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11923526 | Functional materials based on self-assembly of polymeric supramolecules. | Self-assembly of polymeric supramolecules is a powerful tool for producing functional materials that combine several properties and may respond to external conditions. We illustrate the concept using a comb-shaped architecture. Examples include the hexagonal self-organization of conjugated conducting polymers and the p... |
11923525 | Synthesis beyond the molecule. | Weak, noncovalent interactions between molecules control many biological functions. In chemistry, noncovalent interactions are now exploited for the synthesis in solution of large supramolecular aggregates. The aim of these syntheses is not only the creation of a particular structure, but also the introduction of speci... |
11923524 | Toward self-organization and complex matter. | Beyond molecular chemistry based on the covalent bond, supramolecular chemistry aims at developing highly complex chemical systems from components interacting through noncovalent intermolecular forces. Over the past quarter century, supramolecular chemistry has grown into a major field and has fueled numerous developme... |
11922670 | Comparative thermodynamics for monomer and dimer sequence-dependent binding of a heterocyclic dication in the DNA minor groove. | Phenylamidine cationic groups linked by a furan ring (furamidine) and related symmetric diamidine compounds bind as monomers in the minor groove of AT sequences of DNA. DB293, an unsymmetric derivative with one of the phenyl rings of furamidine replaced with a benzimidazole, can bind to AT sequences as a monomer but bi... |
11922290 | Electrokinetic chromatography utilizing two pseudostationary phases providing ion-exchange and hydrophobic interactions. | The electrokinetic chromatographic separation of a series of inorganic and organic anions was achieved by utilizing an electrolyte system comprising a cationic soluble polymer (poly(diallydimethylammonium chloride, PDDAC) and a neutral beta-cyclodextrin (beta-CD) as pseudostationary phases. The separation mechanism was... |
11919625 | Exchange-biased quantum tunnelling in a supramolecular dimer of single-molecule magnets. | Various present and future specialized applications of magnets require monodisperse, small magnetic particles, and the discovery of molecules that can function as nanoscale magnets was an important development in this regard. These molecules act as single-domain magnetic particles that, below their blocking temperature... |
11918808 | Engineering specificity of starter unit selection by the erythromycin-producing polyketide synthase. | Chain initiation on many modular polyketide synthases is mediated by acyl transfer from the CoA ester of a dicarboxylic acid, followed by decarboxylation in situ by KSQ, a ketosynthase-like decarboxylase domain. Consistent with this, the acyltransferase (AT) domains of all KSQ-containing loading modules are shown here ... |
11920885 | Chiral separation of gemifloxacin in sodium-containing media using chiral crown ether as a chiral selector by capillary and microchip electrophoresis. | Chiral crown ether, (+)-(18-crown-6)-tetracarboxylic acid (18C6H(4)), is an effective chiral selector for resolving enantiomeric primary amines owing to the difference in affinities between 18C6H(4) and each of the amine enantiomers. In addition to the destacking effect of sodium ion in the sample solution, the strong ... |
11920882 | Drug-plasma protein binding assay by electrokinetic chromatography-frontal analysis. | We developed a rapid, microscale and reliable analytical method for binding of drugs to plasma proteins using capillary electrophoresis (CE) with ionic cyclodextrins (CD) combined with frontal analysis. These CDs were used as pseudostationary phases of electrokinetic chromatography (EKC). The CD-modified EKC (CDEKC) ap... |
11920878 | Use of peptide nucleic acid probes for detecting DNA single-base mutations by capillary electrophoresis. | Peptide nucleic acid (PNA) oligomers can be used as probes in pre-gel hybridization experiments, as an alternative to Southern hybridization. In this technique, the PNA probe is hybridized to a cyanine-5 labeled DNA sample denatured at low ionic strength, and the mixture is directly injected for size separation into a ... |
11920872 | Accurately describing weak analyte-additive interactions by capillary electrophoresis. | When modeling analyte-additive interactions in capillary electrophoresis (CE), it is necessary to correct for all changes in the apparent electrophoretic mobility of an analyte that are not due to specific binding. Current models based on dynamic complexation have corrected for bulk viscosity changes in the background ... |
11921230 | Chemically induced contraction and stretching of a linear rotaxane dimer. | Copper(I)-induced assembly of two self-complementary identical units, which consist of a ring that incorporates a 1,10-phenanthroline group attached to a small filament containing a second 1,10-phenanthroline (phen) group, leads quantitatively to a doubly threaded complex. Each copper(I) center is four-coordinate and i... |
11914394 | Cn11, the first example of a scorpion toxin that is a true blocker of Na(+) currents in crayfish neurons. | A novel crustacean toxin (Cn11) was isolated and characterized from the venom of the Mexican scorpion Centruroides noxius Hoffmann. It contains 63 amino acid residues and is stabilized by four disulphide bridges. It is lethal to crustaceans (Cambarellus montezumae), less toxic to insects (crickets) and non-toxic to mam... |
