Copper-uptake mediated by an ecofriendly zwitterionic ionic liquid: A new challenge for a cleaner bioeconomy.

This study aims to investigate the ability of an imidazolium biobased Zwitterionic Ionic Liquids (ZILs) in enhancing the phytoavailability of copper from garden (G) and vineyard (V) soils using the model plant ryegrass. Uncontaminated and artificially contaminated CuSO4 soils, unamended and ZIL-amended soil modalities were designed. The copper/ZIL molar ratio (1/4) introduced was rationally established based on molecular modeling and on the maximal copper concentration in artificially contaminated soil. Higher accumulation of copper in the shoots was detected for the uncontaminated and copper contaminated ZIL amended V soils (18.9 and 23.3 mg/kg, respectively) contrary to G soils together with a ZIL concentration of around 3% (W/W) detected by LC-MS analyses. These data evidenced a Cu-accumulation improvement of 38% and 66% compared to non-amended V soils (13.6 and 13.9 mg/kg respectively). ZIL would be mainly present under Cu(II)-ZIL4 complexes in the shoots. The impact on the chemical composition of shoot was also studied. The results show that depending on the soils modalitity, the presence of free copper and/or ZIL led to different chemical compositions in lignin and monomeric sugar contents. In the biorefinery context, performances of enzymatic hydrolysis of shoots were also related to the presence of both ZIL and copper under free or complex forms. Ecotoxicity assessment of the vineyard soil samples indicated that the quantity of copper and ZIL remaining in the soils had no significant toxicity. ZIL amendment in a copper-contaminated soil was demonstrated as being a promising way to promote the valorization of phytoremediation plants.

Mass Spectrometry, Ion Mobility Separation and Molecular Modelling: A Powerful Combination for the Structural Characterisation of Substituted Cyclodextrins Mixtures.

When working on the synthesis of substituted cyclodextrins (CDs), the main challenge remains the analysis of the reaction media content. Our objective in this study was to fully characterise a complex isomers mixture of Lipidyl-ßCDs (LipßCD) obtained with a degree of substitution 1 (DS = 1) from a one-step synthesis pathway. The benefit of tandem mass spectrometry (MS/MS) and ion mobility separation hyphenated with mass spectrometry (IM-MS) was investigated. The MS/MS fragment ion's relative intensities were analysed by principal component analysis (PCA) to discriminate isomers. The arrival time distribution (ATD) of each isomer was recorded using a travelling wave ion mobility (TWIM) cell allowing the determination of their respective experimental collision cross section (CCSexp). The comparison with the predicted theoretical CCS (CCSth) obtained from theoretical calculations propose a regioisomer assignment according to the ßCD hydroxyl position (2, 3, or 6) involved in the reaction. These results were validated by extensive NMR structural analyses of pure isomers combined with molecular dynamics simulations. This innovative approach seems to be a promising tool to elucidate complex isomer mixtures such as substituted cyclodextrin derivatives.

A simple procedure to obtain a medium-size oligogalacturonic acids fraction from orange peel and apple pomace wastes.

Pectin oligosaccharides, which can be obtained from fruit wastes, have proven their potential as plant immune-system elicitors. Although the precise size of active species is still under investigation, medium size oligosaccharides have been reported as the most active. Three defined oligogalacturonic acid (OGAs) mixtures were produced from commercial pectin, orange peel and apple pomace residues. The methodology developed involves two sequential acid treatments followed by stepwise ethanol precipitation. Without the need of chromatographic separations, three different fractions were obtained. The fractions were analyzed by high performance anion exchange chromatography (HPAEC) and were completely characterized by mass spectrometry, showing that the small size, medium size and large size fractions contained OGAs of degree of polymerization 3 to 9, 6 to 18, and 16 to 55, respectively.

Synthesis of defined oligohyaluronates-decorated liposomes and interaction with lung cancer cells.

