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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    The cashew allergens : a molecular and serological characterization
    Reitsma, Marit - \ 2017
    Wageningen University. Promotor(en): H.J. Wichers; H.F.J. Savelkoul, co-promotor(en): N.W. de Jong. - Wageningen : Wageningen University - ISBN 9789463430784 - 186
    anacardium occidentale - allergens - serological surveys - protein transport - molecular detection - small intestine - pichia pastoris - in vivo experimentation - sds-page - western blotting - electrophoresis - anacardium occidentale - allergenen - serologische overzichten - eiwittransport - moleculaire detectie - dunne darm - pichia pastoris - in vivo experimenten - sds-page - western blotting - elektroforese

    Cashew nut allergy can be a severe food allergy of which the prevalence appears to be increasing. The aim of this thesis was a comprehensive molecular and serological characterisation of the cashew nut allergens Ana o 1, 2 and 3 for improved diagnosis and characterisation of patient populations.

    Chapter 1 in this thesis provides background information on cashew nuts, allergy, the allergens Ana o 1, 2 and 3, the effect of heat treatments on cashew nut proteins, the digestibility of cashew nut proteins, cross-reactivity between cashew nut proteins and other tree nuts, and the detection of cashew nut in food products. Subsequently, in Chapter 2, a review is presented on the topic of epithelial protein and allergen transport. This review describes multiple pathways of intestinal protein transport, sums up existing experimental data concerning protein and peptide transport, and presents different methods to study this. Interestingly, the pathway of (allergenic) protein transport can differ between sensitized and non-sensitized persons. In sensitized persons, protein transport occurs transcellularly via enterocytes, and paracellularly with the involvement of mast cells, while in non-sensitized persons microfold cells and enterocytes are considered most important.

    In the next three chapters, cashew nut allergens were studied. Cashew nut allergy and cashew nut allergens were chosen because of a high number of undiagnosed cashew nut allergic children reported at the children’s hospital “Kinderhaven”, in Rotterdam, an outpatient clinic that is involved in this study. Chapter 3 describes a protocol for the purification of Ana o 1, 2 and 3 from cashew nuts. Ana o 1 and 3 were purified by protein extraction, salt precipitation and filtering over a 30kDa molecular weight membrane. Ana o 2 was purified by protein extraction followed by gel filtration chromatography. These purified proteins were characterised by SDS-PAGE, western blot, glycoprotein stain, and protein identification. In this chapter also more in-depth analysis was performed on the N- and C-termini of the large and small subunits of Ana o 3. These N- and C-termini of Ana o 3, as well as the SDS-PAGE protein profiles were compared between cashew nuts of different origins in Chapter 4. In this chapter also the effects of different heat treatments on the electrophoretic behaviour of cashew nut allergens from various origins were studied, using both 1D and 2D electrophoresis. In these data no significant differences were detected between the electrophoresis patterns of Ana o 1, 2 or 3 in the various origins of cashew nuts. Some small but significant differences in Ana o 1, 2 and 3 content, however, were detected between the differently heated cashew nuts. No major differences in N- and C-terminal micro-heterogeneity were detected between cashew nuts of different origins.

    Next, in Chapter 5, the cashew nut allergens Ana o 1, 2 and 3 were produced as recombinant proteins using a yeast (P. pastoris) production system. This procedure was used as recombinant allergens often produce higher yields of higher purity compared to native purified allergens. The recombinant proteins were compared to the native cashew nut proteins for their glycosylation pattern, IgE binding capacity, and 2D electrophoresis profile. In Chapter 6, the major findings of this thesis are discussed. An overview of the protein characteristics (e.g. 1D and 2D electrophoresis profile, glycosylation, IgE binding, pepsin-digestibility) was provided, as well as a discussion on the clinical benefits that can be derived from the results obtained in this thesis. Also some additional results are presented, studying the serologic cross-reactivity between cashew nuts and other tree nuts and Anacardiaceae nuts and fruits.

    This thesis provides an in-depth study regarding the protein characteristics of the cashew nut allergens Ana o 1, 2 and 3. Using the allergens that were purified in this thesis project, the serum IgE levels of Ana o 1, 2 and 3 could be measured in cashew nut-allergic children. The allergens were also recombinantly produced to obtain higher quantity of allergens for regular use in diagnostics of cashew nut allergy. The results from this thesis can potentially expand clinical patient characterisation with measurements of IgE levels to purified and recombinantly produced major cashew nut allergens. These results might have applications for other food allergens or patient populations.

