Carnosine influences transcription via epigenetic regulation as demonstrated by enhanced histone acetylation of the pyruvate dehydrogenase kinase 4 promoter in glioblastoma cells.

Carnosine (ß-alanyl-L-histidine) affects a plethora of signaling pathways and genes in different biological systems. Although known as a radical scavenger, not all of these effects can simply be ascribed to its chemical nature. As previous experiments pointed towards the possibility that carnosine affects epigenetic regulation via histone acetylation, we investigated this hypothesis using the glioblastoma cell lines U87 and T98G in which carnosine's anti-neoplastic effect is accompanied by increased expression of pyruvate dehydrogenase kinase 4. Viability and expression of PDK4 was analyzed after incubation in carnosine and different histone deacetylase inhibitors (HDACi) using cell-based assays and qRT-PCR. In addition, chromatin immunoprecipitation (ChIP) experiments were performed and the global influence of carnosine on histone H3 acetylation was analyzed by Western blot. Carnosine as well as the HDACi used increased expression of PDK4. In addition, all compounds reduced cell viability, although differences were observed with regard to magnitude and required concentrations. ChIP analysis revealed increased acetylation of histone H3 in the PDK4 promoter of U87 and T98G cells (~ 1.3- and ~ 1.7-fold, respectively) 6 h after the addition of carnosine (50 mM) followed by increased expression of PDK4 mRNA. Western blots did not detect a general increase of H3 acetylation at a genome-wide scale under the influence of carnosine. Our experiments for the first time demonstrate that carnosine influences epigenetic regulation via increased histone acetylation.

Lanthanide coordination polymers with tetrafluoroterephthalate as a bridging ligand: thermal and optical properties.

By slow diffusion of triethylamine into a solution of 2,3,5,6-tetrafluoroterephthalic acid (H2tfBDC) and the respective lanthanide salt in EtOH/DMF single crystals of seven nonporous coordination polymers, (∞)(2)[Ln(tfBDC)(NO(3))(DMF)(2)]·DMF (Ln(3+) = Ce, Pr, Nd, Sm, Dy, Er, Yb; C2/c, Z = 8) have been obtained. In the crystal structures, two-dimensional square grids are found, which are composed of binuclear lanthanide nodes connected by tfBDC(2-) as a linking ligand. The coordination sphere of each lanthanide cation is completed by a nitrate anion and two DMF molecules (CN = 9). This crystal structure is unprecedented in the crystal chemistry of coordination polymers based on nonfluorinated terephthalate (BDC(2-)) as a bridging ligand; as for tfBDC(2-), a nonplanar conformation of the ligand is energetically more favorable, whereas for BDC(2-), a planar conformation is preferred. Differential thermal analysis/thermogravimetric analysis (DTA/TGA) investigations reveal that the noncoordinating DMF molecule is released first at temperatures of 100-200 °C. Subsequent endothermal weight losses correspond to the release of the coordinating DMF molecules. Between 350 and 400 °C, a strong exothermal weight loss is found, which is probably due to a decomposition of the tfBDC(2-) ligand. The residues could not be identified. The emission spectra of the (∞)(2)[Ln(tfBDC)(NO(3))(DMF)(2)]·DMF compounds reveal intense emission in the visible region of light for Pr, Sm, and Dy with colors from orange, orange-red, to warm white.

Optimized synthesis of tetrafluoroterephthalic acid: a versatile linking ligand for the construction of new coordination polymers and metal-organic frameworks.

Pure 2,3,5,6-tetrafluoroterephthalic acid (H(2)tfBDC) is obtained in high yields (95%) by reacting 1,2,4,5-tetrafluorobenzene with a surplus (>2 equiv) of n-butyllithium in tetrahydrofuran (THF) and subsequent carbonation with CO(2) without any extensive purification procedure. A single crystal X-ray structure analysis of H(2)tfBDC (1) confirms former data obtained for a deuterated sample (P1, Z = 1). Recrystallization from water/acetone leads to single crystals of H(2)tfBDC·2H(2)O (2, P2(1)/c, Z = 2), where an extensive hydrogen bonding network is found. By reacting H(2)tfBDC with an aqueous ammonia solution, single crystals of (NH(4))(2)tfBDC (3, C2/m, Z = 2) are obtained. 3 is thermally stable up to 250 °C and shows an enhanced solubility in water compared to H(2)tfBDC. Monosubstituted 2,3,5,6-tetrafluorobenzoic acid (H(2)tfBC, 4) is obtained by reacting 1,2,4,5-tetrafluorobenzene with stoichiometric amounts (1 equiv) of n-butyllithium in THF. Its crystal structure (Fdd2, Z = 16) shows dimeric units as characteristic structural feature.

