Infrared spectroscopic and computational studies of Co(ClO) dissolved in N,N-dimethylformamide (DMF). Vibrations of DMF influenced by Co or ClO or both.

Infrared (IR) spectroscopy for N,N-dimethylformamide (DMF) shows that the OCN bend (δ) and the CO stretch (ν) vibrations undergo an upshift and a downshift, respectively, on the dissolution of Co(ClO). Quantum chemical calculations are performed for optimizing the structures and predicting the IR spectra of model complexes for solute species. The calculations reveal that Co exerts a much larger influence than ClO on the vibrations of DMF.

Vapor switching of the luminescence mechanism in a Re(V) complex.

A ReV complex demonstrates methanol selective luminescent color changes from red to green together with enhancements of the corresponding luminescence quantum yields twenty-three times. These characteristic responses are caused by the switching of the characters of the emissive states from metal-to-ligand charge transfer to d-d transition along with a single-crystal-to-single-crystal ligand exchange reaction.

Assembly formation of minor dihydrosphingomyelin in sphingomyelin-rich ordered membrane domains.

The lipidome of mammalian cells not only contain sphingomyelin (SM) but also, as a minor component, dihydrosphongomyelin (DHSM), in which the double bond at C4-C5 in the sphingosine base is reduced to a single-bond linkage. It has been indicated that DHSM forms ordered domains more effectively than SM due to its greater potential to induce intermolecular hydrogen bonds. However, direct information on partition and dynamic behaviors of DHSM in raft-like liquid-ordered (L) and non-raft-like liquid-disordered (L) phase-segregated membranes has been lacking.

Proper regulation of inositolphosphorylceramide levels is required for acquirement of low pH resistance in budding yeast.

All organisms have stress response systems to protect themselves from various environmental stresses, and regulation of membrane lipids is thought to play an important role in acquirement of stress tolerance. Complex sphingolipids in the yeast Saccharomyces cerevisiae are classified into three types based on differences in the structure of the polar head group, and the compositions and quantities of complex sphingolipids in biomembranes are tightly regulated. In this study, we found that the accumulation of inositol phosphorylceramides (IPCs) due to a defect of mannosylinositol phosphorylceramide biosynthesis (sur1∆ csh1∆), i.

Luminescent ionic liquid formed from a melted rhenium(v) cluster.

Recently, non-crystalline coordination materials have been shown to represent a versatile class of functional materials. However, such materials incorporating metal complex clusters have remained largely unexplored. Herein, we demonstrate that a luminescent tetranuclear ReV cluster melts at 489 K, with the cluster structure being maintained in the corresponding supercooled ionic liquid phase.

The influence of ceramide and its dihydro analog on the physico-chemical properties of sphingomyelin bilayers.

The influence of ceramide and its dihydro analog (Cer and DHCer, respectively; inclusively termed Cers) on sphingomyelin (SM) bilayers was examined. Fluorescent microscopy showed that SM/Cers binary bilayers undergo phase separation between Cers-rich and Cers-poor phases. Based on calorimetry, the content of Cers in the Cers-rich phase was estimated and the results show that DHCer in the DHCer-rich phase (17.

Effects of Water Addition on a Catalytic Fluorination of Dienamine.

We investigate the effects of water addition on a highly stereocontrolled fluorination of dienamine generated by α-branched enals and 6'-hydroxy-9-amino-9-deoxy--quinidine with -fluorobenzenesulfonimide (NFSI) in the presence of Brønsted acid both experimentally and theoretically. It is experimentally found that water addition to organic solvent significantly shortens the reaction time whereas excessive water addition decreases the enantiomeric excess. The results calculated with three-dimensional reference interaction site model self-consistent field (3D-RISM-SCF) method are in good agreement with the experimental ones.

Discovery of novel oestrogen receptor α agonists and antagonists by screening a revisited privileged structure moiety for nuclear receptors.

