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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    A role for melatonin in maintaining the pro- and anti-inflammatory balance by influencing leukocyte migration and apoptosis in carp
    Kepka, M. ; Szwejser, E. ; Pijanowski, L. ; Verburg-van Kemenade, B.M.L. ; Chadzinska, M.K. - \ 2015
    Developmental and Comparative Immunology 53 (2015). - ISSN 0145-305X - p. 179 - 190.
    coupled receptor dimerization - messenger-rna expression - pineal hormone melatonin - innate immune parameters - common carp - dna-damage - in-vitro - neutrophilic granulocytes - glucocorticoid-receptor - phagocytic-activity
    Melatonin is responsible for the synchronization of many physiological processes, including the immune response. Here we focus on the expression of melatonin MT1 receptors in/on leukocytes, and on the effects of melatonin administration on the inflammatory processes of carp. For the first time, we showed that fish leukocytes express MT1 receptors, implicating direct responsiveness to melatonin stimulation. Moreover, both in vitro and in vivo, melatonin modulated the immune response. The most potent effects of melatonin concerned the regulation of leukocyte migration. Melatonin reduced chemotaxis of leukocytes towards CXC chemokines in vitro. In vivo, during zymosan induced peritonitis, i.p. administration of melatonin reduced the number of neutrophils. This correlated with a melatonin-induced decrease of gene expression of the CXCa chemokine. Moreover, melatonin induced a decrease of the respiratory burst in inflammatory leukocytes. Although these data do suggest a potent anti-inflammatory function for this hormone, melatonin-induced inhibition of leukocyte apoptosis clearly indicates towards a dual function. These results show that also in carp, melatonin performs a pleiotropic and extra-pineal function that is important in maintaining the delicate pro- and anti-inflammatory balance during infection. They furthermore demonstrate that neuroendocrine–immune interaction via melatonin is evolutionary conserved.
    QTL analysis for stomatal functioning in tetraploid Rosa x hybrida grown at high relative air humidity and its implications on postharvest longevity
    Carvalho, D.R.A. ; Koning, C.F.S. ; Fanourakis, D. ; Vasconcelos, M.W. ; Carvalho, S.M.P. ; Heuvelink, E. ; Krens, F.A. ; Maliepaard, C.A. - \ 2015
    Molecular Breeding 35 (2015). - ISSN 1380-3743 - 11 p.
    marker-assisted selection - water relations - cut roses - in-vitro - traits - environments - conductance - sensitivity - improvement - resistance
    High relative air humidity (RH = 85 %) during leaf development disturbs stomatal functioning leading to excessive water loss in conditions of high evaporative demand, resulting in severe reduction in postharvest longevity. In roses, this effect depends on the genotype, opening the possibility for breeding cultivars with more responsive stomata. In this study, we aim at identifying genomic regions associated with the control of water loss following growth at high RH. The F1 generation (108 offspring) and the two parents (P540 and P867) of a tetraploid cut rose population grown at high (85 %) RH were phenotyped for stomatal control to water loss by assessing the relative water content after 4 h of leaflet desiccation (RWC_4 h). The RWC_4 h varied between 7 and 62 % across the 110 studied individuals, with parents P540 and P867 showing 51 and 20 % RWC_4 h, respectively. Based on these data, a quantitative trait locus (QTL) analysis was performed. The impact of the identified QTLs on postharvest longevity of ten selected offspring was further evaluated. Three QTLs were identified: two major [positioned on linkage group 5 of the integrated consensus map (ICM 5) of both parents and on ICM 2 of the parent P867] and one putative minor (mapped to ICM 6 of both parents), explaining 32 % of the variability in the RWC_4 h. Low RWC_4 h was found to be a good proxy for eliminating the offspring with short vase life. This study constitutes a first step toward identifying the most likely regions for genes of interest controlling stomatal functioning in high RH-grown plants.
    Matrix-derived combination effects influencing absorption, distribution, metabolism and excretion (ADME) of food-borne toxic compounds: implications for risk assessment
    Rietjens, I. ; Tyrakowska, B. ; Berg, S.J.P.L. van den; Soffers, A.E.M.F. ; Punt, A. - \ 2015
    Toxicology Research 4 (2015). - ISSN 2045-452X - p. 23 - 35.
