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Varga M.,National Agricultural Research and Innovation Center | Varga M.,Cereal Research Non Profit Ltd. | Berkesi O.,University of Szeged | Darula Z.,Hungarian Academy of Sciences | And 2 more authors.
Phytochemistry | Year: 2016

The brown to black coloration found in plants is due to the melanins, which have been relatively poorly investigated among the plant pigments. The aim of this work was to study the dark pigment extracted from the black oat hull with respect to composition and structure. Ultraviolet-visible (UV-Vis) spectroscopy, electron paramagnetic resonance (EPR) spectroscopy, matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) and Fourier transform infrared (FT-IR) spectroscopy were applied for the characterization of the pigment. UV-Vis spectroscopy revealed that the extracted material displays a broadband, structureless absorption profile a common feature of melanins. MALDI-TOF MS measurements demonstrated that oat melanin is a homopolymer built up from . p-coumaric acid and consists mainly of low molecular weight (527-1499 Da) oligomers of 3-9 monomer units. The tetramer oligomer proved to be dominant. The results of the FT-IR analysis indicated that oat melanin is a fully conjugated aromatic system containing tetrasubstituted aromatic rings linked by C. C coupling. The . in vitro preparation of melanin from . p-coumaric acid by horseradish peroxidase was performed for comparison. The resulting polymer consisted of oligomers of 4-9 monomer units similarly to those in oat melanin. However, the building blocks proved to be connected to each other via C. O. C linkages in contrast with the C. C linkages in oat melanin. © 2016 Elsevier Ltd. Source


Csorba T.,John Innes Center | Csorba T.,National Agricultural Research and Innovation Center | Questa J.I.,John Innes Center | Sun Q.,John Innes Center | And 2 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2014

Long noncoding RNAs (lncRNAs) have been proposed to play important roles in gene regulation. However, their importance in epigenetic silencing and how specificity is determined remain controversial. We have investigated the cold-induced epigenetic switching mechanism involved in the silencing of Arabidopsis thaliana FLOWERING LOCUS C (FLC), which occurs during vernalization. Antisense transcripts, collectively named COOLAIR, are induced by prolonged cold before the major accumulation of histone 3 lysine 27 trimethylation (H3K27me3), characteristic of Polycomb silencing. We have found that COOLAIR is physically associated with the FLC locus and accelerates transcriptional shutdown of FLC during cold exposure. Removal of COOLAIR disrupted the synchronized replacement of H3K36 methylation with H3K27me3 at the intragenic FLC nucleation site during the cold. Consistently, genetic analysis showed COOLAIR and Polycomb complexes work independently in the cold-dependent silencing of FLC. Our data reveal a role for lncRNA in the coordinated switching of chromatin states that occurs during epigenetic regulation. Source


Guine R.P.F.,Polytechnic Institute of Viseu | Duarte J.,Polytechnic Institute of Viseu | Ferreira M.,Polytechnic Institute of Viseu | Correia P.,Polytechnic Institute of Viseu | And 20 more authors.
Public Health | Year: 2016

Objectives: Because there is scientific evidence that an appropriate intake of dietary fibre should be part of a healthy diet, given its importance in promoting health, the present study aimed to develop and validate an instrument to evaluate the knowledge of the general population about dietary fibres. Study design: The present study was a cross sectional study. Methods: The methodological study of psychometric validation was conducted with 6010 participants, residing in 10 countries from three continents. The instrument is a questionnaire of self-response, aimed at collecting information on knowledge about food fibres. Exploratory factor analysis (EFA) was chosen as the analysis of the main components using varimax orthogonal rotation and eigenvalues greater than 1. In confirmatory factor analysis by structural equation modelling (SEM) was considered the covariance matrix and adopted the maximum likelihood estimation algorithm for parameter estimation. Results: Exploratory factor analysis retained two factors. The first was called dietary fibre and promotion of health (DFPH) and included seven questions that explained 33.94% of total variance (α = 0.852). The second was named sources of dietary fibre (SDF) and included four questions that explained 22.46% of total variance (α = 0.786). The model was tested by SEM giving a final solution with four questions in each factor. This model showed a very good fit in practically all the indexes considered, except for the ratio χ2/df. The values of average variance extracted (0.458 and 0.483) demonstrate the existence of convergent validity; the results also prove the existence of discriminant validity of the factors (r2 = 0.028) and finally good internal consistency was confirmed by the values of composite reliability (0.854 and 0.787). Conclusions: This study allowed validating the KADF scale, increasing the degree of confidence in the information obtained through this instrument in this and in future studies. © 2016 The Royal Society for Public Health. Source