11914183 | Mechanisms involved in the progression of androgen-independent prostate cancers: it is not only the cancer cell's fault. | The acquisition of an androgen-independent phenotype by prostate cancer cells is presently a death sentence for patients. In order to have a realistic chance of changing this outcome, an understanding of what drives the progression to androgen independence is critical. We review here a working hypothesis based on the p... |
11911839 | p53-Independent induction of Fas and apoptosis in leukemic cells by an adenosine derivative, Cl-IB-MECA. | A(3) adenosine receptor (A(3)AR) agonists have been reported to influence cell death and survival. The effects of an A(3)AR agonist, 1-[2-chloro-6-[[(3-iodophenyl)methyl]amino]-9H-purin-9-yl]-1-deoxy-N-methyl-beta-D-ribofuranonamide (Cl-IB-MECA), on apoptosis in two human leukemia cell lines, HL-60 and MOLT-4, were inv... |
11911216 | Facile formation of chiral calixarene analogs incorporating cystine peptide into the macrocyclic ring. | Chiral calixarene analogs incorporating cystine peptide into their macrocyclic ring were easily prepared by the cyclization reactions of bis(chloromethyl)phenol-formaldehyde oligomers with cystine peptides in moderate yields. Circular dichroism (CD) spectra indicated the existence of the transmission of the chirality f... |
11907275 | Dynein supports motility of endoplasmic reticulum in the fungus Ustilago maydis. | The endoplasmic reticulum (ER) of most vertebrate cells is spread out by kinesin-dependent transport along microtubules, whereas studies in Saccharomyces cerevisiae indicated that motility of fungal ER is an actin-based process. However, microtubules are of minor importance for organelle transport in yeast, but they ar... |
11907261 | Genomic analysis of homotypic vacuole fusion. | Yeast vacuoles undergo fission and homotypic fusion, yielding one to three vacuoles per cell at steady state. Defects in vacuole fusion result in vacuole fragmentation. We have screened 4828 yeast strains, each with a deletion of a nonessential gene, for vacuole morphology defects. Fragmented vacuoles were found in str... |
11906971 | The human 5-HT7 serotonin receptor splice variants: constitutive activity and inverse agonist effects. | 1. Using membranes from stably or transiently transfected HEK293 cells cultured in 5-HT-free medium and expressing the recombinant human 5-HT(7) receptor splice variants (h5-HT(7(a)), h5-HT(7(b)) and h5-HT(7(d))), we compared their abilities to constitutively activate adenylyl cyclase (AC). 2. All h5-HT(7) splice varia... |
11906261 | Solid-state NMR investigation of indomethacin-cyclodextrin complexes in PEG 6000 carrier. | Various solid dispersions of alpha-, beta- and gamma-cyclodextrin (CD) in PEG 6000 with and without the addition of 5% w/w indomethacin were prepared by the melting method using the original components. The samples were investigated by solid-state (13)C NMR, and the interactions between the drug and the cyclodextrins w... |
11905047 | [From new molecular science to new supramolecular science with macrocyclic polyamines]. | Exploitation of saturated macrocyclic polyamines has led to the discovery of numerous novel functions and new molecules such as 1) unique proton sponge properties; 2) uptake of biological polyanions; 3) peptide-like metal uptake properties; 4) stabilization of unusual oxidation states of metal ions (e.g., CuIII, NiIII)... |
11904956 | [Exploring high affinity monoclonal antibodies for drug invention]. | Antibodies can have a medicinal role because of their high specificity in molecular recognition. Although monoclonal antibodies specific for an antigen can be obtained relatively easily, it is difficult to acquire ones with high affinity. Recently, antibody engineering using an in vitro evolutionary process has been pu... |
11904414 | Identification by redox proteomics of glutathionylated proteins in oxidatively stressed human T lymphocytes. | Formation of mixed disulfides between glutathione and the cysteines of some proteins (glutathionylation) has been suggested as a mechanism through which protein functions can be regulated by the redox status. The aim of this study was to identify the proteins of T cell blasts that undergo glutathionylation under oxidat... |
11902891 | Supramolecular chirogenesis in zinc porphyrins: equilibria, binding properties, and thermodynamics. | Complexation mechanism, binding properties and thermodynamic parameters of supramolecular chirality induction in the achiral host molecule, syn (face-to-face conformation) ethane-bridged bis(zinc porphyrin), upon interaction with chiral monoamine and monoalcohol guests have been studied by means of the UV-vis, CD, (1)H... |
11902885 | Switching "on" and "off" the expression of chirality in peptide rotaxanes. | The hydrogen-bond-directed synthesis, X-ray crystal structures, and optical properties of the first chiral peptide rotaxanes are reported. Collectively these systems provide the first examples of single molecular species where the expression of chirality in the form of a circular dichroism (CD) response can selectively... |
