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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Effect of different microphysics scheme on WRF model : A simulation of hail event study case in Surabaya, Indonesia
Sari, Fitria P. ; Baskoro, Ary Pulung ; Hakim, Oky Sukma - \ 2018
In: International Symposium on Earth Hazard and Disaster Mitigation, ISEDM 2017. - American Institute of Physics Inc. - ISBN 9780735417038

In the present study, the Weather Research and Forecasting (WRF) Model was employed to simulate hail event over Surabaya on 8 March 2017 in term of evaluating sensitivity to four microphysical schemes (WSM3, WSM6, Thompson, and Morrison). The analyzed weather variables were surface parameters (e.g. temperature, air pressure, u-wind component), reflectivity, surface wind field, and hydrometeor particles (e.g. cloud, rain, ice, and graupel) which is compared to observation (e.g. AWS and DWR product). Two main analysis were performed: point-to-point and spatial (e.g. horizontal, vertical, and temporal) analysis. The result was, among surface variables, u-wind component acted significantly different from observation due to boundary condition bias and strong synoptic-scale forcing. This error led model to produce misplaced the storm cloud but appropriate in time. The MORRISON-2 scheme could simulate size and lifetime of convective cloud close to radar observation, but THOMPSON is more able to generate cloud properties in proper condition when hail event is possible to occur. The adding number of concentration only for rain species and let the graupel intercept parameter depend upon its mixing ratio lead this scheme is more robust to simulate mix-phase cloud development. Therefore THOMPSON scheme is more suitable to reproduce cloud convective which more dominated by rain species as a typical of tropical cloud.

