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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    Small angle neutron scattering quantifies the hierarchical structure in fibrous calcium caseinate
    Tian, Bei ; Wang, Zhaojun ; Campo, Liliana de; Gilbert, Elliot P. ; Dalgliesh, Robert M. ; Velichko, Evgenii ; Goot, Atze Jan van der; Bouwman, Wim G. - \ 2020
    Food Hydrocolloids 106 (2020). - ISSN 0268-005X
    Anisotropic Guinier–Porod model - Calcium caseinate - Fibrous structure - Mechanical property - Small angle neutron scattering (SANS)

    Pronounced fibres are formed through simple shearing of a dense calcium caseinate dispersion. Both mechanical tests and scanning electron microscopy images demonstrate that the material is anisotropic. It is hypothesised that calcium caseinate aggregates, under shear, align into micro-fibres and bundle further into a hierarchical structure. Yet no direct evidence at the sub-micron length scale can support the assumption. Small angle neutron scattering (SANS) experiments were conducted on calcium caseinate samples prepared at different conditions. Analysis of the SANS data revealed that the micro-fibres have a diameter of ∼100nm and a length of ∼300nm. The addition of enzyme and air contributed to longer and thinner micro-fibres. Furthermore, the extent of fibre alignment at the micro-scale and the macroscopic anisotropy index followed the same trends with varying processing conditions. It is concluded that the material does indeed possess a hierarchical structure and the micro-fibres are responsible for the anisotropy on the macro-scale.

    Effect of fructans, prebiotics and fibres on the human gut microbiome assessed by 16S rRNA-based approaches : a review
    Swanson, K.S. ; Vos, W.M. de; Martens, E.C. ; Gilbert, J.A. ; Menon, R.S. ; Soto-Vaca, A. ; Hautvast, J. ; Meyer, P.D. ; Borewicz, K. ; Vaughan, E.E. ; Slavin, J.L. - \ 2020
    Beneficial Microbes 11 (2020)2. - ISSN 1876-2883 - p. 101 - 129.
    health - intestine - inulin - microbiota - nutrition

    The inherent and diverse capacity of dietary fibres, nondigestible oligosaccharides (NDOs) and prebiotics to modify the gut microbiota and markedly influence health status of the host has attracted rising interest. Research and collective initiatives to determine the composition and diversity of the human gut microbiota have increased over the past decade due to great advances in high-throughput technologies, particularly the 16S ribosomal RNA (rRNA) sequencing. Here we reviewed the application of 16S rRNA-based molecular technologies, both community wide (sequencing and phylogenetic microarrays) and targeted methodologies (quantitative PCR, fluorescent in situ hybridisation) to study the effect of chicory inulin-type fructans, NDOs and specific added fibres, such as resistant starches, on the human intestinal microbiota. Overall, such technologies facilitated the monitoring of microbiota shifts due to prebiotic/fibre consumption, though there are limited community-wide sequencing studies so far. Molecular studies confirmed the selective bifidogenic effect of fructans and galactooligosaccharides (GOS) in human intervention studies. Fructans only occasionally decreased relative abundance of Bacteroidetes or stimulated other groups. The sequencing studies for various resistant starches, polydextrose and beta-glucan showed broader effects with more and different types of gut microbial species being enhanced, often including phylotypes of Ruminococcaceae. There was substantial variation in terms of magnitude of response and in individual responses to a specific fibre or NDO which may be due to numerous factors, such as initial presence and relative abundance of a microbial type, diet, genetics of the host, and intervention parameters, such as intervention duration and fibre dose. The field will clearly benefit from a more systematic approach that will support defining the impact of prebiotics and fibres on the gut microbiome, identify biomarkers that link gut microbes to health, and address the personalised response of an individual's microbiota to prebiotics and dietary fibres.

