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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Nonlinear responses of soil nematode community composition to increasing aridity
Xiong, Dan ; Wei, Cun Zheng ; Wubs, Jasper E.R. ; Veen, G.J. ; Liang, Wenju ; Wang, Xiaobo ; Li, Qi ; Putten, Wim H. Van der; Han, Xingguo - \ 2019
Global Ecology and Biogeography (2019). - ISSN 1466-822X
aridity - biodiversity - global climate change - grassland transect - nonlinear response - soil nematode community

Aim: Increasing aridity under global change is predicted to have a profound impact on the structure and functioning of terrestrial ecosystems, yet we have a poor understanding of how belowground communities respond. In order to understand the longer term responses of different trophic levels in the soil food web to increasing aridity, we investigated the abundance, richness and community similarity of the soil nematode community along a 3,200 km aridity gradient. Location: A transect across semi-arid and arid grasslands in Northern China, where the aridity ranges from.43 to.97. Time period: July and August 2012. Major taxa studied: Soil-borne Nematoda. Methods: We used generalized additive (mixed) models to analyse the abundance, richness and community similarity patterns of soil nematodes. We used structural equation modelling (SEM) to disentangle the direct and indirect environmental drivers (aridity, soil and plant variables) of the nematode community. Results: The abundance, richness and similarity of nematode communities declined nonlinearly with increasing aridity. The most pronounced decline in nematode richness and community similarity occurred in arid conditions (aridity >.80). However, the shape of the response to aridity differed among nematode feeding groups. In arid conditions, the abundance and richness of bacterial feeders were less sensitive to changes in aridity than for fungal feeders. The SEM analysis revealed that nematode community responses to aridity were not mediated via changes in plant and soil variables, but instead were affected directly by aridity. Main conclusions: Our results showed that in mesic grasslands, increasing aridity primarily caused a decline in nematode abundance, whereas increasing aridity in xeric grasslands led to a loss of nematode diversity. The nonlinear responses of nematodes to aridity could also result in nonlinear shifts in ecosystem functioning, because soil nematodes operate at various trophic levels in the soil food web, thereby influencing the performance of plants, soil biodiversity and biogeochemical cycling.

Mito-docking: A Novel In Vivo Method to Detect Protein–Protein Interactions
Shao, Wei ; He, Lihong ; Deng, Fei ; Wang, Hualin ; Vlak, Just M. ; Hu, Zhihong ; Wang, Manli - \ 2019
Small Methods 3 (2019)10. - ISSN 2366-9608
in vivo - method - Mito-docking - nuclear import - protein–protein interactions

Many methods have been developed to detect protein–protein interactions (PPIs) and explore cellular processes. However, effective methods for detecting complicated PPIs under physical conditions are still in demand. Here, a simple and efficient mitochondria-docking (Mito-docking) method for PPI detection in vivo is developed. The strategy is to anchor a “bait” protein to mitochondrial outer membrane (MOM), and then trap the “prey” protein onto MOM. In this way, interacting signals are enriched to allow easy detection. This method efficiently detects the well-known interaction between two G protein subunits (Gγ2 with Gβ1) and is successfully applied to investigate the recognition of importin α superfamily members for the classical nuclear localization signal (NLS) of simian virus 40 (SV40) large T antigen, which are highly dynamic and not easily visualized by conventional methods. As far as is known, this is the first time that the interaction between human importin α receptors with NLSs has been visualized. The results prove that Mito-docking can be used as a simple, straightforward, and intuitive method to study PPIs qualitatively and quantitatively in vivo.

A global synthesis reveals biodiversity-mediated benefits for crop production
Dainese, Matteo ; Martin, Emily A. ; Aizen, Marcelo A. ; Albrecht, Matthias ; Bartomeus, Ignasi ; Bommarco, Riccardo ; Carvalheiro, Luisa G. ; Chaplin-Kramer, Rebecca ; Gagic, Vesna ; Garibaldi, Lucas A. ; Ghazoul, Jaboury ; Grab, Heather ; Jonsson, Mattias ; Karp, Daniel S. ; Kennedy, Christina M. ; Kleijn, David ; Kremen, Claire ; Landis, Douglas A. ; Letourneau, Deborah K. ; Marini, Lorenzo ; Poveda, Katja ; Rader, Romina ; Smith, Henrik G. ; Tscharntke, Teja ; Andersson, Georg K.S. ; Badenhausser, Isabelle ; Baensch, Svenja ; Bezerra, Antonio D.M. ; Bianchi, Felix J.J.A. ; Boreux, Virginie ; Bretagnolle, Vincent ; Caballero-Lopez, Berta ; Cavigliasso, Pablo ; Ćetković, Aleksandar ; Chacoff, Natacha P. ; Classen, Alice ; Cusser, Sarah ; Silva E Silva, Felipe D. Da; Groot, A. de; Dudenhöffer, Jan H. ; Ekroos, Johan ; Fijen, Thijs ; Franck, Pierre ; Freitas, Breno M. ; Garratt, Michael P.D. ; Gratton, Claudio ; Hipólito, Juliana ; Holzschuh, Andrea ; Hunt, Lauren ; Iverson, Aaron L. ; Jha, Shalene ; Keasar, Tamar ; Kim, Tania N. ; Kishinevsky, Miriam ; Klatt, Björn K. ; Klein, Alexandra Maria ; Krewenka, Kristin M. ; Krishnan, Smitha ; Larsen, Ashley E. ; Lavigne, Claire ; Liere, Heidi ; Maas, Bea ; Mallinger, Rachel E. ; Pachon, Eliana Martinez ; Martínez-Salinas, Alejandra ; Meehan, Timothy D. ; Mitchell, Matthew G.E. ; Molina, Gonzalo A.R. ; Nesper, Maike ; Nilsson, Lovisa ; O'Rourke, Megan E. ; Peters, Marcell K. ; Plećaš, Milan ; Potts, Simon G. ; L. Ramos, Davi de; Rosenheim, Jay A. ; Rundlöf, Maj ; Rusch, Adrien ; Sáez, Agustín ; Scheper, Jeroen ; Schleuning, Matthias ; Schmack, Julia M. ; Sciligo, Amber R. ; Seymour, Colleen ; Stanley, Dara A. ; Stewart, Rebecca ; Stout, Jane C. ; Sutter, Louis ; Takada, Mayura B. ; Taki, Hisatomo ; Tamburini, Giovanni ; Tschumi, Matthias ; Viana, Blandina F. ; Westphal, Catrin ; Willcox, Bryony K. ; Wratten, Stephen D. ; Yoshioka, Akira ; Zaragoza-Trello, Carlos ; Zhang, Wei ; Zou, Yi ; Steffan-Dewenter, Ingolf - \ 2019
Science Advances 5 (2019)10. - ISSN 2375-2548

