Polymorphism of a chiral iron(ii) complex: spin-crossover and ferroelectric properties.

Two solvent-free polymorphs of a chiral iron(ii) complex have been obtained, and their polymorphism dependent spin-crossover and ferroelectric properties have been demonstrated. Polymorph I shows a gradual spin-crossover behavior, whereas polymorph II remains in a high-spin state but shows a typical ferroelectric feature.

Spin crossover properties of enantiomers, co-enantiomers, racemates, and co-racemates.

Through multi-component self-assembly of chiral phenylethylamine, 1-alkyl-2-imidazolecarboxaldehyde and iron(ii) ions, two couples of enantiomeric iron(ii) complexes , , and with the formula of fac-Λ or Δ-[Fe(L)3](2+)(L = R or S-1-phenyl-N-(1-alkyl-1H-imidazol-2-ylmethylene)ethanamine) have been designed and synthesized as building blocks. Further binary cocrystallization of the prefabricated enantiomers enabled us to construct spin crossover co-enantiomers and , racemates and , and co-racemate . Compared with in a high spin state and with spin crossover at 291 K, the co-enantiomers exhibited gradual spin crossover at a higher temperature of 301 K, and the racemic alloys showed hysteresis loops induced by desolvation above room temperature. It was demonstrated that molecular chirality could be used effectively for stereochemical engineering of spin crossover materials. In addition, crystal packing, intramolecular π-π stacking, intermolecular C-Hπ interactions and solvent effects were elucidated to be responsible for the distinct spin crossover properties. This collective structural and magnetic study not only enriched the spin crossover library, but also provided a full comparison of optically pure, homochiral, and racemic materials with similar molecular structures.

Chiral tetrahedral iron(II) cages: diastereoselective subcomponent self-assembly, structure interconversion and spin-crossover properties.

A new class of chiral tetrahedral iron(II) cages were prepared from subcomponent self-assembly with high diastereoselectivity. The cages can be interconverted through imine exchange. The chiral cages displayed a spin transition close to room temperature, and the transition temperatures were affected by the substituent and uncoordinated solvents.

Enantioselective DNA condensation induced by heptameric lanthanum helical supramolecular enantiomers.

DNA condensation induced by a pair of heptameric La(III) helical enantiomers M-[La7(S-L)6(CO3)(NO3)6(OCH3)(CH3OH)7]·2CH3OH·5H2O and P-[La7(R-L)6(CO3)(NO3)6(OCH3)(CH3OH)5(H2O)2]·2CH3OH·4H2O (M-La and P-La, L=2-(2-hydroxybenzylamino)-3-carbamoylpropanoic acid) has been investigated by UV/vis spectroscopy, fluorescence spectroscopy, CD spectroscopy, EMSA, RALS, DLS, and SEM. The enantiomers M-La and P-La could induce CT-DNA condensation at a low concentration as observed in UV/vis spectroscopy. DNA condensates possessed globular nanoparticles with nearly homogeneous sizes in solid state determined by SEM (ca. 250 nm for M-La and ca. 200 nm for P-La). The enantiomers bound to DNA through electrostatic attraction and hydrogen bond interactions in a major groove, and rapidly condensed free DNA into its compact state. DNA decompaction has been acquired by using EDTA as disassembly agent, and analyzed by UV/vis spectroscopy, CD spectroscopy and EMSA. Moreover, the enantiomers M-La and P-La displayed discernible discrimination in DNA interaction and DNA condensation, as well as DNA decondensation. Our study suggested that lanthanum(III) enantiomers M-La and P-La were efficient DNA packaging agents with potential applications in gene delivery.

Dinuclear nickel(II) triple-stranded supramolecular cylinders: syntheses, characterization and G-quadruplexes binding properties.