Coral reefs in the Anthropocene
Hughes, Terry P. ; Barnes, Michele L. ; Bellwood, David R. ; Cinner, Joshua E. ; Cumming, Graeme S. ; Jackson, Jeremy B.C. ; Kleypas, Joanie ; De Leemput, Ingrid A. Van; Lough, Janice M. ; Morrison, Tiffany H. ; Palumbi, Stephen R. ; Nes, Egbert H. Van; Scheffer, Marten - \ 2017
Nature 546 (2017)7656. - ISSN 0028-0836 - p. 82 - 90.
Coral reefs support immense biodiversity and provide important ecosystem services to many millions of people. Yet reefs are degrading rapidly in response to numerous anthropogenic drivers. In the coming centuries, reefs will run the gauntlet of climate change, and rising temperatures will transform them into new configurations, unlike anything observed previously by humans. Returning reefs to past configurations is no longer an option. Instead, the global challenge is to steer reefs through the Anthropocene era in a way that maintains their biological functions. Successful navigation of this transition will require radical changes in the science, management and governance of coral reefs.
Denial of long-term issues with agriculture on tropical peatlands will have devastating consequences
Wijedasa, Lahiru S. ; Jauhiainen, Jyrki ; Könönen, Mari ; Lampela, Maija ; Vasander, Harri ; Leblanc, Marie-Claire ; Evers, Stephanie ; Smith, Thomas E.L. ; Yule, Catherine M. ; Varkkey, Helena ; Lupascu, Massimo ; Parish, Faizal ; Singleton, Ian ; Clements, Gopalasamy R. ; Aziz, Sheema Abdul ; Harrison, Mark E. ; Cheyne, Susan ; Anshari, Gusti Z. ; Meijaard, Erik ; Goldstein, Jenny E. ; Waldron, Susan ; Hergoualc'h, Kristell ; Dommain, Rene ; Frolking, Steve ; Evans, Christopher D. ; Posa, Mary Rose C. ; Glaser, Paul H. ; Suryadiputra, Nyoman ; Lubis, Reza ; Santika, Truly ; Padfield, Rory ; Kurnianto, Sofyan ; Hadisiswoyo, Panut ; Lim, Teck Wyn ; Page, Susan E. ; Gauci, Vincent ; Meer, Peter J. Van Der; Buckland, Helen ; Garnier, Fabien ; Samuel, Marshall K. ; Choo, Liza Nuriati Lim Kim ; O'reilly, Patrick ; Warren, Matthew ; Suksuwan, Surin ; Sumarga, Elham ; Jain, Anuj ; Laurance, William F. ; Couwenberg, John ; Joosten, Hans ; Vernimmen, Ronald ; Hooijer, Aljosja ; Malins, Chris ; Cochrane, Mark A. ; Perumal, Balu ; Siegert, Florian ; Peh, Kelvin S.H. ; Comeau, Louis-Pierre ; Verchot, Louis ; Harvey, Charles F. ; Cobb, Alex ; Jaafar, Zeehan ; Wösten, Henk ; Manuri, Solichin ; Müller, Moritz ; Giesen, Wim ; Phelps, Jacob ; Yong, Ding Li ; Silvius, Marcel ; Wedeux, Béatrice M.M. ; Hoyt, Alison ; Osaki, Mitsuru ; Hirano, Takashi ; Takahashi, Hidenori ; Kohyama, Takashi S. ; Haraguchi, Akira ; Nugroho, Nunung P. ; Coomes, David A. ; Quoi, Le Phat ; Dohong, Alue ; Gunawan, Haris ; Gaveau, David L.A. ; Langner, Andreas ; Lim, Felix K.S. ; Edwards, David P. ; Giam, Xingli ; Werf, Guido Van Der; Carmenta, Rachel ; Verwer, Caspar C. ; Gibson, Luke ; Gandois, Laure ; Graham, Laura Linda Bozena ; Regalino, Jhanson ; Wich, Serge A. ; Rieley, Jack ; Kettridge, Nicholas ; Brown, Chloe ; Pirard, Romain ; Moore, Sam ; Capilla, B.R. ; Ballhorn, Uwe ; Ho, Hua Chew ; Hoscilo, Agata ; Lohberger, Sandra ; Evans, Theodore A. ; Yulianti, Nina ; Blackham, Grace ; Onrizal, O. ; Husson, Simon ; Murdiyarso, Daniel ; Pangala, Sunita ; Cole, Lydia E.S. ; Tacconi, Luca ; Segah, Hendrik ; Tonoto, Prayoto ; Lee, Janice S.H. ; Schmilewski, Gerald ; Wulffraat, Stephan ; Putra, Erianto Indra ; Cattau, Megan E. ; Clymo, R.S. ; Morrison, Ross ; Mujahid, Aazani ; Miettinen, Jukka ; Liew, Soo Chin ; Valpola, Samu ; Wilson, David ; Arcy, Laura D'; Gerding, Michiel ; Sundari, Siti ; Thornton, Sara A. ; Kalisz, Barbara ; Chapman, Stephen J. ; Su, Ahmad Suhaizi Mat ; Basuki, Imam ; Itoh, Masayuki ; Traeholt, Carl ; Sloan, Sean ; Sayok, Alexander K. ; Andersen, Roxane - \ 2017
Global Change Biology 23 (2017)3. - ISSN 1354-1013 - p. 977 - 982.
The first International Peat Congress (IPC) held in the tropics – in Kuching (Malaysia) – brought together over 1000 international peatland scientists and industrial partners from across the world (“International Peat Congress with over 1000 participants!,” 2016). The congress covered all aspects of peatland ecosystems and their management, with a strong focus on the environmental, societal and economic challenges associated with contemporary large-scale agricultural conversion of tropical peat.
Engineers at the Patient’s Bedside: : The Case of Silence in Inter-institutional Educational Innovation
Verouden, Nick ; Sanden, M.C.A. van der; Aarts, M.N.C. - \ 2016
In: The Silences of Science / Mellor, Felicity, Webster, Stephen, London : Routledge - ISBN 9781472459978 - p. 89 - 112.
Innovation in science and technology is increasingly linked with interdisciplinarity. Encouraging this trend depends in part on cutting-edge educational programmes that revise, reinvent and redesign curricula as interdisciplinary vehicles, establishing and re-establishing relations between traditional fields and areas of expertise (Stone et al., 1999; Casey, 1994). Such programmes are valuable because they can overcome ‘silo’ mentalities and equip prospective students with the skills and knowledge necessary for understanding and solving complex societal problems (Stone et al.,1999; McFadden et al., 2010). Although these programmes are very promising, their development and

