Two crystalline pentofuranosyl bromides: tri-O-(p-nitrobenzoyl)-β-D-ribofuranosyl bromide and tri-O-(p-nitrobenzoyl)-α,β-D-xylofuranosyl bromide

Methyl α,β-D-ribofuranoside was p-nitrobenzoylated to give methyl tri-O-(p-nitrobenzoyl)-β-D-ribofuranoside (2),and this was treated with HBr in acetic acid to give tri- O-(p-nitrobenzoyl)-β-D-ribofuranosyl bromide (3). Bromide 3 could be converted into 2,5-anhydro-3,4,6-tri-O-(p-nitrobenzoyl)-D-allononitrile (4) with Hg(CN)₂, or hydrolyzed to 2,3,5-tri-O-(p-nitrobenzoyl)-D-ribose (5). On p-nitro- benzoylation, 5 gave tetra-O-(p-nitrobenzoyl)-β-D-ribofuranose (6). The synthesis of tri-O-(p-nitrobenzoyl)-α-β-D-xylofuranosyl bromide (11) started with methyl 3,5-O-isopropylidene-β-D-xyldfuranoside (7), which was p-nitrobenzoylated to give ester 8; this was then hydrolyzed, and the product p-nitrobenzoylated to give methyl tri-O-(p-nitrobenzoyl)-β-D-xylofuranoside (10) which, on treatment with HBr in CH₂Cl₂, afforded the desired bromide (11). Nucleophilic replacement with Hg(CN)₂ afforded 2,5-anhydro-3,4,6-tri-O-(p-nitrobenzoyl)-D-gulononitrile (12).     

Synthesis and characterization of pure cubic zirconium oxide nanocrystals by decomposition of bis-aqua, tris-acetylacetonato zirconium(IV) nitrate as new precursor complex

Pure zirconium oxide (ZrO₂) nanocrystals with diameters 10-30 nm are fabricated from bis-aqua, tris-acetylacetonato zirconium(IV) nitrate; [Zr(acac)₃(H₂O)₂](NO₃); by thermal decomposition. The different combinations of oleylamine, or polyethyleneglycol (PEG) and triphenylphosphine, were added as surfactants to control the particle size. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet-visible (UV-Vis) spectroscopy, photoluminescence spectroscopy (PL), Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS) to depict the phase and morphology. The synthesized ZrO₂ nanoparticles have a cubic structure. The FT-IR spectrum showed the purity of obtained ZrO₂ nanocrystals with cubic phase. The UV-Visible absorption peak for ZrO₂ was observed at 233 nm (5.3 eV in photon energy). The band at 363 nm for cubic ZrO₂ nanocrystals was found.     

Functional and structural alterations induced by copper in xanthine oxidase

Xanthine oxidase （XO）, a key enzyme in purine metabolism, produces reactive oxygen species causing vascular injuries and chronic heart failure. Here, copper＇s ability to alter XO activity and structure was investigated in vitro after pre-incubation of the enzyme with increasing Cue＋ concentrations for various periods of time. The enzymatic activity was measured by following XO-catalyzed xanthine oxidation to uric acid under steady-state kinetics conditions. Structural alterations were assessed by electronic absorption, fluorescence, and circular dichroism spectroscopy. Results showed that Cu^2＋ either stimulated or inhibited XO activity, depending on metal concentration and preincubation length, the latter also determining the inhibition type. Cu^2＋-xo complex formation was characterized by modifications in XO electronic absorption bands, intrinsic fluorescence, and α-helical and β-sheet content. Apparent dissociation constant values implied high- and low-affinity Cu^2＋ binding sites in the vicinity of the enzyme＇s reactive centers. Data indicated that Cu^2＋ binding to high-affinity sites caused alterations around XO molybdenum and flavin adenine dinucleotide centers, changes in secondary structure, and moderate activity inhibition; binding to low affinity sites caused alterations around all XO reactive centers including FeS, changes in tertiary structure as reflected by alterations in spectral properties, and drastic activity inhibition. Stimulation was attributed to transient stabilization of XO optimal conformation. Results also emphasized the potential role of copper in the regulation of XO activity stemming from its binding properties.     

3-deoxy-2,5-DI-O-p-nitrobenzoyl-α-D-threo-pentofuranosyl bromide,a starting material for the synthesis of nucleosides

Hydrogenation (Raney nickel) of methyl 2,3-anhydro-α- and β-D-lyxo-furanoside (3 and 12) for 12 h at $\text{60}\text{60}$ lb.in.-2 afforded methyl 3-deoxy-α- and β-D-threo pentofuranoside (4 and 13). These were p-nitrobenzoylated to give the 2,5-di-p-nitrobenzoates (5b and 14b) which, on treatment with hydrogen bromide in acetyl bromide—acetic acid—dichloromethane, afforded the title compound (6b). The structure of compound 4 was established by conversion into the previously prepared 2,5-dibenzoate 5a of known structure, and the anomeric configuration of 6b was established by comparison of its optical rotation and the signals of its anomeric proton with those of methyl 3-deoxy-D-threo-pentofuranosides.     