Human land use threatens global biodiversity and compromises multiple ecosystem functions critical to food production. Whether crop yield-related ecosystem services can be maintained by a few dominant species or rely on high richness remains unclear. Using a global database from 89 studies (with 1475 locations), we partition the relative importance of species richness, abundance, and dominance for pollination; biological pest control; and final yields in the context of ongoing land-use change. Pollinator and enemy richness directly supported ecosystem services in addition to and independent of abundance and dominance. Up to 50% of the negative effects of landscape simplification on ecosystem services was due to richness losses of service-providing organisms, with negative consequences for crop yields. Maintaining the biodiversity of ecosystem service providers is therefore vital to sustain the flow of key agroecosystem benefits to society.

ABA-mediated regulation of leaf and root hydraulic conductance in tomato grown at elevated CO2 is associated with altered gene expression of aquaporins
Fang, Liang ; Abdelhakim, Lamis Osama Anwar ; Hegelund, Josefine Nymark ; Li, Shenglan ; Liu, Jie ; Peng, Xiaoying ; Li, Xiangnan ; Wei, Zhenhua ; Liu, Fulai - \ 2019
Horticulture Research 6 (2019)1. - ISSN 2052-7276

Elevated CO2 concentration in the air (e[CO2]) decreases stomatal density (SD) and stomatal conductance (gs) where abscisic acid (ABA) may play a role, yet the underlying mechanism remains largely elusive. We investigated the effects of e[CO2] (800 ppm) on leaf gas exchange and water relations of two tomato (Solanum lycopersicum) genotypes, Ailsa Craig (WT) and its ABA-deficient mutant (flacca). Compared to plants grown at ambient CO2 (400 ppm), e[CO2] stimulated photosynthetic rate in both genotypes, while depressed the gs only in WT. SD showed a similar response to e[CO2] as gs, although the change was not significant. e[CO2] increased leaf and xylem ABA concentrations and xylem sap pH, where the increases were larger in WT than in flacca. Although leaf water potential was unaffected by CO2 growth environment, e[CO2] lowered osmotic potential, hence tended to increase turgor pressure particularly for WT. e[CO2] reduced hydraulic conductance of leaf and root in WT but not in flacca, which was associated with downregulation of gene expression of aquaporins. It is concluded that ABA-mediated regulation of gs, SD, and gene expression of aquaporins coordinates the whole-plant hydraulics of tomato grown at different CO2 environments.

Prediction of metabolic status of dairy cows in early lactation with on-farm cow data and machine learning algorithms
Xu, Wei ; Knegsel, Ariette T.M. van; Vervoort, Jacques J.M. ; Bruckmaier, Rupert M. ; Hoeij, Renny J. van; Kemp, Bas ; Saccenti, Edoardo - \ 2019
Journal of Dairy Science 102 (2019)11. - ISSN 0022-0302 - p. 10186 - 10201.
cattle - cluster analysis - energy metabolism - Random Forest

Metabolic status of dairy cows in early lactation can be evaluated using the concentrations of plasma β-hydroxybutyrate (BHB), free fatty acids (FFA), glucose, insulin, and insulin-like growth factor 1 (IGF-1). These plasma metabolites and metabolic hormones, however, are difficult to measure on farm. Instead, easily obtained on-farm cow data, such as milk production traits, have the potential to predict metabolic status. Here we aimed (1) to investigate whether metabolic status of individual cows in early lactation could be clustered based on their plasma values and (2) to evaluate machine learning algorithms to predict metabolic status using on-farm cow data. Through lactation wk 1 to 7, plasma metabolites and metabolic hormones of 334 cows were measured weekly and used to cluster each cow into 1 of 3 clusters per week. The cluster with the greatest plasma BHB and FFA and the lowest plasma glucose, insulin, and IGF-1 was defined as poor metabolic status; the cluster with the lowest plasma BHB and FFA and the greatest plasma glucose, insulin, and IGF-1 was defined as good metabolic status; and the intermediate cluster was defined as average metabolic status. Most dairy cows were classified as having average or good metabolic status, and a limited number of cows had poor metabolic status (10–50 cows per lactation week). On-farm cow data, including dry period length, parity, milk production traits, and body weight, were used to predict good or average metabolic status with 8 machine learning algorithms. Random Forest (error rate ranging from 12.4 to 22.6%) and Support Vector Machine (SVM; error rate ranging from 12.4 to 20.9%) were the top 2 best-performing algorithms to predict metabolic status using on-farm cow data. Random Forest had a higher sensitivity (range: 67.8–82.9% during wk 1 to 7) and negative predictive value (range: 89.5–93.8%) but lower specificity (range: 76.7–88.5%) and positive predictive value (range: 58.1–78.4%) than SVM. In Random Forest, milk yield, fat yield, protein percentage, and lactose yield had important roles in prediction, but their rank of importance differed across lactation weeks. In conclusion, dairy cows could be clustered for metabolic status based on plasma metabolites and metabolic hormones. Moreover, on-farm cow data can predict cows in good or average metabolic status, with Random Forest and SVM performing best of all algorithms.