implementation also brings challenges. The literature on curriculum development shows that many programmes have struggled to achieve true integration (McFadden et al., 2010; Stone et al., 1999). Dam-Mieras et al. (2008), in their study of an international master’s programme in sustainable development and management developed collaboratively by nine universities, observed that universities have their own experts and own programmes and that the ‘not invented here’ argument influences how details about new programme are discussed. Focussing on innovative online instruction courses, Xu and Morris (2007) found that the absence of group cohesiveness between faculty and project coordinators can hinder the collaborative course development process and affect the quality of the end product. Stone et al. (1999) emphasize that faculty members and administrators work at cross-purposes and view each other’s initiatives with suspicion. Given the importance that scientists, academic institutions and policy makers ascribe to innovation, along with their assumption that such innovation is a sure result of interdisciplinarity, it is essential to gain a better understanding of how curriculum development in academic education actually works. For this chapter, we consider how processes of connecting and inter-

relating could add to our understanding of the problems and dilemmas that arise in developing and implementing such programmes. Scholars of innovation, in science and technology and beyond, have explained that innovation is not some abstract algorithm: it relies on interaction and collaboration between

multiple actors with different expertises, visions, priorities and investment (Van Bommel et al., 2011; Leeuwis and Aarts, 2011; Akrich et al., 2002; Fonseca, 2002). This process of interacting is very difficult, however, and creates many tensions. This is revealed by studies that show the lurking problems of connecting previously unconnected people around new ideas and technologies. These studies show how innovation processes become defined by competition for scarce resources, protracted negotiations over priorities and interests, and dynamics of inclusion and exclusion (Leeuwis andAarts, 2011; Pretty, 1995; Van Bommel et al., 2011). Fonseca (2002) hence explains that innovation always creates a paradoxical situation, in which organizations, in their search to accelerate change and adapt to and find solutions for external challenges and demands, unavoidably create new and unpredictable interactional patterns. Given that interacting is a complicated matter in innovation processes, a

key question within the management of innovation literature is how we can account for the way relevant actors connect, or fail to connect (Akrich et al., 2002). In this respect, verbal communication is often cited as an essential mechanism for effectively connecting important actors and social groups around innovative ideas, products, or technologies (Van Bommel et al., 2011). In turn, the markers of effective verbal communication as a frame for innovation are seen to be openness, dialogue, and the ability to cooperate and be reflective on one’s thoughts and actions (Stilgoe et al., 2013). Thorp and Goldstein (2010), writing about university innovation, describe conversations as the fertile ground from which innovation grows and urge us to make time and space for those conversations. Dialogue and openness are seen as indicators of the quality of interaction, and process transparency as a decisive component of academic innovation. By being open or transparent in discussing issues and problems, actors build confidence that negotiation is ‘real’ and not a cover-up for private backroom deals (de Bruijn and ten Heuvelhof, 2008). Although there is a wealth of research on communication for innovation,

most scholarly work focuses on what is exchanged verbally, on how actors collate all the relevant evidence, put it on the table and discuss it openly. As of yet, silence is absent from these studies of communication for innovation. Building on recent organizational and strategy scholarship, in which silence is approached as an intricate concept with powerful functions and meanings in social interaction (Van Assche and Costaglioli, 2012; Carter et al., 2008; Henriksen and Dayton, 2006; Panteli and Fineman, 2005; Tucker and Edmondson, 2003; Jaworski, 2005; Morrison and Milliken, 2000), we suggest that silence merits much more attention in analyses of academic innovation. This chapter therefore explores the role of moments of silence during interactions within networks developing and implementing educational innovation. The structure of this chapter is as follows. We start by looking at the litera-

ture on dynamic innovation networks and communication and complement these insights with scholarship on silence within organization studies. After briefly introducing our approach, we present the findings of a study of an inter-institutional and interdisciplinary joint bachelor’s programme that was

implemented at the interface of health and technology. The purpose of the study was to better understand the significance of moments of silence in developing and implementing this programme. We end with the implications of our findings for steering in the context of interdisciplinary innovation.
PLASTOX: Direct and indirect ecotoxicological impacts of microplastics on marine organisms
Booth, Andy ; Sakaguchi-Soder, Kaori ; Sobral, Paula ; Airoldi, Laura ; Sempere, Richard ; Franeker, J.A. van; Magnusson, Kerstin ; Doyle, Thomas ; Morrison, Liam ; Salaverria, Iurgi ; Colen, Carl van; Herzke, Dorte ; Orbea, Amaia ; Gabrielsen, Geir Wing ; Nies, Hartmut ; Galloway, Tamara ; Oyen, Albert Van - \ 2016
Revisiting Morrison and Osterle 1965 : The efficiency of membrane-based electrokinetic energy conversion
Catalano, J. ; Hamelers, H.V.M. ; Bentien, A. ; Biesheuvel, Maarten - \ 2016
Journal of Physics-Condensed Matter 28 (2016)32. - ISSN 0953-8984
charged nanopore - desalination - electrokinetic energy conversion