    Nitrogen and Amino Acid Digesta Flows in Broilers fed Heat Damaged Protein Ingredients
    Elling-Staats, M.L. ; Kies, Arie ; Gilbert, M.S. ; Kwakkel, R.P. - \ 2020
    In: Wias Annual Conference 2020. - WIAS - p. 39 - 39.
    Due to an increasing feed-food competition for quality protein, less digestible protein is expected to be fed to broilers in the future. However, pre-caecal indigestible protein in the diets of broilers may lead to hind-gut protein fermentation (PF) and the production of potentially health detrimental metabolites. To evaluate effects of PF on gut health, an experimental contrast in ileal N flow is required. Therefore, our objective was to develop a model that creates a contrast in protein fermentation by reducing protein digestibility within ingredients. To this end, we used severe toasting of protein sources and evaluated the effect on ileal nitrogen (N) and amino acid (AA) flows. Distal ileum content, excreta and caeca content were collected from 240 broilers fed one of six diets (8 replicate pens) for 30 days. Diets contained 20% soybean meal (SBM), high protein sunflower meal (SFM) or dehulled rape-seed meal (dRSM) as is, or heat damaged by secondary toasting at 136°C for 20 minutes (tSBM, tSFM or tdRSM). Toasting SBM increased the ileal flow of N (851 vs. 744 mg/d) and most of the AA (on average by 35 mg/d). The daily excreted N (excluding uric acid N) level did not differ between SBM and tSBM diets, some AA levels increased, such as Asp, Glu and Lys (mean increase: 34 mg/d). Toasting SFM had no effect on the flow of N and AA. Toasting dRSM increased the flow of N (862 vs. 665 mg/d) and all AA (mean increase 56 mg/day) through the distal ileum. Also, the excreted flow was increased: N (999 vs. 761 mg/d, excluding uric acid N) and AA (mean 71 mg/d). In conclusion, toasting dRSM, and to a lesser extend SBM, increased the flow of PF substrate into the hindgut of broilers, making these potential models to evaluate effects of PF on gut health. Whether these increased ileal flows of N and AA lead to increased PF will be further studied by caecal PF metabolite concentrations. The increase in N and AA from ileum to excreta might be the result of microbial growth. Microbe quantification will be Dneeded to elucidate whether this is the case.
    Post-weaning diarrhoea is associated with protein fermentation, alterations in intestinal microbiota, and host physiological parameters in piglets
    Hee, B. van der; Gilbert, M.S. ; Kies, Arie ; Fernandez Gutierrez, M.M. ; Vries, H.J.A. de; Taverne, N. ; Taverne-Thiele, J.J. ; Heikamp-de Jong, G.A.M. ; Gaal, Merlijn van; Gerrits, W.J.J. ; Smidt, H. ; Wells, J.M. - \ 2020
    In: WIAS Annual Conference 2020. - WIAS - p. 29 - 29.
    In Dutch farming, piglets are commonly weaned abruptly around 28 days of age. This abrupt separation from the sow is often associated with a check in feed intake, intestinal morphological changes, and/or aberrations in microbiota composition and activity. Furthermore, the ability to digest solid feed is often underdeveloped, and due to the sudden shift in dietary source often leads to decreased digestion of dietary components, such as protein, in the small intestine. This ultimately leads to a higher flow of undigested nutrients into the colon. In the colon, the long residence time and limited nutrient absorption facilitate microbial proteolysis and accumulation of metabolic end products some of which may be detrimental to the host. Results of our on-farm studies have shown a strong negative correlation between ammonia concentration and dry matter content of the faeces, indicating that diarrhoea is associated with increased ammonia. Furthermore, profiling of the microbial composition revealed an increase in the relative abundance of bacterial groups known for their protein fermenting capacity, and absolute concentrations of genes encoding for specific diarrhoeic toxins, in animals suffering from diarrhoea. To model direct intestinal responses, we assessed molecular mechanisms in our two-dimensional organoid model using protein fermentation metabolites ammonia and hydrogen sulphide, each eliciting distinct cellular responses. From this, we conclude that there are associations between protein fermentation and intestinal health in piglets post-weaning.
    Identification de biomarqueurs de l'efficacité alimentaire chez le porc en croissance
    Gondret, Florence ; Skou Hedeman, Mette ; Messad, Farouk ; Verschuren, Lisanne ; Wang, Junjun ; Fuente, Gabriel de la; Gilbert, Hélène ; Jansman, A.J.M. - \ 2020
    In: 52èmes Journées de la Recherche Porcine. - IFIP, INRA - p. 20 - 24.
    International scientists formulate a roadmap for insect conservation and recovery
    Harvey, Jeffrey A. ; Heinen, Robin ; Armbrecht, Inge ; Basset, Yves ; Baxter-Gilbert, James H. ; Bezemer, T.M. ; Böhm, Monika ; Bommarco, Riccardo ; Borges, Paulo A.V. ; Cardoso, Pedro ; Clausnitzer, Viola ; Cornelisse, Tara ; Crone, Elizabeth E. ; Dicke, Marcel ; Dijkstra, Klaas Douwe B. ; Dyer, Lee ; Ellers, Jacintha ; Fartmann, Thomas ; Forister, Mathew L. ; Furlong, Michael J. ; Garcia-Aguayo, Andres ; Gerlach, Justin ; Gols, Rieta ; Goulson, Dave ; Habel, Jan Christian ; Haddad, Nick M. ; Hallmann, Caspar A. ; Henriques, Sérgio ; Herberstein, Marie E. ; Hochkirch, Axel ; Hughes, Alice C. ; Jepsen, Sarina ; Jones, T.H. ; Kaydan, Bora M. ; Kleijn, David ; Klein, Alexandra Maria ; Latty, Tanya ; Leather, Simon R. ; Lewis, Sara M. ; Lister, Bradford C. ; Losey, John E. ; Lowe, Elizabeth C. ; Macadam, Craig R. ; Montoya-Lerma, James ; Nagano, Christopher D. ; Ogan, Sophie ; Orr, Michael C. ; Painting, Christina J. ; Pham, Thai Hong ; Potts, Simon G. ; Rauf, Aunu ; Roslin, Tomas L. ; Samways, Michael J. ; Sanchez-Bayo, Francisco ; Sar, Sim A. ; Schultz, Cheryl B. ; Soares, António O. ; Thancharoen, Anchana ; Tscharntke, Teja ; Tylianakis, Jason M. ; Umbers, Kate D.L. ; Vet, Louise E.M. ; Visser, Marcel E. ; Vujic, Ante ; Wagner, David L. ; Wallis DeVries, Michiel F. ; Westphal, Catrin ; White, Thomas E. ; Wilkins, Vicky L. ; Williams, Paul H. ; Wyckhuys, Kris A.G. ; Zhu, Zeng Rong ; Kroon, Hans de - \ 2020
    Nature Ecology & Evolution 4 (2020)4. - ISSN 2397-334X - p. 174 - 176.
    The role of protein fermentation metabolites in post-weaning diarrhoea in piglets
    Gilbert, Myrthe - \ 2019
    The role of protein fermentation metabolites in post-weaning diarrhoea in piglets
    Gilbert, M.S. ; Hee, B. van der; Gerrits, W.J.J. - \ 2019
    In: Energy and protein metabolism and nutrition. - Wageningen Academic Publishers (EAAP Publication 138) - ISBN 9789086863402 - p. 361 - 362.
    Summary Results WP5: Use of traits in animal selection
    Gilbert, H. ; Calus, Mario - \ 2019
    Soil as a basis to create enabling conditions for transitions towards sustainable land management as a key to achieve the SDGs by 2030
    Visser, Saskia ; Keesstra, Saskia ; Maas, Gilbert ; Cleen, Margot de; Molenaar, Co - \ 2019
    Sustainability 11 (2019)23. - ISSN 2071-1050
    Land degradation neutrality - New business models - Sustainable development goals - Sustainable land management - Transition science - Transitions

