Pollution from organic molecules is a major environmental issue that needs to be addressed because of the negative impacts of both the harmfulness of the molecule structures and the toxicity that can spread through natural media. This is mainly due to their unavoidable partial oxidation under exposure to air and solar radiation into diverse derivatives. Even when insoluble, the latter can be dispersed in aqueous media through solvatation and/or complexation with soluble species.
View Article and Find Full Text PDFConjugation of carbohydrates to nanomaterials has been extensively studied and recognized as an alternative in the biomedical field. Dendrimers synthesized with mannose at the end group and with entrapped zero-valent copper/silver could be a potential candidate against bacterial proliferation. This study is aimed at investigating the bactericidal activity of metal-glycodendrimers.
View Article and Find Full Text PDFAberrant glycosylation patterns of glycoproteins and glycolipids have long been recognized as one the major hallmarks of cancer cells that has led to numerous glycoconjugate vaccine attempts. These abnormal glycosylation profiles mostly originate from the lack of key glycosyltransferases activities, mutations, over expressions, or modifications of the requisite chaperone for functional folding. Due to their relative structural simplicity, -linked glycans of the altered mucin family of glycoproteins have been particularly attractive in the design of tumor associated carbohydrate-based vaccines.
View Article and Find Full Text PDFZeolite NaP1 was found to display the highest affinity for CO in preliminary modifications of coal fly ash-derived zeolites (4A, Y, NaP1 and X) by four amines (1,3-diaminopropane, ,,','-tetramethylethylenediamine, Tris(2-aminoethyl)amine and ethylenediamine). In the second step, different fatty acid loaded NaP1 samples were prepared using palmitic, oleic and lauric acids. CO and HO thermal programmed desorption (TPD) revealed changes in intrinsic basicity and hydrophilic character, expressed in terms of CO and HO retention capacity (CRC and WRC, respectively).
View Article and Find Full Text PDFThis paper consists of a deep analysis and data comparison of the main strategies undertaken for achieving truly reversible capture of carbon dioxide involving optimized gas uptakes while affording weakest retention strength. So far, most strategies failed because the estimated amount of CO produced by equivalent energy was higher than that captured. A more viable and sustainable approach in the present context of a persistent fossil fuel-dependent economy should be based on a judicious compromise between effective CO capture with lowest energy for adsorbent regeneration.
View Article and Find Full Text PDFGalectins, a family of endogenous glycan-binding proteins, play crucial roles in a broad range of physiological and pathological processes. Galectin-1 (Gal-1), a proto-type member of this family, is overexpressed in several cancers and plays critical roles in tumor-immune escape, angiogenesis and metastasis. Thus, generation of high-affinity Gal-1 inhibitors emerges as an attractive therapeutic approach for a wide range of neoplastic conditions.
View Article and Find Full Text PDFMany traditional cancer treatments such as radiation and chemotherapy are known to induce cellular DNA damage as part of their cytotoxic activity. The cGAS-STING signaling axis, a key member of the DNA damage response that acts as a sensor of foreign or aberrant cytosolic DNA, is helping to rationalize the DNA-damaging activity of these treatments and their emerging immunostimulatory capacity. Moreover, cGAS-STING, which is attracting considerable attention for its ability to promote antitumor immune responses, may fundamentally be able to address many of the barriers limiting the success of cancer immunotherapy strategies, including the immunosuppressive tumor microenvironment.
View Article and Find Full Text PDFCatalytic ozonation for the total mineralization of bisphenol-A (BPA) from aqueous solution was investigated in the presence of various silica-based catalysts such as mesoporous silica, acid-activated bentonite (HMt) and montmorillonite-rich materials (Mt) ion-exchanged with Na and Fe cations (NaMt and Fe(II)Mt). The effects of the catalyst surface were studied by correlating the hydrophilic character and catalyst dispersion in the aqueous media to the silica content and BPA conversion. To the best of our knowledge, this approach has barely been tackled so far.
