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1.
Molecules ; 27(20)2022 Oct 21.
Artículo en Inglés | MEDLINE | ID: mdl-36296711

RESUMEN

In this study, superparamagnetic iron oxide nanoparticles (SPIONs) were engineered with an organic coating composed of low molecular weight heparin (LMWH) and bovine serum albumin (BSA), providing heparin-based nanoparticle systems (LMWH@SPIONs). The purpose was to merge the properties of the heparin skeleton and an inorganic core to build up a targeted theranostic nanosystem, which was eventually enhanced by loading a chemotherapeutic agent. Iron oxide cores were prepared via the co-precipitation of iron salts in an alkaline environment and oleic acid (OA) capping. Dopamine (DA) was covalently linked to BSA and LMWH by amide linkages via carbodiimide coupling. The following ligand exchange reaction between the DA-BSA/DA-LMWH and OA was conducted in a biphasic system composed of water and hexane, affording LMWH@SPIONs stabilized in water by polystyrene sulfonate (PSS). Their size and morphology were investigated via dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. The LMWH@SPIONs' cytotoxicity was tested, showing marginal or no toxicity for samples prepared with PSS at concentrations of 50 µg/mL. Their inhibitory activity on the heparanase enzyme was measured, showing an effective inhibition at concentrations comparable to G4000 (N-desulfo-N-acetyl heparin, a non-anticoagulant and antiheparanase heparin derivative; Roneparstat). The LMWH@SPION encapsulation of paclitaxel (PTX) enhanced the antitumor effect of this chemotherapeutic on breast cancer cells, likely due to an improved internalization of the nanoformulated drug with respect to the free molecule. Lastly, time-domain NMR (TD-NMR) experiments were conducted on LMWH@SPIONs obtaining relaxivity values within the same order of magnitude as currently used commercial contrast agents.


Asunto(s)
Nanopartículas de Magnetita , Nanopartículas , Nanopartículas de Magnetita/química , Albúmina Sérica Bovina , Hexanos , Medios de Contraste , Ácido Oléico , Medicina de Precisión , Ligandos , Heparina de Bajo-Peso-Molecular/farmacología , Dopamina , Sales (Química) , Compuestos Férricos/química , Nanopartículas/química , Heparina , Nanopartículas Magnéticas de Óxido de Hierro , Paclitaxel , Hierro , Agua , Carbodiimidas , Amidas
2.
Molecules ; 26(15)2021 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-34361726

RESUMEN

FINEAU (2021-2024) is a trans-disciplinary research project involving French, Serbian, Italian, Portuguese and Romanian colleagues, a French agricultural cooperative and two surface-treatment industries, intending to propose chènevotte, a co-product of the hemp industry, as an adsorbent for the removal of pollutants from polycontaminated wastewater. The first objective of FINEAU was to prepare and characterize chènevotte-based materials. In this study, the impact of water washing and treatments (KOH, Na2CO3 and H3PO4) on the composition and structure of chènevotte (also called hemp shives) was evaluated using chemical analysis, X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, X-ray computed nanotomography (nano-CT), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, solid state NMR spectroscopy and thermogravimetric analysis. The results showed that all these techniques are complementary and useful to characterize the structure and morphology of the samples. Before any chemical treatment, the presence of impurities with a compact unfibrillated structure on the surfaces of chènevotte samples was found. Data indicated an increase in the crystallinity index and significant changes in the chemical composition of each sample after treatment as well as in surface morphology and roughness. The most significant changes were observed in alkaline-treated samples, especially those treated with KOH.