Stoichiometry of the oligomycin-sensitivity-conferring protein (OSCP) in the mitochondrial F0F1-ATPase determined by an immunoelectrotransfer blot technique

The ratio between the amount of oligomycin-sensitivity-conferring protein (OSCP) and the amount of the and β subunits of F₁-ATPase in the mitochondria has been determined by a method combining electrophoresis, electrotransfer and immunotitration with monoclonal antibodies. The peptides separated in SDS-polyacrylamide gel electrophoresis were blotted to nitrocellulose sheets by electrotransfer. The nitrocellulose sheets were incubated with ¹²⁵I-labelled purified monoclonal antibodies specific to various peptides. The ¹²⁵I-labelled immune complexes were located by immunodecoration using peroxidase-conjugated second antibodies and the blotted peptides were revealed with H₂O₂ and -naphthol. The amount of immune complex present on the nitrocellulose was determined by counting the radioactivity present on the spots. The amount of peptide blotted is directly proportional to the amount of protein loaded on the electrophoresis. By comparing standard curves made with the isolated proteins to the values obtained in the presence of various amounts of the membrane-protein complex, one can calculate the content of this peptide in the membrane. It was found that the mitochondrial membrane contains 2 mol of OSCP per mol of F₁.     

Evaluation of the Effect of Vitamin D Supplementation on Anthropometric Indicators and Dietary Intake of Patients with Type 2 Diabetes

Background:Various studies have shown that diabetes and its complications are associated with vitamin D deficiency. Due to the possible role of vitamin D in reducing the complications of diabetes and the high prevalence of its deficiency in Iran, this study was designed to investigate the effect of vitamin D supplementation on anthropometric indices and dietary intake of patients with type 2 diabetes.Methods:This randomized clinical trial (RCT) study was performed on 74 patients with type 2 diabetes (T2DM). Patients randomly divided into two groups to receive vitamin D (VD) supplementation (100 μg or 4000 IU/day) or placebo for three months, randomization was based on the permutated-block method. Anthropometric indices including body weight (BW), body mass index (BMI) and waist circumference (WC) and physical activity, dietary intake were assessed by validated methods at the beginning and end of the trial.Results:VD supplementation had not any significant differences in anthropometric indices, dietary intake and physical activity between the two groups.Conclusion:Finally, it can be concluded, receiving 100 micrograms/day of VD for three months had no favourable effects on patients with T2DM.Key Words: Anthropometric indices, Diabetes Mellitus, Dietary intake, Vitamin D     

The bone microenvironment increases phenotypic plasticity of ER+ breast cancer cells

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Trichome micromorphology in Alcea L. and allied genera (Malvaceae) and its systematic implication

Trichomes of 26 species of Alcea (Malvaceae) were investigated using light (LM) and scanning electron microscopy (SEM). The trichomes show a great micromorphological variation, which provides data useful for species delimitation in Alcea. Two basic types of trichomes could be distinguished in Alcea and allied genera: glandular and eglandular. The glandular trichomes could in turn be subdivided into two subtypes: capitate and clavate. The eglandular trichomes could be subdivided into five subtypes: simple, fascicled, stellate, fascicled-stellate and pluri-radiate. Characters of taxonomic interest are: trichome density (glabrous to dense), number of arms per trichome, orientation relative to the epidermal surface (appressed to erect) and presence/absence of a stalk. According to the results the species of Alcea can be divided into four informal groups based on trichome types. The results further support the exclusion of the annual Althaea species from the perennial ones and their close relationship to Malva. In addition, a close relationship between perennial Althaea and basal Alcea lineages is supported. Based on the evolutionary framework provided by recent molecular phylogenetic investigations, the following trends can be observed in the Malva alliance: long and narrow-armed trichomes are primitive in relation to short and thick-armed trichomes; dense indumentum coverage is primitive in relation to moderately dense or glabrous ones; presence of simple hairs on stem (particularly on leaves) is more advanced than their absence; spreading villous-stellate and fascicled trichomes are more advanced than appressed stellate ones. Clavate trichomes, which were found exclusively in a few species of Alcea, should be considered as a derived state in relation to capitate ones, and they may provide a synapomorphy for the crown group of Alcea.     

ABCC6P1 pseudogene induces ABCC6 upregulation and multidrug resistance in breast cancer

Molecular Biology Reports - The elevated drug efflux by ABC transports has been considered the primary mechanism of drug resistance in cancer. Recently, non-coding RNAs, such as pseudogenes, have...