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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    Production of oat-based synbiotic beverage by two-stage fermentation with Rhizopus oryzae and Lactobacillus acidophilus
    Gao, F. ; Cai, S. ; Nout, M.J.R. ; Wang, Y. ; Xia, Y. ; Li, Y. ; Ji, B. - \ 2012
    Journal of Food, Agriculture & Environment 10 (2012)2. - ISSN 1459-0255 - p. 175 - 179.
    lactic-acid bacteria - beta-glucan - dietary fiber - in-vitro - survival - bifidobacterium - temperature - strains - health - model
    Many studies have reported that oats could effectively reduce the serum cholesterol levels in humans, and the ß-glucan in oat is believed to be responsible for this physiologic effect. Probiotics are live microorganisms that can confer a healthy benefit on the host when administered in adequate amounts. There is an increasing use of these microorganisms in food, aiming to balance intestinal microflora and alleviate dysfunction of the human gastrointestinal tract. However, a number of studies have shown that only 10-30% of these probiotic bacteria could survive after passing through the gastrointestinal (GI) tract. Lactobacillus acidophilus is used as a probiotic bacterium in many probiotic foods. However, L. acidophilus shows poor growth in cereal products due to its poor hydrolytic ability of protein and macromolecule carbohydrates. The aim of the present study was to combine Rhizopus oryzae-fermented oat mash and Lactobacillus acidophilus in an oat-based synbiotic beverage. Several factors, including starter culture concentration, R. oryzae-fermented oat mash and skim milk powder, were investigated. The nutritional contents in R. oryzae-fermented oat flour were just sufficient for survival but not growth of L. acidophilus. Adding sucrose (1% or 2%, w/v) did not improve the proliferation of L. acidophilus; however, L. acidophilus grew quickly when skim milk powder (1% or 2%, w/v) was added. When 5.5% R. oryzae-fermented oat mash with 2% added skim milk powder was used, the viable cell counts reached about 9.0 log cfu/ml at the end of 10 h fermentation. The concentration of ß-glucans (about 781 mg/l) was not significantly lowered during fermentation.
    Bifidobacteria on the spot: a genomics approach on population dynamaics and interactions in the intestinal tract
    Boesten, R.J. - \ 2011
    Wageningen University. Promotor(en): Willem de Vos, co-promotor(en): F.H.J. Schuren. - [S.l. : S.n. - ISBN 9789085858461 - 165
    genexpressieanalyse - bifidobacterium - darmmicro-organismen - genomics - bifidobacterium - intestinal microorganisms
    This thesis combines comprehensive microarray-based studies contributing to a better understanding of the role of bifidobacteria in relation to the human host. It reviews recently described modes of interaction between bifidobacteria and human gastrointestinal cells and highlights the unique characteristics of the genus Bifidobacterium that are indicative for its role in our gut. A microarray platform has been developed that enables genomic comparison of Bifidobacterium species originating from our gastrointestinal tract (GIT). Based on the obtained high-resolution data, species-unique genomic sequences could be identified. A large fraction of these predicted genes encode proteins belonging to the bifidobacterial glycobiome. An unique ability of the microarray platform is to zoom in on the strain level. Direct mapping of genomic hybridization patterns was applied on different B. breve isolates. This revealed a relatively high genomic variation, testifying for the existence of various subspecies within the species B. breve. Clustering of the same hybridization patterns resulted in clear grouping of isolates originating from the same infant, indicating specific niche adaption. Additionally, DNA extracts from Bifidobacterium populations from different infant fecal samples were analyzed. This enabled the analysis of the bifidobacterial population dynamics in breast- and formula-fed infants. The applied microarray platform showed the potential to monitor temporal development and effects of dietary regimens. The observed differences in the composition of bifidobacterial populations could be linked to dietary effects. Additionally, mapping of hybridization patterns enabled monitoring shifts in genomic content within one bifidobacterial species in time. Sequence analysis of DNA fragments showing discriminating hybridization characteristics, resulted in the selection of genes that are either conserved or strain-specific within the species B. breve. Next to studying genomic variation, transcript profiling experiments in both bifidobacterial cells and human intestinal epithelial cell lines were performed. Analysis of bifidobacterial transcriptional responses provided clear proof of transcriptional activity in bifidobacterial cells isolated from infant feces. To the best of our knowledge, this is the first demonstration of in situ activity of bifidobacteria in the human GIT. Furthermore, our results indicate a link between transcription patterns and the infants’ diet, as bifidobacteria in fecal samples from breast-fed infants showed differential transcriptional responses