    Structure of multiresponsive brush-decorated nanoparticles: A combined electrokinetic, DLS, and SANS study
    Martin, J.R.S. ; Bihannic, J. ; Santos, C. ; Farinha, J.P. ; Deme, B. ; Leermakers, F.A.M. ; Pinheiro, J.P. - \ 2015
    Langmuir 31 (2015)16. - ISSN 0743-7463 - p. 4779 - 4790.
    functional-group distributions - soft particles - temperature - water - poly(n-isopropylacrylamide) - electrophoresis - microgels - polymers - core
    Particles consisting of a glassy poly(methyl methacrylate) core (ca. 40 nm in radius) decorated with a poly(N-isopropylacrylamide) anionic corona are synthesized using either methacrylic acid (MA) or acrylic acid (AA) as reactive comonomers in the shell. The different reactivity ratios of MA and AA toward N-isopropylacrylamide originates p(MA-N) and p(N-AA) particles with carboxylate charges supposedly located, preferentially, in the close vicinity of the core and at the shell periphery, respectively. The corresponding swelling features of these nanoparticles are addressed over a broad range of pH values (4 to 7.5), NaNO3 concentrations (3 to 200 mM), and temperatures (15 to 45 °C) by dynamic light scattering (DLS) and small angle neutron scattering (SANS). DLS shows that the swelling of the particle shells increases their thickness from ~10 to 90 nm with decreasing temperature, ionic strength, or increasing pH, with the effect being more pronounced for p(N-AA) whose lower critical solution temperature is shifted to higher values compared to that of p(MA-N). Potentiometric titration and electrokinetic results further reflect the easier dissociation of carboxyl groups in p(N-AA) and a marked heterogeneous interfacial swelling of the latter with decreasing solution salt content. The DLS response of both particles is attributed to the multiresponsive nature of a peripheral dilute shell, while SANS only probes the presence of a quasi-solvent-free dense polymer layer, condensed on the core surface. The thickness of that layer slightly increases from ~6 to 9.5 nm with increasing temperature from 15 to 45 °C (at 15 mM NaNO3 and pH 5) due to the collapse of the outer dilute shell layer. Overall, results evidence a nonideal brush behavior of p(MA-N) and p(N-AA) and their microphase segregated shell structure, which supports some of the conclusions recently formulated from approximate self-consistent mean-field computations.
    Factors influencing casein micelle size in milk of individual cows: Genetic variants and glycosylation of k-casein
    Bijl, E. ; Vries, R.F.M. de; Valenberg, H.J.F. van; Huppertz, T. ; Hooijdonk, A.C.M. van - \ 2014
    International Dairy Journal 34 (2014)1. - ISSN 0958-6946 - p. 135 - 141.
    protein-composition - bovine-milk - liquid-chromatography - electrophoresis - polymorphism - coagulation - genotypes - pattern - cattle
    The average casein micelle size varies widely between milk samples of individual cows. The factors that cause this variation in size are not known but could provide more insight into casein micelle structure and into the physiology of casein micelle formation. The objective of this research was therefore to determine factors that influence average casein micelle size in milk from individual cows. Average casein micelle size of milk samples was associated with the A and B genetic variants of k-casein, and differences in concentration of glycosylated k-casein as a fraction of total milk protein. Milk samples with a low average casein micelle size were associated with the B variant of k-casein and a higher relative concentration of glycosylated k-casein, compared with milk samples with a high average casein micelle size. Differences observed may be attributed to the effect of glycosylated k-casein groups on casein micelle formation in the mammary gland.