    st-johns-wort - dna adduct formation - polycyclic aromatic-hydrocarbons - in-vitro - aflatoxin b-1 - oral bioavailability - gastrointestinal-tract - estragole bioactivation - efflux proteins - tea polyphenols
    Absorption, distribution, metabolism and excretion (ADME) of food-borne toxic compounds may be influenced by other compounds or constituents present in the food. The present review presents an overview of evidence currently available on food matrix-derived combination effects influencing the ADME characteristics of food-borne toxic compounds and the possible implications for risk assessment. The results obtained indicate that interactions may occur at all levels of ADME and that the interactions may decrease but also increase the bioavailability and/or toxicity of the compounds of interest. The overview also illustrates that food matrix-derived combination effects should be considered on a case-by-case basis, taking into account especially the mode of action underlying the interactions and the dose dependency of the effects. Especially food matrix-derived combination effects that proceed by a reversible mode of action, such as for example binding to biotransformation enzymes or transport proteins, may be detected at concentrations used in in vitro assays and at dose levels used in animal bioassays but may be absent at dose levels representing realistic human intake. It is concluded that although food matrix-derived combination effects may exist, their detection in in vitro assays or in animal bioassays at high dose levels may not improve risk assessment practice because interactions observed may not be maintained at low realistic levels of intake. Insight in the mode of action underlying the interactions combined with physiologically based kinetic (PBK) modelling may prove a way to obtain better insight in whether interactions detected at high dose levels will still be relevant at more realistic lower intake levels, and thus to what extent these effects should be taken into account in the risk assessment for human exposure
    Deconjugation of soy isoflavone glucuronides needed for estrogenic activity
    Islam, M.A. ; Bekele, R. ; Berg, J.H.J. van den; Kuswanti, Y. ; Thapa, O. ; Soltani, S. ; Leeuwen, F.X.R. ; Rietjens, I.M.C.M. ; Murk, A.J. - \ 2015
    Toxicology in Vitro 29 (2015)4. - ISSN 0887-2333 - p. 706 - 715.
    beta-messenger-rna - in-vitro - er-beta - receptor-beta - cell-proliferation - human plasma - cancer - expression - alpha - genistein
    Soy isoflavones (SIF) are present in the systemic circulation as conjugated forms of which the estrogenic potency is not yet clear. The present study provides evidence that the major SIF glucuronide metabolites in blood, genistein-7-O-glucuronide (GG) and daidzein-7-O-glucuronide (DG), only become estrogenic after deconjugation. The estrogenic potencies of genistein (Ge), daidzein (Da), GG and DG were determined using stably transfected U2OS-ERa, U2OS-ERß reporter gene cells and proliferation was tested in T47D-ERß cells mimicking the ERa/ERß ratio of healthy breast cells and inT47D breast cancer cells. In all assays applied, the estrogenic potency of the aglycones was significantly higher than that of their corresponding glucuronides. UPLC analysis revealed that in U2OS and T47D cells, 0.2-1.6% of the glucuronides were deconjugated to their corresponding aglycones. The resulting aglycone concentrations can account for the estrogenicity observed upon glucuronide exposure. Interestingly, under similar experimental conditions, rat breast tissue S9 fraction was about 30 times more potent in deconjugating these glucuronides than human breast tissue S9 fraction. Our study confirms that SIF glucuronides are not estrogenic as such, and that the small % of deconjugation in the cell is enough to explain the slight bioactivity observed for the SIF-glucuronides. Species differences in deconjugation capacity should be taken into account when basing risk-benefit assessment of these SIF for the human population on animal data.
    The effect of quercetin and kaempferol aglycones and glucuronides on peroxisome proliferator-activated receptor-gamma (PPAR-¿)
    Beekmann, K. ; Rubió, L. ; Haan, L.H.J. de; Actis Goretta, L. ; Burg, B. van der; Bladeren, P.J. van; Rietjens, I.M.C.M. - \ 2015
    Food & Function 6 (2015)4. - ISSN 2042-6496 - p. 1098 - 1107.
    mitotic clonal expansion - in-vitro - adipocyte differentiation - dietary flavonoids - gene-expression - 3t3-l1 cells - kappa-b - mediated inflammation - cholesterol efflux - molecular target
    The consumption of dietary flavonoids has been associated with a variety of health benefits, including effects mediated by the activation of peroxisome proliferator-activated receptor-gamma (PPAR-¿). Flavonoids are extensively metabolized during and after uptake and there is little known on the biological effects of these conjugated metabolites of flavonoids that are found in plasma. To investigate the effect of glucuronidation on the ability of flavonoids to activate PPAR-¿ we studied and compared the activity of quercetin, kaempferol and their relevant plasma conjugates quercetin-3-O-glucuronide (Q3G) and kaempferol-3-O-glucuronide (K3G) on different PPAR-¿ related endpoints. The flavonoid aglycones increased PPAR-¿ mediated gene expression in a stably transfected reporter gene cell line and glucuronidation diminished their effect. To study the intrinsic activity of the test compounds to activate PPAR-¿ we used a novel microarray technique to study ligand induced ligand binding domain (LBD) – nuclear receptor coregulator interactions. In this cell-free system we demonstrate that, unlike the known PPAR-¿ agonist rosiglitazone, neither the flavonoid aglycones nor the conjugates are agonistic ligands of the receptor. The increases in reporter gene expression in the reporter cells were accompanied by increased PPAR-¿ receptor-mRNA expression and quercetin synergistically increased the effect of rosiglitazone in the reporter gene assay. It is concluded that flavonoids affect PPAR-¿ mediated gene transcription by a mode of action different from agonist binding. Increases in PPAR-¿ receptor mRNA expression and synergistic effects with endogenous PPAR-¿ agonists may play a role in this alternative mode of action. Glucuronidation reduced the activity of the flavonoid aglycones
    Authentication of Geographical Origin and Crop System of Grape Juices by Phenolic Compounds and Antioxidant Activity Using Chemometrics
    Granato, D. ; Koot, A.H. ; Schnitzler, E. ; Ruth, S.M. van - \ 2015
    Journal of Food Science 80 (2015)3. - ISSN 0022-1147 - p. C584 - C593.