in comparison to those in fecal samples from formula-fed infants. Additionally, transcript sequence analysis revealed expression of genes that are homologous to genes known to be involved in folate production, testifying for the production of this important vitamin in early life. Finally, transcriptome analysis on human intestinal epithelial cells (HIECs) showed species-specific suppression by B. breve M-16V of genes upregulated by TNF-α. Other B. breve strains showed an extreme mild or no effect on TNF-α stimulation. Although we did not observe complete suppression of the TNF effect, we could show that apoptotic and immune regulatory pathways were affected by incubation with cells of B. breve M-16V. In conclusion, the work presented in the thesis, which formed part of a larger IOP Genomics project, contributed to an advanced insight in the interaction between bifidobacteria and the human host. Furthermore, it resulted in the development of genome-based molecular platforms suited for analyzing genomic diversity between and within species, as well as population dynamics in complex microbial communities. We anticipate that the molecular approaches pioneered in this thesis will be instrumental in the further elucidation of the host-microbe interactions in the GIT of human an other animals.
    Exploring the functionality of intestinal Bifidobacteria: a post-genomics approach
    Klaassens, E.S. - \ 2007
    Wageningen University. Promotor(en): Willem de Vos, co-promotor(en): E.E. Vaughan. - [S.l.] : S.n. - ISBN 9789085047148 - 175
    darmmicro-organismen - bifidobacterium - activiteit - zuigelingen - moedermelk - zuigelingenmelk - genexpressieanalyse - intestinal microorganisms - bifidobacterium - activity - infants - human milk - humanized milk - genomics
    Following birth, the human gastrointestinal tract is rapidly colonized by microorganisms that profoundly impact the physiology and health of the host by contributing to host nutrition and natural defense, amongst other activities. In the large intestine, bifidobacteria are especially predominant in infants, where they can comprise up to 90% of the total microbiota, and in adults still account for a significant several percent. In this thesis, we applied post-genomic technologies, including metaproteomics and bifidobacterial community transcript profiling, to deepen our understanding of the activity of commensal bifidobacteria in the human intestine. Proteins were extracted from total infant fecal microbiota that was dominated by bifidobacteria, and two-dimensional gel electrophoresis was used to visualize the metaproteomes. The succession of the proteins was studied in fecal microbiota of two infants during 40 days. This revealed that the number and intensity of protein spots changed in time, but the patterns remained similar and specific for each infant. In-gel digestion of protein-spots and sequencing of the peptides, revealed the presence of a bifidobacterial transaldolase supporting the future application of this approach. Global transcript profiling of the infant fecal bifidobacteria was also performed. Total RNA from the fecal microbiota of infants that were solely breast-fed or formula-fed was hybridized to a DNA microarray comprising clones covering the genomes of several bifidobacterial species. Significantly hybridizing clones were sequenced and compared with those in the public databases. While some sequences were found to be bifidobacterial ribosomal RNA, the majority showed similarity to protein-encoding genes predicted to be involved in carbohydrate metabolism, processing of information and housekeeping functions. Remarkably, significant similarity was observed to an operon involved in the utilization of specifically human milk oligosaccharides and mucin sugars, supporting the functionality of bifidobacteria in the infant intestine. Overall, transcript profiling revealed significant differences between breast-fed and formula-fed infants, which was also reflected in the diversity of fecal bifidobacterial species measured with quantitative real time PCR. In another study, a specific prebiotic mixture showed a shift in the dominant adult fecal microbiota as well as abundance of the different bifidobacterial species. Subsequent transcriptomics using the same bifidobacterial-targeted microarrays showed the activity of genes in a wide range of functional groups, the majority being involved in metabolism of carbohydrates of plant origin, house keeping functions, and membrane transport of a wide variety of substrates including sugars and metals. Furthermore, the transcriptome of Bifidobacterium longum was studied in vitro in human and formula milk and semi-synthetic medium with galactooligosaccharides which showed quite some differentially expressed genes for sugar utilization. Overall, the transcription of genes involved in carbohydrate metabolism and uptake were specifically induced. In conclusion, post-genomics studies of fecal bifidobacteria and batch cultures of B. longum resulted in enhanced understanding of the life style and generated important leads for further investigation of genes for metabolism and colonization of intestinal bifidobacteria within the human host.
