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Gelatin is a costless polypeptide material of natural origin, able to form hydrogels that are potentially useful in biomaterial scaffold design for drug delivery, cell cultures, and tissue engineering. However, gelatin hydrogels are unstable at physiological conditions, losing their features only after a few minutes at 37 °C. Accordingly, treatments to address this issue are of great interest. In the present work, we propose for the first time the use of bi- and trifunctional tetrazoles, most of them unknown to date, for photoinduced gelatin cross-linking towards the production of physiologically stable hydrogels. Indeed, after UV-B irradiation, aryl tetrazoles generate a nitrilimine intermediate that is reactive towards different functionalities, some of them constitutively present in the amino acid side chains of gelatin. The efficacy of the treatment strictly depends on the structure of the cross-linking agent used, and substantial improved stability was observed by switching from bifunctional to trifunctional cross-linkers.

In order to improve collagen bioactivity for regenerative medicine approaches, thymosin-β4 (Tβ4P) and Human Vitronectin (HVP) derived peptides are grafted to collagen by thiol-ene Michael addition. Tβ4P and HVP are known to exert a pro-angiogenic and a pro-adhesive activity respectively and HVP is involved in osteogenesis promotion. The ability of these peptides to increase collagen cell adhesion and angiogenesis properties is assessed on human cell lines. In particular, HVP-grafted collagen increased human osteoblast adhesion and cell proliferation: after 24 h, both adhesion and proliferation roughly showed a 4-fold increase, if compared to pristine collagen. Tβ4P-grafted collagen promotes Vascular Endothelial Growth Factor (VEGF) gene expression in human vascular cell lines by more than 7 times. These results suggest that HVP-grafted collagen may be an interesting biomaterial for bone tissue regeneration, while Tβ4P-grafted collagen is useful for angiogenesis promotion.

The ability of gelatin-based hydrogels of incorporating and releasing under controlled conditions 5,6-dihydroxyindole-2-carboxylic acid (DHICA), a melanin-related metabolite endowed with marked antioxidant properties was investigated. The methyl ester of DHICA, MeDHICA, was also tested in view of its higher stability, and different solubility profile. Three types of gelatin-based hydrogels were prepared: pristine porcine skin type A gelatin (HGel-A), a pristine gelatin cross-linked by amide coupling of lysines and glutamic/aspartic acids (HGel-B), and a gelatin/chitosan blend (HGel-C). HGel-B and HGel-C differed in the swelling behavior, showed satisfactorily high mechanical strength at physiological temperatures and well-defined morphology. The extent of incorporation into all the gelatins tested using a 10% w/w indole to gelatin ratio was very satisfactory ranging from 60 to 90% for either indoles. The kinetics of indole release under conditions of physiological relevance was evaluated up to 72 h. The highest values were obtained with HGel-B and HGel-C for MeDHICA (90% after 6 h), and an appreciable release was observed for DHICA reaching 30% and 40% at 6 h for HGel-B and HGel-C, respectively. At 72 h, DHICA and MeDHICA were released at around 30% from HGel-A at pH 7.4, with an increase up to 40% at pH 5.5 in the case of DHICA. DHICA incorporated into HGel-B proved fairly stable over 6 h whereas the free compound at the same concentration was almost completely oxidized. The antioxidant power of the indole loaded gelatins was monitored by chemical assays and proved unaltered even after prolonged storage in air, suggesting that the materials could be prepared in advance with respect to their use without alteration of their efficacy.

Glycans influence a variety of aspects of tissue development and pathophysiology, harboring a wealth of biochemical information exploitable for the discovery of new biomarkers. The development of versatile and precise glycoanalytical platforms is crucial to bring to the scientific community reliable tools to unveil the glycan- encoded biochemical information. In this work, a novel platform for brain glycan analysis, named Lysate in-Solution Deglycosylation (LSD), is presented, validated and compared to similar methodologies reported in the literature. Briefly, within the LSD workflow, brain tissue is lysed, proteins are purified via methanol/chloroform extraction, and directly deglycosylated with PNGase F. Released N- glycans are purified using a second round of methanol/chloroform extraction, labelled with fluorescent tags, and cleaned-up prior to LC- FLR/MS analysis. LSD is a quick, sensitive, robust, precise, specific and versatile glycomic workflow, compatible with multiple glyco(proteo)mics analyses of the same sample and eventually applicable to other solid tissues. LSD was devised as a plug-and-play platform for quick glycosylation analysis, and was designed to be compatible with a variety of analytical set-ups (i.e., diverse detection systems), thus enabling the extraction of an additional layer of information from different studies (i.e., proteomics) without the need to collect fresh biological materials. In comparison to analogous N-glycomic workflows, LSD performs reliably on the smallest amount of starting brain tissue and, to the best of the authors' knowledge, is currently the most thoroughly validated neuro-N- glycomic method in the field-related literature, thus representing a significant step forward on the road towards glycan-based biomedical applications.

