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A combined intake of cooked sweet potato and fried onion in humans was found to suppress the increase of plasma quercetin metabolite concentration. Experiments using rat β-glucosidase indicated that excess carbohydrate digestion products, especially glucose-containing saccharides, interfere with the deglycosylation of quercetin glucosides during intestinal epithelial uptake. Combined meals of sweet potato and onion may lower the bioavailability of onion quercetin glucosides. [ABSTRACT FROM AUTHOR]

Norathyriol is an aglycone of a xanthonoid C -glycoside mangiferin that possesses different bioactive properties useful for humans compared to mangiferin. Mangiferin is more readily available in nature than norathyriol; thus, efficient mangiferin conversion into norathyriol is desirable. There are a few reports regarding mangiferin C -deglycosylation because of the C–C bond resistance toward acid, alkaline, and enzyme hydrolysis. In this study, we isolated a mangiferin-deglycosylating bacterium strain KM7-1 from the mouse intestine. 16S rDNA sequencing indicated that KM7-1 belongs to the Bacillus genus. Compared to the taxonomically similar bacteria, the growth characteristic of facultative anaerobic and thermophilic resembled, yet only Bacillus sp. KM7-1 was able to convert mangiferin into norathyriol. Resting cells of Bacillus sp. KM7-1 obtained from aerobic cultivation at 50 °C showed high norathyriol formation from 1 m  m of mangiferin. Norathyriol formation can be conducted either under aerobic or anaerobic conditions, and the reaction depended on time and bacterial amount. [ABSTRACT FROM AUTHOR]

Free N-glycans (FNGs) are ubiquitous in growing plants. Further, acidic peptide:N-glycanase is believed to be involved in the production of plant complex-type FNGs (PCT-FNGs) during the degradation of dysfunctional glycoproteins. However, the distribution of PCT-FNGs in growing plants has not been analyzed. Here, we report the occurrence of PCT-FNGs in the xylem sap of the stem of the tomato plant. Abbreviations: RP-HPLC: reversed-phase HPLC; SF-HPLC: size-fractionation HPLC; PA-: pyridylamino; PCT: plant complex type; Hex: hexose; HexNAc: N-acetylhexosamine; Pen: pentose; Deoxyhex: deoxyhexose; Man: D-mannose; GlcNAc: N-acetyl-D-glucosamine; Xyl: D-xylose; Fuc: L-fucose; Lea: Lewis a (Galβ1-3(Fucα1-4)GlcNAc); PCT: plant complex type; M3FX: Manα1-6(Manα1-3)(Xylβ1-2)Manβ1-4GlcNAcβ1-4(Fucα1-3)GlcNAc-PA; GN2M3FX: GlcNAcβ1-2Manα1-6(GlcNAcβ1-2Manα1-3)(Xylβ1-2)Manβ1-4GlcNAcβ1-4(Fucα1-3)GlcNAc-PA; (Lea)1GN1M3FX: Galβ1-3(Fucα1-4)GlcNAc1-2 Manα1-6(GlcNAcβ1-2Manα1-3)(Xylβ1-2)Manβ1-4GlcNAcβ1-4(Fucα1-3)GlcNAc-PA or GlcNAc1-2Manα1-6(Galβ1-3(Fucα1-4)GlcNAc1-2Manα1-3)(Xylβ1-2)Manβ1-4GlcNAcβ1-4(Fucα1-3)GlcNAc-PA. [ABSTRACT FROM AUTHOR]

Isoflavones are usually found in nature in their glycosilated or methylated forms, and should be hydrolysed to become bioavailable and physiologically active. The deglycosylation of isoflavone C -glycosides and O -glycosides and the demethylase activity were studied in a selection of lactic acid bacteria (LAB) and bifidobacteria by assessing the degree of transformation of the pure precursor compounds, daidzin, genistin, puerarin, formononetin and biochanin A into daidzein or genistein. Only one Bifidobacterium strain and two Enterococcus strains hydrolysed the C -glycosidic bond of puerarin, while deglycosylation of O -glycosides daidzin and genistin was observed in all the tested strains. Demethylation of biochanin A and formononetin was observed in the most of LAB and bifidobacteria. Besides, the subsequent metabolites dihydrodaidzein and dihydrogenistein where produced by many of the strains via daidzein and genistein. In this work, we show the potential of LAB and bifidobacteria as part of functional foods because of their ability to transform plant isoflavones into their bioactive forms. [ABSTRACT FROM AUTHOR]

