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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    Oral administration of Lactobacillus plantarum 299v modulates gene expression in the ileum of pigs: prediction of crosstalk between intestinal immune cells and sub-mucosal adipocytes
    Hulst, M.M. ; Gross, G. ; Liu, Yapin ; Hoekman, A.J.W. ; Niewold, T. ; Meulen, J. van der; Smits, M.A. - \ 2015
    Genes & Nutrition 10 (2015)3. - ISSN 1555-8932 - 13 p.
    kappa-b - functional-analysis - in-vivo - inhibition - immunoglobulins - identification - adipogenesis - macrophages - metabolism - activation
    To study host–probiotic interactions in parts of the intestine only accessible in humans by surgery (jejunum, ileum and colon), pigs were used as model for humans. Groups of eight 6-week-old pigs were repeatedly orally administered with 5 × 1012 CFU Lactobacillus plantarum 299v (L. plantarum 299v) or PBS, starting with a single dose followed by three consecutive daily dosings 10 days later. Gene expression was assessed with pooled RNA samples isolated from jejunum, ileum and colon scrapings of the eight pigs per group using Affymetrix porcine microarrays. Comparison of gene expression profiles recorded from L. plantarum 299v-treated pigs with PBS-treated pigs indicated that L. plantarum 299v affected metabolic and immunological processes, particularly in the ileum. A higher expression level of several B cell-specific transcription factors/regulators was observed, suggesting that an influx of B cells from the periphery to the ileum and/or the proliferation of progenitor B cells to IgA-committed plasma cells in the Peyer’s patches of the ileum was stimulated. Genes coding for enzymes that metabolize leukotriene B4, 1,25-dihydroxyvitamin D3 and steroids were regulated in the ileum. Bioinformatics analysis predicted that these metabolites may play a role in the crosstalk between intestinal immune cells and sub-mucosal adipocytes. Together with regulation of genes that repress NFKB- and PPARG-mediated transcription, this crosstalk may contribute to tempering of inflammatory reactions. Furthermore, the enzyme adenosine deaminase, responsible for the breakdown of the anti-inflammatory mediator adenosine, was strongly down-regulated in response to L. plantarum 299v. This suggested that L. plantarum 299v-regulated production of adenosine by immune cells like regulatory T cells may also be a mechanism that tempers inflammation in the ileum, and perhaps also in other parts of the pig’s body.
    Influence of phenylacetic acid pulses on anaerobic digestion performance and archaeal community structure in WWTP sewage sludge digesters
    Cabrol, L. ; Urra, J. ; Rosenkranz, F. ; Kroff, P.A. ; Plugge, C.M. ; Lesty, Y. ; Chamy, R. - \ 2015
    Water Science and Technology 71 (2015)12. - ISSN 0273-1223 - p. 1790 - 1799.
    rioolslib - anaërobe behandeling - anaërobe afbraak - sewage sludge - anaerobic treatment - anaerobic digestion - waste-water treatment - olive mill wastewaters - volatile fatty-acids - 16s ribosomal-rna - biogas production - degradation efficiency - microbial-populations - aromatic-compounds - phenolic-compounds - inhibition
    The effect of phenylacetic acid (PAA) pulses on anaerobic digestion (AD) performance and archaeal community structure was evaluated in anaerobic digesters treating sewage sludge from a wastewater treatment plant (WWTP). Four pilot-scale continuous stirred tank reactors were set up at a full-scale municipal WWTP in Santiago de Chile, and fed with either primary or mixed sewage sludge. AD performance was evaluated by volatile fatty acid (VFA) and biogas production monitoring. Archaeal community structure was characterized by 16S rRNA denaturing gradient gel electrophoresis and band sequencing. In the primary sludge digester, a single PAA pulse at 200 mg L(-1) was sufficient to affect AD performance and archaeal community structure, resulting in long-term VFA accumulation, reduced biogas production and community shift from dominant acetoclastic (Methanosaeta concilii) to hydrogenotrophic (Methanospirillum hungatei) methanogens. By contrast, AD performance and archaeal community structure in the mixed sludge digester were stable and resistant to repeated PAA pulses at 200 and 600 mg L(-1). This work demonstrated that the effect of PAA pulses on methanogenic activity and archaeal community structure differed according to AD substrate, and suggests that better insights of the correlations between archaeal population dynamics and functional performance could help to better face toxic shocks in AD
    In vitro detection of cardiotoxins or neurotoxins affecting ion channels or pumps using beating cardiomyocytes as alternative for animal testing
    Nicolas, J.A.Y. ; Hendriksen, P.J.M. ; Haan, L.H.J. de; Koning, R. ; Rietjens, I.M.C.M. ; Bovee, T.F.H. - \ 2015
    Toxicology in Vitro 29 (2015)2. - ISSN 0887-2333 - p. 281 - 288.
    gated sodium-channels - membrane currents - calcium-channel - open-state - tetrodotoxin - toxins - cells - na+ - diphenhydramine - inhibition
    The present study investigated if and to what extent murine stem cell-derived beating cardiomyocytes within embryoid bodies can be used as a broad screening in vitro assay for neurotoxicity testing, replacing for example in vivo tests for marine neurotoxins. Effect of nine model compounds, acting on either the Na+, K+, or Ca2+ channels or the Na+/K+ ATP-ase pump, on the beating was assessed. Diphenhydramine, veratridine, isradipine, verapamil and ouabain induced specific beating arrests that were reversible and none of the concentrations tested induced cytotoxicity. Three K+ channel blockers, amiodarone, clofilium and sematilide, and the Na+/K+ ATPase pump inhibitor digoxin had no specific effect on the beating. In addition, two marine neurotoxins i.e. saxitoxin and tetrodotoxin elicited specific beating arrests in cardiomyocytes. Comparison of the results obtained with cardiomyocytes to those obtained with the neuroblastoma neuro-2a assay revealed that the cardiomyocytes were generally somewhat more sensitive for the model compounds affecting Na+ and Ca2+ channels, but less sensitive for the compounds affecting K+ channels. The stem cell-derived cardiomyocytes were not as sensitive as the neuroblastoma neuro-2a assay for saxitoxin and tetrodotoxin. It is concluded that the murine stem cell-derived beating cardiomyocytes provide a sensitive model for detection of specific neurotoxins and that the neuroblastoma neuro-2a assay may be a more promising cell-based assay for the screening of marine biotoxins
    Optimizing the performance of a reactor by reducing the retention time and addition of glycerin for anaerobically digesting manure
    Timmerman, M. ; Schuman, E. ; Eekert, M. ; Riel, J.W. van - \ 2015
    Environmental Technology 36 (2015)10. - ISSN 0959-3330 - p. 1223 - 1236.
    co-digestion - methane production - crude glycerin - cattle manure - biogas - waste - biogasification - inhibition - ammonia
    Anaerobic digestion of manure is a widely accepted technology for energy production. However, only a minimal portion of the manure production in the EU is anaerobically digested and occurs predominantly in codigestion plants. There is substantial potential for biogas plants that primarily operate on manure (>90%); however, the methane yields of manure are less compared to coproducts, which is one of the reasons for manure-based biogas plants often being economically non-viable. Therefore, it is essential to begin increasing the efficiency of these biogas plants. This study investigated the effect of decreasing retention time and introducing a moderate amount of glycerin on the biogas production as methods to improve efficiency. An experiment has been conducted with two different manure types in four biogas reactors. The results of the study demonstrated that, first, it was possible to decrease the retention time to 10–15 days; however, the effect on biogas production varied per manure type. Secondly, the biogas production almost triples at a retention time of 15.6 days with an addition of 4% glycerin. The relative production-enhancing effect of glycerin did not vary significantly with both manure types. However, the absolute production-enhancing effect of glycerin differed per manure type since the biogas production per gram VS differed per manure type. Thirdly, the positive effect of the glycerin input declines with shorter retention times. Therefore, the effect of glycerin addition depends on the manure type and retention time.
    Live Faecalibacterium prausnitzii in an apical anaerobic model of the intestinal epithelial barrier
    Ulluwishewa, D. ; Anderson, R.C. ; Young, W. ; McNabb, W.C. ; Baarlen, P. van; Moughan, P.J. ; Wells, J.M. ; Roy, N.C. - \ 2015
    Cellular Microbiology 17 (2015)2. - ISSN 1462-5814 - p. 226 - 240.
    necrosis-factor-alpha - crohns-disease - fusobacterium-prausnitzii - celiac-disease - hypoxia - permeability - expression - microbiota - diversity - inhibition
    Faecalibacterium prausnitzii, an abundant member of the human commensal microbiota, has been proposed to have a protective role in the intestine. However, it is an obligate anaerobe, difficult to co-culture in viable form with oxygen-requiring intestinal cells. To overcome this limitation, a unique apical anaerobic model of the intestinal barrier, which enabled co-culture of live obligate anaerobes with the human intestinal cell line Caco-2, was developed. Caco-2 cells remained viable and maintained an intact barrier for at least 12¿h, consistent with gene expression data, which suggested Caco-2 cells had adapted to survive in an oxygen-reduced atmosphere. Live F.¿prausnitzii cells, but not ultraviolet (UV)-killed F.¿prausnitzii, increased the permeability of mannitol across the epithelial barrier. Gene expression analysis showed inflammatory mediators to be expressed at lower amounts in Caco-2 cells exposed to live F.¿prausnitzii than UV-killed F.¿prausnitzii, This, consistent with previous reports, implies that live F.¿prausnitzii produces an anti-inflammatory compound in the culture supernatant, demonstrating the value of a physiologically relevant co-culture system that allows obligate anaerobic bacteria to remain viable.