We revisit Morrison and Osterle (1965) who derived a phenomenological expression for the 'figure-of-merit' βEK of the electrokinetic energy conversion (EKEC) of a pressure difference into electric energy (and vice versa) using charged nanotubes, nanopores or ion-exchange membranes. We show the equivalence with Morrison and Osterle of a novel expression of βEK derived by Bentien et al (2013). We analyze two physical models for ionic and solvent flow which directly relate βEK to nanopore characteristics such as pore size and wall charge density. For the uniform potential model, we derive an analytical expression as a function of pore size, viscosity, ion diffusion coefficients and membrane charge density, and compare results with the full space-charge model by Osterle and co-workers as a function of pore size and ion diffusion coefficient. We present a novel expression for βEK for salt solutions with ions with unequal diffusion coefficients (mobilities) and show that to increase βEK the counterion mobility must be low and the coion mobility high.

Replacement of dietary saturated fat by PUFA-rich pumpkin seed oil attenuates non-alcoholic fatty liver disease and atherosclerosis development, with additional health effects of virgin over refined oil
Morrison, M.C. ; Mulder, Petra ; Stavro, P.M. ; Suárez, Manuel ; Arola-Arnal, Anna ; Duyvenvoorde, Wim Van; Kooistra, Teake ; Wielinga, P.Y. ; Kleemann, Robert - \ 2015
PLoS One 10 (2015)9. - ISSN 1932-6203 - 19 p.

Background and Aims: As dietary saturated fatty acids are associated with metabolic and cardiovascular disease, a potentially interesting strategy to reduce disease risk is modification of the quality of fat consumed. Vegetable oils represent an attractive target for intervention, as they largely determine the intake of dietary fats. Furthermore, besides potential health effects conferred by the type of fatty acids in a vegetable oil, other minor components (e.g. phytochemicals) may also have health benefits. Here, we investigated the potential long-term health effects of isocaloric substitution of dietary fat (i.e. partial replacement of saturated by unsaturated fats), as well as putative additional effects of phytochemicals present in unrefined (virgin) oil on development of non-alcoholic fatty liver disease (NAFLD) and associated atherosclerosis. For this, we used pumpkin seed oil, because it is high in unsaturated fatty acids and a rich source of phytochemicals. Methods: ApoE∗3Leiden mice were fed a Western-type diet (CON) containing cocoa butter (15% w/ w) and cholesterol (1% w/w) for 20 weeks to induce risk factors and disease endpoints. In separate groups, cocoa butter was replaced by refined (REF) or virgin (VIR) pumpkin seed oil (comparable in fatty acid composition, but different in phytochemical content). Results: Both oils improved dyslipidaemia, with decreased (V)LDL-cholesterol and triglyceride levels in comparison with CON, and additional cholesterol-lowering effects of VIR over REF. While REF did not affect plasma inflammatory markers, VIR reduced circulating serum amyloid A and soluble vascular adhesion molecule-1. NAFLD and atherosclerosis development was modestly reduced in REF, and VIR strongly decreased liver steatosis and inflammation as well as atherosclerotic lesion area and severity. Conclusions: Overall, we show that an isocaloric switch from a diet rich in saturated fat to a diet rich in unsaturated fat can attenuate NAFLD and atherosclerosis development. Phytochemicalrich virgin pumpkin seed oil exerts additional anti-inflammatory effects resulting in more pronounced health effects.