    A modified rinsing method for the determination of the S, W-S and D + U fraction of protein and starch in feedstuff within the in situ technique
    Jonge, L.H. de; Laar, H. van; Hendriks, W.H. ; Dijkstra, J. - \ 2013
    Animal 7 (2013)8. - ISSN 1751-7311 - p. 1289 - 1297.
    rumen - degradability - degradation - electrophoresis - ruminants - profiles - extent - sacco
    A modified rinsing method for the in situ technique was developed to separate, isolate and characterise the soluble (S), the insoluble washout (W–S) and the non-washout fractions (D1U) within one procedure. For non-incubated bags ( t50 h), this method was compared with the conventional, Combined Fractionation (CF) method that measures the D1U and S fractions in separate steps and subsequently calculates the W–S fraction. The modified method was based on rinsing of nylon bags in a closed vessel containing a buffer solution (pH 6.2) during 1 h, where shaking speeds of 40, 100, and 160 strokes per minutes (spm) were evaluated, and tested for six feed ingredients (faba beans, maize, oats, peas, soya beans and wheat) and four forages (two ryegrass silages and two maize silages). The average recoveries as the sum of all fractions were 0.97260.041 for N and 0.99060.050 for starch (mean6s.d.). The mean W–S fraction increased with increasing shaking speed and varied between 0.017 (N) and 0.083 (starch) at 40 spm and 0.078 (N) and 0.303 (starch) at 160 spm, respectively. For ryegrass silages, the W–S fraction was absent at all shaking speeds, but was present in the CF method. The modified method, in particular at 40 and 100 spm, reduced the loss of small particles during rinsing, resulting in lower W–S and higher D1U fractions for N and starch compared with the CF method. For soya beans and ryegrass silage, the modified method reduced the S fraction of N compared with the CF method. The results obtained at 160 spm showed the best comparison with those from the CF method. The W–S fraction of the feedstuff obtained at 160 spm contained mainly particles smaller than 40 mm (0.90860.086). In most feedstuff, starch was the most abundant chemical component in the W–S fraction and its content (726675 g/kg DM) was higher than in the D1U fraction (4056177 g/kg DM). Alkaline-soluble proteins were the dominant N-containing components in the W–S fraction of dry feed ingredients and its relative content (0.7960.18 of total N in W–S) was higher than in the D1U fraction (0.5960.07 of total N in D1U) for all feedstuff except maize. The molecular weight distribution of the alkaline-soluble proteins differed between the W–S and the D1U fractions of all dry feed ingredients, except soya beans and wheat.
    Characterization of low-molecular-weight-glutenin subunit genes from the D-genome of Triticum aestivum, Aegilops crassa, Ae. cylindrica and Ae. tauschii
    Naghavi, M.R. ; Ahmadi, S. ; Shanejat-Boushehri, A.A. ; Komaei, G. ; Struik, P.C. - \ 2013
    Biochemical Systematics and Ecology 50 (2013). - ISSN 0305-1978 - p. 23 - 29.
    endosperm storage proteins - group-1 chromosomes - wheat endosperm - hexaploid wheat - common wheat - cloning - pcr - electrophoresis - identification - polymorphism
    Twenty low-molecular-weight-glutenin subunit (LMW-GS) gene sequences from the D-genome from Aegilops crassa (2n ¼ 4x ¼ 28), Ae. cylindrica (2n ¼ 4x ¼ 28), Ae. tauschii (2n ¼ 2x ¼ 14) and Triticum aestivum (2n ¼ 6x ¼ 42) were obtained using five sets of specific allele primer pairs. Only the sequences of the first primer pair were complete coding sequences (cds) of LMW-GS, and had 305, 304, 306 and 305 LMW-m amino acid residues in Ae. crassa, Ae. cylindrica, Ae. tauschii and T. aestivum, respectively. The repetitive domain and repeat motif numbers of all LMW glutenin subunits showed eight conserved cysteine residues that lead to the same functional activity in different genome. Based on DNA and predicted protein sequences, phylogenetic trees for all sets of sequences were drawn. At the DNA level, the species closest to T. aestivum for the second, third, fourth and fifth set of sequences were Ae. cylindrica, Ae. tauschii and Ae. crassa, respectively. At the protein level, the species closest to T. aestivum based on the first, second and fifth set of sequences were Ae. cylindrica, Ae. crassa and Ae. crassa, respectively. For other sets of sequences, bread wheat proved to be a distinct species. The LMW-GS gene sequences have been recorded in the GenBank with accession numbers JQ726549–JQ726568.