    Nitrogen-depleted Chlorella zofingiensis produces astaxanthin, ketolutein and their fatty acid esters: a carotenoid metabolism study
    Mulders, K.J.M. ; Weesepoel, Y.J.A. ; Bodenes, C. ; Lamers, P.P. ; Vincken, J.P. ; Martens, D.E. ; Gruppen, H. ; Wijffels, R.H. - \ 2015
    Journal of Applied Phycology 27 (2015)1. - ISSN 0921-8971 - p. 125 - 140.
    alga haematococcus-pluvialis - green-alga - triacylglycerol accumulation - biosynthetic-pathway - dunaliella-salina - light - chlorophyceae - inhibition - microalgae - complex
    Natural carotenoids such as astaxanthin, ß,ß-carotene and lutein are pigments with a high market value. We studied the effects of nitrogen depletion on the carotenoid metabolism of Chlorella zofingiensis (Chlorophyta) and the subsequent treatment with diphenylamine (DPA), an inhibitor of the biosynthesis of secondary ketocarotenoids. Pigments were identified and quantified based on reversed phase ultrahigh performance liquid chromatography photodiode array tandem mass spectrometry (RP-UHPLC-PDA-MSn). Nitrogen depletion (without DPA) resulted in a degradation of chlorophylls and primary carotenoids and an accumulation of astaxanthin, ketolutein, canthaxanthin, adonixanthin and ß,ß-carotene. The DPA treatment decreased the overall production of ß,ß-carotene derivatives (sum of astaxanthin, canthaxanthin, echinenone and adonixanthin); however, the production of ketolutein and degradation of primary carotenoids were not modified. This suggests that the regulatory mechanisms controlling the flux towards ketolutein and primary carotenoids were not affected by the decreased levels of ß,ß-carotene derivatives. In addition, DPA increased production of the individual carotenoids, adonixanthin and echinenone. Insight into the regulation of microalgal carotenoid biosynthesis as demonstrated in this paper is essential when a large-scale carotenoid production process is to be optimised or a recombinant C. ofingiensis strain is to be designed with the intention of excessively producing primary or secondary carotenoids.
    Impact of interspecific interactions on antimicrobial activity among soil bacteria
    Tyc, O. ; Berg, M. van den; Gerards, S. ; Veen, J.A. van; Raaijmakers, J.M. ; Boer, W. de; Garbeva, P. - \ 2014
    Frontiers in Microbiology 5 (2014). - ISSN 1664-302X
    community composition - bacillus-subtilis - gene-expression - antibiotics - diversity - rhizosphere - inhibition - environment - resistance - reveals
    Certain bacterial species produce antimicrobial compounds only in the presence of a competing species. However, little is known on the frequency of interaction-mediated induction of antibiotic compound production in natural communities of soil bacteria. Here we developed a high-throughput method to screen for the production of antimicrobial activity by monocultures and pair-wise combinations of 146 phylogenetically different bacteria isolated from similar soil habitats. Growth responses of two human pathogenic model organisms, Escherichia coli WA321 and Staphylococcus aureus 533R4, were used to monitor antimicrobial activity. From all isolates, 33% showed antimicrobial activity only in monoculture and 42% showed activity only when tested in interactions. More bacterial isolates were active against S. aureus than against E. coli. The frequency of interaction-mediated induction of antimicrobial activity was 6% (154 interactions out of 2798) indicating that only a limited set of species combinations showed such activity. The screening revealed also interaction-mediated suppression of antimicrobial activity for 22% of all combinations tested. Whereas all patterns of antimicrobial activity (non-induced production, induced production and suppression) were seen for various bacterial classes, interaction-mediated induction of antimicrobial activity was more frequent for combinations of Flavobacteria and alpha- Proteobacteria. The results of our study give a first indication on the frequency of interference competitive interactions in natural soil bacterial communities which may forms a basis for selection of bacterial groups that are promising for the discovery of novel, cryptic antibiotics.
    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.
    Effect of Selected Plant Extracts and D- and L-Lysine on the Cyanobacterium Microcystis aeruginosa
    Lurling, M.F.L.L.W. ; Oosterhout, J.F.X. - \ 2014
    Water 6 (2014)6. - ISSN 2073-4441 - p. 1807 - 1825.
    moringa-oleifera seeds - controlling eutrophication - fresh-water - amino-acid - blooms - coagulation - inhibition - mechanism - substances - phosphorus
    We tested extracts from Fructus mume, Salvia miltiorrhiza and Moringa oleifera as well as L-lysine and D-Lysine as curative measures to rapidly suppress the cyanobacterium Microcystis aeruginosa NIVA-CYA 43. We tested these compounds under similar conditions to facilitate comparisons. We hypothesized that for each compound, relatively low concentrations—i.e., 5–50 mg L-1, would reduce M. aeruginosa biomass. At these low concentrations, only L-lysine caused a decline in M. aeruginosa biomass at =4.3 mg L-1. F. mume extract was effective to do so at high concentrations, i.e., at =240 mg L-1, but the others were virtually non-effective. Low pH caused by organic acids is a probable explanation for the effect of F. mume extract. No complete wipe-outs of the experimental population were achieved as Photosystem II efficiency showed a recovery after six days. L-lysine may be effective at low concentrations—meaning low material costs. However, the effect of L-lysine seems relatively short-lived. Overall, the results of our study did not support the use of the tested plant extracts and amino-acid as promising candidates for curative application in M. aeruginosa bloom control.
    Rice cytochrome P450 MAX1 homologs catalyze distinct steps in strigolactone biosynthesis
    Zhang, Y. ; Dijk, A.D.J. van; Scaffidi, A. ; Flematti, G.R. ; Hofmann, M. ; Charnikhova, T. ; Verstappen, F.W.A. ; Hepworth, J. ; Krol, A.R. van der; Leyser, O. - \ 2014
    Nature Chemical Biology 10 (2014). - ISSN 1552-4450 - p. 1028 - 1033.
    arbuscular mycorrhizal fungi - structural requirements - germination stimulants - biological-activities - arabidopsis-thaliana - crystal-structures - plant hormones - protein - inhibition - expression
    Strigolactones (SLs) are a class of phytohormones and rhizosphere signaling compounds with high structural diversity. Three enzymes, carotenoid isomerase DWARF27 and carotenoid cleavage dioxygenases CCD7 and CCD8, were previously shown to convert all-trans-¿-carotene to carlactone (CL), the SL precursor. However, how CL is metabolized to SLs has remained elusive. Here, by reconstituting the SL biosynthetic pathway in Nicotiana benthamiana, we show that a rice homolog of Arabidopsis MORE AXILLARY GROWTH 1 (MAX1), encodes a cytochrome P450 CYP711 subfamily member that acts as a CL oxidase to stereoselectively convert CL into ent-2'-epi-5-deoxystrigol (B-C lactone ring formation), the presumed precursor of rice SLs. A protein encoded by a second rice MAX1 homolog then catalyzes the conversion of ent-2'-epi-5-deoxystrigol to orobanchol. We therefore report that two members of CYP711 enzymes can catalyze two distinct steps in SL biosynthesis, identifying the first enzymes involved in B-C ring closure and a subsequent structural diversification step of SLs.
    Differential Activity of Striga hermonthica Seed Germination Stimulants and Gigaspora rosea Hyphal Branching Factors in Rice and Their Contribution to Underground Communication
    Cardoso, C. ; Charnikhova, T. ; Jamil, M. ; Delaux, P.M. ; Verstappen, F.W.A. ; Amini, M. ; Lauressergues, D. ; Ruyter-Spira, C.P. ; Bouwmeester, H.J. - \ 2014
    PLoS ONE 9 (2014)8. - ISSN 1932-6203
    arbuscular mycorrhizal fungi - strigolactone production - structural requirements - phosphorus deficiency - phosphate deficiency - gesnerioides seeds - plant hormones - root parasites - red-clover - inhibition
    Strigolactones (SLs) trigger germination of parasitic plant seeds and hyphal branching of symbiotic arbuscular mycorrhizal (AM) fungi. There is extensive structural variation in SLs and plants usually produce blends of different SLs. The structural variation among natural SLs has been shown to impact their biological activity as hyphal branching and parasitic plant seed germination stimulants. In this study, rice root exudates were fractioned by HPLC. The resulting fractions were analyzed by MRM-LC-MS to investigate the presence of SLs and tested using bioassays to assess their Striga hermonthica seed germination and Gigaspora rosea hyphal branching stimulatory activities. A substantial number of active fractions were revealed often with very different effect on seed germination and hyphal branching. Fractions containing (-)-orobanchol and ent-2'-epi-5-deoxystrigol contributed little to the induction of S. hermonthica seed germination but strongly stimulated AM fungal hyphal branching. Three SLs in one fraction, putative methoxy-5-deoxystrigol isomers, had moderate seed germination and hyphal branching inducing activity. Two fractions contained strong germination stimulants but displayed only modest hyphal branching activity. We provide evidence that these stimulants are likely SLs although no SL-representative masses could be detected using MRM-LC-MS. Our results show that seed germination and hyphal branching are induced to very different extents by the various SLs (or other stimulants) present in rice root exudates. We propose that the development of rice varieties with different SL composition is a promising strategy to reduce parasitic plant infestation while maintaining symbiosis with AM fungi.
    Continuous xylose fermentation by Clostridium acetobutylicum – Kinetics and energetics issues under acidogenesis conditions
    Procentese, A. ; Raganati, F. ; Olivieri, G. ; Russo, M.E. ; Salatino, P. ; Marzocchella, A. - \ 2014
    Bioresource Technology 164 (2014). - ISSN 0960-8524 - p. 155 - 161.
    acetone-butanol fermentation - continuous lactose fermentation - biobutanol - biomass - growth - inhibition - energy
    The paper reports the assessment of the growth kinetics of Clostridium acetobutylicum DSM 792 adopting xylose as carbon source. Xylose is the fundamental component of hemicellulose hydrolysis, a relevant fraction of lignocellulosic feedstocks for biofuel production. Tests were carried out in a CSTR operated under controlled pH. The effects of acids (acetic and butyric) and solvents (acetone, ethanol and butanol) on the fermentation were investigated. The conversion process was characterized under steady-state conditions in terms of concentration of xylose, cells, acids, and pH. The growth kinetics was expressed by means of a multiple product inhibition and it was able to predict microorganism growth rate under a broad interval of operating conditions, even those typical of solvents production. The mass fractional yield of biomass and products were expressed as a function of the specific growth rate taking into account the Pirt model.
    The natural basil flavonoid nevadensin protects against induction of markers of hepatocarcinogenicity by methyleugenol in male F344 rat
    Alhusainy, W. ; Williams, G. ; Jeffrey, A.M. ; Iatropoulos, M.J. ; Taylor, S. ; Adams, T.B. ; Rietjens, I. - \ 2014
    Food and Chemical Toxicology 74 (2014). - ISSN 0278-6915 - p. 28 - 34.
    naturally-occurring alkenylbenzenes - post-labeling analysis - dna-adducts - preneoplastic lesions - mouse-liver - estragole - inhibition - safrole - mice - 1'-hydroxyestragole
    The alkenylbenzene methyleugenol occurs naturally in a variety of spices and herbs, including basil, and their essential oils. At high dose levels methyleugenol induces hepatocarcinogenicity in rodents following bioactivation to 1'-sulfooxymethyleugenol which forms DNA adducts. This study investigated whether the inhibitory effect of the basil flavonoid nevadensin on sulfotransferase (SULT)-mediated bioactivation of methyleugenol observed in vitro would also be reflected in a reduction of DNA adduct formation and a reduction in an early marker for liver carcinogenesis in an 8-week rat study. Co-exposure to methyleugenol and nevadensin orally resulted in a significant inhibition of liver methyleugenol DNA adduct formation and in inhibition of hepatocellular altered foci induction, representing indicators for initiation of neoplasia. These results suggest that tumor formation could be lower in rodent bioassays when methyleugenol would be dosed in a matrix containing SULT inhibitors such as nevadensin compared to experiments using the pure methyleugenol.