Carbohydrates are one of the most powerful and versatile classes of biomolecules that nature uses to regulate organisms’ biochemistry, modulating plenty of signaling events within cells, triggering a plethora of physiological and pathological cellular behaviors. In this framework, glycan carrier systems or carbohydrate-decorated materials constitute interesting and relevant tools for medicinal chemistry applications. In the last few decades, efforts have been focused, among others, on the development of multivalent glycoconjugates, biosensors, glycoarrays, carbohydrate-decorated biomaterials for regenerative medicine, and glyconanoparticles. This review aims to provide the reader with a general overview of the different carbohydrate carrier systems that have been developed as tools in different medicinal chemistry approaches relying on carbohydrate-protein interactions. Given the extent of this topic, the present review will focus on selected examples that highlight the advancements and potentialities offered by this specific area of research, rather than being an exhaustive literature survey of any specific glyco-functionalized system.

The emerging trends in regenerative medicine rely among others on biomaterial-based therapies, with the use of biomaterials as a central delivery system for biochemical and physical cues to manipulate transplanted or ingrowth cells and to orchestrate tissue regeneration. Cell adhesion properties of a biomaterial strongly depend on its surface characteristics. Among others poly(e-caprolactone) (PCL) is a biocompatible and biodegradable material with low cytotoxicity that is widely adopted as synthetic polymer in several applications. However, it is hydrophobic, which limits its use in tissue engineering. In order to improve its hydrophilicity and cellular compatibility, PCL surface was grafted with maltose through a two-step procedure in which controlled aminolysis of PCL ester bonds by hexanediamine was followed by reductive amination with the carbohydrate reducing end. The modified PCL surface was then characterized in detail by x-ray Photoelectron Spectroscopy (XPS) and Near Edge x-ray Absorption Fine Structure (NEXAFS) spectroscopies. In addition, the biocompatibility of the proposed biomaterial was investigated in preliminary biological assays.

The synthesis of novel hyperbranched monodisperse linear dendrimers, based on 2,2-bis-(hydroxymethyl)-propionic acid (bis-MPA), has been achieved by convergent metathesis-mediated coupling between the alkene-terminated focal point of bis-MPA dendrons. On their surface, dendrimers present 4, 8 and 16 functional groups. Glycodendrimers exposing multiple saccharide moieties have also been obtained. To the best of our knowledge, this is the first example of the use of metathesis for focal point coupling.

Hybrid materials, with co-networks of organic and inorganic components, are increasing in popularity due to their tailorable degradation rates and mechanical properties. To increase mechanical stability, particularly in water, covalent bonding must occur between the components. This can be introduced using crosslinking agents such as 3-glycidoxypropyl trimethoxysilane (GPTMS). Attachment of GPTMS to polymers in aqueous conditions is hypothesized to occur by opening of the epoxide ring by nucleophiles on the polymer chain. Despite side reactions that occur between the epoxide ring of GPTMS and water, a range of NMR techniques showed that the carboxylic acid group of poly(γ-glutamic acid) reacted with GPTMS. This result was used to identify the amino acids in gelatin that reacted most rapidly with the GPTMS epoxide ring, confirming that covalent bonding occurred in gelatin–silica hybrid materials.

The synthesis of new dendrons of the generations 0, 1 and 2 with a double bond at the focal point and a carbonyl group at the termini has been carried out. The carbonyl group has been exploited for the multivalent conjugation to a sample saccharide by reductive amination and alkoxyamine conjugation. © 2014 Bini et al; licensee Beilstein-Institut.

Collagen matrices have been neoglycosylated with lactose by reductive amination at lysine side chains. AFM analysis highlights that the chemical neoglycosylation does not affect molecular assembly into fibrils. Moreover, ELLA biochemical assays show that the glycan moiety is efficiently exposed on the matrix surface for receptor recognition.

A set of new metabolically stable arabinose 5-phosphate analogues possessing phosphate mimetic groups at position 5 was synthesised. Their ability to interact with arabinose 5-phosphate isomerase from Pseudomonas aeruginosa was evaluated by STD-NMR studies. The synthesised compounds were also characterised for their activity in vivo on P. aeruginosa and Escherichia coli strains. Unfortunately, none of the synthesised compounds was able neither to bind API nor to inhibit bacterial growth.

Despite the relevance of carbohydrates as cues in eliciting specific biological responses, glycans have been rarely exploited in the study of neuronal physiology. We report thereby the study of the effect of neoglucosylated collagen matrices on neuroblastoma F11 cell line behavior. Morphological and functional analysis clearly showed that neoglucosylated collagen matrices were able to drive cells to differentiate. These data show for the first time that F11 cells can be driven from proliferation to differentiation without the use of chemical differentiating agents. Our work may offer to cell biologists new opportunities to study neuronal cell differentiation mechanisms in a cell environment closer to physiological conditions.

Biomaterial surface properties, via introduction of specific signal biomolecules can influence cell adhesion and differentiation processes. Inspired by the monosaccharide motifs found in collagen glycosylation patterns, galactose being one of the most commonly found saccharidic residues, collagen matrices were modified in order to expose galactose residues to cells. The interaction of chemically neoglycosylated matrices was evaluated with osteosarcoma-derived cell line MG63.

