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14528004 | Biomolecular hydration: from water dynamics to hydrodynamics. | Thermally driven rotational and translational diffusion of proteins and other biomolecules is governed by frictional coupling to their solvent environment. Prediction of this coupling from biomolecular structures is a longstanding biophysical problem, which cannot be solved without knowledge of water dynamics in an int... |
14528000 | Functional map and domain structure of MET, the product of the c-met protooncogene and receptor for hepatocyte growth factor/scatter factor. | Little is known about the large ectodomain of MET, the product of the c-met protooncogene and receptor for hepatocyte growth factor/scatter factor (HGF/SF). Here, we establish by deletion mutagenesis that the HGF/SF and heparin-binding sites of MET are contained within a large N-terminal domain spanning the alpha-chain... |
14579432 | Binding affinities of host-guest, protein-ligand, and protein-transition-state complexes. | The affinities of hosts-ranging from small synthetic cavitands to large proteins-for organic molecules are well documented. The average association constants for the binding of organic molecules by cyclodextrins, synthetic hosts, and albumins in water, as well as of catalytic antibodies or enzymes for substrates are 10... |
14579431 | Electrochemical and photochemical control of host-guest complexation at surfaces. | The application of electrochemistry or photochemistry to modulate supramolecular interactions between host-guest systems in solution is a burgeoning field. In particular, the speed and reversibility associated with electrochemically or photochemically actuated supramolecular interactions has allowed the creation and mo... |
14726636 | Targeted molecular imaging. | Molecular imaging aims to visualize the cellular and molecular processes occurring in living tissues, and for the imaging of specific molecules in vivo, the development of reporter probes and dedicated imaging equipment is most important. Reporter genes can be used to monitor the delivery and magnitude of therapeutic g... |
14710806 | Integrated hydrogenated amorphous Si photodiode detector for microfluidic bioanalytical devices. | Hydrogenated amorphous silicon (a-Si:H) PIN photodiodes have been developed and characterized as fluorescence detectors for microfluidic analysis devices. A discrete a-Si:H photodiode is first fabricated on a glass substrate and used to detect fluorescent dye standards using conventional confocal microscopy. In this fo... |
14522816 | Sphingomyelinase activates GLUT4 translocation via a cholesterol-dependent mechanism. | A basis for the insulin mimetic effect of sphingomyelinase on glucose transporter isoform GLUT4 translocation remains unclear. Because sphingomyelin serves as a major determinant of plasma membrane cholesterol and a relationship between plasma membrane cholesterol and GLUT4 levels has recently become apparent, we asses... |
14685044 | [Development of nasal dosage form of oxatomide for rhinitis]. | The possibility of oxatomide as the nasal dosage drug for the therapy of nasal allergy was studied. Oxatomide was well absorbed from the nasal cavity, indicating a high permeability to nasal epithelial layer after nasal administration. Acidic pH condition further enhanced the permeation of oxatomide across Caco-2 monol... |
14669990 | Molecular recognition between Azotobacter vinelandii rhodanese and a sulfur acceptor protein. | The occurrence of rhodanese-like proteins in the major evolutionary phyla, together with the observed abundance of these proteins also within the same genome, suggests that their function cannot be limited to cyanide scavenging. The aim of the present study was to investigate whether Azotobacter vinelandii RhdA, an enz... |
14649214 | Delivery of testosterone replacement therapy. | Optimal testosterone replacement therapy remains a considerable challenge for the estimated five out of 1000 men in the general community with androgen deficiency. Oral delivery is not possible due to rapid first pass metabolism and short half-life. Testosterone derivatives have been developed to enhance intrinsic andr... |
14639748 | Luminescent lanthanide chelate contrast agents and detection of lesions in the hamster oral cancer model. | Lanthanide chelates are a somewhat unique class of molecules that have proven to be useful in the biomedical field due to their extremely large Stokes' shift and long fluorescent lifetimes. The ability of these molecules to produce fluorescence in the low- or zero-back-ground regime makes this class of molecules excell... |
