Marine sponge cyclic peptide theonellamide A disrupts lipid bilayer integrity without forming distinct membrane pores.

Theonellamides (TNMs) are antifungal and cytotoxic bicyclic dodecapeptides derived from the marine sponge Theonella sp. These peptides specifically bind to 3β-hydroxysterols, resulting in 1,3-β-D-glucan overproduction and membrane damage in yeasts. The inclusion of cholesterol or ergosterol in phosphatidylcholine membranes significantly enhanced the membrane affinity of theonellamide A (TNM-A) because of its direct interaction with 3β-hydroxyl groups of sterols.

Photochemical H2 evolution from water catalyzed by a dichloro(diphenylbipyridine)platinum(ii) derivative tethered to multiple viologen acceptors.

A new single-component photocatalyst for the reduction of water to H2, a dichloro(dpbpy)platinum(ii) derivative (dpbpy = 4,4'-diphenyl-2,2'-bipyridine) tethered to four pendant viologen acceptors (1), is shown to exhibit twice higher photocatalytic efficiency than the previously reported dichloro(bpy)-platinum(ii) analog (; bpy = 2,2'-bipyridine), consistent with the higher absorptivity of at the metal-to-ligand charge transfer ((1)MLCT) band due to the larger π-conjugation in dpbpy relative to bpy.

Self-regulated oscillation of transport and topology of magnetic islands in toroidal plasmas.

The coupling between the transport and magnetic topology is an important issue because the structure of magnetic islands, embedded in a toroidal equilibrium field, depends on the nature of the transport at the edge of the islands. Measurements of modulated heat pulse propagation in the DIII-D tokamak have revealed the existence of self-regulated oscillations in the radial energy transport into magnetic islands that are indicative of bifurcations in the island structure and transport near the q = 2 surface. Large amplitude heat pulses are seen in one state followed by small amplitude pulses later in the discharge resulting in a repeating cycle of island states.

VID22 is required for transcriptional activation of the PSD2 gene in the yeast Saccharomyces cerevisiae.

Phosphatidylethanolamine (PE) in the yeast Saccharomyces cerevisiae is synthesized through decarboxylation of phosphatidylserine (PS), catalysed by PS decarboxylase 1 (Psd1p) and 2 (Psd2p) and the cytidine 5'-diphosphate (CDP)-ethanolamine (CDP-Etn) pathway. PSD1 null (psd1Δ) and PSD2 null (psd2Δ) mutants are viable in a synthetic minimal medium, but a psd1Δ psd2Δ double mutant exhibits Etn auxotrophy, which is incorporated into PE through the CDP-Etn pathway. We have previously shown that psd1Δ is synthetic lethal with deletion of VID22 (vid22Δ) [Kuroda et al.

COX assembly factor ccdc56 regulates mitochondrial morphology by affecting mitochondrial recruitment of Drp1.

Mitochondria are dynamic organelles that alter their morphology in response to cellular signaling and differentiation through balanced fusion and fission. In this study, we found that the mitochondrial inner membrane ATPase ATAD3A interacted with ccdc56/MITRAC12/COA3, a subunit of the cytochrome oxidase (COX)-assembly complex. Overproduction of ccdc56 in HeLa cells resulted in fragmented mitochondrial morphology, while mitochondria were highly elongated in ccdc56-repressed cells by the defective recruitment of the fission factor Drp1.

Pt(II)-Catalyzed photosynthesis for H2 evolution cycling between singly and triply reduced species.

A PtCl2(bpy) derivative tethered to two viologen (MV(2+)) moieties drives photochemical H2 evolution via forming a three-electron-reduced species possessing a bpy(-)Ë™-based (or MV(0)-based) reducing equivalent. Such species can only form after one electron reduction of both the MV(2+) sites because of rapid intramolecular electron transfer from bpy(-)Ë™ to MV(2+).

Lipophilic ruthenium salen complexes: incorporation into liposome bilayers and photoinduced release of nitric oxide.

A new lipophilic Ru salen complex with cholesterol groups can be efficiently incorporated into liposome bilayers, allowing the photoinduced release of nitric oxide (NO) and the membrane transport of NO to coexisting liposomes.

Orientation and Order of the Amide Group of Sphingomyelin in Bilayers Determined by Solid-State NMR.

Sphingomyelin (SM) and cholesterol (Chol) are considered essential for the formation of lipid rafts; however, the types of molecular interactions involved in this process, such as intermolecular hydrogen bonding, are not well understood. Since, unlike other phospholipids, SM is characterized by the presence of an amide group, it is essential to determine the orientation of the amide and its order in the lipid bilayers to understand the nature of the hydrogen bonds in lipid rafts. For this study, 1'-(13)C-2-(15)N-labeled and 2'-(13)C-2-(15)N-labeled SMs were prepared, and the rotational-axis direction and order parameters of the SM amide in bilayers were determined based on (13)C and (15)N chemical-shift anisotropies and intramolecular (13)C-(15)N dipole coupling constants.

