Bis[µ-1,1'-methyl-enebis(1H-imidazole)-κN:N]bis-[dichloridocobalt(II)].

The title compound, [Co(2)Cl(4)(C(7)H(8)N(4))(2)], contains a dinuclear complex molecule in which each Co(II) atom is tetra-hedrally coordinated by two N atoms and two chloride ions. The 1,1'-methyl-enebis(1H-imidazole) ligands adopt a bis-monodentate bridging mode linking two Co(II) atoms.

Poly[[(µ(3)-2,4,6-tri-4-pyridyl-1,3,5-triazine)copper(I)] nitrate monohydrate].

In the title compound, {[Cu(C(18)H(12)N(6))]NO(3)·H(2)O}(n), the Cu(I) ion is coordinated by three N atoms [Cu-N 1.962 (3)-2.019 (3) Å] from three 2,4,6-tri-4-pyridyl-1,3,5-triazine (L) ligands. Each L ligand bridges three Cu(I) atoms, generating a positively charged three-dimensional polymeric network with voids propagated along the b axis. These voids are filled with NO(3) (-) anions with a shortest Cu⋯O distance of 2.645 (3) Šand water mol-ecules, which are linked into negatively charged helical chains via inter-molecular O-H⋯O hydrogen bonds.

Tetra-kis(2,2'-bipyrid-ine)di-µ(3)-hydroxido-bis(µ-2-oxidobenzoato)tetra-copper(II) dinitrate tetra-hydrate.

The tetra-nuclear title complex, [Cu(4)(C(7)H(4)O(3))(2)(OH)(2)(C(10)H(8)N(2))(4)](NO(3))(2)·4H(2)O, has a crystallographically imposed centre of symmetry. The Cu(II) atoms display a distorted square-pyramidal coordination geometry and are linked by two µ(2)-phenolate O atoms from the salicylate ligands and two µ(3)-hydroxo groups, forming a Cu(4)O(4) core that adopts a 'stepped-cubane' geometry. In the crystal, the cations are linked by O-H⋯O hydrogen bonds to the nitrate anions, which are in turn connected via O-H⋯O inter-actions to centrosymmentric water tetra-mers.

catena-Poly[[diaqua-bis-(formato-κO)nickel(II)]-µ-2,4,6-tris-(4-pyrid-yl)-1,3,5-triazine-κN:N].

In the title compound, [Ni(CHO(2))(2)(C(18)H(12)N(6))(H(2)O)(2)](n), the Ni(II) ion, lying on a crystallographic inversion center, has a distorted octa-hedral coordination comprising two water ligands, two O-atom donors from formate ligands and two N-atom donors from the 2,4,6-tris-(4-pyrid-yl)-1,3,5-triazine ligands. These ligands bridge the Ni(II) complex units, forming zigzag chains along the c axis. Adjacent chains are linked by O-H⋯O hydrogen bonds, forming a three-dimensional supra-molecular network.

[Construction of the dioxin bioassay method based on the clonal expressed aryl hydrocarbon receptor system].

OBJECTIVE: To study the specific binding of the artificial clonal aryl hydrocarbon receptor translocator (ARNT) with the natural aryl hydrocarbon receptor (AhR) and the recolonization by polyclonal antibody. The dose-response relationship with tetrachlo-rodibenzo-dioxin (TCDD) was also studied to develop TCDD detection method and the binding degree related to dose response. METHODS: (1) The target genes including AhR-PAS, AhR-C and ARNT-PAS were amplified by RT-PCR by using the total RNA purified from the liver cells of C57BL/6J mice as templates to construct pGEX-5X1 recombinants. The recombinant plasmids were expressed in E. coli. (2) The rabbits were immuned by the clonal fusion proteins: AhR-PAS, AhR-C to prepare the polyclonal antibody. (3) The natural AhR from the hepatic cytosol of C57BL/6J mice was extracted. The artificial cloning expressed fusion protein:GST-ARNT-PAS and the natural AhR were incubated in different dose of TCDD. The quantity of the heterodimer through affinity adsorption and Western blots were measured. RESULTS: (1) The target proteins including AhR-PAS, AhR-C and ARNT-PAS were successfully cloned and expressed in E. coli. (2) The detection limit of polyclonal antibody AhR-PAS and AhR-C were 5 ng and 1 ng, respectively. (3) The total protein concentration prepared from the liver cells was 60.5 mg/ml. The artificial clonal protein ARNT-PAS could specifically bind to the natural AhR complex with the existence of TCDD. The detection limit of TCDD was 0.25 pmol which was 80 pg approximately. CONCLUSION: A TCDD detection method based on the aryl hydrocarbon receptor system was established and the detection limit might reach pg grade.

