scholarly journals Characterization of a Natural, Stable, Reversible and Colourful Anthocyanidin Network from Sphagnum Moss Based Mainly on the Yellow Trans-Chalcone and Red Flavylium Cation Forms

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 709
Author(s):  
Helge Berland ◽  
Øyvind M. Andersen
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Cell Wall ◽  
Peat Moss ◽  
Sphagnum Moss ◽  
Naturally Occurring ◽  
Two Component ◽  
Colour System ◽  
The Common ◽  
Cis And Trans

Anthocyanins with various functions in nature are one of the most important sources of colours in plants. They are based on anthocyanidins or 3-deoxyanthocyanidins having in common a C15-skeleton and are unique in terms of how each anthocyanidin is involved in a network of equilibria between different forms exhibiting their own properties including colour. Sphagnorubin C (1) isolated from the cell wall of peat moss (Sphagnum sp.) was in fairly acidic and neutral dimethyl sulfoxide characterized by nuclear magnetic resonance (NMR) and ultraviolet–visible (UV–vis) absorption techniques. At equilibrium, the network of 1 behaved as a two–component colour system involving the reddish flavylium cationic and the yellow trans–chalcone forms. The additional D- and E-rings connected to the common C15-skeleton extend the π-conjugation within the molecule and provide both bathochromic shifts in the absorption spectra of the various forms as well as a low isomerization barrier between the cis- and trans-chalcone forms. The hemiketal and cis-chalcone forms were thus not observed experimentally by NMR due to their short lives. The stable, reversible network of 1 with good colour contrast between its two components has previously not been reported for other natural anthocyanins and might thus have potential in future photochromic systems. This is the first full structural characterization of any naturally occurring anthocyanin chalcone form.

scholarly journals Characterization of moisture in acetylated and propionylated radiata pine using low-field nuclear magnetic resonance (LFNMR) relaxometry

Holzforschung ◽  
2018 ◽  
Vol 72 (3) ◽  
pp. 225-233 ◽  
Author(s):  
Greeley Beck ◽  
Emil Engelund Thybring ◽  
Lisbeth Garbrecht Thygesen ◽  
Callum Hill
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Cell Wall ◽  
Magnetic Resonance ◽  
Relaxation Times ◽  
Radiata Pine ◽  
Saturation Point ◽  
Weight Percentage ◽  
Low Field ◽  
Nuclear Magnetic

AbstractMoisture in radiata pine (Pinus radiataD. Don) earlywood (EW), which was acetylated or propionylated to various degrees, was measured by low-field nuclear magnetic resonance (LFNMR) relaxometry. Spin-spin relaxation times (T2) were determined for fully saturated samples at 22 and −18°C.T2values for EW lumen water increased with increasing acetylation weight percentage gain (WPG), perhaps caused by the less hydrophilic acetylated wood (AcW) surface. Cell wall water (WCW) and the water in pits and small voids also showed increasingT2values as a function of WPG but with a weaker tendency. A possible explanation is the counteracting effects of decreased hydrophilicity and reduced moisture content (MC) of these water populations at higher levels of acetylation. The evaluation of propionylation on WCWT2data was complicated by peak splitting in the relaxation spectrum. ConstantT2values for void water populations at various WPG levels for propionylated samples indicate a modification gradient in the cell wall. Fiber saturation point (FSP) was significantly reduced by both modifications. Slightly higher FSP values for propionylated samples suggest that physical bulking is not the only factor causing moisture exclusion in AcW. But this interpretation is tentative because of the possibility of cell wall damage caused by propionylation.

