A Branched and Double Alpha-Gal-Bearing Synthetic Neoglycoprotein as a Biomarker for Chagas Disease

Chagas disease (CD) is caused by the parasite Trypanosoma cruzi and affects 6–7 million people worldwide. The diagnosis is still challenging, due to extensive parasite diversity encompassing seven genotypes (TcI-VI and Tcbat) with diverse ecoepidemiological, biological, and pathological traits. Chemotherapeutic intervention is usually effective but associated with severe adverse events. The development of safer, more effective therapies is hampered by the lack of biomarker(s) (BMKs) for the early assessment of therapeutic outcomes. The mammal-dwelling trypomastigote parasite stage expresses glycosylphosphatidylinositol-anchored mucins (tGPI-MUC), whose O-glycans are mostly branched with terminal, nonreducing α-galactopyranosyl (α-Gal) glycotopes. These are absent in humans, and thus highly immunogenic and inducers of specific CD anti-α-Gal antibodies. In search for α-Gal-based BMKs, here we describe the synthesis of neoglycoprotein NGP11b, comprised of a carrier protein decorated with the branched trisaccharide Galα(1,2)[Galα(1,6)]Galβ. By chemiluminescent immunoassay using sera/plasma from chronic CD (CCD) patients from Venezuela and Mexico and healthy controls, NGP11b exhibited sensitivity and specificity similar to that of tGPI-MUC from genotype TcI, predominant in those countries. Preliminary evaluation of CCD patients subjected to chemotherapy showed a significant reduction in anti-α-Gal antibody reactivity to NGP11b. Our data indicated that NGP11b is a potential BMK for diagnosis and treatment assessment in CCD patients.     

Antifungal Activity of Mexican Propolis on Clinical Isolates of Candida Species

Infections caused by micro-organisms of the genus Candida are becoming a growing health problem worldwide. These fungi are opportunistic commensals that can produce infections—clinically known as candidiasis—in immunocompromised individuals. The indiscriminate use of different anti-fungal treatments has triggered the resistance of Candida species to currently used therapies. In this sense, propolis has been shown to have potent antimicrobial properties and thus can be used as an approach for the inhibition of Candida species. Therefore, this work aims to evaluate the anti-Candida effects of a propolis extract obtained from the north of Mexico on clinical isolates of Candida species. Candida species were specifically identified from oral lesions, and both the qualitative and quantitative anti-Candida effects of the Mexican propolis were evaluated, as well as its inhibitory effect on C. albicans isolate’s germ tube growth and chemical composition. Three Candida species were identified, and our results indicated that the inhibition halos of the propolis ranged from 7.6 to 21.43 mm, while that of the MFC and FC₅₀ ranged from 0.312 to 1.25 and 0.014 to 0.244 mg/mL, respectively. Moreover, the propolis was found to inhibit germ tube formation (IC₅₀ ranging from 0.030 to 1.291 mg/mL). Chemical composition analysis indicated the presence of flavonoids, including pinocembrin, baicalein, pinobanksin chalcone, rhamnetin, and biochanin A, in the Mexican propolis extract. In summary, our work shows that Mexican propolis presents significant anti-Candida effects related to its chemical composition, and also inhibits germ tube growth. Other Candida species virulence factors should be investigated in future research in order to determine the mechanisms associated with antifungal effects against them.     

Open-framework copper adeninate compounds with three-dimensional microchannels tailored by aliphatic monocarboxylic acids

A series of isostructural copper(II) coordination polymers containing the nucleobase adenine and different monocarboxylic acids as bridging ligands, [Cu(2)(μ(3)-ade)(2)(μ(2)-OOC(CH(2))(n)CH(3))(2)]·xH(2)O (n from 0 to 5), have been prepared. Single-crystal X-ray analysis of acetate (n = 0) and butanoate (n = 2) compounds shows a covalent three-dimensional network in which the copper(II) centers are bridged by μ-N3,N7,N9-adeninato and μ-O,O'-carboxylato ligands, with crystallization water molecules trapped in the pores, which are decorated by the Watson-Crick faces of the adenine. The tunable permanent porosity of guest-free compounds was confirmed by gas adsorption measurements.     

Cocondensation reactions of heterocyclic aromatic compounds with lithium, calcium and magnesium atoms at 77 K

Calcium and magnesium atoms were cocondensed with aromatic heterocycles containing five- and six-membered rings in the presence of THF at 77 K. In the case of calcium the cocondensation with five-membered heterocyclic compounds resulted in C-H bond activations and led to the corresponding aryl calcium compounds, while magnesium did not show comparable reactions. When six-membered heterocyclic compounds, e.g., pyridine and 4-methylpyridine (4-picoline) were cocondensed with calcium, magnesium and lithium atoms, all reactions led to the formation of non-metallated aromatic products and the formation of metal hydride. DFT calculations at the B3LYP/6-31G** level of theory were carried out in order to interpret the pathways of the cocondensation reactions using calcium atoms and identify the possible intermediates involved. In all reactions π- and σ-complexes between calcium atoms and the heterocyclic aromatic reactant were found as stable intermediates on the energy hypersurface.     

Stereospecific 5JHortho,OMe couplings in methoxyindoles,methoxycoumarins, and methoxyflavones

Long‐range coupling constants ⁵J_Hortho,OMe were measured in series of methoxyindoles, methoxycoumarins, and methoxyflavones by the modified J doubling in the frequency domain method. The COSY and NOESY spectra revealed the coupling of the –OMe group with a specific proton at the ortho position and its preferred conformation. Homonuclear ¹H–¹H couplings were confirmed by irradiation of the –OMe signal. Density functional theory calculations of ⁵J_Hortho,OMe using the modified aug‐cc‐pVTZ basis set evidenced that the Fermi contact term shows good agreement with the experimental J values. Accurate chemical shift and coupling constant values followed after iterative quantum mechanical spectral analysis using the PERCH software. Copyright © 2014 John Wiley & Sons, Ltd.     

Efficient Palladium‐Catalyzed Aminocarbonylation of Aryl Iodides Using Palladium Nanoparticles Dispersed on Siliceous Mesocellular Foam

A highly dispersed nanopalladium catalyst supported on mesocellular foam (MCF), was successfully used in the heterogeneous catalysis of aminocarbonylation reactions. During the preliminary evaluation of this catalyst it was discovered that the supported palladium nanoparticles exhibited a “release and catch” effect, meaning that a minor amount of the heterogeneous palladium became soluble and catalyzed the reaction, after which it re‐deposited onto the support.     

Saccharification of native sugar cane bagasse pith by the cross-synergistic action of cellulases fromPenicillium sp. CH-M-001 andA. terreus CH-M-013

Applied Biochemistry and Biotechnology - Filter paper, carboxymethylcellulase, β-glucosidase, and xylanase activities were determined and compared to cellulases originating fromAureobasidium...