Psychosine-triggered endomitosis is modulated by membrane sphingolipids through regulation of phosphoinositide 4,5-bisphosphate production at the cleavage furrow.

Endomitosis is a special type of mitosis in which only cytokinesis-the final step of the cell division cycle-is defective, resulting in polyploid cells. Although endomitosis is biologically important, its regulatory aspects remain elusive. Psychosine, a lysogalactosylceramide, prevents proper cytokinesis when supplemented to proliferating cells.

Highly Oriented J-Aggregates of Nitroazo Dye and Its Surface-Induced Chromism.

Highly oriented J-aggregates of a nitroazo dye were obtained in solid thin films on aligned poly(tetrafluoroethylene) surfaces. During film deposition on a friction-transferred poly(tetrafluoroethylene) layer, a sharp peak grew in the polarized absorption spectra around 613 nm, which was red-shifted 117 nm from the peak in dilute dichloromethane solution. The peak showed remarkable optical anisotropy: dichroic ratios D of up to 22 were observed, and the intrinsic D value should substantially exceed this value.

(Z)-1,2-Di(1-pyrenyl)disilene: Synthesis, Structure, and Intramolecular Charge-Transfer Emission.

(Z)-1,2-Di(1-pyrenyl)disilene containing bulky 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl (Eind) groups has been obtained as purple crystals by the reductive coupling reaction of the corresponding dibromosilane with lithium naphthalenide. An X-ray crystallographic analysis revealed an Eind- and pyrenyl-meshed molecular gear around the disilene core adopting the Z configuration, in which the two pyrenyl groups intramolecularly interact through the π-π stacking with a distance of 3.635 Å between the centers of the two pyrene rings.

A Boolean Function for Neural Induction Reveals a Critical Role of Direct Intercellular Interactions in Patterning the Ectoderm of the Ascidian Embryo.

A complex system of multiple signaling molecules often produce differential gene expression patterns in animal embryos. In the ascidian embryo, four signaling ligands, Ephrin-A.d (Efna.

Evaluation of the effect of post-translational modification toward protein structure: Chemical synthesis of glycosyl crambins having either a high mannose-type or a complex-type oligosaccharide.

Glycoproteins are assembled and folded in the endoplasmic reticulum (ER) and transported to the Golgi for further processing of their oligosaccharides. During these processes, two types of oligosaccharides are used: that is, high mannose-type oligosaccharide in the ER and complex-type oligosaccharide in the Golgi. We were interested to know how two different types of oligosaccharides could influence the folding pathway or the final three-dimensional structure of the glycoproteins.

Coplanar Oligo(p-phenylenedisilenylene)s as Si═Si Analogues of Oligo(p-phenylenevinylene)s: Evidence for Extended π-Conjugation through the Carbon and Silicon π-Frameworks.

A series of oligo(p-phenylenedisilenylene)s (Si-OPVs 1-4), silicon analogues of oligo(p-phenylenevinylene)s, up to the tetramer have been synthesized and isolated by the introduction of a newly developed protecting group [(HexO)MEind] for improving their solubility. The experimental and theoretical studies of the Si-OPVs 1-4 demonstrate the fully extended π-conjugation of the Si-OPV main chains. Single crystal X-ray analyses of the monomer 1 and the dimer 2 revealed the highly coplanar Si-OPV backbones facilitating the effective extension of the π-conjugation, which has further been validated by the significant increases in the absorption maxima from 465 nm for the monomer 1 to 610 nm for the tetramer 4.

Magnetic Field-Induced Insulator-Semimetal Transition in a Pyrochlore Nd2Ir2O7.

We investigate magnetotransport properties in a single crystal of pyrochore-type Nd2Ir2O7. The metallic conduction is observed on the antiferromagnetic domain walls of the all-in-all-out-type Ir 5d moment ordered insulating bulk state that can be finely controlled by an external magnetic field along [111]. On the other hand, an applied field along [001] induces the bulk phase transition from insulator to semimetal as a consequence of the field-induced modification of the Nd 4f and Ir 5d moment configurations.

tRNA-dependent alanylation of diacylglycerol and phosphatidylglycerol in Corynebacterium glutamicum.

