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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    Assessing the combined toxicity effects of three neonicotinoid pesticide mixtures on human neuroblastoma SK-N-SH and lepidopteran Sf-9 cells
    Cheng, Lin ; Lu, Yangyang ; Zhao, Zhihui ; Hoogenboom, Ron L.A.P. ; Zhang, Qicai ; Liu, Xing ; Song, Wei ; Guan, Shuhui ; Song, Weiguo ; Rao, Qinxiong - \ 2020
    Food and Chemical Toxicology 145 (2020). - ISSN 0278-6915
    Combined toxicity - Human neuroblastoma cell line SK-N-SH - Lepidopteran (Spodoptera frugiperda) cell line Sf-9 - Mixtures - Neonicotinoid pesticides

    Neonicotinoid insecticides have been widely used in plant protection against pests worldwide. Generally, more than one neonicotinoids are detected in plants and foods, and such mixtures may show combined toxicity and increase the risk for both insects and higher organisms. In this study, the combined toxicity of imidacloprid (IM), acetamiprid (AC) and thiamethoxam (TH) was investigated using human neuroblastoma cell line (SK-N-SH) and lepidopteran cell line (Sf-9). Results showed that binary and ternary mixtures could enhance the inhibition of growth of both SK-N-SH and Sf-9 cells at low doses. In SK-N-SH cells, based on CompuSyn software analysis, all the mixtures of IM+AC, IM+TH, AC+TH and IM+AC+TH showed synergistic effects at concentrations < 50 mg/L, but IM+AC, IM+TH showed antagonistic effects at higher concentrations. For Sf-9 cells, all mixtures revealed synergistic effects at low concentrations (< 0.1 mg/L) except IM+AC, showing antagonism at higher concentrations (> 0.5 mg/L). The toxicity thresholds of mixtures denoted by BMDL10 values were all lower than those for single pesticides and the combined BMDL10 value of AC+TH was the lowest one. It is concluded that the co-occurrence of several neonicotinoid insecticides may enhance their toxicity and aggravate the health risk for both insects and human.

    Towards a multiscale crop modelling framework for climate change adaptation assessment
    Peng, Bin ; Guan, Kaiyu ; Tang, Jinyun ; Ainsworth, Elizabeth A. ; Asseng, Senthold ; Bernacchi, Carl J. ; Cooper, Mark ; Delucia, Evan H. ; Elliott, Joshua W. ; Ewert, Frank ; Grant, Robert F. ; Gustafson, David I. ; Hammer, Graeme L. ; Jin, Zhenong ; Jones, James W. ; Kimm, Hyungsuk ; Lawrence, David M. ; Li, Yan ; Lombardozzi, Danica L. ; Marshall-Colon, Amy ; Messina, Carlos D. ; Ort, Donald R. ; Schnable, James C. ; Vallejos, C.E. ; Wu, Alex ; Yin, Xinyou ; Zhou, Wang - \ 2020
    Nature Plants 6 (2020)4. - ISSN 2055-026X - p. 338 - 348.

    Predicting the consequences of manipulating genotype (G) and agronomic management (M) on agricultural ecosystem performances under future environmental (E) conditions remains a challenge. Crop modelling has the potential to enable society to assess the efficacy of G × M technologies to mitigate and adapt crop production systems to climate change. Despite recent achievements, dedicated research to develop and improve modelling capabilities from gene to global scales is needed to provide guidance on designing G × M adaptation strategies with full consideration of their impacts on both crop productivity and ecosystem sustainability under varying climatic conditions. Opportunities to advance the multiscale crop modelling framework include representing crop genetic traits, interfacing crop models with large-scale models, improving the representation of physiological responses to climate change and management practices, closing data gaps and harnessing multisource data to improve model predictability and enable identification of emergent relationships. A fundamental challenge in multiscale prediction is the balance between process details required to assess the intervention and predictability of the system at the scales feasible to measure the impact. An advanced multiscale crop modelling framework will enable a gene-to-farm design of resilient and sustainable crop production systems under a changing climate at regional-to-global scales.