    A quantitative approach towards a better understanding of the dynamics of Salmonella spp. in a pork slaughter-line
    Hoek, A.H.A.M. van; Jonge, R. de; Overbeek, W.M. van; Bouw, E.M. ; Pielaat, A. ; Smid, J.H. ; Malorny, B. ; Junker, E. ; Lofstrom, C. ; Pedersen, K. ; Aarts, H.J.M. ; Heres, L. - \ 2012
    International Journal of Food Microbiology 153 (2012)1-2. - ISSN 0168-1605 - p. 45 - 52.
    enterica serovar typhimurium - cross-contamination - carcasses - prevalence - excision - pigs - electrophoresis - identification - abattoirs - gauze
    Pork contributes significantly to the public health disease burden caused by Salmonella infections. During the slaughter process pig carcasses can become contaminated with Salmonella. Contamination at the slaughter-line is initiated by pigs carrying Salmonella on their skin or in their faeces. Another contamination route could be resident flora present on the slaughter equipment. To unravel the contribution of these two potential sources of Salmonella a quantitative study was conducted. Process equipment (belly openers and carcass splitters), faeces and carcasses (skin and cutting surfaces) along the slaughter-line were sampled at 11 sampling days spanning a period of 4 months. Most samples taken directly after killing were positive for Salmonella. On 96.6% of the skin samples Salmonella was identified, whereas a lower number of animals tested positive in their rectum (62.5%). The prevalence of Salmonella clearly declined on the carcasses at the re-work station, either on the cut section or on the skin of the carcass or both (35.9%). Throughout the sampling period of the slaughter-line the total number of Salmonella per animal was almost 2log lower at the re-work station in comparison to directly after slaughter. Seven different serovars were identified during the study with S. Derby (41%) and S. Typhimurium (29%) as the most prominent types. A recurring S. Rissen contamination of one of the carcass splitters indicated the presence of an endemic 'house flora' in the slaughterhouse studied. On many instances several serotypes per individual sample were found. The enumeration of Salmonella and the genotyping data gave unique insight in the dynamics of transmission of this pathogen in a slaughter-line. The data of the presented study support the hypothesis that resident flora on slaughter equipment was a relevant source for contamination of pork.
    Cultivation of hitherto-uncultured bacteria belonging to the Verrucomicrobia subdivision 1 from the potato (Solanum tuberosum L.) rhizosphere
    Rocha, U.N. da; Andreote, F.D. ; Azevedo, J.L. ; Elsas, J.D. van; Overbeek, L.S. van - \ 2010
    Journal of Soils and Sediments 10 (2010)2. - ISSN 1439-0108 - p. 326 - 339.
    16s ribosomal-rna - soil bacteria - community structure - sequence data - pure culture - diversity - culturability - growth - genes - electrophoresis
    The role of dominant bacterial groups in the plant rhizosphere, e.g., those belonging to the phyla Acidobacteria and Verrucomicrobia, has, so far, not been elucidated, and this is mainly due to the lack of culturable representatives. This study aimed to isolate hitherto-uncultured bacteria from the potato rhizosphere by a combination of cultivation approaches. An agar medium low in carbon availability (oligotrophic agar medium) and either amended with potato root exudates or catalase or left unamended was used with the aim to improve the culturability of bacteria from the potato rhizosphere. The colony forming unit numbers based on colonies and microcolonies were compared with microscopically determined fluorescence-stained cell numbers. Taxonomical diversity of the colonies was compared with that of library clones made from rhizosphere DNA, on the basis of 16S rRNA gene comparisons. The oligotrophic media amended or not with catalase or rhizosphere extract recovered up to 33.6% of the total bacterial numbers, at least seven times more than the recovery observed on R2A. Four hitherto-uncultured Verrucomicrobia subdivision 1 representatives were recovered on agar, but representatives of this group were not found in the clone library. The use of oligotrophic medium and its modifications enabled the growth of colony numbers, exceeding those on classical agar media. Also, it led to the isolation of hitherto-uncultured bacteria from the potato rhizosphere. Further improvement in cultivation will certainly result in the recovery of other as-yet-unexplored bacteria from the rhizosphere, making these groups accessible for further investigation, e.g., with respect to their possible interactions with plants.
