Touching the High Complexity of Prebiotic Vivinal Galacto-oligosaccharides Using Porous Graphitic Carbon Ultra-High-Performance Liquid Chromatography Coupled to Mass Spectrometry.

Galacto-oligosaccharides (GOS) are used in infant formula to replace the health effects of human milk oligosaccharides, which appear to be dependent upon the structure of the individual oligosaccharides present. However, a comprehensive overview of the structure-specific effects is still limited as a result of the high structural complexity of GOS. In this study, porous graphitic carbon (PGC) was used as the stationary phase during ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS).

Ethyl tert-butyl ether (EtBE) degradation by an algal-bacterial culture obtained from contaminated groundwater.

EtBE is a fuel oxygenate that is synthesized from (bio)ethanol and fossil-based isobutylene, and replaces the fossil-based MtBE. Biodegradation of EtBE to harmless metabolites or end products can reduce the environmental and human health risks after accidental release. In this study, an algal-bacterial culture enriched from contaminated groundwater was used to (i) assess the potential for EtBE degradation, (ii) resolve the EtBE degradation pathway and (iii) characterize the phylogenetic composition of the bacterial community involved in EtBE degradation in contaminated groundwater.

Lipid polymorphism in chloroplast thylakoid membranes - as revealed by P-NMR and time-resolved merocyanine fluorescence spectroscopy.

Chloroplast thylakoid membranes contain virtually all components of the energy-converting photosynthetic machinery. Their energized state, driving ATP synthesis, is enabled by the bilayer organization of the membrane. However, their most abundant lipid species is a non-bilayer-forming lipid, monogalactosyl-diacylglycerol; the role of lipid polymorphism in these membranes is poorly understood.

Glyceollins and dehydroglyceollins isolated from soybean act as SERMs and ER subtype-selective phytoestrogens.

Seven prenylated 6a-hydroxy-pterocapans and five prenylated 6a,11a-pterocarpenes with different kinds of prenylation were purified from an ethanolic extract of fungus-treated soybean sprouts. The activity of these compounds toward both human estrogen receptors (hERα and hERβ) was determined in a yeast bioassay and the activity toward hERα was additionally tested in an U2-OS based hERα CALUX bioassay. In the yeast bioassay, compounds with chain prenylation showed in general an agonistic mode of action toward hERα, whereas furan and pyran prenylation led to an antagonistic mode of action.

Production of butyrate from lysine and the Amadori product fructoselysine by a human gut commensal.

Human intestinal bacteria produce butyrate, which has signalling properties and can be used as energy source by enterocytes thus influencing colonic health. However, the pathways and the identity of bacteria involved in this process remain unclear. Here we describe the isolation from the human intestine of Intestinimonas strain AF211, a bacterium that can convert lysine stoichiometrically into butyrate and acetate when grown in a synthetic medium.

Involvement of a Hydrophobic Pocket and Helix 11 in Determining the Modes of Action of Prenylated Flavonoids and Isoflavonoids in the Human Estrogen Receptor.

Six prenylated (iso)flavonoids were purified from a licorice root extract and subjected to competition experiments with six commercially available (iso)flavonoids. The agonistic and antagonistic activities of these compounds towards both hERα (human estrogen receptor alpha) and hERβ were determined. Differences in the modes of action (agonist or antagonist) were observed for the various compounds tested.

Level and position of substituents in cross-linked and hydroxypropylated sweet potato starches using nuclear magnetic resonance spectroscopy.

Sweet potato starch was cross-linked using sodium trimetaphosphate and hydroxypropylated using propylene oxide. The level and position of phosphorus and hydroxypropyl groups within cross-linked and hydroxypropylated sweet potato starch was investigated by phosphorus and proton nuclear magnetic resonance spectroscopy ((31)P, (1)H NMR). The cross-linking reaction produced monostarch monophosphate and distarch monophosphate in a molar ratio of 1:1.

Enzyme resistant feruloylated xylooligomer analogues from thermochemically treated corn fiber contain large side chains, ethyl glycosides and novel sites of acetylation.

In order to use corn fiber as a source for bioethanol production the enzymatic hydrolysis of the complex glucuronoarabinoxylans present has to be improved. Several oligosaccharides present in the supernatant of mild acid pretreated and enzymatically saccharified corn fiber that resist the current available enzymes were (semi)purified for structural analysis by NMR or ESI-MS(n). The structural features of 21 recalcitrant oligosaccharides are presented.

The structure of an alternative wall teichoic acid produced by a Lactobacillus plantarum WCFS1 mutant contains a 1,5-linked poly(ribitol phosphate) backbone with 2-α-D-glucosyl substitutions.