Role of macrophage migration inhibitory factor in obesity, insulin resistance, type 2 diabetes, and associated hepatic co-morbidities : A comprehensive review of human and rodent studies
Morrison, M.C. ; Kleemann, Robert - \ 2015
Frontiers in Immunology 6 (2015). - ISSN 1664-3224
Adipose tissue - Insulin resistance - MIF - Non-alcoholic fatty liver disease - Obesity - Type 2 diabetes

Obesity is associated with a chronic low-grade inflammatory state that drives the -development of obesity-related co-morbidities such as insulin resistance/type 2 diabetes, non-alcoholic fatty liver disease (NAFLD), and cardiovascular disease. This metabolic inflammation is thought to originate in the adipose tissue, which becomes inflamed and insulin resistant when it is no longer able to expand in response to excess caloric and nutrient intake. The production of inflammatory mediators by dysfunctional adipose tissue is thought to drive the development of more complex forms of disease such as type 2 diabetes and NAFLD. An important factor that may contribute to metabolic inflammation is the cytokine macrophage migration inhibitory factor (MIF). Increasing evidence suggests that MIF is released by adipose tissue in obesity and that it is also involved in metabolic and inflammatory processes that underlie the development of obesity-related pathologies. This review provides a comprehensive summary of our current knowledge on the role of MIF in obesity, its production by adipose tissue, and its involvement in the development of insulin resistance, type 2 diabetes, and NAFLD. We discuss the main findings from recent clinical studies in obese subjects and weight-loss intervention studies as well as results from clinical studies in patients with insulin resistance and type 2 diabetes. Furthermore, we summarize findings from experimental disease models studying the contribution of MIF in obesity and insulin resistance, type 2 diabetes, and hepatic lipid accumulation and fibrosis. Although many of the findings support a pro-inflammatory role of MIF in disease development, recent reports also provide indications that MIF may exert protective effects under certain conditions.

