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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    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.
    Effects of acid-extrusion on the degradability of maize distillers dried grain with solubles in pigs
    Vries, S. de; Pustjens, A.M. ; Rooijen, C. van; Kabel, M.A. ; Hendriks, W.H. ; Gerrits, W.J.J. - \ 2014
    Journal of Animal Science 92 (2014)12. - ISSN 0021-8812 - p. 5496 - 5506.
    dietary fiber - growing pigs - amino-acid - reactive lysine - nonstarch polysaccharides - nutritional implications - gastrointestinal-tract - ethanol-production - large-intestine - wheat bran
    Commonly used feed processing technologies are not sufficient to affect recalcitrant non-starch polysaccharides (NSP) such as arabinoxylans present in maize distillers dried grain with solubles (DDGS). Instead, hydrothermal treatments combined with acid catalysts might be more effective to modify these NSP. The objective of this experiment was to investigate the effects of hydrothermal maleic acid treatment (acid-extrusion) on the degradability of maize DDGS in growing pigs. It was hypothesized that acid-extrusion modifies DDGS cell wall architecture and, thereby, increases fermentability of NSP. Two diets, containing either 40% (wt/wt) unprocessed or acid-extruded DDGS, were restrictedly fed to groups of gilts (n = 11, with 4 pigs per group; initial mean BW: 20.8 ± 0.2 kg) for 18 d and performance and digestibility were analyzed. Acid-extrusion tended to decrease apparent ileal digestibility (AID) of CP (~3 percentage units, P = 0.063) and starch (~1 percentage unit, P = 0.096). Apparent digestibility of CP and starch measured at the mid colon (2 percentage units, P = 0.030 for CP and 0.3 percentage units, P <0.01 for starch) and total tract (ATTD; 3 percentage units, P <0.01 for CP and 0.2 percentage units, P = 0.024 for starch) were lower for the acid-extruded diet compared with the control diet. Hindgut disappearance was, however, not different between diets indicating that reduced CP and starch digestibility were mainly due to decreased AID. Acid-extrusion tended to increase AID of NSP (6 percentage units, P = 0.092) and increased digestibility of NSP measured at the mid colon (6 percentage units, P <0.01), whereas, hindgut disappearance and ATTD of NSP did not differ between diets. Greater NSP digestibility was mainly due to greater digestibility of arabinosyl, xylosyl, and glucosyl residues, indicating that both arabinoxylan and cellulose degradability were affected by acid-extrusion. In conclusion, these results show that acid-extrusion did not improve degradation of DDGS for growing pigs. Although acid-extrusion seemed to facilitate more rapid degradation of NSP and shifted fermentation to more proximal gastrointestinal segments, total extent of NSP degradation was not affected. More than 35% of the NSP from DDGS remained undegraded, independent of technological processing. Enzyme technologies that specifically target ester-linked acetyl, feroloyl, or coumaroyl groups were identified to be of interest for future research.
    Influence of water availability on the enzymatic hydrolysis of proteins
    Butré, C.I. ; Wierenga, P.A. ; Gruppen, H. - \ 2014
    Process Biochemistry 49 (2014)11. - ISSN 1359-5113 - p. 1903 - 1912.
    substrate-inhibition - functional-properties - ionic-strength - amino-acid - hydration - nmr - macromolecules - mechanism - kinetics - protease
    The overall rate of enzymatic protein hydrolysis decreases with increasing protein concentration (0.1–30% (w/v)) at constant enzyme/substrate ratio. To understand the role of water, the amount of available water was expressed as the ratio between free and bound water and experimentally determined from water activity and T2 relaxation time (NMR) measurements. At low protein concentrations a large excess of water is present (1.5 × 106 water molecules per protein molecule at 0.1% (w/v) whey protein isolate (WPI), but only 3984 at 30% (w/v) WPI. Assuming that 357 molecules of water are needed for full hydration of the protein, these values correspond to a 4280 and 11 times excess of water, showing that at 30% (w/v) WPI the amount of water becomes limited. At the same time, only a small decrease was observed in water activity (1.00–0.997 for 0.1–30% (w/v) WPI), and an increase of bound water measured by NMR (
    Isolation and characterization of H7N9 avian influenza A virus from humans with respiratory diseases in Zhejiang, China.