14637021 | Conformation and self-assembly of a nystatin nitrobenzoxadiazole derivative in lipid membranes. | Nystatin is a polyene (tetraene) macrolide antibiotic presenting antifungal activity that acts at the cellular membrane level. In the present study, we report the interaction of this antibiotic labelled at its amine group with 7-nitrobenz-2-oxa-1,3-diazole (NBD-Nys) with sterol-free and ergosterol- and cholesterol-cont... |
14637014 | Lipid rafts in epithelial brush borders: atypical membrane microdomains with specialized functions. | Epithelial cells that fulfil high-throughput digestive/absorptive functions, such as small intestinal enterocytes and kidney proximal tubule cells, are endowed with a dense apical brush border. It has long been recognized that the microvillar surface of the brush border is organized in cholesterol/sphingolipid-enriched... |
14624689 | Following severe injury, hypocholesterolemia improves with convalescence but persists with organ failure or onset of infection. | <h4>Introduction</h4>Our primary objective was to determine the impact of traumatic injury, onset of infection, organ/metabolic dysfunction, and mortality on serum cholesterol.<h4>Methods</h4>During 676 surgical intensive care unit (SICU) days, 28 ventilated trauma patients underwent daily measurement of white blood ce... |
14618259 | Yeast as a sensor of factors affecting the accuracy of protein synthesis. | The cell monitors and maintains the fidelity of translation during the three stages of protein synthesis: initiation, elongation and termination. Errors can arise by multiple mechanisms, such as altered start site selection, reading frame shifts, misincorporation or nonsense codon suppression. All of these events produ... |
14618258 | Bacterial oligopeptide-binding proteins. | This review focuses on bacterial oligopeptide-binding proteins, which form part of the oligopeptide transport system belonging to the ATP-binding cassette family of transporters. Depending on the bacterial species, these binding proteins (OppA) capture peptides ranging in size from 2 to 18 amino acids from the environm... |
14618253 | The odd couple: signal transduction and endocytosis. | Cell surface receptors are used to transmit extracellular information. The activation of cell surface receptors initiates signal transduction and receptor endocytosis. Signal transduction and the endosomal transport of activated receptors require precise regulation. New concepts for the integration of endocytosis and s... |
14620518 | Enhancement of solubility and bioavailability of beta-lapachone using cyclodextrin inclusion complexes. | <h4>Purpose</h4>To explore the use of cyclodextrins (CD) to form inclusion complexes with beta-lapachone (beta-lap) to overcome solubility and bioavailability problems previously noted with this drug.<h4>Methods</h4>Inclusion complexes between beta-lap and four cyclodextrins (alpha-, beta-, gamma-, and HPbeta-CD) in aq... |
14620506 | Pulmonary absorption of insulin mediated by tetradecyl-beta-maltoside and dimethyl-beta-cyclodextrin. | <h4>Purpose</h4>To determine if tetradecyl-beta-maltoside (TDM) and dimethyl-beta-cyclodextrin (DMbetaCD) enhance pulmonary absorption of insulin and to investigate if they do so by a reversible action on respiratory epithelium.<h4>Methods</h4>Insulin formulated with saline, TDM, or DMbetaCD was administered intratrach... |
14620505 | Engineering of dendrimer surfaces to enhance transepithelial transport and reduce cytotoxicity. | <h4>Purpose</h4>To evaluate the cytotoxicity, permeation, and transport mechanisms of PAMAM dendrimers and surface-modified cationic PAMAM dendrimers using monolayers of the human colon adenocarcinoma cell line, Caco-2.<h4>Methods</h4>Cytotoxicity was determined using the MTT assay. The effect of dendrimers on monolaye... |
14612133 | Probing conformational changes in neurotransmitter transporters: a structural context. | The Na+/Cl-dependent neurotransmitter transporters, a family of proteins responsible for the reuptake of neurotransmitters and other small molecules from the synaptic cleft, have been the focus of intensive research in recent years. The biogenic amine transporters, a subset of this larger family, are especially intrigu... |
14609284 | Controlled release of nifedipine from mucoadhesive tablets of its inclusion complexes with beta-cyclodextrin. | Mucoadhesive tablets formulated with nifedipine (N) alone and its inclusion complexes with beta-cyclodextrin (betaCD) and the mucoadhesive polymers sodium carboxy methylcellulose and carbopol were investigated with a view to the design of oral controlled release tablets of nifedipine. As nifedipine is practically insol... |
