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.

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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.
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