    Faecal SIgA secretion in infants fed on pre- or probiotic infant formula
    Bakker-Zierikzee, A. ; Tol, E.A.F. van; Kroes, H. ; Alles, M.S. ; Kok, F.J. ; Bindels, J.G. - \ 2006
    Pediatric Allergy and Immunology 17 (2006)2. - ISSN 0905-6157 - p. 134 - 140.
    lactic-acid bacteria - human-milk - immunity - iga - fructooligosaccharides - bifidobacterium - antibodies - serum - responses - children
    Secretory immunoglobulin A (SIgA) plays an important role in the defence of the gastrointestinal tract. The level of faecal SIgA antibody is associated with increased neutralization and clearance of viruses. Formula-fed infants who lack the transfer of protective maternal SIgA from breast milk may benefit from strategies to support maturation of humoral immunity and endogenous production of SIgA. We aimed at studying the effects of standard, prebiotic and probiotic infant formulas on the faecal SIgA levels. At birth, infants of whom the mother had decided not to breastfeed were allocated to one of three formula groups in a randomized, double-blind fashion. Nineteen infants received standard infant formula; 19 received prebiotic formula containing a specific mixture of 0.6 g galacto-oligosaccharides (GOS)/fructo-oligosaccharides (FOS)/100 ml formula and 19 received probiotic formula containing 6.0 × 109 cfu Bifidobacterium animalis/100 ml formula. Faecal samples were taken on postnatal day 5, day 10, wk 4 and every 4 wk thereafter until wk 32. SIgA in faeces was determined by an enzyme-linked immunosorbent assay. During the intervention, infants fed on prebiotic formula showed a trend towards higher faecal SIgA levels compared with the standard formula-fed infants reaching statistical significance at the age of 16 wk. In contrast, infants fed on the probiotic formula showed a highly variable faecal SIgA concentration with no statistically significant differences compared with the standard formula group. Formula-fed infants may benefit from infant formulas containing a prebiotic mixture of GOS and FOS because of the observed clear tendency to increase faecal SIgA secretion. Adding viable B. animalis strain Bb-12 to infant formula did not reveal any sign for such a trend. Secretory immunoglobulin A (SIgA) is one of the most abundant immunoglobulin in the human body and is the predominant immunoglobulin in mucosal surfaces. SIgA plays a key role in the gastrointestinal defence mechanism against dietary and microbial antigens. It inhibits adherence and invasion of potentially harmful antigens into mucosal tissues and neutralizing toxins and virulence factors from microbial pathogens (1). It is well established that the level of faecal SIgA antibody correlates with higher virus-neutralizing capacity and increased viral clearance (2). IgA deficiency in humans is one of the most common immunodeficiencies and is associated with frequent gastrointestinal infections (3). There is accumulating evidence that the intestinal SIgA production is highly influenced by the intestinal microflora. Indeed, the development of the IgA-producing plasmablasts (intermediate stage of the development of a B-lymphocyte into IgA-producing plasma cell) in the intestinal mucosa seems to be affected by components of the intestinal microflora (4). During the first few weeks after birth, the mucosal humoral immunity is not in a mature state. Passive immunity in this phase is provided by breast milk, which contains high levels of SIgA and antimicrobial peptides. SIgA in breast milk are mainly directed against the mother's previous and current gut microflora (5). Breast milk SIgA protects the maternal mammary gland against mastitis, protects the neonatal mucosa against early exposure to microbes and limits bacterial translocation. In breast milk, SIgA levels are highest during the first days after birth (human colostrum contains 2¿5 mg SIgA/ml) and then gradually decrease to 0.5¿1 mg/ml (6). Although many factors may influence SIgA survival in the large intestine, measuring SIgA levels in faeces gives a good representation of the amount available in the colon (7). In the first 2¿4 wk of life, the concentration of IgA in faeces of breast-fed infants is substantially higher compared to that found in formula-fed infants in whom SIgA is basically undetectable (8). Between 4 wk and 6 months of life, faecal IgA concentrations