    Plot-level rapid screening for photosynthetic parameters using proximal hyperspectral imaging
    Meacham-Hensold, Katherine ; Fu, Peng ; Wu, Jin ; Serbin, Shawn ; Montes, Christopher M. ; Ainsworth, Elizabeth ; Guan, Kaiyu ; Dracup, Evan ; Pederson, Taylor ; Driever, Steven ; Bernacchi, Carl - \ 2020
    Journal of Experimental Botany 71 (2020)7. - ISSN 0022-0957 - p. 2312 - 2328.
    Field phenotyping - food security - hyperspectral imaging - photosynthesis - proximal sensing - spectral reflectance

    Photosynthesis is currently measured using time-laborious and/or destructive methods which slows research and breeding efforts to identify crop germplasm with higher photosynthetic capacities. We present a plot-level screening tool for quantification of photosynthetic parameters and pigment contents that utilizes hyperspectral reflectance from sunlit leaf pixels collected from a plot (∼2 m×2 m) in <1 min. Using field-grown Nicotiana tabacum with genetically altered photosynthetic pathways over two growing seasons (2017 and 2018), we built predictive models for eight photosynthetic parameters and pigment traits. Using partial least squares regression (PLSR) analysis of plot-level sunlit vegetative reflectance pixels from a single visible near infra-red (VNIR) (400-900 nm) hyperspectral camera, we predict maximum carboxylation rate of Rubisco (Vc,max, R2=0.79) maximum electron transport rate in given conditions (J1800, R2=0.59), maximal light-saturated photosynthesis (Pmax, R2=0.54), chlorophyll content (R2=0.87), the Chl a/b ratio (R2=0.63), carbon content (R2=0.47), and nitrogen content (R2=0.49). Model predictions did not improve when using two cameras spanning 400-1800 nm, suggesting a robust, widely applicable and more 'cost-effective' pipeline requiring only a single VNIR camera. The analysis pipeline and methods can be used in any cropping system with modified species-specific PLSR analysis to offer a high-throughput field phenotyping screening for germplasm with improved photosynthetic performance in field trials.

    Response of metal-coordination-based polyelectrolyte complex micelles to added ligands and metals
    Wang, Junyou ; Guan, Wenjun ; Tan, Tianhong ; Saggiomo, Vittorio ; Cohen Stuart, Martien A. ; Velders, Aldrik H. - \ 2020
    Soft Matter 16 (2020)12. - ISSN 1744-683X - p. 2953 - 2960.

    Polyelectrolyte complex based micelles have attracted significant attention due to their potential regarding bio-applications. Although the morphology and functions have been studied extensively, dynamic properties, particularly component exchange with other surrounding molecules, have remained elusive to date. Here, we show how micelles based on metal-ligand coordination complex coacervate-core micelles (M-C3Ms) respond to addition of extra ligand and metal ions. The micelles are prepared from a polycationic-neutral diblock copolymer and an anionic coordination polyelectrolyte, which is obtained by coordination between metal ions (lanthanides Ln3+ and Zn2+) and a bis-ligand (LEO) containing two dipicolinic acid (DPA) groups connected by a tetra-ethylene oxide spacer (4EO). Our findings show that the bis-ligand LEO is essential for the growth of coordination polymers and consequently the formation of micelles, leading to equilibrium structures with the same micellar composition and structure independent of the order of mixing. In other words, adding single DPA has no effect on the formed M-C3Ms. As for metal exchange, we find that added Zn2+ can replace some of the Ln3+ from Ln-C3Ms, leading to a hybrid coordination structure with both Ln3+ and Zn2+. We find that component exchange occurs in these coordination polyelectrolyte micelles, but it is more favorable in the direction of replacing the weak binding components with strong ones. Hence, the designed M-C3Ms based on the strong binding components, such as Ln-C3Ms, shall be relatively stable in biological surroundings, paving the way for the application of such particles as bio-imaging probes.

