106,083 research outputs found
Comparative structural characterization of 7 commercial galacto-oligosaccharide (GOS) products
No full textMany β-galactosidase enzymes convert lactose into a mixture of galacto-oligosaccharides (GOS) when incubated under the right conditions. Recently, the composition of commercial Vivinal GOS produced by Bacillus circulans β-galactosidase was studied in much detail in another study by van Leeuwen et al. As a spin-off of this study, we used the developed analytical strategy for the evaluation of 6 anonymous commercial GOS products, in comparison with Vivinal GOS. These GOS products were first subjected to HPLC-SEC, calibrated HPAEC-PAD profiling (glucose units in relation to a malto-oligosaccharide ladder), and 1D (1)H NMR spectroscopy. For a more detailed analysis and support of the conclusions based on the initial analysis, the GOS products were separated into DP-pure subpools on Bio-Gel P-2 (MALDI-TOF-MS analysis), which were subjected to calibrated HPAEC-PAD profiling and (1)H NMR analysis. Unidentified peaks from different GOS products, not present in Vivinal GOS, were isolated for detailed structural characterization. In this way, the differences between the various GOS products in terms of DP distribution and type of glycosidic linkages were established. A total of 13 new GOS structures were characterized, adding structural-reporter-group signals and HPAEC-PAD based glucose unit G.U. values to the analytical toolbox. The newly characterized products enhance the quality of the database with GOS structures up to DP4. The combined data provide a firm basis for the rapid profiling of the GOS products of microbial β-galactosidase enzymes
Galactooligosaccharide (GOS) Reduces Branched Short-Chain Fatty Acids, Ammonium, and pH in a Short-Term Colonic Fermentation Model
No full textPrebiotics beneficially affect the gut microbiome. Bimuno®, a prebiotic supplement containing galactooligosaccharides (GOS), has multiple demonstrated prebiotic effects. Using short-term colonic incubations, the influence of GOS on the colonic microbiota of three healthy human adults was evaluated. Colonic reactors inoculated with fecal samples were untreated (blank) or supplemented with GOS. pH, gas pressure, short-chain fatty acids (SCFAs), lactic acid, branched SCFAs, ammonium, and microbial community composition were evaluated at 0 h, 6 h, 24 h, and 48 h. pH decreased and gas pressure increased (+29.01 kPa) with GOS treatment versus blank. Total SCFA (+22.4 mM), acetate (+14.1 mM), propionate (+5.5 mM), and butyrate (+5.8 mM) were higher for GOS than blank. Acetate and propionate production were highest earlier in the experiment, while butyrate production was highest between 24 h and 48 h. With GOS, lactic acid production increased between 0 h and 6 h (+14.4 mM) followed by apparent consumption. Levels of branched SCFAs and ammonium were low with GOS and reduced versus blank (respectively, −2.1 mM and −256.0 mg/L). GOS significantly increased the relative abundance of Bifidobacterium longum (LDA = 4; p = 0.006), and significantly increased the absolute abundance of Bifidobacteriaceae (p < 0.001), Lactobacillaceae (p < 0.05), Bifidobacterium adolescentis (LDA = 4.5; p < 0.001), and Bifidobacterium ruminantium (LDA= 3.2; p = 0.01). This in vitro model demonstrated the prebiotic potential of GOS as supplementation resulted in increased beneficial bacteria, SCFA, and lactic acid and decreased branched SCFA, pH, and ammonium
H-1 NMR analysis of the lactose/beta-galactosidase-derived galacto-oligosaccharide components of Vivinal (R) GOS up to DP5
No full textVivinal (R) GOS is a galacto-oligosaccharide (GOS) product, prepared from lactose by incubation with Bacillus circulans beta-galactosidase (EC 3.2.1.23). This complex mixture of saccharides with degree of polymerization (DP) between 1 and 8 is generally applied in infant nutrition. Here, a detailed structural description of the commercial product up to the DP5 level is given. First, Vivinal (R) GOS was subjected to DP analysis using HPLC-SEC (Rezex RSO-01 oligosaccharide Ag+ column) and H-1 NMR analysis. Then, the product was fractionated on Bio-Gel P-2, and the obtained fractions were pooled according to DP, as indicated by MALDI-TOF-MS analysis. Finally, fractions of single DP, as well as their subfractions obtained by HPAEC-PAD on CarboPac PA-1, were analyzed by 1D/2D H-1/C-13 NMR spectroscopy and linkage analysis. In total, over 40 structures, providing a structural coverage of over 99% of the product, have been characterized. Detailed H-1 and C-13 NMR data, as well as G.U. values (glucose units; malto-oligosaccharide ladder) on CarboPac PA-1 of all oligosaccharides are included. (C) 2014 Elsevier Ltd. All rights reserved
Cumulative production of BCFA and ammonia after 72 h of addition of apple fiber, sugar beet pectin, GOS or lactulose.