    Zhang, Y. ; Mao, H. ; Yan, J. ; Zhang, L. ; Sun, Y. ; Wang, X. ; Chen, Y. ; Lu, Y. ; Chen, E. ; Lv, H. ; Gong, L. ; Li, Z. ; Gao, J. ; Xu, C. ; Feng, Y. ; Ge, Q. ; Xu, B. ; Xu, F. ; Yang, Z. ; Zhao, C. ; Han, J. ; Koch, G. ; Li, H. ; Shu, Y.L. ; Chen, Z. - \ 2014
    Virus Research 189 (2014). - ISSN 0168-1702 - p. 158 - 164.
    human infection - amino-acid - poultry - host - transmission - substitution - pathogenesis - determinant - adaptation - polymerase
    In 2013, the novel reassortant avian-origin influenza A (H7N9) virus was reported in China. Through enhanced surveillance, infection by the H7N9 virus in humans was first identified in Zhejiang Province. Real-time reverse-transcriptase-polymerase-chain-reaction (RT-PCR) was used to confirm the infection. Embryonated chicken eggs were used for virus isolation from pharyngeal swabs taken from infected human patients. The H7N9 isolates were first identified by the hemagglutination test and electron microscopy, then used for whole genome sequencing. Bioinformatics software was used to construct the phylogenetic tree and for computing the mean rate of evolution of the HA gene in H7Nx and NA in HxN9. Two novel H7N9 avian influenza A viruses (A/Zhejiang/1/2013 and A/Zhejiang/2/2013) were isolated from the positive infection cases. Substitutions were found in both Zhejiang isolates and were identified as human-type viruses. All phylogenetic results indicated that the novel reassortant in H7N9 originated in viruses that infected birds. The sequencing and phylogenetic analysis of the whole genome revealed the mean rate of evolution of the HA gene in H7NX to be 5.74E-3 (95% Highest posterior density: 3.8218E-3 to 7.7873E-3) while the NA gene showed 2.243E-3 (4.378E-4 to 3.79E-3) substitutions per nucleotide site per year. The novel reassortant H7N9 virus was confirmed by molecular methods to have originated in poultry, with the mutations occurring during the spread of the H7N9 virus infection. Live poultry markets played an important role in whole H7N9 circulation.
    Felinine excretion in domestic cat breeds: a preliminary investigation
    Hagen-Plantinga, E.A. ; Bosch, G. ; Hendriks, W.H. - \ 2014
    Journal of Animal Physiology and Animal Nutrition 98 (2014)3. - ISSN 0931-2439 - p. 491 - 496.
    felis-catus - urinary felinine - amino-acid - testosterone - dogs
    The aim of this study was to determine possible differences in felinine excretion between domesticated cat breeds. For this purpose, urine was collected from a total of 83 privately owned entire male cats from eight different breeds in the Netherlands during the period of November 2010 till November 2011. In the collected samples, free felinine and creatinine concentrations were measured. Free felinine concentrations were expressed relative to the urinary creatinine concentration to compensate for possible variations in renal output. The mean (±SD) felinine:creatinine (Fel:Cr) ratio as measured over all cats was 0.702 (±0.265). Both the Abyssinian and Sphynx breeds showed the highest Fel:Cr ratio (0.878 ± 0.162 and 0.878 ± 0.341 respectively) which significantly differed from the ratios of the British Shorthairs (0.584 ± 0.220), Birmans (0.614 ± 0.266), Norwegian Forest cats (0.566 ± 0.296) and Siberian cats (0.627 ± 0.124). The Fel:Cr ratios of the Persians (0.792 ± 0.284) and Ragdolls (0.673 ± 0.256) showed no statistical difference with either of the other breeds. A significant proportion of the observed variation between the different feline breeds could be explained by hair growth, as both hair growth and felinine production compete for available cysteine. Shorthaired and hairless cat breeds generally showed a higher Fel:Cr ratio compared to longhaired cat breeds, with the exception of Persian cats. Further research is warranted to more closely study the effect of hair growth on felinine production.