    in-vitro - red wines - oxidative stress - fruit juices - rats - capacity - vivo - mechanism - profile
    The main goal of this work was to propose an authentication model based on the phenolic composition and antioxidant and metal chelating capacities of purple grape juices produced in Brazil and Europe in order to assess their typicality. For this purpose, organic, conventional, and biodynamic grape juices produced in Brazil (n = 65) and in Europe (n = 31) were analyzed and different multivariate class-modeling and classification statistical techniques were employed to differentiate juices based on the geographical origin and crop system. Overall, Brazilian juices, regardless of the crop system adopted, presented higher contents of total phenolic compounds and flavonoids, total monomeric anthocyanins, proanthocyanidins, flavonols, flavanols, cyanidin-3-glucoside, delphinidin-3-glucoside, and malvidin-3,5-glucoside. No differences were observed for trans-resveratrol, malvidin-3-glucoside, and pelargonidin-3-glucoside between countries and among crop systems. A total of 91% of Brazilian and 97% of European juices were adroitly classified using partial least squares discriminant analysis when the producing region was considered (92% efficiency), in which the free-radical scavenging activity toward 2,2-diphenyl-1-picrylhydrazyl, content of total phenolic compounds, gallic acid, and malvidin-3-glucoside were the variables responsible for the classification. Intraregional models based on soft independent modeling of class analogy were able to differentiate organic from conventional Brazilian juices as well as conventional and organic/biodynamic European juices.
    Identification of Spodoptera exigua nucleopolyhedrovirus genes involved in pathogenicity and virulence
    Serrano, A. ; Pijlman, G.P. ; Vlak, J.M. ; Muñoz, D. ; Williams, T. ; Caballero, P. - \ 2015
    Journal of Invertebrate Pathology 126 (2015). - ISSN 0022-2011 - p. 43 - 50.
    in-vitro - multiple nucleopolyhedrovirus - myristoylated proteins - baculovirus - sequence - prediction - deletion - finger - genome - vivo
    Genome sequence analysis of seven different Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV) isolates that differed in insecticidal phenotype permitted the identification of genes likely to be involved in pathogenicity of occlusion bodies (OBs) and speed of kill (virulence) of this virus: se4 (hoar), se5 (unknown function), se28 (unknown function), se76 (cg30), se87 (p26) and se129 (p26). To study the role of these genes experimentally on the insecticidal phenotype, a bacmid-based recombination system was constructed to delete selected genes from a SeMNPV isolate, VT-SeAL1, designated as SeBacAL1. All of the knockout viruses were viable and the repair viruses behaved like the wild-type control, vSeBacAL1. Deletion of se4, se5, se76 and se129 resulted in decreased OB pathogenicity compared to vSeBacAL1 OBs. In contrast, deletion of se87 did not significantly affect OB pathogenicity, whereas deletion of se28 resulted in significantly increased OB pathogenicity. Deletion of se4, se28, se76, se87 and se129 did not affect speed of kill compared to the bacmid vSeBacAL1, whereas speed of kill was significantly extended following deletion of se5 and in the wild-type isolate (SeAL1), compared to that of the bacmid. Therefore, biological assays confirmed that several genes had effects on virus insecticidal phenotype. Se5 is an attractive candidate gene for further studies, as it affects both biological parameters of this important biocontrol virus.
    Comprehensive insights into transcriptional adaptation of intracellular mycobacteria by microbe-enriched dual RNA sequencing
    Rienksma, R.A. ; Suarez Diez, M. ; Mollenkopf, H.J. ; Dolganov, G.M. ; Dorhoi, A. ; Schoolnik, G.K. ; Martins Dos Santos, V.A.P. ; Kaufmann, S. ; Schaap, P.J. ; Gengenbacher, M. - \ 2015
    BMC Genomics 16 (2015). - ISSN 1471-2164 - 31 p.