Soil heterogeneity and plant species diversity in experimental grassland communities: contrasting effects of soil nutrients and pH at different spatial scales
Xue, Wei ; Bezemer, Martijn T. ; Berendse, Frank - \ 2019
Plant and Soil 442 (2019)1-2. - ISSN 0032-079X - p. 497 - 509.
Focal scale - Patch size - Plant community composition - Plant species diversity - Soil heterogeneity - Soil nutrients and pH

Background and aims: Current knowledge of soil heterogeneity-diversity relationships (HDR) is largely based on studies manipulating single factor, but the advancements in HDR may require a comprehensive experiment incorporating multiple factors. Methods: We conducted a three-year field experiment in which a seed mixture of 16 common grassland species was sown in plots with heterogeneous soils consisting of small (10 cm × 10 cm) or large patches (30 cm × 30 cm) of low and high nutrients or low and high pH, and homogeneous soils with an even mixture of low and high nutrient/pH soils. Soil nutrients and pH were manipulated in separate treatments. We determined plant species richness and diversity at two focal scales (40 cm × 40 cm plot-scale and 10 cm × 10 cm patch-scale). Results: Plot-scale richness and diversity were not influenced by soil heterogeneity, but patch-scale richness was lower in plots with heterogeneous nutrients than in plots where nutrients were distributed homogeneously. There was no difference between the two heterogeneous nutrient soils with different grain sizes. Patch-scale diversity was higher in heterogeneous pH soils of large patch size than in heterogeneous pH soils of small patch size or the homogeneous pH soil at the final harvest. Species richness and diversity quantified at both plot and patch scales declined in all soils over time. Conclusions: The influence of soil heterogeneity on plant species diversity depends on whether the soil varies in nutrients or pH, and on the temporal-spatial scale at which species diversity and soil heterogeneity are measured. These results indicate that soil heterogeneity has the potential to promote plant coexistence and future HDR studies should consider multiple soil factors at various temporal-spatial scales.

Correction to: Genetic variant predictors of gene expression provide new insight into risk of colorectal cancer
Bien, Stephanie A. ; Su, Yu Ru ; Conti, David V. ; Harrison, Tabitha A. ; Qu, Conghui ; Guo, Xingyi ; Lu, Yingchang ; Albanes, Demetrius ; Auer, Paul L. ; Banbury, Barbara L. ; Berndt, Sonja I. ; Bézieau, Stéphane ; Brenner, Hermann ; Buchanan, Daniel D. ; Caan, Bette J. ; Campbell, Peter T. ; Carlson, Christopher S. ; Chan, Andrew T. ; Chang-Claude, Jenny ; Chen, Sai ; Connolly, Charles M. ; Easton, Douglas F. ; Feskens, Edith J.M. ; Gallinger, Steven ; Giles, Graham G. ; Gunter, Marc J. ; Hampe, Jochen ; Huyghe, Jeroen R. ; Hoffmeister, Michael ; Hudson, Thomas J. ; Jacobs, Eric J. ; Jenkins, Mark A. ; Kampman, Ellen ; Kang, Hyun Min ; Kühn, Tilman ; Küry, Sébastien ; Lejbkowicz, Flavio ; Marchand, Loic Le; Milne, Roger L. ; Li, Li ; Li, Christopher I. ; Lindblom, Annika ; Lindor, Noralane M. ; Martín, Vicente ; McNeil, Caroline E. ; Melas, Marilena ; Moreno, Victor ; Newcomb, Polly A. ; Offit, Kenneth ; Pharaoh, Paul D.P. ; Potter, John D. ; Qu, Chenxu ; Riboli, Elio ; Rennert, Gad ; Sala, Núria ; Schafmayer, Clemens ; Scacheri, Peter C. ; Schmit, Stephanie L. ; Severi, Gianluca ; Slattery, Martha L. ; Smith, Joshua D. ; Trichopoulou, Antonia ; Tumino, Rosario ; Ulrich, Cornelia M. ; Duijnhoven, Fränzel J.B. van; Guelpen, Bethany Van; Weinstein, Stephanie J. ; White, Emily ; Wolk, Alicja ; Woods, Michael O. ; Wu, Anna H. ; Abeçasis, Goncalo R. ; Casey, Graham ; Nickerson, Deborah A. ; Gruber, Stephen B. ; Hsu, Li ; Zheng, Wei ; Peters, Ulrike - \ 2019
Human Genetics 138 (2019)7. - ISSN 0340-6717 - p. 789 - 791.

Every author has erroneously been assigned to the affiliation “62”. The affiliation 62 belongs to the author Graham Casey.