    What makes protein indigestible from tissue-related, cellular, and molecular aspects?
    Becker, P.M. ; Yu, P.Q. - \ 2013
    Molecular Nutrition & Food Research 57 (2013)10. - ISSN 1613-4125 - p. 1695 - 1707.
    dried distillers grains - amino-acid - enzymatic hydrolysate - nutritional quality - lotus-corniculatus - condensed tannins - maillard reaction - oxidizing lipids - insect cuticle - food proteins
    This paper gives an insight into key factors, which impair enzymatic protein digestion. By nature, some proteins in raw products are already poorly digestible because of structural peculiarities, or due to their occurrence in plant cytoplasmic organelles or in cell membranes. In plant-based protein, molecular and structural changes can be induced by genetic engineering, even if protein is not a target compound class of the genetic modification. Other proteins only become difficult to digest due to changes that occur during the processing of proteinaceous products, such as extruding, boiling, or acidic or alkaline treatment. The utilization of proteinaceous raw materials in industrial fermentations can also have negative impacts on protein digestibility, when reused as fermentation by-products for animal nutrition, such as brewers' grains. After consumption, protein digestion can be impeded in the intestine by the presence of antinutritional factors, which are ingested together with the food or feedstuff. It is concluded that the encircling matrix, but also molecular, chemical, and structural peculiarities or modifications to amino acids and proteins obstruct protein digestion by common proteolytic enzymes in humans and animals.
    Evaluation of a Commercial Enzyme Linked Immunosorbent Assay (ELISA) for the Determination of the Neurotoxin BMAA in Surface Waters
    Faassen, E.J. ; Beekman-Lukassen, W.D. ; Lurling, M. - \ 2013
    PLoS ONE 8 (2013)6. - ISSN 1932-6203 - 7 p.
    methylamino-l-alanine - amino-acid - mass-spectrometry - cyanobacteria - chromatography - seeds - guam
    The neurotoxin ß-N-methylamino-L-alanine (BMAA) is suspected to play a role in Alzheimer’s disease, Parkinson’s disease and amyotrophic lateral sclerosis. Because BMAA seems to be produced by cyanobacteria, surface waters are screened for BMAA. However, reliable analysis of BMAA requires specialized and expensive equipment. In 2012, a commercial enzyme-linked immunosorbent assay (ELISA) for determination of BMAA in surface waters was released. This kit could enable fast and relatively cheap screening of surface waters for BMAA. The objective of this study was to determine whether the BMAA ELISA kit was suitable for the determination of BMAA concentrations in surface waters. We hypothesised that the recovery of spiked samples was close to 100% and that the results of unspiked sample analysis were comparable between ELISA and liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. However, we found that recovery was higher than 100% in most spiked samples, highest determined recovery was over 400%. Furthermore, the ELISA gave a positive signal for nearly each tested sample while no BMAA could be detected by LC-MS/MS. We therefore conclude that in its current state, the kit is not suitable for screening surface waters for BMAA.
    The Maillard reaction and pet food processing: effects on nutritive value and pet health
    Rooijen, C. van; Bosch, G. ; Poel, A.F.B. van der; Wierenga, P.A. ; Alexander, L. ; Hendriks, W.H. - \ 2013
    Nutrition Research Reviews 26 (2013)2. - ISSN 0954-4224 - p. 130 - 148.
    glycation end-products - distillers dried grains - age-related-changes - slope-ratio assay - available lysine - amino-acid - diabetes-mellitus - extrusion-cooking - model systems - growing-pigs
    The Maillard reaction, which can occur during heat processing of pet foods or ingredients, is known to reduce the bioavailability of essential amino acids such as lysine due to the formation of early and advanced Maillard reaction products (MRP) that are unavailable for utilisation by the body. Determination of the difference between total and reactive lysine by chemical methods provides an indication of the amount of early MRP present in foods, feeds and ingredients. Previous research reported that the difference between total and reactive lysine in pet foods can be up to 61·8 %, and foods for growing dogs may be at risk of supplying less lysine than the animal may require. The endogenous analogues of advanced MRP, advanced glycation endproducts, have been associated with age-related diseases in humans, such as diabetes and impaired renal function. It is unknown to what extent advanced MRP are present in pet foods, and if dietary MRP can be associated with the development of diseases such as diabetes and impaired renal function in pet animals. Avoidance of ingredients with high levels of MRP and processing conditions known to favour the Maillard reaction may be useful strategies to prevent the formation of MRP in manufactured pet food. Future work should further focus on understanding the effects of ingredient choice and processing conditions on the formation of early and advanced MRP, and possible effects on animal health.