    Population diversity of Listeria monocytogenes LO28: phenotypic and genotypic characterization of variants resistant to high hydrostatic pressure
    Boeijen, K.H. van; Chavaroche, A.A.E. ; Valderrama, W.B. ; Moezelaar, R. ; Zwietering, M.H. ; Abee, T. - \ 2010
    Applied and Environmental Microbiology 76 (2010)7. - ISSN 0099-2240 - p. 2225 - 2233.
    processing plant - ctsr - inactivation - contamination - persistent - tolerance - virulence - stress - scott - electrophoresis
    A comparative phenotype analysis of 24 Listeria monocytogenes LO28 stress-resistant variants obtained after high-pressure treatment was performed to assess their robustness and growth performance under a range of food-relevant conditions. In addition, genetic analysis was conducted to characterize the promoter regions and open reading frames of the class I and III transcriptional repressors CtsR and HrcA, which control production of specific sets of stress proteins. Analysis of stress survival capacity, motility, biofilm formation, and growth under various conditions showed all variants to be more resistant to pressure and heat than the wild type; however, differences among variants were observed in acid resistance, growth rate, motility, and biofilm-forming capacity. Genetic analysis revealed no variation in the genetic make-up of hrcA and its upstream region, but two variants had deletions in the upstream region of ctsR and seven variants had mutations in the ctsR gene itself. The results of the characterization were cluster analyzed to obtain insight into the diversity of variants. Ten unique variants and three clusters with specific features could be identified: one cluster consisting of seven variants having a mutation in the CtsR regulator gene, one cluster containing two variants with an aerobic biofilm formation capacity similar to that of the wild type, and a cluster composed of five immotile variants. The large population diversity of L. monocytogenes stress-resistant variants signifies the organism's genetic flexibility, which in turn may contribute to the survival and persistence of this human pathogen in food-processing environments.
    Selective recovery of nickel over iron from a nickel-iron solution using microbial sulfate reduction in a gas-lift bioreactor
    Bijmans, M.F.M. ; Helvoort, P.J. van; Dar, S. ; Dopson, M. ; Lens, P.N.L. ; Buisman, C.J.N. - \ 2009
    Water Research 43 (2009)3. - ISSN 0043-1354 - p. 853 - 861.
    mijnbouw - metallurgie - mijnafval - slib - waterstof - ijzer - nikkel - bioreactoren - elektroforese - sulfaatreductie - slibzuivering - verwijdering - mining - metallurgy - mine tailings - sludges - hydrogen - iron - nickel - bioreactors - electrophoresis - sulfate reduction - sludge treatment - removal - gradient gel-electrophoresis - sulfide precipitation - metal precipitation - heavy-metals - soils - water - ores
    Process streams with high concentrations of metals and sulfate are characteristic for the mining and metallurgical industries. This study aims to selectively recover nickel from a nickel-iron-containing solution at pH 5.0 using a single stage bioreactor that simultaneously combines low pH sulfate reduction and metal-sulfide formation. The results show that nickel was selectively precipitated in the bioreactor at pH 5.0 and the precipitates consisted of >or=83% of the nickel content. The nickel-iron precipitates were partly crystalline and had a metal/sulfur ratio of 1, suggesting these precipitates were NiS and FeS. Experiments focusing on nickel recovery at pH 5.0 and 5.5 reached a recovery of >99.9%, resulting in a nickel effluent concentration
    Arabinogalactan Proteins Are Incorporated in Negatively Charged Coffee Brew Melanoidins
    Bekedam, E.K. ; Laat, M.P.F.C. de; Schols, H.A. ; Boekel, M.A.J.S. van; Smit, G. - \ 2007
    Journal of Agricultural and Food Chemistry 55 (2007)3. - ISSN 0021-8561 - p. 761 - 768.
    arabica beans - maillard reaction - espresso coffee - green - model - food - polysaccharides - electrophoresis - substances - components
    The charge properties of melanoidins in high molecular weight (HMw) coffee brew fractions, isolated by diafiltration and membrane dialysis, were studied. Ion exchange chromatography experiments with the HMw fractions showed that coffee brew melanoidins were negatively charged whereas these molecules did not expose any positive charge at the pH of coffee brew. Fractions with different ionic charges were isolated and subsequently characterized by means of the specific extinction coefficient (Kmix 405nm), sugar composition, phenolic group content, nitrogen content, and the arabinogalactan protein (AGP) specific Yariv gel-diffusion assay. The isolated fractions were different in composition and AGP was found to be present in one of the HMw fractions. The AGP accounted for 6% of the coffee brew dry matter and had a moderate negative charge, probably caused by the presence of uronic acids. As the fraction that precipitated with Yariv was brown (Kmix 405nm = 1.2), compared to a white color in the green bean, it was concluded that these AGPs had undergone Maillard reaction resulting in an AGP-melanoidin complex. The presence of mannose (presumably from galactomannan) indicates the incorporation of galactomannans in the AGP-melanoidin complex. As the uronic acid content in the more negatively charged melanoidin-rich, AGP-poor HMw fractions decreased, it was hypothesized that acidic groups are formed or incorporated during melanoidin formation.