    The Sustainable Development Goals (SDGs) can be grouped into three domains, the environmental domain, the social domain and the economic domain. These different layers influence each other; hence sustainable progress in the economic layer cannot be achieved without good progress in the two other layers. To achieve the SDGs, transitions in the current system are needed and actions should be taken that support transitions and contribute to short term needs and long term (global) goals. Therefore, it is necessary to have knowledge of transitions and understand the different phases of transition. In this paper we discuss the key role of the soil-water system in these transitions and the achievement of the SDGs by 2030. The increasing pressure on land calls for multi-use of land and for the restoration of degraded land. Healthy soils and healthy land are the basic conditions for the successful implementation and realization of the SDGs. To enable a sustainable management of the soil and water system a transition approach is a prerequisite. In the X-curve used to describe transitions, soil and land stakeholders are given a framework, which provides perspective for action, specifically for science and governance stakeholders in each phase of the transition. This framework can provide the required intensive guidance to (1) analyze the impact of provided incentives, (2) identify new reference points in the transition and (3) stimulate transition catalysts, and (iv) innovate by testing cutting edge policy instruments in close cooperation with society. The key to make the necessary transitions and realize the SDGs by 2030 lies in the intensive guidance to combining initiatives, steering knowledge flows and continuously assessing the stage of the transition, in order to plan specific steps needed to progress in the transition framework. Both scientist and policy makers have an important role in this guidance.