    tuberculosis gene-expression - human macrophage infection - complete genome sequence - cholesterol catabolism - regulated genes - messenger-rna - acyl-coenzyme - in-vitro - host - pathogen
    BackgroundThe human pathogen Mycobacterium tuberculosis has the capacity to escape eradication by professional phagocytes. During infection, M. tuberculosis resists the harsh environment of phagosomes and actively manipulates macrophages and dendritic cells to ensure prolonged intracellular survival. In contrast to other intracellular pathogens, it has remained difficult to capture the transcriptome of mycobacteria during infection due to an unfavorable host-to-pathogen ratio.ResultsWe infected the human macrophage-like cell line THP-1 with the attenuated M. tuberculosis surrogate M. bovis Bacillus Calmette¿Guérin (M. bovis BCG). Mycobacterial RNA was up to 1000-fold underrepresented in total RNA preparations of infected host cells. We employed microbial enrichment combined with specific ribosomal RNA depletion to simultaneously analyze the transcriptional responses of host and pathogen during infection by dual RNA sequencing. Our results confirm that mycobacterial pathways for cholesterol degradation and iron acquisition are upregulated during infection. In addition, genes involved in the methylcitrate cycle, aspartate metabolism and recycling of mycolic acids were induced. In response to M. bovis BCG infection, host cells upregulated de novo cholesterol biosynthesis presumably to compensate for the loss of this metabolite by bacterial catabolism.ConclusionsDual RNA sequencing allows simultaneous capture of the global transcriptome of host and pathogen, during infection. However, mycobacteria remained problematic due to their relatively low number per host cell resulting in an unfavorable bacterium-to-host RNA ratio. Here, we use a strategy that combines enrichment for bacterial transcripts and dual RNA sequencing to provide the most comprehensive transcriptome of intracellular mycobacteria to date. The knowledge acquired into the pathogen and host pathways regulated during infection may contribute to a solid basis for the deployment of novel intervention strategies to tackle infection
    Chemical characterization and biological activity of Chaga (Inonotus obliquus) a medicinal "mushroom"
    Glamoclija, J. ; Ciric, A. ; Nikolic, M. ; Fernandes, A. ; Barros, L. ; Calhelha, R.C. ; Ferreira, I.C.F.R. ; Sokovic, M. ; Griensven, L.J.L.D. van - \ 2015
    Journal of Ethnopharmacology 162 (2015). - ISSN 0378-8741 - p. 323 - 332.
    pseudomonas-aeruginosa - swarming motility - in-vitro - biofilm formation - edible mushrooms - social evolution - aqueous extract - gene-expression - hot-water - antioxidant
    ETHNOPHARMACOLOGICAL RELEVANCE: In Russian traditional medicine, an extract from the mushroom Inonotus obliquus (Fr.) Pil´at is used as an anti-tumor medicine and diuretic. It has been reported that Inonotus obliquus has therapeutic effects, such as anti-inflammatory, immuno-modulatory and hepatoprotective effects. This study was designed to investigate the chemical composition and biological properties of aqueous and ethanolic extracts of Inonotus obliquus from Finland, Russia, and Thailand. Their antioxidative, antimicrobial, and antiquorum properties were tested as well as the cytotoxicity on various tumor cell lines. MATERIALS AND METHODS: The tested extract was subjected to conventional chemical study to identified organic acids and phenolic compounds. Antioxidative activity was measured by several different assays. Antimicrobial potential of extracts was tested by microdilution method, and antiquorum sensing activity and antibiofilm formation of Inonotus obliquus extracts was tested on Pseudomonas aeruginosa. Cytotoxicity of the extracts was tested on tumor cells (MCF-7, NCI-H460, HeLa and HepG2) and non-tumor liver cells primary cultures. RESULTS: Oxalic acid was found as the main organic acid, with the highest amount in the aqueous extract from Russia. Gallic, protocatechuic and p-hydroxybenzoic acids were detected in all samples. Inonotus obliquus extracts showed high antioxidant and antimicrobial activity. Extracts were tested at subMIC for anti-quorum sensing (AQS) activity in Pseudomonas aeruginosa and all extracts showed definite AQS activity. The assays were done using twitching and swarming of bacterial cultures, and the amount of produced pyocyanin as QS parameters. All the extracts demonstrated cytotoxic effect on four tumor cell lines and not on primary porcine liver cells PLP2. CONCLUSIONS: As the Inonotus obliquus presence in Chaga conks is limited, further purification is necessary to draw quantitative conclusions. The presence of AQS activity in medicinal mushrooms suggests a broader anti-infectious disease protection than only immunomodulatory effects.
    Structural bisphenol analoques differentially target steroidogenesis in murine MA-10 Leydig cells as well as the glucocorticoid receptor
    Roelofs, M.J.E. ; Berg, M. van den; Bovee, T.F.H. ; Piersma, A.H. ; Duursen, M.B.M. van - \ 2015
    Toxicology 329 (2015). - ISSN 0300-483X - p. 10 - 20.
    endocrine-disrupting chemicals - tetrabromobisphenol-a tbbpa - brominated flame retardants - one-generation reproduction - in-vitro - fetal testis - exogenous progesterone - gene-expression - risk-assessment - united-states
    Although much information on the endocrine activity of bisphenol A (BPA) is available, a proper human hazard assessment of analogues that are believed to have a less harmful toxicity profile is lacking. Here the possible effects of BPA, bisphenol F (BPF), bisphenol S (BPS), as well as the brominated structural analogue and widely used flame retardant tetrabromobisphenol A (TBBPA) on human glucocorticoid and androgen receptor (GR and AR) activation were assessed. BPA, BPF, and TBBPA showed clear GR and AR antagonism with IC50 values of 67 µM, 60 µM, and 22 nM for GR, and 39 µM, 20 µM, and 982 nM for AR, respectively, whereas BPS did not affect receptor activity. In addition, murine MA-10 Leydig cells exposed to the bisphenol analogues were assessed for changes in secreted steroid hormone levels. Testicular steroidogenesis was altered by all bisphenol analogues tested. TBBPA effects were more directed towards the male end products and induced testosterone synthesis, while BPF and BPS predominantly increased the levels of progestagens that are formed in the beginning of the steroidogenic pathway. The MA-10 Leydig cell assay shows added value over the widely used H295R steroidogenesis assay because of its fetal-like characteristics and specificity for the physiologically more relevant testicular ¿4 steroidogenic pathway. Therefore, adding an in vitro assay covering fetal testicular steroidogenesis, such as the MA-10 cell line, to the panel of tests used to screen potential endocrine disruptors, is highly recommendable.
