Feeder cells support the culture of induced pluripotent stem cells even after chemical fixation.

Chemically fixed mouse embryonic fibroblasts (MEFs), instead of live feeder cells, were applied to the maintenance of mouse induced pluripotent stem (miPS) cells. Formaldehyde and glutaraldehyde were used for chemical fixation. The chemically fixed MEF feeders maintained the pluripotency of miPS cells, as well as their undifferentiated state.

Synthesis of dumbbell-shaped cyclic RNAs for RNA interference.

RNA interference (RNAi) is a potent and highly specific gene-silencing phenomenon that was first reported for the nematode Caenorhabditis elegans. It has been discovered that genes could be silenced by introducing double-stranded RNAs (dsRNAs) complementary to the messenger RNA sequences. Since then, RNAi has been shown as an evolutionarily well-conserved process that plays an important role in host defense and in regulation of gene expression.

Structural characterization of nanoparticles from thermoresponsive poly(N-isopropylacrylamide)-DNA conjugate.

Poly(N-isopropylacrylamide) (PNIPAAm) grafted with single-stranded (ss) DNA conjugate (PNIPAAm-g-DNA) self-assembles above its lower critical solution temperature to form colloidal particles. When the ssDNA within the particle hybridizes with its complementary DNA, the particles aggregate above a certain threshold of salt concentration with drastically increased turbidity in solution. Detailed structural information of the particle was obtained mainly by small-angle X-ray scattering.

Integrated approach toward the discovery of glyco-biomarkers of inflammation-related diseases.

Glycobiology has contributed tremendously to the discovery and characterization of cancer-related biomarkers containing glycans (i.e., glyco-biomarkers) and a more detailed understanding of cancer biology.

Oligonucleotide-templated reactions for sensing nucleic acids.

Oligonucleotide-templated reactions are useful for applying nucleic acid sensing. Various chemistries for oligonucleotide-templated reaction have been reported so far. Major scientific interests are focused on the development of signal amplification systems and signal generation systems.

A role for sphingomyelin-rich lipid domains in the accumulation of phosphatidylinositol-4,5-bisphosphate to the cleavage furrow during cytokinesis.

Cytokinesis is a crucial step in the creation of two daughter cells by the formation and ingression of the cleavage furrow. Here, we show that sphingomyelin (SM), one of the major sphingolipids in mammalian cells, is required for the localization of phosphatidylinositol-4,5-bisphosphate (PIP(2)) to the cleavage furrow during cytokinesis. Real-time observation with a labeled SM-specific protein, lysenin, revealed that SM is concentrated in the outer leaflet of the furrow at the time of cytokinesis.

Two-dimensional superstructure formation of fluorinated fullerene on Au(111): a scanning tunneling microscopy study.

A two-dimensional fluorinated fullerene (C(60)F(36)) superstructure has been successfully formed on Au(111) and was investigated using scanning tunneling microscopy (STM) and density functional theory calculations. Although there exist three isomers (C(3), C(1), and T) in our molecular source, STM images of the molecules in the well-ordered region all appear identical, with 3-fold symmetry. This observation together with the differences in the calculated lowest unoccupied molecular orbital (LUMO) distribution among the three isomers suggests that a well-ordered monolayer consists of only the C(3) isomer.

Regulation of transglutaminase-mediated hepatic cell death in alcoholic steatohepatitis and non-alcoholic steatohepatitis.

Background And Aim: Transglutaminase 2 (TG2), catalyzing crosslinking between lysine and glutamine residues, is involved in many liver diseases. We previously reported that TG2, induced in the nucleus of ethanol- or free fatty acids (FFAs)-treated hepatic cells, crosslinks and inactivates a transcription factor Sp1, leading to reduced expression of c-Met and thereby caspase independent hepatic apoptosis in culture systems, animal models, and both alcoholic steatohepatitis (ASH) and non-alcoholic steatohepatitis (NASH) patients. FFAs increase endoplasmic reticulum (ER) stress, NFkB activation and nuclear TG2 (nTG2) through pancreatic ER kinase (PERK)-dependent pathway, whereas ethanol induces nTG2 via retinoid signaling.