Asunto(s)
Cannabis/química , Productos Agrícolas/química , Residuos/análisis , Aguas Residuales/química , Contaminantes Químicos del Agua/aislamiento & purificación , Adsorción , Europa (Continente) , Humanos , Cinética , Ensayo de Materiales , Termogravimetría
3.
Molecules ; 23(12)2018 Dec 11.
Artículo en Inglés | MEDLINE | ID: mdl-30544937

RESUMEN

Multiple osteochondromas (MO) is a hereditary disorder associated with benign cartilaginous tumors, known to be characterized by absence or highly reduced amount of heparan sulfate (HS) in the extracellular matrix of growth plate cartilage, which alters proper signaling networks leading to improper bone growth. Although recent studies demonstrated accumulation of HS in the cytoplasm of MO chondrocytes, nothing is known on the structural alterations which prevent HS from undergoing its physiologic pathway. In this work, osteochondroma (OC), peripheral chondrosarcoma, and healthy cartilaginous human samples were processed following a procedure previously set up to structurally characterize and compare HS from pathologic and physiologic conditions, and to examine the phenotypic differences that arise in the presence of either exostosin 1 or 2 (EXT1 or EXT2) mutations. Our data suggest that HS chains from OCs are prevalently below 10 kDa and slightly more sulfated than healthy ones, whereas HS chains from peripheral chondrosarcomas (PCSs) are mostly higher than 10 kDa and remarkably more sulfated than all the other samples. Although deeper investigation is still necessary, the approach here applied pointed out, for the first time, structural differences among OC, PCS, and healthy HS chains extracted from human cartilaginous excisions, and could help in understanding how the structural features of HS are modulated in the presence of pathological situations also involving different tissues.


Asunto(s)
Neoplasias Óseas/química , Cartílago/patología , Condrosarcoma/química , Heparitina Sulfato/química , Osteocondroma/química , Adolescente , Adulto , Neoplasias Óseas/patología , Cartílago/química , Cartílago/embriología , Niño , Preescolar , Condrosarcoma/patología , Cromatografía Líquida de Alta Presión , Femenino , Heparitina Sulfato/análisis , Humanos , Imagen por Resonancia Magnética , Espectrometría de Masas/métodos , Mutación , N-Acetilglucosaminiltransferasas/genética , Osteocondroma/patología
4.
Beilstein J Org Chem ; 12: 1826-1838, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27829889

RESUMEN

In this study, a polymer, prepared by crosslinking cyclodextrin (CD) by means of a polycarboxylic acid, was used for the removal of pollutants from spiked solutions and discharge waters from the surface treatment industry. In spiked solutions containing five metals, sixteen polycyclic aromatic hydrocarbons (PAH) and three alkylphenols (AP), the material exhibited high adsorption capacities: >99% of Co2+, Ni2+ and Zn2+ were removed, between 65 and 82% of the PAHs, as well as 69 to 90% of the APs. Due to the structure of the polymer and its specific characteristics, such as the presence of carboxylic groups and CD cavities, the adsorption mechanism involves four main interactions: ion exchange, electrostatic interactions and precipitation for metal removal, and inclusion complexes for organics removal. In industrial discharge waters, competition effects appeared, especially because of the presence of calcium at high concentrations, which competed with other pollutants for the adsorption sites of the adsorbent.

5.
Anal Chem ; 87(13): 6709-17, 2015 Jul 07.
Artículo en Inglés | MEDLINE | ID: mdl-26020452

RESUMEN

An interlaboratory comparison (ILC) was organized with the aim to set up quality control indicators suitable for multicomponent quantitative analysis by nuclear magnetic resonance (NMR) spectroscopy. A total of 36 NMR data sets (corresponding to 1260 NMR spectra) were produced by 30 participants using 34 NMR spectrometers. The calibration line method was chosen for the quantification of a five-component model mixture. Results show that quantitative NMR is a robust quantification tool and that 26 out of 36 data sets resulted in statistically equivalent calibration lines for all considered NMR signals. The performance of each laboratory was assessed by means of a new performance index (named Qp-score) which is related to the difference between the experimental and the consensus values of the slope of the calibration lines. Laboratories endowed with a Qp-score falling within the suitable acceptability range are qualified to produce NMR spectra that can be considered statistically equivalent in terms of relative intensities of the signals. In addition, the specific response of nuclei to the experimental excitation/relaxation conditions was addressed by means of the parameter named NR. NR is related to the difference between the theoretical and the consensus slopes of the calibration lines and is specific for each signal produced by a well-defined set of acquisition parameters.