Bright luminescence in lanthanide coordination polymers with tetrafluoroterephthalate as a bridging ligand.

Ten new coordination polymers of the general compositions ∞²[Ln(III)(tfBDC)(NO3)(DMF)2]·DMF with Ln(III) = Eu(3+) (1), Gd(3+) (2), Tb(3+) (3), Ho(3+) (4), Tm(3+) (5), ∞²[Ln(III)(tfBDC)(CH3COO)(FA)3]·3FA with Ln(III) = Sm(3+) (6), Eu(3+) (7) and ∞²[Ln(III)(tfBDC)(NO3)(DMSO)2] with Ln(III) = Ho(3+) (8), Er(3+) (9) and Tm(3+) (10) were synthesized and structurally characterized by X-ray single crystal diffraction (tfBDC(2-) = 2,3,5,6-tetrafluoroterephthalate, DMF = N,N'-dimethylformamide, FA = formamide, DMSO = dimethyl sulfoxide). 1-5 crystallize in the monoclinic space group C2/c with Z = 8, 6 and 7 in P1̄ with Z = 2 and 8-10 in Pbca with Z = 8. All crystal structures contain binuclear lanthanide nodes that are connected by 2,3,5,6-tetrafluoroterephthalates (tfBDC(2-)) to form two-dimensional polymeric structural units. Despite this common structural feature the coordination within these binuclear units is quite different in detail, e.g. CN = 9 for 1-7 and CN = 8 for 8-10. The emission spectra of the europium (1, 7) and terbium (3) compounds reveal bright red and green emission in the visible region. The resulting high quantum yields of 53% (1) and 67% (3) at room temperature show that the replacement of organic ligands with C-H groups by perfluorinated ligands leads to compounds with intense emission, as vibrational quenching is reduced. On the other hand, the influence of the coordinating solvent and additional ligands cannot be neglected, as the replacement of DMF by FA and NO3(-) by CH3COO(-) in 7 leads to a reduced quantum yield of only 10%. Thermoanalytical investigations show that all compounds are stable up to 100-150 °C, before a stepwise release of solvent molecules starts followed by a decomposition of the coordination polymer.

Influence of prebiotics and antioxidants in bread on the immune system, antioxidative status and antioxidative capacity in male smokers and non-smokers.

Interest in functional foods is increasing. The aim of the present study was to investigate breads supplemented with functional components. One was bread supplemented with inulin, linseed and soya fibre (prebiotic bread). The other was a prebiotic antioxidant bread (pre-aox-bread), which additionally contained green tea powder, herbs and tomato paste. The effects of these two breads on immunological and antioxidative parameters were compared with control bread (placebo). Twenty smokers and eighteen non-smokers were enrolled in the randomised parallel study, which consisted of a control period and an intervention period, each lasting for 5 weeks. Daily intake of bread and nutrients did not differ between the intervention and the control period. Most of the twenty-three investigated immunological parameters measured in peripheral blood were unaffected. However, the percentage of CD19 increased after intervention with prebiotic bread, whereas intercellular adhesion molecule-1 (ICAM-1) and CD3+NK+ (P < 0.05) decreased in both intervention arms. The ferric reducing ability of plasma (FRAP) was increased after consumption of the pre-aox-bread for non-smokers (1256 v. 1147 micromol/l; P = 0.019) and remained unchanged for smokers consuming the pre-aox-bread. All analysed carotenoids (P

Effects of fat-modified dairy products on blood lipids in humans in comparison with other fats.

BACKGROUND/AIM: Due to its high content of LDL-raising saturated fatty acids (SFA), milk fat has been considered to be hypercholesterolaemic, but it also contains fatty acids and other constituents which seem to have a hypocholesterolaemic effect. Milk fat was modified by feeding cows rapeseed cake, resulting in a reduced content of SFA and an increased content of unsaturated fatty acids. The objective of this study was to investigate the effects of modified milk fat (ModFat) on serum cholesterol fractions, triacylglycerides (TAG) and lipoprotein(a) [LP(a)], compared with regular milk fat (RegFat) and with soft margarine (Marg). METHOD: Fifteen women and 16 men were enrolled in the intervention study. Nine of the participants were hypercholesterolaemic. Nutrient intake parameters, serum lipids and LP(a) were determined. RESULTS: The serum concentration of HDL cholesterol increased in the ModFat period, leading to a decreased LDL/HDL ratio in this period. The lowest LP(a) concentrations were measured at the end of the control phase and at the end of the ModFat period. A decreasing tendency of serum TAG concentration was observed in the ModFat period. CONCLUSION: The fat-modified milk seems to have positive effects on the LDL/HDL ratio and the LP(a) concentrations, both of which have been established as risk factors for coronary heart disease.