    Rapid emergence of a virulent PB2 E627K variant during adaptation of highly pathogenic avian influenza H7N7 virus to mice
    Jong, M.C. de; Stockhofe-Zurwieden, N. ; Verheij, E.S. ; Boer-Luijtze, E.A. de; Ruiter, S.J.M. ; Leeuw, O.S. de; Cornelissen, A.H.M. - \ 2013
    Virology journal 10 (2013). - ISSN 1743-422X
    a virus - amino-acid - viral polymerase - molecular-basis - h5n1 viruses - host-range - mouse lung - humans - determinants - transmission
    Background Highly pathogenic avian influenza (HPAI) viruses pose a potential human health threat as they can be transmitted directly from infected poultry to humans. During a large outbreak of HPAI H7N7 virus among poultry in The Netherlands in 2003, bird to human transmission was confirmed in 89 cases, of which one had a fatal outcome. Methods To identify genetic determinants of virulence in a mammalian host, we passaged an avian H7N7/03 outbreak isolate in mouse lungs and evaluated the phenotype of the mouse-adapted variant in animal models and in vitro. Results Three passages in mouse lungs were sufficient to select a variant that was highly virulent in mice. The virus had a MLD50 that was >4.3 logs lower than that of its non-lethal parental virus. Sequence analysis revealed a single mutation at position 627 in PB2, where the glutamic acid was changed to a lysine (E627K). The mouse-adapted virus has this mutation in common with the fatal human case isolate. The virus remained highly pathogenic for chickens after its passage in mice. In ferrets, the mouse-adapted virus induced more severe disease, replicated to higher titers in the lower respiratory tract and spread more efficiently to systemic organs compared with the parental virus. In vitro, the PB2 E627K mutation had a promoting effect on virus propagation in mammalian, but not in avian cells. Conclusions Our results show that the E627K mutation in PB2 alone can be sufficient to convert an HPAI H7N7 virus of low virulence to a variant causing severe disease in mice and ferrets. The rapid emergence of the PB2 E627K mutant during mouse adaptation and its pathogenicity in ferrets emphasize the potential risk of HPAI H7N7 viruses for human health.
    Reactants encapsulation and Maillard Reaction
    Troise, A.D. ; Fogliano, V. - \ 2013
    Trends in Food Science and Technology 33 (2013). - ISSN 0924-2244 - p. 63 - 74.
    model dough systems - in-water emulsions - n-epsilon-carboxymethyllysine - polyunsaturated fatty-acids - ascorbic-acid - acrylamide formation - lipid oxidation - high-pressure - amino-acid - microencapsulated ingredients
    In the last decades many efforts have been addressed to the control of Maillard Reaction products in different foods with the aim to promote the formation of compounds having the desired color and flavor and to reduce the concentration of several potential toxic molecules. Encapsulation, already applied in food industry for different purposes, can be used as a strategy to get the controlled release of some compounds promoting the Maillard Reaction development in order to mitigate the formation of some undesired compounds. In this review the underneath reaction mechanism, the activity of various reactants, the encapsulation strategies and some possible applications in food processing were discussed highlighting the potentialities of encapsulated ingredients in the modulation of Maillard Reaction.