6.
Biochem Biophys Res Commun ; 425(4): 794-9, 2012 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-22884801

RESUMEN

The naturally occurring anionic cell surface polysaccharide heparan sulfate is involved in key biological activities and is implicated in amyloid formation. Following addition of Zn-heparan sulfate, hen lysozyme, a model amyloid forming protein, resembled ß-rich amyloid by far UV circular dichroism (increased ß-sheet: +25%), with a significantly reduced melting temperature (from 68 to 58 °C) by fluorescence shift assay. Secondary structure stability of the Zn-heparan sulfate complex with lysozyme was also distinct from that with heparan sulfate, under stronger denaturation conditions using synchrotron radiation circular dichroism. Changing the cation associated with heparan sulfate is sufficient to alter the conformation and stability of complexes formed between heparan sulfate and lysozyme, substantially reducing the stability of the protein. Complexes of heparan sulfate and cations, such as Zn, which are abundant in the brain, may provide alternative folding routes for proteins.


Asunto(s)
Heparitina Sulfato/química , Muramidasa/química , Zinc/química , Animales , Dicroismo Circular , Estabilidad de Enzimas , Pliegue de Proteína , Estructura Secundaria de Proteína
7.
Environ Sci Pollut Res Int ; 29(1): 171-181, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34014475

RESUMEN

Alkylphenols are industrial pollutants commonly present in wastewater. They are difficult to eliminate by conventional treatment processes, ending up in the sludge of wastewater treatment plants. In this study, we propose to use cross-linked cyclodextrin-based polymers (ECP) as sorbents to treat three alkylphenols, namely, one nonylphenol (4-n-NP) and two octylphenols (4-n-OP and 4-tert-OP), present in aqueous solution by a batch method. The experiments were carried out with five cyclodextrin polymers (α-ECP, ß-ECP, γ-ECP, α,ß,γ-ECP, and HP-ß-ECP). Sorption results showed that all polymers, with the exception of α-ECP, had high sorption capacities between 60 and 100% of the alkylphenols in the concentration range studied (between 25 and 100 µg/L). In all cases, HP-ß-ECP has shown the highest removals, regardless of the structure of the molecule. The order obtained was HP-ß-ECP >> ß-ECP ~ α,ß,γ-ECP >> γ-ECP > α-ECP. The 4-tert-OP compound was the best adsorbed, regardless the material and the solution studied. Sorption results also indicated that (i) the sorption efficiency decreased with the increasing of alkylphenol concentration; (ii) sodium chloride had a strong negative effect on the sorption process; and (iii) the performance remained unchanged after five sorption-regeneration cycles. The main sorption mechanism of alkylphenols occurring in ECP was the inclusion within the cyclodextrin cavities. The obtained results proved that cyclodextrin polymers could serve as efficient sorbents for the removal of alkylphenols from real effluents.


Asunto(s)
Ciclodextrinas , Contaminantes Químicos del Agua , Fenoles , Polímeros , Contaminantes Químicos del Agua/análisis
8.
Front Bioeng Biotechnol ; 10: 833157, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35155396