A tagF1-tagF2 deletion mutant of Lactobacillus plantarum lacks poly(glycerol phosphate) polymerase activity required for glycerol-type wall teichoic acid (WTA) biosynthesis. The mutant activates an alternative genetic locus, tarIJKL, encoding the enzymes for nucleotide activation and incorporation of ribitol in the WTA backbone polymer. This alternative ribitol-type WTA backbone and its repeating unit were isolated and characterized by HPAEC, UPLC-MS, NMR spectroscopy, and MALDI-TOF MS, using synthetic molecules as references.

Novel surface-active oligofructose fatty acid mono-esters by enzymatic esterification.

This article describes the synthesis of a series of oligofructose monoesters with fatty acids of different chain length (C8, C12, C16 and C18) to obtain food-grade surfactants with a range of amphiphilicity. Reactions were performed in a mixture of DMSO/Bu(t)OH (10/90 v/v) at 60°C and catalysed by immobilised Candida antarctica lipase B. MALDI-TOF-MS analysis showed that the crude reaction products were mixtures of unmodified oligofructose and mostly mono-esters.

Development and validation of a confirmative LC-MS/MS method for the determination of ß-exotoxin thuringiensin in plant protection products and selected greenhouse crops.

Bacterial products based on Bacillus thuringiensis are registered in many countries as plant protection products (PPPs) and are widely used as insecticides and nematocides. However, certain B. thuringiensis strains produce harmful toxins and are therefore not allowed to be used as PPPs.

New insights into an ancient antibrowning agent: formation of sulfophenolics in sodium hydrogen sulfite-treated potato extracts.

The effect of sodium hydrogen sulfite (S), used as antibrowning agent, on the phenolic profile of potato extracts was investigated. This extract was compared to one obtained in the presence of ascorbic acid (A). In the presence of A, two major compounds were obtained, 5-O-caffeoylquinic acid (5-CQA) and 4-O-caffeoyl quinic acid.

Proof of principle for the synthesis of hydroxy-aryl esters of glycosidic polyols and non-reducing oligosaccharides with subsequent enzymatic coupling to a tyrosine-containing tripeptide.

To enable enzymatic coupling of saccharides to proteins, several di- and trisaccharides were hydroxy-arylated using anhydrous transesterification with methyl 3-(4-hydroxyphenyl)propionate, catalyzed by potassium carbonate. This transesterification resulted in the attachment of up to 3 hydroxy-aryl units per oligosaccharide molecule, with the monosubstituted product being by far the most abundant. The alkaline reaction conditions, however, resulted in a partial breakdown of reducing sugars.

Branched arabino-oligosaccharides isolated from sugar beet arabinan.

Sugar beet arabinan consists of an alpha-(1,5)-linked backbone of L-arabinosyl residues, which can be either single or double substituted with alpha-(1,2)- and/or alpha-(1,3)-linked L-arabinosyl residues. Neutral branched arabino-oligosaccharides were isolated from sugar beet arabinan by enzymatic degradation with mixtures of pure and well-defined arabinohydrolases from Chrysosporium lucknowense followed by fractionation based on size and analysis by MALDI-TOF MS and HPAEC. Using NMR analysis, two main series of branched arabino-oligosaccharides have been identified, both having an alpha-(1,5)-linked backbone of L-arabinosyl residues.

Production of novel antioxidative phenolic amides through heterologous expression of the plant's chlorogenic acid biosynthesis genes in yeast.

Phenolic esters like chlorogenic acid play an important role in therapeutic properties of many plant extracts. We aimed to produce phenolic esters in baker's yeast, by expressing tobacco 4CL and globe artichoke HCT. Indeed yeast produced phenolic esters.

An intracellular pH gradient in the anammox bacterium Kuenenia stuttgartiensis as evaluated by 31P NMR.

The cytoplasm of anaerobic ammonium oxidizing (anammox) bacteria consists of three compartments separated by membranes. It has been suggested that a proton motive force may be generated over the membrane of the innermost compartment, the "anammoxosome". 31P nuclear magnetic resonance (NMR) spectroscopy was employed to investigate intracellular pH differences in the anammox bacterium Kuenenia stuttgartiensis.

Profiling human gut bacterial metabolism and its kinetics using [U-13C]glucose and NMR.

