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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Nutrimetabolomics: An Integrative Action for Metabolomic Analyses in Human Nutritional Studies
Ulaszewska, Marynka M. ; Weinert, Christoph H. ; Trimigno, Alessia ; Portmann, Reto ; Andres Lacueva, Cristina ; Badertscher, René ; Brennan, Lorraine ; Brunius, Carl ; Bub, Achim ; Capozzi, Francesco ; Cialiè Rosso, Marta ; Cordero, Chiara E. ; Daniel, Hannelore ; Durand, Stéphanie ; Egert, Bjoern ; Ferrario, Paola G. ; Feskens, Edith J.M. ; Franceschi, Pietro ; Garcia-Aloy, Mar ; Giacomoni, Franck ; Giesbertz, Pieter ; González-Domínguez, Raúl ; Hanhineva, Kati ; Hemeryck, Lieselot Y. ; Kopka, Joachim ; Kulling, Sabine E. ; Llorach, Rafael ; Manach, Claudine ; Mattivi, Fulvio ; Migné, Carole ; Münger, Linda H. ; Ott, Beate ; Picone, Gianfranco ; Pimentel, Grégory ; Pujos-Guillot, Estelle ; Riccadonna, Samantha ; Rist, Manuela J. ; Rombouts, Caroline ; Rubert, Josep ; Skurk, Thomas ; Sri Harsha, Pedapati S.C. ; Meulebroek, Lieven Van; Vanhaecke, Lynn ; Vázquez-Fresno, Rosa ; Wishart, David ; Vergères, Guy - \ 2018
Molecular Nutrition & Food Research 63 (2018)1. - ISSN 1613-4125
GC–MS - LC–MS - metabolomics - NMR - nutrition
The life sciences are currently being transformed by an unprecedented wave of developments in molecular analysis, which include important advances in instrumental analysis as well as biocomputing. In light of the central role played by metabolism in nutrition, metabolomics is rapidly being established as a key analytical tool in human nutritional studies. Consequently, an increasing number of nutritionists integrate metabolomics into their study designs. Within this dynamic landscape, the potential of nutritional metabolomics (nutrimetabolomics) to be translated into a science, which can impact on health policies, still needs to be realized. A key element to reach this goal is the ability of the research community to join, to collectively make the best use of the potential offered by nutritional metabolomics. This article, therefore, provides a methodological description of nutritional metabolomics that reflects on the state-of-the-art techniques used in the laboratories of the Food Biomarker Alliance (funded by the European Joint Programming Initiative “A Healthy Diet for a Healthy Life” (JPI HDHL)) as well as points of reflections to harmonize this field. It is not intended to be exhaustive but rather to present a pragmatic guidance on metabolomic methodologies, providing readers with useful “tips and tricks” along the analytical workflow.
Linking phylogenetic identities of bacteria to starch fermentation in an in vitro model of the large intestine by RNA-based stable isotope probing
Kovatcheva-Datchary, P.P. ; Egert, M.G.G. ; Maathuis, A. ; Rajilic-Stojanovic, M. ; Graaf, A.A. de; Smidt, H. ; Vos, W.M. de; Venema, K. - \ 2009
Environmental Microbiology 11 (2009)4. - ISSN 1462-2912 - p. 914 - 926.
chain fatty-acids - 16s ribosomal-rna - length-polymorphism analysis - butyrate-producing bacteria - dietary resistant starch - human fecal bacteria - human feces - human gut - bifidobacterium spp. - molecular analysis
Summary Carbohydrates, including starches, are an important energy source for humans, and are known for their interactions with the microbiota in the digestive tract. Largely, those interactions are thought to promote human health. Using 16S ribosomal RNA (rRNA)-based stable isotope probing (SIP), we identified starch-fermenting bacteria under human colon-like conditions. To the microbiota of the TIM-2 in vitro model of the human colon 7.4 g l(-1) of [U-(13)C]-starch was added. RNA extracted from lumen samples after 0 (control), 2, 4 and 8 h was subjected to density-gradient ultracentrifugation. Terminal-restriction fragment length polymorphism (T-RFLP) fingerprinting and phylogenetic analyses of the labelled and unlabelled 16S rRNA suggested populations related to Ruminococcus bromii, Prevotella spp. and Eubacterium rectale to be involved in starch metabolism. Additionally, 16S rRNA related to that of Bifidobacterium adolescentis was abundant in all analysed fractions. While this might be due to the enrichment of high-GC RNA in high-density fractions, it could also indicate an active role in starch fermentation. Comparison of the T-RFLP fingerprints of experiments performed with labelled and unlabelled starch revealed Ruminococcus bromii as the primary degrader in starch fermentation in the studied model, as it was found to solely predominate in the labelled fractions. LC-MS analyses of the lumen and dialysate samples showed that, for both experiments, starch fermentation primarily yielded acetate, butyrate and propionate. Integration of molecular and metabolite data suggests metabolic cross-feeding in the system, where populations related to Ruminococcus bromii are the primary starch degrader, while those related to Prevotella spp., Bifidobacterium adolescentis and Eubacterium rectale might be further involved in the trophic chain
Administration of Lactobacillus casei and Lactobacillus plantarum affects the diversity of murine intestinal lactobacilli, but not the overall bacterial community structure
Fuentes Enriquez de Salamanca, S. ; Egert, M.G.G. ; Jimenez-Valera, M. ; Ramos-Cormenzana, A. ; Ruiz-Bravo, A. ; Smidt, H. ; Monteoliva-Sanchez, M. - \ 2008
Research in Microbiology 159 (2008)4. - ISSN 0923-2508 - p. 237 - 243.