Hybrid materials with interpenetrating networks of silica and degradable polymers have the potential to outperform current biomaterials as their mechanical properties and degradation rates can be tightly controlled. GPTMS is one of the most widely used precursors for sol–gel hybrid fabrication. It can be used as the silica precursor or as a coupling agent to create hybrids with covalent bonds between the silica and organic components. Understanding its reactivity with nucleophilic groups on organic molecules in aqueous conditions is of key importance to hybrid synthesis. NMR spectrometry assisted by mass spectrometry was successfully used for the investigation of the reaction system of (3-glycidoxypropyl)trimethoxysilane (GPTMS) in the presence of different simple nucleophiles. Inorganic condensation and silica network formation is accelerated in the presence of propylamine; propanoic acid gives nucleophilic attack on the epoxy ring; propanol and propanthiol do not seem to participate in the reaction.

The grafting of galactose units onto poly(epsilon-caprolactone) (PCL) substrates by a wet chemistry two-step procedure is proposed. Even though a reduction of hardness from 0.58-0.31 GPa to 0.12-0.05 GPa is achieved, the chemical functionalization does not negatively affect the tensile modulus (332.2 +/- 31.3 MPa and 328.5 +/- 34.7 MPa for unmodified and surface-modified PCL, respectively) and strength (15.1 +/- 1.3 MPa and 14.8 +/- 1.5 MPa as assessed before and after the surface modification, respectively), as well as the mechanical behaviour evaluated through small punch test. XPS and enzyme-linked lectin assay (ELLA) demonstrate the presence, and also the correct exposition of the saccharidic epitope on PCL substrates. The introduction of carbohydrate moieties on the PCL surfaces clearly enhances the hydrophilicity of the substrate, as the water contact angle decreases from 82.1 +/- 5.8 degrees to 62.1 +/- 4.2 degrees. Furthermore, preliminary biological analysis shows human mesenchymal stem cell viability over time and an improvement of cell adhesion and spreading. (C) 2014

Biomaterials are needed for tissue regeneration applications that provide control of mechanical properties and enhanced toughness compared to conventional bioceramics. New sol–gel hybrids were developed with interpenetrating networks of silica and bis(3-aminopropyl) polyethylene glycol. Covalent coupling between the organic and the inorganic components was used to control mechanical properties of the hybrids. The objective was to synthesise and characterise a bis(3-aminopropyl) polyethylene glycol silica hybrid material with 35 wt% organic and 65 wt% inorganic and covalent coupling between the components. A coupling agent, 3-glycidopropyltrimethoxysilane (GPTMS) was used to form the covalent links. The hypothesis was that the epoxy ring of the GPTMS would react with the polymer, leaving a polymer functionalised with siloxane groups. In a sol of hydrolysed tetraethyl orthosilicate (TEOS) the siloxanes from the GPTMS form –Si–O–Si– bonds between the functionalised polymer and the silica network. Bis(3-aminopropyl) polyethylene glycol contains two terminal amino groups available for the covalent functionalisation with the epoxy group of GPTMS. Hybrids with 35 wt% organic and 65 wt% inorganic with a ratio of GPTMS:PEG of 1:4 were proven to have an excellent balance between strain to failure (10%) and compressive strength (20 MPa). However, the functionalisation of the polymer was followed by liquid NMR as a function of the aging time and temperature and the expected reaction of nucleophilic attack of the epoxy ring by the amino group of the polymer did not happen until the water was removed from the system during drying. Increasing the amount of GPTMS decreased rate of weight loss during immersion in TRIS buffer solution.

Type I collagen films have been functionalized on their surfaces by plasma treatment with carboxyl and amino groups to improve their potential for grafting bioactive molecules. The physico-chemical properties of the plasma-treated films were evaluated and compared to the untreated materials by water contact angle, SEM and AFM. The presence of new functional groups on the film surfaces has been assessed by ATR-FTIR spectra after chemical derivatization. Moreover, the biocompatibility of the plasma-treated films was studied with MG-63 human osteoblast-like cells, evaluating cell proliferation, viability and morphology at 1, 3 and 7. days. © 2012 Elsevier Inc.

Molecular recognition of glycans plays an important role in glycomic and glycobiology studies. For example, pathogens have a number of different types of lectin for targeting host sugars. In bacteria, lectins exist sometimes as domains of bacterial toxins and exploit adhesion to glycoconjugates as a means of entering host cells. Herein, we describe the synthesis of three glycodendrons with the aim to dissect the fine structural details involved in the multivalent carbohydrate-protein interactions. LecA, from the pathogen Pseudomonas aeruginosa, has been used to characterize galactose dendrons interaction using one of the most widespread NMR technique for the elucidation of receptor-ligand binding in solution, the saturation transfer difference (STD) NMR. Furthermore, the effective hydrodynamic radius of each dendrimer recognized by LecA was estimated from the diffusion coefficients determined by pulsed-field-gradient stimulated echo (PFG-STE) NMR experiments.