    Mung Bean: Technological and Nutritional Potential
    Dahiya, P.K. ; Linnemann, A.R. ; Boekel, M.A.J.S. van; Khetarpaul, N. ; Grewal, R.B. ; Nout, M.J.R. - \ 2015
    Critical Reviews in Food Science and Nutrition 55 (2015)5. - ISSN 1040-8398 - p. 670 - 688.
    vigna-radiata l - amino-acid-composition - seed-coat color - var sublobata fabaceae - gram phaseolus-aureus - common indian pulses - l wilczek - green gram - physical-properties - in-vitro
    Mung bean (Vigna radiata (L.) R.Wilczek) has been intensively researched; scattered data are available on various properties. Data on physical, chemical, food processing, and nutritional properties were collected for whole mung bean grains and reviewed to assess the crop’s potential as food and to set research priorities. Results show that mung bean is a rich source of protein (14.6–33.0 g/100 g) and iron (5.9–7.6 mg/100 g). Grain color is correlated with compounds like polyphenols and carotenoids, while grain hardness is associated with fiber content. Physical properties like grain dimensions, sphericity, porosity, bulk, and true density are related to moisture content. Anti-nutrients are phytic acid, tannins, hemagglutinins, and polyphenols. Reported nutrient contents vary greatly, the causes of which are not well understood. Grain size and color have been associated with different regions and were used by plant breeders for selection purposes. Analytical methods require more accuracy and precision to distinguish biological variation from analytical variation. Research on nutrient digestibility, food processing properties, and bioavailability is needed. Furthermore, the effects of storage and processing on nutrients and food processing properties are required to enable optimization of processing steps, for better mung bean food quality and process efficiency.
    Effect of flumorph on F-actin dynamics in the potato late blight pathogen Phytophthora infestans
    Hua, C. ; Kots, K. ; Ketelaar, T. ; Govers, F. ; Meijer, H.J.G. - \ 2015
    Phytopathology 105 (2015)4. - ISSN 0031-949X - p. 419 - 423.
    oomycete aphanomyces-euteiches - plant pathogen - in-vitro - resistance - identification - organization - cytoskeleton - fungicide - proteins - domain
    Oomycetes are fungal-like pathogens that cause notorious diseases. Protecting crops against oomycetes requires regular spraying with chemicals, many of which with unknown mode of action. In the 1990’s, flumorph was identified as a novel crop protection agent. It was shown to inhibit the growth of oomycete pathogens including Phytophthora species, presumably by targeting actin. We recently generated transgenic Phytophthora infestans strains that express Lifeact-eGFP, which enabled us to monitor the actin cytoskeleton during hyphal growth. For analyzing effects of oomicides (8) on the actin cytoskeleton in vivo, the P. infestans Lifeact-eGFP strain is an excellent tool. Here we confirm that flumorph is an oomicide with growth inhibitory activity. Microscopic analyses showed that low flumorph concentrations provoked hyphal tip swellings accompanied by accumulation of actin plaques in the apex, a feature reminiscent of tips of non-growing hyphae. At higher concentrations swelling was more pronounced and accompanied by an increase in hyphal bursting events. However, in hyphae that remained intact, actin filaments were indistinguishable from those in non-treated, non-growing hyphae. In contrast, in hyphae treated with the actin depolymerising drug latrunculin B, no hyphal bursting was observed but the actin filaments were completely disrupted. This difference demonstrates that actin is not the primary target of flumorph.
    Dietary Pectin-Derived Acidic Oligosaccharides Improve the Pulmonary Bacterial Clearance of Pseudomonas aeruginosa Lung Infection in Mice by Modulating Intestinal Microbiota and Immunity
    Bernard, H. ; Desseyn, J.L. ; Bartke, N. ; Kleinjans, L.P.J. ; Belzer, C. ; Knol, J. ; Gottrand, F. ; Husson, M.O. - \ 2015
    The Journal of Infectious Diseases 211 (2015)1. - ISSN 0022-1899 - p. 156 - 165.