in both breast-fed and formula-fed infants converge towards similar levels. At age 1¿2 yr, when weaning is completed, the production of SIgA reaches adult levels (9). It is generally recognized that intestinal microflora may play an active role in the ontogeny of the newborn's immune response. Studies performed in germ-free animals showed that colonization leads to the development of the gut-associated lymphoid tissue, including SIgA secretion in the intestine (10, 11). Moreau and Baforiau-Routhiau have shown that in particular bifidobacteria in the infant's intestine are important for the synthesis of IgA against viral enteropathogens. Therefore, they suggested that foods promoting bifidobacteria in the intestine could be instrumental in stimulating endogenous SIgA production and hence promote resistance in infants (12). Although the mechanism of immune stimulation by bifidobacteria is largely unknown, it is thought that the cell walls of Gram-positive bacteria, which are rich in peptidoglycans, may play a role. Both prebiotics and probiotics change the intestinal microflora by increasing the numbers of bifidobacteria and lactobacilli. Bifidobacteria and lactobacilli have various beneficial effects in health and disease, including maintenance of intestinal barrier integrity and mucoprotection, stimulation of protective immune responses and protection against harmful pathogens. During the last decade, interest on the immune effects of probiotics has increased markedly. Experimental studies showed that probiotics have strain-specific effects on immunity, for instance in the prevention or treatment of allergic disease. The reported effects of probiotics include enhancement of gut barrier function and induction of regulatory and pro-inflammatory immune responses (13). Additionally, several studies reported that supplementation of food with prebiotics or probiotics can increase SIgA response to viruses and bacteria. However, most of these studies were performed in animals or in vitro and the mechanisms for this immune stimulation are largely unknown (14¿18). As infants not receiving breast milk have lower SIgA levels during the first months of life, they would potentially benefit from strategies to support maturation and production of mucosal SIgA. Therefore, we studied the effects of infant formula with added probiotics or prebiotics on the faecal SIgA levels in infants. We hypothesized that infants on probiotics or prebiotics will have higher levels of total faecal SIgA compared with infants fed on a standard, unsupplemented infant formula
    Monostrain, multistrain and multispecies probiotics - A comparison of functionality and efficacy
    Timmerman, H.M. ; Koning, C.J.M. ; Mulder, L. ; Rombouts, F.M. ; Beynen, A.C. - \ 2004
    International Journal of Food Microbiology 96 (2004)3. - ISSN 0168-1605 - p. 219 - 233.
    escherichia-coli o157-h7 - lactic-acid bacteria - lactobacillus-acidophilus - streptococcus-thermophilus - salmonella-typhimurium - probiotic bacteria - growth - bifidobacterium - cultures - milk
    This literature review was carried out to make a comparison of functionality and efficacy between monostrain, multistrain and multispecies probiotics. A monostrain probiotic is defined as containing one strain of a certain species and consequently multistrain probiotics contain more than one strain of the same species or, at least of the same genus. Arbitrarily, the term multispecies probiotics is used for preparations containing strains that belong to one or preferentially more genera. Multispecies probiotics were superior in treating antibiotic-associated diarrhea in children. Growth performance and particularly mortality in broilers could be improved with multistrain probiotics. Mice were better protected against S. Typhimurium infection with a multistrain probiotic. A multispecies probiotic provided the best clearance of E. coli O157:H7 from lambs. Rats challenged with S. Enteritidis showed best post-challenge weight gains when treated with a multispecies probiotic. Possible mechanisms underlying the enhanced effects of probiotic mixtures are discussed. It is also emphasized that strains used in multistrain and multispecies probiotics should be compatible or, preferably, synergistic. The design and use of multistrain and multispecies probiotics should be encouraged.