A hands-on approach to introduce the chemical elements and the atomic structure to elementary/middle school students is described. The proposed classroom activity presents Bohr models of atoms using common and inexpensive materials, such as nested plastic balls, colored modeling clay, and small-sized pasta (or small plastic beads).

The serine-threonine protein kinase Akt, also known as protein kinase B, is a key component of the phosphoinositide 3-kinase (PI3K)-Akt-mTOR axis. Deregulated activation of this pathway is frequent in human tumors and Akt-dependent signaling appears to be critical in cell survival. PI3K activation generates 3-phosphorylated phosphatidylinositols that bind Akt pleckstrin homology (PH) domain. The blockage of Akt PH domain/phosphoinositides interaction represents a promising approach to interfere with the oncogenic potential of over-activated Akt. In the present study, phosphatidyl inositol mimics based on a β-glucoside scaffold have been synthesized as Akt inhibitors. The compounds possessed one or two lipophilic moieties of different length at the anomeric position of glucose, and an acidic or basic group at C-6. Docking studies, ELISA Akt inhibition assays, and cellular assays on different cell models highlighted 1-O-octadecanoyl-2-O-β-d-sulfoquinovopyranosyl-sn-glycerol as the best Akt inhibitor among the synthesized compounds, which could be considered as a lead for further optimization in the design of Akt inhibitors.

Lipopolysaccharides (LPSs), which constitute the lipid portion of the outer leaflet of Gram-negative bacteria, are essential for growth, and are responsible for a variety of biological effects associated with Gram-negative sepsis. LPSs are amphiphilic molecules comprising three regions: lipid A, the core region, and a polysaccharide portion; the lipid A was proven to represent the toxic principle of endotoxic active lipopolysaccharides. In addition, it is known that the minimal conserved structure of LPS is the lipophylic oligoasaccharidic structure containing Kdo residues linked to the-LipA moiety. Thus, the design and development of novel antibacterial drugs can focus on different aspects, related to the biosynthesis and chemical features of LPS: 1) Inhibitors of lipid A biosynthesis 2) Inhibitors of Kdo biosynthesis. Both Kdo and Lipid A are needed for the construction of the minimum structural element Kdo2-LipidA, needed for bacterial survival. Any inhibitors acting on the biogenetic pathway of this molecule can act as antibacterial. 3) Antagonists of the interaction between endotoxins and the host receptors: LPS is recognised by the CD14 and the Toll-like receptor (TLR)-4/MD2 complex, where Lipid A is the crucial moiety in the interaction. Any drug acting as an antagonist of this process can have antisepsis potential. Considerable efforts have been made in this direction to identify natural or synthetic molecules able to interfere with the interaction between LPS and inflammatory cells. This review will highlight recent efforts in the design and biological activity of enzyme inhibitors and antagonist acting on the 3 key aspects outlined above.

Synthesis of a library of pyrrolo[2,1-c][1,4]-benzodiazepines derived from spiro bicyclic d- or l-proline analogues containing a d- or l-fructose moiety was developed. The l-fructose moiety was obtained by using a new synthetic pathway starting from l-arabinose through a six steps synthesis in 18% overall yield. Molecular modeling calculations and DNMR studies showed that d- and l-fructose-based pyrrolobenzodiazepines exhibit a rigid (P)- and (M)-helical conformation, respectively, in which the C-11a substituent was always pseudoequatorial. Additionally, pyrrolobenzodiazepines functionalized with a chloride, bromide, nitro, or amino group in the benzene ring, with or without N-methylation and with or without protection of sugar alcohol groups, allowed a relationship between the molecular structure and biological activity to be established. The conformation of the diazepam ring was not the sole key player influencing binding affinities, and the sugar moiety can in some cases increase the binding activity, possibly by participating in the binding event. Finally, these compounds have increased the understanding of the differential recognition of (M)-/(P)-helical benzodiazepines on GABAA receptor. © 2011 American Chemical Society.

In this article we review our work over the years on carbohydrates and carbohydrate mimetics and their applications in medicinal chemistry. In the first part of the review innovative synthetic methods, such as the chemoselective glycosylation method originally developed by our group and its applications to the synthesis of neoglycoconjugates (neoglycopeptides, oligosaccharide mimetics, neoglycolipids, etc...) will be presented. The high density of functional groups (hydroxyls) on the monosaccharides and the structural role of sugars forming the core of complex glycans in scaffolding and orienting the external sugar units for the interaction with receptors, inspired us and others to use sugars as scaffolds for the construction of pharmacologically active compounds. In the second part of this review, we will present some examples of bioactive and pharmacologically active compounds obtained by decorating monosaccharide scaffolds with pharmacophore groups. Sugar-derived protein ligands were also used as chemical probes to study the interaction of their target with other proteins in the cell. In this context, sugar mimetics and sugar-derived compounds have been employed as tools for exploring biology according to the "chemical genetic" approach.