    Image analysis, methanogenic activity measurements, and molecular biological techniques to monitor granular sludge from EGSB reactors fed with oleic acid
    Pereira, M.A. ; Roest, K. de; Stams, A.J.M. ; Akkermans, A.D.L. ; Amaral, A.L. ; Pons, M.N. ; Ferreira, E.C. ; Mota, M. ; Alves, M. - \ 2003
    Water Science and Technology 47 (2003). - ISSN 0273-1223 - p. 181 - 188.
    slib - oleïnezuur - korrels - afbeelden - methaan - elektroforese - microbiële afbraak - afvalwaterbehandeling - sludges - oleic acid - granules - imagery - methane - electrophoresis - microbial degradation - waste water treatment - gradient gel-electrophoresis - diversity - bacteria - biodegradability - identification - toxicity - dna
    Morphological changes in anaerobic granular sludge fed with increasing loads of oleic acid were quantified by image analysis. The combination of this technique with data on-the accumulation of adsorbed long chain fatty acid and with the molecular characterization of microbial community gave insight into the mechanisms of sludge disintegration, flotation and washout
    Morphological changes in anaerobic granular sludge fed with increasing loads of oleic acid were quantified by image analysis. The combination of this technique with data on-the accumulation of adsorbed long chain fatty acid and with the molecular characterization of microbial community gave insight into the mechanisms of sludge disintegration, flotation and washout. It was found that the bacterial domain was more affected than the archaeal domain during this process. However, no acetoclastic activity and only a residual hydrogenotrophic activity were detected in the sludge at the end of the operation.
    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.

    Electrodialysis system for large-scale enantiomer separation
    Ent, E.M. van der; Thielen, T.P.H. ; Cohen Stuart, M.A. ; Padt, A. van der; Keurentjes, J.T.F. - \ 2001
    Industrial & Engineering Chemistry Research 40 (2001). - ISSN 0888-5885 - p. 6021 - 6027.
    beta-cyclodextrin - chiral recognition - racemic mixtures - amino-acids - electrophoresis - thermodynamics - membranes - ultrafiltration - complexation - resolution
    In contrast to analytical methods, the range of technologies currently applied for large-scale enantiomer separations is not very extensive. Therefore, a new system has been developed for large-scale enantiomer separations that can be regarded as the scale-up of a capillary electrophoresis system. In this stacked membrane system, chiral selectors that are retained by size-selective membranes are used. Upon application of an electrical potential, selective transport of the free enantiomer will occur, thus providing separation. In principle, this system can handle the same extensive range of enantiomers that can be separated in capillary electrophoresis systems on an analytical scale. In a system containing four separation compartments, alpha -cyclodextrin has been used as a chiral selector to separate D,L-Trp. Based on a transport model, a factorial design is used to investigate the effects of various process parameters. The results show that the addition of methanol is of minor influence, whereas the pH has a major effect, both on the operational selectivity and on the transport number. Experiments with AgNO3 as the background electrolyte showed that the operational selectivity has a plateau value of 1.08 at a pH ranging from 3 to 6. Because of the ease of scale-up of electrodialysis processes, this operational selectivity will allow for the separation of enantiomers on a large scale.
