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The feasibility of degrading triphenylmethane dyes by Trametes versicolor and laccase has been investigated for the following dyes: Acid Fuchsin, Brilliant Green 1, Basic Fuchsin, Methyl Green or Acid Green 16. The toxicity level of triphenylmethane dyes is linked to their basic character, but significant detoxification is obtained when there is biodegradation. Identification of enzymatic degradation products by 1H NMR made it possible to propose a general rule for the laccase attack on triphenylmethane compounds. The enzyme completely degrades the molecular part of the canonical resonance substructures of dyes, because no N-substituted, mono-N and di-N,N substituted p-amine aromatic residues seem to be wholly degraded. No enzymatic degradation is observed in the cases of either the non-substituted or trisubstituted-N,N,N p-amine aromatic residues. On the other hand, for all the dyes tested, no aromatic residues are detected after fungal treatment; this means that T. versicolor is more capable of performing further degradation than is laccase. The results of this study demonstrated that compounds with a triphenylmethane structure can be degraded by T. versicolor even if they are highly toxic. The enzyme laccase plays an important role in the attack on the structure and a general rule for predicting which products would be obtained after the enzymatic treatment is suggested. [Copyright &y& Elsevier]

Abstract: For the first time, a simple NMR methodology is proposed for the accurate determination of the effect of the substitution of 12C by 13C on the chemical shifts of protons separated by two-bonds in small molecules in their natural abundance. [Copyright &y& Elsevier]

The white-rot fungus Trametes versicolor degraded trichloroethylene (TCE), a highly oxidized chloroethene, and produced 2,2,2-trichloroethanol and carbon dioxide as the main products of degradation, based on the results obtained using [13C]-TCE as the substrate. For a range of concentrations of TCE between 2 and 20mgl−1, 53% of the theoretical maximum chloride expected from complete degradation of TCE was observed. Laccase was shown to be induced by TCE, but did not appear to play a role in TCE degradation. Cytochrome P-450 appears to be involved in TCE degradation, as evidenced by marked inhibition of degradation of TCE in the presence of 1-aminobenzotriazole, a known inhibitor of cytochrome P-450. Our results suggested that chloral (trichloroacetaldehyde) was an intermediate of the TCE degradation pathway. The results indicate that the TCE degradation pathway in T. versicolor appears to be similar to that previously reported in mammals and is mechanistically quite different from bacterial TCE degradation. [Copyright &y& Elsevier]

Serum 1H NMR metabolomics has been used as a diagnostic tool for screening type 2 diabetes (T2D) with chronic kidney disease (CKD) as comorbidity. This work aimed to evaluate 1H NMR data to detect the initial kidney damage and CKD in T2D subjects, through multivariate statistical analysis. Clinical data and biochemical parameters were obtained for classifying five experimental groups using KDIGO guidelines: Control (healthy subjects), T2D, T2D-CKD-mild, T2D-CKD-moderate, and T2D-CKD-severe. Serum 1H NMR spectra were recorded to follow two strategies: one based on metabolite-to-creatinine (Met/Cr) ratios as targeted metabolomics, and the second one based on untargeted metabolomics from the 1H NMR profile. A prospective biomarkers panel of the early stage of T2D-CKD based in metabolite-to-creatinine ratio (ornithine/Cr, serine/Cr, mannose/Cr, acetate/Cr, acetoacetate/Cr, formate/Cr, and glutamate/Cr) was proposed. Later, a statistical model based on non-targeted metabolomics was used to predict initial CKD, and its metabolic pathway analysis allowed identifying the most affected pathways: phenylalanine, tyrosine, and tryptophan biosynthesis; valine, leucine, and isoleucine degradation; glyoxylate and dicarboxylate metabolism; glycine, serine, and threonine metabolism; and histidine metabolism. Nonetheless, further studies with a larger cohort are advised to precise ranges in metabolite-to-creatinine ratios and evaluate the prediction pertinency to detect initial CKD in T2D patients in both statistical models proposed. [Display omitted] • Serum 1H NMR metabolomics signature to identify initial kidney damage of T2D. • Targeted PLS-DA revealed seven metabolite-to-creatinine ratios as early biomarkers. • A T2D-CKD model based on non-targeted metabolomics to predict the early stage. • Differential metabolites depicted the metabolic pathway imbalance of T2D-CKD. [ABSTRACT FROM AUTHOR]

Abstract: This work examines the influence of N-protecting groups on the conversion and stereoselectivity of dihydroxyacetone phosphate (DHAP) dependent aldolase-catalyzed aldol additions of DHAP to N-protected-3-aminopropanal. Phenylacetyl-(PhAc-), tert-butyloxycarbonyl- ( t Boc-) and fluoren-9-ylmethoxycarbonyl- (Fmoc-)-3-aminopropanal were evaluated as substrates for d-fructose 1,6-bisphosphate aldolase from rabbit muscle (RAMA), and l-rhamnulose-1-phosphate aldolase (RhuA) and l-fuculose-1-phosphate aldolase (FucA), both from Escherichia coli. Using PhAc and t Boc ca. 70% conversions to the aldol adduct were achieved, whereas Fmoc gave maximum conversions of ca. 25%. The stereoselectivity of the DHAP-aldolases did not depend on the N-protected-3-aminopropanal derivative. Moreover, inversion of FucA stereoselectivity relative to that obtained with the natural l-lactaldehyde was observed. Both N-PhAc and t Boc adduct product derivatives were successfully deprotected by penicillin G acylase (PGA)-catalyzed hydrolysis at pH 7 and by treatment with aqueous TFA (6% v/v), respectively. However, the corresponding cyclic imine sugars could not be isolated, presumable due to the presence of a highly reactive primary amine and a keto group in the molecule, which lead to a number of unexpected reactions. [Copyright &y& Elsevier]

