation with wheat phytase and fortification significantly increased iron absorption ratio from 2.6% to 8.2% in fonio porridges.

From these results, we can conclude that the current contribution of fonio to daily bioavailable iron intake is low due to small portion sizes being consumed in low frequency, to considerable losses during processing to mid-wet fonio, and to a high phytate-iron molar ratio. Fonio landraces from Mali, Guinea and Burkina Faso are variable in visual and textural characteristics (colour, presence of impurity and consistency of the cooked grain, respectively), determining the preference of consumers. Selecting landraces for preferred sensory properties may offer an entry point for processors who intend to promote the consumption of fonio and increase its role in diet. In absence of meaningful genetic diversity and variation in iron content in fonio landraces in Mali, there is little benefit in selecting landraces for natural high iron content. Dephytinisation using intrinsic wheat phytase could be a promising processing practice to improve iron bioavailability and fortification is required to increase the amount of absorbed iron from fonio meals.

Study of natural variation for Zn deficiency tolerance in Arabidopsis thaliana
Campos, A.C.A.L. - \ 2015
Wageningen University. Promotor(en): Maarten Koornneef, co-promotor(en): Mark Aarts. - Wageningen : Wageningen University - ISBN 9789462572515 - 232
arabidopsis thaliana - voedingsstoffentekorten - sporenelementtekorten - zink - genetische variatie - tolerantie - variatie - genetica - arabidopsis thaliana - nutrient deficiencies - trace element deficiencies - zinc - genetic variation - tolerance - variation - genetics

English summary

Zinc is an important structural component and co-factor of proteins in all living organisms. The model plant species for genetic and molecular studies, Arabidopsis thaliana, expresses more than 2,000 proteins with one or more Zn binding domains. Low Zn availability in arable soils is a widespread problem around the world which results in agricultural losses and the production of grains with low Zn content. The long-term consumption of low-Zn-content food items leads to severe health problems in humans as a result of severe or mild dietary Zn deficiency. Hence the importance of studying Zn homeostasis in plants and mechanisms involved in Zn deficiency tolerance aiming to enhance Zn concentration in plants edible parts and to develop varieties with a higher tolerance to Zn deficiency.

Plants are sessile organisms which trough evolution have developed specific traits in order to adapt to certain environmental conditions in their surroundings. As a result some plant genotypes are more tolerant to Zn deficiency and when exposed to low Zn conditions are able to perform better than others. To investigate the physiological mechanisms involved in Zn deficiency tolerance I examined natural variation present in a set of twenty diverse Arabidopsis thaliana accessions. In chapter 2, differences in shoot biomass production, Zn usage index (ZnUI), ionome (concentration of elements) and expression level of six key Zn deficiency responsive genes were studied. Accessions did not show large natural variation for shoot Zn concentration under Zn deficiency, while the decreases in shoot biomass and ZnUI were more variable. The conclusion from this is that accessions differ for the minimum Zn concentration required for growth which is associated with differences in Zn deficiency tolerance. We also found that the gene expression levels of three Zn transmembrane transporters (IRT3, ZIP3 and 4) in shoot were positively correlated with ZnUI and shoot biomass, but negatively correlated with shoot Zn concentration. This implies that a higher tolerance to Zn deficiency in A. thaliana is associated with an increased Zn translocation from root to shoot under low Zn. Furthermore, I used a logistic regression model to demonstrate that differences in the shoot ionome can be used as a biomarker to identify the plant Zn physiological state. Based on the changes in the concentrations of some elements in each of the Zn deficiency treatments it was possible to predict the Zn physiological state of the plants similarly to when Zn concentration is used alone.

The adaptive response to Zn deficiency involves physiological changes in shoots, but also in roots which play a key role in the acquisition of nutrients. In chapter 3 I used the same twenty A. thaliana accessions as described in chapter 2 to identify root system architecture traits and changes in the root ionome involved in a higher tolerance to Zn deficiency in plants. Similar to shoots, all accessions showed a strong reduction in root Zn concentration under Zn deficiency, whereas changes in other root system architecture traits were more variable between the accessions. These analyses showed that differences between the accessions in root system architecture traits and minimum Zn concentration required for growth are important for Zn deficiency tolerance. The Zn deficiency treatment also affects the formation of lateral roots and thus root system architecture. It was therefore not surprising that the Zn deficiency treatment induced changes in the concentrations of other elements which were correlated with changes in root traits.