Flood analysis in the Wei River Basin
Gai, Lingtong - \ 2019
Wageningen University. Promotor(en): C.J. Ritsema; V. Geissen, co-promotor(en): J.P.C. Nunes; J.E.M. Baartman. - Wageningen : Wageningen University - ISBN 9789463439862 - 167
Patterns of nitrogen-fixing tree abundance in forests across Asia and America
Menge, Duncan N.L. ; Chisholm, Ryan A. ; Davies, Stuart J. ; Abu Salim, Kamariah ; Allen, David ; Alvarez, Mauricio ; Bourg, Norm ; Brockelman, Warren Y. ; Bunyavejchewin, Sarayudh ; Butt, Nathalie ; Cao, Min ; Chanthorn, Wirong ; Chao, Wei Chun ; Clay, Keith ; Condit, Richard ; Cordell, Susan ; Silva, João Batista da; Dattaraja, H.S. ; Andrade, Ana Cristina Segalin de; Oliveira, Alexandre A. de; Ouden, Jan den; Drescher, Michael ; Fletcher, Christine ; Giardina, Christian P. ; Savitri Gunatilleke, C.V. ; Gunatilleke, I.A.U.N. ; Hau, Billy C.H. ; He, Fangliang ; Howe, Robert ; Hsieh, Chang Fu ; Hubbell, Stephen P. ; Inman-Narahari, Faith M. ; Jansen, Patrick A. ; Johnson, Daniel J. ; Kong, Lee Sing ; Král, Kamil ; Ku, Chen Chia ; Lai, Jiangshan ; Larson, Andrew J. ; Li, Xiankun ; Li, Yide ; Lin, Luxiang ; Lin, Yi Ching ; Liu, Shirong ; Lum, Shawn K.Y. ; Lutz, James A. ; Ma, Keping ; Malhi, Yadvinder ; McMahon, Sean ; McShea, William ; Mi, Xiangcheng ; Morecroft, Michael ; Myers, Jonathan A. ; Nathalang, Anuttara ; Novotny, Vojtech ; Ong, Perry ; Orwig, David A. ; Ostertag, Rebecca ; Parker, Geoffrey ; Phillips, Richard P. ; Abd. Rahman, Kassim ; Sack, Lawren ; Sang, Weiguo ; Shen, Guochun ; Shringi, Ankur ; Shue, Jessica ; Su, Sheng Hsin ; Sukumar, Raman ; Fang Sun, I. ; Suresh, H.S. ; Tan, Sylvester ; Thomas, Sean C. ; Toko, Pagi S. ; Valencia, Renato ; Vallejo, Martha I. ; Vicentini, Alberto ; Vrška, Tomáš ; Wang, Bin ; Wang, Xihua ; Weiblen, George D. ; Wolf, Amy ; Xu, Han ; Yap, Sandra ; Zhu, Li ; Fung, Tak - \ 2019
Journal of Ecology 107 (2019)6. - ISSN 0022-0477 - p. 2598 - 2610.
forest - legume - nitrogen fixation - nutrient limitation - Smithsonian ForestGEO - symbiosis

Symbiotic nitrogen (N)-fixing trees can provide large quantities of new N to ecosystems, but only if they are sufficiently abundant. The overall abundance and latitudinal abundance distributions of N-fixing trees are well characterised in the Americas, but less well outside the Americas. Here, we characterised the abundance of N-fixing trees in a network of forest plots spanning five continents, ~5,000 tree species and ~4 million trees. The majority of the plots (86%) were in America or Asia. In addition, we examined whether the observed pattern of abundance of N-fixing trees was correlated with mean annual temperature and precipitation. Outside the tropics, N-fixing trees were consistently rare in the forest plots we examined. Within the tropics, N-fixing trees were abundant in American but not Asian forest plots (~7% versus ~1% of basal area and stems). This disparity was not explained by mean annual temperature or precipitation. Our finding of low N-fixing tree abundance in the Asian tropics casts some doubt on recent high estimates of N fixation rates in this region, which do not account for disparities in N-fixing tree abundance between the Asian and American tropics. Synthesis. Inputs of nitrogen to forests depend on symbiotic nitrogen fixation, which is constrained by the abundance of N-fixing trees. By analysing a large dataset of ~4 million trees, we found that N-fixing trees were consistently rare in the Asian tropics as well as across higher latitudes in Asia, America and Europe. The rarity of N-fixing trees in the Asian tropics compared with the American tropics might stem from lower intrinsic N limitation in Asian tropical forests, although direct support for any mechanism is lacking. The paucity of N-fixing trees throughout Asian forests suggests that N inputs to the Asian tropics might be lower than previously thought.