In this work hyaluronic acid (HA) oligosaccharides with degree of polymerization (DP) 4, 6 and 8, obtained by enzymatic depolymerization of HA, were conjugated to a PEG-phospholipid moiety. The products (HA-DP4, HA-DP6 and HA-DP8) were used to prepare decorated liposomes. The cellular uptake of HA-DP4, HA-DP6 and HA-DP8-decorated fluorescently labelled liposomes was significantly higher (12 to 14-fold) in lung cancer cell lines with high CD44 expression than in those with low CD44 expression, suggesting a receptor-mediated entry of HA-conjugated formulations. Competition assays showed that the uptake followed this rank order: HA-DP8>HA-DP6>HA-DP4 liposomes. Moreover, they are capable of a faster interaction with CD44, followed by phagocytosis, than HA liposomes obtained from HA of higher molecular weight (4800 and 14800 Da). HA-DP4, HA-DP6 and HA-DP8-liposomes did not show cytotoxicity or inflammatory effects. Overall, we propose our new HA-DP oligosaccharides as biocompatible and effective tools for a potential drug delivery to CD44-positive cells.

Solvent- and catalyst-free transamidations of unprotected glycosyl carboxamides.

The transamidation reactions of unprotected mono- and disaccharidic carboxamides with various primary and secondary arylic, heterocyclic or aliphatic amines are described. This new method is green and atom efficient and gives good to high yields. Notably, the conditions do not require either a solvent or a catalyst and give ammonia as a single by-product. The described coupling reaction is compatible with a variety of functional groups and was used in the synthesis of various glycosidic derivatives and biologically relevant glycolipids. A plausible reaction mechanism involving an intermolecular H-bond activation of the starting carboxamides is proposed.

High resolution MALDI-TOF-MS and MS/MS: Application for the structural characterization of sulfated oligosaccharides.

Sulfated oligosaccharides are involved in important biological events that are often modulated by specific sequences and sulfation patterns, but their structural analysis remains challenging. Matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) analysis of three different sulfated oligosaccharides (Fondaparinux, the octasulfated pentasaccharide, a disulfated heparin-derived tetrasaccharide 1, and an octasulfated maltoheptaose) 2 was performed using the 2-(4-hydroxyphenylazo)benzoic acid-tetramethylguanidinium (HABA-TMG2) matrix. High resolution mass spectrometry of the main ions observed was successful, and this was complemented by tandem mass spectrometry (MS/MS) analysis for structural assessment. Despite sulfate losses, fully sulfated molecular ions were observed and these allowed the determination of oligosaccharide structures: UA-GlcNAc-UA(2S)-AnhMan(6S) for compound 1 and (Glc6S)6-Glc (1S,6S) for compound 2.

Unprecedented Thiacalixarene Fucoclusters as Strong Inhibitors of Ebola cis-Cell Infection and HCMV-gB Glycoprotein/DC-SIGN C-type Lectin Interaction.

Glycan-protein interactions control numerous biological events from cell-cell recognition and signaling to pathogen host cell attachment for infections. To infect cells, some viruses bind to immune cells with the help of DC-SIGN (dendritic cell [DC]-specific ICAM3-grabbing nonintegrin) C-type lectin expressed on dendritic and macrophage cell membranes, via their envelope protein. Prevention of this infectious interaction is a serious therapeutic option. Here, we describe the synthesis of the first water-soluble tetravalent fucocluster pseudopeptide-based 1,3-alternate thiacalixarenes as viral antigen mimics designed for the inhibition of DC-SIGN, to prevent viral particle uptake. Their preparation exploits straightforward convergent strategies involving one-pot Ugi four-component (Ugi-4CR) and azido-alkyne click chemistry reactions as key steps. Surface plasmon resonance showed strong inhibition of DC-SIGN interaction properties by tetravalent ligands designed with high relative potencies and ß avidity factors. All ligands block DC-SIGN active sites at nanomolar IC50 preventing cis-cell infection by Ebola viral particles pseudotyped with EBOV glycoprotein (Zaire species of Ebola virus) on Jurkat cells that express DC-SIGN. In addition, we observed strong inhibition of DC-SIGN/human cytomegalovirus (HCMV)-gB recombinant glycoprotein interaction. This finding opens the way to the simple development of new models of water-soluble glycocluster-based thia-calixarenes with wide-ranging antimicrobial activities.