    Processing Technologies and Cell Wall Degrading Enzymes To Improve Nutritional Value of Dried Distillers Grain with Solubles for Animal Feed: an in Vitro Digestion Study
    Vries, S. de; Pustjens, A.M. ; Kabel, M.A. ; Salazar-Villanea, S. ; Hendriks, W.H. ; Gerrits, W.J.J. - \ 2013
    Journal of Agricultural and Food Chemistry 61 (2013)37. - ISSN 0021-8561 - p. 8821 - 8828.
    amino-acid - dietary fiber - growing pigs - nonstarch polysaccharides - corn - fermentation - gas - ingredients - ethanol - digestibility
    Currently, the use of maize dried distillers grain with solubles (DDGS) as protein source in animal feed is limited by the inferior protein quality and high levels of non-starch polysaccharides (NSP). Processing technologies and enzymes that increase NSP degradability might improve digestive utilization of DDGS, enhancing its potential as a source of nutrients for animals. The effects of various combinations of processing technologies and commercial enzyme mixtures on in vitro digestion and subsequent fermentation of DDGS were tested. Wet-milling, extrusion, and mild hydrothermal acid treatment increased in vitro protein digestion but had no effect on NSP. Severe hydrothermal acid treatments, however, effectively solubilized NSP (48–78%). Addition of enzymes did not affect NSP solubilization in unprocessed or processed DDGS. Although the cell wall structure of DDGS seems to be resistant to most milder processing technologies, in vitro digestion of DDGS can be effectively increased by severe hydrothermal acid treatments.
    Construction of a Multifunctional Enzyme Complex via the Strain-Promoted Azide-Alkyne Cycloaddition
    Schoffelen, S. ; Beekwilder, M.J. ; Debets, M.F. ; Bosch, H.J. ; Hest, J.C.M. van - \ 2013
    Bioconjugate Chemistry 24 (2013)6. - ISSN 1043-1802 - p. 987 - 996.
    escherichia-coli - protein fusions - amino-acid - resveratrol - biosynthesis - scaffolds - cascade - organization - metabolism - cells
    Inspired by the multienzyme complexes occurring in nature, enzymes have been brought together in vitro as well. We report a co-localization strategy milder than nonspecific cross-linking, and free of any scaffold and affinity tags. Using non-natural amino acid incorporation, two heterobifunctional linkers, and the strain-promoted azide–alkyne cycloaddition as conjugation reaction, three metabolic enzymes are linked together in a controlled manner. Conjugate formation was demonstrated by size-exclusion chromatography and gel electrophoresis. The multienzyme complexes were further characterized by native mass spectrometry. It was shown that the complexes catalyzed the three-step biosynthesis of piceid in vitro with comparable kinetic behavior to the uncoupled enzymes. The approach is envisioned to have high potential for various biotechnological applications, in which multiple biocatalysts collaborate at low concentrations, in which diffusion may be limited and/or side-reactions are prone to occur
    The gut microbiota elicits a profound metabolic reorientation in the mouse jejunal mucosa during conventionalisation
    Aidy, S. El; Merrifield, C.A. ; Derrien, M. ; Baarlen, P. van; Hooiveld, G.J. ; Levenez, F. ; Dore, J. ; Dekker, J. ; Holmes, E. ; Claus, S.P. ; Reijngoud, D.J. ; Kleerebezem, M. - \ 2013
    Gut 62 (2013). - ISSN 0017-5749 - p. 1306 - 1314.
    inflammatory-bowel-disease - gastric bypass - amino-acid - glutamate - intestine - surgery - mice - biosynthesis - homeostasis - expression
    OBJECTIVE: Proper interactions between the intestinal mucosa, gut microbiota and nutrient flow are required to establish homoeostasis of the host. Since the proximal part of the small intestine is the first region where these interactions occur, and since most of the nutrient absorption occurs in the jejunum, it is important to understand the dynamics of metabolic responses of the mucosa in this intestinal region. DESIGN: Germ-free mice aged 8-10 weeks were conventionalised with faecal microbiota, and responses of the jejunal mucosa to bacterial colonisation were followed over a 30-day time course. Combined transcriptome, histology, (1)H NMR metabonomics and microbiota phylogenetic profiling analyses were used. RESULTS: The jejunal mucosa showed a two-phase response to the colonising microbiota. The acute-phase response, which had already started 1 day after conventionalisation, involved repression of the cell cycle and parts of the basal metabolism. The secondary-phase response, which was consolidated during conventionalisation (days 4-30), was characterised by a metabolic shift from an oxidative energy supply to anabolic metabolism, as inferred from the tissue transcriptome and metabonome changes. Detailed transcriptome analysis identified tissue transcriptional signatures for the dynamic control of the metabolic reorientation in the jejunum. The molecular components identified in the response signatures have known roles in human metabolic disorders, including insulin sensitivity and type 2 diabetes mellitus. CONCLUSION: This study elucidates the dynamic jejunal response to the microbiota and supports a prominent role for the jejunum in metabolic control, including glucose and energy homoeostasis. The molecular signatures of this process may help to find risk markers in the declining insulin sensitivity seen in human type 2 diabetes mellitus, for instance.