    Factors Impeding Enzymatic Wheat Gluten Hydrolysis at High Solid Concentrations
    Hardt, N.A. ; Janssen, A.E.M. ; Boom, R.M. ; Goot, A.J. van der - \ 2014
    Biotechnology and Bioengineering 111 (2014)7. - ISSN 0006-3592 - p. 1304 - 1312.
    functional-properties - water activity - plastein synthesis - biomass - lignocellulose - inhibition - proteins - softwood
    Enzymatic wheat gluten hydrolysis at high solid concentrations is advantageous from an environmental and economic point of view. However, increased wheat gluten concentrations result in a concentration effect with a decreased hydrolysis rate at constant enzyme-to-substrate ratios and a decreased maximum attainable degree of hydrolysis (DH%). We here identified the underlying factors causing the concentration effect. Wheat gluten was hydrolyzed at solid concentrations from 4.4% to 70%. The decreased hydrolysis rate was present at all solid concentrations and at any time of the reaction. Mass transfer limitations, enzyme inhibition and water activity were shown to not cause this hydrolysis rate limitation up to 50% solids. However, the hydrolysis rate limitation can be, at least partly, explained by a second-order enzyme inactivation process. Furthermore, mass transfer impeded the hydrolysis above 60% solids. Addition of enzyme after 24 h at high solid concentrations scarcely increased the DH%, suggesting that the maximum attainable DH% decreases at high solid concentrations. Reduced enzyme activities caused by low water activities can explain this DH% limitation. Finally, a possible influence of the plastein reaction on the DH% limitation is discussed.
    Striga hermonthica MAX2 restores branching but not the Very Low Fluence Response in the Arabidopsis thaliana max2 mutant
    Liu, Q. ; Zhang, Y. ; Matusovaa, R. ; Charnikhova, T. ; Amini, M. ; Jamil, M. ; Fernandez-Aparicio, M. ; Huang, K. ; Timko, M.P. ; Westwood, J.H. ; Ruyter-Spira, C.P. ; Krol, A.R. van der; Bouwmeester, H.J. - \ 2014
    New Phytologist 202 (2014)2. - ISSN 0028-646X - p. 531 - 541.
    arabidopsis seed-germination - box protein max2 - plant hormone - strigolactone - inhibition - photomorphogenesis - stimulants - karrikins - molecule - pathway
    Seed germination of Striga spp. (witchweeds), one of the world’s most destructive parasitic weeds, cannot be induced by light but is specifically induced by strigolactones. It is not known whether Striga uses the same components for strigolactone signaling as host plants, whether it has endogenous strigolactone biosynthesis and whether there is post-germination strigolactone signaling in Striga. Strigolactones could not be detected in in vitro grown Striga, while for host-grown Striga, the strigolactone profile is dominated by a subset of the strigolactones present in the host. Branching of in vitro grown Striga is affected by strigolactone biosynthesis inhibitors. ShMAX2, the Striga ortholog of Arabidopsis MORE AXILLARY BRANCHING 2 (AtMAX2) – which mediates strigolactone signaling – complements several of the Arabidopsis max2-1 phenotypes, including the root and shoot phenotype, the High Irradiance Response and the response to strigolactones. Seed germination of max2-1 complemented with ShMAX2 showed no complementation of the Very Low Fluence Response phenotype of max2-1. Results provide indirect evidence for ShMAX2 functions in Striga. A putative role of ShMAX2 in strigolactone-dependent seed germination of Striga is discussed.
    Natural variation of rice strigolactone biosynthesis is associated with the deletion of two MAX1 orthologs
    Cardoso, C. ; Zhang, Y. ; Jamil, M. ; Hepworth, J. ; Charnikhova, T. ; Dimkpa, S.O.N. ; Reiff, C. ; Wright, M.H. ; Liu, J. ; Meng, X. ; Bouwmeester, H.J. ; Ruyter-Spira, C.P. - \ 2014
    Proceedings of the National Academy of Sciences of the United States of America 111 (2014)6. - ISSN 0027-8424 - p. 2379 - 2384.
    arbuscular mycorrhizal fungi - quantitative trait loci - tiller bud outgrowth - striga-hermonthica - oryza-sativa - phosphate deficiency - root morphology - arabidopsis - architecture - inhibition
    Rice (Oryza sativa) cultivar Azucena—belonging to the Japonica subspecies—exudes high strigolactone (SL) levels and induces high germination of the root parasitic plant Striga hermonthica. Consistent with the fact that SLs also inhibit shoot branching, Azucena is a lowtillering variety. In contrast, Bala, an Indica cultivar, is a low-SL producer, stimulates less Striga germination, and is highly tillered. Using a Bala × Azucena F6 population, a major quantitative trait loci— qSLB1.1—for the exudation of SL, tillering, and induction of Striga germination was detected on chromosome 1. Sequence analysis of the corresponding locus revealed a rearrangement of a 51- to 59-kbp stretch between 28.9 and 29 Mbp in the Bala genome, resulting in the deletion of two cytochrome P450 genes—SLB1 and SLB2—with high homology to the Arabidopsis SL biosynthesis gene, MAX1. Both rice genes rescue the Arabidopsis max1-1 highly branched mutant phenotype and increase the production of the SL, ent-2'-epi-5-deoxystrigol, when overexpressed in Bala. Furthermore, analysis of this region in 367 cultivars of the publicly available Rice Diversity Panel population shows that the rearrangement at this locus is a recurrent natural trait associated with the Indica/Japonica divide in rice.
    Agaricus Blazei Hot Water Extract Shows Anti Quorum Sensing Activity in the Nosocomial Human PathogenPseudomonas Aeruginosa
    Sokovic, M. ; Ciric, A. ; Glamoclija, J. ; Nicolic, M. ; Griensven, L.J.L.D. van - \ 2014
    Molecules 19 (2014). - ISSN 1420-3049 - p. 4189 - 4199.
    medicinal mushroom - biofilm formation - inhibition - resistance - infection - virulence - impact - mice
    The edible mushroom Agaricus blazei Murill is known to induce protective immunomodulatory action against a variety of infectious diseases. In the present study we report potential anti-quorum sensing properties of A. blazei hot water extract. Quorum sensing (QS) plays an important role in virulence, biofilm formation and survival of many pathogenic bacteria, including the Gram negative Pseudomonas aeruginosa, and is considered as a novel and promising target for anti-infectious agents. In this study, the effect of the sub-MICs of Agaricus blazei water extract on QS regulated virulence factors and biofilm formation was evaluated against P. aeruginosa PAO1. Sub-MIC concentrations of the extract which did not kill P. aeruginosa nor inhibited its growth, demonstrated a statistically significant reduction of virulence factors of P. aeruginosa, such as pyocyanin production, twitching and swimming motility. The biofilm forming capability of P. aeruginosa was also reduced in a concentration-dependent manner at sub-MIC values. Water extract of A. blazei is a promising source of antiquorum sensing and antibacterial compounds. Keywords: Agaricus blazei; mushroom; antiqourum sensing activity; antimicrobial activity; antibiofilm activity; Pseudomonas aeruginosa.
    Improved poliovirus d-antigen yields by application of different Vero cell cultivation methods
    Thomassen, Y.E. ; Rubingh, O. ; Wijffels, R.H. ; Pol, L.A. van der - \ 2014
    Vaccine 32 (2014)24. - ISSN 0264-410X - p. 2782 - 2788.
    culture process - rabies virus - vaccine - microcarrier - replication - inhibition - bioreactor - metabolism - growth
    Vero cells were grown adherent to microcarriers (Cytodex 1; 3 g L-1) using animal component free media in stirred-tank type bioreactors. Different strategies for media refreshment, daily media replacement (semi-batch), continuous media replacement (perfusion) and recirculation of media, were compared with batch cultivation. Cell densities increased using a feed strategy from 1 × 106 cells mL-1 during batch cultivation to 1.8, 2.7 and 5.0 × 106 cells mL-1 during semi-batch, perfusion and recirculation, respectively. The effects of these different cell culture strategies on subsequent poliovirus production were investigated. Increased cell densities allowed up to 3 times higher d-antigen levels when compared with that obtained from batch-wise Vero cell culture. However, the cell specific d-antigen production was lower when cells were infected at higher cell densities. This cell density effect is in good agreement with observations for different cell lines and virus types. From the evaluated alternative culture methods, application of a semi-batch mode of operations allowed the highest cell specific d-antigen production. The increased product yields that can easily be reached using these higher cell density cultivation methods, showed the possibility for better use of bioreactor capacity for the manufacturing of polio vaccines to ultimately reduce vaccine cost per dose. Further, the use of animal-component-free cell- and virus culture media shows opportunities for modernization of human viral vaccine manufacturing.
    Efficient Purification of Ginkgolic Acids from Ginkgo biloba Leaves by Selective Adsorption of Fe3O4 Magnetic Nanoparticles
    Li, R. ; Shen, Y. ; Zhang, X. ; Ma, M. ; Chen, B. ; Beek, T.A. van - \ 2014
    Journal of Natural Products 77 (2014)3. - ISSN 0163-3864 - p. 571 - 575.
    anacardic acids - 6-pentadecylsalicylic acid - shell liquid - acetoacetate - inhibition - apoptosis - extracts - quality - cells
    Ginkgolic acids (GAs; anacardic acids; 6-alkylsalicylic acids) are both unwanted constituents in standardized Ginkgo biloba (Ginkgo) extracts and desirable constituents for pharmacological assays. Thus, for the quality control of Ginkgo extracts, the availability of pure GAs is important. In this investigation, inexpensive and easily prepared Fe3O4 magnetic nanoparticles (MNPs) in methanol were used to selectively adsorb GAs from crude petroleum ether extracts of Ginkgo leaves in the presence of various lipids including other alkylphenols (cardanols and cardols). The adsorption capacity of the MNPs is high, at 4–5% (w/w). The moiety responsible for the adsorption is the salicylic acid group, which binds strongly to Fe(III). Desorption with acidified methanol gave an extract with a GA content of 73%. This could be further separated by preparative HPLC on a C8 column. In total, eight different GAs were captured by MNPs. The MNP adsorption step can replace more traditional column chromatography and liquid–liquid extraction steps and is superior in terms of solvent consumption, selectivity, labor, and energy consumption. MNPs might become an efficient separation technique for selected high-value phytochemicals that contain a salicylic acid moiety.