Type 2 diabetes mellitus (DM2) is a multimorbidity, long-term condition, and one of the worldwide leading causes of chronic kidney disease (CKD) –a silent disease, usually detected when non-reversible renal damage have already occurred. New strategies and more effective laboratory methods are needed for more opportune diagnosis of DM2-CKD. This study comprises clinical parameters and nuclear magnetic resonance (NMR)-based urine metabolomics data from 60 individuals (20–65 years old, 67.7% females), sorted in 5 experimental groups (healthy subjects; diabetic patients without any clinical sign of CKD; and patients with mild, moderate, and severe DM2-CKD), according to KDIGO. DM2-CKD produces a continuous variation of the urine metabolome, characterized by an increase/decrement of a group of metabolites that can be used to monitor CKD progression (trigonelline, hippurate, phenylalanine, glycolate, dimethylamine, alanine, 2-hydroxybutyrate, lactate, and citrate). NMR profiles were used to obtain a statistical model, based on partial least squares analysis (PLS-DA) to discriminate among groups. The PLS-DA model yielded good validation parameters (sensitivity, specificity, and area under the curve (AUC) of the receiver operating characteristic curve (ROC) plot: 0.692, 0.778 and 0.912, respectively) and, thus, it can differentiate between subjects with DM2-CKD in early stages, from subjects with a mild or severe condition. This metabolic signature exhibits a molecular variation associated to DM2-CKD, and data suggests it can be used to predict risk of DM2-CKD in patients without clinical signs of renal disease, offering a new alternative to current diagnosis methods. [Display omitted] • Diabetic renal disease produced a continuous variation of the urine metabolome. • PLS-DA model discriminate between disease groups using NMR profiles. • Nine metabolites were proposed as potential progression biomarkers. • This method offers a new alternative to current diagnosis procedures. [ABSTRACT FROM AUTHOR]

Abstract: The novel tetradentate ligand 1,4-bis(4-(4′-methyl)-2,2′-bipyridyl)-2,3-diaza-1,3-butadiene (BBDB) was synthesized and characterized by spectroscopic techniques. New complexes of Re and Ru of formulae: [Re(BBDB)(CO)3(Cl)], [(CH3CN)(CO)3Re(μ-BBDB)Re–(CO)3(CH3CN)]2+, [(bpy)2Ru-(μ-BBDB)Ru(bpy)2]4+, [(NH3)4Ru(μ-BBDB)–Ru(NH3)4]4+ (bpy=2,2′-bipyridine) and complexes of Ru with 4-Me-4′-CO2H-bpy (=4-methyl-4′-carboxylic acid-2,2′-bipyridine) – the hydrolyzed derivative of BBDB – of formulae: [(Ru(4-Me-4′-CO2H-bpy)(bpy)2]2+ and [Ru(4-Me-4′-CO2H-bpy)(CN)4]2− were prepared and characterized by spectroscopic, electrochemical and computational techniques. The disclosed enhanced electronic coupling in the mixed-valent complex with ruthenium ammines can be explained by the electronic delocalization imposed by the C N N C backbone. DFT and TD-DFT calculations can predict the optical properties and electronic structures of the reported complexes and comparisons with calculations performed on previously reported complexes with 4-pyridinaldazine can account for their photophysical behaviour. [Copyright &y& Elsevier]

Abstract: High pressure processing (HPP) has become a popular method to reduce bacterial load on dry-cured ham. However, HPP processed hams tend to present higher saltiness than non-processed ones. In this study was evaluated the effect of processing biceps femoris samples of 9 dry-cured hams aged for 15months at a pressure of 0.1, 300, 600 and 900MPa. 23Na-Nuclear Magnetic Resonance (NMR) relaxation values were used to determine the mobility of sodium. Ultrastructure changes at 600MPa were evaluated by transmission electron microscopy (TEM) analysis. Double quantum NMR experiments demonstrated that pressure promoted tighter binding of bound sodium to proteins. However, a small proportion of sodium was liberated. The modification of myofibril ultrastructure at 600MPa observed by TEM and the denaturation observed between 300 and 600MPa facilitate the liberation of a proportion of sodium. That together with the decrease of water holding capacity between unpressurised and 900MPa samples makes sodium more noticeable for saltiness perception, which could be of interest for sodium reduced dry-cured meat products. Industrial relevance: High pressure processing of cured ham is a non-thermal pasteurization actually used in Spain. Even if the technology answer the microbiological goals to control microorganisms, an increase of saltiness perception have been detected. The understanding of this phenomenon from an ultrastructural and molecular perspective could help to present high pressure processing treatments as an alternative solution for salt reduction in dry-cured meat products in order to obtain healthier food products and good consumer acceptance. [Copyright &y& Elsevier]