RESUMEN

The dissolution of Bombyx mori silk fibroin (SF) films in formic acid (FA) for the preparation of electrospinning dopes is widely exploited to produce electrospun SF scaffolds. The SILKBridge® nerve conduit is an example of medical device having in its wall structure an electrospun component produced from an FA spinning dope. Though highly volatile, residual FA remains trapped into the bulk of the SF nanofibers. The purpose of this work is to investigate the type and strength of the interaction between FA and SF in electrospun mats, to quantify its amount and to evaluate its possible toxicological impact on human health. The presence of residual FA in SF mats was detected by FTIR and Raman spectroscopy (new carbonyl peak at about 1,725 cm-1) and by solid state NMR, which revealed a new carbonyl signal at about 164.3 ppm, attributed to FA by isotopic 13C substitution. Changes occurred also in the spectral ranges of hydroxylated amino acids (Ser and Thr), demonstrating that FA interacted with SF by forming formyl esters. The total amount of FA was determined by HS-GC/MS analysis and accounted for 247 ± 20 µmol/g. The greatest part was present as formyl ester, a small part (about 3%) as free FA. Approximately 17% of the 1,500 µmol/g of hydroxy amino acids (Ser and Thr) theoretically available were involved in the formation of formyl esters. Treatment with alkali (Na2CO3) succeeded to remove the greatest part of FA, but not all. Alkali-treated electrospun SF mats underwent morphological, physical, and mechanical changes. The average diameter of the fibers increased from about 440 nm to about 480 nm, the mat shrunk, became stiffer (the modulus increased from about 5.5 MPa to about 7 MPa), and lost elasticity (the strain decreased from about 1 mm/mm to about 0.8 mm/mm). Biocompatibility studies with human adult dermal fibroblasts did not show significant difference in cell proliferation (313 ± 18 and 309 ± 23 cells/mm2 for untreated and alkali-treated SF mat, respectively) and metabolic activity. An in-depth evaluation of the possible toxicological impact of residual FA was made using the SILKBridge® nerve conduit as case study, following the provisions of the ISO 10993-1 standard. The Potential Patient Daily Intake, calculated from the total amount of FA determined by HS-GC/MS, was 2.4 mg/day and the Tolerable Exposure level was set to 35.4 mg/day. This allowed to obtain a value of the Margin of Safety of 15, indicating that the amount of FA left on SF mats after electrospinning does not raise concerns for human health.

9.
Analyst ; 136(11): 2330-8, 2011 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-21494716

RESUMEN

Recently, oversulfated chondroitin sulfate (OSCS) was identified in contaminated heparin preparations, which were linked to several adverse clinical events and deaths. Orthogonal analytical techniques, namely nuclear magnetic resonance (NMR) and capillary electrophoresis (CE), have since been applied by several authors for the evaluation of heparin purity and safety. NMR identification and quantification of residual solvents and non-volatile low molecular contaminants with USP acceptance levels of toxicity was achieved 40-fold faster than the traditional GC-headspace technique, which takes ~120 min against ~3 min to obtain a (1)H NMR spectrum with a signal/noise ratio of at least 1000/1. The procedure allowed detection of Class 1 residual solvents at 2 ppm and quantification was possible above 10 ppm. 2D NMR techniques (edited-HSQC (1)H/(13)C) permitted visualization of otherwise masked EDTA signals at 3.68/59.7 ppm and 3.34/53.5 ppm, which may be overlapping mononuclear heparin signals, or those of ethanol and methanol. Detailed NMR and ESI-MS/MS studies revealed a hitherto unknown contaminant, tris(2-n-butoxyethyl) phosphate (TBEP), which has potential health risks.


Asunto(s)
Heparina/química , Espectroscopía de Resonancia Magnética/métodos , Organofosfatos/análisis , Electroforesis Capilar/métodos , Solventes/química
10.
Biomolecules ; 11(3)2021 03 05.
Artículo en Inglés | MEDLINE | ID: mdl-33808040

RESUMEN

Non-covalent interactions in supramolecular chemistry provide useful systems to understand biological processes, and self-assembly systems are suitable assets to build-up innovative products for biomedical applications. In this field, polyelectrolyte complexes are interesting, especially when polysaccharides are involved, due to their non-toxicity and bio-absorbability. In this work, we investigated a polyelectrolyte formed by hyaluronic acid (HA), a negatively charged linear polysaccharide, with Chitlac (Ch), a positively charged lactose-modified chitosan. The aim of the study was the investigation of a novel Ch-HA polyelectrolyte complex, to understand the interaction between the two polysaccharides and the stability towards enzymatic activity. By means of gel permeation chromatography-triple detector array (GPC-TDA), nuclear magnetic resonance (NMR), dynamic viscosity, Zeta Potential and scanning electron microscopy (SEM), the polyelectrolyte complex properties were identified and compared to individual polysaccharides. The complex showed monodisperse molecular weight distribution, high viscosity, negative charge, and could be degraded by specific enzymes, such as hyaluronidase and lysozyme. The results suggest a close interaction between the two polysaccharides in the complex, which could be considered a self-assembly system.