Plants respond to different concentrations of Zn supply by changing the expression levels of genes involved in the Zn homeostasis network. This is important for the control of the Zn concentration and sequestration in plant cells, tissues and organs and involves the uptake, accumulation, transport and redistribution of Zn within the plant. Based on the work described in chapter 2, three A. thaliana accessions were selected with contrasting tolerance to Zn deficiency, and used for a whole genome transcription profiling analysis using RNA sequencing. Chapter 4 describes the identification of sets of general and core genes used by A. thaliana in its response to Zn deficiency. The purpose of using three accessions was to complement previous studies, which used only one accession, and identify new candidate genes involved in the general response to Zn deficiency in A. thaliana. General transcriptional changes were observed in the regulation of carbohydrate metabolism, glucosinolate biosynthesis and the circadian clock. As the transcriptional changes were recorded at two time points, it was also possible to distinguish early and late responses to Zn deficiency. The early response to Zn deficiency was stronger in roots with the induction of several Zn homeostasis genes and repression of Fe uptake genes. The late response to Zn deficiency comprised of the strong induction of several Zn uptake, transport and remobilization genes in both roots and shoots. These analysis confirmed several genes previously identified in Col-0 to have a general role in the Zn deficiency response, but it also led to the identification of new candidate genes, such as defensins and defensin-like genes, as very promising new actors in the A. thaliana Zn deficiency homeostasis network.

Chapter 5 describes the A. thaliana accession-specific Zn deficiency responsive transcript profiles, comparing Tsu-0, Pa-2 and Col-0, with the aim to identify biological processes involved in the observed differences in Zn deficiency tolerance between these three accessions. Tsu-0 displayed a high tolerance to Zn deficiency in shoot, Col-0 (reference accession) showed a high tolerance to Zn deficiency in both root and shoot, whereas Pa-2 root and shoot were more sensitive to Zn deficiency. Some of the accession-specific Zn deficiency responsive transcripts were involved in similar biological processes, such as defence response, programmed cell death and carbohydrates and glucosinolates metabolism. The differential regulation of these processes between the three accessions may reflect their differences in Zn deficiency tolerance. Among the Col-0 specific transcripts were several genes encoding proteins kinases which may play a role in a more specific separation of the abiotic and biotic stress responses in this accession and possibly involved in its higher tolerance to Zn deficiency in both shoots and roots. Tsu-0 specifically changes the expression of a set of shoot transcripts encoding ethylene responsive transcription factors which are involved in the regulation of shoot growth and plant tolerance to abiotic and biotic stresses, corresponding well with the observed shoot Zn deficiency tolerance. Accession Pa-2 down-regulated transcripts involved in cell wall organization in roots which correlates with its high sensitivity to Zn deficiency in this organ. Finally, the accessions specific response to Zn deficiency also resulted in the differential regulation of transcripts encoding transposases which may reflect large scale chromatin reorganization or demethylation in response to the stress condition.

The main findings of the research described in this thesis and their implications are described in the General Discussion (chapter 6). By investigating the response to Zn deficiency in a diverse set of A. thaliana accessions both at the physiological and transcriptional level important mechanisms involved in Zn deficiency tolerance were identified. Furthermore, several key candidate genes among the accessions general and accession-specific Zn deficiency responsive transcripts were identified. The further functional characterization of these genes is expected to reveal important new steps in the regulation of Zn homeostasis and Zn deficiency tolerance in A. thaliana.

Chemical and biological rhizosphere interactions in low zinc soils
Duffner, A. - \ 2014
Wageningen University. Promotor(en): Ellis Hoffland; Sjoerd van der Zee, co-promotor(en): Erwin Temminghoff. - Wageningen : Wageningen University - ISBN 9789462571631 - 131
bodem - zink - rizosfeer - voedingsstoffentekorten - bodemkunde - planten - voedingsstoffenopname (planten) - biologische beschikbaarheid - bodemkwaliteit - bodemvruchtbaarheid - soil - zinc - rhizosphere - nutrient deficiencies - soil science - plants - nutrient uptake - bioavailability - soil quality - soil fertility

Abstract of the PhD thesis entitled “Chemical and biological rhizosphere

interactions in low zinc soils” by Andreas Duffner

Soil provides ecosystem services critical for life. The availability of micronutrients, such as zinc (Zn), in soils is an essential factor for normal healthy growth and reproduction of plants. Zinc deficiency is, however, a global problem in crop production due to low Zn bioavailability in soils to plants. The bioavailable Zn fraction in soils is controlled by several factors and is not directly related to the total Zn content of soils. The main objective of this thesis was the determination of factors which control Zn bioavailability in soils to plants and to assess approaches to improve the prediction of Zn plant uptake.