    Aflatoxin B1 in nixtamalized maize in Mexico; occurrence and accompanying risk assessment
    Gilbert Sandoval, Ixchel ; Wesseling, Sebastiaan ; Rietjens, Ivonne M.C.M. - \ 2019
    Toxicology Reports 6 (2019). - ISSN 2214-7500 - p. 1135 - 1142.
    Aflatoxin B1 - Liver cancer - Maize - Margin of exposure (MOE) - Mexico - Risk assessment

    Maize is a staple food in Mexico that might contain Aflatoxin B1 (AFB1). Nonetheless, data on the exposure and risk assessment of AFB1 from maize for the Mexican population are limited. The aim of the present study was to analyse the occurrence of AFB1 in Mexican nixtamalized maize samples, and to assess the accompanying exposure and risk. Four out of 88 samples contained AFB1 at levels above the limit of detection (1 ng/g). AFB1 occurrence values obtained in this study and additional occurrence values from literature were combined with available literature data for mean and P95 consumption of maize based products. For a 70 kg body weight person, lower bound and upper bound exposure assessments resulted in estimated daily intakes (EDI) of 0.7–8.5 ng/kg bw/day, based on a mean maize consumption. Based on the P95 maize consumption these EDI values amounted to 3.3–11.7 ng/kg bw/day. The corresponding Margin of Exposure (MOE) values amounted to 257-20 for the mean and 50-15 for the P95 consumers. The estimated increased cancer risks were 9-320 and 43-439 cases/106 individuals/lifetime of 75 years for the mean and P95 consumers, respectively. Altogether, the assessment reveals the need for continued risk management of AFB1 in Mexico.

    Safety and efficacy of ChAdOx1 RVF vaccine against Rift Valley fever in pregnant sheep and goats
    Stedman, Anna ; Wright, Daniel ; Wichgers Schreur, Paul J. ; Clark, Madeleine H.A. ; Hill, Adrian V.S. ; Gilbert, Sarah C. ; Francis, Michael J. ; Keulen, Lucien van; Kortekaas, Jeroen ; Charleston, Bryan ; Warimwe, George M. - \ 2019
    Vaccines 4 (2019)1. - ISSN 2076-393X

    Rift Valley fever virus (RVFV) is a zoonotic mosquito-borne virus that was first discovered in Kenya in 1930 and has since spread to become endemic in much of Africa and the Arabian Peninsula. Rift Valley fever (RVF) causes recurrent outbreaks of febrile illness associated with high levels of mortality and poor outcomes during pregnancy—including foetal malformations, spontaneous abortion and stillbirths—in livestock, and associated with miscarriage in humans. No vaccines are available for human use and those licensed for veterinary use have potential drawbacks, including residual virulence that may contraindicate their use in pregnancy. To address this gap, we previously developed a simian adenovirus vectored vaccine, ChAdOx1 RVF, that encodes RVFV envelope glycoproteins. ChAdOx1 RVF is fully protective against RVF in non-pregnant livestock and is also under development for human use. Here, we now demonstrate that when administered to pregnant sheep and goats, ChAdOx1 RVF is safe, elicits high titre RVFV neutralizing antibody, and provides protection against viraemia and foetal loss, although this protection is not as robust for the goats. In addition, we provide a description of RVFV challenge in pregnant goats and contrast this to the pathology observed in pregnant sheep. Together, our data further support the ongoing development of ChAdOx1 RVF vaccine for use in livestock and humans.