    cystic-fibrosis patients - chain fatty-acids - galacto-oligosaccharides - t-cells - cytokine production - virus-infection - human-milk - in-vitro - lactobacillus - butyrate
    Background. A predominantly T-helper type 2 (Th2) immune response is critical in the prognosis of pulmonary Pseudomonas aeruginosa infection. But the mucosal and systemic immune responses can be influenced by the intestinal microbiota. Methods. We assessed the effect of microbiota compositional changes induced by a diet enriched in 5% acidic oligosaccharides derived from pectin (pAOS) on the immune response and outcome of chronic pulmonary P. aeruginosa infection in mice. Results. pAOS promoted Th1 polarization by increasing interferon ¿ release, upregulating t-bet gene expression, decreasing interleukin 4 secretion, and downregulating gata3 gene expression. pAOS also sustained the release of keratinocyte chemoattractant, recruited polynuclear leukocytes and macrophages, stimulated M1 macrophage activation and interleukin 10 release, and decreased tumor necrosis factor a release in the lung. These effects led to increased bacterial clearance after the first and second P. aeruginosa infections. pAOS modified the intestinal microbiota by stimulating the growth of species involved in immunity development, such as Bifidobacterium species, Sutturella wadsworthia, and Clostridium cluster XIVa organisms, and at the same time increased the production of butyrate and propionate. Conclusion. These results suggest that pAOS may have beneficial effects by limiting the number and severity of pulmonary exacerbations in patients chronically infected with P. aeruginosa, such as individuals with cystic fibrosis.
    Assessing the immunomodulatory potential of high-molecular-weight extracts from mushrooms; an assay based on THP-1 macrophages
    Velde, J. van de; Wilbers, R.H.P. ; Westerhof, L.B. ; Raaij, D.R. van; Stavrakaki, I. ; Sonnenberg, A.S.M. ; Bakker, J. ; Schots, A. - \ 2015
    Journal of the Science of Food and Agriculture 95 (2015)2. - ISSN 0022-5142 - p. 344 - 350.
    monocytic leukemia-cells - agaricus-blazei murill - toll-like receptors - in-vitro - induction - responses - line - polysaccharides - differentiation - expression
    BACKGROUND Food is a potential source of immunomodulating compounds that may be used to steer immune responses towards a desired status such as reducing inflammatory disorders. However, to identify and characterize such bioactive compounds, biologically relevant and standardized assays are required. Macrophages play an important role in immunomodulation and are suited for developing cell-based assays. An assay was developed based on macrophages, in a homogeneous differentiation state, using the human monocytic cell line THP-1 previously used to assess immunomodulatory properties of low-molecular-weight allergens, hormones, dietary supplements and therapeutic drugs. RESULTS Zymosan and mushroom polysaccharide extracts lead to a heterogeneous differentiation state of THP-1 monocytes, and these cells secrete low levels of cytokines upon stimulation. Differentiation into macrophages using a low concentration of phorbol 12-myristate 13-acetate improved responsiveness. Elevated levels of cytokines were secreted by cells in a homogenous differentiation state. In addition, it was determined that the assay performs best when using cells at a concentration of (2.5–5)¿×¿105 cells mL-1. CONCLUSION An assay was developed suitable to distinguish the immunomodulatory properties of food compounds in a reproducible manner. It was evaluated using eight mushroom species by measuring the secretion of relevant cytokines TNF-a, IL-1ß, IL-6 and IL-10. © 2014 Society of Chemical Industry
    Toxicity assessment of organomodified clays used in food contact materials on human target cell lines
    Houtman, J. ; Maisanaba, S. ; Puerto, M. ; Gutierrez-Praena, D. ; Jorda, M. ; Aucejo, S. ; Jos, A. - \ 2014
    Applied Clay Science 90 (2014). - ISSN 0169-1317 - p. 150 - 158.
    packaging applications - in-vitro - nanocomposites - montmorillonite - nanomaterials - genotoxicity
    Nowadays, the incorporation of organomodified clays based on montmorillonite into polymers intended for packaging industry is a reality. The final result is a polymer nanocomposite with enhanced barrier properties. Different organomodified clays are already commercially available and others new ones are being developed; however little is known about their safety. In the present work, the cytotoxic effects (a tetrazolium salt reduction and protein content) of three organomodified clays, Cloisite (R) 20A, a commercial clay, and Clay 1 and Clay 2, two novel modified clays developed by the Packaging, Transport, & Logistics Research Institute, were evaluated in Caco-2 and HepG2 cells after 24 and 48 h of exposure. Our results showed that only Clay 2 induced toxic effects in both cell lines. The mean effective concentration was calculated for each case, showing Caco-2 to be more sensitive than HepG2. Moreover, in order to elucidate the toxicity mechanisms of Clay 2, different mechanistic biomarkers were investigated. Interleukin leakage and generation of intracellular reactive oxygen species were not observed, whereas glutathione content decreased in HepG2. DNA damage (comet assay) was induced in both cell lines at the highest concentration tested. Overall, results show that the type of day, the concentrations range and the type of cell line play an important role in the toxicity observed. (C) 2014 Elsevier B.V. All rights reserved.