LEF-1 negatively controls interleukin-4 expression through a proximal promoter regulatory element.

Lymphoid enhancer-binding factor 1 (LEF-1) and T cell factor (TCF-1) are downstream effectors of the Wnt signaling pathway and are involved in the regulation of T cell development in the thymus. LEF-1 and TCF-1 are also expressed in mature peripheral primary T cells, but their expression is down-regulated following T cell activation. Although the decisive roles of LEF-1 and TCF-1 in the early stages of T cell development are well documented, the functions of these factors in mature peripheral T cells are largely unknown. Recently, LEF-1 was shown to suppress Th2 cytokines interleukin-4 (IL-4), -5, and -13 expression from the developing Th2 cells that overexpress LEF-1 through retrovirus gene transduction. In this study, we further investigated the expression and functions of LEF-1 and TCF-1 in peripheral CD4+ T cells and revealed that LEF-1 is dominantly expressed in Th1 but not in Th2 cells. We identified a high affinity LEF-1-binding site in the negative regulatory element of the IL-4 promoter. Knockdown LEF-1 expression by LEF-1-specific small interfering RNA resulted in an increase in the IL-4 mRNA expression. This study further confirms a negative regulatory role of LEF-1 in mature peripheral T cells. Furthermore, we found that IL-4 stimulation possesses a negative effect on the expressions of LEF-1 and TCF-1 in primary T cells, suggesting a positive feedback effect of IL-4 on IL4 gene expression.

Oxidative DNA cleavage by Schiff base tetraazamacrocyclic oxamido nickel(II) complexes.

Nickel is considered a weak carcinogen. Some researches have shown that bound proteins or synthetic ligands may increase the toxic effect of nickel ions. A systematic study of ligand effects on the interaction between nickel complexes and DNA is necessary. Here, we compared the interactions between DNA and six closely related Schiff base tetraazamacrocyclic oxamido nickel(II) complexes NiL(1-3a,1-3b). The structure of one of the six complexes, NiL(3b) has been characterized by single crystal X-ray analysis. All of the complexes can cleave plasmid DNA under physiological conditions in the presence of H(2)O(2). NiL(3b) shows the highest DNA cleavage activity. It can convert supercoiled DNA to nicked DNA then linear DNA in a sequential manner as the complex concentration or reaction time is increased. The cleavage reaction is a typical pseudo-first-order consecutive reaction with the rate constants of 3.27+/-0.14h(-1) (k(1)) and 0.0966+/-0.0042h(-1) (k(2)), respectively, when a complex concentration of 0.6mM is used. The cleavage mechanism between the complex and plasmid DNA is likely to involve hydroxyl radicals as reactive oxygen species. Circular dichronism (CD), fluorescence spectroscopy and gel electrophoresis indicate that the complexes bind to DNA by partial intercalative and groove binding modes, but these binding interactions are not the dominant factor in determining the DNA cleavage abilities of the complexes.

Protein-imprinted polymer with immobilized assistant recognition polymer chains.

Here we introduce a new method for preparing a protein-imprinted polymer with immobilized assistant recognition polymer chains as an additional element of monomer to create effective recognition sites. In this work the bovine serum albumin was used as template and the template protein was selectively assembled with immobilized assistant recognition polymer chains from their library, numerous limited length polymer chains with randomly distributed recognition sites and immobilizing sites. These assemblies of protein and immobilized assistant recognition polymer chains would be adsorbed by the macro porous adsorbent spheres and immobilized by cross-linking polymerization. After removing the template, binding sites that were complementary to the target protein in size, shape and position of recognition groups were exposed, and their confirmation was preserved by the cross-linked structure. The synthesized imprinted polymer was used to adsorb BSA from protein mixtures, and showed a high selectivity.

A modified molecular beacon combining the properties of TaqMan probe.

A modified molecular beacon that possesses a stem-hairpin structure as seen in conventional molecular beacons and can be cleaved during PCR in designed, and it can specifically recognize the presence of the target and was obviously more sensitive than conventional molecular beacons.