4,4′-Bipyridine-1,1′-diium 2,3,5,6-tetra­bromo­terephthalate dihydrate

The title compound, C10H10N2 2+·C8Br4O4 2−·2H2O, consists of a tetra­bromo­terephthalate dianion, a 4,4′-bipyridinium dication and two solvent water mol­ecules. Crystallographic inversion centers are situated at the center of the aromatic ring of the dianion as well as at the midpoint of the carbon–carbon bond connecting the pyridine rings in the dication. In the crystal, inter­molecular N—H⋯O hydrogen-bonding inter­actions between tetra­bromo­terephthalate dianions and protonated 4,4′-bipyridinium dications result in the formation of a chain-like structure. Further O—H⋯O hydrogen bonds between carboxyl­ate O atoms and water mol­ecules lead to the formation of a two-dimensional network in the crystal structure

Poly[[dodeca­aqua­(μ4-benzene-1,4-dicarboxyl­ato)(μ2-4,4′-bipyridine-κ2 N:N′)dicerium(III)] bis­(benzene-1,4-dicarboxyl­ate)]

The asymmetric unit of the title compound, {[Ce2(C8H4O4)(C10H8N2)(H2O)12](C8H4O4)2}n, consists of half a CeIII cation, a quarter of a coordinated benzene-1,4-dicarboxyl­ate (bdc2−) dianion, a quarter of a 4,4′-bipyridine (bpy) mol­ecule, three water mol­ecules and a half of an uncoordinated benzene-1,4-dicarboxyl­ate dianion. The CeIII ion is located on a twofold rotation axis and exhibits a distorted trigonal prism square-face tricapped coordination geometry. The coordinated and uncoordinated bdc2− ions and the bpy mol­ecule lie about special positions of site symmetries 2/m, m and 2/m, respectively. The CeIII ions are bridged by the bdc2− and bpy ligands, giving a sheet structure parallel to the ac plane. The uncoordinated bdc2− dianion exists between the sheets and links the sheets by inter­molecular O—H⋯O hydrogen bonds between the uncoordinated bdc2− and coordinated water mol­ecules. A π–π stacking inter­action between the uncoordinated bdc2− dianion and the bpy ligand [centroid–centroid distance = 3.750 (4) Å] is also observed

Molecular and Genetic Interactions between CCN2 and CCN3 behind Their Yin-Yang Collaboration

Cellular communication network factor (CCN) 2 and 3 are the members of the CCN family that conduct the harmonized development of a variety of tissues and organs under interaction with multiple biomolecules in the microenvironment. Despite their striking structural similarities, these two members show contrastive molecular functions as well as temporospatial emergence in living tissues. Typically, CCN2 promotes cell growth, whereas CCN3 restrains it. Where CCN2 is produced, CCN3 disappears. Nevertheless, these two proteins collaborate together to execute their mission in a yin-yang fashion. The apparent functional counteractions of CCN2 and CCN3 can be ascribed to their direct molecular interaction and interference over the cofactors that are shared by the two. Recent studies have revealed the mutual negative regulation systems between CCN2 and CCN3. Moreover, the simultaneous and bidirectional regulatory system of CCN2 and CCN3 is also being clarified. It is of particular note that these regulations were found to be closely associated with glycolysis, a fundamental procedure of energy metabolism. Here, the molecular interplay and metabolic gene regulation that enable the yin-yang collaboration of CCN2 and CCN3 typically found in cartilage development/regeneration and fibrosis are described

Self-written waveguides in photopolymerizable resins

We study the optically-induced growth and interaction of self-written waveguides in a photopolymerizable resin. We investigate experimentally how the interaction depends on the mutual coherence and relative power of the input beams, and suggest an improved analytical model that describes the growth of single self-written waveguides and the main features of their interaction in photosensitive materials.Comment: 3 pages, 3 figure

Evidence of introgressive hybridization between the morphologically divergent land snails Ainohelix and Ezohelix

Hybridization between different taxa is likely to take place when adaptive morphological differences evolve more rapidly than reproductive isolation. When studying the phylogenetic relationship between two land snails of different nominal genera, Ainohelix editha and Ezohelix gainesi, from Hokkaido, Japan, using nuclear internal transcribed spacer and mitochondrial 16S ribosomal DNA, we found a marked incongruence in the topology between nuclear and mitochondrial phylogenies. Furthermore, no clear association was found between shell morphology (which defines the taxonomy) and nuclear or mitochondrial trees and morphology of reproductive system. These patterns are most likely explained by historical introgressive hybridization between A. editha and E. gainesi. Because the shell morphologies of the two species are quite distinct, even when they coexist, the implication is that natural selection is able to maintain (or has recreated) distinct morphologies in the face of gene flow. Future studies may be able to reveal the regions of the genome that maintain the morphological differences between these species

Retrotransposons Manipulating Mammalian Skeletal Development in Chondrocytes

Retrotransposons are genetic elements that copy and paste themselves in the host genome through transcription, reverse-transcription, and integration processes. Along with their proliferation in the genome, retrotransposons inevitably modify host genes around the integration sites, and occasionally create novel genes. Even now, a number of retrotransposons are still actively editing our genomes. As such, their profound role in the evolution of mammalian genomes is obvious; thus, their contribution to mammalian skeletal evolution and development is also unquestionable. In mammals, most of the skeletal parts are formed and grown through a process entitled endochondral ossification, in which chondrocytes play central roles. In this review, current knowledge on the evolutional, physiological, and pathological roles of retrotransposons in mammalian chondrocyte differentiation and cartilage development is summarized. The possible biological impact of these mobile genetic elements in the future is also discussed

Expression and function of CCN2-derived circRNAs in chondrocytes

Cellular communication network factor 2 (CCN2) molecules promote endochondral ossification and articular cartilage regeneration, and circular RNAs (circRNAs), which arise from various genes and regulate gene expression by adsorbing miRNAs, are known to be synthesized from CCN2 in human vascular endothelial cells and other types of cells. However, in chondrocytes, not only the function but also the presence of CCN2-derived circRNA remains completely unknown. In the present study, we investigated the expression and function of CCN2-derived circRNAs in chondrocytes. Amplicons smaller than those from known CCN2-derived circRNAs were observed using RT-PCR analysis that could specifically amplify CCN2-derived circRNAs in human chondrocytic HCS-2/8 cells. The nucleotide sequences of the PCR products indicated novel circRNAs in the HCS-2/8 cells that were different from known CCN2-derived circRNAs. Moreover, the expression of several Ccn2-derived circRNAs in murine chondroblastic ATDC5 cells was confirmed and observed to change alongside chondrocytic differentiation. Next, one of these circRNAs was knocked down in HCS-2/8 cells to investigate the function of the human CCN2-derived circRNA. As a result, CCN2-derived circRNA knockdown significantly reduced the expression of aggrecan mRNA and proteoglycan synthesis. Our data suggest that CCN2-derived circRNAs are expressed in chondrocytes and play a role in chondrogenic differentiation