    The tonsillar microbiome of Streptococcus suis diseased piglets
    Fredriksen, Simen ; Neila, Carlos ; Fernandes de Oliveira, Isabela ; Murray, G. ; Guan, X. ; Ferrando, M.L. ; Correa-Fiz, Flor ; Baarlen, P. van; Aragon, Virginia ; Wells, J.M. - \ 2020
    In: WIAS Annual Conference 2020. - WIAS - p. 22 - 22.
    microbiome is important in shaping the host immune system as well as providing direct protection against pathogens by colonization resistance. Streptococcus suis is one of the most abundant bacteria in the oral cavity of pigs, but also a zoonotic pathogen of increasing importance. S. suis is a complex pathogen with a large diversity of pathogenic and commensal strains, and there is no cross protective vaccine. Pathogenic strains are hypothesized to enter the host via the palatine tonsils, a lymphoid organ colonized by S. suisin virtually all pigs. In order to enter the host bloodstream via the tonsils, pathogenic S. suis strains first need to colonize the tonsillar biofilm. It is possible that this is facilitated during microbial dysbiosis when there is reduced competition from commensal bacteria. We have utilized both amplic on and shotgun sequencing approaches to quantify the tonsillar microbiome of S. suis diseased piglets and healthy controls. We find microbiome compositionand diversity to differ between controls and symptomatic animals, even weeks before disease occurrence. The tonsils of symptomatic animals also contain a higher relative abundance of genes that are conserved in disease-associated S. suis strains but lacking in commensals. Moreover, we find non-symptomatic litter mates of diseased piglets to have an intermediate microbiome profile. We hypothesize that some sows provide piglets with a disease-prone microbiome, possibly due to direct transmission of an unhealthy microbiome or deficient colostrum. Within our consortium we are utilizing the results from this study in vaccine and probiotics development.
    Assessing the sensitivity and repeatability of permanganate oxidizable carbon as a soil health metric: An interlab comparison across soils
    Wade, Jordon ; Maltais-Landry, Gabriel ; Lucas, Dawn E. ; Bongiorno, Giulia ; Bowles, Timothy M. ; Calderón, Francisco J. ; Culman, Steve W. ; Daughtridge, Rachel ; Ernakovich, Jessica G. ; Fonte, Steven J. ; Giang, Dinh ; Herman, Bethany L. ; Guan, Lindsey ; Jastrow, Julie D. ; Loh, Bryan H.H. ; Kelly, Courtland ; Mann, Meredith E. ; Matamala, Roser ; Miernicki, Elizabeth A. ; Peterson, Brandon ; Pulleman, Mirjam M. ; Scow, Kate M. ; Snapp, Sieglinde S. ; Thomas, Vanessa ; Tu, Xinyi ; Wang, Daoyuan ; Jelinski, Nicolas A. ; Liles, Garrett C. ; Barrios-Masias, Felipe H. ; Rippner, Devin A. ; Silveira, Maria L. ; Margenot, Andrew J. - \ 2020
    Geoderma 366 (2020). - ISSN 0016-7061

    Soil organic matter is central to the soil health framework. Therefore, reliable indicators of changes in soil organic matter are essential to inform land management decisions. Permanganate oxidizable carbon (POXC), an emerging soil health indicator, has shown promise for being sensitive to soil management. However, strict standardization is required for widespread implementation in research and commercial contexts. Here, we used 36 soils—three from each of the 12 USDA soil orders—to determine the effects of sieve size and soil mass of analysis on POXC results. Using replicated measurements across 12 labs in the US and the EU (n = 7951 samples), we quantified the relative importance of 1) variation between labs, 2) variation within labs, 3) effect soil mass, and 4) effect of soil sieve size on the repeatability of POXC. We found a wide range of overall variability in POXC values across labs (0.03 to 171.8%; mean = 13.4%), and much of this variability was attributable to within-lab variation (median = 6.5%) independently of soil mass or sieve size. Greater soil mass (2.5 g) decreased absolute POXC values by a mean of 177 mg kg−1 soil and decreased analytical variability by 6.5%. For soils with organic carbon (SOC) >10%, greater soil mass (2.5 g) resulted in more frequent POXC values above the limit of detection whereas the lower soil mass (0.75 g) resulted in POXC values below the limit of detection for SOC contents <5%. A finer sieve size increased absolute values of POXC by 124 mg kg−1 while decreasing the analytical variability by 1.8%. In general, soils with greater SOC contents had lower analytical variability. These results point to potential standardizations of the POXC protocol that can decrease the variability of the metric. We recommend that the POXC protocol be standardized to use 2.5 g for soils <10% SOC. Sieve size was a relatively small contributor to analytical variability and therefore we recommend that this decision be tailored to the study purpose. Tradeoffs associated with these standardizations can be mitigated, ultimately providing guidance on how to standardize POXC for routine analysis.