    Two-stage medium chain fatty acid (MCFA) production from municipal solid waste and ethanol
    Grootscholten, T.I.M. ; Strik, D.P.B.T.B. ; Steinbusch, K.J.J. ; Buisman, C.J.N. ; Hamelers, B. - \ 2014
    Applied Energy 116 (2014)1. - ISSN 0306-2619 - p. 223 - 229.
    clostridium-kluyveri - carboxylic-acids - carbon-dioxide - elongation - biomass - inhibition - caprylate - caproate - bacteria - acetate
    Chain elongation is an anaerobic fermentation that produces medium chain fatty acids (MCFAs) from volatile fatty acids and ethanol. These MCFAs can be used as biochemical building blocks for fuel production and other chemical processes. Producing MCFAs from the organic fraction of municipal solid waste (OFMSW) is attractive because it combines waste treatment with biochemical production. We investigated whether higher MCFA production rates can be achieved from OFMSW by applying a two-stage conversion, consisting of the OFMSW acidification step followed by chain elongation, compared to a single-stage system. We obtained higher MCFA production rates with a two-stage system than with a single-stage system. The obtained caproate concentrations were above the solubility of caproic acid in water. Furthermore, this work discussed competitive processes for MCFA production and shows how these processes can be controlled in a two-stage system. Finally an outlook was given on research required to prevent too much production of the intermediate co-product butyrate instead of MCFAs, which occurred several times during the experiment.
    Down-regulation of acetolactate synthase compromises OI-1- mediated resistance to powdery mildew in tomato
    Gao, D. ; Huibers, R.P. ; Loonen, A.E.H.M. ; Visser, R.G.F. ; Wolters, A.M.A. ; Bai, Y. - \ 2014
    BMC Plant Biology 14 (2014). - ISSN 1471-2229 - 11 p.
    glutamate-dehydrogenase gene - acetohydroxyacid synthase - monogenic-resistance - defense responses - nicotiana-tabacum - ol-genes - arabidopsis - plants - inhibition - biosynthesis
    Background - In a cDNA-AFLP analysis comparing transcript levels between powdery mildew (Oidium neolycopersici)-susceptible tomato cultivar Moneymaker (MM) and near isogenic lines (NILs) carrying resistance gene Ol-1 or Ol-4, a transcript-derived fragment (TDF) M11E69-195 was found to be present in NIL-Ol-1 but absent in MM and NIL-Ol-4. This TDF shows homology to acetolactate synthase (ALS). ALS is a key enzyme in the biosynthesis of branched-chain amino acids valine, leucine and isoleucine, and it is also a target of commercial herbicides. Results - Three ALS homologs ALS1, ALS2, ALS3 were identified in the tomato genome sequence. ALS1 and ALS2 show high similarity, whereas ALS3 is more divergent. Transient silencing of both ALS1 and ALS2 in NIL-Ol-1 by virus-induced gene silencing (VIGS) resulted in chlorotic leaf areas that showed increased susceptibility to O. neolycopersici (On). VIGS results were confirmed by stable transformation of NIL-Ol-1 using an RNAi construct targeting both ALS1 and ALS2. In contrast, silencing of the three ALS genes individually by RNAi constructs did not compromise the resistance of NIL-Ol-1. Application of the herbicide chlorsulfuron to NIL-Ol-1 mimicked the VIGS phenotype and caused loss of its resistance to On. Susceptible MM and On-resistant line NIL-Ol-4 carrying a nucleotide binding site and leucine rich repeat (NB-LRR) resistance gene were also treated with chlorsulfuron. Neither the susceptibility of MM nor the resistance of NIL-Ol-4 was affected. Conclusions - ALS is neither involved in basal defense, nor in resistance conferred by NB-LRR type resistance genes. Instead, it is specifically involved in Ol-1-mediated resistance to tomato powdery mildew, suggesting that ALS-induced change in amino acid homeostasis is important for resistance conferred by Ol-1.
    Responses of supplemental blue light on flowering and stem extension growth of cut chrysanthemum
    Jeong, S.W. ; Hogewoning, S.W. ; Ieperen, W. van - \ 2014
    Scientia Horticulturae 165 (2014). - ISSN 0304-4238 - p. 69 - 74.
    plant-growth - spectral filters - red - morifolium - photosynthesis - gibberellins - phytochrome - end - photoperiod - inhibition
    To determine the effects of blue (B) spectrum supplemental lighting on flower bud formation and stem elongation growth of cut chrysanthemum, plants of ‘Zembla’ cultivar were grown for 42 days under 4 different light treatments. Treatments comprised: RB (11 h of mixed red and blue [RB] light), RB + B (11 h of mixed RB light and then 4 h of supplemental B light), LRB + B (15 h of mixed RB light and then 4 h of supplemental B light) and RB + LB (11 h of mixed RB light and then 13 h of B light) by using light-emitting diodes. Diurnal patterns in the net assimilation rate were observed, depending on light-quality combinations. Under mixed RB light, the net assimilation rate increased rapidly, then slightly decreased under B light, and finally dropped to negative values during darkness. Final stem length was the highest in plants grown under RB + LB, followed by LRB + B, RB + B and then RB treatment. The stem lengths under RB + B, LRB + B and RB + LB were 1.3, 1.5 and 1.7 times longer than that of RB treatment, respectively. However, fully developed flower buds were formed under RB and RB + B treatments only. The extended final stem length of RB + B plants was determined by internode extension. Overall, our results indicate that supplemental B light, at least in part, may promote stem and internode elongation growth without any inhibitory effect on flower bud formation. The results of this study present a useful practical technique for optimizing cut chrysanthemum production in greenhouse horticulture.
    Methane reduction by plant pigments and antioxidants in rumen fluid involves modifications, e.g. hydrogenatioor degradation of the active compoundsn,
    Becker, P.M. ; Wikselaar, P.G. van; Ilgenfritz, J. ; Beekwilder, M.J. ; Vos, R.C.H. de; Franz, C.H. ; Zitterl-Eglseer, K. - \ 2013
    Wiener Tierarztliche Monatsschrift 100 (2013). - ISSN 0043-535X - p. 295 - 305.
    bacteria - methanogenesis - anthocyanins - cleavage - bilberry - bisdemethoxycurcumin - demethoxycurcumin - resveratrol - inhibition - emissions
    Methane is a major greenhouse gas, and ruminants cause about a quarter of all anthropogenic methane emissions. The objective of this study was to testplant secondary products in terms of their effects on methane production, and to follow active compounds analytically during incubation. In a simplifi ed model of ruminal methane production, a glycerol tripolylactate served as a central metabolites-generating and hydrogen-releasing substrate for rumen prokaryotes. The experimental additives, tested for their interfering potential with methane production, comprised bilberry fruit extract, tomato paste, paprika powder, grape seed extract, turmeric powder, curcumin, catechin, ferulic acid, ferulic acid ethyl ester and resveratrol. Being an unsaturated compound, fumarate, a competing electron acceptor to methane precursors, served as a well-described methane-reducing compound among the experimental additives in the in vitro tests. Methanemitigating effi ciencies were calculated by subtraction of the methane quantity produced in fl asks with the interfering additives from the quantity measured without any additive. Grape seed extract, bilberry fruit extract, turmeric powder, ferulic acid, catechin, and resveratrol reduced the production of methane in vitro. Grape seed extract, bilberry fruit extract, catechin, and resveratrol decreased methane formation to a higher extent than fumarate when added at comparable concentrations. Analysis of the secondary compounds in the assays by means of HPLC and revealed a considerably and in most cases significant (p
    Dietary modulation of plasma angiopoietin-like protein 4 concentrations in healthy volunteers and in patients with type 2 diabetes
    Jonker, J.T. ; Smit, J.W.A. ; Hammer, S. ; Snel, M. ; Meer, R. van der; Lamb, H.J. ; Mattijssen, F.B.J. ; Mudde, C.M. ; Jazet, I.M. ; Dekkers, O.M. ; Roos, A. de; Romijn, J.A. ; Kersten, A.H. ; Rensen, P.C.N. - \ 2013
    American Journal of Clinical Nutrition 97 (2013)2. - ISSN 0002-9165 - p. 255 - 260.
    myocardial triglyceride content - free fatty-acids - lipoprotein-lipase - caloric restriction - diastolic function - angptl4 - mice - hyperlipidemia - inhibition - humans
    Background: Angiopoietin-like protein 4 (ANGPTL4) has been identified as an inhibitor of lipoprotein lipase. Preliminary data suggest that plasma nonesterified fatty acids (NEFAs) raise plasma ANGPTL4 concentrations in humans. Objective: The objective was to assess plasma ANGPTL4 concentrations after various nutritional interventions that increase NEFA concentrations in healthy subjects and in patients with type 2 diabetes mellitus. Design: We studied 4 groups, both at baseline and after 3 d of either fasting (n = 22 healthy men), a very-low-calorie diet (VLCD; n = 10 healthy men and n = 10 patients with diabetes), or a high-fat, high-energy diet (HFED; n = 15 healthy men). Plasma ANGPTL4, NEFA, and triglyceride concentrations were measured. Results: In healthy men, a VLCD increased ANGPTL4 from 13.2 (IQR: 8.1-24.2) at baseline to 18.2 (16.7-33.4) ng/mL (P <0.05), fasting increased ANGPTL4 from 10.6 (7.6-17.6) to 28.0 (23.1-35.0) ng/mL (P <0.05), and an HFED increased ANGPTL4 from 13.9 (8.2-22.0) to 17.2 (11.2-23.6) ng/mL (P <0.05). In men with diabetes, a VLCD also increased ANGPTL4, from 10.9 +/- 2.4 to 19.2 +/- 3.2 ng/mL (P <0.05). All interventions significantly increased plasma NEFAs in both healthy men and patients with diabetes. The change in ANGPTL4 positively correlated with the change in NEFA concentrations (beta = 0.048, P <0.001) and negatively correlated with the change in plasma triglycerides (beta = -0.051, P = 0.01). Conclusions: Three days of either fasting, a VLCD, or an HFED increased plasma ANGPTL4 concentrations in healthy men, concomitantly with increased plasma NEFA concentrations. Similarly, a VLCD in patients with diabetes increased ANGPTL4 concentrations, concomitantly with increased NEFA concentrations. Am J Clin Nutr 2013;97:255-60.