Aminoacyl-phosphatidylglycerol synthases (aaPGSs) are membrane proteins that utilize aminoacylated tRNAs to modify membrane lipids with amino acids. Aminoacylation of membrane lipids alters the biochemical properties of the cytoplasmic membrane and enables bacteria to adapt to changes in environmental conditions. aaPGSs utilize alanine, lysine and arginine as modifying amino acids, and the primary lipid recipients have heretofore been defined as phosphatidylglycerol (PG) and cardiolipin.

Engineering a Spin-Orbital Magnetic Insulator by Tailoring Superlattices.

In 5d Ir oxides with an interplay of spin-orbit coupling and electron correlations, we have tailored a spin-orbital magnetic insulator out of a semimetal SrIrO(3) by tuning the structure through superlattices [(SrIrO(3))(m), SrTiO(3)] (m=1,2,3,4, and ∞). We observed the systematic decrease of the magnetic ordering temperature and the resistivity as a function of m. The transition from the semimetal to the insulator is found to be closely linked to the appearance of magnetism at m≃3.

Insect Gut Symbiont Susceptibility to Host Antimicrobial Peptides Caused by Alteration of the Bacterial Cell Envelope.

The molecular characterization of symbionts is pivotal for understanding the cross-talk between symbionts and hosts. In addition to valuable knowledge obtained from symbiont genomic studies, the biochemical characterization of symbionts is important to fully understand symbiotic interactions. The bean bug (Riptortus pedestris) has been recognized as a useful experimental insect gut symbiosis model system because of its cultivatable Burkholderia symbionts.

p38α controls self-renewal and fate decision of neurosphere-forming cells in adult hippocampus.

Neural stem cells (NSC) from the adult hippocampus easily lose their activity in vitro. Efficient in vitro expansion of adult hippocampus-derived NSC is important for generation of tools for research and cell therapy. Here, we show that a single copy disruption or pharmacological inhibition of p38α enables successful long-term neurosphere culture of adult mouse hippocampal cells.

Effect of microtubule polymerization on photoinduced hydrogen generation.

Herein we report a novel reaction field for photoinduced H2 generation by using microtubules as a medium. By controlling the tubulin/microtubule hierarchical structure, synergistic effects by which the Ru(bpy)3(2+)-conjugated microtubule network causes suppression of energy loss by collision are clarified.

Microtubule teardrop patterns.

Several strategies for controlling microtubule patterns are developed because of the rigidity determined from the molecular structure and the geometrical structure. In contrast to the patterns in co-operation with motor proteins or associated proteins, microtubules have a huge potential for patterns via their intrinsic flexural rigidity. We discover that a microtubule teardrop pattern emerges via self-assembly under hydrodynamic flow from the parallel bundles without motor proteins.

An efficient synthesis of SK-658 and its analogs as potent histone deacetylase inhibitors.

SK-658 is a potent histone deacetylase (HDAC) inhibitor that showed higher activity than SAHA due to the presence of extended hydrophobic group. We designed and synthesized thioester and SS-hybrid bearing SK-658 analogs as HDAC inhibitors. All the compounds were active in nano molar range and showed higher inhibitory activity than SAHA and SK-658.

Comparative genome and transcriptome analyses of the social amoeba Acytostelium subglobosum that accomplishes multicellular development without germ-soma differentiation.

Background: Social amoebae are lower eukaryotes that inhabit the soil. They are characterized by the construction of a starvation-induced multicellular fruiting body with a spore ball and supportive stalk. In most species, the stalk is filled with motile stalk cells, as represented by the model organism Dictyostelium discoideum, whose developmental mechanisms have been well characterized.

A novel cell-permeable, selective, and noncompetitive inhibitor of KAT3 histone acetyltransferases from a combined molecular pruning/classical isosterism approach.

Selective inhibitors of the two paralogue KAT3 acetyltransferases (CBP and p300) may serve not only as precious chemical tools to investigate the role of these enzymes in physiopathological mechanisms but also as lead structures for the development of further antitumor agents. After the application of a molecular pruning approach to the hardly optimizable and not very cell-permeable garcinol core structure, we prepared many analogues that were screened for their inhibitory effects using biochemical and biophysical (SPR) assays. Further optimization led to the discovery of the benzylidenebarbituric acid derivative 7h (EML425) as a potent and selective reversible inhibitor of CBP/p300, noncompetitive versus both acetyl-CoA and a histone H3 peptide, and endowed with good cell permeability.