11902884 | Using equilibrium isotope effects to detect intramolecular OH/OH hydrogen bonds: structural and solvent effects. | A comparative (1)H NMR study of partially deuterated 1,3- and 1,4-diols has demonstrated that intramolecular hydrogen bonds of different geometry can give rise to equilibrium isotope shifts of opposite sign in hydrogen-bond-accepting solvents such as DMSO-d(6), acetone-d(6), and THF-d(8). The sign inversion is interpre... |
11902879 | Nonactin biosynthesis: the initial committed step is the condensation of acetate (malonate) and succinate. | Nonactin is a macrotetrolide antibiotic produced by Streptomyces griseus subsp. griseus ETH A7796 that has shown activity against the P170-glycoprotein efflux pump associated with multiple drug resistant cancer cells. Nonactin is a polyketide, albeit a highly atypical one. The structure is composed of two units of each... |
11902859 | Water-stabilized cavitands. | Tetrabenzimidazole cavitands 4 were prepared by condensation of ortho esters with octaamino cavitand 3 in 70-80% yield. Molecular modeling predicted that no intramolecular hydrogen bonds are possible between the imidazole fragments in the vase conformation of 4. Instead, this conformation provides four perfect binding ... |
11902917 | Development and validation of oxygen radical absorbance capacity assay for lipophilic antioxidants using randomly methylated beta-cyclodextrin as the solubility enhancer. | We recently reported the improved oxygen radical absorbance capacity (ORAC) assay using fluorescein (FL) as the fluorescent probe. The current ORAC(FL) assay is limited in hydrophilic antioxidant due to the aqueous environment of the assay. Lipophilic antioxidants mainly include the vitamin E family and carotenoids, wh... |
11901200 | Epidermal transglutaminase (TGase 3) is the autoantigen of dermatitis herpetiformis. | Gluten sensitivity typically presents as celiac disease, a common chronic small intestinal disorder. However, in certain individuals it is associated with dermatitis herpetiformis, a blistering skin disease characterized by granular IgA deposits in the papillary dermis. While tissue transglutaminase has been implicated... |
11900542 | Molecular features of the copper binding sites in the octarepeat domain of the prion protein. | Recent evidence suggests that the prion protein (PrP) is a copper binding protein. The N-terminal region of human PrP contains four sequential copies of the highly conserved octarepeat sequence PHGGGWGQ spanning residues 60-91. This region selectively binds Cu2+ in vivo. In a previous study using peptide design, EPR, a... |
11896727 | Mechanistic information from pressure acceleration of hydride formation via proton binding to a cobalt(I) macrocycle. | The effect of pressure on proton binding to the racemic isomer of the cobalt(I) macrocycle, CoL(+) (L = 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene), has been studied for a series of proton donors using pulse radiolysis techniques. The second-order rate constants for the reaction of CoL(+) with... |
11896696 | A simultaneous reduction, substitution, and self-assembly reaction under hydrothermal conditions afforded the first diiodopyridine copper(I) coordination polymer. | A simultaneous reduction of copper(II) to copper(I) by pyridinecarboxylate and the substitution of carboxylato groups by iodo nucleophiles in a self-assembly process under hydrothermal conditions afforded a new iodine-inclusion coordination polymer [CuI(C5H3NI2)*1/2I2] 1. The synthetic studies of the substitution proce... |
11895395 | Elongation and contraction of molecular springs. Synthesis, structures, and properties of bridged [7]thiaheterohelicenes. | A series of bridged [7]thiaheterohelicenes 3a-c and 4 with a variety of helical pitches have been prepared from racemic and optical pure 2,13-bis(hydroxymethyl)dithieno[3,2-e:3',2'-e']benzo[1,2-b:4,3-b']bis[1]benzothiophene (1) in order to investigate the helical structures in solution. Recrystallizations of (PM)-3a, (... |
11893508 | Protein recognition by cell surface receptors: physiological receptors versus virus interactions. | Protein-protein recognition is a major kind of receptor-ligand interaction: a living cell receives external signals to adapt to the environment through cell surface receptors. On opposing cell surfaces, such recognition bears distinct features: it is a multivalent, reversible and avidity-driven process. The affinity be... |
11893193 | A concise, modular synthesis of chiral peraza-macrocycles using chiral aziridines. | [reaction: see text] Novel chiral peraza-macrocycles were synthesized from chiral aziridines as a common building block. Efficient syntheses of chiral [26]-N(6), [12]-N(4), [9]-N(3), and [14]-N(4) systems were accomplished. |
11893187 | Cooperative C(60) binding to a porphyrin tetramer arranged around a p-terphenyl axis in 1:2 host-guest stoichiometry. | [structure: see text] Porphyrin tetramer 1 was newly designed and synthesized to construct a novel cooperative [60]fullerene (C(60)) binding system. Compound 1 has a p-terphenyl axis, which is expected to act as a scaffold for a guest-binding information transducer. In toluene, 1 can bind 2 equiv of C(60) to produce a ... |
11893186 | Topological equivalences between organic and coordination polymer crystal structures: an organic ladder formed with three-connected molecular and supramolecular synthons. | [structure: see text] Crystal engineering of an organic ladder can be achieved with a T-shaped molecule, 4,4-bis(4'-hydroxyphenyl)-1-cyclohexanol, having three hydroxyl functionalities that can form O-H...O hydrogen-bonded helices. The topology of this network structure finds a parallel in three-connected coordination ... |