Impact of low-molecular weight organic acids on selenite immobilization by goethite: Understanding a competitive-synergistic coupling effect and speciation transformation
Fang, Dun ; Wei, Shiyong ; Xu, Yun ; Xiong, Juan ; Tan, Wenfeng - \ 2019
Science of the Total Environment 684 (2019). - ISSN 0048-9697 - p. 694 - 704.
Adsorption - Ferric selenite - Organic acids - Reduction - Selenium - Speciation transformation
© 2019 Elsevier B.V. The interactions between low-molecular weight organic acids (LMWOAs)and selenium (Se)on mineral/water interfaces affect the release, immobilization and bioavailability of Se in nature. Herein, the effects of three environmentally relevant LMWOAs (i.e., oxalic (Oxa), succinic (Suc)and citric (Cit)acids)on Se(IV)adsorption to goethite under oxic conditions were investigated using batch experiments, speciation fractionation, and ATR-FTIR and XPS analyses. The LMWOAs exhibited a competitive-synergistic coupling effect on Se(IV)adsorption to goethite, which inhibited the adsorption rate of Se(IV)by 14.1, 13.3 and 8.0 times. However, immobilization of Se(IV)was simultaneously enhanced by 39.1%, 34.6% and 14.1% in the following order Oxa > Suc > Cit. The results obtained by fractionation of the adsorbed Se(IV)revealed that the enhancement was due to surface binding as well as speciation transformation from ligand-exchangeable Se(IV)into residual fractions, which increased by approximately 18% in the presence of the LMWOAs. The dissolution of goethite significantly improved due to the LMWOAs and decreased to different degrees as the concentration of Se(IV)increased. The monodentate mononuclear complexes (58.2%)and Lewis base sites bonded Se (41.8%)were the predominant surface species of Se(IV)in goethite-Se(IV)system. The ATR-FTIR and high-resolution XPS analyses demonstrated that the formation of ≡FeO(SeO)O-CO surface complexes (22.8–27.0%)occurred in the presence of LMWOAs, which could be closely correlated with the interface-mediated reduction of Se(IV). In addition, the predominant mechanism for the formation of residual Se is LMWOA specific, in which ferric selenite-like precipitation was dominant for Suc (10.6%)and Cit (11.6%)and reduction was dominant for Oxa (17.5%). Overall, LMWOAs play an important role in Se(IV)immobilization and speciation transformation and may facilitate understanding the Se bioavailability in rhizosphere soils under oxic conditions.
The Potential Impact of Underwater Exhausted CO2 from Innovative Ships on Invertebrate Communities
Wei, Yuzhu ; Plath, Lara ; Penning, Anne ; Linden, Maartje van der; Murk, Albertinka J. ; Foekema, Edwin M. - \ 2019
International Journal Environmental Research 13 (2019)4. - ISSN 1735-6865 - p. 669 - 678.
Underwater exhaust - Periphyton - Plankton - Benthos - Mesocosm - ocean acidification
Liquefied natural gas (LNG) powered ships equipped with an underwater exhaust system to reduce the ship’s water resistance could form a future generation of energy-efficient ships. The potential consequences of the underwater exhaust gas to the local ecosystems are still unknown. Especially, the CO2 levels may locally exceed estimated future global levels. The present study exposes marine communities to a wide range of CO2 dosages, resulting in pH 8.6–5.8 that was remained for 49 days. We found that the zooplankton and benthic community were adversely affected by high CO2 exposure levels. In detail, (1) between pH 6.6 and 7.1 polychaete worms became the dominating group of the benthic community and their larvae dominated the zooplankton group. (2) Due to the reduced grazing pressure and the flux of nutrients from decaying organic material planktonic microalgae (phytoplankton) stared blooming at the highest exposure level. The periphyton (fouling microalgae) community was not able to take advantage under these conditions. (3) Marine snails’ (periwinkle) shell damage and high mortality were observed at pH < 6.6. However, the growth of the surviving periwinkles was not directly related to pH, but was positively correlated with the availability of periphyton and negatively correlated with the polychaete worm density that most likely also used the periphyton as food source. Our result indicates that the impact of underwater exhaust gasses depends on various factors including local biological and abiotic conditions, which will be included in future research.
Deciphering complex metabolite mixtures by unsupervised and supervised substructure discovery and semi-automated annotation from MS/MS spectra
Rogers, Simon ; Wei Ong, Cher ; Wandy, Joe ; Ernst, Madeleine ; Ridder, Lars ; Hooft, Justin J.J. Van Der - \ 2019
Faraday Discussions 218 (2019). - ISSN 1359-6640 - p. 284 - 302.
Complex metabolite mixtures are challenging to unravel. Mass spectrometry (MS) is a widely used and sensitive technique to obtain structural information on complex mixtures. However, just knowing the molecular masses of the mixture’s constituents is almost always insufficient for confident assignment of the associated chemical structures. Structural information can be augmented through MS fragmentation experiments whereby detected metabolites are fragmented giving rise to MS/MS spectra. However, how can we maximize the structural information we gain from fragmentation spectra? We recently proposed a substructure-based strategy to enhance metabolite annotation for complex mixtures by considering metabolites as the sum of (bio)chemically relevant moieties that we can detect through mass spectrometry fragmentation approaches. Our MS2LDA tool allows us to discover - unsupervised - groups of mass fragments and/or neutral losses termed Mass2Motifs that often correspond to substructures. After manual annotation, these Mass2Motifs can be used in subsequent MS2LDA analyses of new datasets, thereby providing structural annotations for many molecules that are not present in spectral databases. Here, we describe how additional strategies, taking advantage of i) combinatorial in-silico matching of experimental mass features to substructures of candidate molecules, and ii) automated machine learning classification of molecules, can facilitate semi-automated annotation of substructures. We show how our approach accelerates the Mass2Motif annotation process and therefore broadens the chemical space spanned by characterized motifs. Our machine learning model used to classify fragmentation spectra learns the relationships between fragment spectra and chemical features. Classification prediction on these features can be aggregated for all molecules that contribute to a particular Mass2Motif and guide Mass2Motif annotations. To make annotated Mass2Motifs available to the community, we also present motifDB: an open database of Mass2Motifs that can be browsed and accessed programmatically through an API. MotifDB is integrated within, allowing users to efficiently search for characterized motifs in their own experiments. We expect that with an increasing number of Mass2Motif annotations available through a growing database we can more quickly gain insight in the constituents of complex mixtures. That will allow prioritization towards novel or unexpected chemistries and faster recognition of known biochemical building blocks.
Rising rural body-mass index is the main driver of the global obesity epidemic in adults
Bixby, Honor ; Bentham, James ; Zhou, Bin ; Cesare, Mariachiara Di; Paciorek, Christopher J. ; Bennett, James E. ; Taddei, Cristina ; Stevens, Gretchen A. ; Rodriguez-Martinez, Andrea ; Carrillo-Larco, Rodrigo M. ; Khang, Young Ho ; Sorić, Maroje ; Gregg, Edward W. ; Miranda, J.J. ; Bhutta, Zulfiqar A. ; Savin, Stefan ; Sophiea, Marisa K. ; Iurilli, Maria L.C. ; Solomon, Bethlehem D. ; Cowan, Melanie J. ; Riley, Leanne M. ; Danaei, Goodarz ; Bovet, Pascal ; Chirita-Emandi, Adela ; Hambleton, Ian R. ; Hayes, Alison J. ; Ikeda, Nayu ; Kengne, Andre P. ; Laxmaiah, Avula ; Li, Yanping ; McGarvey, Stephen T. ; Mostafa, Aya ; Neovius, Martin ; Starc, Gregor ; Zainuddin, Ahmad A. ; Abarca-Gómez, Leandra ; Abdeen, Ziad A. ; Abdrakhmanova, Shynar ; Abdul Ghaffar, Suhaila ; Abdul Hamid, Zargar ; Abubakar Garba, Jamila ; Ferrieres, Jean ; He, Yuna ; Jacobs, Jeremy M. ; Kromhout, Daan ; Ma, Guansheng ; Visser, Marjolein ; Wang, Qian ; Wang, Ya Xing ; Wang, Ying Wei - \ 2019
Nature 569 (2019)7755. - ISSN 0028-0836 - p. 260 - 264.

Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities 1,2 . This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity 3–6 . Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55% of the global rise in mean BMI from 1985 to 2017—and more than 80% in some low- and middle-income regions—was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing—and in some countries reversal—of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories.

Pyrethric acid of natural pyrethrin insecticide: complete pathway elucidation and reconstitution in Nicotiana benthamiana
Xu, H. ; Li, Wei ; Schilmiller, Anthony L. ; Eekelen, H.D.L.M. van; Vos, C.H. de; Jongsma, M.A. ; Pichersky, E. - \ 2019
New Phytologist 223 (2019)2. - ISSN 0028-646X - p. 751 - 765.
In the natural pesticides known as pyrethrins, which are esters produced in flowers of Tanacetum cinerariifolium (Asteraceae), the monoterpenoid acyl moiety is pyrethric acid or chrysanthemic acid.
We show here that pyrethric acid is produced from chrysanthemol in six steps catalyzed by four enzymes, the first five steps occurring in the trichomes covering the ovaries and the last one occurring inside the ovary tissues.
Three steps involve the successive oxidation of carbon 10 (C10) to a carboxylic group by TcCHH, a cytochrome P450 oxidoreductase. Two other steps involve the successive oxidation of the hydroxylated carbon 1 to give a carboxylic group by TcADH2 and TcALDH1, the same enzymes that catalyze these reactions in the formation of chrysanthemic acid. The ultimate result of the actions of these three enzymes is the formation of 10‐carboxychrysanthemic acid in the trichomes. Finally, the carboxyl group at C10 is methylated by TcCCMT, a member of the SABATH methyltransferase family, to give pyrethric acid. This reaction occurs mostly in the ovaries.
Expression in N. benthamiana plants of all four genes encoding aforementioned enzymes, together with TcCDS, a gene that encodes an enzyme that catalyzes the formation of chrysanthemol, led to the production of pyrethric acid.
Airborne host–plant manipulation by whiteflies via an inducible blend of plant volatiles
Zhang, Peng Jun ; Wei, Jia Ning ; Zhao, Chan ; Zhang, Ya Fen ; Li, Chuan You ; Liu, Shu Sheng ; Dicke, Marcel ; Yu, Xiao Ping ; Turlings, Ted C.J. - \ 2019
Proceedings of the National Academy of Sciences of the United States of America 116 (2019)15. - ISSN 0027-8424 - p. 7387 - 7396.
Herbivore-induced plant volatiles - Jasmonic acid - Salicylic acid - Tomato - Whiteflies

The whitefly Bemisia tabaci is one of the world’s most important invasive crop pests, possibly because it manipulates plant defense signaling. Upon infestation by whiteflies, plants mobilize salicylic acid (SA)-dependent defenses, which mainly target pathogens. In contrast, jasmonic acid (JA)-dependent defenses are gradually suppressed in whitefly-infested plants. The down-regulation of JA defenses make plants more susceptible to insects, including whiteflies. Here, we report that this host–plant manipulation extends to neighboring plants via airborne signals. Plants respond to insect attack with the release of a blend of inducible volatiles. Perception of these volatiles by neighboring plants usually primes them to prepare for an imminent attack. Here, however, we show that whitefly-induced tomato plant volatiles prime SA-dependent defenses and suppress JA-dependent defenses, thus rendering neighboring tomato plants more susceptible to whiteflies. Experiments with volatiles from caterpillar-damaged and pathogen-infected plants, as well as with synthetic volatiles, confirm that whiteflies modify the quality of neighboring plants for their offspring via whitefly-inducible plant volatiles.