Asunto(s)
Biopolímeros/química , Quitosano/química , Ácido Hialurónico/química , Lactosa/química , Animales , Humanos , Hialuronoglucosaminidasa/química , Hialuronoglucosaminidasa/metabolismo , Espectroscopía de Resonancia Magnética , Microscopía Electrónica de Rastreo , Reología
11.
Nanomaterials (Basel) ; 11(2)2021 Feb 13.
Artículo en Inglés | MEDLINE | ID: mdl-33668489

RESUMEN

Nanocellulose (NC) is getting ahead as a renewable, biodegradable and biocompatible biomaterial. The NCs for this study were recovered from industrial cotton waste (CFT) by acid hydrolysis (HNC) and by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) mediated oxidation (ONC). They were functionalized by radical based glycidyl methacrylate (GMA) grafting providing crystalline HNC-GMA and ONC-GMA, and by allylation (ALL) providing amorphous HNC-ALL and ONC-ALL. HNC, ONC and their derivatives were chemically and morphologically characterized. Crystalline NCs were found capable to adsorb, from diluted water solution (2 × 10-3 M), the antibiotics vancomycin (VC), ciprofloxacin (CP), amoxicillin (AM) and the disinfectant chlorhexidine (CHX), while amorphous NCs did not show any significant adsorption properties. Adsorption capability was quantified by measuring the concentration change in function of the contact time. The adsorption kinetics follow the pseudo-second order model and show complex adsorption mechanisms investigated by an intraparticle diffusion model and interpreted by structure-property relationships. ONC and ONC-GMA loaded with VC, and HNC and HNC-GMA loaded with CP were not colonized by Staphylococcus aureus and by Klebsiella pneumonia and suggested long lasting release capability. Our results can envisage developing CFT derived NCs for environmental applications (water remediation) and for biomedical applications (antibacterial NC). Among the future developments, it could also be of interest to take advantage of acidic, glycidyl and allyl groups' reactivity to provide other NCs from the NC object of this study.

12.
Biomedicines ; 9(9)2021 Sep 17.
Artículo en Inglés | MEDLINE | ID: mdl-34572438

RESUMEN

Pandemic SARS-CoV-2 causes a mild to severe respiratory disease called coronavirus disease 2019 (COVID-19). While control of the SARS-CoV-2 spread partly depends on vaccine-induced or naturally acquired protective herd immunity, antiviral strategies are still needed to manage COVID-19. Enisamium is an inhibitor of influenza A and B viruses in cell culture and clinically approved in countries of the Commonwealth of Independent States. In vitro, enisamium acts through metabolite VR17-04 and inhibits the activity of the influenza A virus RNA polymerase. Here we show that enisamium can inhibit coronavirus infections in NHBE and Caco-2 cells, and the activity of the SARS-CoV-2 RNA polymerase in vitro. Docking and molecular dynamics simulations provide insight into the mechanism of action and indicate that enisamium metabolite VR17-04 prevents GTP and UTP incorporation. Overall, these results suggest that enisamium is an inhibitor of SARS-CoV-2 RNA synthesis in vitro.

13.
medRxiv ; 2021 Jan 21.
Artículo en Inglés | MEDLINE | ID: mdl-33469600

RESUMEN

Pandemic SARS-CoV-2 causes a mild to severe respiratory disease called Coronavirus Disease 2019 (COVID-19). Control of SARS-CoV-2 spread will depend on vaccine-induced or naturally acquired protective herd immunity. Until then, antiviral strategies are needed to manage COVID-19, but approved antiviral treatments, such as remdesivir, can only be delivered intravenously. Enisamium (laboratory code FAV00A, trade name Amizon®) is an orally active inhibitor of influenza A and B viruses in cell culture and clinically approved in countries of the Commonwealth of Independent States. Here we show that enisamium can inhibit SARS-CoV-2 infections in NHBE and Caco-2 cells. In vitro, the previously identified enisamium metabolite VR17-04 directly inhibits the activity of the SARS-CoV-2 RNA polymerase. Docking and molecular dynamics simulations suggest that VR17-04 prevents GTP and UTP incorporation. To confirm enisamium's antiviral properties, we conducted a double-blind, randomized, placebo-controlled trial in adult, hospitalized COVID-19 patients, which needed medical care either with or without supplementary oxygen. Patients received either enisamium (500 mg per dose) or placebo for 7 days. A pre-planned interim analysis showed in the subgroup of patients needing supplementary oxygen (n = 77) in the enisamium group a mean recovery time of 11.1 days, compared to 13.9 days for the placebo group (log-rank test; p=0.0259). No significant difference was found for all patients (n = 373) or those only needing medical care (n = 296). These results thus suggest that enisamium is an inhibitor of SARS-CoV-2 RNA synthesis and that enisamium treatment shortens the time to recovery for COVID-19 patients needing oxygen.