    Elektroforetische identificatie en detectie van plantpathogene organismen
    Rijn, C. van; Kerssies, A. - \ 1996
    Aalsmeer : Proefstation voor Bloemisterij en Glasgroente (Rapport / Proefstation voor Bloemisterij en Glasgroente 29) - 36
    plantenziekteverwekkers - identificatie - elektroforese - phytophthora - gnomonia - cylindrocladium - nederland - fusarium oxysporum f.sp. cyclaminis - fusarium oxysporum f.sp. gladioli - plant pathogens - identification - electrophoresis - phytophthora - gnomonia - cylindrocladium - netherlands - fusarium oxysporum f.sp. cyclaminis - fusarium oxysporum f.sp. gladioli
    Reiniging van dunne meststromen door middel van elektrodialyse
    Gastel, J. van; Vrielink, M. - \ 1996
    Praktijkonderzoek varkenshouderij 10 (1996)1. - ISSN 1382-0346 - p. 20 - 22.
    rundveedrijfmest - schoonmaken - desinfectie - elektrodialyse - elektroforese - filters - filtratie - industrie - vloeibare meststoffen - mest - varkens - elektrochemie - mestoverschotten - mestverwerking - cattle slurry - cleaning - disinfection - electrodialysis - electrophoresis - filters - filtration - industry - liquid manures - manures - pigs - electrochemistry - manure surpluses - manure treatment
    Het Praktijkonderzoek Varkenshouderij onderzocht in samenwerking met Tauw Milieu bv in Deventer de mogelijkheden voor reiniging van dunne meststromen door middel van elektrodialyse. Reiniging tot de lozingsnormen voor het riool lijkt haalbaar. De kosten voor het proces op boerderijschaal zijn echter vooralsnog te hoog.
    Identificatie van anjerrassen met behulp van elektroforese
    Schoot, J. van der - \ 1994
    Wageningen : CPRO-DLO (Intern rapport / CPRO-DLO ) - 15
    rassen (planten) - cultivars - rassen (taxonomisch) - sierplanten - caryophyllaceae - elektroforese - varieties - races - ornamental plants - electrophoresis
    Ontwikkeling van een detectiemethode voor Fusarium oxysporum f.sp. cyclaminis en dianthi gebaseerd op polyacrylamidegel - elektroforese
    Everink, J.T. - \ 1992
    Aalsmeer : Proefstation voor de Bloemisterij (Rapport / Proefstation voor de Bloemisterij 142) - 34
    fusarium oxysporum f.sp. dianthi - detectie - page - elektroforese - fusarium oxysporum f.sp. cyclaminis - fusarium oxysporum f.sp. dianthi - detection - page - electrophoresis - fusarium oxysporum f.sp. cyclaminis
    Optimalisering elektroforesemethode van aardappel ten behoeve van geautomatiseerde identificatie : intern rapport CPRO-DLO
    Schoot, J. van der; Wouters, T.C.A.E. - \ 1992
    Wageningen : CPRO-DLO - 18
    cultivars - descriptoren - elektroforese - identificatie - aardappelen - rassen (taxonomisch) - solanum tuberosum - rassen (planten) - descriptors - electrophoresis - identification - potatoes - races - varieties
    Identificatie van tulperassen met behulp van elektroforese
    Schoot, H. van der - \ 1991
    Wageningen : CPRO-DLO - 14
    cultivars - elektroforese - identificatie - liliaceae - bloembollen - rassen (taxonomisch) - rassen (planten) - tulipa - electrophoresis - identification - ornamental bulbs - races - varieties
    Vergelijkend onderzoek naar de toepasbaarheid van de Nieuwe Nederlandse Niertest voor het aantonen van bacteriegroeiremmende stoffen in nieren van slachtdieren
    Nouws, J.F.M. ; Broex, N.J.G. ; Hartog, J.M.P. den - \ 1986
    Wageningen : RIKILT (Rapport / RIKILT 86.92) - 19
    vleeskeuring - nieren - slachtdieren - residuen - elektroforese - meat inspection - kidneys - meat animals - residues - electrophoresis
    Door vier R.V.V. kringlaboratoria zijn integraal nieren van slachtdieren (noodslachtingen en 1/2%-onderzoek) onderzocht op het voorkomen van bacteriegroeirenm1ende stoffen . Van een aantal als positief beoordeelde nieren (wettelijke test remming >15 mm; nieuwe Nederlandse niertest remming >20 mm), is de bacteriegroeiremmende stof geidentificeerd met behulp van hoogspanningselektroforese. Gedurende het onderzoek is een kwaliteitscontrole-systeem met behulp van standaard controleschijfjes geintroduceerd . De reproduceerbaarheld van het resultaat van de N.N.N.T. werd nagegaan met simultaan geimpregneerde papierschijfjes, welke gedurende 1 week bij -25°C waren bewaard en met de gedurende 2 x 24 uren gekoelde karkasnier.
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