    Dietary protein, blood pressure and renal function in renal transplant recipients
    Berg, E. van den; Engberink, M.F. ; Brink, E.J. ; Baak, M.A. van; Gans, R.O.B. ; Navis, G. ; Bakker, S.J.L. - \ 2013
    The British journal of nutrition 109 (2013)8. - ISSN 0007-1145 - p. 1463 - 1470.
    kidney-transplantation - cardiovascular-disease - sodium-intake - follow-up - hypertension - restriction - association - progression - failure - inhibition
    Hypertension is highly prevalent among renal transplant recipients (RTR) and a risk factor for graft failure and cardiovascular events. Protein intake has been claimed to affect blood pressure (BP) in the general population and may affect renal function. We examined the association of dietary protein with BP and renal function in RTR. We included 625 RTR (age 53 (SD 13) years; 57% male). Protein intake was assessed with a FFQ, differentiating between animal and plant protein. BP was measured according to a strict protocol. Creatinine clearance and albuminuria were measured as renal parameters. Protein intake was 83 (SD 12) g/d, of which 63% derived from animal sources. BP was 136 (SD 17) mmHg systolic (SBP) and 83 (SD 11) mmHg diastolic (DBP). Creatinine clearance was 66 (SD 26) ml/min; albuminuria 41 (10-178) mg/24 h. An inverse, though statistically insignificant, association was found between the total protein intake and both SBP (beta = -2.22 mmHg per SD, P=0.07) and DBP (beta = -0.48 mmHg per SD, P=0.5). Protein intake was not associated with creatinine clearance. Although albuminuria was slightly higher in the highest tertile of animal protein intake compared with the lowest tertile (66 v. 33 mg/d, respectively, P=0.03), linear regression analyses did not reveal significant associations between dietary protein and albuminuria. Protein intake exceeded the current recommendations. Nevertheless, within the range of protein intake in our RTR population, we found no evidence for an association of dietary protein with BP and renal function. Intervention studies focusing on different protein types are warranted to clarify their effect on BP and renal function in RTR.
    Fate of Listeria monocytogenes in Gouda microcheese: No growth, and substantial inactivation after extended ripening times
    Wemmenhove, E. ; Stampelou, I. ; Hooijdonk, A.C.M. van; Zwietering, M.H. ; Wells-Bennik, M.H.J. - \ 2013
    International Dairy Journal 32 (2013)2. - ISSN 0958-6946 - p. 192 - 198.
    cheddar cheese - inoculum size - lactic-acid - behavior - manufacture - inhibition - survival - storage - milk - ph
    This challenge study demonstrates that Listeria monocytogenes does not grow in Gouda cheese: during the first 8 weeks of ripening no growth was observed and between 8 and 52 weeks viable numbers declined significantly in a well-established Gouda microcheese system. Cheese milk was artificially contaminated just prior to addition of the starter culture. Three individual L. monocytogenes strains were used, including strains originating from cheese, a cheese plant environment and a reference strain. During curd formation, viable numbers of L. monocytogenes increased by 0.5 log cfu g-1, resulting from entrapment in the curd. No growth was observed during the first 8 weeks of ripening. A significant decline in the viable numbers of L. monocytogenes was observed in Gouda cheese that was ripened for longer than 8 weeks. Two factors that could possibly control the fate of L. monocytogenes in Gouda cheese were lactic acid and water activity.
    Integration of first and second generation biofuels: Fermentative hydrogen production from wheat grain and straw
    Panagiotopoulos, I.A. ; Bakker, R.R.C. ; Vrije, G.J. de; Claassen, P.A.M. ; Koukios, E.G. - \ 2013
    Bioresource Technology 128 (2013). - ISSN 0960-8524 - p. 345 - 350.
    thermophiles caldicellulosiruptor-saccharolyticus - dilute-acid pretreatment - thermotoga-neapolitana - extreme thermophiles - bioethanol production - biomass - inhibition - conversion - ethanol - pulp
    Integrating of lignocellulose-based and starch-rich biomass-based hydrogen production was investigated by mixing wheat straw hydrolysate with a wheat grain hydrolysate for improved fermentation. Enzymatic pretreatment and hydrolysis of wheat grains led to a hydrolysate with a sugar concentration of 93.4 g/L, while dilute-acid pretreatment and enzymatic hydrolysis of wheat straw led to a hydrolysate with sugar concentration 23.0 g/L. Wheat grain hydrolysate was not suitable for hydrogen production by the extreme thermophilic bacterium Caldicellulosiruptor saccharolyticus at glucose concentrations of 10 g/L or higher, and wheat straw hydrolysate showed good fermentability at total sugar concentrations of up to 10 g/L. The mixed hydrolysates showed good fermentability at the highest tested sugar concentration of 20 g/L, with a hydrogen production of 82–97% of that of the control with pure sugars. Mixing wheat grain hydrolysate with wheat straw hydrolysate would be beneficial for fermentative hydrogen production in a biorefinery.
    IgG antibodies in food allergy influence allergen-antibody complex formation and binding to B cells: a role for complement receptors
    Meulenbroek, L.A. ; Jong, R.J. ; Hartog Jager, C.F. den; Monsuur, H.N. ; Wouters, D. ; Nauta, A. ; Knippels, L.M. ; Neerven, R.J.J. van; Ruiter, B. ; Leusen, J.H. ; Hack, C.E. ; Bruijnzeel-Koomen, C.A. ; Knulst, A.C. ; Garssen, J. ; Hoffen, E. van - \ 2013
    The Journal of Immunology 191 (2013)7. - ISSN 0022-1767 - p. 3526 - 3533.
    immune-responses - antigen presentation - blocking antibodies - natural antibody - peanut allergy - double-blind - fc regions - t-cells - activation - inhibition
    Allergen-IgE complexes are more efficiently internalized and presented by B cells than allergens alone. It has been suggested that IgG Abs induced by immunotherapy inhibit these processes. Food-allergic patients have high allergen-specific IgG levels. However, the role of these Abs in complex formation and binding to B cells is unknown. To investigate this, we incubated sera of peanut- or cow's milk-allergic patients with their major allergens to form complexes and added them to EBV-transformed or peripheral blood B cells (PBBCs). Samples of birch pollen-allergic patients were used as control. Complex binding to B cells in presence or absence of blocking Abs to CD23, CD32, complement receptor 1 (CR1, CD35), and/or CR2 (CD21) was determined by flow cytometry. Furthermore, intact and IgG-depleted sera were compared. These experiments showed that allergen-Ab complexes formed in birch pollen, as well as food allergy, contained IgE, IgG1, and IgG4 Abs and bound to B cells. Binding of these complexes to EBV-transformed B cells was completely mediated by CD23, whereas binding to PBBCs was dependent on both CD23 and CR2. This reflected differential receptor expression. Upon IgG depletion, allergen-Ab complexes bound to PBBCs exclusively via CD23. These data indicated that IgG Abs are involved in complex formation. The presence of IgG in allergen-IgE complexes results in binding to B cells via CR2 in addition to CD23. The binding to both CR2 and CD23 may affect Ag processing and presentation, and (may) thereby influence the allergic response.
    Activity and viability of methanogens in anaerobic digestion of unsaturated and saturated long-chain fatty acids
    Sousa, D.Z. ; Salvador, A.F. ; Ramos, J. ; Guedes, A.P. ; Barbosa, S. ; Stams, A.J.M. ; Alves, M.M. ; Pereira, M.A. - \ 2013
    Applied and Environmental Microbiology 79 (2013)14. - ISSN 0099-2240 - p. 4239 - 4245.
    16s ribosomal-rna - microbial communities - calcium addition - waste-water - oleic-acid - bacteria - inhibition - sludge - bioreactors - diversity
    Lipids can be anaerobically digested to methane, but methanogens are often considered to be highly sensitive to the long-chain fatty acids (LCFA) deriving from lipids hydrolysis. In this study, the effect of unsaturated (oleate [C18:1]) and saturated (stearate [C18:0] and palmitate [C16:0]) LCFA toward methanogenic archaea was studied in batch enrichments and in pure cultures. Overall, oleate had a more stringent effect on methanogens than saturated LCFA, and the degree of tolerance to LCFA was different among distinct species of methanogens. Methanobacterium formicicum was able to grow in both oleate- and palmitate-degrading enrichments (OM and PM cultures, respectively), whereas Methanospirillum hungatei only survived in a PM culture. The two acetoclastic methanogens tested, Methanosarcina mazei and Methanosaeta concilii, could be detected in both enrichment cultures, with better survival in PM cultures than in OM cultures. Viability tests using live/dead staining further confirmed that exponential growth-phase cultures of M. hungatei are more sensitive to oleate than are M. formicicum cultures; exposure to 0.5 mM oleate damaged 99% ± 1% of the cell membranes of M. hungatei and 53% ± 10% of the cell membranes of M. formicicum. In terms of methanogenic activity, M. hungatei was inhibited for 50% by 0.3, 0.4, and 1 mM oleate, stearate, and palmitate, respectively. M. formicicum was more resilient, since 1 mM oleate and >4 mM stearate or palmitate was needed to cause 50% inhibition on methanogenic activity
    Effect of substrate and cation requirement on anaerobic volatile fatty acid conversion rates at elevated biogas pressure
    Lindeboom, R.E.F. ; Ferrer, I. ; Weijma, J. ; Lier, J.B. van - \ 2013
    Bioresource Technology 150 (2013). - ISSN 0960-8524 - p. 60 - 66.
    high-calorific biogas - digestion process - bacteria - hydrogen - fermentation - temperature - competition - inhibition - propionate - archaea
    This work studied the anaerobic conversion of neutralized volatile fatty acids (VFA) into biogas under Autogenerative High Pressure Digestion (AHPD) conditions. The effects of the operating conditions on the biogas quality, and the substrate utilisation rates were evaluated using 3 AHPD reactors (0.6 L); feeding a concentration of acetate and VFA (1–10 g COD/L) corresponding to an expected pressure increase of 1–20 bar. The biogas composition improved with pressure up to 4.5 bar (>93% CH4), and stabilized at 10 and 20 bar. Both, acetotrophic and hydrogenotrophic methanogenic activity was observed. Substrate utilisation rates of 0.2, 0.1 and 0.1 g CODCH4/g VSS/d for acetate, propionate and butyrate were found to decrease by up to 50% with increasing final pressure. Most likely increased Na+-requirement to achieve CO2 sequestration at higher pressure rather than end-product inhibition was responsible.
    New strigolactone mimics: structure-activity relationship and mode of action as germinating stimulants for parasitic weeds.