Three dinuclear nickel triple-stranded supramolecular cylinders [Ni2(L1)3][ClO4]4 (1), [Ni2(L2)3][ClO4]4 (2) and [Ni2(L3)3][ClO4]4 (3) with bis(pyridylimine) Schiff base containing triphenyl groups in the spacers as ligands were synthesized and characterized. The human telomeric G-quadruplexes binding properties of cylinders 1-3 were evaluated by means of UV-Vis spectroscopy, circular dichroism (CD) spectroscopy and fluorescence resonance energy transfer (FRET) melting assay. UV-Vis studies revealed that the supramolecular cylinders 1-3 could bind to G-quadruplex DNA with high binding constants (Kb values ranging from 0.11-2.2×10(6) M(-1)). FRET melting studies indicated that the cylinders 1-3 had much stronger stabilizing effect on G-quadruplex DNA (ΔTm up to 24.5°C) than the traditional cylinder Ni2L3(4+) just containing diphenylmethane spacers (ΔTm=10.6 °C). Meanwhile, cylinders 1-3 were found to have a modest degree of selectivity for the quadruplex DNA versus duplex DNA in competition FRET assays. Moreover, CD spectroscopy revealed that complex 1 could induce G-quadruplex formation in the absence of metal ions solution and convert antiparallel G-quadruplex into hybrid structure in Na(+) solution. These results provided a new insight into the development of supramolecular cylinders as potential anticancer drugs targeting G-quadruplex DNA.

[Immunization with 2nd extracellular loop peptide of muscarinic acetylcholine 3 receptor induces the secretion of IL-17 and IFN-γ in NOD-scid mice].

AIM: To evaluate whether or not the changes in the secretions of IL-17 and IFN-γ can be induced by the immunization with 2nd extracellular loop peptide of muscarinic acetylcholine 3 receptor (M3R) in NOD-scid (nonobese diabetic-severe combined immunodeficiency) mice. METHODS: We synthesized the 2nd extracellular loop peptide of M3R and immunized NOD-scid mice subcutaneously with the 1:1 mixture of the peptide and the incomplete Freund's adjuvant (IFA). At day 1, 7, 14, 21 after immunization, tail blood samples were taken to determine the antibody titer and evaluate the secretions of IL-17 and IFN-γ in sera. Meanwhile, we recorded the fluid intake amount per mouse every week. At day 21, all of the NOD-scid mice were killed to measure the concentrations of IL-17 and IFN-γ in cell supernatants. Immunofluorescence staining of lacrimal glands was performed to observe the changes in the secretions of IL-17 and IFN-γ. RESULTS: Compared with the control group, the sera titers of anti-2nd extracellular loop peptide antibodies were significantly higher in 2nd extracellular loop peptide immunized NOD-scid mice at day 14 (P<0.05). The concentrations of IL-17 and IFN-γ increased significantly in sera of the 2nd extracellular loop peptide immunized NOD-scid mice at day 7 and 14 (P<0.01). The concentration of IL-17 maintained at a certain level in the supernatants of spleen cells co-cultured with 2nd extracellular loop peptide, while it decreased significantly in the control groups (P<0.01). Immunofluorescence staining demonstrated that the production of IL-17 and IFN-γ increased in the lacrimal glands of NOD-scid mice immunized with the 2nd extracellular loop peptide. However, no changes in fluid intake was observed in NOD-scid mice immunized with the 2nd extracellular loop peptide(P>0.05). CONCLUSION: Immunization with 2nd extracellular loop peptide of M3R can induce the production of anti-2nd extracellular loop peptide antibodies and the secretions of IL-17 and IFN-γ in NOD-scid mice.

Hexa-kis-(µ2-4-amino-3,5-dimethyl-4H-1,2,4-triazole)hexa-aqua-tricobalt(II) naphthalene-1,5-disulfonate tetra-chloride.

In the centrosymmetric trinuclear cation of the title compound, [Co3(C4H(8)N4)6(H2O)6](C10H6O6S2)Cl4, the three Co(II) atoms are bridged by six triazole mol-ecules via the N atoms in the 1,2-positions. The central Co(II) atom, lying on an inversion center, is coordinated by six triazole N atoms while the terminal Co(II) atoms are coordinated by three triazole N atoms and three water O atoms in a distorted octa-hedral geometry. The naphthalene-disulfonate anion is also centrosymmetric. The four chloride counter anions are half-occupied; the H atoms of the amino groups show an occupancy of 2/3. O-H⋯Cl, O-H⋯O and N-H⋯O hydrogen bonds link the complex cations and the chloride and naphthalene-1,5-disulfonate anions.

[Role of glucocorticoid receptor in the pathogenesis of systemic lupus erythematosus].