Analysis of glycoprotein processing in the endoplasmic reticulum using synthetic oligosaccharides.

Protein quality control (QC) in the endoplasmic reticulum (ER) comprises many steps, including folding and transport of nascent proteins as well as degradation of misfolded proteins. Recent studies have revealed that high-mannose-type glycans play a pivotal role in the QC process. To gain knowledge about the molecular basis of this process with well-defined homogeneous compounds, we achieved a convergent synthesis of high-mannose-type glycans and their functionalized derivatives.

Emergent phenomena at oxide interfaces.

Recent technical advances in the atomic-scale synthesis of oxide heterostructures have provided a fertile new ground for creating novel states at their interfaces. Different symmetry constraints can be used to design structures exhibiting phenomena not found in the bulk constituents. A characteristic feature is the reconstruction of the charge, spin and orbital states at interfaces on the nanometre scale.

Self-assembled poly(imidazole-palladium): highly active, reusable catalyst at parts per million to parts per billion levels.

Metalloenzymes are essential proteins with vital activity that promote high-efficiency enzymatic reactions. To ensure catalytic activity, stability, and reusability for safe, nontoxic, sustainable chemistry, and green organic synthesis, it is important to develop metalloenzyme-inspired polymer-supported metal catalysts. Here, we present a highly active, reusable, self-assembled catalyst of poly(imidazole-acrylamide) and palladium species inspired by metalloenzymes and apply our convolution methodology to the preparation of polymeric metal catalysts.

Overproduction of anti-Tn antibody MLS128 single-chain Fv fragment in Escherichia coli cytoplasm using a novel pCold-PDI vector.

Overproduction of recombinant proteins in Escherichia coli is often hampered by their failure to fold correctly, leading to their accumulation within inclusion bodies. To overcome the problem, a variety of techniques aimed at soluble expression have been developed including low temperature expression and/or fusion of soluble tags and chaperones. However, a general protocol for bacterial expression of disulfide bond-containing proteins has hitherto not been established.

Development of polymeric palladium-nanoparticle membrane-installed microflow devices and their application in hydrodehalogenation.

We have developed a variety of polymeric palladium-nanoparticle membrane-installed microflow devices. Three types of polymers were convoluted with palladium salts under laminar flow conditions in a microflow reactor to form polymeric palladium membranes at the laminar flow interface. These membranes were reduced with aqueous sodium formate or heat to create microflow devices that contain polymeric palladium-nanoparticle membranes.

Bis-cyclometalated iridium(III) complexes bearing ancillary guanidinate ligands. Synthesis, structure, and highly efficient electroluminescence.

We report the synthesis, structure, and photophysical and electroluminescent (EL) properties of a series of heteroleptic bis(pyridylphenyl)iridium(III) complexes with various ancillary guanidinate ligands. The reaction of the bis(pyridylphenyl)iridium(III) chloride [(ppy)(2)Ir(μ-Cl)](2) with the lithium salt of various guanidine ligands Li{(N(i)Pr)(2)C(NR(1)R(2))} at 80 °C gave in 60-80% yield the corresponding heteroleptic bis(pyridylphenyl)/guanidinate iridium(III) complexes having a general formula of [(ppy)(2)Ir{(N(i)Pr)(2)C(NR(1)R(2))}], where NR(1)R(2) = NPh(2) (1), N(C(6)H(4)(t)Bu-4)(2) (2), carbazolyl (3), 3,6-bis(tert-butyl)carbazolyl (4), N(C(6)H(4))(2)S (5), N(C(6)H(4))(2)O (6), indolyl (7), NEt(2) (8), N(i)Pr(2) (9), N(i)Bu(2) (10), and N(SiMe(3))(2) (11). These heteroleptic cyclometalated (C^N) iridium(III) complexes showed intense absorption bands in the UV region assignable to π-π* transitions and weaker metal-to-ligand charge-transfer transitions extending to the visible region.

[Development of novel types of biologically active compounds based on natural products and biomolecules].