View Article and Find Full Text PDFThis review highlights the recent development in the use of carriers of increasing simplicities and versatile chemical ligation processes leading to synthetic vaccine candidates against tumor-associated carbohydrate antigens (TACAs). After briefly covering their structures, functions, occurrence, and biosynthesis, an overview of common conjugation chemistry is described with an emphasis on the versatile alkenyl glycosides as starting materials toward glycoconjugate syntheses. This is followed by a successive description of the numerous scaffolds and carriers used to progressively improve and simplify glycovaccine formulations.
View Article and Find Full Text PDFSelective antiadhesion antagonists of Uropathogenic (UPEC) type-1 Fimbrial adhesin (FimH) are attractive alternatives for antibiotic therapies and prophylaxes against acute or recurrent urinary tract infections (UTIs) caused by UPECs. A rational small library of FimH antagonists based on previously described -linked allyl α-D-mannopyranoside was synthesized using Heck cross-coupling reaction using a series of iodoaryl derivatives. This work reports two new members of FimH antagonist amongst the above family with sub nanomolar affinity.
View Article and Find Full Text PDFGalectins constitute a family of galactose-binding lectins overly expressed in the tumor microenvironment as well as in innate and adaptive immune cells, in inflammatory diseases. Lactose ((β-D-galactopyranosyl)-(1→4)-β-D-glucopyranose, Lac) and -Acetyllactosamine (2-acetamido-2-deoxy-4--β-D-galactopyranosyl-D-glucopyranose, LacNAc) have been widely exploited as ligands for a wide range of galectins, sometimes with modest selectivity. Even though several chemical modifications at single positions of the sugar rings have been applied to these ligands, very few examples combined the simultaneous modifications at key positions known to increase both affinity and selectivity.
View Article and Find Full Text PDFPerhaps the greatest limitation for the continually advancing developments in cancer immunotherapy remains the immunosuppressive tumor microenvironment (TME). The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) axis is an emerging immunotherapy target, with the resulting type I interferons and transcription factors acting at several levels in both tumor and immune cells for the generation of adaptive T cell responses. The cGAS-STING axis activation by therapeutic agents that induce DNA damage, such as certain chemotherapies, continues to be reported, highlighting the importance of the interplay of this signaling pathway and the DNA damage response in cancer immunity/immunotherapy.
View Article and Find Full Text PDFLabel-free detection of pathogens is of major concern to the microbiologist community. Most procedures require several steps and amplification techniques. Carbohydrates are well-established receptors for host-pathogen interactions, which can be amplified using glycodendritic architectures on the basis of multivalent binding interactions.
View Article and Find Full Text PDFGlycosylated NPs, including liposomes, are known to target various receptors involved in cellular carbohydrate transport, of which the mannoside binding receptors are attracting particular attention for their expression on various immune cells, cancers, and cells involved in maintaining central nervous system (CNS) integrity. As part of our interest in NP drug delivery, mannosylated glycoliposomal delivery systems formed from the self-assembly of amphiphilic neoglycolipids were developed, with a C-alkyl mannopyranoside (ML-C) being identified as a lead compoundcapable of entrapping, protecting, and improving the delivery of structurally diverse payloads. However, ML-C was not without limitations in both the synthesis of the glycolipids, and the physicochemical properties of the resulting glycoliposomes.
View Article and Find Full Text PDFAn unprecedented route for mitigating the inhibitory effect of lactic acid (LA) on milk fermentation was achieved through lactate adsorption on hydrotalcite (Ht) from simulated lactate extracts. During its regeneration by ozonation, Ht displayed catalytic activity that appeared to increase by addition of montmorillonite (Mt). Changes in the pH, Zeta potential and catalyst particle size during LA ozonation were found to strongly influence LA-LA, LA-catalyst and catalyst-catalyst interactions.
View Article and Find Full Text PDFThe trisaccharide, prop-2-ynyl 5-acetamido-3,5-dideoxy-d-glycero-α-d-galacto-2-nonulopyranosylonic acid-(2 → 3)-β-d-galactopyranosyl-(1 → 4)-2-acetamido-2-deoxy-β-d-glucopyranoside (9) has been efficiently synthesized in a few steps without the need of conformationally constrained glycosyl donors and acceptors or enzymes. First, using the known prop-2-ynyl 2-acetamido-2-deoxy-6-O-tert-butyldiphenylsilyl-β-d-glucopyranoside as acceptor (2) and the peracetylated galactosyl trichloroacetimidate (3) as glycosyl donor, followed by protecting groups manipulation, prop-2-ynyl (6-O-tert-butyldiphenylsilyl-β-d-galactopyranosyl)-(1 → 4)-2-acetamido-2-deoxy-6-O-tert-butyldiphenylsilyl-β-d-glucopyranoside (6) was synthesized with exclusive O-4 regioselectivity due to steric hindrance of the upper face of the acceptor at O-3. Sialylation with the thiophenyl glycosyl donor (7) afforded the desired trisaccharide with the shortest number of steps and in higher overall yield than previously reported methodologies.