14.
Front Chem ; 8: 524, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32760695

RESUMEN

The development of 3D printable hydrogels based on the crosslinking between chitosan and gelatin is proposed. Chitosan and gelatin were both functionalized with methyl furan groups. Chemical modification was performed by reductive amination with methyl furfural involving the lysine residues of gelatin and the amino groups of chitosan to generate hydrogels with tailored properties. The methyl furan residues present in both polymers were exploited for efficient crosslinking via Diels-Alder ligation with PEG-Star-maleimide under cell-compatible conditions. The obtained chitosan-gelatin hybrid was employed to formulate hydrogels and 3D printable biopolymers and its processability and biocompatibility were preliminarily investigated.

15.
Biochemistry ; 48(22): 4772-9, 2009 Jun 09.
Artículo en Inglés | MEDLINE | ID: mdl-19400583

RESUMEN

For heparan sulfate (HS) to bind and regulate the activity of proteins, the polysaccharide must present an appropriate sequence and adopt a suitable conformation. The conformations of heparin derivatives, as models of HS, are altered via a change in the associated cations, and this can drastically modify their FGF signaling activities. Here, we report that changing the cations associated with an N-acetyl-enriched heparin polysaccharide, from sodium to copper(II), converted it from supporting signaling through the fibroblast growth factor receptor (FGF-1-FGFR1c) tyrosine kinase signaling system to being inhibitory in a cell-based BaF3 assay. Nuclear magnetic resonance and synchrotron radiation circular dichroism (SRCD) spectroscopy demonstrated that the polysaccharide conformation differed in the presence of sodium or copper(II) cations. Electron paramagnetic resonance confirmed the environment of the copper(II) ion on the N-acetyl-enriched polysaccharide was distinct from that previously observed with intact heparin, which supported signaling. Secondary structures in solution complexes of polysaccharides with FGF-1 (which either supported signaling through FGFR1c or were inhibitory) were determined by SRCD. This allowed direct comparison of the two FGF-1-polysaccharide complexes in solution, containing identical molecular components and differing only in their cation content. Subtle structural differences were revealed, including a reduction in the level of disordered structure in the inhibitory complex.


Asunto(s)
Cobre/química , Factor 1 de Crecimiento de Fibroblastos/química , Factor 1 de Crecimiento de Fibroblastos/fisiología , Heparitina Sulfato/química , Receptor Tipo 1 de Factor de Crecimiento de Fibroblastos/química , Receptor Tipo 1 de Factor de Crecimiento de Fibroblastos/fisiología , Transducción de Señal/fisiología , Sodio/química , Animales , Línea Celular , Cobre/fisiología , Factor 1 de Crecimiento de Fibroblastos/antagonistas & inhibidores , Heparitina Sulfato/metabolismo , Heparitina Sulfato/fisiología , Ratones , Estructura Secundaria de Proteína , Receptor Tipo 1 de Factor de Crecimiento de Fibroblastos/antagonistas & inhibidores , Sodio/fisiología , Soluciones , Relación Estructura-Actividad
16.
Glycobiology ; 19(1): 52-67, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-18832453