    Production of acetone, butanol, and ethanol from biomass of the green seaweed Ulva lactuca
    Wal, H. van der; Sperber, B.L.H.M. ; Houweling-Tan, G.B.N. ; Bakker, R.R.C. ; Brandenburg, W.A. ; Lopez Contreras, Ana - \ 2013
    Bioresource Technology 128 (2013)2013. - ISSN 0960-8524 - p. 431 - 437.
    clostridium-acetobutylicum - dietary fiber - amino-acid - marine - polysaccharides - 1,2-propanediol - fermentation - macroalgae - strains - rigida
    Green seaweed Ulva lactuca harvested from the North Sea near Zeeland (The Netherlands) was characterized as feedstock for acetone, ethanol and ethanol fermentation. Solubilization of over 90% of sugars was achieved by hot-water treatment followed by hydrolysis using commercial cellulases. A hydrolysate was used for the production of acetone, butanol and ethanol (ABE) by Clostridium acetobutylicum and Clostridium beijerinckii. Hydrolysate-based media were fermentable without nutrient supplementation. C. beijerinckii utilized all sugars in the hydrolysate and produced ABE at high yields (0.35 g ABE/g sugar consumed), while C. acetobutylicum produced mostly organic acids (acetic and butyric acids). These results demonstrate the great potential of U. lactuca as feedstock for fermentation. Interestingly, in control cultures of C. beijerinckii on rhamnose and glucose, 1,2 propanediol was the main fermentation product (9.7 g/L).
    Metabolomic and elemental profiling of melon fruit quality as affected by genotype and environment
    Bernillon, S. ; Biais, B. ; Deborde, C. ; Maucort, M. ; Cabasson, C. ; Gibon, Y. ; Hansen, T. ; Husted, S. ; Vos, R.C.H. de; Mumm, R. ; Jonker, H. ; Ward, J.L. ; Miller, S.J. ; Baker, J.M. ; Burger, J. ; Tadmor, Y. ; Beale, M.H. ; Schjoerring, J.K. ; Schaffer, A. ; Rolin, D. ; Hall, R.D. ; Moing, A. - \ 2013
    Metabolomics 9 (2013)1. - ISSN 1573-3882 - p. 57 - 77.
    cucumis-melo - tomato fruit - chemical-composition - functional genomics - plant metabolomics - mass-spectrometry - aroma volatiles - nitrate ratio - grape berry - amino-acid
    Melon (Cucumis melo L.) is a global crop in terms of economic importance and nutritional quality. The aim of this study was to explore the variability in metabolite and elemental composition of several commercial varieties of melon in various environmental conditions. Volatile and non-volatile metabolites as well as mineral elements were profiled in the flesh of mature fruit, employing a range of complementary analytical technologies. More than 1,000 metabolite signatures and 19 mineral elements were determined. Data analyses revealed variations related to factors such as variety, growing season, contrasting agricultural management practices (greenhouse vs. field with or without fruit thinning) and planting date. Two hundred and ninety-one analytes discriminated two contrasting varieties, one from the var. inodorous group and the other from the var. cantaloupensis group. Two hundred and eighty analytes discriminated a short shelf-life from a mid-shelf-life variety within the var. cantaloupensis group. Three hundred and twenty-seven analytes discriminated two seasons, and two hundred and fifty-two analytes discriminated two contrasting agricultural management practices. The affected compound families greatly depended on the factor studied. The compositional variability of identified or partially identified compounds was used to study metabolite and mineral element co-regulation using correlation networks. The results confirm that metabolome and mineral element profiling are useful diagnostic tools to characterize the quality of fruits cultivated under commercial conditions. They can also provide knowledge on fruit metabolism and the mechanisms of plant response to environmental modifications, thereby paving the way for metabolomics-guided improvement of cultural practices for better fruit quality.