    Zwanenburg, B. ; Nayak, S.K. ; Charnikhova, T. ; Bouwmeester, H.J. - \ 2013
    Bioorganic and Medicinal Chemistry Letters 23 (2013)18. - ISSN 0960-894X - p. 5182 - 5186.
    seed-germination - orobanche-minor - plant hormones - am fungi - striga-hermonthica - red-clover - analogs - inhibition - ring - phelipanche
    Strigolactones (SLs) are new plant hormones with varies important bio-functions. This Letter deals with germination of seeds of parasitic weeds. Natural SLs have a too complex structure for synthesis. Therefore, there is an active search for SL analogues and mimics with a simpler structure with retention of activity. SL analogues all contain the D-ring connected with an enone moiety through an enol ether unit. A new mechanism for the hydrolysis SL analogues involving bidentate bound water and an a,ß-hydrolase with a Ser-His-Asp catalytic triad has been proposed. Newly discovered SL mimics only have the D-ring with an appropriate leaving group at C-5. A mode of action for SL mimics was proposed for which now supporting evidence is provided. As predicted an extra methyl group at C-4 of the D-ring blocks the germination of seeds of parasitic weeds.
    Four Hypotheses to Explain Axillary Budbreak after Removal of Flower Shoots in a Cut-rose Crop
    Wubs-Timmermans, A.M. ; Heuvelink, E. ; Marcelis, L.F.M. ; Okello, R.C. ; Buck-Sorlin, G.H. ; Vos, J. - \ 2013
    Journal of the American Society for Horticultural Science 138 (2013)4. - ISSN 0003-1062 - p. 243 - 252.
    photosynthetic photon flux - bud burst - plant architecture - light control - growth - inhibition - auxin - age - arabidopsis - temperature
    When flower-bearing shoots in cut-rose (Rosa ×hybrida) are harvested (removed), a varying number of repressed axillary buds on the shoot remainder start to grow into new shoots (budbreak). Besides removing within-shoot correlative inhibition, it is hypothesized that shoot removal leads to 1) increased light intensity lower in the crop canopy; 2) changes in the light spectrum (particularly red:far-red ratio); and 3) changed source:sink ratio (i.e., the ratio between supply and demand of assimilates). As a fourth hypothesis it is proposed that the degree of budbreak on a shoot remainder is also influenced by the correlative inhibition exerted by other shoots on the plant. It is the goal of this work to determine which of these four hypotheses is most important for budbreak in a cut-rose crop. Four experiments were conducted, in which these factors were varied by leaf removal, removal of mature shoots, varying the number of young shoots, shading of the crop, and application of direct light on the buds. Increase in source:sink ratio was not consistently associated with higher budbreak. If source:sink ratio was decreased by removal of leaves or a mature shoot, budbreak showed even a tendency to increase. Budbreak was subject to correlative inhibition exerted by other shoots on the plant. Treatments where more light reached the bud (as a result of less shoots, no shading of the crop, application of local light) increased budbreak. Increased red:far-red ratio had the same result as more light reaching the bud but was often interrelated with light intensity. It was concluded that after removal of the flower-bearing shoot, among the factors tested, light intensity on the buds was an important and consistent factor explaining budbreak on the shoot remainder, whereas the effect of light spectrum should be further investigated
    The anti-browning agent sulfite inactivates Agaricus bisporus tyrosinase through covalent modification of the copper-B site
    Kuijpers, T.F.M. ; Gruppen, H. ; Sforza, S. ; Berkel, W.J.H. van; Vincken, J.P. - \ 2013
    FEBS Journal 280 (2013)23. - ISSN 1742-464X - p. 6184 - 6195.
    glutathione conjugate formation - crystal-structure - mushroom tyrosinase - polyphenol oxidase - chlorogenic acid - plant - inhibition - metabolism - thioether - sequence
    Sulfite salts are widely used as antibrowning agents in food processing. Nevertheless, the exact mechanism by which sulfite prevents enzymatic browning has remained unknown. Here, we show that sodium hydrogen sulfite (NaHSO3 ) irreversibly blocks the active site of tyrosinase from the edible mushroom Agaricus bisporus, and that the competitive inhibitors tropolone and kojic acid protect the enzyme from NaHSO3 inactivation. LC-MS analysis of pepsin digests of NaHSO3 -treated tyrosinase revealed two peptides showing a neutral loss corresponding to the mass of SO3 upon MS(2) fragmentation. These peptides were found to be homologous peptides containing two of the three histidine residues that form the copper-B-binding site of mushroom tyrosinase isoform PPO3 and mushroom tyrosinase isoform PPO4, which were both present in the tyrosinase preparation used. Peptides showing this neutral loss behavior were not found in the untreated control. Comparison of the effects of NaHSO3 on apo-tyrosinase and holo-tyrosinase indicated that inactivation is facilitated by the active site copper ions. These data provide compelling evidence that inactivation of mushroom tyrosinase by NaHSO3 occurs through covalent modification of a single amino-acid residue, probably via addition of HSO3 (-) to one of the copper-coordinating histidines in the copper-B site of the enzyme
    Improving medium chain fatty acid productivity using chain elongation by reducing the hydraulic retention time in an upflow anaerobic filter
    Grootscholten, T.I.M. ; Steinbusch, K.J.J. ; Hamelers, H.V.M. ; Buisman, C.J.N. - \ 2013
    Bioresource Technology 136 (2013). - ISSN 0960-8524 - p. 735 - 738.
    clostridium-kluyveri - carboxylic-acids - ethanol - biomass - fermentation - inhibition - reduction
    The expansion of biofuel production can lead to an array of negative environmental impacts. Therefore, the European Union (EU) has recently imposed sustainability criteria on biofuel production in the Renewable Energy Directive (RED). In this article, we analyse the effectiveness of the sustainability criteria for climate change mitigation and biodiversity conservation. We first use a global agriculture and forestry model to investigate environmental effects of the EU member states National Renewable Energy Action Plans (NREAPs) without sustainability criteria. We conclude that these targets would drive losses of 2.2 Mha of highly biodiverse areas and generate 95 Mt CO 2 eq of additional greenhouse gas (GHG) emissions. However, in a second step, we demonstrate that the EU biofuel demand could be satisfied ‘sustainably’ according to RED despite its negative environmental effects. This is because the majority of global crop production is produced ‘sustainably’ in the sense of RED and can provide more than 10 times the total European biofuel demand in 2020 if reallocated from sectors without sustainability criteria. This finding points to a potential policy failure of applying sustainability regulation to a single sector in a single region. To be effective this policy needs to be more complete in targeting a wider scope of agricultural commodities and more comprehensive in its membership of countries.
    Recovery and concentration of phenolic compounds in blood orange juice by membrane operations
    Destani, F. ; Cassano, A. ; Fazio, A. ; Vincken, J.P. ; Gebriele, B. - \ 2013
    Journal of Food Engineering 117 (2013)3. - ISSN 0260-8774 - p. 263 - 271.
    osmotic distillation - antioxidant activity - bioactive compounds - citrus flavonoids - anthocyanins - cancer - evaporation - inhibition - extracts - kinetics
    Cross-flow ultrafiltration (UF) and osmotic distillation (OD) were implemented on laboratory scale to obtain formulations of interest for food and/or pharmaceutical industry starting from the blood orange juice produced in the Calabria region. The freshly squeezed juice, after a depectinization step, was submitted to an UF process in order to recover natural antioxidants, such as hydroxycinnamic acids, hydroxybenzoic acids, flavanones, flavan-3-ols, and anthocyanins. The UF permeate, with an initial total soluble solids (TSS) content of 10.5°Brix, was concentrated by OD up to a final concentration of 61.4°Brix. The performance of both processes was analyzed in terms of productivity (permeate fluxes in UF and evaporation fluxes in OD) and quality of clarified and concentrated samples through the identification and quantization of phenolic compounds. The UF membrane showed a rejection towards the identified phenolic compounds in the range 0.4–6.9% and a little decrease of the TAA (8.2%) was observed in the UF permeate in comparison with the fresh juice. Phenolic compounds were also well preserved in the retentate of the OD process as demonstrated by the constant value of the ratio between the concentration of phenolic compounds in the OD retentate and the concentration of these compounds in the UF permeate stream (in the range 5.54–6.39).
    Comparative analyses of seeds of wild fruits or Rubus and Sambucus species from Southern Italy: fatty acid composition of the oil, total phenolic content, antioxidant and anti-inflammatory properties of the methanolic extracts
    Fazio, A. ; Plastina, P. ; Meijerink, J. ; Witkamp, R.F. ; Gabriele, B. - \ 2013
    Food Chemistry 140 (2013)4. - ISSN 0308-8146 - p. 817 - 824.
    chemical-composition - bioactive compounds - berry fruits - nitric-oxide - capacity - inhibition - anthocyanins - cultivar - disease - health
    Fruit seeds are byproducts from fruit processing. Characterisation of the bioactive compounds present in seeds and evaluation of their potential biological properties is therefore of particular importance in view of a possible valorisation of seeds as a source of health beneficial components. In this work, we have analysed the seeds of Sambucus and Rubus species in order to identify their bioactive components and to determine the antioxidant and anti-inflammatory activities of the extracts. We first analysed their oil content, in order to assess the fatty acid profile and tocopherol content. Moreover, the methanolic extracts of the seeds were analysed for their total phenolic contents and antioxidant capacities. Polyphenols were identified by HPLC–ESI–MS/MS analysis. Furthermore, extracts were evaluated for their inhibitory effects on the production of LPS-induced inflammatory mediators (NO, CCL-20) in RAW 264.7 cells. Our findings show that the methanolic extracts from Rubus seeds have strong antioxidant and anti-inflammatory properties and could therefore represent an attractive source of bioactive compounds for food, cosmetic, or pharmaceutical applications.
    THC reduces the anticipatory nucleus accumbens response to reward in subjects with a nicotine addiction
    Jansma, J.M. ; Hell, H.H. van; Vanderschuren, L.J.M.J. ; Bossong, M.G. ; Jager, G. ; Kahn, R.S. ; Ramsey, N.F. - \ 2013
    Translational Psychiatry 3 (2013). - ISSN 2158-3188 - 10 p.
    endogenous cannabinoid anandamide - increasing monetary reward - endocannabinoid system - drug-addiction - cb1 receptors - brain - dependence - rats - inhibition - humans
    Recent evidence has implicated the endocannabinoid (eCB) system in nicotine addiction. The eCB system also has an important role in reward mechanisms, and nicotine addiction has been associated with aberrant reward processing. Motivated by this evidence, we tested the hypothesis that eCB modulation of reward processing is altered in subjects with a nicotine addiction (NAD). For this purpose, we compared reward-related activity in NAD with healthy controls (HC) in a pharmacological magnetic resonance imaging (MRI) study using ¿9-tetrahydrocannabinol (THC) administration to challenge the eCB system. Eleven HC and 10 NAD participated in a 3-T functional MRI (fMRI) study with a double-blind, cross-over, placebo-controlled design, using a Monetary Incentive Delay (MID) paradigm with three reward levels. Reward activity in the nucleus accumbens (NAcc) and caudate putamen during anticipation and feedback of reward was compared after THC and placebo. fMRI results indicated a significant reduction of reward anticipation activity in the NAcc in NAD after THC administration, which was not present in HC. This is indicated by a significant group by drug by reward interaction. Our data show that THC significantly reduces the NAcc response to monetary reward anticipation in NAD. These results suggest that nicotine addiction is associated with altered eCB modulation of reward processing in the NAcc. This study adds important human data to existing evidence implicating the eCB system in nicotine addiction.