Carminic acid, a natural hydrophilic dye extensively used in the food and cosmetic industries, is converted in hydrophobic dyes by acetylation or pivaloylation. These derivatives are successfully used as biocolourants for rubber objects. In this paper, spectroscopic properties of the carminic acid derivatives in dimethyl sulfoxide and in polybutylacrylate are studied by means of photoluminescence and time-resolved photoluminescence decays, revealing a hypsochromic effect due to the presence of bulky substituents as the acetyl or pivaloyl groups. Molecular mechanics and density functional theory calculations confirm the disruption of planarity between the sugar ring and the anthraquinoid system determined by the esterification.

Small molecules altering protein functions as inhibitors, agonists or antagonists, find application in systems biology enabling an analysis of the in vivo consequences of these alterations. In this context carbohydrates are ideal tools, not only because they are involved in a variety of recognition phenomena of biological relevance, but also because they are ideal scaffolds to generate libraries of bioactive compounds. Examples of design, synthesis and biological assays of different carbohydrate based inhibitors or protein ligands are reported. Exploiting NMR methods, the binding between a small molecules (inhibitor or ligand) and a protein can be detected, the affinity measured, and the interaction topology defined. This set of information is useful not only to clarify the mechanism of protein-ligand interaction, but also to improve the design of new inhibitors/ligands. The multifunctionality and the conformational rigidity of carbohydrates make this class of compounds the ideal scaffolds to generate libraries exploiting the combinatorial approach. An example of solid phase combinatorial synthesis of a library of 37 compounds is reported.

Lipopolysaccharides (LPSs) constitute the lipid portion of the outer leaflet of Gram-negative bacteria; they are essential for growth, and are also responsible for the variety of biological effects associated with Gram-negative sepsis. Recent advances have elucidated the exact chemical structure of this highly complex macromolecule and part of the enzymology involved in its biosynthesis. Enzymes involved in LPS biogenesis are optimal targets for the development of novel therapeutics since they are sufficiently conserved among diverse, clinically-relevant bacteria and no analogue counterpart is present in humans. During the last thirty years a number of inhibitors to LPS biosynthesis have been developed: some of these compounds have antibacterial properties, while others show excellent in vitro activity and are undergoing further investigation. This review will focus on the biology of LPS in bacteria summarizing the knowledge about structure and enzymatic catalysis, as well as chemical efforts towards the synthesis of inhibitors of the key enzymes involved in the biosynthesis of the minimal conserved structure Kdo2-LipA, also referred to as Re LPS. Only a short overview will be given on lipid A biosynthesis and inhibitors, while main focus will be Kdo biosynthesis towards Re LPS. Future directions and perspectives will also be outlined. © 2008 Bentham Science Publishers Ltd.

7-Deoxy-uniflorine A (6), synthesized ex novo with a straightforward and simple strategy, and the analogues 4, 5 and 7, were evaluated as potential inhibitors of insect trehalase from Chironomus riparius and Spodoptera littoralis. All the compounds were tested against porcine trehalase as the mammalian counterpart and α-amylase from human saliva as a relevant glucolytic enzyme. The aim of this work is the identification of the simplest pyrrolizidine structure necessary to impart selective insect trehalase inhibition, in order to identify new specific inhibitors that can be easily synthesized compared to our previous reports with the potential to act as non-toxic insecticides and/or fungicides. All the derivatives 4–7 proved to be active (from low micromolar to high nanomolar range activity) towards insect trehalases, while no activity was observed against α-amylase. In particular, the natural compound uniflorine A and its 7-deoxy analogue were found to selectively inhibit insect trehalases, as they are inactive towards the mammalian enzyme. The effect of compound 6 was also analyzed in preliminary in vivo experiments. These new findings allow the identification of natural uniflorine A and its 7-deoxy analogue as the most promising inhibitors among a series of pyrrolizidine derivatives for future development in the agrochemical field, and the investigation also outlined the importance of the stereochemistry at C-6 of pyrrolizidine nucleus to confer such enzyme specificity.

Oligosaccharide processing enzymes such as glycosidases and glycosyltransferases are important classes of biocatalysts involved in synthesising specific oligosaccharide structures on proteins and lipids. These enzymes are known to be involved in a wide range of important biological processes, such as intestinal digestion, post-translational processing of glycoproteins, lysosomal catabolism of glycoconjugates and inter-cellular recognition events. Inhibition of these enzymes can disrupt biosynthesis of oligosaccharides, thus interfering in all of these processes. Hence, "glyco-enzyme" inhibitors might have enormous therapeutic potential in many diseases such as viral infection, cancer and diabetes. This very important prospect has led to increasing interest and demand for these compounds. Interference in oligosaccharide processing is the basis for the anti-influenza neuraminidase inhibitors that have recently been marketed and also for the potential use of glycosidase inhibitors against HIV, Gaucher's disease, hepatitis, and cancer. Since a rational design and synthesis of inhibitors are often extremely difficult due to the limited information regarding the structure of the active site, combinatorial approaches are particularly promising. This review will focus on synthetic efforts for the preparation of combinatorial libraries of glyco-enzyme inhibitors.