A second HD mating type sublocus of Flammulina velutipes is at least di-allelic and active : New primers for identification of HD - A and HD-b subloci
Wang, Wei ; Mukhtar, Irum ; Chou, Tiansheng ; Jiang, Siyuan ; Liu, Xinrui ; Peer, Arend F. Van; Xie, Baogui - \ 2019
PeerJ 2019 (2019)2. - ISSN 2167-8359
Di-allelic - Flammulina velutipes - HD subloci - Homeodomain - Mating pathway - Primers

Background: Sexual development in Flammulina velutipes is controlled by two different mating type loci (HD and PR). The HD locus contains homeodomain (Hd) genes on two separate HD subloci: HD-a and HD-b. While the functionality of the HD-b sublocus has been largely confirmed, the status and content of the HD-a sublocus has remained unclear. Methods: To examine the function of the HD-a sublocus, genome sequences of a series of F. velutipes strains were analyzed and tested through series of amplification by specific primer sets. Furthermore, activity of di-allelic HD-a locus was confirmed by crossing strains with different combinations of HD-a and HD-b subloci. Results: Sublocus HD-b contained a large variety of fixed Hd1/Hd2 gene pairs, while the HD-a sublocus either contained a conserved Hd2 gene or, a newly discovered Hd1 gene that was also conserved. Identification of whole HD loci, that is, the contents of HD-a and HD-b subloci in a strain, revealed that strains with similar HD-b subloci could still form normal dikaryons if the two genes at the HD-a sublocus differed. At least di-allelic HD-a sublocus, is thus indicated to be actively involved in mating type compatibility. Conclusions: HD-a sublocus is active and di-allelic. Using the new information on the HD subloci, primers sets were developed that specifically amplify HD-a or HD-b subloci in the majority of F. velutipes strains. In this way, unknown HD mating types of F. velutipes can now be quickly identified, and HD mating type compatibility conferred by HD-a or HD-b can be confirmed by PCR.

Genetic variant predictors of gene expression provide new insight into risk of colorectal cancer
Bien, Stephanie A. ; Su, Yu-Ru ; Conti, David V. ; Harrison, Tabitha A. ; Qu, Conghui ; Guo, Xingyi ; Lu, Yingchang ; Albanes, Demetrius ; Auer, Paul L. ; Banbury, Barbara L. ; Berndt, Sonja I. ; Bézieau, Stéphane ; Brenner, Hermann ; Buchanan, Daniel D. ; Caan, Bette J. ; Campbell, Peter T. ; Carlson, Christopher S. ; Chan, Andrew T. ; Chang-Claude, Jenny ; Chen, Sai ; Connolly, Charles M. ; Easton, Douglas F. ; Feskens, Edith J.M. ; Gallinger, Steven ; Giles, Graham G. ; Gunter, Marc J. ; Hampe, Jochen ; Huyghe, Jeroen R. ; Hoffmeister, Michael ; Hudson, Thomas J. ; Jacobs, Eric J. ; Jenkins, Mark A. ; Kampman, Ellen ; Kang, Hyun Min ; Kühn, Tilman ; Küry, Sébastien ; Lejbkowicz, Flavio ; Marchand, Loic Le; Milne, Roger L. ; Li, Christopher I. ; Lindblom, Annika ; Lindor, Noralane M. ; Martín, Vicente ; McNeil, Caroline E. ; Melas, Marilena ; Moreno, Victor ; Newcomb, Polly A. ; Offit, Kenneth ; Pharaoh, Paul D.P. ; Potter, John D. ; Qu, Chenxu ; Riboli, Elio ; Rennert, Gad ; Sala, Núria ; Schafmayer, Clemens ; Scacheri, Peter C. ; Schmit, Stephanie L. ; Severi, Gianluca ; Slattery, Martha L. ; Smith, Joshua D. ; Trichopoulou, Antonia ; Tumino, Rosario ; Ulrich, Cornelia M. ; Duijnhoven, Fränzel J.B. van; Guelpen, Bethany Van; Weinstein, Stephanie J. ; White, Emily ; Wolk, Alicja ; Woods, Michael O. ; Wu, Anna H. ; Abecasis, Goncalo R. ; Casey, Graham ; Nickerson, Deborah A. ; Gruber, Stephen B. ; Hsu, Li ; Zheng, Wei ; Peters, Ulrike - \ 2019
Human Genetics 138 (2019)4. - ISSN 0340-6717 - p. 307 - 326.
Genome-wide association studies have reported 56 independently associated colorectal cancer (CRC) risk variants, most of which are non-coding and believed to exert their effects by modulating gene expression. The computational method PrediXcan uses cis-regulatory variant predictors to impute expression and perform gene-level association tests in GWAS without directly measured transcriptomes. In this study, we used reference datasets from colon (n = 169) and whole blood (n = 922) transcriptomes to test CRC association with genetically determined expression levels in a genome-wide analysis of 12,186 cases and 14,718 controls. Three novel associations were discovered from colon transverse models at FDR ≤ 0.2 and further evaluated in an independent replication including 32,825 cases and 39,933 controls. After adjusting for multiple comparisons, we found statistically significant associations using colon transcriptome models with TRIM4 (discovery P = 2.2 × 10− 4, replication P = 0.01), and PYGL (discovery P = 2.3 × 10− 4, replication P = 6.7 × 10− 4). Interestingly, both genes encode proteins that influence redox homeostasis and are related to cellular metabolic reprogramming in tumors, implicating a novel CRC pathway linked to cell growth and proliferation. Defining CRC risk regions as one megabase up- and downstream of one of the 56 independent risk variants, we defined 44 non-overlapping CRC-risk regions. Among these risk regions, we identified genes associated with CRC (P < 0.05) in 34/44 CRC-risk regions. Importantly, CRC association was found for two genes in the previously reported 2q25 locus, CXCR1 and CXCR2, which are potential cancer therapeutic targets. These findings provide strong candidate genes to prioritize for subsequent laboratory follow-up of GWAS loci. This study is the first to implement PrediXcan in a large colorectal cancer study and findings highlight the utility of integrating transcriptome data in GWAS for discovery of, and biological insight into, risk loci.
A Low-Power MEMS IDE Capacitor with Integrated Microhotplate : Application as Methanol Sensor using a Metal-Organic Framework Coating as Affinity Layer
Venkatesh, Manjunath R. ; Sachdeva, Sumit ; Mansouri, Brahim El; Wei, Jia ; Bossche, Andre ; Bosma, Duco ; Smet, Louis C.P.M. de; Sudhölter, Ernst J.R. ; Zhang, Guo Qi - \ 2019
Sensors 19 (2019)4. - ISSN 1424-8220
Capacitor interdigitated electrodes - MEMS microhotplate - ZIF-8