This study introduces a stable-isotope metabolic approach employing [U-(13)C]glucose that, as a novelty, allows selective profiling of the human intestinal microbial metabolic products of carbohydrate food components, as well as the measurement of the kinetics of their formation pathways, in a single experiment. A well-established, validated in vitro model of human intestinal fermentation was inoculated with standardized gastrointestinal microbiota from volunteers. After culture stabilization, [U-(13)C]glucose was added as an isotopically labeled metabolic precursor.

Isolation, characterization, and surfactant properties of the major triterpenoid glycosides from unripe tomato fruits.

Various triterpenoid glycosides were extracted from whole unripe tomato fruits ( Lycopersicon esculentum cv. Cedrico), using aqueous 70% (v/v) ethanol to study their surfactant properties. Cation-exchange chromatography using a Source 15S column and subsequent semipreparative HPLC using an XTerra RP18 were employed to purify individual triterpenoid glycosides from the extract.

On the transition between a heterogeneous and homogeneous corona in mixed polymeric micelles.

Two-dimensional NMR and small-angle neutron scattering experiments were performed on comicelles of poly(N-methyl-2-vinyl pyridinium iodide)-block-poly(ethylene oxide), P2MVP-b-PEO, and poly(acrylic acid)-block-poly(acryl amide), PAA-b-PAAm, in aqueous solutions to study whether a transition between a heterogeneous (Janus-type) and homogeneous corona can be observed upon a variation of parameters that are anticipated to affect the miscibility of the PEO and PAAm coronal blocks. Investigated were the effect of a salt-induced decrease in micellar aggregation number, P agg for 1 View Article and Find Full Text PDF

Temperature responsive complex coacervate core micelles with a PEO and PNIPAAm corona.

In aqueous solutions at room temperature, poly( N-methyl-2-vinyl pyridinium iodide)- block-poly(ethylene oxide), P2MVP 38- b-PEO 211 and poly(acrylic acid)- block-poly(isopropyl acrylamide), PAA 55- b-PNIPAAm 88 spontaneously coassemble into micelles, consisting of a mixed P2MVP/PAA polyelectrolyte core and a PEO/PNIPAAm corona. These so-called complex coacervate core micelles (C3Ms), also known as polyion complex (PIC) micelles, block ionomer complexes (BIC), and interpolyelectrolyte complexes (IPEC), respond to changes in solution pH and ionic strength as their micellization is electrostatically driven. Furthermore, the PNIPAAm segments ensure temperature responsiveness as they exhibit lower critical solution temperature (LCST) behavior.

Transport and compartmentation of phosphite in higher plant cells--kinetic and P nuclear magnetic resonance studies.

Phosphite (Phi, H(2)PO(3)(-)), being the active part of several fungicides, has been shown to influence not only the fungal metabolism but also the development of phosphate-deficient plants. However, the mechanism of phosphite effects on plants is still widely unknown. In this paper we analysed uptake, subcellular distribution and metabolic effects of Phi in tobacco BY-2 cells using in vivo(31)P nuclear magnetic resonance ((31)P-NMR) spectroscopy.

Malic acid production by Saccharomyces cerevisiae: engineering of pyruvate carboxylation, oxaloacetate reduction, and malate export.

Malic acid is a potential biomass-derivable "building block" for chemical synthesis. Since wild-type Saccharomyces cerevisiae strains produce only low levels of malate, metabolic engineering is required to achieve efficient malate production with this yeast. A promising pathway for malate production from glucose proceeds via carboxylation of pyruvate, followed by reduction of oxaloacetate to malate.

Phase behavior of phosphatidylglycerol in spinach thylakoid membranes as revealed by 31P-NMR.

Non-bilayer lipids account for about half of the total lipid content in chloroplast thylakoid membranes. This lends high propensity of the thylakoid lipid mixture to participate in different phases which might be functionally required. It is for instance known that the chloroplast enzyme violaxanthin de-epoxidase (VDE) requires a non-bilayer phase for proper functioning in vitro but direct evidence for the presence of non-bilayer lipid structures in thylakoid membranes under physiological conditions is still missing.

Identification of glucose-fermenting bacteria present in an in vitro model of the human intestine by RNA-stable isotope probing.

16S rRNA-based stable isotope probing (SIP) and nuclear magnetic resonance (NMR) spectroscopy-based metabolic profiling were used to identify bacteria fermenting glucose under conditions simulating the human intestine. The TIM-2 in vitro model of the human intestine was inoculated with a GI tract microbiota resembling that of the small intestine, to which subsequently 4, 20 or 40 mM of [U-(13)C]-glucose were added. RNA was extracted from lumen samples after 0 (control), 1, 2 and 4 h and subjected to density-gradient ultracentrifugation.