    Forensic microbiology reveals that Neisseria animaloris infections in harbour porpoises follow traumatic injuries by grey seals
    Foster, Geoffrey ; Whatmore, Adrian M. ; Dagleish, Mark P. ; Malnick, Henry ; Gilbert, Maarten J. ; Begeman, Lineke ; Macgregor, Shaheed K. ; Davison, Nicholas J. ; Roest, Hendrik Jan ; Jepson, Paul ; Howie, Fiona ; Muchowski, Jakub ; Brownlow, Andrew C. ; Wagenaar, Jaap A. ; Kik, Marja J.L. ; Deaville, Rob ; Doeschate, Mariel T.I. ten; Barley, Jason ; Hunter, Laura ; IJsseldijk, Lonneke L. - \ 2019
    Scientific Reports 9 (2019). - ISSN 2045-2322

    Neisseria animaloris is considered to be a commensal of the canine and feline oral cavities. It is able to cause systemic infections in animals as well as humans, usually after a biting trauma has occurred. We recovered N. animaloris from chronically inflamed bite wounds on pectoral fins and tailstocks, from lungs and other internal organs of eight harbour porpoises. Gross and histopathological evidence suggest that fatal disseminated N. animaloris infections had occurred due to traumatic injury from grey seals. We therefore conclude that these porpoises survived a grey seal predatory attack, with the bite lesions representing the subsequent portal of entry for bacteria to infect the animals causing abscesses in multiple tissues, and eventually death. We demonstrate that forensic microbiology provides a useful tool for linking a perpetrator to its victim. Moreover, N. animaloris should be added to the list of potential zoonotic bacteria following interactions with seals, as the finding of systemic transfer to the lungs and other tissues of the harbour porpoises may suggest a potential to do likewise in humans.

    Ancient pigs reveal a near-complete genomic turnover following their introduction to Europe
    Frantz, Laurent A.F. ; Haile, James ; Lin, Audrey T. ; Scheu, Amelie ; Geörg, Christina ; Benecke, Norbert ; Alexander, Michelle ; Linderholm, Anna ; Mullin, Victoria E. ; Daly, Kevin G. ; Battista, Vincent M. ; Price, Max ; Gron, Kurt J. ; Alexandri, Panoraia ; Arbogast, Rose Marie ; Arbuckle, Benjamin ; Bǎlǎşescu, Adrian ; Barnett, Ross ; Bartosiewicz, László ; Baryshnikov, Gennady ; Bonsall, Clive ; Borić, Dušan ; Boroneanţ, Adina ; Bulatović, Jelena ; Çakirlar, Canan ; Carretero, José Miguel ; Chapman, John ; Church, Mike ; Crooijmans, Richard ; Cupere, Bea De; Detry, Cleia ; Dimitrijevic, Vesna ; Dumitraşcu, Valentin ; Plessis, Louis Du; Edwards, Ceiridwen J. ; Erek, Cevdet Merih ; Erim-Özdoǧan, Asli ; Ervynck, Anton ; Fulgione, Domenico ; Gligor, Mihai ; Götherström, Anders ; Gourichon, Lionel ; Groenen, Martien A.M. ; Helmer, Daniel ; Hongo, Hitomi ; Horwitz, Liora K. ; Irving-Pease, Evan K. ; Lebrasseur, Ophélie ; Lesur, Joséphine ; Malone, Caroline ; Manaseryan, Ninna ; Marciniak, Arkadiusz ; Martlew, Holley ; Mashkour, Marjan ; Matthews, Roger ; Matuzeviciute, Giedre Motuzaite ; Maziar, Sepideh ; Meijaard, Erik ; McGovern, Tom ; Megens, Hendrik Jan ; Miller, Rebecca ; Mohaseb, Azadeh Fatemeh ; Orschiedt, Jörg ; Orton, David ; Papathanasiou, Anastasia ; Pearson, Mike Parker ; Pinhasi, Ron ; Radmanović, Darko ; Ricaut, François Xavier ; Richards, Mike ; Sabin, Richard ; Sarti, Lucia ; Schier, Wolfram ; Sheikhi, Shiva ; Stephan, Elisabeth ; Stewart, John R. ; Stoddart, Simon ; Tagliacozzo, Antonio ; Tasić, Nenad ; Trantalidou, Katerina ; Tresset, Anne ; Valdiosera, Cristina ; Hurk, Youri Van Den; Poucke, Sophie Van; Vigne, Jean Denis ; Yanevich, Alexander ; Zeeb-Lanz, Andrea ; Triantafyllidis, Alexandros ; Gilbert, M.T.P. ; Schibler, Jörg ; Rowley-Conwy, Peter ; Zeder, Melinda ; Peters, Joris ; Cucchi, Thomas ; Bradley, Daniel G. ; Dobney, Keith ; Burger, Joachim ; Evin, Allowen ; Girdland-Flink, Linus ; Larson, Greger - \ 2019
    Proceedings of the National Academy of Sciences of the United States of America 116 (2019)35. - ISSN 0027-8424 - p. 17231 - 17238.
    Domestication - Evolution - Gene flow - Neolithic