11893184 | Self-assembly of molecular prisms via an organometallic "clip". | [reaction: see text] Under the appropriate conditions, the combination of two tritopic pyridyl ligands with three metal-containing molecular "clips" spontaneously generates supramolecular coordination cages with trigonal prismatic frameworks. |
11893176 | Protons as the triggers to regulate hydrogen-bonding receptors. | [reaction: see text] The protonation of alkylamines in two novel receptors results in intramolecular host-guest associations between the resulting ammonium ions and crown ether macrocycles. These interactions result in conformational changes of the receptors and prevent them from acting as hydrogen bond complements for... |
11893341 | Structure of dengue virus: implications for flavivirus organization, maturation, and fusion. | The first structure of a flavivirus has been determined by using a combination of cryoelectron microscopy and fitting of the known structure of glycoprotein E into the electron density map. The virus core, within a lipid bilayer, has a less-ordered structure than the external, icosahedral scaffold of 90 glycoprotein E ... |
11891663 | Chronic alterations in serotonin function: dynamic neurochemical properties in agonistic behavior of the crayfish, Orconectes rusticus. | The biogenic amine serotonin [5-hydroxytryptamine (5-HT)] has received considerable attention for its role in behavioral phenomena throughout a broad range of invertebrate and vertebrate taxa. Acute 5-HT infusion decreases the likelihood of crayfish to retreat from dominant opponents. The present study reports the bioc... |
11890829 | Adsorption geometry of 4-picoline chemisorbed on the Cu(110) surface: a study of forces controlling molecular self-assembly. | The adsorption of 4-picoline (4-methylpyridine) on the Cu(110) surface has been studied with time-of-flight electron stimulated desorption ion angular distribution (TOF-ESDIAD) and other methods. Using deuterium labeling in the methyl group and hydrogen labeling on the aromatic ring, it has been possible to separately ... |
11890788 | Quantum dot on a rope. | The conjugation of nanoparticles (NPs) typically yields supramolecular materials which are fairly rigid, and the electronic coupling between the NP and other structural units of these compounds is fixed by covalent bonds. Here, we report on a novel bichromophor system constructed from a quantum dot tethered to a semico... |
11890773 | Intramolecular Förster energy transfer in a dendritic system at the single molecule level. | The photophysics of a dendrimer containing four donor chromophores and one acceptor chromophore are studied at the single-molecule level. Upon excitation of the donors exclusive acceptor emission is observed due to efficient Förster energy transfer. For 70% of the molecules donor emission is observed after bleaching of... |
11891911 | Supramolecular polymers generated from heterocomplementary monomers linked through multiple hydrogen-bonding arrays--formation, characterization, and properties. | Supramolecular polymers are described that are derived from the association of two homoditopic heterocomplementary monomers through sextuple hydrogen-bonding arrays. They form fibers and a variety of different materials depending on the conditions. The strong affinity of the DAD-DAD (D=donor, A=acceptor) hydrogen-bondi... |
11891906 | Porphyrin-based peptide receptors: syntheses and NMR analysis. | The synthesis and purification of a water-soluble host compound that contains three pyridinium units and one spacer-connected benzocrown ether unit in the meso-positions of porphyrin and of its Zn(II) or Cu(II) complexes is described. Metalation leads to small (compared to the apo-derivative) changes of selectivities w... |
11891901 | Missing-link macrocycles: hybrid heterocalixarene analogues formed from several different building blocks. | The synthesis and structural characterization of hybrid heterocalix[4]arene analogues containing pyrrole, benzene, methoxy-substituted benzene, and pyridine subunits is described. Macrocycles 1 and 2, examples of calix[2]benzene[2]pyrrole and calix[1]benzene[3]pyrrole systems, respectively, are synthesized by the conde... |
11891898 | Exploring and expanding the three-dimensional structural diversity of supramolecular dendrimers with the aid of libraries of alkali metals of their AB(3) minidendritic carboxylates. | The synthesis of the alkali metal salts of 3,4,5-tris(n-alkan-1-yloxy)benzoic acid [(3,4,5)nG1-CO(2)M, where n is the number of methylenic units in the alkane group for n=12, 14, 16, 18 and M=Li, Na, K, Rb, Cs] is described. The structural analysis of these AB(3) molecules by a combination of methods which includes X-r... |
11891890 | The impact of rigidity and water exchange on the relaxivity of a dendritic MRI contrast agent. | Variable-temperature, multiple magnetic field (17)O NMR, EPR and variable-temperature (1)H nuclear magnetic relaxation dispersion (NMRD) measurement techniques have been applied to Gadomer 17, a new dendritic contrast agent for magnetic resonance imaging. The macromolecule bears 24 Gd(dota)-monoamide chelates (dota=N,N... |
11890892 | Monte Carlo docking simulations of cyclomaltoheptaose and dimethyl cyclomaltoheptaose with paclitaxel. | The molecular basis for the remarkable enhancement of the solubility of paclitaxel by O-dimethylcyclomaltoheptaose (DM-beta-CD) over cyclomaltoheptaose (beta-cyclodextrin, beta-CD) was investigated with Monte Carlo docking-minimization simulation. As possible guests of inclusion complexation for the host cyclic oligosa... |