    Untargeted Metabolic Quantitative Trait Loci Analyses Reveal a Relationship between Primary Metabolism and Potato Tuber Quality
    Carreno Quintero, N. ; Acharjee, A. ; Maliepaard, C.A. ; Bachem, C.W.B. ; Mumm, R. ; Bouwmeester, H.J. ; Visser, R.G.F. ; Keurentjes, J.J.B. - \ 2012
    Plant Physiology 158 (2012)3. - ISSN 0032-0889 - p. 1306 - 1318.
    chromatography-mass spectrometry - arabidopsis-thaliana - starch degradation - late blight - amino-acid - enzymatic discoloration - biochemical networks - introgression lines - genetic genomics - candidate genes
    Recent advances in -omics technologies such as transcriptomics, metabolomics, and proteomics along with genotypic profiling have permitted dissection of the genetics of complex traits represented by molecular phenotypes in nonmodel species. To identify the genetic factors underlying variation in primary metabolism in potato (Solanum tuberosum), we have profiled primary metabolite content in a diploid potato mapping population, derived from crosses between S. tuberosum and wild relatives, using gas chromatography-time of flight-mass spectrometry. In total, 139 polar metabolites were detected, of which we identified metabolite quantitative trait loci for approximately 72% of the detected compounds. In order to obtain an insight into the relationships between metabolic traits and classical phenotypic traits, we also analyzed statistical associations between them. The combined analysis of genetic information through quantitative trait locus coincidence and the application of statistical learning methods provide information on putative indicators associated with the alterations in metabolic networks that affect complex phenotypic traits.
    Effects of drying temperature and time of a canine diet extruded with a 4 or 8 mm die on physical and nutritional quality indicators
    Tran, Q.D. ; Hendriks, W.H. ; Poel, A.F.B. van der - \ 2011
    Animal Feed Science and Technology 165 (2011)3. - ISSN 0377-8401 - p. 258 - 264.
    digestible reactive lysine - protein-quality - amino-acid - extrusion - foods - starch - spaghetti - bioassay - wheat
    Two factorial experiments (4 temperatures × 2 durations) were carried out to test the effect of drying variables on nutritional and physical quality indicators of extruded canine diets produced using a 4 and 8 mm die (kibble size). The diet was extruded using a single screw extruder at 130 °C and 300 g moisture/kg. The drying temperatures used were 80, 120, 160 and 200 °C and each diet was dried to 90 or 60 g moisture/kg diet (drying duration). Drying of the diets was conducted in draught-forced ovens and each sample was analysed for dry matter, nitrogen, amino acids (including reactive lysine) and fatty acid content. Hardness and specific density of the tested diets were not affected by drying temperature or time. Kibble durability was affected (P
    Proteinase K resistant material in ARR/VRQ sheep brain affected with classical scrapie is composed mainly of VRQ prion protein
    Jacobs, J.G. ; Bossers, A. ; Rezaei, H. ; Keulen, L. Van; McCutcheon, S. ; Sklaviadis, T. ; Lantier, I. ; Berthon, P. ; Lantier, F. ; Zijderveld, F.G. van; Langeveld, J.P.M. - \ 2011
    Journal of Virology 85 (2011)23. - ISSN 0022-538X - p. 12537 - 12546.