    Archaeological evidence indicates that pig domestication had begun by ∼10,500 y before the present (BP) in the Near East, and mitochondrial DNA (mtDNA) suggests that pigs arrived in Europe alongside farmers ∼8,500 y BP. A few thousand years after the introduction of Near Eastern pigs into Europe, however, their characteristic mtDNA signature disappeared and was replaced by haplotypes associated with European wild boars. This turnover could be accounted for by substantial gene flow from local European wild boars, although it is also possible that European wild boars were domesticated independently without any genetic contribution from the Near East. To test these hypotheses, we obtained mtDNA sequences from 2,099 modern and ancient pig samples and 63 nuclear ancient genomes from Near Eastern and European pigs. Our analyses revealed that European domestic pigs dating from 7,100 to 6,000 y BP possessed both Near Eastern and European nuclear ancestry, while later pigs possessed no more than 4% Near Eastern ancestry, indicating that gene flow from European wild boars resulted in a near-complete disappearance of Near East ancestry. In addition, we demonstrate that a variant at a locus encoding black coat color likely originated in the Near East and persisted in European pigs. Altogether, our results indicate that while pigs were not independently domesticated in Europe, the vast majority of human-mediated selection over the past 5,000 y focused on the genomic fraction derived from the European wild boars, and not on the fraction that was selected by early Neolithic farmers over the first 2,500 y of the domestication process.

    Metatranscriptomics reveals mycoviral populations in the ovine rumen
    Hitch, Thomas C.A. ; Edwards, Joan E. ; Gilbert, Rosalind A. - \ 2019
    FEMS Microbiology Letters 366 (2019)13. - ISSN 0378-1097
    fungi - mycobiome - mycovirus - RNA - rumen

    The rumen is known to contain DNA-based viruses, although it is not known whether RNA-based viruses that infect fungi (mycoviruses) are also present. Analysis of publicly available rumen metatranscriptome sequence data from sheep rumen samples (n = 20) was used to assess whether RNA-based viruses exist within the ovine rumen. A total of 2466 unique RNA viral contigs were identified that had homology to nine viral families. The Partitiviridae was the most consistently observed mycoviral family. High variation in the abundance of each detected mycovirus suggests that rumen mycoviral populations vary greatly between individual sheep. Functional analysis of the genes within the assembled mycoviral contigs suggests that the mycoviruses detected had simple genomes, often only carrying the machinery required for replication. The fungal population of the ovine rumen was also assessed using metagenomics data from the same samples, and was consistently dominated by the phyla Ascomycota and Basidomycota. The strictly anaerobic phyla Neocallimastigomycota were also present in all samples but at a low abundance. This preliminary investigation has provided clear evidence that mycoviruses with RNA genomes exist in the rumen, with further in-depth studies now required to characterise this mycoviral community and determine its role in the rumen.