gradient gel-electrophoresis - 16s ribosomal-rna - genes - identification - microflora - probiotics - reveals - dna
Lactobacilli are normal inhabitants of the gastrointestinal tract (GIT) of many mammalian hosts. Their administration as probiotics in functional foods is currently a frequent practice, mainly because of their benefits to host health. It is therefore of interest to study the impact of administration of exogenous strains of Lactobacillus normally used as probiotics upon endogenous microbial populations. For this purpose, fecal and intestinal tissue samples were analyzed in a mouse model fed with a mixture of Lactobacillus plantarum and Lactobacillus casei isolated from commercially available dairy products. The murine intestinal microbiota was studied by means of cultivation-independent 16S rRNA gene-targeted techniques, namely denaturing gradient gel electrophoresis (DGGE), terminal restriction fragment length polymorphism (T-RFLP) and sequence analysis of clone libraries. Multivariate statistical analysis was used to integrate datasets obtained from the different techniques applied. Whereas no differences were detected in the composition of the overall fecal bacterial community, changes were observed for intestinal tissue samples. Moreover, an increase in the diversity of gut lactobacilli was observed in fecal as well as intestinal tissue samples when mice received the mixture of L. casei and L. plantarum
A strain of Lactobacillus plantarum affects segmented filamentous bacteria in the intestine of immunosupressed mice
Fuentes Enriquez de Salamanca, S. ; Egert, M.G.G. ; Jimenez-Valera, M. ; Monteoliva-Sanchez, M. ; Ruiz-Bravo, A. ; Smidt, H. - \ 2008
FEMS microbiology ecology 63 (2008)1. - ISSN 0168-6496 - p. 65 - 72.
gradient gel-electrophoresis - 16s ribosomal-rna - immunocompromised mice - microbial-populations - immune-system - gut - genes - identification - colonization - arb
Segmented filamentous bacteria (SFB) are present in the gastrointestinal tract of mice from weaning until the maturation of the immune system. Probiotic bacteria also have an effect on host immunity. To study the relationships established between these bacteria, samples from a mouse model fed with Lactobacillus plantarum under different immunological conditions were analysed. SFB populations were measured by a newly designed group-specific quantitative PCR assay. The results confirmed the presence of the probiotic in the intestine and an expansion of SFB in the ileum of immunocompromised mice, which was abolished upon administration of L. plantarum, an effect not described to date.
Identification of glucose-fermenting bacteria present in an in-vitro model of the human inetstine by RNA-stable isotope probing
Egert, M.G.G. ; Graaf, A.A. de; Maathuis, A. ; Waard, P. de; Plugge, C.M. ; Smidt, H. ; Deutz, N.E.P. ; Dijkema, C. ; Vos, W.M. de; Venema, K. - \ 2007
FEMS microbiology ecology 60 (2007)1. - ISSN 0168-6496 - p. 126 - 135.
microbial community structure - fragment-length-polymorphism - chain fatty-acids - propionate oxidation - diversity - pcr - microorganisms - tract - colon - bias
16S rRNA-based stable isotope probing (SIP) and nuclear magnetic resonance (NMR) spectroscopy-based metabolic profiling were used to identify bacteria fermenting glucose under conditions simulating the human intestine. The TIM-2 in vitro model of the human intestine was inoculated with a GI tract microbiota resembling that of the small intestine, to which subsequently 4, 20 or 40 mM of [U-13C]-glucose were added. RNA was extracted from lumen samples after 0 (control), 1, 2 and 4 h and subjected to density-gradient ultracentrifugation. Phylogenetic analysis of unlabeled 16S rRNA revealed a microbial community dominated by lactic acid bacteria and Clostridium perfringens. Distinct 13C-incorporation into bacterial RNA was only observed for the 40-mM addition. 16S rRNA fingerprinting showed an activity drop of Lactobacillus fermentum after glucose addition, while Streptococcus bovis and C. perfringens were identified as the most active glucose-fermenters. Accordingly, NMR analysis identified lactate, acetate, butyrate and formate as the principal fermentation products, constituting up to 91% of the 13C-carbon balance. RNA-SIP combined with metabolic profiling allowed us to detect differential utilization of a general model carbohydrate, indicating that this approach holds great potential to identify bacteria involved in the fermentation of dietary relevant oligo- and polymeric carbohydrates in the human intestine.