Deuterium NMR of raft model membranes reveals domain-specific order profiles and compositional distribution.

In this report, we applied site-specifically deuterated N-stearoylsphingomyelins (SSMs) to raft-exhibiting ternary mixtures containing SSM, 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), and cholesterol (Chol) and successfully acquired deuterium quadrupole coupling profiles of SSM from liquid-ordered (Lo) and liquid-disordered (Ld) domains. To our knowledge, this is the first report that shows detailed lipid chain dynamics separately and simultaneously obtained from coexisting Lo and Ld domains. We also found that the quadrupole profile of the Lo phase in the ternary system was almost identical to that in the SSM-Chol binary mixture, suggesting that the order profile of the binary system is essentially applicable to more complicated membrane systems in terms of the acyl chain order.

Regulation of a cerium(IV)-driven Oâ‚‚ evolution reaction using composites of liposome and lipophilic ruthenium complexes.

A composite containing a liposome and a lipophilic ruthenium complex was synthesized to regulate an O2 evolution reaction using cerium(IV) ammonium nitrate as an oxidizing reagent. We found that the surrounding environment of the reaction centre is an important factor for controlling the O2 evolution catalytic reaction. We successfully regulated the reaction activity using the linker length of the lipophilic ligand and using the head groups of the phospholipid component.

A tricarboxylated PtCl(terpyridine) derivative exhibiting pH-dependent photocatalytic activity for Hâ‚‚ evolution from water.

The first negatively charged PtCl(tpy) (tpy = 2,2':6',2''-terpyridine) derivative, formulated as Na2[PtCl(tctpy)]·5H2O (tctpy = 2,2':6',2''-terpyridine-4,4',4''-tricarboxylate), was prepared, characterized, and investigated in detail for its activity as a single-component photocatalyst that drives water reduction to H2 in the presence of a sacrificial electron donor (EDTA). This compound was confirmed to exist in its fully deprotonated form [PtCl(tctpy)](2-) in aqueous media at pH > 4.4.

Catalytic asymmetric hydrogenation of quinoline carbocycles: unusual chemoselectivity in the hydrogenation of quinolines.

The reduction of quinolines selectively took place on their carbocyclic rings to give 5,6,7,8-tetrahydroquinolines, when the hydrogenation was conducted in the presence of a Ru(η(3)-methallyl)2(cod)-PhTRAP catalyst. The chiral ruthenium catalyst converted 8-substituted quinolines into chiral 5,6,7,8-tetrahydroquinolines with up to 91 : 9 er.

Non-classical gluconeogenesis-dependent glucose metabolism in Rhipicephalus microplus embryonic cell line BME26.

In this work we evaluated several genes involved in gluconeogenesis, glycolysis and glycogen metabolism, the major pathways for carbohydrate catabolism and anabolism, in the BME26 Rhipicephalus microplus embryonic cell line. Genetic and catalytic control of the genes and enzymes associated with these pathways are modulated by alterations in energy resource availability (primarily glucose). BME26 cells in media were investigated using three different glucose concentrations, and changes in the transcription levels of target genes in response to carbohydrate utilization were assessed.

Voltammetric study of the boric acid-salicylaldehyde-H-acid ternary system and its application to the voltammetric determination of boron.

The ternary system of boric acid, salicylaldehyde (SA) and H-acid (HA) was voltammetrically studied from kinetic and equilibrium points of view. The effect of the SA substituents was also studied by using two analogs, 5-fluorosalicylaldehyde (F-SA) and 5-methylsalicylaldehyde (Me-SA). The three cathodic peaks of Azomethine H (AzH), Azomethine H-boric acid complex (AzB), and free SA were observed in the solution containing boric acid, SA and HA.

Catalytic asymmetric hydrogenation of pyrimidines.

The asymmetric hydrogenation of pyrimidines proceeded with high enantioselectivity (up to 99% ee) using an iridium catalyst composed of [IrCl(cod)]2, a ferrocene-containing chiral diphosphine ligand (Josiphos), iodine, and Yb(OTf)3 (cod = 1,5-cyclooctadiene). The chiral catalyst converted various 4-substituted pyrimidines into chiral 1,4,5,6-tetrahydropyrimidines in high yield. The lanthanide triflate is crucial for achieving the high enantioselectivity as well as for activating the heteroarene substrate.

Adaptive array technique for differential-phase reflectometry in QUEST.

A Phased Array Antenna (PAA) was considered as launching and receiving antennae in reflectometry to attain good directivity in its applied microwave range. A well-focused beam was obtained in a launching antenna application, and differential-phase evolution was properly measured by using a metal reflector plate in the proof-of-principle experiment at low power test facilities. Differential-phase evolution was also evaluated by using the PAA in the Q-shu University Experiment with Steady State Spherical Tokamak (QUEST).

Progress in base-metal water oxidation catalysis.