Urban Political Ecology of Food Poverty in Affluent Developed Societies
Morrison, Sunny - \ 2014
Urban Food Insecurity in Developed Affluent Societies - the case of Riga, Latvia
Morrison, Sunny - \ 2014
Expanding the Theoretical and Policy Reach of Food Sovereignty to Encompass the Issue of Food Poverty within the Wider Concerns of Urban Food Governance – focus on Riga, Latvia
Morrison, Sunny - \ 2014
Control of Competence for DNA Transformation in Streptococcus suis by Genetically Transferable Pherotypes
Zaccaria, E. ; Baarlen, P. van; Greeff, A. de; Morrison, D.A. ; Smith, H. ; Wells, J.M. - \ 2014
PLoS One 9 (2014)6. - ISSN 1932-6203 - 8 p.
horizontal gene-transfer - bacterial transformation - haemophilus-influenzae - peptide pheromone - pneumoniae - thermophilus - activation - expression - regulator - system
Here we show that S. suis, a major bacterial pathogen of pigs and emerging pathogen in humans responds to a peptide pheromone by developing competence for DNA transformation. This species does not fall within any of the phylogenetic clusters of streptococci previously shown to regulate competence via peptide pheromones suggesting that more species of streptococci may be naturally competent. Induction of competence was dependent on ComX, a sigma factor that controls the streptococcal late competence regulon, extracellular addition of a comX-inducing peptide (XIP), and ComR, a regulator of comX. XIP was identified as an N-terminally truncated variant of ComS. Different comS alleles are present among strains of S. suis. These comS alleles are not functionally equivalent and appear to operate in conjuction with a cognate ComR to regulate comX through a conserved comR-box promoter. We demonstrate that these ‘pherotypes’ can be genetically transferred between strains, suggesting that similar approaches might be used to control competence induction in other lactic acid bacteria that lack ComR/ComS homologues but possess comX and the late competence regulon. The approaches described in this paper to identify and optimize peptide-induced competence may also assist other researchers wishing to identify natural competence in other bacteria. Harnessing natural competence is expected to accelerate genetic research on this and other important streptococcal pathogens and to allow high-throughput mutation approaches to be implemented, opening up new avenues for research.
An Analysis of Food Poverty in Affluent Developed Societies - two Urban Settings
Morrison, S.A. - \ 2013
An Analysis of Food Assistance in Riga, Latvia
Morrison, Sunny - \ 2012
Agrarian Discourses, Land use Change and Sustinable Food Systems in Latvia
Morrison, Sunny - \ 2012
Agrarian Discourses, Land use Change and Sustainable Food Systems in Latvia
Morrison, S.A. - \ 2012
Wageningen :
Underrecognized mildly symptomatic viremic dengue virus infections in rural Thai schools and villages
Yoon, I.K. ; Rothman, A.L. ; Tannitisupawong, D. ; Srikiatkhachorn, A. ; Jarman, R.G. ; Aldstadt, J. ; Nisalak, A. ; Mammen Jr., M.P. ; Thammapalo, S. ; Green, S. ; Libraty, D.H. ; Gibbons, R.V. ; Getis, A. ; Endy, T. ; Jones, J.W. ; Koenraadt, C.J.M. ; Morrison, A.C. ; Fansiri, T. ; Pimgate, C. ; Scott, T.W. - \ 2012
The Journal of Infectious Diseases 206 (2012)3. - ISSN 0022-1899 - p. 389 - 398.
kamphaeng phet - aedes-aegypti - transmission - children - epidemiology - blood - surveillance - inapparent - indonesia - patterns
BACKGROUND: The understanding of dengue virus (DENV) transmission dynamics and the clinical spectrum of infection are critical to informing surveillance and control measures. Geographic cluster studies can elucidate these features in greater detail than cohort studies alone. METHODS: A 4-year longitudinal cohort and geographic cluster study was undertaken in rural Thailand. Cohort children underwent pre-/postseason serology and active school absence-based surveillance to detect inapparent and symptomatic dengue. Cluster investigations were triggered by cohort dengue and non-dengue febrile illnesses (positive and negative clusters, respectively). RESULTS: The annual cohort incidence of symptomatic dengue ranged from 1.3% to 4.4%. DENV-4 predominated in the first 2 years, DENV-1 in the second 2 years. The inapparent-to-symptomatic infection ratio ranged from 1.1:1 to 2.9:1. Positive clusters had a 16.0% infection rate, negative clusters 1.1%. Of 119 infections in positive clusters, 59.7% were febrile, 20.2% were afebrile with other symptoms, and 20.2% were asymptomatic. Of 16 febrile children detected during cluster investigations who continued to attend school, 9 had detectable viremia. CONCLUSIONS: Dengue transmission risk was high near viremic children in both high- and low-incidence years. Inapparent infections in the cohort overestimated the rate of asymptomatic infections. Ambulatory children with mild febrile viremic infections could represent an important component of dengue transmission.
Fine Scale Spatiotemporal Clustering of Dengue Virus Transmission in Children and Aedes aegypti in Rural Thai Villages
Yoon, I.K. ; Getis, A. ; Aldstadt, J. ; Rothman, A.L. ; Tannitisupawong, D. ; Koenraadt, C.J.M. ; Fansiri, T. ; Jones, J.W. ; Morrison, A.C. ; Jarman, R.G. ; Nisalak, A. ; Mammen Jr., M.P. ; Thammapalo, S. ; Srikiatkhachorn, A. ; Green, S. ; Libraty, D.H. ; Gibbons, R.V. ; Endy, T. ; Pimgate, C. ; Scott, T.W. - \ 2012
PLoS Neglected Tropical Diseases 6 (2012)7. - ISSN 1935-2727
polymerase-chain-reaction - primary-school children - kamphaeng phet - puerto-rico - vector - culicidae - diptera - blood - patterns - kinetics