Capacitors made of interdigitated electrodes (IDEs) as a transducer platform for the sensing of volatile organic compounds (VOCs) have advantages due to their lower power operation and fabrication using standard micro-fabrication techniques. Integrating a micro-electromechanical system (MEMS), such as a microhotplate with IDE capacitor, further allows study of the temperature- dependent sensing response of VOCs. In this paper, the design, fabrication, and characterization of a low-power MEMS microhotplate with IDE capacitor to study the temperature-dependent sensing response to methanol using Zeolitic imidazolate framework (ZIF-8), a class of metal-organic framework (MOF), is presented. A Titanium nitride (TiN) microhotplate with aluminum IDEs suspended on a silicon nitride membrane is fabricated and characterized. The power consumption of the ZIF-8 MOF-coated device at an operating temperature of 50 ∘ C is 4.5 mW and at 200 ∘ C it is 26 mW. A calibration methodology for the effects of temperature of the isolation layer between the microhotplate electrodes and the capacitor IDEs is developed. The device coated with ZIF-8 MOF shows a response to methanol in the concentration range of 500 ppm to 7000 ppm. The detection limit of the sensor for methanol vapor at 20 ∘ C is 100 ppm. In situ study of sensing properties of ZIF-8 MOF to methanol in the temperature range from 20 ∘ C to 50 ∘ C using the integrated microhotplate and IDE capacitor is presented. The kinetics of temperature-dependent adsorption and desorption of methanol by ZIF-8 MOF are fitted with double-exponential models. With the increase in temperature from 20 ∘ C to 50 ∘ C, the response time for sensing of methanol vapor concentration of 5000 ppm decreases by 28%, whereas the recovery time decreases by 70%.

A model to examine farm household trade-offs and synergies with an application to smallholders in Vietnam
Ditzler, Lenora ; Komarek, Adam M. ; Chiang, Tsai Wei ; Alvarez, Stéphanie ; Chatterjee, Shantonu Abe ; Timler, Carl ; Raneri, Jessica E. ; Carmona, Natalia Estrada ; Kennedy, Gina ; Groot, Jeroen C.J. - \ 2019
Agricultural Systems 173 (2019). - ISSN 0308-521X - p. 49 - 63.
FarmDESIGN model - Farmer livelihoods - Labor - Multi-objective optimization - Nutrition - Soil organic matter

Farm models have the potential to describe farming systems and livelihoods, identify trade-offs and synergies, and provide ex-ante assessments of agricultural technologies and policies. We developed three new modules related to budget, labor, and human nutrition for the bio-economic whole-farm model ‘FarmDESIGN’. The expanded model positions the farming enterprise within the farm household. We illustrate the model's new capabilities for farm households in two villages in Northwest Vietnam, where we conducted multi-objective optimization to identify options for improving the farm households' current performance on key sustainability and livelihood indicators. Modeling results suggest trade-offs between environmental, economic, and social objectives are common, although not universal. The new modules increase the scope for modeling flows of resources (namely cash, labor, and food) between the farm enterprise and the farm household, as well as beyond the farm gate. This allows conducting modeling explorations, optimization routines, and scenario analyses in farming systems research.

Comparing Arabidopsis receptor kinase and receptor protein-mediated immune signaling reveals BIK1-dependent differences
Wan, Wei Lin ; Zhang, Lisha ; Pruitt, Rory ; Zaidem, Maricris ; Brugman, Rik ; Ma, Xiyu ; Krol, Elzbieta ; Perraki, Artemis ; Kilian, Joachim ; Grossmann, Guido ; Stahl, Mark ; Shan, Libo ; Zipfel, Cyril ; Kan, Jan A.L. van; Hedrich, Rainer ; Weigel, Detlef ; Gust, Andrea A. ; Nürnberger, Thorsten - \ 2019
New Phytologist 221 (2019)4. - ISSN 0028-646X - p. 2080 - 2095.
Arabidopsis - immune receptor - immune signaling comparison - plant immunity - receptor kinase - receptor protein

Pattern recognition receptors (PRRs) sense microbial patterns and activate innate immunity against attempted microbial invasions. The leucine-rich repeat receptor kinases (LRR-RK) FLS2 and EFR, and the LRR receptor protein (LRR-RP) receptors RLP23 and RLP42, respectively, represent prototypical members of these two prominent and closely related PRR families. We conducted a survey of Arabidopsis thaliana immune signaling mediated by these receptors to address the question of commonalities and differences between LRR-RK and LRR-RP signaling. Quantitative differences in timing and amplitude were observed for several early immune responses, with RP-mediated responses typically being slower and more prolonged than those mediated by RKs. Activation of RLP23, but not FLS2, induced the production of camalexin. Transcriptomic analysis revealed that RLP23-regulated genes represent only a fraction of those genes differentially expressed upon FLS2 activation. Several positive and negative regulators of FLS2-signaling play similar roles in RLP23 signaling. Intriguingly, the cytoplasmic receptor kinase BIK1, a positive regulator of RK signaling, acts as a negative regulator of RP-type immune receptors in a manner dependent on BIK1 kinase activity. Our study unveiled unexpected differences in two closely related receptor systems and reports a new negative role of BIK1 in plant immunity.

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