OBJECTIVE: To investigate the expressions of GRα mRNA and GRß mRNA in the peripheral blood mononuclear cells (PBMCs) of systemic lupus erythematosus (SLE) patients, in order to reveal the role of GR mRNA in the pathogenesis of SLE and analyze the relationship between GR mRNA and SLEDAI score, dsDNA, cardiovascular involvement. METHODS: Reverse transcription-polymerase chain reaction (RT-PCR) technique was applied to semiquantitatively analyze GRα mRNA and GRß mRNA expressions in 104 SLE patients and 56 volunteers. RESULTS: The level of GRα mRNA was lower in the SLE group (the relative level was 1.24±0.97)than in the control group (the relative level was 2.31±1.42, P<0.05), and the level of GRß mRNA was higher in the SLE group(the relative level was 0.61±1.23) than in the control group(the relative level was 0.18±0.21, P<0.05). The level of GRα was lower in the active group (the relative level was 0.68±0.40) than in the inactive group(the relative level was 1.65±1.06, P<0.01), but the level of GRß was higher in the active group(the relative level was 0.88±1.56) than in the inactive group(the relative level was 0.24±0.23, P<0.01); GRα mRNA was related negatively to the SLEDAI score and dsDNA, but GRß mRNA was related positively to the SLEDAI score and dsDNA(P<0.01).The level of GRα mRNA was lower in the dsDNA positive group(the relative level was 0.89±0.66) than in the dsDNA negative group (the level was 1.54±1.10), the level of GRß mRNA was higher in the dsDNA positive group (the relative level was 0.95±1.60) than in the dsDNA negative group (the relative level was 0.22±0.21). The level of GRß mRNA and the value of GRß mRNA/ GRα mRNA was obviously higher in the SLE group with cardiac involvement (the relative level was 1.02 ±1.76, the valve of GRß / GRα was 1.10±2.02)than in the SLE group without cardiac involvement (the relative level was 0.28±0.31, the valve of GRß / GRα was 0.32±0.32, P<0.05), and the level of GRα mRNA wasn't significant in the two groups (P>0.05). CONCLUSION: The levels of GRα mRNA and GRß mRNA maybe play an important role in the pathogenesis of SLE. And the levels of GRα mRNA and GRß mRNA are related to the activity of SLE. The level of GRß mRNA and the value of GRß mRNA/ GRα mRNA are related with cardiovascular involvement in SLE.

A new type of entangled coordination network: coexistence of polythreading and polyknotting involved molecular braids.

A fascinating polythreaded coordination network formed by 1D crankshaft shaped chains threading into a 2D undulated sheet in a one-over/one-under interweaving fashion was reported, in which the 2D layer exhibits an unusual polyknotted entanglement containing triple-stranded molecular braids.

[Effects of microcystins on expression of apoptosis-associated hepatocyte genes].

OBJECTIVE: To deeply explore the effects of microcystins (MC-LR) on Bax and Bcl-2 during the course of MC-LR promoting liver tumor. METHODS: applied to set up the animal model, and the effect of MC-LR promoting liver tumor was evaluated by the Albertgamma-GT methods. And then, the immunohistochemical technique, RT-PCR and image analysis were used to study the expression of the Bcl-2 and Bax during the course of promoting tumor. RESULTS: (1) MC-LR might enhance the positive reaction rate of GGT. The positive reaction rate of GGT in DEN + pure toxin group was 100%, it was significantly higher than the DEN control group 22.22% (P < 0.05). (2) The intension and areas of the protein expression of Bcl-2 in DEN + pure toxin group were 0.0977 and 0.0315, and in DEN control group were 0.0460 and 0.0205, respectively. The expression level of Bcl-2 protein in DEN + pure toxin group were significantly higher than in DEN control group (P < 0.05). Simultaneously, the protein expression of Bax was significantly decreased by MC-LR (P < 0.05). The intension and areas of the expression of Bax in DEN + pure toxin group were 0.0283 and 0.0073, and in DEN control group were 0.0655 and 0.0244 respectively. (3) The mRNA expression of Bcl-2 was significantly increased by MC-LR. The intension of Bcl-2 mRNA expression in DEN + pure toxin group was 2.244, being significantly higher than in the other groups (P < 0.05). However, the mRNA expression of Bax showed no significant difference between DEN + pure toxin and the other groups. CONCLUSION: The expression change of Bcl-2 and Bax should possibly play an important role in the course of MC-LR promoting liver tumor.