    Molecular mechanisms underlying the potential antiobesity-related diseases effect of cocoa polyphenols
    Ali, F. ; Ismail, A. ; Kersten, A.H. - \ 2014
    Molecular Nutrition & Food Research 58 (2014)1. - ISSN 1613-4125 - p. 33 - 48.
    low-density-lipoprotein - diet-induced obesity - flavanol-rich cocoa - high-fat diet - nf-kappa-b - ldl oxidative susceptibility - alpha-mediated inflammation - insulin-resistance - dark chocolate - in-vitro
    Obesity and related metabolic diseases (e.g., type 2 diabetes, cardiovascular diseases, and hypertension) are the most prevailing nutrition-related issues in the world. An emerging feature of obesity is their relationship with chronic inflammation that begins in white adipose tissue and eventually becomes systemic. One potential dietary strategy to reduce glucose intolerance and inflammation is consumption of polyphenol-rich cocoa-like cocoa or their by-products. In vitro as well as in vivo data indicate that cocoa polyphenols (CPs) may exhibit antioxidant and anti-inflammatory properties. Polyphenols commonly found in cocoa have been reported to regulate lipid metabolism via inducing metabolic gene expression or activating transcription factors that regulate the expression of numerous genes, many of which play an important role in energy metabolism. Currently, several molecular targets (e.g., nuclear factor Kappa B, activated protein-1, peroxisome proliferator-activated receptors, liver X receptors, and adiponectin gene) have been identified, which may explain potential beneficial obesity-associated diseases effects of CPs. Further studies have been performed regarding the protective effects of CPs against metabolic diseases by suppressing transcription factors that antagonize lipid accumulation. Thus, polyphenols-rich cocoa products may diminish obesity-mediated metabolic diseases by multiple mechanisms, thereby attenuating chronic inflammation.
    in tissue culture of lilium explants may become heavily contaminated by the standard initiation procedure
    Askari Rabori, N. ; Wang, Y.G. ; Klerk, G.J.M. de - \ 2014
    Propagation of ornamental plants 14 (2014)2. - ISSN 1311-9109 - p. 49 - 56.
    sodium-hypochlorite - bud regeneration - cell-cultures - plant-tissue - in-vitro - sterilization - tobacco
    In tissue culture of Lilium, the standard initiation procedure brought about substantial contamination in two ways. (1) When scales were detached from the mother bulb, microorganisms could enter via the wound. This source of contamination was strongly enhanced by the negative hydrostatic pressure within the scales by which nonsterile fluid was sucked up at detachment. Contamination decreased strongly when the scales were detached from bulbs submerged in 0.03% NaClO. Evidence is presented that this type of contamination was endogenous, i.e., localized in the interior of the explant. (2) During the rinsing of scales after surface-sterilization, the rinsing water became contaminated with microorganisms associated with the scales that had not been killed during surface-sterilization. This caused cross-contamination. This type of additional contamination was controlled by rinsing in 0.03% NaClO instead of 'sterile' water. In our conditions, these initiation-related sources of contamination led to ca. 20% and ca. 25% contamination, respectively, of otherwise uninfected scales.
    Cytotoxicity and metabolic stress induced by acetaldehyde in human intestinal LS174T goblet-like cells
    Elamin, E. ; Masclee, A. ; Troost, F. ; Dekker, J. ; Jonkers, D. - \ 2014
    American Journal of Physiology. Gastrointestinal and Liver Physiology 307 (2014)3. - ISSN 0193-1857 - p. G286 - G294.
    mediated endothelial permeability - inflammatory-bowel-disease - in-vitro - epithelial barrier - liver-disease - oral-mucosa - aldehyde dehydrogenases - plasma endotoxin - tight junctions - ethanol
    There is compelling evidence indicating that ethanol and its oxidative metabolite acetaldehyde can disrupt intestinal barrier function. Apart from the tight junctions, mucins secreted by goblet cells provide an effective barrier. Ethanol has been shown to induce goblet cell injury associated with alterations in mucin glycosylation. However, effects of its most injurious metabolite acetaldehyde remain largely unknown. This study aimed to assess short-term effects of acetaldehyde (0, 25, 50, 75, 100 mu M) on functional characteristics of intestinal goblet-like cells (LS174T). Oxidative stress, mitochondrial function, ATP, and intramitochondrial calcium (Ca2+) were assessed by dichlorofluorescein, methyltetrazolium, and bioluminescence, MitoTracker green and rhod-2 double-labeling. Membrane integrity and apoptosis were evaluated by measuring lactate dehydrogenase (LDH), caspase 3/7, and cleavage of cytokeratin 18 (CK18). Expression of mucin 2 (MUC2) was determined by cell-based ELISA. Acetaldehyde significantly increased reactive oxygen species generation and decreased mitochondrial function compared with negative controls (P <0.05). In addition, acetaldehyde dose-dependently decreased ATP levels and induced intramitochondrial Ca2+ accumulation compared with negative controls (P <0.05). Furthermore, acetaldehyde induced LDH release and increased caspase3/7 activity and percentage of cells expressing cleaved CK18 and increased MUC2 protein expression compared with negative controls (P <0.0001). ATP depletion and LDH release could be largely prevented by the antioxidant N-acetylcysteine, suggesting a pivotal role for oxidative stress. Our data demonstrate that acetaldehyde has distinct oxidant-dependent metabolic and cytotoxic effects on LS174T cells that can lead to induction of cellular apoptosis. These effects may contribute to acetaldehyde-induced intestinal barrier dysfunction and subsequently to liver injury.