    Climate impact on US Potato yield, water demand and nutrient uptake
    Zhao, C. ; Stöckle, Claudio O. ; Karimi, T. ; Nelson, R. ; Evert, F.K. van; Pronk, A.A. ; Riddle, A.A. ; Marshall, E. ; Raymundo, R. ; Li, Y. ; Guan, K. ; Gustafson, D. ; Hoogenboom, G. ; Asseng, S. - \ 2019
    Potatoes are a main vegetable crop in the United States with an annual production of 4 million tons (dry tuber) grown on 0.4 million ha. Previous studies in the US have shown climate change might reduce US major grain crop productions, but less is known on US potatoes. Climate change impacts on potatoes in 32 main potatoes growing districts in the US were estimated with an ensemble of five process-based models (SIMPLE, CropSyst, LINTUL-POTATO-DSS, EPIC and DSSAT-Substor-Potato) and one statistical model under RCP8.5 scenario and five Global climate models. The crop models simulated the similar results to the historical observed yield data and field CO2 enhancement experiments. Ensemble median show that by 2030s or 2050s, climate change would reduce the potato yield in parts of Northwest and Mid-west, but increase yield in other areas.Adaptation with earlier planting date could offset the yield reductions in parts of in Northwest and Mid-west, and further increase potato yield in the places with the positive impact. CropSyst simulated Potato water demand would decrease by a spatial of 0~30% by 2030s/2050s, with more reductions in west regions than the east. The simulations indicate that climate changes by 2030s/2050s increase nutrient (nitrogen, phosphorus and potassium) uptake except the Northwest US, similar to the pattern of yield changes. For the whole US, the ensemble shows a 7.8% (10.0%) increase of potato yield by 2030s (2050s), with another 2.3%~4.9% of yield increase if earlier planting is implemented. Potato transpiration would decrease by 5%~15%, whereas the nutrients uptake would increase by 5%~10%.
    Inhibition of oil digestion in Pickering emulsions stabilized by oxidized cellulose nanofibrils for low-calorie food design
    Liu, Bin ; Zhu, Yanli ; Tian, Jingnan ; Guan, Tong ; Li, Dan ; Bao, Cheng ; Norde, Willem ; Wen, Pengcheng ; Li, Yuan - \ 2019
    RSC Advances : An international journal to further the chemical sciences 9 (2019)26. - ISSN 2046-2069 - p. 14966 - 14973.

    Celluloses are renewable and biodegradable natural resources. The application of celluloses as oil-in-water Pickering emulsifiers is still quite limited. In this paper, cellulose nanofibrils (CNFs) with oxidation degrees (DOs) of 52.8% and 92.7% (DO50 and DO90) were obtained from TEMPO-mediate oxidation for microcrystalline cellulose (MC). The production of carboxyl groups of CNFs were confirmed by FT-IR and 13C solid-NMR. CNF-stabilized O/W Pickering emulsion showed excellent colloidal stability compared with un-oxidized cellulose by Turbiscan stability analysis. Additionally, CNF-stabilized Pickering emulsions showed stable colloidal properties in simulated intestinal fluid (SIF). Most importantly, in vitro fatty acid release kinetics under SIF showed that CNFs have strong inhibitory lipid digestion behavior. Our results suggest that the oxidation modification not only improves their emulsification activity but also promotes their application in oil digestion inhibition, providing inspiration for designing and developing low-calorie food products.

    Reduction of low arsenic concentrations in drinking water to below 1 µg L−1 by adsorption onto granular iron (Hydr)oxides
    Jeworrek, A. ; Ahmad, A. ; Hofs, B. ; Mook, J. van; Wal, A. van der - \ 2019
    In: Environmental Arsenic in a ChangingWorld. - CRC Press/Balkema - ISBN 9781138486096 - p. 593 - 594.

    Arsenic in drinking water should be reduced as much as possible, because it is amongst carcinogenic substances. FerroSorp® Plus, Huijbergen and Spannenburg GIH could reduce As(V) levels in Ouddorp water below the desired 1 µg L−1. Particularly Huijbergen GIH had according to non-linear Freundlich modeling the higher KF value, translating into a potentially higher effective adsorption capacity. One of the characteristics that probably determines the success of a GIH is its physical properties. Since the effective adsorption capacity increases with higher initial As(V) concentrations, Huijbergen GIH is a promising adsorbent to reduce a wide range of arsenic concentrations from drinking water. Therefore, this affordable technology is not only reducing ultra-low arsenic concentrations to even lower concentrations in Ouddorp water but is also promising for developing countries that are seriously affected by high concentrations of arsenic in their drinking water.