Background Based on spatiotemporal clustering of human dengue virus (DENV) infections, transmission is thought to occur at fine spatiotemporal scales by horizontal transfer of virus between humans and mosquito vectors. To define the dimensions of local transmission and quantify the factors that support it, we examined relationships between infected humans and Aedes aegypti in Thai villages. Methodology/Principal Findings Geographic cluster investigations of 100-meter radius were conducted around DENV-positive and DENV-negative febrile “index” cases (positive and negative clusters, respectively) from a longitudinal cohort study in rural Thailand. Child contacts and Ae. aegypti from cluster houses were assessed for DENV infection. Spatiotemporal, demographic, and entomological parameters were evaluated. In positive clusters, the DENV infection rate among child contacts was 35.3% in index houses, 29.9% in houses within 20 meters, and decreased with distance from the index house to 6.2% in houses 80–100 meters away (p
Biochemical Characterization and Relative Expression Levels of Multiple Carbohydrate Esterases of the Xylanolytic Rumen Bacterium Prevotella ruminicola 23 Grown on an Ester-Enriched Substrate
Kabel, M.A. ; Yeoman, C.J. ; Han, Y. ; Dodd, D. ; Abbas, C.A. ; Bont, J.A.M. de; Morrison, M. ; Cann, I.K.O. ; Mackie, R.I. - \ 2011
Applied and Environmental Microbiology 77 (2011)16. - ISSN 0099-2240 - p. 5671 - 5681.
predicting subcellular-localization - eucalyptus-globulus labill - xylo-oligosaccharides - acetyl xylan - cell-wall - structural features - ferulic acid - maize bran - specificity - hydrolysis
We measured expression and used biochemical characterization of multiple carbohydrate esterases by the xylanolytic rumen bacterium Prevotella ruminicola 23 grown on an ester-enriched substrate to gain insight into the carbohydrate esterase activities of this hemicellulolytic rumen bacterium. The P. ruminicola 23 genome contains 16 genes predicted to encode carbohydrate esterase activity, and based on microarray data, four of these were upregulated >2-fold at the transcriptional level during growth on an ester-enriched oligosaccharide (XOSFA,Ac) from corn relative to a nonesterified fraction of corn oligosaccharides (AXOS). Four of the 16 esterases (Xyn10D-Fae1A, Axe1-6A, AxeA1, and Axe7A), including the two most highly induced esterases (Xyn10D-Fae1A and Axe1-6A), were heterologously expressed in Escherichia coli, purified, and biochemically characterized. All four enzymes showed the highest activity at physiologically relevant pH (6 to 7) and temperature (30 to 40°C) ranges. The P. ruminicola 23 Xyn10D-Fae1A (a carbohydrate esterase [CE] family 1 enzyme) released ferulic acid from methylferulate, wheat bran, corn fiber, and XOSFA,Ac, a corn fiber-derived substrate enriched in O-acetyl and ferulic acid esters, but exhibited negligible activity on sugar acetates. As expected, the P. ruminicola Axe1-6A enzyme, which was predicted to possess two distinct esterase family domains (CE1 and CE6), released ferulic acid from the same substrates as Xyn10D-Fae1 and was also able to cleave O-acetyl ester bonds from various acetylated oligosaccharides (AcXOS). The P. ruminicola 23 AxeA1, which is not assigned to a CE family, and Axe7A (CE7) were found to be acetyl esterases that had activity toward a broad range of mostly nonpolymeric acetylated substrates along with AcXOS. All enzymes were inhibited by the proximal location of other side groups like 4-O-methylglucuronic acid, ferulic acid, or acetyl groups. The unique diversity of carbohydrate esterases in P. ruminicola 23 likely gives it the ability to hydrolyze substituents on the xylan backbone and enhances its capacity to efficiently degrade hemicellulose.
Development of a European system for identification of emerging mycotoxins in wheat supply chains
Fels-Klerx, H.J. van der; Kandhai, M.C. ; Brynestad, S. ; Dreyer, M. ; Borjesson, T. ; Martins, M. ; Uiterwijk, M. ; Morrison, E. ; Booij, C.J.H. - \ 2009
World Mycotoxin Journal 2 (2009)2. - ISSN 1875-0710 - p. 119 - 127.
winter-wheat - food safety - fusarium - samples
This paper describes the results of a research project aimed at the conceptual development of an identification system for emerging mycotoxins in European feed and food supply chains of wheat. Basic requirements for such a system were addressed, including the selection of indicators, locating information sources, development of underlying model, and investigation of stakeholders' needs. The selection and ranking of key indicators for identifying emerging mycotoxins was based on a literature review, followed by a structured expert judgment study. The expert study was based on the Delphi technique and used a panel of 43 European experts. The Delphi procedure resulted in a selected set of 12 key indicators for each of three relevant stages of the wheat chain (cultivation; transport and storage; processing). For wheat cultivation, these were: relative humidity/rainfall, crop rotation, temperature, tillage practice, water activity in the kernels, crop variety, harvest conditions, changes in fungal populations, fungicide use, plant health, regional infection pressure and food safety awareness. For the majority of the selected indicators, information sources were identified in specific European countries. However, most sources are not readily accessible and particular data is lacking. A theoretical concept for a model underlying the envisioned emerging mycotoxin identification system has been developed. The model links the key indicators and their information sources to aid and promote identification of emerging mycotoxins. It manages different types of information sources and levels of available information. The needs of various stakeholder groups regarding the system were investigated by means of two empirical elicitation sessions. The results showed that all stakeholders considered that such a system would be beneficial. One major challenge expected in establishing the system is stakeholder commitment to sharing data and information. This requires great efforts in improving communication and interaction between the key stakeholders
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