Balazs A.,Szent Istvan University | Krifaton C.,Szent Istvan University | Risa A.,Szent Istvan University | Cserhati M.,Szent Istvan University | And 7 more authors.
International Biodeterioration and Biodegradation | Year: 2014

The aim of this study was to screen microorganisms belonging to Rhodococcus and Cupriavidus genera, for their DHT degrading capability and to select microbes with the best biodetoxification potential. Bioluminescent bioreporters (Saccharomyces cerevisiae BLYAS and BLYR) were successfully used to monitor DHT degradation and the results were confirmed by chemical analysis (GC-MS). Several strains with high potential for DHT biotransformation were selected on the base of analytical method, but bioreporters were able to monitor the samples for bioavailable toxicants and androgenic potential even after substantial degradation. Based on this integrated chemical and biological analysis DHT-degrading microbes, ones that produced minimal toxic products and products with lower androgenic potential could be selected. Out of the selected microbes Rhodococcus pyridinivorans strain AK37 was further investigated by using extracellular extracts of the microbe, which demonstrated a DHT-degradation with the total loss of androgenicity after 9h. Results indicated that the degradation is enzymatic and that the enzymes responsible for the degradation of DHT are extracellular and constitutively produced. © 2014 Elsevier Ltd. Source


Toth A.,National Agricultural Research and Innovation Center | Barna T.,Debrecen University | Szabo E.,Debrecen University | Elek R.,Debrecen University | And 6 more authors.
PLoS ONE | Year: 2016

Thermobifidas are thermotolerant, compost inhabiting actinomycetes which have complex polysaccharide hydrolyzing enzyme systems. The best characterized enzymes of these hydrolases are cellulases from T. fusca, while other important enzymes especially hemicellulases are not deeply explored. To fill this gap we cloned and investigated endomannanases from those reference strains of the Thermobifida genus, which have published data on other hydrolases (T. fusca TM51, T. alba CECT3323, T. cellulosilytica TB100T and T. halotolerans YIM90462T). Our phylogenetic analyses of 16S rDNA and endomannanase sequences revealed that T. alba CECT3323 is miss-classified; it belongs to the T. fusca species. The cloned and investigated endomannanases belong to the family of glycosyl hydrolases 5 (GH5), their size is around 50 kDa and they are modular enzymes. Their catalytic domains are extended by a C-terminal carbohydrate binding module (CBM) oftype2witha23-25 residues long interdomain linker region consisting of Pro, Thr and Glu/Asp rich repetitive tetrapeptide motifs. Their polypeptide chains exhibit high homology, interdomain sequence, which don't show homology to each other, but all of them are built up from 3-6 times repeated tetrapeptide motifs) (PTDP-Tc, TEEP-Tf,DPGT-Th). All of the heterologously expressed Man5A enzymes exhibited activity only on mannan. The pH optima of Man5A enzymes from T. halotolerans, T. cellulosilytica and T. fusca are slightly different (7.0, 7.5 and 8.0, respectively) while their temperature optima span within the range of 70-75°C. The three endomannanases exhibited very similar kinetic performances on LBG-mannan substrate: 0.9-1.7mM of KM and 80-120 1/sec of turnover number. We detected great variability in heat stability at 70°C, which was influenced by the presence of Ca2+. The investigated endomannanases might be important subjects for studying the structure/function relation behind the heat stability and for industrial applications to hemicellulose degradation. © 2016 Tóth et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Source

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