Arylnaphthalene and aryltetralin-type lignans in hairy root cultures of Linum perenne, and the stereochemistry of 6-methoxypodophyllotoxin and one diastereoisomer by HPLC-MS and NMR spectroscopy.

INTRODUCTION: Hairy root cultures of Linum sp. are an alternative for the high production of lignans. Linum perenne is known to produce arylnaphthalene-type lignans such as justicidin B, isojusticidin and diphyllin. OBJECTIVE: To elucidate the presence of aryltetralin-type lignan diastereoisomers, besides the known arylnaphthalene-type lignans, in hairy roots of Linum perenne, and to determine the configurations of one diastereoisomer of 6-methoxypodophyllotoxin (6-MPTOX). METHODS: Lignans from hairy root cultures of Linum perenne were extracted and separated by HPLC. Arylnaphthalene-type lignans were identified by LC-MS, according to the literature. Two diastereoisomers of aryltetralin-type lignans were analysed by mass spectrometry and NMR spectroscopy. RESULTS: Numerous arylnaphthalene-type lignans (diphyllin-2-hexose-pentose, diphyllin-3-pentose and diphyllin-hexose) were identified in hairy root cultures. Methoxypodophyllotoxin, an aryltetralin-type lignan, was also identified, as well as one diastereoisomer. This aryltetralin-type lignan could be derived via 7-hydroxymatairesinol as a hypothetical biosynthetic pathway. The stereochemical configurations of aryltetralin isomers were determined. CONCLUSION: Arylnaphthalene and two diastereoisomers of aryltetralin-type lignans are produced in Linum perenne hairy root cultures. Matairesinol, the precursor of justicidin B, also seems to be converted into 6-MPTOX via 7-hydroxymatairesinol. This is the first report of the stereochemical configurations of an aryltetralin-type lignan other than podophyllotoxin (PTOX).

o-Xylylene protecting group in carbohydrate chemistry: application to the regioselective protection of a single vic-diol segment in cyclodextrins.

A systematic study of the suitability of α,α'-dibromo-o-xylene as a reagent for cyclic o-xylylene protection of vic-diols in different monosaccharide substrates is reported. The installation of this protecting group, formally equivalent to a di-O-benzylation reaction, proceeds with good regioselectivity toward 1,2-trans-diequatorial diol systems in pyranose and furanose rings. Initially, the benzyl ether-type derivative of the more acidic hydroxyl is preferentially formed. Subsequent intramolecular etherification toward the equatorial-oriented vicinal OH is kinetically favored. The methodology has been implemented for the simultaneous protection of the secondary O-2 and O-3 positions of a single d-glucopyranosyl unit in cyclic oligosaccharides of the cyclodextrin (CD) family (cyclomaltohexa-, -hepta-, and -octaose; α, ß, and γCD).

Preparative separation of glycoalkaloids α-solanine and α-chaconine by centrifugal partition chromatography.

The main glycoalkaloids of a commercial potato cultivar, α-chaconine and α-solanine, were extracted from sprouts of Solanum tuberosum cv. Pompadour by a mixture of MeOH/H(2)O/CH(3)COOH (400/100/50, v/v/v). In these conditions, 2.8±0.62g of crude extract were obtained from 50g of fresh sprouts and the total glycoalkaloid content was determined by analytical HPLC at 216.5mg/100g. α-Chaconine and α-solanine were separated in a preparative scale using centrifugal partition chromatography (CPC). In a solvent system composed of a mixture of ethyl acetate/butanol/water (15/35/50, v/v/v), α-chaconine (54mg) and α-solanine (15mg) were successfully isolated from the crude extract in one step of purification. The purity of isolated compounds was determined to be higher than 92% by HPLC analysis.

Molecular imprinting technology for specific recognition of heparan sulfate like disaccharides.

