HSC70-JNK-BAG3 complex is critical for cardiomyocyte protection of BAG3 through its PXXP and BAG structural domains.

Notwithstanding previous studies have proved the anti-apoptotic effect of Bcl-2 associated athanogene3 (BAG3) in myocardium, the structural domains PXXP and BAG responsible for its protection are not reformed. Since BAG3 in cardiomyocytes is a new target for inhibiting apoptosis induced by hypoxia/reoxygenation (H/R) stress, we demonstrated that over-expression of BAG3 reduced the injury induced by H/R in either neonatal or adult rat cardiomyocytes (NRCMs and ARCMs, respectively) and PXXP and BAG domains play an important role in cellular protection in H/R stress. Apoptosis in cardiomyocytes induced by hypoxia-reperfusion was evaluated with propidium iodide (PI) staining, cleaved caspase-3, and terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) staining in cultured NRCMS. Either increasing expression of BAG3 or its mutants was performed to manipulate the level of BAG3. Co-immunoprecipitation (Co-IP) was used to demonstrate the complex that BAG3 is binding to HSC70 and JNK. PXXP and BAG domains of BAG3 played an essential role in BAG3 attenuating cardiomyocytes apoptosis induced by H/R through the JNK signalling pathway. The cellular protection of BAG3 with its structural domain PXXP or BAG is associated with the binding with HSC70 and JNK. These results showed that the protective effect of BAG3 on apoptosis induced by H/R stress is closely related to its structural domains PXXP and BAG. The mechanism may provide a new therapeutic strategy for the patients suffering from ischemic cardiomyopathy and may be a critical role of its PXXP and BAG3 domains.

Coordination-Directed Construction of Molecular Links.

Since the emergence of the concept of chemical topology, interlocked molecular assemblies have graduated from academic curiosities and poorly defined species to become synthetic realities. Coordination-directed synthesis provides powerful, diverse, and increasingly sophisticated protocols for accessing interlocked molecules. Originally, metal ions were employed solely as templates to gather and position building blocks in entwined or threaded arrangements. Recently, metal centers have increasingly featured within the backbones of the integral structural elements, which in turn use noncovalent interactions to self-assemble into intricate topologies. By outlining ingenious recent examples as well as seminal classic cases, this Review focuses on the role of metal-ligand paradigms in assembling molecular links. In addition, the ever-evolving approaches to efficient assembly, the structural features of the resulting architectures, and their prospects for the future are also presented.

Discrete Supramolecular Stacks Based on Multinuclear Tweezer-Type Rhodium Complexes.

By taking advantage of self-complementary π-π stacking and CH-π interactions, a series of discrete quadruple stacks were constructed through the self-aggregation of U-shaped dirhodium metallotweezer complexes featuring various planar polyaromatic ligands. By altering the conjugate stacking strength and bridging ligands, assemblies with a range of topologies were obtained, including a binuclear D-shaped macrocycle, tetranuclear open-ended cagelike frameworks, and duplex metallotweezer stacking structures. Furthermore, a rare stacking interaction resulting in selective C-H activation was observed during the self-assembly process of these elaborate architectures.

Design of and Stability Studies on Trefoil Knots Featuring RhCp* Building Blocks.

Four flexible ligands with different lengths, degrees of flexibility, and steric bulk were synthesized and used to prepare metal-directed assemblies. Interestingly, minor differences among the ligands led to products with dramatically different topologies: a binuclear D-shaped macrocycle, tetranuclear rectangles, and hexanuclear trefoil knots. The interconversion of the trefoil-shaped complexes was also investigated. This contribution introduces a rare ligand-controlled trefoil-rectangle shape transformation in solution.

Construction of half-sandwich multinuclear complexes including tunnel architectures via C-H-activation-directed assembly.