    Comparison of smoking-related DNA methylation between newborns from prenatal exposure and adults from personal smoking
    Sikdar, Sinjini ; Joehanes, Roby ; Joubert, Bonnie R. ; Xu, Cheng Jian ; Vives-Usano, Marta ; Rezwan, Faisal I. ; Felix, Janine F. ; Ward, James M. ; Guan, Weihua ; Richmond, Rebecca C. ; Brody, Jennifer A. ; Küpers, Leanne K. ; Baïz, Nour ; Håberg, Siri E. ; Smith, Jennifer A. ; Reese, Sarah E. ; Aslibekyan, Stella ; Hoyo, Cathrine ; Dhingra, Radhika ; Markunas, Christina A. ; Xu, Tao ; Reynolds, Lindsay M. ; Just, Allan C. ; Mandaviya, Pooja R. ; Ghantous, Akram ; Bennett, Brian D. ; Wang, Tianyuan ; Consortium, The Bios ; Bakulski, Kelly M. ; Melen, Erik ; Zhao, Shanshan ; Jin, Jianping ; Herceg, Zdenko ; Meurs, Joyce Van; Taylor, Jack A. ; Baccarelli, Andrea A. ; Murphy, Susan K. ; Liu, Yongmei ; Munthe-Kaas, Monica Cheng ; Deary, Ian J. ; Nystad, Wenche ; Waldenberger, Melanie ; Annesi-Maesano, Isabella ; Conneely, Karen ; Jaddoe, Vincent W.V. ; Arnett, Donna ; Snieder, Harold ; Kardia, Sharon L.R. ; Relton, Caroline L. ; Ong, Ken K. ; Ewart, Susan ; Moreno-Macias, Hortensia ; Romieu, Isabelle ; Sotoodehnia, Nona ; Fornage, Myriam ; Motsinger-Reif, Alison ; Koppelman, Gerard H. ; Bustamante, Mariona ; Levy, Daniel ; London, Stephanie J. - \ 2019
    Epigenomics 11 (2019)13. - ISSN 1750-1911 - p. 1487 - 1500.
    cigarette smoking - epigenetics - infant - maternal exposure - methylation

    Aim: Cigarette smoking influences DNA methylation genome wide, in newborns from pregnancy exposure and in adults from personal smoking. Whether a unique methylation signature exists for in utero exposure in newborns is unknown. Materials & methods: We separately meta-analyzed newborn blood DNA methylation (assessed using Illumina450k Beadchip), in relation to sustained maternal smoking during pregnancy (9 cohorts, 5648 newborns, 897 exposed) and adult blood methylation and personal smoking (16 cohorts, 15907 participants, 2433 current smokers). Results & conclusion: Comparing meta-analyses, we identified numerous signatures specific to newborns along with many shared between newborns and adults. Unique smoking-associated genes in newborns were enriched in xenobiotic metabolism pathways. Our findings may provide insights into specific health impacts of prenatal exposure on offspring.

    NSs Filament Formation Is Important but Not Sufficient for RVFV Virulence In Vivo
    Li, Shufen ; Zhu, Xiangtao ; Guan, Zhenqiong ; Huang, Wenfeng ; Zhang, Yulan ; Kortekaas, Jeroen ; Lozach, Pierre Yves ; Peng, Ke - \ 2019
    Viruses 11 (2019)9. - ISSN 1999-4915
    filament - NSs - reverse genetics system - RVFV - virulence

    Rift Valley fever virus (RVFV) is a mosquito-borne phlebovirus that represents as a serious health threat to both domestic animals and humans. The viral protein NSs is the key virulence factor of RVFV, and has been proposed that NSs nuclear filament formation is critical for its virulence. However, the detailed mechanisms are currently unclear. Here, we generated a T7 RNA polymerase-driven RVFV reverse genetics system based on a strain imported into China (BJ01). Several NSs mutations (T1, T3 and T4) were introduced into the system for investigating the correlation between NSs filament formation and virulence in vivo. The NSs T1 mutant showed distinct NSs filament in the nuclei of infected cells, the T3 mutant diffusively localized in the cytoplasm and the T4 mutant showed fragmented nuclear filament formation. Infection of BALB/c mice with these NSs mutant viruses revealed that the in vivo virulence was severely compromised for all three NSs mutants, including the T1 mutant. This suggests that NSs filament formation is not directly correlated with RVFV virulence in vivo. Results from this study not only shed new light on the virulence mechanism of RVFV NSs but also provided tools for future in-depth investigations of RVFV pathogenesis and anti-RVFV drug screening.