Iinteractions of biologically active proteins with sulfated glycans, particularly heparan sulfates (HS), are dependent on factors involving amounts and positions of the sulfate groups in the sugars chains. Although the importance of knowing the exact positions of the sulfate groups in particular HS sequences is well recognized, at present, approaches in this area are complex and still considered as a challenge. Here, we investigated the applicability of the 'Molecular Imprinting Technology' for the generation of imprinted polymers able to specifically recognize a model HS-like disaccharide. In order to advance on the applicability of this technology to the recognition of these complex sugars, we prepared a library of imprinted polymers to investigate the impact of the polymerization reaction conditions and stoichiometry on the generation of binding sites able to specifically recognize the model sulfated sugar. Our results show that imprinted polymers able to specifically bind HS-like saccharide can readily be obtained. This constitutes a suitable option for developing novel strategies directed to study fine sulfated sugars structures.

Synthesis and immunochemical evaluation of a non-methylated disaccharide analogue of the anthrax tetrasaccharide.

Anthrax tetrasaccharide is an oligosaccharide expressed at the outermost surface of the Bacillus anthracis spores, featuring three rhamnoses and a rare sugar called anthrose. This motif has now been identified as a plausible component of future human vaccines against anthrax. We report herein the synthesis of a 2-O-demethylated-ß-D-anthropyranosyl-(1→3)-α-L-rhamnopyranose disaccharide analogue of this tetrasaccharide from a cyclic sulfate intermediate. This disaccharide conjugated to BSA induces an anti-native tetrasaccharide IgG antibody response when administered in BALB/c mice. Moreover, induced sera bound to native B. anthracis endospores. These results suggest that the disaccharide analogue, easily amenable for a synthetic scale-up, could be used in a glycoconjugate antigen formulation.

Norlittorine and norhyoscyamine identified as products of littorine and hyoscyamine metabolism by (13)C-labeling in Datura innoxia hairy roots.

The presence of two compounds, norlittorine and norhyoscyamine, has been reported in leaves and roots of Datura innoxia; however their metabolic origin in the tropane alkaloid pathway has remained unknown. Precise knowledge of this pathway is a necessary pre-requisite to optimize the production of hyoscyamine and scopolamine in D. innoxia hairy root cultures. The exact structure of norlittorine and norhyoscyamine was confirmed by LC-MS/MS and NMR analyses. Isotopic labeling experiments, using [1-(13)C]-phenylalanine, [1'-(13)C]-littorine and [1'-(13)C]-hyoscyamine, combined with elicitor treatments, using methyl jasmonate, coronalon and 1-aminocyclopropane-1-carboxylic acid, were used to investigate the metabolic origin of the N-demethylated tropane alkaloids. The results suggest that norlittorine and norhyoscyamine are induced under stress conditions by conversion of littorine and hyoscyamine. We propose the N-demethylation of tropane alkaloids as a mechanism to detoxify cells in overproducing conditions.

A click procedure with heterogeneous copper to tether technetium-99m chelating agents and rhenium complexes. Evaluation of the chelating properties and biodistribution of the new radiolabelled glucose conjugates.

An efficient protocol was developed to tether chelating agents and rhenium complexes onto a glucoside scaffold with a heterogeneous copper catalyst via click chemistry. The supported catalyst avoids the formation of unwanted copper complexes during the cyclisation step. The possibility to graft a pre-chelated M(CO)(3) core by click chemistry onto a biomolecule was highlighted for the first time. (99m)Tc(CO)(3)-glucoconjugates displayed excellent in vitro stability, a fast in vivo blood clearance and a low specific organ uptake or long-term retention in spleen and stomach.

Exopolysaccharide production by nitrogen-fixing bacteria within nodules of Medicago plants exposed to chronic radiation in the Chernobyl exclusion zone.