    A predictive strategy for mapping locations where future MOSSFA events are expected
    Murk, A.J. ; Hollander, D.J. ; Chen, S. ; Hu, C. ; Liu, Y. ; Vonk, S.M. ; Schwing, Patrick T. ; Gilbert, S. ; Foekema, E.M. - \ 2019
    In: Scenarios and Responses to Future Deep Oil Spills / Murawski, S.A., Ainsworth, C.H., Gilbert, S., Hollander, D.J., Paris, C.B., Schlueter, M., Wetzel, D.L., - p. 355 - 368.
    A MOSSFA (marine oil snow sedimentation and flocculent accumulation) event was the reason that substantial amounts of the spilled oil were transported to the seafloor during the Deepwater Horizon (DWH) oil well blowout. The region-wide sinking and flocculent accumulation of marine oil snow on the sediment surface changed redox conditions, slowed down the biodegradation of the oil, and increased the spatial and temporal impacts on the benthic community and habitat suitability. Recent field research has confirmed that, in addition to the DWH MOSSFA event in the northern Gulf of Mexico (nGoM), another extensive MOSSFA event occurred in a biologically sensitive area in the southern Gulf of Mexico (sGoM) during the 1979 - 1980 Ixtoc I oil well blowout. Thus, MOSSFA events are not unexpected and have the potential to not only alter sediment chemical conditions but also to extend, expand, and intensify the ecological impact of an oil spill. Consequently this risk should be taken into consideration when preparing response...
    Effect of marine snow on microbial oil degradation
    Langenhoff, A.A.M. ; Rahsepar, Shokouh ; Eenennaam, J.S. van; Radović, Jagoš R. ; Oldenburg, Thomas B.P. ; Foekema, E.M. ; Murk, A.J. - \ 2019
    In: Deep Oil Spills / Murawski, S.A., Ainsworth, C.H., Gilbert, S., Hollander, D.J., Paris, C.B., Schlueter, M., Wetzel, D.L., Springer Nature Switzerland - ISBN 9783030116040 - p. 301 - 311.
    In the aftermath of an oil spill, a possible response is the addition of chemical dispersants to prevent further spreading of the spilled oil on the ocean surface. The main objective is to enhance the formation of smaller oil droplets by reducing the interfacial tension between oil and water, thus dispersing the oil into the water column. The resulting solubilized oil with microdroplets along with the associated toxic compounds will be swiftly incorporated into the seawater. The formation of smaller oil droplets and the dispersant enhanced solubilized oil will increase its availability for bacteria and thus the biodegradability. Subsequently, the number and activity of oil-degrading bacteria increases, and more oil will be degraded in a shorter period of time (Kessler et al., Science 331:312–315, 2011). However, during the immediate release of the dispersed oil, volatile hydrocarbons including some of the more toxic compounds of benzene, toluene, ethylbenzene, and xylenes (BTEX) can inhibit the oil degradation (Sherry et al., Front Microbiol 5:131, 2014).
    Depending on the oceanic conditions, the addition of chemical dispersants can result in excessive formation of marine snow. It has been shown that the application of dispersants during phytoplankton blooms can trigger the formation of marine snow to which the sticky dispersed oil can bind. In the presence of mineral particles, oiled snow complexes are being formed that become negatively buoyant and sink to the ocean floor. As a result, oiled marine snow accumulates on the ocean floor where biodegradation is inhibited due to oxygen depletion.
    The abovementioned two mechanisms of inhibition of oil biodegradation upon application of oil spill dispersants will be discussed in this chapter.
    Testing the Effect of MOSSFA (Marine Oil Snow Sedimentation and Flocculent Accumulation) Events in Benthic Microcosms
    Foekema, E.M. ; Eenennaam, Justine van; Hollander, D.J. ; Langenhoff, A.A.M. ; Oldenburg, Thomas B.P. ; Radović, Jagoš R. ; Rohal, Melissa ; Romero, Isabel C. ; Schwing, Patrick T. ; Murk, A.J. - \ 2019
    In: Scenarios and Responses to Future Deep Oil Spills / Murawski, S.A., Ainsworth, C.H., Gilbert, S., Hollander, D.J., Paris, C.B., Schlueter, M., Wetzel, D.L., Springer Nature Switzerland - ISBN 9783030129620 - p. 288 - 299.
    In multispecies experiments performed in microcosms with natural sediment, it was investigated how the presence of marine snow affects the fate and ecological impact of deposited oil residues. The response of different taxonomic groups like nematodes, foraminifera, crustaceans and molluscs onto the presence of marine snow with or without oil was compared with the impact of deposited oil residues without marine snow. Also the effect of the presence of marine snow on oil biodegradation and transfer for oil-derived compounds to selected biota was studied. Although not designed to mimic the specific deep sea conditions in the Gulf of Mexico, the outcome of the experiments gave new insights in how a MOSSFA event can affect the benthic community. In general the experments indicated that at field realistic oil-derived compound concentrations, the adverse impact of the marine snow on the sediment surface has a stronger impact on the benthic ecosystem than...
    Living in cold blood: Arcobacter, Campylobacter, and Helicobacter in reptiles
    Gilbert, Maarten J. ; Duim, Birgitta ; Zomer, Aldert L. ; Wagenaar, Jaap A. - \ 2019
    Frontiers in Microbiology 10 (2019)MAY. - ISSN 1664-302X
    Arcobacter - Biodiversity - Campylobacter - Ecology - Epsilonproteobacteria - Evolution - Helicobacter - Reptile