    Activation of the Epithelial-to-Mesenchymal Transition Factor Snail Mediated Acetaldehyde-Induced Intestinal Epithelial Barrier Disruption
    Elamin, E. ; Masclee, A. ; Troost, F. ; Dekker, J. ; Jonkers, D. - \ 2014
    Alcoholism : Clinical and Experimental Research 38 (2014)2. - ISSN 0145-6008 - p. 344 - 353.
    transcription factor snail - caco-2 cell monolayers - tight junctions - paracellular permeability - in-vitro - adherens junctions - ethanol oxidation - colonic flora - expression - cirrhosis
    Background : Acetaldehyde (AcH) is mutagenic and can reach high concentrations in colonic lumen after ethanol consumption and is associated with intestinal barrier dysfunction and an increased risk of progressive cancers, including colorectal carcinoma. Snail, the transcription factor of epithelial-mesenchymal transition, is known to down-regulate expression of tight junction (TJ) and adherens junction (AJ) proteins, resulting in loss of epithelial integrity, cancer progression, and metastases. As AcH is mutagenic, the role of Snail in the AcH-induced disruption of intestinal epithelial TJs deserves further investigation. Our aim was to investigate the role of oxidative stress and Snail activation in AcH-induced barrier disruption in Caco-2 monolayers. Methods : The monolayers were exposed from the apical side to AcHL-cysteine. Reactive oxygen species (ROS) generation and Snail activation were assessed by ELISA and immunofluorescence. Paracellular permeability, localization, and expression of ZO-1, occludin, E-cadherin, and -catenin were examined using transepithelial electrical resistance (TEER), fluorescein isothiocyanate-labeled dextran 4 kDa (FITC-D4), immunofluorescence, and ELISA, respectively. Involvement of Snail was further addressed by inhibiting Snail using small interfering RNA (siRNA). Results : Exposure to 25M AcH increased ROS generation and ROS-dependently induced Snail phosphorylation. In addition, AcH increased paracellular permeability (decrease in TEER and increase in FITC-D4 permeation) in association with redistribution and decrease of TJ and AJ protein levels, which could be attenuated by L-cysteine. Knockdown of Snail by siRNA attenuated the AcH-induced redistribution and decrease in the TJ and AJ proteins, in association with improvement of the barrier function. Conclusions : Our data demonstrate that oxidative stress-mediated Snail phosphorylation is likely a novel mechanism contributing to the deleterious effects of AcH on the TJ and AJ, and intestinal barrier function.
    A combination of eicosapentaenoic acid-free fatty acid, epigallocatechin-3-gallate and proanthocyanidins has a strong effect on mTOR signaling in colorectal cancer cells
    Angelo, L. D'; Piazzi, G. ; Pacilli, A. ; Prossomariti, A. ; Fazio, C. ; Montanaro, L. ; Graziani, G. ; Fogliano, V. ; Munarini, A. ; Bianchi, F. ; Belluzzi, A. ; Bazzoli, F. ; Ricciardiello, L. - \ 2014
    Carcinogenesis 35 (2014)10. - ISSN 0143-3334 - p. 2314 - 2320.
    activated protein-kinase - colon-cancer - liver metastasis - drug-resistance - carcinoma cells - in-vitro - growth - therapy - inhibition - mutations
    Colorectal cancer (CRC) is one of the major causes of cancer death worldwide. The development of novel anti-CRC agents able to overcome drug resistance and/or off-target toxicity is of pivotal importance. The mammalian target of rapamycin (mTOR) plays a critical role in CRC, regulating protein translation and controlling cell growth, proliferation, metabolism and survival. The aim of this study was to explore the effect of a combination of three natural compounds, eicosapentaenoic acid-free fatty acid (EPA-FFA), epigallocatechin-3-gallate (EGCG) and proanthocyanidins (grape seed [GS] extract) at low cytotoxic concentrations on CRC cells and test their activity on mTOR and translational regulation. The CRC cell lines HCT116 and SW480 were treated for 24 h with combinations of EPA-FFA (0-150 mu M), EGCG (0-175 mu M) and GS extract (0-15 mu M) to evaluate the effect on cell viability. The low cytotoxic combination of EPA-FFA 150 mu M, EGCG 175 mu M and GS extract 15 mu M completely inhibited the mTOR signaling in HCT116 and SW480 cells, reaching an effect stronger than or comparable to that of the mTOR inhibitor Rapamycin in HCT116 or SW480 cells, respectively. Moreover, the treatment led to changes of protein translation of ribosomal proteins, c-Myc and cyclin D1. In addition, we found a reduction of clonal capability in both cell lines, with block of cell cycle in G(0)G(1) and induction of apoptosis. Our data suggest that the low cytotoxic combination of EPA-FFA, EGCG and GS extract, tested for the first time here, inhibits mTOR signaling and thus could be considered for CRC treatment.
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