RESUMEN

Principal component analysis (PCA) is a method of simplifying complex datasets to generate a lower number of parameters, while retaining the essential differences and allowing objective comparison of large numbers of datasets. Glycosaminoglycans (GAGs) are a class of linear sulfated carbohydrates with diverse sequences and consequent complex conformation and structure. Here, PCA is applied to three problems in GAG research: (i) distinguishing origins of heparin preparations, (ii) structural analysis of heparin derivatives, and (iii) classification of chondroitin sulfates (CS). The results revealed the following. (i) PCA of heparin (13)C NMR spectra allowed their origins to be distinguished and structural differences were identified. (ii) Analysis of the information-rich (1)H and (13)C NMR spectra of a series of systematically modified heparin derivatives uncovered underlying properties. These included the presence of interactions between residues, providing evidence that a degree of degeneracy exists in linkage geometry and that a different degree of variability exists for the two types of glycosidic linkage. The relative sensitivity of each position (C or H nucleus) in the disaccharide repeating unit to changes in O-, N-sulfation and N-acetylation was also revealed. (iii) Analysis of the (1)H NMR and CD spectra of a series of CS samples from different origins allowed their structural classification and highlighted the power of employing complementary spectroscopic methods in concert with PCA.


Asunto(s)
Sulfatos de Condroitina/química , Glicosaminoglicanos/química , Heparina/química , Dicroismo Circular , Resonancia Magnética Nuclear Biomolecular , Análisis de Componente Principal
17.
Chemosphere ; 70(11): 2092-8, 2008 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-17936330

RESUMEN

(13)C CP-MAS NMR spectroscopy is a technique that has proved to be useful in studying soil organic matter (SOM). Nevertheless, NMR spectra exhibit a weak signal and have very low resolution due to: the low natural abundance of (13)C (1.1% of C) in SOM, the generally low SOM content of soils, and the presence of paramagnetic impurities. This paper studies the effects of soil chemical pre-treatments on (13)CP-MAS NMR spectra quality and spectra representativity i.e. soil C mass balance. After chemical pre-treatment to increase total organic carbon (TOC) content and C/Fe ratio, eight soils characterized by different levels of organic carbon content and C/Fe ratios were studied using (13)CP-MAS NMR. Moreover, where chemical treatments were not applicable due to high carbon losses, the number of (13)CP-MAS NMR scans was increased in order to obtain satisfactory spectra. Results show that chemical pre-treatment of soils with C/Fe>1 caused high C losses. Bulk soils were therefore studied by increasing the number of (13)CP-MAS NMR scans. Acceptable spectra were obtained from 8K scans (1K=1024 transient). On the other hand, even when a large number of scan (32K) are used, soil with C/Fe<1 cannot be studied. As these soils are characterized by low C losses after HCl treatments (range of 2.9-25.4%), a pre-treatment of at least 1.39 mol l(-1) HCl removes excess Fe and at the same time increases C/Fe ratio resulting in 32K scans providing good spectra.


Asunto(s)
Carbono/análisis , Hierro/análisis , Suelo/análisis , Isótopos de Carbono , Ácido Clorhídrico/química , Ácido Fluorhídrico/química , Espectroscopía de Resonancia Magnética
18.
Biotechnol Biofuels ; 10: 201, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28852422

RESUMEN

BACKGROUND: In Europe, almost 87.6 million tonnes of food waste are produced. Despite the high biological value of food waste, traditional management solutions do not consider it as a precious resource. Many studies have reported the use of food waste for the production of high added value molecules. Polyhydroxyalkanoates (PHAs) represent a class of interesting bio-polyesters accumulated by different bacterial cells, and has been proposed for production from the organic fraction of municipal solid waste (OFMSW). Nevertheless, until now, no attention has been paid to the entire biological process leading to the transformation of food waste to organic acids (OA) and then to PHA, getting high PHA yield per food waste unit. In particular, the acid-generating process needs to be optimized, maximizing OA production from OFMSW. To do so, a pilot-scale Anaerobic Percolation Biocell Reactor (100 L in volume) was used to produce an OA-rich percolate from OFMSW which was used subsequently to produce PHA. RESULTS: The optimized acidogenic process resulted in an OA production of 151 g kg-1 from fresh OFMSW. The subsequent optimization of PHA production from OA gave a PHA production, on average, of 223 ± 28 g kg-1 total OA fed. Total mass balance indicated, for the best case studied, a PHA production per OFMSW weight unit of 33.22 ± 4.2 g kg-1 from fresh OFMSW, corresponding to 114.4 ± 14.5 g kg-1 of total solids from OFMSW. PHA composition revealed a hydroxybutyrate/hydroxyvalerate (%) ratio of 53/47 and Mw of 8∙105 kDa with a low polydispersity index, i.e. 1.4. CONCLUSIONS: This work showed how by optimizing acidic fermentation it could be possible to get a large amount of OA from OFMSW to be then transformed into PHA. This step is important as it greatly affects the total final PHA yield. Data obtained in this work can be useful as the starting point for considering the economic feasibility of PHA production from OFMSW by using mixed culture.