    Contribution of methylation regulation of MpDREB2A promoter to drought resistance of Mauls prunifolia
    Li, Xuewei ; Xie, Yinpeng ; Lu, Liyuan ; Yan, Mingjia ; Fang, Nan ; Xu, Jidi ; Wang, Liping ; Yan, Yan ; Zhao, Tao ; Nocker, Steve van; Ma, Fengwang ; Liang, Dong ; Guan, Qingmei - \ 2019
    Plant and Soil 441 (2019)1-2. - ISSN 0032-079X - p. 15 - 32.
    ChIP-seq - DNA methylation - DREB2A - Drought resistance - Gene expression - Malus

    Background and aims: Malus prunifolia (Chinese name: Fu Ping Qiu Zi), a wild relative of cultivated apple (Malus x domestica Borkh), is extremely resistant to drought compared with domesticated cultivars, such as ‘Golden Delicious’. However, the molecular mechanisms underlying drought resistance of M. prunifolia have not been characterized. This study investigates a new regulatory mechanism to improve apple drought resistance. Methods: M. prunifolia and ‘Golden Delicious’ were each grafted on M. hupehensis for gene expression analysis. The methylation level of the DREB2A promoter was determined by bisulfite sequencing and ChIP-qPCR. Chromatin immunoprecipitation sequencing (ChIP-seq) was used to identify target genes of MpDREB2A in apple. Results: The exposure to drought stress stimulated the expression level of DREB2A gene more than 100-fold in M. prunifolia, but only 16-fold in ‘Golden Delicious’. This difference in gene expression could not be explained in terms of difference in leaf relative water content. Correspondingly, the methylation level of M. prunifolia DREB2A (MpDREB2A) promoter region was significantly reduced. Additionally, MpDREB2A conferred enhanced drought resistance when ectopically expressed in Arabidopsis. Over 2800 potential downstream target genes of MpDREB2A were identified by ChIP-seq and these downstream genes have diverse potential functions related to stress resistance. Conclusions: Methylation regulation in promoter of MpDREB2A may contribute to the drought resistance of M. prunifolia.

    Contrasting effects of host species and phylogenetic diversity on the occurrence of HPAI H5N1 in European wild birds
    Huang, Zheng Y.X. ; Xu, Chi ; Langevelde, Frank van; Ma, Yuying ; Langendoen, Tom ; Mundkur, Taej ; Si, Yali ; Tian, Huaiyu ; Kraus, Robert H.S. ; Gilbert, Marius ; Han, Guan Zhu ; Ji, Xiang ; Prins, Herbert H.T. ; Boer, Willem F. de - \ 2019
    Journal of Animal Ecology 88 (2019)7. - ISSN 0021-8790 - p. 1044 - 1053.
    avian influenza - community composition - dilution effect - diversity–disease relationship - phylogenetic distance - waterfowl

    Studies on the highly pathogenic avian influenza (HPAI) H5N1 suggest that wild bird migration may facilitate its long-distance spread, yet the role of wild bird community composition in its transmission risk remains poorly understood. Furthermore, most studies on the diversity–disease relationship focused on host species diversity without considering hosts’ phylogenetic relationships, which may lead to rejecting a species diversity effect when the community has host species that are only distantly related. Here, we explored the influence of waterbird community composition for determining HPAI H5N1 occurrence in wild birds in a continental-scale study across Europe. In particular, we tested the diversity–disease relationship using both host species diversity and host phylogenetic diversity. Our results provide the first demonstration that host community composition—compared with previously identified environmental risk factors—can also effectively explain the spatial pattern of H5N1 occurrence in wild birds. We further show that communities with more higher risk host species and more closely related species have a higher risk of H5N1 outbreaks. Thus, both host species diversity and community phylogenetic structure, in addition to environmental factors, jointly influence H5N1 occurrence. Our work not only extends the current theory on the diversity–disease relationship, but also has important implications for future monitoring of H5N1 and other HPAI subtypes.