11890891 | Crystal structure of the cyclomaltohexaose (alpha-cyclodextrin) complex with isosorbide dinitrate. Guest-modulated channel-type structure. | The crystal structure of the 2:1 complex of cyclomaltohexaose (alpha-cyclodextrin, alpha-CD) with isosorbide dinitrate was determined by single-crystal X-ray analysis. In the crystal with the space group C2, two cyclomaltohexaose molecules form a head-to-head dimer with the secondary hydroxy-group sides facing each oth... |
11890888 | Addition of maltodextrins to the nonreducing-end of acarbose by reaction of acarbose with cyclomaltohexaose and cyclomaltodextrin glucanyltransferase. | New kinds of acarbose analogues were synthesized by the reaction of acarbose with cyclomaltohexaose and cyclomaltodextrin glucanyltransferase (CGTase). Three major CGTase coupling products were separated and purified by Bio-Gel P2 gel-permeation chromatography. Digestion of the three products by beta-amylase and glucoa... |
11890887 | Synthesis and characterization of water-soluble hydroxybutenyl cyclomaltooligosaccharides (cyclodextrins). | We have examined the synthesis of hydroxybutenyl cyclomaltooligosaccharides (cyclodextrins) and the ability of these cyclodextrin ethers to form guest-host complexes with guest molecules. The hydroxybutenyl cyclodextrin ethers were prepared by a base-catalyzed reaction of 3,4-epoxy-1-butene with the parent cyclodextrin... |
11890667 | Molecular aptamer beacons for real-time protein recognition. | One of the most pressing problems facing those attempting to understand the regulation of gene expression and translation is the necessity to monitor protein production in a variety of metabolic states. Thus far, there is no easy solution that will either identify or quantitate proteins in real time. Here we introduce ... |
11889051 | Modification of the human thymine-DNA glycosylase by ubiquitin-like proteins facilitates enzymatic turnover. | DNA glycosylases initiate base excision repair (BER) through the generation of potentially harmful abasic sites (AP sites) in DNA. Human thymine-DNA glycosylase (TDG) is a mismatch-specific uracil/thymine-DNA glycosylase with an implicated function in the restoration of G*C base pairs at sites of cytosine or 5-methylcy... |
11889035 | Late endosome motility depends on lipids via the small GTPase Rab7. | We report that lipids contribute to regulate the bidirectional motility of late endocytic compartments. Late endocytic vesicles loaded with cholesterol lose their dynamic properties, and become essentially immobile, including in cells from Niemann-Pick C patients. These vesicles then retain cytoplasmic dynein activity,... |
11889032 | Conserved segments 1A and 2B of the intermediate filament dimer: their atomic structures and role in filament assembly. | Intermediate filaments (IFs) are key components of the cytoskeleton in higher eukaryotic cells. The elementary IF 'building block' is an elongated coiled-coil dimer consisting of four consecutive alpha-helical segments. The segments 1A and 2B include highly conserved sequences and are critically involved in IF assembly... |
11888315 | Elastin-based biopolymers: chemical synthesis and structural characterization of linear and cross-linked poly(OrnGlyGlyOrnGly). | Poly(OrnGlyGlyOrnGly) was synthesized by classical procedures in solution. The monomeric sequence -OrnGlyGlyOrnGly- was chosen as a modification of -ValGlyGlyValGly-, typical of elastin, to impart primary amine functionality, susceptible to cross-linking with appropriate bifunctional reagents. Herein we focus on the cr... |
11888312 | Amphiphilic block copolymer with a molecular recognition site: induction of a novel binding characteristic of amylose by self-assembly of poly(ethylene oxide)-block-amylose in chloroform. | Solution properties of amphiphilic methoxy poly(ethylene oxide)-block-amyloses (MPEO-amyloses) in chloroform were investigated by SLS and DLS. The results indicated that MPEO-amyloses dissolved in chloroform containing 2 wt % DMSO by their self-associations. The complexation of MPEO-amylose with methyl orange (MO) was ... |
11888311 | A new strategy for the preparation of supramolecular neutral hydrogels. | This paper demonstrates that miscible blends from water-insoluble polymers, such as poly(2,4,4-trimethylhexamethylene terephthalamide) (1), methylamine imidized poly(methyl methacrylate) (2), and aromatic poly(ether sulfone) (3) and water-soluble polymers, such as poly(2-ethyl-2-oxazoline) (4) and poly(N-vinyl pyrrolid... |
11888304 | Lipase-catalyzed synthesis of a pure macrocyclic polyester from dimethyl terephthalate and diethylene glycol. | The polymerization of dimethyl terephthalate and diethylene glycol by enzymic catalysis in toluene is described. The potential pi-pi interactions of the aromatic rings together with the relative flexibility of the diol segment have been regarded as synergy factors responsible for the formation of a pure cyclic compound... |
11888201 | Mapping of the chick heme oxygenase-1 proximal promoter for responsiveness to metalloporphyrins. | Heme oxygenase (HO) catalyzes the rate-controlling step of physiologic heme catabolism, namely, the oxidation of the alpha-methene bridge of the macrocycle with formation of CO, Fe, and biliverdin. HO-1, the first isoform of HO to be identified, is highly inducible by a large number of physical and chemical factors. Ma... |