This minireview provides a brief overview of the progress that has been made in developing homogeneous water oxidation catalysts based on base metals (manganese, iron, cobalt, nickel, and copper) from the 1990s to mid-2014. The impact of each contribution is analyzed, and opportunities for further improvement are noted. In addition, the relative stabilities of the base-metal catalysts that have been reported are compared to illustrate the importance of developing more robust catalytic systems by using these metals.

A cobalt-NHC complex as an improved catalyst for photochemical hydrogen evolution from water.

A macrocyclic N-heterocyclic carbene (NHC)-cobalt complex was found to act as an improved H2-evolving catalyst in a [Ru(bpy)3](2+)-sensitized photosystem using methylviologen as a redox acceptor (MV(2+) + e(-) → MV(+)˙, MV(2+) = N,N'-dimethyl-4,4'-bipyridinium), which provides a driving force of only 150 meV for H2 evolution at pH 5.0.

Mechanism of water oxidation by non-heme iron catalysts when driven with sodium periodate.

Iron tris(2-methylpyridyl)amine (TPA) and iron 1-(bis(2-methylpyridyl)amino)-2-methyl-2-propanoate (BPyA) salts are characterized as water oxidation catalysts (WOCs) using sodium periodate. Under the conditions used, these complexes serve as homogeneous WOCs as demonstrated via kinetic analysis and dynamic light scattering (DLS). The Fe(BPyA) salt serves as both a mononuclear and dinuclear catalyst, with the mononuclear form showing higher catalytic activity.

Weak hydrogen bonding motifs of ethylamino neurotransmitter radical cations in a hydrophobic environment: infrared spectra of tryptamine(+)-(N2)n clusters (n ≤ 6).

Size-selected clusters of the tryptamine cation with N2 ligands, TRA(+)-(N2)n with n = 1-6, are investigated by infrared photodissociation (IRPD) spectroscopy in the hydride stretch range and quantum chemical calculations at the ωB97X-D/cc-pVTZ level to characterize the microsolvation of this prototypical aromatic ethylamino neurotransmitter radical cation in a nonpolar solvent. Two types of structural isomers exhibiting different interaction motifs are identified for the TRA(+)-N2 dimer, namely the TRA(+)-N2(H) global minimum, in which N2 forms a linear hydrogen bond (H-bond) to the indolic NH group, and the less stable TRA(+)-N2(π) local minima, in which N2 binds to the aromatic π electron system of the indolic pyrrole ring. The IRPD spectrum of TRA(+)-(N2)2 is consistent with contributions from two structural H-bound isomers with similar calculated stabilization energies.

Mechanistic studies of photoinduced intramolecular and intermolecular electron transfer processes in RuPt-centred photo-hydrogen-evolving molecular devices.

The photoinduced electron transfer properties of two photo-hydrogen-evolving molecular devices (PHEMDs) [(bpy)2Ru(II)(phen-NHCO-bpy-R)Pt(II)Cl2](2+) (i.e., condensation products of [Ru(bpy)2(5-amino-phen)](2+) and (4-carboxy-4′-R-bpy)PtCl2; bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline; RuPt-COOH for R = COOH and RuPt-CN for R = CN) were investigated.

New insight into the structure, reaction mechanism, and biological functions of neutral ceramidase.

Ceramidase (CDase) is an enzyme that hydrolyzes the N-acyl linkage between the sphingoid base and fatty acid of ceramide. These enzymes are classified into three distinct groups, acid (Asah1), neutral (Asah2), and alkaline (Asah3) CDases, based on their primary structure and optimum pH. Acid CDase catabolizes ceramide in lysosomes and is found only in vertebrates.

Line tension of alkane lenses on aqueous surfactant solutions at phase transitions of coexisting interfaces.

Alkane droplets on aqueous solutions of surfactants exhibit a first-order wetting transition as the concentration of surfactant is increased. The low-concentration or "partial wetting" state corresponds to an oil lens in equilibrium with a two-dimensional dilute gas of oil and surfactant molecules. The high-concentration or "pseudo-partial wetting" state consists of an oil lens in equilibrium with a mixed monolayer of surfactant and oil.

Guest responsivity of a two-dimensional coordination polymer incorporating a cholesterol-based co-ligand.

To implement specific guest responsivity, a hydrophobic cholesterol-based co-ligand, cholest-5-en-3-yl-4-isonicotinate (Cholpy), was incorporated into a two-dimensional Hofmann-type Co(II)Ni(II) coordination polymer. The chemically programmed structure successfully demonstrated the unique guest response with remarkable chromatic changes.

An endocrine disruptor, bisphenol A, affects development in the protochordate Ciona intestinalis: hatching rates and swimming behavior alter in a dose-dependent manner.

Bisphenol A (BPA) is widely used industrially to produce polycarbonate plastics and epoxy resins. Numerous studies document the harmful effects caused by low-dose BPA exposure especially on nervous systems and behavior in experimental animals such as mice and rats. Here, we exposed embryos of a model chordate, Ciona intestinalis, to seawater containing BPA to evaluate adverse effects on embryonic development and on the swimming behavior of subsequent larvae.