    Species of the Epsilonproteobacteria genera Arcobacter, Campylobacter, and Helicobacter are commonly associated with vertebrate hosts and some are considered significant pathogens. Vertebrate-associated Epsilonproteobacteria are often considered to be largely confined to endothermic mammals and birds. Recent studies have shown that ectothermic reptiles display a distinct and largely unique Epsilonproteobacteria community, including taxa which can cause disease in humans. Several Arcobacter taxa are widespread amongst reptiles and often show a broad host range. Reptiles carry a large diversity of unique and novel Helicobacter taxa, which apparently evolved in an ectothermic host. Some species, such as Campylobacter fetus, display a distinct intraspecies host dichotomy, with genetically divergent lineages occurring either in mammals or reptiles. These taxa can provide valuable insights in host adaptation and co-evolution between symbiont and host. Here, we present an overview of the biodiversity, ecology, epidemiology, and evolution of reptile-associated Epsilonproteobacteria from a broader vertebrate host perspective.

    Late Quaternary lahars and lava dams: Fluvial responses of the Upper Tana River (Kenya)
    Schoorl, J.M. ; Veldkamp, A. ; Claessens, L. ; Wijbrans, J.R. ; Olago, D.O. ; Lievens, C. - \ 2019
    Geomorphology 341 (2019). - ISSN 0169-555X - p. 28 - 45.
    40 39 Ar/ Ar geochronology - Basalt flows - Delta - Fluvial terrace - Lahar
    Geomorphological and sedimentary records near the confluences of the Tana River and major tributaries draining the eastern slopes of Mt. Kenya and the Nyambeni Range, indicate impacts of Late Quaternary volcanic activity in their fluvial records. The main reconstructed event was triggered by a 366.9 ka basalt flow (40Ar/39Ar dated) which flowed along Kazita River from the Nyambeni Range blocking both Kazita River and Tana River near Kibuka Grand Falls, causing a temporary lake. Consequently, Tana River and Kazita River started to build volcanoclastic Gilbert type deltas. The preserved pro-delta sediments rich in trachytic pumice fragments display a mineralogical and age match with known Ithanguni trachytic tuffs, indicating delta build up right after a contemporary Ithanguni eruption. This trachytic eruption caused the deposition of lahars and fluvial volcaniclastic sediments in all river records draining the Eastern side of Mt. Kenya. The multiple lahars seem to be triggered by eruptions under glacial conditions (basalt age indicates MIS 10). The lava dammed lake was only short lived (estimated to have lasted only a few years to decades) and breached before a complete lake infill could occur. The current Kibuka Grand Falls can be viewed as the delayed incisional response of this lava dam breach, indicating that after >366.9 ka, Tana River is still responding and adjusting to this short-lived disruptive phase. The current Kazita River has re-incised adjacent to a MIS 4 basalt flow down into the crystalline Basement System rocks. The MIS 10 pre-volcanic sedimentary record indicates that more sediments were in the fluvial system during glacial conditions than during the interglacial conditions. An implication of our reconstruction is that the Late Quaternary fluvial record of Tana River is of only limited use to reconstruct uplift rates because reconstructed Quaternary incision rates are reflecting both volcanic disruptions as climate change trends of aridification and decreasing glaciation extents.
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