11888060 | Quantification of terbutaline in urine by enzyme-linked immunosorbent assay and capillary electrophoresis after oral and inhaled administrations. | The International Olympic Committee and World AntiDoping Agency restricts the use of beta2-agonists and only the inhaled administration of terbutaline, salbutamol, formoterol and salmeterol is permitted for therapeutic reasons. The aim of this study was to develop a test for the quantitation of terbutaline in urine and... |
11884217 | A novel evaluation of subcutaneous formulations by in vivo magnetic resonance imaging (MRI). | The applicability of magnetic resonance imaging (MRI) for non-invasive in vitro studies of parenteral vehicles without use of marker substances was investigated. A wide range of extended release (ER) formulations such as oils, a lipid emulsion, and water solutions of a cyclodextrin and block co-polymers were visualized... |
11884643 | Construction and electrophoretic migration of single-stranded DNA knots and catenanes. | In recent years there has been growing interest in the question of how the particular topology of polymeric chains affects their overall dimensions and physical behavior. The majority of relevant studies are based on numerical simulation methods or analytical treatment; however, both these approaches depend on various ... |
11884453 | Two new isotype-specific switching activities detected for Ig class switching. | Ig class switch recombination (CSR) occurs by an intrachromosomal deletional process between switch (S) regions in B cells. To facilitate the study of CSR, we derived a new B cell line, 1.B4.B6, which is uniquely capable of mu --> gamma3, mu --> epsilon, and mu --> alpha, but not mu --> gamma1 CSR at its endogenous loc... |
11884371 | Lovastatin enhances ecto-5'-nucleotidase activity and cell surface expression in endothelial cells: implication of rho-family GTPases. | Extracellular adenosine production by the GPI-anchored Ecto-5'-Nucleotidase (Ecto-5'-Nu) plays an important role in the cardiovascular system, notably in defense against hypoxia. It has been previously suggested that HMG-CoA reductase inhibitors (HRIs) could potentiate the hypoxic stimulation of Ecto-5'Nu in myocardial... |
11882701 | Influence of activated charcoal, porcine gastric mucin and beta-cyclodextrin on the morphology and growth of intestinal and gastric Helicobacter spp. | Bile-tolerant Helicobacter spp. are emerging human and animal pathogens. However, due to their fastidious nature, which requires nutrient-rich complex media to grow, infection with these bacteria may be underestimated. The accumulation of toxic metabolites in cultures may be one of the main obstacles for successful cul... |
11882543 | Modulation of ISWI function by site-specific histone acetylation. | Mutations in Drosophila ISWI, a member of the SWI2/SNF2 family of chromatin remodeling ATPases, alter the global architecture of the male X chromosome. The transcription of genes on this chromosome is increased 2-fold relative to females due to dosage compensation, a process involving the acetylation of histone H4 at l... |
11882541 | Histone acetylation: a switch between repressive and permissive chromatin. Second in review series on chromatin dynamics. | The organization of eukaryotic chromatin has a major impact on all nuclear processes involving DNA substrates. Gene expression is affected by the positioning of individual nucleosomes relative to regulatory sequence elements, by the folding of the nucleosomal fiber into higher-order structures and by the compartmentali... |
11880628 | Rationally designed mutations convert de novo amyloid-like fibrils into monomeric beta-sheet proteins. | Amyloid fibrils are associated with a variety of neurodegenerative maladies including Alzheimer's disease and the prion diseases. The structures of amyloid fibrils are composed of beta-strands oriented orthogonal to the fibril axis ("cross beta" structure). We previously reported the design and characterization of a co... |
11880619 | A cofactor approach to copper-dependent catalytic antibodies. | A strategy for the preparation of semisynthetic copper(II)-based catalytic metalloproteins is described in which a metal-binding bis-imidazole cofactor is incorporated into the combining site of the aldolase antibody 38C2. Antibody 38C2 features a large hydrophobic-combining site pocket with a highly nucleophilic lysin... |
11880614 | Chemical amplification with encapsulated reagents. | Autocatalysis and chemical amplification are characteristic properties of living systems, and they give rise to behaviors such as increased sensitivity, responsiveness, and self-replication. Here we report a synthetic system in which a unique form of compartmentalization leads to nonlinear, autocatalytic behavior. The ... |
11880397 | Streptococcus sinensis sp. nov., a novel species isolated from a patient with infective endocarditis. | A bacterium was isolated from the blood culture of a patient with infective endocarditis. The cells were facultative anaerobic, nonsporulating, gram-positive cocci arranged in chains. The bacterium grows on sheep blood agar as alpha-hemolytic, gray colonies of 0.5 to 1 mm in diameter after 24 h of incubation at 37 degr... |