The synthesis of new dendrons and their immobilization on collagen patches via thiol − ene photoclick reaction, followed by chemoselective alkoxyamino − carbonyl conjugation to carbohydrates is presented. XPS, FTIR, and ELLA assays con fi rmed the e ff ectiveness of the collagen multivalent neoglycosylation

Structural requirements of d -arabinose 5-phosphate isomerase (KdsD, E.C. 5.3.1.13) from Pseudomonas aeruginosa were analysed in detail using advanced NMR techniques. We performed epitope mapping studies of the binding between the enzyme and the most potent KdsD inhibitors found to date, together with studies of a set of newly synthesised arabinose 5-phosphate (A5P) mimetics. We report here the first experimental evidence that KdsD may bind the furanose form of A5P, suggesting that catalysis of ring opening may be an important part of KdsD catalysis.

Despite the relevance of carbohydrates as cues in eliciting specific biological responses, the covalent surface modification of collagen-based matrices with small carbohydrate epitopes has been scarcely investigated. We report thereby the development of an efficient procedure for the chemoselective neoglycosylation of collagen matrices (patches) via a thiol-ene approach, between alkene-derived mono-saccharides and the thiol-functionalized material surface. Synchrotron radiation-induced X-ray photoelectron spectroscopy (SR-XPS), Fourier transform-infrared (FT-IR), and enzyme-linked lectin assay (ELLA) confirmed the effectiveness of the collagen neoglycosylation. Preliminary biological evaluation in osteoarthritic models is reported. The proposed methodology can be extended to any thiolated surface for the development of smart biomaterials for innovative approaches in regenerative medicine.

Osteogenic Growth Peptide (OGP) motifs were tethered to SULFHYDRYL-BIND(TM) polystyrene plates tuning spatial presentation of the different functional domains. The effects of the different surface-tethered OGP motifs have been evaluated in mesenchymal stem cells (MSCs) osteogenesis. A culture medium without any osteogenic supplements was used in order to evaluate the OGP effect, avoiding any interference by additional factors. The motif YGFGG resulted to be the most interesting, strongly enhancing the expression of BMP2 that plays a fundamental role in bone regeneration. With this study we present new evidence of the role of OGP in osteogenesis and new insights into different OGP motifs able to act as best ligands for the design of innovative bioactive materials for osteogenesis promotion and regenerative medicine applications.

A new approach for tethering of bioactive molecules via arginine is proposed and validated on collagen 2D matrices. The method involves the introduction of a methyl ketone on arginine side-chains, followed by reaction with model alkoxyamino derivatives. This journal is © the Partner Organisations 2014.

Stable C-glycosidic an analogues of 2-O-(beta-D-glucopyranosyl)-sn-glycerol (In), 2-O-(beta-D-galactopyranosyl)-sn glycerol (Ib), 1-O-(beta-D-glucopyranosyl)-sn-glycerol (7) and their dipalmitoyl ester have been synthesised starting from the corresponding 2,3,4,6-tetra-O-benzyl-glyconolactones 9. The 2-O-derivatives 1 were obtained by methylenation of the lactone 9, reaction of the obtained glycoexoenitol 10 with a malonyl radical, reduction of the malonyl derivative 11 and deprotection. The 1-O-derivative 7 was obtained by reaction of the lactone 9 with butenylmagnesium bromide, reduction of the obtained lactol 14, osmylation and deprotection. (C) 1997 Elsevier Science Ltd.

A small set of N-bridged 1-deoxynojirimycin dimers has been synthesized and evaluated as potential inhibitors of insect trehalase from midge larvae of Chironomus riparius , porcine trehalase as the mammalian counterpart and α-amylase from human saliva. All the tested compounds ( 2 – 4 ) proved to be active (micromolar range activity) against insect trehalase, showing selectivity toward the insect glycosidase. No activity was observed against α-amylase.

Hybrid organic-inorganic solids represent an important class of engineering materials, usually prepared by sol-gel processes by cross-reaction between organic and inorganic precur- sors. The choice of the two components and control of the reaction conditions (especially pH value) allow the synthe- sis of hybrid materials with novel prop- erties and functionalities. 3-Glycidoxy- propyltrimethoxysilane (GPTMS) is one of the most commonly used organ- ic silanes for hybrid-material fabrica- tion. Herein, the reactivity of GPTMS in water at different pH values (pH 2- 11) was deeply investigated for the first time by solution-state multinuclear NMR spectroscopic and mass spectro- metric analysis. The extent of the dif- ferent and competing reactions that take place as a function of the pH val- ue was elucidated. The NMR spectro- scopic and mass spectrometric data clearly indicate that the pH value de- termines the kinetics of epoxide hy- drolysis versus silicon condensation. Under slighly acidic conditions, the epoxy-ring hydrolysis is kinetically more favourable than the formation of the silica network. In contrast, under basic conditions, silicon condensation is the main reaction that takes place. Full characterisation of the formed inter- mediates was carried out by using NMR spectroscopic and mass spectro- metric analysis. These results indicate that strict control of the pH values allows tuning of the reactivity of the organic and inorganic moities, thus laying the foundations for the design and synthesis of sol-gel hybrid bioma- terials with tuneable properties.