Three aromatic ligands containing carboxyl- or nitrogen-substituted groups were employed in the construction of half-sandwich complexes via C-H activation-directed assembly, leading to the construction of eleven multinuclear organometallic iridium or rhodium complexes, including those of bi-, tetra-, hexa- and octanuclear, under mild conditions, with the help of N-donor linkers. These complexes were characterized by proton NMR, IR spectroscopy, elemental analysis, electrospray ionization (ESI) mass spectrometry and single-crystal X-ray diffraction analysis. In these complexes, two complexes were observed to exist as isomers, and several racemic enantiomers can be found. X-ray crystal structure determinations show that a series of supramolecular tunnel architectures are formed by stacking through hydrogen-bond interactions, and solvent or trifluoromethylsulfonate anion guests were found to be located in certain parts of the channels. This work represents the first successful construction of octanuclear half-sandwich complexes based on the cleavage of C-H bonds.

Influences of graphene oxide on biofilm formation of gram-negative and gram-positive bacteria.

In this study, we evaluated the influences of graphene oxide (GO) on biofilm formation. Escherichia coli MG1655 and Bacillus subtilis 168 were used as models for Gram-negative and Gram-positive bacteria. The growth profiles and viability assays indicated that GO exhibited a high antibacterial activity, of which the negative effects on bacteria growth raised with the increasing GO concentration. The antibacterial activity of GO was mainly attributed to the membrane stress and ROS-independent oxidative stress. Moreover, it was worthy to note that the biofilm formation was enhanced in the presence of GO at low dosage whereas inhibited in the high-concentration GO environment. These results could be explained by the roles of the dead cells, which were inactivated by GO. When the concentration of GO was limited, only a part of the cells would be inactivated, which may then serve as a protection barrier as well as the necessary nutrient to the remaining living cells for the formation of biofilm. In contrast, with a sufficient presence of GO, almost all cells can be inactivated completely and thus the formation of biofilm could no longer be triggered. Overall, the present work provides significant new insights on the influence of carbon nanomaterials towards biofilm formation, which has far-reaching implications in the field of biofouling and membrane bioreactor. Graphical abstract ᅟ.

Controllable construction of half-sandwich octanuclear complexes based on pyridyl-substituted ligands with conjugated centers.

Functional metal bis(1,3,5-triazapentadienato) units [M(tap)2] (M = NiII/PdII) and pyrene groups were introduced as central units of three tetradentate tetrapyridyl-substituted ligands, with which seven half-sandwich organometallic complexes were controllably synthesized. The multi-centered hybrid products constructed from the two [M(tap)2] units revealed delocalized π-bonding environments. The products were characterized by proton NMR and IR spectroscopy, elemental analyses and electrospray ionization (ESI) mass spectrometry. The molecular structures of four of the products were determined by X-ray diffraction analysis, revealing their octanuclear structures.

Assembly of a series of MOFs based on the 2-(m-methoxyphenyl)imidazole dicarboxylate ligand.

The coordination features of an imidazole dicarboxylate ligand, 2-(3-methoxyphenyl)-1H-imidazole-4,5-dicarboxylic acid (m-H(3)MOPhIDC) has been explored. Consequently, seven coordination polymers, namely [Sr(m-HMOPhIDC)(H(2)O)](n) (1), [Sr(m-H(2)MOPhIDC)(2)](n) (2), [Cd(3)(m-H(2)MOPhIDC)(2)(m-HMOPhIDC)(2)(H(2)O)(2)](n) (3), [Cu(m-HMOPhIDC)(phen)](n) (phen = 1,10-phenanthroline) (4), [Cd(2)(m-HMOPhIDC)(2)(phen)(2)](n) (5) [Cd(2)(m-HMOPhIDC)(2)(2,2'-bipy)(2)](n) (2,2'-bipy = 2,2'-bipyridine) (6) and [Co(m-HMOPhIDC)(H(2)O)(2)](n) (7) have been hydro(solvo)thermally synthesized by fine control over synthetic conditions, and structurally characterized. X-ray single-crystal analyses reveal that these polymers indicate rich structural chemistry ranging from one-dimensional (4-7), two-dimensional (1 and 3) to three-dimensional (2) structures, and the m-H(3)MOPhIDC ligand in these polymers can be singly deprotonated or doubly deprotonated, and coordinates to metal ions by various modes. The thermal and fluorescence properties of the complexes 1-7 have been determined as well.