Dystroglycan ( DG), composed of α and β subunits, belongs to the dystrophin-associated glycoprotein complex. α- DG is an extracellular matrix protein that undergoes a complex post-translational glycosylation process. The bifunctional glycosyltransferase like-acetylglucosaminyltransferase (LARGE) plays a crucial role in the maturation of α- DG, enabling its binding to laminin. We have already structurally analyzed the N-terminal region of murine α-DG (α- DG-Nt) and of a pathological single point mutant that may affect recognition of LARGE, although the structural features of the potential interaction between LARGE and DG remain elusive. We now report on the crystal structure of the wild-type human α- DG-Nt that has allowed us to assess the reliability of our murine crystallographic structure as a α- DG-Nt general model. Moreover, we address for the first time both structures in solution. Interestingly, small-angle X-ray scattering ( SAXS) reveals the existence of two main protein conformations ensembles. The predominant species is reminiscent of the crystal structure, while the less populated one assumes a more extended fold. A comparative analysis of the human and murine α- DG-Nt solution structures reveals that the two proteins share a common interdomain flexibility and population distribution of the two conformers. This is confirmed by the very similar stability displayed by the two orthologs as assessed by biochemical and biophysical experiments. These results highlight the need to take into account the molecular plasticity of α- DG-Nt in solution, as it can play an important role in the functional interactions with other binding partners. [ABSTRACT FROM AUTHOR]

Marein, flavanomarein and taxifolin-7-O-β-D-glucopyranoside (TDG) are functional compounds in capitula of Coreopsis tinctoria (CCT). This study demonstrated the above glycosides could be partially deglycosylated to okanin, isookanin and taxifolin, respectively, in cell free extracts from rat and human small intestine, human colon, but not from stomach and cecum. Okanin and isookanin mainly occurred as glucuronide conjugates; whereas taxifolin was in sulfate in rat plasma. The exposures of the glycosides and aglycones were positively correlated with the dosages of CCT extract in rats after oral administration. The aglycones but not glycosides were detected in the plasma of healthy volunteers after intake of CCT (2.5 g/50 kg) water solution. In conclusion, marein, flavanomarein and TDG could be deglycosylated to respective aglycones in gastrointestinal tracts, which could be absorbed and biotransformed to glucuronide or sulfate conjugates. The results will help us to better understand the function and functional components of CCT in vivo . [ABSTRACT FROM AUTHOR]

This work deals with the capacity of various anthocyanin derivatives to insert lipid bilayer membrane. Malvidin-3- O -glucoside was studied in its various charge forms (flavylium cation, neutral and anionic quinonoid bases) as well as its deglycosylated, hydrated and conjugated derivatives. Based on molecular dynamics (MD) and COSMOmic simulations, membrane partitioning and crossing were evaluated. The free MD simulations provided molecular description of all intermolecular interactions driving penetration and orientation of these polyphenols in a model of DOPC lipid bilayer. Most of the derivatives are theoretically predicted to insert rather deep in the membrane i.e., embedded in between lipid chains, therefore being prone to scavenge both the initiation and propagation stages of lipid peroxidation. Here we also stress again the importance of the method used to evaluate atomic charge distribution to allow a correct description of membrane penetration. [ABSTRACT FROM AUTHOR]

Carbohydrate moieties of different glycoproteins, such as cross-reactive carbohydrate determinants (CCDs) and galactose α-1,3-galactose, can induce IgE reactivity with varied clinical significance. In this study, the possible participation of glycan from wheat gliadin, with respect to its IgE-binding capacity, was investigated in children with food allergies to wheat. Total IgE and wheat-specific IgE quantification, documentation of history, and/or oral food challenge (OFC) were performed for 52 children. Subjects with positive wheat-specific IgE were characterized as the symptomatic group, never-exposed group, or asymptomatic group. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and glycan detection in gliadin were performed. IgE binding to gliadin and deglycosylated gliadin was measured by immunoblotting and ELISA. Gliadin-specific IgE was detected and correlated with wheat-specific IgE in the symptomatic, never-exposed, and asymptomatic groups. The glycan range overlapped significantly with the gliadin range. Deglycosylation of gliadin reduced the allergenicity of gliadin. In gliadin, the allergenicity of the glycan portion was greater in the symptomatic group than in the never-exposed and asymptomatic groups. We conclude that N-glycan in gliadin might exhibit allergenicity as a possible carbohydrate epitope in wheat allergy in children. [ABSTRACT FROM AUTHOR]

Abstract: Pregnant women who develop preeclampsia exhibit higher circulating levels of the soluble VEGF receptor-1 (sFlt-1). Recent findings suggest that soluble Flt-1 may contribute to the pathogenesis of preeclampsia by binding and neutralizing vascular endothelial growth factors (VEGF) and placental growth factor (PlGF). Existing literature identifies sFlt-1 as a 100kDa glycoprotein, a product of an mRNA splice variant. We hypothesized that sFlt-1 expression may be more complex with multiple variants of sFlt-1 as well as multiple sources during normal pregnancy and preeclampsia. Using a combination of affinity purification of sFlt-1 by heparin-agarose and epitope specific antibodies, we performed Western blot analysis with epitope specific antibodies for sFlt-1. Plasma of preeclamptic women exhibits significantly higher amounts of a novel 145kDa variant of sFlt-1, along with the 100kDa isoform. We identified sFlt-1 variants in the conditioned medium from placental explant cultures that are hypoxia responsive with varying sizes, including 185, 145,100 and 60kDa forms, as well as antigenicity. The 145kDa was similar in antigenicity to the 100kDa found in plasma whereas the 185 and 60kDa sFlt-1 demonstrated different epitopes. Deglycosylation studies also confirm that there are multiple sFlt-1 polypeptides. Co-immunoprecipitation with VEGF suggests that these different sFlt isoforms can bind VEGF and therefore, may be of functional importance. Finally, comparison of sFlt-1 in the conditioned medium obtained from cultured cytotrophoblasts, peripheral blood mononuclear cells (PBMCs) and human uterine microvascular cells (HUtMVECs) exhibit mainly the100kDa sFlt-1. Collectively these data suggest the presence of multiple isoforms of sFlt-1 in the circulation of women with preeclampsia as well as in uncomplicated pregnancies and the possibility of multiple sources. Placental hypoxia may contribute to sFlt-1 over expression but other regulatory mechanisms cannot be ruled out. [Copyright &y& Elsevier]