Based on rhizobox experiments, in situ measurements in the rhizosphere as well as multisurface- and radial transport modeling approaches it was shown that the effect of root exuded citrate for increasing plant available Zn is soil specific and does not depend on a specific concentration of low molecular weight organic acids (e.g. citric acid) in the soil solution. Using various low Zn soils at the same time in an experimental setting improved the understanding of soil-responsiveness to root exuded citrate.

Another insight was that multisurface models, which are widely used to assess the potential ecotoxicological risk in metal-contaminated soils, are also accurate to predict the Zn activity in soils with low Zn levels. The predictions were validated with the soil column Donnan Membrane Technique by using various soils with low Zn levels. It was predicted that soil organic matter is the dominant Zn sorbent and controlled the Zn activity also at low soil organic matter levels. Examples were shown how this modeling approach can be used to assess management options to increase bioavailable Zn to plants.

Using soil extracted Zn fractions to directly predict the Zn plant uptake at low Zn levels was shown to be inaccurate. Using a stepwise approach where the steps of the uptake process were characterized with, respectively, Zn solid-solution distribution, adsorption of Zn to root surface, Zn uptake into root and Zn translocation to shoot made the prediction of Zn plant uptake more accurate. Root surface adsorbed Zn was shown to be a useful proxy for the bioavailable Zn.

The framework of experimental and modeling approaches which were developed and applied in this thesis can also be used to study the plant-availability of other micronutrients at low concentration levels and how that is affected by various root exuded ligands.

The bioavailability of four zinc oxide sources and zinc sulphate in broiler chickens
Veldkamp, T. ; Diepen, J.T.M. van; Bikker, P. - \ 2014
Wageningen : Wageningen UR Livestock Research (Report / Wageningen UR Livestock Research 806) - 27
vleeskuikens - biologische beschikbaarheid - zink - belgië - voedingsstoffenbehoeften - excretie - excreten - landbouw en milieu - pluimveevoeding - pluimveehouderij - wetenschappelijk onderzoek - broilers - bioavailability - zinc - belgium - nutrient requirements - excretion - excreta - agriculture and environment - poultry feeding - poultry farming - scientific research
Zinc is an essential trace element for all farm animal species. It is commonly included in animal diets as zinc oxide, zinc sulphate or organically bound zinc. Umicore Zinc Chemicals developed zinc oxide products with different mean particle sizes. Umicore Zinc Chemicals requested Wageningen UR Livestock Research to determine the bioavailability of four zinc oxide sources and zinc sulphate in broiler chickens. A precise estimate of the bioavailability of zinc sources is required both for fulfilling the zinc requirements of the animal and to reduce zinc excretion in excreta and the environment.
An evolutionary perspective on differential regulation of zinc and cadmium homeostatis genes in Arabidopsis thaliana and Noccaea caerulescens
Lin, Y.F. - \ 2014
Wageningen University. Promotor(en): Maarten Koornneef, co-promotor(en): Mark Aarts. - Wageningen : Wageningen University - ISBN 9789461738950 - 220
arabidopsis thaliana - zink - cadmium - homeostase - genen - evolutie - nucleotidenvolgordes - tolerantie - arabidopsis thaliana - zinc - cadmium - homeostasis - genes - evolution - nucleotide sequences - tolerance

Some plants can tolerate and accumulate unusually high levels of toxic metals, and the analysis of such plants can provide insights into the ecology of environments that are polluted with heavy metals due to human industrial activities. The study of heavy metal hyperaccumulators such as Noccaea caerulescens can show how plants cope with excess metals and increase their fitness when growing in metalliferous environments. In this thesis, I compared the molecular mechanisms of zinc (Zn) homeostasis and cadmium (Cd) response in the hyperaccumulator species N. caerulescens and its non-accumulator relative Arabidopsis thalianaby investigating the regulation of the ZNT1/ZIP4gene that promotes Zn uptake and Zn/Cd tolerance.I also studied the ecological advantages of metal hyperaccumulators in nature and determined the DNA sequences of the N. caerulescens transcriptometo find candidate genes that control metal hyperaccumulation and provide an evolutionary perspective on the emergence of this trait.