19.
Carbohydr Polym ; 117: 400-407, 2015 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-25498652

RESUMEN

An attractive strategy for ameliorating symptoms arising from the multi-faceted processes of excessive and/or continual inflammation would be to identify compounds able to interfere with multiple effectors of inflammation. The well-tolerated pharmaceutical, heparin, is capable of acting through several proteins in the inflammatory cascade, but its use is prevented by strong anticoagulant activity. Derivatives of heparin involving the periodate cleavage of 2,3 vicinal diols in non-sulfated uronate residues (glycol-split) and replacement of N-sulphamido- with N-acetamido- groups in glucosamine residues, capable of inhibiting neutrophil elastase activity in vitro, while exhibiting attenuated anticoagulant properties, have been identified and characterised. These also interact with two other important modulators of the inflammatory response, IL-8 and TNF-alpha. It is therefore feasible in principle to modulate several activities, while minimising anticoagulant side effects, providing a platform from which improved anti-inflammatory agents might be developed.


Asunto(s)
Anticoagulantes/farmacología , Heparina/análogos & derivados , Heparina/farmacología , Inflamación/tratamiento farmacológico , Proteínas Inhibidoras de Proteinasas Secretoras/farmacología , Anticoagulantes/síntesis química , Anticoagulantes/química , Relación Dosis-Respuesta a Droga , Ensayo de Inmunoadsorción Enzimática , Heparina/síntesis química , Heparina/química , Humanos , Inflamación/metabolismo , Interleucina-8/análisis , Elastasa de Leucocito/antagonistas & inhibidores , Elastasa de Leucocito/metabolismo , Proteínas Inhibidoras de Proteinasas Secretoras/síntesis química , Proteínas Inhibidoras de Proteinasas Secretoras/química , Relación Estructura-Actividad
20.
FEMS Microbiol Lett ; 230(1): 47-52, 2004 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-14734165

RESUMEN

The two main polysaccharides from the basidiomycetous fungus Laetiporus sulphureus were isolated, purified and characterized. The structural assignments were carried out using (13)C, (1)H, and (1)H,(13) HSQC nuclear magnetic resonance spectroscopy, methylation analysis, and Smith degradation. One was a linear beta-glucan having a (1-->3)-linked main chain, namely laminaran. The other was a fucomannogalactan, which consisted of a main chain of (1-->6)-linked alpha-D-galactopyranosyl residues, a part of them being substituted at O-2 by 3-O-D-mannopyranosyl-L-fucopyranosyl, alpha-D-mannopyranosyl and in a minor proportion, alpha-L-fucopyranosyl groups. This heteropolysaccharide is related to those of other Basidiomycetes heterogalactans, although it differs distinctly in its side-chain structures. Whereas part of the single-unit L-fucopyranosyl and/or 3-O-alpha-mannopyranosyl-L-fucopyranosyl residues are present as side chains of the other heterogalactans, additional alpha-D-mannopyranosyl units are present in our fucomannogalactan of L. sulphureus.


Asunto(s)
Galactanos/análisis , Glucanos/análisis , Polyporales/química , Secuencia de Carbohidratos , Galactanos/química , Galactanos/aislamiento & purificación , Glucanos/aislamiento & purificación , Espectroscopía de Resonancia Magnética , Datos de Secuencia Molecular , Polyporales/crecimiento & desarrollo
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