Abstract: Two anaerobic bacteria involved in the conversion of the plant lignan secoisolariciresinol diglucoside were isolated from faeces of a healthy male adult. The first isolate, strain SDG-Mt85-3Db, was a mesophilic strictly anaerobic Gram-positive helically coiled rod. Based on 16S r RNA gene sequence analysis, its nearest relatives were Clostridium cocleatum (96.7% similarity) and Clostridium ramosum (96.6%). In contrast to these species, the isolate was devoid of alpha-galactosidase and -glucosidase and did not grow on maltose, melibiose, raffinose, rhamnose and trehalose. The hypothesis that strain SDG-Mt85-3Db represents a new bacterial species of the Clostridium cluster XVIII was confirmed by DNA–DNA hybridisation experiments. The G+C content of DNA of strain SDG-Mt85-3Db (30.7±0.8mol%) was comparable with that of Clostridium butyricum, the type species of the genus Clostridium. The name Clostridium saccharogumia is proposed for strain SDG-Mt85-3Db (=DSM 17460T=CCUG 51486T). The second isolate, strain ED-Mt61/PYG-s6, was a mesophilic strictly anaerobic Gram-positive regular rod. Based on 16S rRNA gene sequence analysis, its nearest relatives were Clostridium amygdalinum (93.3%), Clostridium saccharolyticum (93.1%) and Ruminococcus productus (93.0%). The isolate differed from these species in its ability to dehydrogenate enterodiol. It also possessed alpha-arabinosidase and -galactosidase and had a higher G+C content of DNA (48.0mol%). According to these findings, it is proposed to create a novel genus, Lactonifactor, and a novel species, Lactonifactor longoviformis, to accommodate strain ED-Mt61/PYG-s6. The type strain is DSM 17459T (=CCUG 51487T). [Copyright &y& Elsevier]

Introduction: We recently demonstrated that serum lipid levels are altered in growth restricted fetuses (IUGR) . Objectives: We now aimed to analyse the proteome profile of umbilical cord blood in order to gain a greater understanding about metabolic changes in IUGR fetuses. Methods: umbilical cord blood serum samples of IUGR (n =15) and of gestational age matched controls (CN; n =15) were subjected to fractionation by affinity chromatography using a bead system with hydrophobic interaction capabilities. So prepared protein mixtures were forwarded to MALDI–TOF mass spectrometric profiling. Assignment of ion signals in the mass spectra to specific proteins was substantiated by SDS–PAGE in conjunction with peptide mass fingerprint analysis. Concentrations of proteins of interest were additionally measured by ELISA. Statistical estimations were performed by Student’s t-test and calculation of Spearman’s correlation coefficient. Results: MALDI mass spectra showed on average more than 60 protein ion signals between m/z 4000 and 25,000. The six best differentiating ion signals were found at m/z 8205, m/z 8766, m/z 13,945, m/z 15,129, m/z 15,308, and m/z 16,001. One of the constituent of this proteome signature is the deglycosylated form of apolipoprotein C-III, apo C-III0 (8766 m/z) that is known to prevent triglycerides from catabolism. While total Apo CIII concentration tended to be decreased (IUGR 22.54μg/mL SD 10.25. CN 29.9μg/mL SD 15.46. p =0.1355) calculated Apo C-III0 concentration levels has been found to be more abundant in the IUGR cord blood serum samples (IUGR 1.99μg/mL SD 0.85. CN 1.15μg/mL SD 0.55. p<0.0001). Moreover, fetal triglycerid levels were significantly increased in IUGR (IUGR 16.7mg/dL SD 7.58. CN 56.5mg/dL SD 49.92. p-value after log transformation =0.0008)and apo C-III0 was highly correlated to fetal triglyceride levels (rho=0.694). Conclusion: Using mass spectrometric approaches we successfully developed an IUGR specific proteome signature derived from human umbilical cord blood samples. Most interesting the deglycosylated form of the apolipoprotein C-III (apoC-III0) was found to be significantly increased in IUGR and thus might lead to reduced triglyceride catabolism. This observation is in agreement with the known observation of triglyceride levels being increased in IUGR fetuses. Our results indicate that subtle alterations in protein glycosylation need to be considered for improving our understanding of the pathomechanisms in IUGR. [Copyright &y& Elsevier]