The functional characterization of the N. caerulescens and A. thaliana Zn-transporter genes NcZNT1 and AtZIP4 (and their promoters) showed how their differential expression pattern contributed to their role in metal tolerance and accumulation. The NcZNT1 gene is induced by Zn deficiency and the NcZNT1 protein is localized in the plasma membrane. Transgenic N. caerulescens roots containing a transgene for the green fluorescent protein (GFP) driven by the NcZNT1promoter revealed GFP fluorescence localized to pericycle and vascular tissues. This suggests that NcZNT1 contributes to metal loading into the xylem and long-distance metal transport. The overexpression of NcZNT1 in A. thaliana increased Zn and Cd tolerance and the capacity to accumulate these metals compared to wild-type plants. These results suggest that NcZNT1 plays an important role in Zn and Cd hypertolerance and hyperaccumulation in N. caerulescens, where it is expressed in both Zn-sufficient and Zn-excess conditions. The differential activity of the NcZNT1 and AtZIP4 promoters in N. caerulescens and A. thaliana implies that different cis-regulatory elements and trans-regulatory factors are present in both species.

The ecological advantage of hyperaccumulators in metal-contaminated soils was investigated by studying a natural nas1mutant, in which the Nicotianamine Synthase1 gene is disrupted by a transposon insertion. This mutant allele was found in three natural N. caerulescens populations, which were compared to wild-type plants in terms of phenotype and adaptive advantage. Although the transposon disrupted the gene, the loss of NAS1 gene activity was compensated by enhanced expression of NAS3 and NAS4, resulting in increased nicotianamine (NA) production, which enhanced the Zn and Cd accumulation in the nas1 mutants. This increased their metal sensitivity compared to wild-type plants, but also made them more toxic towards Pieris rapae caterpillars, which developed more slowly and gained less weight when fed on mutant plants exposed to excess Zn or Cd. Therefore, the possible selective advantage of the nas1 mutant in nature is high metal accumulation and the protection of plants from herbivores. Differences in nas1 allele frequency among the three natural populations suggests that nas1 alleles experience different degrees of natural selection or may be at different stages on the route to fixation.

Molecular evolutionary studies involve the identification of candidate genes that play a role in adaptation. Therefore, a comprehensive set of transcript sequences was obtained from N. caerulescens accession Ganges (GA) by 454 pyrosequencing. In total, the collected 23,836 isotigs (putative transcripts) were grouped into 20,378 isogroups and 93.2% of them could be matched to Brassicaceae protein sequences, which allowedtheir functional annotation. A total of 87 isogroups was annotated as metal homeostasis related genes, including metal transporter families, metal chelator biosynthesis families, and metal tolerance gene families, which are candidate genes for the molecular analysis of heavy metal homeostasis mechanisms. A group of genes required for the synthesis of glucosinolates, which are important secondary metabolites that protect plants against herbivores, were also shown to be expressed in N. caerulescens. The METALLOTHIONEIN3 (MT3) gene was found to have been duplicated in the N. caerulescens genome, when compared to related Brassicaceae. These transcript sequences will provide an important tool to annotate the genome sequence of the N. caerulescensGanges accession, which is in progress. This genome sequence will also be the basis of genome comparisons between the different N. caerulescens accessions that have different levels of metal accumulation and metal tolerance and which may therefore differ in terms of gene expression levels or modes of actions that affect metal homeostasis.