Transient Ca2+ depletion from the endoplasmic reticulum is critical for skeletal myoblast differentiation.

Endoplasmic reticulum (ER) stress is a cellular condition in which unfolded proteins accumulate in the ER because of various but specific causes. Physiologic ER stress occurs transiently during myoblast differentiation, and although its cause remains unknown, it plays a critical role in myofiber formation. To examine the mechanism underlying ER stress, we monitored ER morphology during differentiation of murine myoblasts.

Identification of the specific interactors of the human lariat RNA debranching enzyme 1 protein.

In eukaryotes, pre-mRNA splicing is an essential step for gene expression. We have been analyzing post-splicing intron turnover steps in higher eukaryotes. Here, we report protein interaction between human Debranching enzyme 1 (hDbr1) and several factors found in the Intron Large (IL) complex, which is an intermediate complex of the intron degradation pathway.

Direct identification of human cellular microRNAs by nanoflow liquid chromatography-high-resolution tandem mass spectrometry and database searching.

MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene networks and participate in many physiological and pathological pathways. To date, miRNAs have been characterized mostly by genetic technologies, which have the advantages of being very sensitive and using high-throughput instrumentation; however, these techniques cannot identify most post-transcriptional modifications of miRNAs that would affect their functions. Herein, we report an analytical system for the direct identification of miRNAs that incorporates nanoflow liquid chromatography-high-resolution tandem mass spectrometry and RNA-sequence database searching.

Bicyclic tetrapeptide histone deacetylase inhibitors with methoxymethyl ketone and boronic acid zinc-binding groups.

Histone deacetylase (HDAC) inhibitors are a class of potential therapeutics for the treatment of cancer. Bicyclic tetrapeptides equipped with methoxymethyl ketone and boronic acid as zinc-binding group were designed and synthesized. The inhibitory activities of these compounds were evaluated against HDAC enzymes.

Anatomical landmarks for registration of experimental image data to volumetric rodent brain atlasing templates.

Background: Assignment of anatomical reference is a key step in integration of the rapidly expanding collection of rodent brain data. Landmark-based registration facilitates spatial anchoring of diverse types of data not suitable for automated methods operating on voxel-based image information.

New Tool: Here we propose a standardized set of anatomical landmarks for registration of whole brain imaging datasets from the mouse and rat brain, and in particular for integration of experimental image data in Waxholm Space (WHS).

FTO-dependent demethylation of N6-methyladenosine regulates mRNA splicing and is required for adipogenesis.

The role of Fat Mass and Obesity-associated protein (FTO) and its substrate N6-methyladenosine (m6A) in mRNA processing and adipogenesis remains largely unknown. We show that FTO expression and m6A levels are inversely correlated during adipogenesis. FTO depletion blocks differentiation and only catalytically active FTO restores adipogenesis.

RNA cytidine acetyltransferase of small-subunit ribosomal RNA: identification of acetylation sites and the responsible acetyltransferase in fission yeast, Schizosaccharomyces pombe.

The eukaryotic small-subunit (SSU) ribosomal RNA (rRNA) has two evolutionarily conserved acetylcytidines. However, the acetylation sites and the acetyltransferase responsible for the acetylation have not been identified. We performed a comprehensive MS-based analysis covering the entire sequence of the fission yeast, Schizosaccharomyces pombe, SSU rRNA and identified two acetylcytidines at positions 1297 and 1815 in the 3' half of the rRNA.

Spin-orbit coupling induced semi-metallic state in the 1/3 hole-doped hyper-kagome Na3Ir3O8.

The complex iridium oxide Na3Ir3O8 with a B-site ordered spinel structure was synthesized in single crystalline form, where the chiral hyper-kagome lattice of Ir ions, as observed in the spin-liquid candidate Na4Ir3O8, was identified. The average valence of Ir is 4.33+ and, therefore, Na3Ir3O8 can be viewed as a doped analogue of the hyper-kagome spin liquid with Ir(4+).