Abstract: The synthesis of some representative compounds of a new class of cyclobutane-containing β-peptides starting from (−)-verbenone as a chiral precursor is presented. In these products, the cyclobutane moiety is not a part of the peptide backbone but a bulky substituent at the β3-position. These compounds have been carefully characterized and studied on the basis of the combined use of several experimental techniques together with molecular modeling by means of theoretical calculations. In the solid state, the non-cyclic β-peptides adopt a hairpin-like molecular folding ruled by intermolecular hydrogen bonds in the crystal packing. [Copyright &y& Elsevier]

Abstract: New coordination compounds of formulae: [Ru(trpy)(bpy)(4,4′-azpy)]2+, 1, [Ru(tpm)(bpy)(4,4′-azpy)]2+, 2, [(trpy)(bpy)Ru(4,4′-azpy)Ru(NH3)5]4+, 3, and [(trpy)(bpy)Ru(4,4′-azpy)Ru(bpy)(trpy)]4+, 5, with trpy=2,2′:6′,2″-terpyridine, tpm=tris(1-pyrazolyl)methane), bpy=2,2′-bipyridine and 4,4′-azpy=4,4′-azobis(pyridine), have been synthesized as salts and characterized by spectroscopic and electrochemical techniques. The structure of the cation [Ru(trpy)(bpy)(4,4′-azpy)]2+ has been determined by X-ray diffraction analysis, which reveals a trans-configuration of coordinated 4,4′-azpy and a packing structure that is based on extensive π-interactions within neighboring molecules. Upon controlled potential electrolysis of the dinuclear [RuII,RuII] complex 3, a stable [RuII, RuIII] mixed-valent species, 4, was detected. From spectral data and Gaussian deconvolution analysis of the intervalence transition in 4, a strong electronic interaction between both ruthenium centers is disclosed (H AB =550cm−1), pointing to possible applications of 4,4′-azpy as a conducting bridge in “molecular wires”. [Copyright &y& Elsevier]

Abstract: The preparation and characterization by spectroscopic and electrochemical techniques of new dinuclear complexes of the type [(tpm)(bpy)RuII(L)RuII/III(NH3)5]4+/5+ (bpy=2,2′-bipyridine), tpm=tris(1-pyrazolyl)methane, L=pz (pyrazine), 4,4′-bpy (4,4′-bipyridine), BPE (trans-1,2-bis(4-pyridyl)ethylene) and PCA (=4-pyridinecarboxaldehyde azine), are described in this work. The analysis of the visible spectral data for the metal-to-metal charge transfer (MMCT) bands in the corresponding mixed-valent species (Rub =Ru bonded to bpy; Rua =Ru bonded to NH3) allows the determination of the reorganization energies λ and electronic coupling elements H AB for the intramolecular electron transfers mediated by L. An increased transmission of the metal-to-metal electronic interaction is disclosed for this series, when comparing the distance dependence of H AB to that of the analogous series with trpy (2,2′:6′,2″-terpyridine) acting as a spectator ligand instead of tpm. [Copyright &y& Elsevier]

Abstract: The bioassay-guided fractionation of the antifungal dichloromethane extract from the roots of Vernonanthura tweedieana (Baker) H. Rob. (Asteraceae), using an agar overlay bioautographic method, allowed the isolation of one active sesquiterpene (1), identified as 6-cinnamoyloxy-1-hydroxyeudesm-4-en-3-one. Minimal inhibitory concentrations (MIC) and minimal fungicidal concentrations (MFC) of 1 showed Trichophyton mentagrophytes as the most sensitive strain, with the same MIC and MFC values (4μg/ml). [Copyright &y& Elsevier]

A highly stereoselective and efficient synthetic approach to cyclobutane and cyclobutene derivatives has been developed consisting of a [2+2] photochemical cycloaddition of chiral 2(5H)-furanones to (Z)-1,2-dichloroethylene followed by dihydrodehalogenation or dihaloelimination. [Copyright &y& Elsevier]

This is the first report of applications of spectral changes originated from a double proton-coupled electron transfer of an azo group in a bipyridyl ligand coordinated to tetracyanoruthenium(II) for molecular sensing purposes, in particular for detecting the biologically relevant analyte l -Cysteine. A novel tetracyanoruthenium(II) complex of formula K 2 [Ru(4,4″-azobpy)(CN) 4 ], (1), with 4,4″-azobpy = 4,4″-azobis-(2,2′-bipyridine), has been synthesized and characterized by spectroscopic, electrochemical and photophysical techniques. The effects of reduction and protonation of the azo group of coordinated 4,4″-azobpy in the UV–Vis absorption and emission spectra of (1) were explored by spectroelectrochemical techniques and by addition of l -Cysteine. The behavior of (1) as a "molecular switch" could be explained with the aid of quantum–mechanical calculations by using density functional theory. [ABSTRACT FROM AUTHOR]