Recirculatie potorchidee 5. Zink
Blok, C. ; Kromwijk, J.A.M. - \ 2014
potplanten - orchidales - recirculatiesystemen - hergebruik van water - zink - aggregatie - reductie - effecten - pot plants - recirculating systems - water reuse - zinc - aggregation - reduction - effects
Als het zinkgehalte in het aanvoerwater hoger is dan de plantopname, loopt de concentratie in de wortelomgeving op. Recirculatie van drainwater leidt dan tot het langzaam maar gestadig oplopen van het zinkgehalte. Schadegrenzen voor potorchidee zijn niet bekend. Deze flyer geeft inzicht in effecten van zinkophoping bij andere gewassen en methoden om zinkophoping te verminderen.
Koper- en zinknormen voor varkens
Bikker, P. ; Jongbloed, A.W. - \ 2013
Lelystad : Wageningen UR Livestock Research (Rapport / Wageningen UR Livestock Research 746) - 31
varkens - zeugen - varkensvoeding - zeugenvoeding - koper - zink - voedingsbehoeften - richtlijnen (guidelines) - varkenshouderij - pigs - sows - pig feeding - sow feeding - copper - zinc - feed requirements - guidelines - pig farming
This report addresses copper and zinc requirements of growing pigs and reproductive sows and boars on the basis of scientific literature and provides a recommendation for copper and zinc standards in the diets.
Interpoleren kun je leren : een beslissingsondersteunend systeem voor interpolatie, aggregatie en desaggregatie in ruimte en tijd
Walvoort, D.J.J. ; Knotters, M. - \ 2013
Wageningen : Wettelijke Onderzoekstaken Natuur & Milieu (WOt-paper 26)
bodemchemie - kriging - zink - beslissingsondersteunende systemen - methodologie - kaarten - soil chemistry - zinc - decision support systems - methodology - maps
Tijd en geld ontbreken meestal om overal en altijd waarnemingen te verrichten. Daarom moeten in vrijwel elk onderzoek gegevens worden geïnterpoleerd naar niet-bezochte locaties of tijdstippen. Ook moeten gegevens vaak worden geaggregeerd tot bijvoorbeeld ruimtelijke of temporele totalen of gemiddelden, of worden gedesaggregeerd van grote naar kleine ruimtelijke of temporele eenheden. Dat kan op vele manieren, maar welke manier is het meest geschikt? Om onderzoekers te helpen bij het maken van een gefundeerde keuze hebben we een website met een beslissingsondersteunend systeem ontworpen, die we in deze paper onder de aandacht brengen ( Voorbeelden maken duidelijk dat de keuze van de juiste interpolatie-, aggregatieof desaggregatiemethode er wel degelijk toe doet.
Development of iron and zinc enriched mungbean (Vigna radiata L.) cultivars with agronomic traits in consideration
Singh, R. - \ 2013
Wageningen University. Promotor(en): Richard Visser, co-promotor(en): Sjaak van Heusden. - S.l. : s.n. - ISBN 9789461736840 - 175
vigna radiata - mungbonen (green gram) - mungbonen - sporenelementen - ijzer - zink - plantenveredeling - genetische diversiteit - voeding - india - voedselsoevereiniteit - vigna radiata - green gram - mung beans - trace elements - iron - zinc - plant breeding - genetic diversity - nutrition - india - food sovereignty

Malnutrition in India, particularly among women, children and adolescents is an emergency that needs immediate attention in this fast growing and developing country. Micronutrient deficiencies are threatening public health in India more and more. Deficiencies of micronutrients drastically affect growth, metabolism and reproductive phase in humans as it does in plants and animals. Cereal and pulse based Indian diets are qualitatively deficient in micronutrients such as iron, calcium, vitamin A and zinc. This is due to a low intake of income-elastic protective foods such as pulses, vegetables, fruits, and foods of animal origin. It is presumed that if we restore the geographical connection between food production and consumption in local food networks it will help in solving this nutritional problem in India. This offers new opportunities to tailor science & technology to location specific patterns of food production and consumption, which may lead to environmentally and socially sustainable agriculture. Despite global pressure (including from science and technology) to focus agricultural cultivation on a limited number of food crops, still many so-called orphan crops like mungbean do exist and are cultivated in location-specific crop rotation systems. Particularly, the seed legumes are of major nutritional importance, especially in developing countries, because they have high protein contents of good biological value. Out of the total sales of mungbean, about half of the sales are within the village which clearly establishes the need for development of infrastructure and facilities at the village level to serve the interests of the farm households. Moreover, it is also necessary to shift the focus of development from the urban market centres (largely developed) to the rural market centres. Linking breeding, nutrition, processing and standardisation of food products, may be designed within the experimental framework of empowering poor farmers. Hence, tailoring plant, food and social sciences to empower local mungbean production and consumption patterns has been designed as an interdisciplinary program of plant breeding, food technology, human nutrition and sociology of science and technology. Thus the ‘Tailoring Food Sciences to Endogenous Patterns of Local Food Supply for Future Nutrition’ (TELFUN) project aimed to help people in selecting their own way of local food production, processing and consumption of the best suited local food. The main objective is to strengthen “The Science in Society” approach by remodeling participatory research and development and the general aim of TELFUN was to attune disciplinary research objectives within an interdisciplinary framework to enhance food sovereignty and to improve mungbean based production and consumption pattern in selected research area (Haryana, India). As an example our research focused on further improving one of the potential nutritional crops, namely mungbean. The present work emphasizes on mungbean in general and especially on the available micronutrient variation in the mungbean germplasm. The mungbean (green gram), Vigna radiata (L.) Wilczek is native to the Indian subcontinent. They are warm season annuals, highly branched and having trifoliate leaves like the other legumes. Seeds of mungbean are small, ovoid in shape, and green in color. Mungbean seeds are high in protein (21%–28%), calcium, phosphorus and certain vitamins. Moreover they are easily digested and they replace scarce animal protein in human diets in vegetarian populations of the world. The selected area of research centres contain a high level of local biodiversity and are the locations for domestication of mungbean. This legume has co-evolved with their natural ecosystems and is well-adapted to withstand the local biotic and abiotic stresses. This will help in enabling the reconnection of the cultivation of the mungbean with their natural environments. Moreover, as domestication has taken place by local farmers during many centuries, they have accumulated local endogenous knowledge, which is very relevant for local food networks ( Thus to explore the potential mungbean network, the present thesis set its objectives. They were: i) identification of the major constraints, limitations and preferences of producer’s with regard to mungbean, ii) assessing the diversity in the available germplasm and assessing the effects of different environments on selected cultivars for their mineral micronutrients and iii) to make a start to develop tools for marker assisted breeding with regard to iron and zinc.