    Molecular identification and characterisation of bifidobacteria and lactobacilli in the human gastrointestinal tract
    Satokari, R. - \ 2002
    Wageningen University. Promotor(en): W.M. de Vos; E.E. Vaughan; M. Saarela. - S.l. : S.n. - ISBN 9789058085634 - 135
    bifidobacterium - lactobacillus - identificatie - spijsverteringsstelsel - polymerase-kettingreactie - elektroforese - bifidobacterium - lactobacillus - identification - digestive system - polymerase chain reaction - electrophoresis

    Bifidobacteria and lactobacilli are considered to be members of the beneficial microbiota in the human gastrointestinal (GI) tract. The present study describes the development and validation of new molecular methods for the detection and analysis of bifidobacteria and lactobacilli and the application of new techniques to study Bifidobacterium and Lactobacillus populations in the human intestine.

    A method based on genus-specific PCR of 16S rDNA and denaturing gradient gel electrophoresis (DGGE) was developed and validated for profiling Bifidobacterium populations in human faeces. The PCR-DGGE method is a qualitative tool for assessing species/strain composition of complex communities by a single PCR reaction and subsequent resolution of the amplification products by DGGE in a sequence-dependent manner. The approach greatly facilitates the monitoring of faecal samples from large numbers of subjects to reveal bifidobacterial diversity and shifts occurring in it. The identification of DGGE fragments can be done by subsequent cloning and sequencing of the PCR products.

    Genotypic methods were developed and evaluated for the identification and characterisation of Lactobacillus casei -group lactobacilli ( L. casei, L. paracasei, L. rhamnosus , and L. zeae ). L. rhamnosus species-specific PCR was developed and validated. The discriminatory power of the three fingerprinting techniques, pulsed field gel electrophoresis (PFGE), randomly amplified polymorphic DNA (RAPD) and ribotyping, was compared. All three techniques were highly effective in differentiating strains below the species level and they can be placed in the following order with respect to their discriminatory power: PFGE > ribotyping > RAPD.

    Newly developed molecular methods were used to trace ingested probiotic strains L. rhamnosus GG (LGG) and B. lactis Bb12 in the GI-tract. The identity of LGG colonies was verified using a species-specific PCR and Bb12 was detected using the PCR-DGGE method. Both probiotic strains colonised the gut transiently and they were no longer detected in the faeces one week after the end of the administration in most subjects. The synbiotic approach with galactooligosaccharide (GOS) did not prolong the persistence of Bb12. Furthermore, LGG was found to attach in vivo to colonic mucosae and, although the attchment was temporary, to remain for more than a week after discontinuation of LGG administration.

    PCR-DGGE method was used to monitor qualitative changes in adult faecal Bifidobacterium populations in response to B. lactis Bb12 and/or GOS administration. In most subjects two weeks administration of Bb12 and/or GOS did not affect the qualitative composition of indigenous bifidobacterial populations, while Bb12 transiently colonised the gut. Qualitative molecular analysis was used to study the bacterial, bifidobacterial and lactobacilli populations in faeces of breast-fed and formula-fed infants before and after weaning. Genus and group-specific PCRs combined with DGGE and subsequent sequencing of the amplified 16S rDNA fragments revealed no difference in the prevalence or species distribution of Bifidobacterium and Lactobacillus between the two groups of infants. In general, DGGE patterns of 16S rDNA showed equal complexity of bacterial communities in breast-fed and formula-fed infants. Equally intensive changes occurred in the faecal microbiota in infants of both groups due to weaning.

    Oligosacchariden als bifidogene factoren.
    Hartemink, R. ; Nout, M.J.R. ; Rombouts, F.M. - \ 1994
    Voedingsmiddelentechnologie 27 (1994)20. - ISSN 0042-7934 - p. 27 - 29.
    bifidobacterium - koolhydraten - chemische reacties - microbiële afbraak - polysacchariden - structuur - carbohydrates - chemical reactions - microbial degradation - polysaccharides - structure
    Levende bacterien die een gunstige invloed hebben op de darmflora. Ze worden probiotica genoemd en ze worden toegepast in zowel de humane voeding als de veevoeding
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