View Article and Find Full Text PDFA code is defined by the nature of the symbols, which are used to generate information-storing combinations (e. g. oligo- and polymers).
View Article and Find Full Text PDFPeptide therapeutics offer numerous advantages in the treatment of diseases and disorders of the central nervous system (CNS). However, they are not without limitations, especially in terms of their pharmacokinetics where their metabolic lability and low blood-brain barrier penetration hinder their application. Targeted nanoparticle delivery systems are being tapped for their ability to improve the delivery of therapeutics into the brain non-invasively.
View Article and Find Full Text PDFThis brief review highlights systematic progress in the design of synthetic glycolipid (neoglycolipids) analogs evolving from the conventional architectures of natural glycosphingolipids and gangliosides. Given that naturally occurring glycolipids are composed of only one hydrophilic sugar head-group and two hydrophobic lipid tails embedded in the lipid bilayers of the cell membranes, they usually require extraneous lipids (phosphatidylcholine, cholesterol) to confer their stability. In order to obviate the necessity for these additional stabilizing ingredients, recent investigations have merged dendrimer chemistry with that of neoglycolipid syntheses.
View Article and Find Full Text PDFCancer treatment remains unsatisfactory with high rates of recurrence and metastasis. Immunomodulatory agents capable of promoting cellular antitumor immunity while inhibiting the local immunosuppressive tumor microenvironment could greatly improve cancer treatment. We have developed a multi-targeted mannosylated cationic liposome delivery system containing muramyl dipeptide (DS) and low doses of the chemotherapeutic agent cytarabine (Ara-C).
View Article and Find Full Text PDFGlycodendrimers have attracted considerable interest in the field of dendrimer sciences owing to their plethora of implications in biomedical applications. This is primarily due to the fact that cell surfaces expose a wide range of highly diversified glycan architectures varying by the nature of the sugars, their number, and their natural multiantennary structures. This particular situation has led to cancer cell metastasis, pathogen recognition and adhesion, and immune cell communications that are implicated in vaccine development.
View Article and Find Full Text PDFGlycoconjugates are involved in several pathological processes. Glycomimetics that can favorably emulate complex carbohydrate structures, while competing with natural ligands as inhibitors, are gaining considerable attention owing to their improved hydrolytic stability, binding affinity, and pharmacokinetic (PK) properties. Of particular interest are the families of α-d-mannopyranoside analogs, which can be used as inhibitors against adherent invasive Escherichia coli infections.
View Article and Find Full Text PDFBackground Chronic vascular disease atherosclerosis starts with an uptake of atherogenic modified low-density lipoproteins (LDLs) by resident macrophages, resulting in formation of arterial fatty streaks and eventually atheromatous plaques. Increased plasma sialic acid levels, increased neuraminidase activity, and reduced sialic acid LDL content have been previously associated with atherosclerosis and coronary artery disease in human patients, but the mechanism underlying this association has not been explored. Methods and Results We tested the hypothesis that neuraminidases contribute to development of atherosclerosis by removing sialic acid residues from glycan chains of the LDL glycoprotein and glycolipids.
View Article and Find Full Text PDFVanillin-based lactoside derivatives were synthetized using phase-transfer catalyzed reactions from per--acetylated lactosyl bromide. The aldehyde group of the vanillin moiety was then modified to generate a series of related analogs having variable functionalities in the position of the aromatic residue. The corresponding unprotected lactosides, obtained by Zemplén transesterification, were regioselectively 3'--sulfated using tin chemistry activation followed by treatment with sulfur trioxide-trimethylamine complex (MenN-SO).
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