    Two large-effect QTLs, Ma and Ma3, determine genetic potential for acidity in apple fruit : breeding insights from a multi-family study
    Verma, S. ; Evans, K. ; Guan, Y. ; Luby, J.J. ; Rosyara, U.R. ; Howard, N.P. ; Bassil, N. ; Bink, M.C.A.M. ; Weg, W.E. van de; Peace, C.P. - \ 2019
    Tree Genetics and Genomes 15 (2019)2. - ISSN 1614-2942
    FlexQTL™ - Malic acid - Malus × domestica - Pedigree-Based Analysis - RosBREED

    Acidity is a critical component of the apple fruit consumption experience. In previous biparental family studies, two large-effect acidity QTLs were reported using freshly harvested fruit. Objectives of this study were to determine the number and location of QTLs for acidity variation in a large apple breeding program and ascertain the quantitative effects and breeding relevance of QTL allelic combinations at harvest and after commercially relevant periods of cold storage. Pedigree-connected germplasm of 16 full-sib families representing nine important breeding parents, genotyped for the 8K SNP array, was assessed for titratable acidity at harvest and after 10- and 20-week storage treatments, for three successive seasons. Using pedigree-based QTL mapping software, FlexQTL™, evidence was found for only two QTLs, on linkage groups 16 (the reported Ma locus) and LG 8 (here called Ma3) that jointly explained 66 ± 5% of the phenotypic variation. An additive allele dosage model for the two QTLs effectively explained most acidity variation, with an average of + 1.8 mg/L at harvest per high-acidity allele. The more high-acidity alleles, the faster the depletion with storage, with all combinations appearing to eventually converge to a common baseline. All parent cultivars and selections had one or two of the four possible high-acidity alleles. Each QTL had a rare second high-acidity allele with stronger or reduced effect. Diagnostic SNP markers were identified for QTL alleles derived from distinct sources. Combined QTL effects highlighted utility of the DNA-based information in new cultivar development for targeting desired fruit acidity levels before or after storage.

    Editors’ foreword
    Zhu, Yong Guan ; Guo, Huaming ; Bhattacharya, Prosun ; Bundschuh, Jochen ; Ahmad, Arslan ; Naidu, Ravi - \ 2018
    In: Environmental Arsenic in a ChangingWorld. - Beijing : CRC Press/Balkema (Environmental Arsenic in a ChangingWorld - 7th International Congress and Exhibition Arsenic in the Environment, 2018 ) - ISBN 9781138486096 - p. xlv - xlvi.
    Editors’ foreword
    Zhu, Yong Guan ; Guo, Huaming ; Bhattacharya, Prosun ; Bundschuh, Jochen ; Ahmad, Arslan ; Naidu, Ravi - \ 2018
    In: Environmental Arsenic in a Changing World. - CRC Press/Balkema - ISBN 9781138486096 - p. xlv - xlvi.
    Arsenic removal to <1 µg l−1 by coprecipitation with in-situ generated Fe(III) precipitates with and without advanced pre-oxidation
    Ahmad, A. ; Mook, J. van; Schaaf, B. ; Wal, A. van der - \ 2018
    In: Environmental Arsenic in a ChangingWorld - 7th International Congress and Exhibition Arsenic in the Environment, 2018. - CRC Press/Balkema (Environmental Arsenic in a ChangingWorld - 7th International Congress and Exhibition Arsenic in the Environment, 2018 ) - ISBN 9781138486096 - p. 591 - 592.

    The aim of this study is to investigate removal of low As concentrations from groundwater at a Drinking Water Treatment Plant (DWTP) in The Netherlands in order to achieve <1 µg L−1 As in produced drinking water. Two iron based emerging technologies, both relying on in-situ generated Fe(III) precipitates for As adsorption, were investigated. These include: 1) Advanced Oxidation-Coprecipitation-Filtration (AOCF) and 2) Coprecipitation prior to ultrafiltration (C-UF). We show that most of the As removal occurs in the top half of a Rapid Sand Filter (RSF) bed. In this part we also observe the conversion of As(III) into As(V). The mechanism of As(III) oxidation to As(V) in the RSF is still not understood, however we hypothesize that either the manganese oxides or the biological activity in the filter bed may be responsible for this conversion. In agreement with this observation, we also notice that drinking water only contains As(V) and that the levels of As(III) are negligible. The experiments have shown that both AOCF and C-UF are promising emerging technologies to reduce arsenic levels to below 1 µg L−1 which is the agreed target in The Netherlands between the Dutch water companies.