11879917 | NMR study of cyclic peptides with renin inhibitor activity. | Several cyclic analogues of renin inhibitors, based on Glu-D-Phe-Lys motif have been investigated by NMR spectroscopy and molecular dynamics calculations (MD). The 15 membered macrocycle, resulting from Glu and Lys side-chain cyclization, exhibits conformational preference. The structural evidence from NMR shows the pr... |
11878981 | Ion channel formation from a calix[4]arene amide that binds HCl. | The ion transport activity of calix[4]arene tetrabutylamide 1,3-alt 2 was studied in liposomes, planar lipid bilayers, and HEK-293 cells. These experiments, when considered together with (1)H NMR and X-ray crystallography data, indicate that calix[4]arene tetrabutylamide 2 (1) forms ion channels in bilayer membranes, (... |
11878967 | Designed self-assembly of molecular necklaces. | This paper reports an efficient strategy to synthesize molecular necklaces, in which a number of small rings are threaded onto a large ring, utilizing the principles of self-assembly and coordination chemistry. Our strategy involves (1) threading a molecular "bead" with a short "string" to make a pseudorotaxane and the... |
11878961 | A self-organized 2-dimensional bifunctional structure formed by supramolecular design. | The production of a novel two-dimensional bimolecular surface structure using weak noncovalent interactions is demonstrated and observed by scanning tunneling microscopy. This work follows the three-dimensional (3D) ideas of crystal engineering and applies the concepts of supramolecular synthons to molecular systems co... |
11878959 | Supramolecular stabilization of N(2)H(7)(+). | The cation N(2)H(7)(+) has been stabilized in a largely hydrophobic supramolecular environment and characterized in the solid state. The cation is situated in the bowl-shaped cavity of calix[4]arene. All of the hydrogen atoms are clearly discernible owing to high-quality X-ray data as well as lack of disorder and symme... |
11878945 | Unanticipated guest motion during a phase transition in a ferroelastic inclusion compound. | Urea inclusion compounds (UICs) have been used as tools to understand ferroelastic domain switching and molecular recognition during crystal growth. Although the vast majority of UICs contain helical arrangements of host H-bonds, those containing guests with the formula X(CH(2))(6)Y (X, Y = Br, Cl, CN, NC) adopt an alt... |
11879012 | Modulation of cyclizing activity and thermostability of cyclodextrin glucanotransferase and its application as an antistaling enzyme. | Cyclodextrin glucanotransferase from Bacillus stearothermophilus ET1 (CGTase ET1) is a potential antistaling enzyme with cyclodextrin (CD)-forming activity. To reduce cyclization activity of CGTase ET1, phenylalanine residues at 191 and 255 were replaced with a glycine (F191G-CGTase ET1) and an isoleucine (F255I-CGTase... |
11879002 | Study on the supramolecular interaction of curcumin and beta-cyclodextrin by spectrophotometry and its analytical application. | The supramolecular interaction of curcumin and beta-cyclodextrin (beta-CD) has been studied by spectrophotometry. The mechanism of the inclusion was studied and discussed based on the variations of pK(a), absorption intensity, and infrared spectrograms. The results show that beta-CD reacts with curcumin to form a 2:1 h... |
11879753 | Paclitaxel and its formulations. | Paclitaxel (Taxol) is a promising anti-tumor agent with poor water solubility. It is effective for various cancers especially ovarian and breast cancer. Intravenous administration of a current formulation in a non-aqueous vehicle containing Cremophor EL may cause allergic reactions and precipitation on aqueous dilution... |
11879203 | Comparison between Ca2+-induced scrambling of various fluorescently labelled lipid analogues in red blood cells. | Treatment of red blood cells with calcium and ionomycin causes activation of the lipid scramblase, a putative membrane protein catalysing flip-flop of (phospho)lipids. Various fluorescent 1-oleoyl-2-[6(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino] caproyl (C(6)-NBD) analogues were tested for transbilayer movement across the... |
11877482 | Lipid raft microdomains: a gateway for compartmentalized trafficking of Ebola and Marburg viruses. | Spatiotemporal aspects of filovirus entry and release are poorly understood. Lipid rafts act as functional platforms for multiple cellular signaling and trafficking processes. Here, we report the compartmentalization of Ebola and Marburg viral proteins within lipid rafts during viral assembly and budding. Filoviruses r... |
11877382 | Distinct requirements for TrkB and TrkC signaling in target innervation by sensory neurons. | Signaling by brain-derived neurotrophic factor (BDNF) via the TrkB receptor, or by neurotrophin-3 (NT3) through the TrkC receptor support distinct populations of sensory neurons. The intracellular signaling pathways activated by Trk (tyrosine kinase) receptors, which in vivo promote neuronal survival and target innerva... |
11877344 | Algogen-specific pain processing in mouse spinal cord: differential involvement of voltage-dependent Ca(2+) channels in synaptic transmission. | 1. The effects of intrathecal (i.t.) administration of N-, P/Q- or L-type voltage-dependent Ca(2+)-channel blockers were tested in two pain models involving bradykinin (BK)- and alpha,beta-methylene ATP (alpha,beta meATP)-induced activation of primary afferent neurons in mice. 2. The nociceptive response (amount of tim... |