Beyond diversity: functional microbiomics of the human colon
Egert, M.G.G. ; Graaf, A. de; Smidt, H. ; Vos, W.M. de; Venema, K. - \ 2006
Trends in Microbiology 14 (2006)2. - ISSN 0966-842X - p. 86 - 91.
chain fatty-acids - human large-intestine - semicontinuous culture system - 16s ribosomal-rna - gut microbiota - gastrointestinal-tract - butyric-acid - amino-acids - fermentation - bacteria
Molecular tools have revealed wide microbial diversity in the human alimentary tract. Most intestinal microorganisms have not been cultured and the in situ functions of distinct groups of the intestinal microbiota are largely unknown but pivotal to understanding the role of these microorganisms in health and disease. Promising strategies to gain more insight into the functionality of the complex microbial communities in the human alimentary tract, including fermentation processes in the colon, are discussed. These research approaches could provide a basis for the definition of a healthy gut based on key properties of microbial functionality. This will also enable the development of direct nutritional strategies for intestinal disease prevention and health promotion
Structure and topology of microbial communities in the major gut compartments of Melolontha melolontha larvae (Coleoptera: Scarabaeidae)
Egert, M.G.G. ; Stingl, U. ; Dyhrberg Bruun, L. ; Pommerenke, B. ; Brune, A. ; Friedrich, M.W. - \ 2005
Applied and Environmental Microbiology 71 (2005)8. - ISSN 0099-2240 - p. 4556 - 4566.
sulfate-reducing bacteria - pachnoda-ephippiata coleoptera - termite mastotermes-darwiniensis - targeted oligonucleotide probes - humus-feeding larva - reticulitermes-flavipes - sp-nov - hindgut - oxygen - hybridization
Physicochemical gut conditions and the composition and topology of the intestinal microbiota in the major gut compartments of the root-feeding larva of the European cockchafer (Melolontha melolontha) were studied. Axial and radial profiles of pH, O2, H2, and redox potential were measured with microsensors. Terminal restriction fragment length polymorphism (T-RFLP) analysis of bacterial 16S rRNA genes in midgut samples of individual larvae revealed a simple but variable and probably nonspecific community structure. In contrast, the T-RFLP profiles of the hindgut samples were more diverse but highly similar, especially in the wall fraction, indicating the presence of a gut-specific community involved in digestion. While high acetate concentrations in the midgut and hindgut (34 and 15 mM) corroborated the presence of microbial fermentation in both compartments, methanogenesis was confined to the hindgut. Methanobrevibacter spp. were the only methanogens detected and were restricted to this compartment. Bacterial 16S rRNA gene clone libraries of the hindgut were dominated by clones related to the Clostridiales. Clones related to the Actinobacteria, Bacillales, Lactobacillales, and -Proteobacteria were restricted to the lumen, whereas clones related to the ß- and -Proteobacteria were found only on the hindgut wall. Results of PCR-based analyses and fluorescence in situ hybridization of whole cells with group-specific oligonucleotide probes documented that Desulfovibrio-related bacteria comprise 10 to 15% of the bacterial community at the hindgut wall. The restriction of the sulfate-reducer-specific adenosine-5'-phosphosulfate reductase gene apsA to DNA extracts of the hindgut wall in larvae from four other populations in Europe suggested that sulfate reducers generally colonize this habitat.
Post-amplification Klenow fragment treatment alleviates PCR bias caused by partially single-stranded amplicons
Egert, M.G.G. ; Friedrich, M.W. - \ 2005
Journal of Microbiological Methods 61 (2005)1. - ISSN 0167-7012 - p. 69 - 75.
microbial community structure - length-polymorphism analysis - ribosomal-rna - genes - heteroduplexes - artifacts - mixtures - cloning
Partially single-stranded amplicons, formed during PCR amplification of single and mixed templates, are a potential source of bias in genetic diversity studies. The analysis of 16S rRNA gene diversity in mixed template samples by the fingerprinting technique terminal restriction fragment length polymorphism (T-RFLP) analysis can be biased by the occurrence of pseudo-T-RFs, i.e., restriction fragments occurring in addition to the expected terminal restriction fragments of single amplicons. This bias originates from PCR products, which are single-stranded at their terminal restriction site. Here we show that treatment of PCR amplicons with Klenow fragment prior to restriction digest and T-RFLP analysis minimized effectively the occurrence of pseudo-T-RFs. Klenow fragment activity filled in bases into the partially single-stranded amplicons and thereby restored the affected amplicons to complete double strands. Our method allowed to improve the assessment of genetic diversity and gene ratios from T-RFLP analysis of an original environmental sample. Since partially single-stranded amplicons might influence many PCR-based techniques, post-amplification treatment with Klenow fragment may be useful for a wide range of applications, which assess the composition of amplicon pools, e.g., the analysis of marker gene diversity in mixed template samples by fingerprinting techniques or the analysis of sequence diversity by cloning.
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