Poly(-caprolactone), PCL, has been functionalized with a biologically relevant monosaccharide, i.e. glucosamine, in a single step process downstream to material fabrication. Glucosamine-functionalised PCL showed enhanced cell density and spreading then the non-functionalised samples

The synthesis of the disaccharides methyl 4-O-(2'/3'-O-sulfo-beta-D-glucopyranosyluronic acid)-2-amino-2-deoxy-alpha-D-glucopyranoside 3 and 4 as disodium salts is described. Allyl 4,6-O-benzylidene-alpha-D-glucopyranoside 6 was converted to trichloroacetimidate 20. Glycosylation of 20 with 5 promoted by BF3 . OEt(2) gave disaccharide 21. Deacetylation of 21 followed by monoacetylation of the resultant diol 22 afforded the two monoacetylated disaccharides 23 and 24. Sulfation and deprotection of each disaccharide gave the desired sulfated compounds 3 and 4.

11 páginas, 8 figuras, 4 tablas, 3 esquemas -- PAGS nros. 21-31, Magnetic Resonance Imaging (MRI) using paramagnetic systems as contrast agents is receiving increased attention as diagnostic tool in the clinic. At the same time, NMR of paramagnetic systems can also be applied in biochemical fields; for example, the use of Paramagnetic Relaxation Enhancement (PRE) allows structure refinement and the analysis of transient dynamic processes involved in macromolecular complex formation. Herein we report the synthesis and computational characterization of a new DOTA-like sialic acid conjugate, which can be used both in MRI and PRE applications when coordinated to a suitable paramagnetic metal, We gratefully acknowledge financial supports from the University of Milano-Bicocca (FAR2008) and computational facilities from CILEA (Consorzio Interuniversitario Lomabardo per l’Elaborazione Automatica), Programma Operativo Regione Lombardia Ob. 3 Fondo Sociale Europeo 2000–2006, Sovvenzione Globale Progetto Ingenio A0001127/2007 and Consorzio Interuniversitario Nazionale ‘Metodologie e Processi Innovativi di Sintesi’ (C.I.N.M.P.I.S.).

A small set of nojirimycin- and pyrrolidine-based iminosugar derivatives has been synthesized and evaluated as potential inhibitors of porcine and insect trehalases. Compounds 12, 13 and 20 proved to be active against both insect and porcine trehalases with selectivity towards the insect glycosidase, while compounds 10, 14 and 16 behaved as inhibitors only of insect trehalase. Despite the fact that the activity was found in the micromolar range, these findings may help in elucidating the structural features of this class of enzymes of different origin, which are still scarcely characterised.

Trehalose has been studied for more than a hundred of years, but its biochemical and physico-chemical properties are still far from being fully understood, despite the abundance of published data. A huge number of publications has recently appeared on trehalose functions and properties, and many rev...

Several glycoprocessing enzymes and glycoreceptors have been recognized as important targets for therapeutic intervention. This concept has inspired the development of important classes of therapeutics, such as anti-influenza drugs inhibiting influenza virus neuraminidase, anti-inflammatory drugs targeting lectin-sialyl-Lewis X interaction and glycosidase inhibitors against HIV, Gaucher’s disease, hepatitis and cancer. These therapeutics are mainly carbohydrate mimics in which proper modifications permit stronger interactions with the target protein, higher stability, better pharmacokinetic properties and easier synthesis. Furthermore, the conformational rigidity and polyfunctionality of carbohydrates stimulate their use as scaffolds for the generation of libraries by combinatorial decoration with different pharmacophores. This mini-review will present examples of how to exploit carbohydrates mimics and scaffolds in drug research.

Covering: 2000 to 2010 Kdo belongs to the 3-deoxysugar ‘family’ and is a critical monosaccharidic component of lipopolysaccharides (LPSs) in Gram-negative bacteria. The incorporation of Kdo into LPSs is a vital step in the assembly of the protective outer membrane of Gram-negative bacteria. This review intends to present recent advances on structural/biocatalytic knowledge on the four enzymes involved in Kdo metabolism, and on the synthesis and biological activity of analogues of biosynthetic intermediates, highlighting the potential of this pathway for the discovery of new antibacterials – a pressing need due to the emergence of new classes of antibiotic-resistant bacteria.

An efficient method for the direct and covalent decoration of granules of nanostructured apatite with a sample monosaccharide is presented: the hydroxyapatite material was directly functionalised with a short azido-containing spacer arm, to which alpha-propargyl glucopyranoside has been chemoselectively ligated by Huisgen-type cycloaddition. The 'glycosylated' hydroxypatite was characterised by its ability to interact with glucose recognising lectins. (C) 2011 Elsevier Ltd. All rights reserved.

Carbonated hydroxyapatite (CHA) has been successfully biodecorated with carbohydrate derivatives, via silylation of the hydroxy groups of the apatite and subsequent covalent bonding with a suitably functionalized carbohydrate moiety. The presented procedure opens the way toward covalent biofunctionalisation of CHA with carbohydrates. © Georg Thieme Verlag Stuttgart New York.