Bisphenol A (BPA) is used as an industrial raw material for polycarbonate plastics and epoxy resins; however, various concerns have been reported regarding its status as an endocrine-disrupting chemical. BPA interacts not only with oestrogen receptors (ERs) but constitutive androstane receptor, pregnane X receptor, and oestrogen-related receptor γ (ERRγ); therefore, the bisphenol structure represents a privileged structure for the nuclear-receptor superfamily. Here, we screen 127 BPA-related compounds by competitive-binding assay using [H]oestradiol and find that 20 compounds bind to ERα with high affinity.

An earth-abundant system for light-driven CO reduction to CO using a pyridinophane iron catalyst.

Herein we report an earth-abundant photocatalytic system for CO2 reduction to CO based on an iron catalyst combined with a CuI photosensitizer. Under visible light irradiation CO is produced as the main product (TONCO = 565, TOFmaxCO = 114 h-1) with a high selectivity over H2 production (SelCO2 = 84%).

Mechanism of local anesthetic-induced disruption of raft-like ordered membrane domains.

Background: Because ordered membrane domains, called lipid rafts, regulate activation of ion channels related to the nerve pulse, lipids rafts are thought to be a possible target for anesthetic molecules. To understand the mechanism of anesthetic action, we examined influence of representative local anesthetics (LAs); dibucaine, tetracaine, and lidocaine, on raft-like liquid-ordered (L)/non-raft-like liquid-disordered (L) phase separation.

Methods: Impact of LAs on the phase separation was observed by fluorescent microscopy.

A new and practical Se(IV) removal method using Fe type cation exchange resin.

An effective method for removing selenium (Se) from water is required from the viewpoint of environmental preservation. To establish this method, a cation exchange resin that adsorbed ferric ions was applied as an adsorbent. In this study, the adsorption behavior of Se to the adsorbent was examined by both batch and column methods.

A concise method for quantitative analysis of interactions between lipids and membrane proteins.

Although interactions between lipids and membrane proteins (MPs) have been considered crucially important for understanding the functions of lipids, lack of useful and convincing experimental methods has hampered the analysis of the interactions. Here, we developed a surface plasmon resonance (SPR)-based concise method for quantitative analysis of lipid-MP interactions, coating the sensor chip surface with self-assembled monolayer (SAM) with C-chain. To develop this method, we used bacteriorhodopsin (bR) as an MP, and examined its interaction with various types of lipids.

Temperature Dependence of Electrophoretic Mobility and Hydrodynamic Radius of Microgels of Poly(-isopropylacrylamide).

Electrostatic interactions in charged microgels, which are dominated by the microgel net charge, play a crucial role in colloidal stabilization and loading of small, charged molecules. In this study, the temperature dependences of electrophoretic mobility and hydrodynamic radius were measured for a slightly ionized poly(-isopropylacrylamide) (PNIPA) microgel in a dilute suspension. A decrease in was observed in the temperature range between 30 °C and 35 °C, corresponding to the lower critical solution temperature of PNIPA, and an increase in || was observed in a higher temperature range between 34 °C and 37 °C.

Consecutive ligand-based PCET processes affording a doubly reduced nickel pyrazinedithiolate which transforms into a metal hydride required to evolve H.

Our DFT results demonstrate that hydrogen evolution from water catalyzed by a nickel pyradinedithiolate (dcpdt) molecular hydrogen evolution catalyst [NiII(dcpdt)2]2- proceeds via the formation of a square-planar nickel(ii) hydride intermediate which is given by unprecedented structural transformation of a doubly reduced triply protonated species [NiII(dcpdtH2)(dcpdtH)]-, afforded as a result of two consecutive ligand-based reductions of [NiII(dcpdt)(dcpdtH)]- through proton-coupled electron transfer (PCET) pathways.

Freezing of micrometer-sized liquid droplets of pure water evaporatively cooled in a vacuum.