Isolation and Characterization of the Photoalteration Products of cis- and trans-Chlordane

1975 ◽  
Vol 58 (1) ◽  
pp. 6-9
Author(s):  
Francis I Onuska ◽  
Michael E Comba
Keyword(s):  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Thin Layer ◽  
High Yield ◽  
Isolation And Characterization ◽  
The Individual ◽  
Cis And Trans ◽  
Layer Chromatography

Abstract Ultraviolet irradiation of cis- and trares-chlordane yielded 3 photolysis products. The expected half-caged analog of cis-chlordane was formed in high yield, and 2 minor photoproducts of trans-chlordane were observed. One of these products was a half-caged isomer. The individual photoproducts were isolated by thin layer chromatography and characterized by infrared, nuclear magnetic resonance, and mass spectrometry.

scholarly journals Characterization of a Salmonella sugar kinase essential for the utilization of fructose-asparagine

2017 ◽  
Vol 95 (2) ◽  
pp. 304-309 ◽  
Author(s):  
Pradip K. Biswas ◽  
Edward J. Behrman ◽  
Venkat Gopalan
Keyword(s):  
Amino Acid ◽  
Mouse Models ◽  
Biochemical Characterization ◽  
Intestinal Inflammation ◽  
Sequential Action ◽  
Carbon And Nitrogen ◽  
Naturally Occurring ◽  
The Common ◽  
Sugar Kinase

Salmonella can utilize fructose-asparagine (F-Asn), a naturally occurring Amadori product, as its sole carbon and nitrogen source. Conversion of F-Asn to the common intermediates glucose-6-phosphate, aspartate, and ammonia was predicted to involve the sequential action of an asparaginase, a kinase, and a deglycase. Mutants lacking the deglycase are highly attenuated in mouse models of intestinal inflammation owing to the toxic build-up of the deglycase substrate. The limited distribution of this metabolic pathway in the animal gut microbiome raises the prospects for antibacterial discovery. We report the biochemical characterization of the kinase that was expected to transform fructose-aspartate to 6-phosphofructose-aspartate during F-Asn utilization. In addition to confirming its anticipated function, we determined through studies of fructose-aspartate analogues that this kinase exhibits a substrate-specificity with greater tolerance to changes to the amino acid (including the d-isomer of aspartate) than to the sugar.

Characterization of FeOOH polymorphs and ferrihydrite using low-temperature, applied-field, Mössbauer spectroscopy

Clay Minerals ◽  
1992 ◽  
Vol 27 (1) ◽  
pp. 57-71 ◽  
Author(s):  
R. J. Pollard ◽  
C. M. Cardile ◽  
D. G. Lewis ◽  
L. J. Brown
Keyword(s):  
Mössbauer Spectroscopy ◽  
Quantitative Analysis ◽  
Low Temperatures ◽  
Applied Field ◽  
Mossbauer Spectroscopy ◽  
Magnetic Structures ◽  
Mößbauer Spectroscopy ◽  
Naturally Occurring ◽  
The Common

AbstractMössbauer spectroscopy obtained with the sample at low temperatures and subject to large magnetic fields is discussed in terms of its use in analysing the naturally occurring polymorphs of FeOOH and the common growth precursor, ferrihydrite. Experiments on well-characterized synthetic samples provided benchmark results. A relatively simple means of quantitative analysis was used, in which sextets of Voigtian-shaped lines were summed and least-squares fitted. The results are discussed in terms of the magnetic structures of each compound.

High Resolution Replication of Organoclay Surfaces

1982 ◽  
Vol 40 ◽  
pp. 576-577
Author(s):  
W. W. Barker ◽  
W. E. Rigsby ◽  
V. J. Hurst ◽  
W. J. Humphreys
Keyword(s):  
Clay Mineral ◽  
Organic Molecule ◽  
Organic Molecules ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Naturally Occurring ◽  
Silicate Layers ◽  
Mineral Identification

Experimental clay mineral-organic molecule complexes long have been known and some of them have been extensively studied by X-ray diffraction methods. The organic molecules are adsorbed onto the surfaces of the clay minerals, or intercalated between the silicate layers. Natural organo-clays also are widely recognized but generally have not been well characterized. Widely used techniques for clay mineral identification involve treatment of the sample with H2 O2 or other oxidant to destroy any associated organics. This generally simplifies and intensifies the XRD pattern of the clay residue, but helps little with the characterization of the original organoclay. Adequate techniques for the direct observation of synthetic and naturally occurring organoclays are yet to be developed.

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