11877323 | Extracellular signal-regulated kinase plays an essential role in endothelin-1-induced homotypic adhesion of human neutrophil granulocytes. | 1. Endothelin-1 (ET-1) stimulates integrin-dependent adhesion of neutrophil granulocytes to endothelial cells, one of the early key events in acute inflammation. However, the signalling pathway(s) of ET-1-stimulated neutrophil adhesive responses has not been elucidated. Previous studies indicated that extracellular sig... |
11876635 | Role of electrostatics in the interaction between cytochrome f and plastocyanin of the cyanobacterium Phormidium laminosum. | The role of charged residues on the surface of plastocyanin from the cyanobacterium Phormidium laminosum in the reaction with soluble cytochrome f in vitro was studied using site-directed mutagenesis. The charge on each of five residues on the eastern face of plastocyanin was neutralized and/or inverted, and the effect... |
11875429 | Carbohydrate microarrays for the recognition of cross-reactive molecular markers of microbes and host cells. | We describe here the development of a carbohydrate-based microarray to extend the scope of biomedical research on carbohydrate-mediated molecular recognition and anti-infection responses. We have demonstrated that microbial polysaccharides can be immobilized on a surface-modified glass slide without chemical conjugatio... |
11874343 | Metal ion-dependent molecular inclusion chemistry: inclusion of aromatic anions by coordinated 1,4,7,10-tetrakis((S)-2-hydroxy-3-phenoxypropyl)-1,4,7,10-tetraazacyclododecane. | The ability of the pendant donor macrocyclic ligand 1,4,7,10-tetrakis((S)-2-hydroxy-3-phenoxypropyl)-1,4,7,10-tetraaza- cyclododecane((S)-thphpc12) (or [Cd((S)-thphpc12)](2+)) to act as a metal ion-dependent receptor for aromatic anions has been investigated in solution and in the solid state. [Cd((S)-thphpc12)](2+) ad... |
11874338 | Synthesis, structure, and photophysical studies of luminescent two- and three-dimensional gold-thallium supramolecular arrays. | The reactions of tetrahydrofuran solutions of NBu(4)[AuR(2)] (R = C(6)F(5), C(6)Cl(5)) with TlPF(6) and 4,4'-bipyridine lead to the synthesis of the luminescent materials [Tl(bipy)](2)[Au(C(6)F(5))(2)](2) 1 and [Tl(bipy)][Tl(bipy)(0.5)(thf)][Au(C(6)Cl(5))(2)](2) 2 in high yield. The structures of these complexes, as an... |
11874332 | New rigid angular dicarboxylic acid for the construction of nanoscopic supramolecules: from a molecular rectangle to a 1-D coordination polymer. | A new rigid angular bridging ligand, 7-oxa-dibenzofluorene-3,11-dicarboxylic acid (H(2)L), was synthesized by cyanation of known rac-6,6'-dibromo-1,1'-bi-2-naphthol followed by ring closure and hydrolysis with concentrated sulfuric acid and used for the self-assembly of nanoscopic molecular rectangle [Cu(4)(L)(4)(Py)(8... |
11874469 | Functional studies of the Synechocystis phycobilisomes organization by high performance liquid chromatography on line with a mass spectrometer. | This study was designed to yield data on the supramolecular organization of the phycobilisome apparatus from Synechocystis, and the possible effects of environmental stress on this arrangement. Phycobilisomes were dissociated in a low ionic strength solution and a quantitative estimation of the protein components prese... |
11874464 | Functional epitope of common gamma chain for interleukin-4 binding. | Interleukin 4 (IL-4) can act on target cells through an IL-4 receptor complex consisting of the IL-4 receptor alpha chain and the common gamma chain (gamma(c)). An IL-4 epitope for gamma(c) binding has previously been identified. In this study, the gamma(c) residues involved in IL-4 binding were defined by alanine-scan... |
11874392 | Levormeloxifene: safety, pharmacodynamics and pharmacokinetics in healthy postmenopausal women following single and multiple doses of a new selective oestrogen receptor modulator. | <h4>Aims</h4>The safety, pharmacodynamics and pharmacokinetics of levormeloxifene, a selective oestrogen receptor modulator (SERM), were investigated in postmenopausal women following single doses and multiple dosing once daily up to 56 days.<h4>Methods</h4>The two randomized, double-blind, placebo controlled studies o... |
11871897 | Synthesis and NMR studies of (13)C-labeled vitamin D metabolites. | Isotope-labeled drug molecules may be useful for probing by NMR spectroscopy the conformation of ligand associated with biological hosts such as membranes and proteins. Triple-labeled [7,9,19-(13)C(3)]-vitamin D(3) (56), its 25-hydroxylated and 1 alpha,25-dihydroxylated metabolites (58 and 68, respectively), and other ... |
11871870 | Templated conversion of a crown ether-containing macrobicycle into [2]rotaxanes. | A crown ether-containing macrobicycle was used as the wheel component in a templated synthesis of a [2]rotaxane with an acetal-containing axle. The molecular structures of the macrobicycle and the [2]rotaxane were characterized by NMR spectroscopy and X-ray crystallography. The chloride-binding ability of the macrobicy... |
11872719 | An extracellular matrix-associated zinc metalloprotease is required for dilauroyl phosphatidylethanolamine chemotactic excitation in Myxococcus xanthus. | An extracellular matrix connects bacteria that live in organized assemblages called biofilms. While the role of the matrix in the regulation of cell behavior has not been extensively examined in bacteria, we suggest that, like mammalian cells, the matrix facilitates cell-cell interactions involved with regulation of co... |
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