No full text<p>Cumulative production of BCFA and ammonia after 72 h of addition of apple fiber, sugar beet pectin, GOS or lactulose.</p
Sun-synchronous highly elliptical orbits using low-thrust propulsion
No full textDue to restrictions within the current architecture of the global observing system (GOS), space-based remote sensing of Earth suffers from an acute data-deficit over the critical polar-regions. Currently, observation of high-latitude regions is conducted using composite images from spacecraft in geostationary (GEO) and low-Earth orbits (LEOs) [1]. However, the oblique viewing geometry from GEO-based systems to latitudes above around 55 deg [2] and the insufficient temporal resolution of spacecraft in LEO means there is currently no source of continuous imagery for polar-regions obtained with a data refresh rate of less than 15 minutes, as is typically available elsewhere for meteorological observations
Continuous Packed Bed Reactor with Immobilized β-Galactosidase for Production of Galactooligosaccharides (GOS)
No full textThe β-galactosidase from Bacillus circulans was covalently attached to aldehyde-activated (glyoxal) agarose beads and assayed for the continuous production of galactooligosaccharides (GOS) in a packed-bed reactor (PBR). The immobilization was fast (1 h) and the activity of the resulting biocatalyst was 97.4 U/g measured with o-nitrophenyl-β-d-galactopyranoside (ONPG). The biocatalyst showed excellent operational stability in 14 successive 20 min reaction cycles at 45 °C in a batch reactor. A continuous process for GOS synthesis was operated for 213 h at 0.2 mL/min and 45 °C using 100 g/L of lactose as a feed solution. The efficiency of the PBR slightly decreased with time; however, the maximum GOS concentration (24.2 g/L) was obtained after 48 h of operation, which corresponded to 48.6% lactose conversion and thus to maximum transgalactosylation activity. HPAEC-PAD analysis showed that the two major GOS were the trisaccharide Gal-β(1→4)-Gal-β(1→4)-Glc and the tetrasaccharide Gal-β(1→4)-Gal-β(1→4)-Gal-β(1→4)-Glc. The PBR was also assessed in the production of GOS from milk as a feed solution. The stability of the bioreactor was satisfactory during the first 8 h of operation; after that, a decrease in the flow rate was observed, probably due to partial clogging of the column. This work represents a step forward in the continuous production of GOS employing fixed-bed reactors with immobilized β-galactosidases
Comparative evaluation of H&H and WFNS grading scales with modified H&H (sans systemic disease): A study on 1000 patients with subarachnoid hemorrhage
No full textThe comparative studies on grading in subarachnoid hemorrhage (SAH) had several limitations such as the unclear grading of Glasgow Coma Scale 15 with neurological deficits in World Federation of Neurosurgical Societies (WFNS), and the inclusion of systemic disease in Hunt and Hess (H&H) scales. Their differential incremental impacts and optimum cut-off values for unfavourable outcome are unsettled. This is a prospective comparison of prognostic impacts of grading schemes to address these issues. SAH patients were assessed using WFNS, H&H (including systemic disease), modified H&H (sans systemic disease) and followed up with Glasgow Outcome Score (GOS) at 3 months. Their performance characteristics were analysed as incremental ordinal variables and different grading scale dichotomies using rank-order correlation, sensitivity, specificity, positive predictive value, negative predictive value, Youden’s J and multivariate analyses. A total of 1016 patients were studied. As univariate incremental variable, H&H sans systemic disease had the best negative rank-order correlation coefficient (−0.453) with respect to lower GOS (p < 0.001). As univariate dichotomized category, WFNS grades 3–5 had the best performance index of 0.39 to suggest unfavourable GOS with a specificity of 89% and sensitivity of 51%. In multivariate incremental analysis, H&H sans systemic disease had the greatest adjusted incremental impact of 0.72 (95% confidence interval (CI) 0.54–0.91) against a lower GOS as compared to 0.6 (95% CI 0.45–0.74) and 0.55 (95% CI 0.42–0.68) for H&H and WFNS grades, respectively. In multivariate categorical analysis, H&H grades 4–5 sans systemic disease had the greatest impact on unfavourable GOS with an adjusted odds ratio of 6.06 (95% CI 3.94–9.32). To conclude, H&H grading sans systemic disease had the greatest impact on unfavourable GOS. Though systemic disease is an important prognostic factor, it should be considered distinctly from grading. Appropriate cut-off values suggesting unfavourable outcome for H&H and WFNS were 4–5 and 3–5, respectively, indicating the importance of neurological deficits in addition to level of consciousness
Ljubov´ čevengurskich brat´ev i sester: reprezentacija telesnosti v romane A. Platonova
No full textGünther H. Ljubov´ čevengurskich brat´ev i sester: reprezentacija telesnosti v romane A. Platonova. In: Zvereva GI, ed. Reprezentacii telesnosti. Moskva: Rossijskij Gos. Gumanitarnyj Univ.; 2003: 97-111
Safety of the extension of use of galacto-oligosaccharides (GOS) as a novel food in food for special medical purposes pursuant to Regulation (EU) 2015/2283
No full textFollowing a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on the extension of use of galacto-oligosaccharides (GOS) as a novel food (NF) pursuant to Regulation (EU) 2015/2283. The NF (β-GOS) is produced from milk lactose using a β-galactosidase derived from Bifidobacterium bifidum and it is proposed to be used in food for special medical purposes (FSMP). The target population is the general population from 4 years of age onwards. GOS produced according to the same production process are already authorised and included in the EU Union list of novel foods. The applicant stated that the maximum daily intake from the use in FSMP is 8.25 g GOS. GOS are already authorised for use in food supplements up to a daily dose of 16.2 g. FSMP containing GOS are not intended to be used if food supplements containing GOS are consumed on the same day. The information provided on the proposed use levels and anticipated intake does not raise safety concerns. The Panel concludes that the proposed extension of use of GOS in FSMP is safe under the proposed conditions of use
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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