Adviesbasis voor de bemesting van akkerbouwgewassen : sporenelementen
Haan, J.J. de; Geel, W.C.A. van - \ 2013 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.
Verkenning mogelijke schaarste aan micronutriënten in het voedselsysteem
Chardon, W.J. ; Oenema, O. - \ 2013
Wageningen : Alterra, Wageningen-UR (Alterra-rapport 2413) - 43
bodemchemie - bemesting - mineralen - sporenelementen - kringlopen - borium - kobalt - koper - molybdeen - selenium - zink - schaarste - akkerbouw - tuinbouw - soil chemistry - fertilizer application - minerals - trace elements - cycling - boron - cobalt - copper - molybdenum - zinc - scarcity - arable farming - horticulture
Onder een micro-nutriënt wordt verstaan: een element dat essentieel is voor de groei en het functioneren van de plant, een dier of de mens, maar waarvan de benodigde hoeveelheid relatief klein is. In dit rapport zijn zes elementen geselecteerd omdat zij aantoonbaar essentieel zijn voor meerdere soorten gewassen of voor de veehouderij, en omdat de mate van vóórkomen in de aardkorst relatief gering is, waardoor (toekomstige) mondiale schaarste denkbaar is. Deze elementen zijn resp. borium, kobalt, koper, molybdeen, seleen en zink (B, Co, Cu, Mo, Se, en Zn). Alleen voor B en Se dragen de akker- en tuinbouw en de veehouderij significant bij aan het huidige mondiale gebruik: Se in de veehouderij 11% van totaal, en B in akker- en tuinbouw 12% van totaal verbruik. Prijsfluctuaties van Se en B zijn groot en wijzen op schaarste; binnen de industrie vindt recycling van deze elementen nauwelijks plaats. Binnen het voedselsysteem vindt recycling plaats van micronutriënten via hergebruik van dierlijke mest, gewasresten, compost en zuiveringsslib. Voor alle industrieel gebruikte micronutriënten zijn er alternatieven, behalve voor Co. In bodems vindt niet-duurzame ophoping plaats van Cu en Zn via mest, vooral in gebieden met een hoge veedichtheid.
Functional analysis of zinc hyperaccumulation related genes of Noccaea (Thlaspi) caerulescens for phytoremediation purposes
Hassan, Z. - \ 2013
Wageningen University. Promotor(en): Maarten Koornneef, co-promotor(en): Mark Aarts. - S.l. : s.n. - ISBN 9789461734303 - 223
thlaspi caerulescens - zink - hyperaccumulerende planten - fytoremediatie - genen - genexpressie - bodemverontreiniging - thlaspi caerulescens - zinc - hyperaccumulator plants - phytoremediation - genes - gene expression - soil pollution