Nitrogen-fixing bacteria isolated from root nodules of Medicago plants growing in the 10 km zone around the Chernobyl nuclear power plant were screened for the production of new water-soluble acidic exopolysaccharides (EPSs). The different strains belonged to the Enteriobacteriaceae family (Enterobacter ludwigii, Raoultella terrigena, Klebsiella oxytoca), except for one which belonged to the Rhizobiaceae family (Sinorhizobium meliloti). All of the bacteria produced highly viscous EPS with an average molecular weight comprised between 1 x 10(6) and 3 x 10(6) Da. Five different compositions of EPS were characterized by physico-chemical analyses and (1)H NMR spectroscopy: galactose/mannose (2/1), galactose/glucose (1/1), galactose/glucose/mannose (1/2/1), fucose/galactose/glucose (2/1/1) and fucose/galactose/glucose/mannose (2/2/1/1 or 1/1/2/4). Glucuronic acid, a charged monosaccharide, was also recovered in most of the different EPSs.

Regioselective access to 3I-O-substituted-beta-cyclodextrin derivatives.

Formation of a copper(ii)-beta-cyclodextrin (beta-CD) complex in an aqueous medium allowed the regioselective introduction into the oligosaccharide of a benzyl or a bromo-allyl substituent at O-3.

Efficient regioselective chemical modifications of maltotriose: an easy access to oligosaccharidic scaffold.

Regioselective chlorination of fully unprotected maltotriose has given in high yield 1(I),2(I-III),3(I-III),4(III)-octa-O-acetyl-6(I-III)-trichloro-6(I-III)-trideoxymaltotriose. Moreover, regioselective ditritylation of methyl ß-maltotrioside has provided the two regioselectively C(6)-disubstituted trisaccharides. Selective deprotection of these new compounds gives the corresponding diol and halogenated analogues, respectively, in good yield. All compounds have been completely characterized and the substitution pattern in the oligosaccharidic sequence has been elucidated. A new family of amphiphilic carbohydrates, namely the 6-deoxy-6-alkylthiomaltotriose derivatives, bearing either two or three thioalkyl hydrophobic chains, respectively, has been synthesized. Critical micellar concentration (CMC) values as well as the antimicrobial properties have been evaluated for amphiphilic compounds.

The Arabidopsis sweetie mutant is affected in carbohydrate metabolism and defective in the control of growth, development and senescence.

SUMMARY: Sugars modulate many vital metabolic and developmental processes in plants, from seed germination to flowering, senescence and protection against diverse abiotic and biotic stresses. However, the exact mechanisms involved in morphogenesis, developmental signalling and stress tolerance remain largely unknown. Here we report the characterization of a novel Arabidopsis thaliana mutant, sweetie, with drastically altered morphogenesis, and a strongly modified carbohydrate metabolism leading to elevated levels of trehalose, trehalose-6-phosphate and starch. We additionally show that the disruption of SWEETIE causes significant growth and developmental alterations, such as severe dwarfism, lancet-shaped leaves, early senescence and flower sterility. Genes implicated in sugar metabolism, senescence, ethylene biosynthesis and abiotic stress were found to be upregulated in sweetie. Our physiological, biochemical, genetic and molecular data indicate that the mutation in sweetie was nuclear, single and recessive. The effects of metabolizable sugars and osmolytes on sweetie morphogenesis were distinct; in light, sweetie was hypersensitive to sucrose and glucose during vegetative growth and a partial phenotypic reversion took place in the presence of high sorbitol concentrations. However, SWEETIE encodes a protein that is unrelated to any known enzyme involved in sugar metabolism. We suggest that SWEETIE plays an important regulatory function that influences multiple metabolic, hormonal and stress-related pathways, leading to altered gene expression and pronounced changes in the accumulation of sugar, starch and ethylene.

Efficient purification of small unsaturated oligoglucuronides by reversed-phase chromatography.

Ion-exchange chromatography has been applied to purification of unsaturated oligoglucuronans. After an isocratic elution on a strong anion-exchange column, the collected fractions were desalted by low pressure size exclusion chromatography. However, this efficient separation was limited by the time required to desalt. So, we developed a reversed-phase chromatography method using back ionization of oligomers. Two C18 columns were tested with trifluoroacetic acid (TFA 0.7%) as eluent. Different selectivities and column stabilities were observed in this acidic condition. The scale up for semi-preparative applications enabled us to recover pure unsaturated oligoglucuronans without desalting step.