    Chicken dendritic cells are susceptible to highly pathogenic avian influenza viruses which induce strong cytokine responses
    Vervelde, L. ; Reemens, S.S. ; Haarlem, D.A. van; Post, J. ; Claassen, E.A.W. ; Rebel, J.M.J. ; Jansen, C.A. - \ 2013
    Developmental and Comparative Immunology 39 (2013)3. - ISSN 0145-305X - p. 198 - 206.
    ns1 protein - a virus - swine influenza - gene-expression - infection - interferon - activation - pathobiology - recognition - inhibition
    Infection with highly pathogenic avian influenza (HPAI) in birds and mammals is associated with severe pathology and increased mortality. We hypothesize that in contrast to low pathogenicity avian influenza (LPAI) infection, HPAI infection of chicken dendritic cells (DC) induces a cytokine deregulation which may contribute to their highly pathogenic nature. Infection of DC with LPAI H7N1 and H5N2 resulted in viral RNA and NP expression without increase in time, in contrast to HPAI H7N1 and H5N2 mRNA expression. No increase in IFN mRNA was detected after infection with LPAI, but after LPAI H5N2, and not LPAI H7N1, infection the level of bioactive IFNa/ß significantly increased. After HPAI H7N1 and H5N2 infection, significant increases in IL-8, IFN-a, IFN-¿ mRNA expression and in TLR1, 3, and 21 mRNA were observed. This enhanced activation of DC after HPAI infection may trigger deregulation of the immune response as seen during HPAI infection in chickens.
    Effect of ammonia on the anaerobic hydrolysis of cellulose and tributyrin
    Vasconcelos Fernandes, T. ; Keesman, K.J. ; Zeeman, G. ; Lier, J.B. van - \ 2012
    Biomass and Bioenergy 47 (2012). - ISSN 0961-9534 - p. 316 - 323.
    thermophilic digestion - methanogenic sludge - bounded noise - cow manure - kinetics - inhibition - nitrogen - identification - waste
    Ammonia nitrogen is one of the most common inhibitors in the anaerobic digestion of complex wastes containing high concentrations of ammonia like animal manures, blackwater and waste oil from gastronomy. The inhibiting effect of ammonia on methanogenesis has been well established. In contrast, the knowledge on the effect of ammonia on organic matter hydrolysis is rather limited. This study focuses on evaluating the effect of ammonia on the hydrolysis of carbohydrates and lipids, which are commonly found in biomass. Batch digestion of tributyrin and cellulose at varying ammonia concentrations were performed, using biomass adapted to 4.9 g NH4+–N.l-1. From this experimental study it was concluded that total ammonia nitrogen in the range of 2.4–7.8 g NH4+–N.l-1 (283–957 mg NH3–N.l-1) does not inhibit the hydrolysis of tributyrin or cellulose. This result is further confirmed by mathematical analysis of the estimated variation of the first-order hydrolysis constant as a function of the total ammonia concentration.
    Effect of hydrogen and carbon dioxide on carboxylic acids patterns in mixed culture fermentation
    Arslan, D. ; Steinbusch, K.J.J. ; Diels, L. ; Wever, H. De; Buisman, C.J.N. ; Hamelers, H.V.M. - \ 2012
    Bioresource Technology 118 (2012). - ISSN 0960-8524 - p. 227 - 234.
    acidogenic fermentation - biohydrogen production - anaerobic-bacteria - waste-water - fatty-acids - degradation - communities - inhibition - hydrolysis - industrial
    This study investigated the carboxylate spectrum from mixed culture fermentation of three organic waste streams after supplying 2 bar hydrogen and carbon dioxide or a mixture of these two gases to the headspace. Under any modified headspace, propionate production was ceased and butyrate, caproate and the total carboxylate concentrations were higher than in the reactors with N2 headspace (control). Production of one major compound was achieved under hydrogen and carbon dioxide mixed headspace after 4 weeks of incubation. Both the highest acetate concentration (17.4 g COD/l) and the highest fraction (87%) were observed in reactors with mixed hydrogen and carbon dioxide headspace independent of the substrate used. In the control reactor, acetate made up maximum 67% of the total products. For other products, the highest concentration and fraction were seldom observed together. Selective butyrate production reaching a 75% fraction was found under the carbon dioxide headspace on the carbohydrate rich waste.
    A petunia ABC protein controls strigolactone-dependent symbiotic signalling and branching
    Kretzschmar, T. ; Kohlen, W. ; Sasse, J. ; Borghi, L. ; Schlegel, M. ; Bachelier, J.B. ; Reinhardt, D. ; Bours, R.M.E.H. ; Bouwmeester, H.J. ; Martinoia, E. - \ 2012
    Nature 483 (2012)7389. - ISSN 0028-0836 - p. 341 - 344.
    arbuscular-mycorrhizal fungi - medicago-truncatula - auxin transport - abscisic-acid - gene family - arabidopsis - pcr - germination - inhibition - pathway
    Strigolactones were originally identified as stimulators of the germination of root-parasitic weeds1 that pose a serious threat to resource-limited agriculture2. They are mostly exuded from roots and function as signalling compounds in the initiation of arbuscular mycorrhizae3, which are plant–fungus symbionts with a global effect on carbon and phosphate cycling4. Recently, strigolactones were established to be phytohormones that regulate plant shoot architecture by inhibiting the outgrowth of axillary buds5, 6. Despite their importance, it is not known how strigolactones are transported. ATP-binding cassette (ABC) transporters, however, are known to have functions in phytohormone translocation7, 8, 9. Here we show that the Petunia hybrida ABC transporter PDR1 has a key role in regulating the development of arbuscular mycorrhizae and axillary branches, by functioning as a cellular strigolactone exporter. P. hybrida pdr1 mutants are defective in strigolactone exudation from their roots, resulting in reduced symbiotic interactions. Above ground, pdr1 mutants have an enhanced branching phenotype, which is indicative of impaired strigolactone allocation. Overexpression of Petunia axillaris PDR1 in Arabidopsis thaliana results in increased tolerance to high concentrations of a synthetic strigolactone, consistent with increased export of strigolactones from the roots. PDR1 is the first known component in strigolactone transport, providing new opportunities for investigating and manipulating strigolactone-dependent processes.
    The path from beta-Carotene to Carlactone, a Strigolactone-Like Plant Hormone
    Alder, J. ; Jamil, M. ; Marzorati, M. ; Bruno, F. ; Bigler, J. ; Bouwmeester, H.J. ; Beyer, P. ; Al-Babili, S. - \ 2012
    Science 335 (2012)6074. - ISSN 0036-8075 - p. 1348 - 1351.
    cleavage oxygenases - biosynthesis - germination - striga - inhibition - metabolism - orobanche - catalyze - enzymes
    Strigolactones, phytohormones with diverse signaling activities, have a common structure consisting of two lactones connected by an enol-ether bridge. Strigolactones derive from carotenoids via a pathway involving the carotenoid cleavage dioxygenases 7 and 8 (CCD7 and CCD8) and the iron-binding protein D27. We show that D27 is a ß-carotene isomerase that converts all-trans-ß-carotene into 9-cis-ß-carotene, which is cleaved by CCD7 into a 9-cis–configured aldehyde. CCD8 incorporates three oxygens into 9-cis-ß-apo-10'-carotenal and performs molecular rearrangement, linking carotenoids with strigolactones and producing carlactone, a compound with strigolactone-like biological activities. Knowledge of the structure of carlactone will be crucial for understanding the biology of strigolactones and may have applications in combating parasitic weeds.
    Biotrickling filter for the treatment of exhaust air from a pig rearing building: Ammonia removal performance and its fluctuations
    Melse, R.W. ; Ploegaert, J.P.M. ; Ogink, N.W.M. - \ 2012
    Biosystems Engineering 113 (2012)3. - ISSN 1537-5110 - p. 242 - 252.
    nitrous-acid - inhibition - nitrification - operations - gases - odor - nh3
    The removal of ammonia (NH3) by a full scale packed-bed biotrickling filter (packing volume: 3.8 m3; water buffer tank: 20 m3) under fluctuating loading conditions was studied. The unit was operated at an animal house for treatment of exhaust air at an average air contact time of 1.2 s. Continuous long-term ammonia measurements showed average inlet and outlet air concentrations of 14 ppm and 2.4 ppm, respectively, and a removal efficiency of 82%. The average temperature of the water was 16 °C, the pH 6.6, the ammonium concentration 1.9 g N l-1, and the nitrate concentration 1.8 g N l-1; no nitrite was detected. The average ammonia loading and removal rate were 29 and 24 g NH3 m-3 h-1, respectively. A daily and seasonal pattern could be observed in the ammonia removal performance. With increasing outside temperature ammonia loading rate, ammonia removal rate, and ammonia outlet concentration increased, resulting in a net decrease of the ammonia removal efficiency. This phenomenon might be explained by the existence of equilibrium between the ammonia concentration in the outlet air and the concentration of dissolved ammonia in the water, which is influenced by fluctuating air and water temperature. A nitrogen balance indicated that 86% of the removed ammonia-N was discharged or accumulated in the water as ammonium and nitrate, and 5% was emitted as nitrous oxide (N2O). The fluctuating removal patterns that were found suggest that current regulatory performance monitoring practices need to be improved
    Strigolactones affect development in primitive plants. The missing link between plants and arbuscular mycorrhizal fungi?