Zinc (Zn) and cadmium (Cd) are toxic metals that can cause serious soil contamination when present in excess. Especially Cd exposure is a threat to human health. Plants can potentially be used to clean-up the Zn- and/or Cd-contaminated soils in a technology called “Phytoremediation”. Two major requirements for this technology are the availability of plants that are accumulating Zn/Cd to high levels in their leaves and that are producing high biomass. Noccaea caerulescens is a natural model Zn/Cd/Ni hyperaccumulator species that can accumulate up to 3% of Zn and 1% of Cd. Unfortunately it does not make a lot of biomass, and is thus unsuitable for phytoremediation. To overcome this limitation, higher biomass producing crops like tobacco can be genetically modified with genes from N. caerulescens to induce metal tolerance and hyperaccumulation. NcZNT1 and NcMTP1 are metal transporter genes in N. caerulescens. Zeshan Hassan has engineered tobacco to express both these genes, separately and in combination, to investigate their role in Zn, Cd accumulation and tolerance and to explore their potential in improving the phytoremediation capacity of plants. Transgenic tobacco lines were more tolerant to high Zn and Cd, leading to higher biomass compared to non-transformed controls, and they accumulated 2-4 fold higher Zn and 2-3.5 fold higher Cd when grown in artificial nutrient solution systems. More importantly they also did so when grown in soil collected from a metal-contaminated site. One of the conclusions of Zeshan Hassan’s PhD thesis is that both NcZNT1 and NcMTP1 genes are important for Zn and Cd tolerance and accumulation and that transgenic tobacco expressing these genes have enhanced phytoremediation capacity, which could lead to interesting future applications.

Zinc intake and dietary pattern in Jiangsu Province, China: consequences of nutrition transition
Qin, Y. - \ 2012
Wageningen University. Promotor(en): Frans Kok; Michael Zimmermann, co-promotor(en): Alida Melse-Boonstra; J.K. Zhao. - S.l. : s.n. - ISBN 9789461733740 - 133
zink - voedingstoestand - fortificatie - dieet - hypertensie - obesitas - china - zinc - nutritional state - fortification - diet - hypertension - obesity - china

Background: Jiangsu Province is an economically booming area in East China, where soil zinc concentrations are low. Nutrition transition to a dietary pattern with more animal source foods may have improved zinc intake in this area. However, such a transition may also have increased the burden of non-communicable diseases (NCDs), such as hypertension and obesity. Investigation of dietary patterns in relation to undernutrition and overnutrition could help to better address both problems.

Objectives: The first aim of this thesis was to assess zinc status in Jiangsu Province using dietary zinc intake, serum zinc and stunting as indicators, as well to investigate the potential of biofortified rice to improve zinc intake. The second aim was to investigate the association between dietary patterns and high blood pressure, taking obesity into account.

Methods:Data from the 2002 National Nutrition and Health Survey in Jiangsu Province were used to assess zinc intake in the population aged 4-89 years (n=3,867). Primary school children (n=2,268) were selected from three counties in the Province with relatively low soil zinc for assessment of stunting. Serum zinc was measured among children in the county where stunting was highest (n=297). Thirteen women were recruited in the same county for three test rounds with rice meals (zinc biofortified rice, zinc extruded fortified rice and control rice). Fractional zinc absorption (FAZ) was measured with the use of the double isotope tracer ratio method. Effect of biofortified rice with zinc, at a level of 2.7 and 3.8 mg/100g, on zinc intake was simulated in adults (n=2.819). For adults, four distinct dietary patterns were identified, named “traditional”, “Macho”, “sweet tooth” and “healthy” pattern. Associations were assessed between the four dietary patterns and blood pressure in adults (n=2,518) by using Poisson regression analysis.

Results:The overall prevalence of insufficient intake of zinc was 22.9%, with a higher prevalence in children (64.6%) and adolescents (64.9%), and in those with low socio-economic status (27.3%). Around 4% of the primary school children were stunted, and the prevalence of zinc deficiency measured by serum and hair zinc was 0.7%, and 15.2%, respectively. Biofortified 70Zn enriched rice with an intrinsic label was found to have higher fractional zinc absorption (FAZ) than extrinsically labeled fortified extruded rice. However, FAZ could not be accurately quantified because we could not determine the exact amount of isotope infused to subjects due to adhesion of zinc to the vial. When simulating zinc intake by replacing normal rice with zinc biofortified rice with either 2.7 and 3.8 mg/100g of zinc, the prevalence of insufficient zinc intake decreased from 15.4% to 6.5% and 4.4%, respectively. The “traditional” dietary pattern in Jiangsu Province was most strongly associated with high blood pressure (P for trend = 0.005). This pattern is characterized primarily by consumption of rice and fresh vegetable; secondary of pork and fish; and lastly of root vegetable and wheat flour, but also by high salt intake. Subjects with overweight and obesity were more likely to have high blood pressure than those with normal weight.