    bovine spongiform encephalopathy - creutzfeldt-jakob-disease - susceptibility-linked polymorphisms - straussler-scheinker disease - in-vitro conversion - allelic variants - amino-acid - monoclonal-antibodies - natural scrapie - prp
    Classical scrapie is a prion disease in sheep and goats. In sheep, susceptibility to disease is genetically influenced by single amino acid substitutions. Genetic breeding programs aimed at enrichment of arginine-171 (171R) prion protein (PrP), the so called ARR allele, in the sheep population have demonstrated to be effective in reducing the occurrence of classical scrapie in the field. Understanding the molecular basis for this reduced prevalence would serve the assessment of ARR-adaptation. The prion formation mechanism and conversion of PrP from the normal form (PrPC) to scrapie associated form (PrPSc) could play a key-role in this process. Therefore, we investigated whether the ARR allele substantially contributes to scrapie prion formation in naturally infected heterozygous 171Q/R animals. Two methods were applied to brain tissue of 171Q/R heterozygous sheep with natural scrapie to determine the relative amount of the 171R PrP fraction in PrPres, the proteinase K-resistant PrPSc core. An antibody test differentiating between 171Q and 171R PrP fragments showed that PrPres mostly was composed of the 171Q allelotype. Furthermore using a novel tool for prion research, endoproteinase Lys-C digested PrPres yielded substantial amounts of non-glycosylated and mono-glycosylated 114-188 PrP fragment. Following two-dimensional gel electrophoresis only marginal amounts (
    Effects of the cyanobacterial neurotoxin B-N-methylamino-L-alamine (BMAA) on the survival, mobility and reproduction of Daphnia magna
    Lürling, M.F.L.L.W. ; Faassen, E.J. ; Eenennaam, J.S. van - \ 2011
    Journal of Plankton Research 33 (2011)2. - ISSN 0142-7873 - p. 333 - 342.
    per-capita rate - amino-acid - neurodegenerative disease - microcystis-aeruginosa - phenotypic plasticity - toxic cyanobacteria - population-growth - pulex - water - guam
    In short-term tests and chronic life table assays, Daphnia magna was exposed to the cyanobacterial neurotoxic non-protein amino acid ß-N-methylamino-l-alanine (BMAA). BMAA was not acutely lethal to Daphnia (LC50–48h > 10 000 µg L-1), but reduced mobility (IC50–48h 40 µg L-1) and affected life history characteristics. Animals showed a tendency to later age at first reproduction, larger size at first reproduction, smaller clutch size and lower population growth rates with higher concentrations of BMAA. Animals that had been kept in either food-free medium or were fed the green alga Scenedemus obliquus with BMAA accumulated BMAA in their tissue. The highest measured bioconcentration factors were 275 in adult D. magna and 3821 in their neonates. This bioconcentration of the neurotoxic BMAA in D. magna suggests that these animals may be an important vector of BMAA in the pelagic food web
    Novel, Fully Biobased Semicrystalline Polyamides
    Jasinska, L. ; Villani, M. ; Es, D.S. van; Klop, E. ; Rastogi, S. ; Koning, C.E. - \ 2011
    Macromolecules 44 (2011)9. - ISSN 0024-9297 - p. 3458 - 3466.
    folded lamellar crystals - x-ray-diffraction - brill transition - amino-acid - bioanalogous polymers - nylon-6 6 - behavior - amide)s - temperature - polycondensation
    Novel, semicrystalline polyamides and co(polyamides) were synthesized from biobased sebacic acid (SA), 2,5-diamino-2,5-dideoxy-1,4;3,6-dianhydroiditol (diaminoisoidide, DAII) as well as from 1,4-diaminobutane (DAB), also known as putrescine in nature. Low molecular weight polyamides were obtained by melt polycondensation of the salts based on these monomers or by interfacial polycondensation. In order to increase their molecular weights the polyamide prepolymers were submitted to a solid state polymerization (SSP) process. The chemical structure of the polymers was confirmed by 2D NMR correlation spectra (COSY), heteronuclear multiple-bond correlation spectra (HMBC) and by FT-IR spectroscopy. In the present work, FT-IR and X-ray techniques were used as a tool for the investigation of the crystal structure of the polymers after SSP. The X-ray diffractograms of the polyamides point to crystals containing both 4.10- and DAII.10-based repeat units. Because of the presence of diaminoisoidide residues the synthesized fully renewable products exhibit tunable polarities and melting points. Since most commercial polyamides have a much higher melting point than their end application requires, especially for fiber applications, this simple adaption can result in a significant reduction of energy consumption during processing.
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