    Integrating arsenic in water safety planning in the Netherlands
    Wens, P. van der; Ahmad, A. - \ 2018
    In: Environmental Arsenic in a ChangingWorld - 7th International Congress and Exhibition Arsenic in the Environment, 2018. - CRC Press/Balkema (Environmental Arsenic in a ChangingWorld - 7th International Congress and Exhibition Arsenic in the Environment, 2018 ) - ISBN 9781138486096 - p. 618 - 619.

    The Dutch drinking water sector complies with the most restrictive guidelines in the world and has a long-standing history of striving for excellence in water quality standards. The Dutch Association of Drinking Water Companies (Vewin) concluded in 2015 to lower the standard on arsenic in drinking water to 1 µg L−1. Following the new recommendation Brabant Water, a major water supply company in The Netherlands developed its masterplan on arsenic reduction by analysing the presence of arsenic in the systems from source to tap. Several measures were put in place to integrate arsenic into water safety planning in order to manage the risks. The underlying cost-benefit study and its implication on water safety planning at Brabant Water is discussed in this presentation.

    Visual MINTEQ simulation for prediction of the adsorption of arsenic on ferrihydrite
    Irunde, R. ; Bhattacharya, P. ; Ijumulana, J. ; Ligate, F.J. ; Ahmad, A. ; Mtalo, F. ; Mtamba, J. - \ 2018
    In: Environmental Arsenic in a ChangingWorld - 7th International Congress and Exhibition Arsenic in the Environment, 2018. - CRC Press/Balkema (Environmental Arsenic in a ChangingWorld - 7th International Congress and Exhibition Arsenic in the Environment, 2018 ) - ISBN 9781138486096 - p. 435 - 436.

    The surface of ferrihydrite adsorbs arsenic (As) effectively. In this investigation, the As laced water samples collected from Geita and Mara regions within the Lake Victoria Basin (LVB) under DAFWAT project were simulated onVisual MINTEQ 3.1 software to determine the amount of ferrihydrite required to adsorb a given amount of As from water. Model simulations show that As concentration of ≤1 mM can be completely adsorbed by 4 g L−1 ferrihydrite. Previous studies show that the lower pH 4 to 4.5 influences adsorption, while it decreases as pH increases as well as when As concentration increases. The increase of adsorbent dose to 4 g L−1 has shown to improve As(V) adsorption on pH 5 to 8 at 100%. The amount of adsorbent can now be used for laboratory adsorption experiments by using iron-based materials or commercial ferrihydrite.

    Modeling arsenic removal by co-precipitation under variable redox conditions
    Korevaar, M.W. ; Vries, D. ; Ahmad, A. - \ 2018
    In: Environmental Arsenic in a ChangingWorld - 7th International Congress and Exhibition Arsenic in the Environment, 2018. - CRC Press/Balkema (Environmental Arsenic in a ChangingWorld - 7th International Congress and Exhibition Arsenic in the Environment, 2018 ) - ISBN 9781138486096 - p. 432 - 434.

    Drinking water companies in the Netherlands are actively investigating routes to reduce arsenic (As) to <1 µg L−1 in drinking water. Co-precipitation of As with iron during groundwater treatment is a promising method. When As(III) is present in raw water, permanganate (MnO4) can be dosed to oxidize As(III) to As(V) in order to improve As removal efficiency. The dosages of MnO4 and Fe(III) to achieve <1 µg L−1 As in the treatment effluents depend on the composition of raw water. The coprecipitation of As(III) and As(V) with ferrihydrite under variable raw water composition and redox environments, controlled by oxygen (O2) or MnO4 is modeled in this study by the generalized double layer model, and redox equilibrium reactions. Results show that the pH of the treatment process is critical to determine the As removal efficiency. At pH = 8 the highest As removal is obtained, followed by pH = 6 while pH = 7 gives the least removal. HCO3, PO4 and H4 SO4 hamper the adsorption of As(V). In future work, the model outcome will be assessed by experiments. Furthermore, the model will be extended with oxidation kinetics in case oxidation (by e.g. oxygen) occurs at a slower rate than the (mean) residence time of the water in the process.

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