Conclusion: Children and adolescents had low dietary zinc intake, in Jiangsu Province, where the soil is also deficient in zinc. However, these findings did not match with the low prevalence of stunting and zinc deficiency based on serum zinc concentrations in primary school children from three rural areas of the Province. Zinc appears to be better absorbed from biofortified rice than from control rice or from extruded fortified rice, which needs further investigation. Simulated zinc intake from biofortified rice with zinc at a level of 2.7 mg/kg has the potential to significantly improve zinc intake, especially in the “traditional” dietary pattern. However, this pattern is also related to high blood pressure, which may be due to high salt intake. High blood pressure is also positively and independently related to obesity. Nutrition education is required to improve knowledge and awareness of healthy diets in Jiangsu Province.

Opsporing van te hoge koper- en zinkgehalten in varkensvoer via fecesonderzoek
Jongbloed, A.W. ; Jong, J. de; Vereijken, P.F.G. ; Voort, M. van der - \ 2012
Wageningen : RIKILT (Rapport / RIKILT 2011.018) - 57
varkenshouderij - varkensvoeding - voersamenstelling - koper - zink - fecessamenstelling - fecesonderzoek - kwantiteitscontrole - mengvoer - pig farming - pig feeding - feed formulation - copper - zinc - faeces composition - faecal examination - quantity controls - compound feeds
De nieuwe Voedsel en Waren Autoriteit (nVWA) van het Ministerie van Economische Zaken, Landbouw en Innovatie (EL&I) wil controleren of de voorgeschreven maximale hoeveelheden aan koper en zink in de voeding bij varkens niet worden overschreden. De vraag is hoe het beste gecontroleerd kan worden of de maximaal toegelaten concentaties aan Cu en Zn in de rantsoenen voor varkens zijn overschreden. In de stal kunnen namelijk naast de hoeveelheden Cu en Zn in het mengvoer ook nog spoorelementen via het drinkwater worden gegeven en ook kunnen deze spoorelementen vrijelijk over het mengvoer verstrekt worden. In dit verslag wordt beschreven of de gehaltes aan Cu en Zn in de feces van varkens een goede weergave kunnen geven van de hoeveelheden Zu en Zn, die via het voer en het drinkwater zijn toegediend en wat de nauwkeurigheid van deze schattingen is.
The preparation of biological reference materials for QUASIMEME
Kotterman, M.J.J. - \ 2011
IJmuiden : IMARES (Report / IMARES Wageningen UR C002/11) - 37
visserij - mossels - ecotoxicologie - koper - zink - fisheries - mussels - ecotoxicology - copper - zinc
Biological materials, consisting of three different batches of mussels; from Den Helder harbour (POPs, TBT), Irish mussels (metals) and Wadden Sea mussels, fortified with highly contaminated mussels from Belgium (POPs), and of one batch of turbot liver (metals) have been prepared for use in QUASIMEME interlaboratory studies for metal and organic contaminant analyses. The homogeneity of the prepared material was tested for metals or POPs, depending on the intended use of the material, and indicative concentrations for selected contaminants were reported.
Zinkvegetatie in Nederland en België
Janssen, J.A.M. ; Schaminee, J.H.J. - \ 2011
Excursieverslagen / Plantensociologische Kring Nederland 2011 (2011). - p. 5 - 14.
vegetatietypen - bodemchemie - zink - zuid-limburg - belgië - vegetation types - soil chemistry - zinc - belgium
Tijdens de PKN-excursie werden drie locaties bezocht: Cottessen, met het laatste restant zinkvegetatie binnen onze landsgrenzen, en Prayon en Theux in België.
Zinc and copper in dairy cattle feeding
Goselink, R.M.A. ; Jongbloed, A.W. - \ 2011
Lelystad : Wageningen UR Livestock Research (Report / Wageningen UR Livestock Research 519) - 18
melkveehouderij - melkkoeien - melkveevoeding - mineralen - zink - koper - dierlijke meststoffen - voersamenstelling - diergezondheid - vruchtbaarheid - dairy farming - dairy cows - dairy cattle nutrition - minerals - zinc - copper - animal manures - feed formulation - animal health - fertility
This literature study shows that dietary supplementation of copper and zinc to dairy cattle above current recommendations does not show convincing health benefits.
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