Lipopolysaccharide (LPS), which constitutes the lipid portion of the outer leaflet of Gram-negative bacteria, is essential for growth. It is also responsible for the variety of biological effects associated with Gram-negative sepsis. Recent advances have elucidated the exact chemical structure of this highly complex macromolecule and much of the enzymology involved in its biosynthesis. Enzymes involved in LPS biogenesis are optimal targets for the development of novel therapeutics since they are sufficiently conserved among diverse, clinically-relevant bacteria and no analogue counterpart is present in humans. During the last thirty years a number of inhibitors of LPS biosynthesis have been developed: some of these compounds have antibacterial properties, while others show excellent in vitro activity and are undergoing further investigation. The main focus of this review will be the biology of LPS in bacteria summarizing the knowledge about structure and enzymatic catalysis, as well as chemical efforts towards the synthesis of inhibitors of the key enzymes involved in the biosynthesis of Kdo, toward the minimal conserve structure Kdo2-LipA. In addition, very recent advances in deciphering the molecular mechanisms of LPS transport to the cell surface, as a new target to develop novel antibacterials, will be reported. Future directions and perspectives will also be outlined. © 2011 Bentham Science Publishers Ltd.

The identification and characterisation of Pseudomonas aeruginosa KdsD (Pa-KdsD), a D-arabinose-5P isomerase involved in the biosynthesis of 3-deoxy-D-manno-oct-2-ulosonic acid and thus of lipopolysaccharide (LPS), are reported. We have demonstrated that KdsD is essential for P. aeruginosa survival and thus represents a key target for the development of novel antibacterial drugs. The key amino acid residues for protein activity have been identified. The structural requirements for substrate recognition and binding have been characterised for the wild-type protein, and the effect of mutations of the key residues on catalytic activity and binding have been evaluated by saturation transfer difference (STD) NMR spectroscopy. Our data provide important structural information for the rational design of new KdsD inhibitors as potential antibacterial drugs. Rational design of antibacterial drugs: The identification and characterisation of P. aeruginosa API, which is involved in the biosynthesis of lipopolysaccharides, are reported. Structural requirements for substrate recognition and binding and the effects of mutations of the key residues have been evaluated by STD NMR spectroscopy. This information is essential for the rational design of new potential antibacterial drugs. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Carbohydrate chemistry and glycobiology have become a "hot" subject. These extensive, complex structures serve essential roles in cell surface phenomena, but we are only beginning to understand what some of these functions are; any advances in the development of synthetic and/or analytical tools for glycobiology are extremely useful for our understanding of the roles of carbohydrates in biology, and as biomarkers of physiological/pathological states. This review provides an outlook of the potential of carbohydrate chemistry/ biology in magnetic resonance imaging (MRI), a major important and prominent technique in diagnostic clinical medicine and biomedical research. During the last 30 years, MRI has developed from an intriguing research project to an essential diagnostic method in the clinic. Although MRI contrast in endogenous tissues provides excellent sensitivity for detecting subtle changes in anatomy and function, MRI still has poor specificity for attributing image contrast to specific biological processes. To overcome this limitation, MRI methods are being developed that induce changes in MR image contrast in response to molecular compositions and functions that serve as early biomarkers of pathologies. Carbohydrates with their intriguing chemistry, not only can provide structures for novel MRI probes for imaging specific biological processes, but can themselves provide novel targets/biomarkers. For example, the glycan structure can simply provide a molecular scaffold for modulating the physicochemical properties of the imaging contrast agent, or can be used for the design of novel MR agents with the ability to disclose relevant physiological or pathological cellular events. © 2011 Bentham Science Publishers Ltd.

In this study ultrasound has been utilised for the Fischer glycosylation using free sugars and sulphuric acid immobilized on silica as catalyst. N-acetyl-d-glucosamine, N-acetyl-d-galactosamine, d-glucose, d-galactose, d-mannose, l-fucose, and lactose were glycosylated with propargyl alcohol or 2-azidoethanol affording the corresponding glycosides, with the production of the α-glycopyranoside as the dominant product. Remarkable acceleration of the glycosylation reactions (15 min-2h compared to several hours) over reported procedures together with good yields were always observed. © Springer Science+Business Media B.V. 2010.

Compounds that bind in the minor groove of DNA have found use in the experimental treatment of cancer and certain infectious diseases. Furthermore, agents which target and can recognize discrete sequences of DNA have the potential to offer selective therapies by modulating the activity of specific transcription factors or genes. For this reason, a number of sequence-selective DNA binding agents have been evaluated with a range of affinities and recognition fidelities. In this respect, the pyrrolo[2,1-c][1,4]benzodiazepines (PBDs) are of interest as they bind to guanine residues in the minor groove with a preference for Pu-G-Pu sequences. A dramatic increase in cytotoxicity and sequence selectivity has been achieved by linking two PBD units to form PBD dimers as cross-linking agents on opposite DNA strands (e.g., interstrand cross-links). SJG-136 is currently undergoing Phase I evaluation in both the United States (through the NCI) and United Kingdom (through Cancer Research United Kingdom). This review will focus on design, synthesis and structure activity relationship studies of pyrrolobenzodiazepines as anticancer therapeutics reported since 2003.