Enzyme inhibitors have been utilized as useful tools for elucidating the function and structure of specific enzymes and for cell biology studies. Recently, chemical screening from natural sources and compound libraries has led to the rapid discovery of enzyme inhibitors. To create more useful inhibitors with high enzyme selectivity, and molecular probes for analyzing the precise mode of actions for enzymes, synthetic approaches based on natural products and bio-molecules are considered to have an important role in medicinal chemistry and chemical biology.

Oligoethylene-glycol-functionalized polyoxythiophenes for cell engineering: syntheses, characterizations, and cell compatibilities.

A series of methyl- or benzyl-capped oligoethylene glycol functionalized 2,5-dibromo-3-oxythiophenes are synthesized and successfully polymerized by either Grignard metathesis (GRIM) polymerization or reductive coupling polymerization to yield the corresponding polymers in reasonable yields and molecular weights with narrow molecular weight distribution. These synthesized polyoxythiophenes exhibit high electroactivity and stability in aqueous solution when a potential is applied. Polyoxythiophenes from different polymerization approaches display different colors after purification and spectroelectrochemical studies confirm that the difference of color is from the difference of doping state.

Solid-state NMR analysis of calcium and d-mannose binding of BMY-28864, a water-soluble analogue of pradimicin A.

Pradimicin A (PRM-A) is a unique antibiotic with a lectin-like ability to recognize d-mannopyranosides (Man) in the presence of Ca(2+) ion. BMY-28864 (1) is a water-soluble analogue of PRM-A, which has been extensively used for studies on the mode of Man recognition and antifungal action of pradimicins. Although it has been assumed that PRM-A and 1 bind Man in a similar fashion, direct experimental evidence has yet to be provided.

Branched N-glycans and their implications for cell adhesion, signaling and clinical applications for cancer biomarkers and in therapeutics.

Branched N-glycans are produced by a series of glycosyltransferases including N-acetylglucosaminyltransferases and fucosyltransferases and their corresponding genes. Glycans on specific glycoproteins, which are attached via the action of glycosyltransferases, play key roles in cell adhesion and signaling. Examples of this are adhesion molecules or signaling molecules such as integrin and E-cadherin, as well as membrane receptors such as the EGF and TGFβ receptors.

Spirotoamides A and B, novel 6,6-spiroacetal polyketides isolated from a microbial metabolite fraction library.

Two new 6,6-spiroacetal polyketides, spirotoamides A (1) and B (2), were isolated from a microbial metabolite fraction library of Streptomyces griseochromogenes JC82-1223 by screening of structurally unique compounds based on a search of spectral database. The fraction library was constructed using a systematic separation method to efficiently discover new metabolites from microbial sources such as actinomycetes and fungi. The structures of 1 and 2 were elucidated by 2D-NMR and mass spectrometric measurements.

Heterologous gene expression by chromosomal integration in fission yeast.

Thanks to the convenience and flexibility of the multicopy plasmid-based approach for heterologous gene expression, this technique has long been used for biological studies, especially in prokaryotes and lower eukaryotes. For better understanding of biological mechanisms, however, there are increasing demands on the experimental technologies enabling fine-tuned expression of introduced heterologous genes or serving conditions that are closer to the physiological conditions. For this purpose, the use of direct tagging of a chromosomal gene has been gradually increasing, although the use conditions of this approach are relatively limited compared to plasmid-based methods.

In vitro mannose trimming property of human ER α-1,2 mannosidase I.

Endoplasmic reticulum α-1,2 mannosidase I (ERManI) is an enzyme, which removes α(1-2) linked mannoses from asparagine-linked oligosaccharides on glycoproteins in the endoplasmic reticulum (ER). ERManI preferentially removes one α(1-2) linked mannose from B-chain of Man(9)GlcNAc(2). When glycoproteins fail to achieve properly folding, increased removal of α(1-2) linked mannoses on their oligosaccharides is induced and leads them to be disposed and degraded by ER-associated degradation pathway.

The first observation of electroluminescence from di(2-naphthyl)disilene, an Si=Si double bond-containing π-conjugated compound.

Air-stable, room-temperature emissive di(2-naphthyl)disilene, protected by the bulky 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl (Eind) groups, can emit light in an organic light-emitting diode, thus providing the first experimental demonstration of electroluminescence from the heavy group 14 unsaturated compounds.