Freezing processes are reported for pure-water droplets generated in a vacuum in the size range of 49-71 μm in diameter. The process is characterized for each size by measurement of a freezing curve, where the fraction of frozen droplets is evaluated as a function of time. The 49 μm droplet was found to freeze at a time between 7.

Selective adsorption of 1,3-dimethyltrisulfane (DMTS) responsible for aged odour in Japanese sake using supported gold nanoparticles.

Gold (Au) nanoparticles (NPs) supported on SiO (Au/SiO) were prepared by a practical impregnation method and applied as an adsorbent for 1,3-dimethyltrisulfane (DMTS), which is responsible for an unpleasant odour in drinks, especially Japanese sake. Compared with a conventional adsorbent, activated carbon, Au/SiO selectively reduced the DMTS concentration in Japanese sake without decreasing the concentrations of other aromatic components. DFT calculations revealed that the selective adsorption of DMTS occurred through the formation of a stable intermediate.

Porin proteins have critical functions in mitochondrial phospholipid metabolism in yeast.

Mitochondrial synthesis of cardiolipin (CL) and phosphatidylethanolamine requires the transport of their precursors, phosphatidic acid and phosphatidylserine, respectively, to the mitochondrial inner membrane. In yeast, the Ups1-Mdm35 and Ups2-Mdm35 complexes transfer phosphatidic acid and phosphatidylserine, respectively, between the mitochondrial outer and inner membranes. Moreover, a Ups1-independent CL accumulation pathway requires several mitochondrial proteins with unknown functions including Mdm31.

An Atomistic Model of a Precursor State of Light-Induced Channel Opening of Channelrhodopsin.

Channelrhodopsins (ChRs) are microbial light-gated ion channels with a retinal chromophore and are widely utilized in optogenetics to precisely control neuronal activity with light. Despite increasing understanding of their structures and photoactivation kinetics, the atomistic mechanism of light gating and ion conduction remains elusive. Here, we present an atomic structural model of a chimeric ChR in a precursor state of the channel opening determined by an accurate hybrid molecular simulation technique and a statistical theory of internal water distribution.

A computational scheme of pK values based on the three-dimensional reference interaction site model self-consistent field theory coupled with the linear fitting correction scheme.

A scheme for quantitatively computing the acid dissociation constant, pKa, of hydrated molecules is proposed. It is based on the three-dimensional reference interaction site model self-consistent field (3D-RISM-SCF) theory coupled with the linear fitting correction (LFC) scheme. In LFC/3D-RISM-SCF, pKa values of target molecules are evaluated using the Gibbs energy difference between the protonated and unprotonated states calculated by 3D-RISM-SCF and the parameters fitted by the LFC scheme to the experimental values of training set systems.

Infrared spectroscopic and computational studies on formamide solutions of Ca. Vibrational frequencies of formamide and modes of coordination to Ca.

Infrared spectroscopy for formamide (FA) solutions of Ca(ClO) shows that both CN stretch (ν) and CO stretch (ν) bands of FA undergo upshifts in the presence of Ca. Modeling of Ca in FA solutions is accomplished by quantum chemical calculations for Ca(FA) (n = 1-8) complexes with Polarizable Continuum Model (PCM). The calculations indicate that bidentate Ca(FA) complexes are not consistent with the observed upshift of the ν band, although a bidentate coordination of four FA molecules via both O and N atoms was assumed in a previous study of the same system.

Evidence of lipid rafts based on the partition and dynamic behavior of sphingomyelins.

Sphingomyelin (SM)-rich membrane nano-domains, called lipid rafts, have attracted the interest of researchers due to their potential involvement in the formation of signaling platform. Although there are many studies on lipid rafts, the direct observation of lipid rafts is still challenging owing to two critical reasons. One is the lack of an appropriate fluorescent probe mimicking the native behavior of raft lipids; fluorescent labeling often alters the intrinsic disposition of raft lipids.