    Ruyter-Spira, C.P. ; Bouwmeester, H.J. - \ 2012
    New Phytologist 195 (2012)4. - ISSN 0028-646X - p. 730 - 733.
    arabidopsis - inhibition - rice
    A limited set of starch related genes explain several interrelated traits in potato
    Werij, J.S. ; Furrer-Verhorst, M. ; Eck, H.J. van; Visser, R.G.F. ; Bachem, C.W.B. - \ 2012
    Euphytica 186 (2012)2. - ISSN 0014-2336 - p. 501 - 516.
    adp-glucose pyrophosphorylase - physicochemical properties - diploid potato - quality traits - water dikinase - alpha-glucan - amylose-free - tuber - inhibition - synthase
    To understand the molecular basis of potato starch related traits and the underlying starch biosynthesis and degradation, a Quantitative Trait Locus (QTL) analysis in combination with a candidate gene approach was performed. The diploid mapping population C × E, consisting of 249 individuals, was assayed over two consecutive years, for chipping colour, cold induced sweetening, starch content, starch granule size, starch gelling temperature, starch enthalpy, amylose content and degree of starch phosphorylation. QTLs were observed for all traits, except enthalpy on eight out of the twelve potato chromosomes. Several QTLs were found to be consistent over 2 years. Clustering of co-localizing QTLs was observed on some chromosomes, indicating common genetic factors for the different traits. On chromosome 2, Soluble Starch Synthase 2 mapped on the same position as QTLs for starch phosphorylation, starch gelling temperature and amylose content. a-glucan, water dikinase co-localizes on chromosome 5 together with QTLs for starch phosphorylation and cold induced sweetening. Furthermore, the genes coding for two phosphorylases (StPho1a and StPho2) coincide with QTLs for starch gelling temperature, chipping colour and starch granule size on chromosome 2 and a QTL for starch phosphorylation on chromosome 9, respectively. The results suggest allelic variation acting on the genetics of the different traits
    An on-line high performance liquid chromatography-crocin bleaching assay for detection of antioxidants
    Bountagkidou, O. ; Klift, E.J.C. van der; Tsimidou, M.Z. ; Ordoudi, S.A. ; Beek, T.A. van - \ 2012
    Journal of Chromatography. A, Including electrophoresis and other separation methods 1237 (2012). - ISSN 0021-9673 - p. 80 - 85.
    radical scavenging compounds - chemiluminescence detection - natural antioxidants - complex-mixtures - identification - capacity - extracts - inhibition - plant
    An on-line HPLC (high performance liquid chromatography) method for the rapid screening of individual antioxidants in mixtures was developed using crocin as a substrate (i.e. oxidation probe) and 2,2'-azobis(2-amidinopropane dihydrochloride (AAPH)) in phosphate buffer (pH 7.5) as a radical generator. The polyene structure of crocin and AAPH-derived peroxyl radicals resemble the lipidic substrates and radicals found in true food more closely than the popular, albeit artificial, DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS+ (2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonate)) do. After separation by a C18 (octadecyl silica) column and UV (ultraviolet) detection, antioxidative analytes react with peroxyl radicals at 90 °C and the inhibition of crocin oxidation (i.e. bleaching) is detected as a positive peak by an absorbance detector at 440 nm. The method is simple, uses standard instruments and inexpensive reagents. It can be applied for isocratic HPLC runs using mobile phases containing 10–90% organic solvent in water, weak acids or buffers (pH 3.5–8.5). With baseline correction, gradient runs are also feasible. The radical scavenging activity of several natural antioxidants and a green tea extract was studied. After optimisation of conditions such as reagent concentrations and flows, the limit of detection varied from 0.79 to 7.4 ng, depending on the antioxidant. --------------------------------------------------------------------------------
    Interference of flavonoids with enzymatic assays for the determination of free fatty acid and triglyceride levels
    Hoek-van den Hil, E.F. ; Beekmann, K. ; Keijer, J. ; Hollman, P.C.H. ; Rietjens, I. ; Schothorst, E.M. van - \ 2012
    Analytical and Bioanalytical Chemistry 402 (2012)3. - ISSN 1618-2642 - p. 1389 - 1392.
    dietary flavonoids - thyroid peroxidase - quercetin - metabolites - rats - myeloperoxidase - polyphenols - inhibition - oxidation - cells
    Flavonoids are bioactive food compounds with potential lipid-lowering effects. Commercially available enzymatic assays are widely used to determine free fatty acid (FFA) and triglyceride (TG) levels both in vivo in plasma or serum and in vitro in cell culture medium or cell lysate. However, we have observed that various flavonoids interfere with peroxidases used in these enzymatic assays, resulting in incorrect lower FFA and TG levels than actually present. Furthermore, addition of isorhamnetin or the major metabolite of the flavonoid quercetin in human and rat plasma, quercetin-3-O-glucuronide, to murine serum also resulted in a significant reduction of the detected TG levels, while a trend was seen for FFA levels. It is concluded that when applying these assays, vigilance is needed and alternative analytical methods, directly assessing FFA or TG levels, should be used for studying the biological effects of flavonoids on FFA and TG levels.
    Genetic variation in strigolactone production and tillering in rice and its effect on Striga hermonthica infection
    Jamil, M. ; Charnikhova, T. ; Houshyani Hassanzadeh, B. ; Ast, A. van; Bouwmeester, H.J. - \ 2012
    Planta 235 (2012)3. - ISSN 0032-0935 - p. 473 - 484.
    arbuscular mycorrhizal fungi - parasitic plants - germination stimulants - phosphate deficiency - am fungi - sorghum - arabidopsis - signals - auxin - inhibition
    Tillering in cereals is a complex process in the regulation of which also signals from the roots in the form of strigolactones play an important role. The strigolactones are signalling molecules that are secreted into the rhizosphere where they act as germination stimulants for root parasitic plants and hyphal branching factors for arbuscular mycorrhizal fungi. On the other hand, they are also transported from the roots to the shoot where they inhibit tillering or branching. In the present study, the genetic variation in strigolactone production and tillering phenotype was studied in twenty rice varieties collected from all over the world and correlated with S. hermonthica infection. Rice cultivars like IAC 165, IAC 1246, Gangweondo and Kinko produced high amounts of the strigolactones orobanchol, 2'-epi-5-deoxystrigol and three methoxy-5-deoxystrigol isomers and displayed low amounts of tillers. These varieties induced high S. hermonthica germination, attachment, emergence as well as dry biomass. In contrast, rice cultivars such as Super Basmati, TN 1, Anakila and Agee displayed high tillering in combination with low production of the aforementioned strigolactones. These varieties induced only low S. hermonthica germination, attachment, emergence and dry biomass. Statistical analysis across all the varieties confirmed a positive correlation between strigolactone production and S. hermonthica infection and a negative relationship with tillering. These results show that genetic variation in tillering capacity is the result of genetic variation in strigolactone production and hence could be a helpful tool in selecting rice cultivars that are less susceptible to S. hermonthica infection.
    Multivariate toxicity profiles and QSAR modeling of non-dioxin-like PCBs – An investigation of in vitro screening data from ultra-pure congeners
    Stenberg, M. ; Hamers, T. ; Machala, M. ; Fonnum, F. ; Stenius, U. ; Lauye, A.A. ; Duursen, M.B.M. van; Westerink, R.H.S. ; Antunes Fernandes, E.C. ; Andersson, P.L. - \ 2011
    Chemosphere 85 (2011)9. - ISSN 0045-6535 - p. 1423 - 1429.
    polychlorinated biphenyl congeners - risk-assessment - p53 response - rat - inhibition - regression - health - potentiation - exposure - receptor
    The non-dioxin-like PCBs (NDL-PCBs) found in food and human samples have a complex spectrum of adverse effects, but lack a detailed risk assessment. The toxicity profiles of 21 carefully selected PCBs (19 NDL-PCBs) were identified by in vitro screening in 17 different assays on specific endpoints related to neurotoxicity, endocrine disruption and tumor promotion. To ensure that the test results were not affected by polychlorinated dioxins, dibenzofurans or DL-PCB contaminants, the NDL-PCB congeners were thoroughly purified before testing. Principal component analysis (PCA) was used to derive general toxicity profiles from the in vitro screening data. The toxicity profiles indicated different structure–activity relationships (SAR) and distinct mechanisms of action. The analysis also indicated that the NDL-PCBs could be divided into two groups. The first group included generally smaller, ortho-substituted congeners, comprising PCB 28, 47, 51, 52, 53, 95, 100, 101, 104 and 136, with PCB 95, 101 and 136 as generally being most active. The second group comprising PCB 19, 74, 118, 122, 128, 138, 153, 170, 180 and 190 had lower biological activity in many of the assays, except for three endocrine-related assays. The most abundant congeners, PCB 138, 153, 170, 180 and 190, cluster in the second group, and thereby show similar SAR. Two quantitative structure–activity relationship (QSAR) models could be developed that added information to the SAR and could aid in risk assessments of NDL-PCBs. The QSAR models predicted a number of congeners as active and among these e.g., PCB 18, 25, 45 and 49 have been found in food or human samples.
    Virus-induced gene silencing in detached tomatoes and biochemical effects of phytoene desaturase gene silencing
    Romero, I. ; Tikunov, Y.M. ; Bovy, A.G. - \ 2011
    Journal of Plant Physiology 168 (2011)10. - ISSN 0176-1617 - p. 1129 - 1135.
    carotenoid biosynthesis - alpha-tomatine - nicotiana-benthamiana - transgenic plants - fruit - esculeoside - expression - accumulation - lycopersicon - inhibition
    Virus-induced gene silencing (VIGS) is a technology that has rapidly emerged for gene function studies in plants. Many advances have been made in applying this technique in an increasing number of crops. Recently, VIGS has been successfully used to silence genes in tomato fruit through agroinfiltration of fruit attached to the plant. The phytoene desaturase (Pds) gene has been widely used as a reporter gene in VIGS experiments, although little is known about the changes that occur due to its silencing in plants. In this paper, we describe the efficient silencing of the Pds gene through the VIGS approach in detached tomato fruits, which makes the VIGS procedure even more versatile and applicable. After 16 days of agroinfiltration, approximately 75% of the tomatoes showed Pds silencing symptoms, although the distribution of silenced areas was variable among fruits. To study the potential effects caused by Pds silencing in detached tomatoes, carotenoids and other semi-polar secondary metabolites were analyzed using Liquid Chromatography-Mass Spectrometry. In addition, potential differences in primary metabolites were analyzed using Gas Chromatography-Mass Spectrometry. The results indicated that the yellow phenotype observed in Pds-silenced fruit was mainly due to the lack of the red-colored lycopene and therefore to a more pronounced contribution of the yellow-orange carotenoids (lutein, violaxanthin, and zeaxanthin) to the final color of the fruits. Furthermore, the biochemical changes observed in Pds-silenced detached tomatoes suggested that carotenoid and other pathways, e.g. leading to alkaloids and flavonoids, might be affected by the silencing of this reporter gene, and this should be taken into consideration for future experimental designs.
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