14607974 | Assembly of mammalian septins. | Septins are a conserved family of polymerizing guanine nucleotide binding proteins associated with diverse processes in dividing and non-dividing cells. In humans, 12 septin genes generate dozens of polypeptides, many of which comprise heterooligomeric complexes. Native and recombinant mammalian septin complexes are pu... |
14606755 | Novel laser-induced luminescence resulting from benzophenone/O-propylated p-tert-butylcalix[4]arene complexes. A diffuse reflectance study. | Laser-induced room temperature luminescence of air-equilibrated benzophenone/O-propylated p-tert-butylcalix[4]arene solid powdered samples revealed the existence of a novel emission, in contrast with benzophenone/p-tert-butylcalix[4]arene complexes, where only benzophenone emits. This novel emission was identified as p... |
14606667 | Inclusion complexation of artemisinin with alpha-, beta-, and gamma-cyclodextrins. | The present study was conducted to investigate the inclusion complexation of artemisinin (ART) with natural cyclodextrins (CyD), namely alpha-, beta-, and gamma-CyDs with the aim of improving its solubility and dissolution rate. Complex formation in aqueous solution and solid state was studied by solubility analysis, d... |
14601836 | Use of mobile phase 18-crown-6 to improve peak resolution between mono- and divalent metal and amine cations in ion chromatography. | It is difficult to quantify NH4+ by ion chromatography in the presence of high concentrations of Na+ due to peak overlap. The Dionex IonPac CS15 column, which contains phosphonate, carboxylate, and 18-crown-6 functional groups, was originally developed to overcome this problem. We have found that the addition of 18-cro... |
14599476 | In vitro toxicity testing of supramolecular sensitizers for photodynamic therapy. | We report the phototoxicity of meso-tetrakis(4-sulphonatophenyl)porphine (TPPS4) and zinc metallocomplex (ZnTPPS4) sensitizers in the presence or absence of 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CD) on G361human melanoma cells. Morphological changes in cell cultures have been evaluated using inversion fluorescent ... |
14599006 | Nucleation-elongation: a mechanism for cooperative supramolecular polymerization. | The kinetic and thermodynamic characteristics of polymerizations following a cooperative, nucleation-elongation mechanism are discussed in comparison to those of non-cooperative, isodesmic polymerizations. Nucleation-elongation polymerization is a relatively unexplored avenue of synthetic polymer chemistry and offers s... |
14596007 | Nanoscopic structure of a metallo-supramolecular polyelectrolyte--amphiphile complex, elucidated by X-ray scattering and molecular modeling. | A combination of molecular modeling and X-ray scattering was used to elucidate the structure of the metallosupramolecular polyelectrolyte--amphiphile complex (PAC) self-assembled from FeII, 1,4-bis(2,2':6,'2"-terpyridin-4'-yl)benzene, and dihexadecyl phosphate (DHP). An approximate structure of the semi-ordered materia... |
14596418 | Crystal structure of 6-oxa-3,9-dithiabicyclo[9.2.2]pentadeca-1(15),11,13-triene. | The structure of an S2O mixed-donor macrocycle incorporating para-substituted xylyl subunit was characterized by a single crystal X-ray analysis. The crystal structure shows an exo-dentate orientation of sulfur and oxygen donor atoms due to the fully stretched aliphatic ring conformation. Thus all of torsional angles b... |
14594293 | Synthesis and inclusion properties of a novel macrocyclic hexaketone monohydrate with a hemiacetal structure. | A macrocyclic hexaketone monohydrate was synthesized by the oxidation of either tribenzohexadehydro[12]annulene or tribenzotetradehydro[12]annulene-1,2-dione with ruthenium catalysts; the hexaketone monohydrate incorporates small molecules with a hydroxy, carbonyl or ether group in the crystalline lattice to form inclu... |
14594261 | Synthetic multifunctional pores: lessons from rigid-rod beta-barrels. | In this account, studies on synthetic multifunctional pores formed by rigid-rod beta-barrels are summarized comprehensively. The first section outlines the evolution of synthetic multifunctional pores from the introduction of rigid-rod molecules in bioorganic chemistry and the discovery of synthetic beta-barrels in com... |
14587755 | Macrocyclic diiminodipyrromethane complexes: structural analogues of Pac-Man porphyrins. | The complexation of palladium(II) by a unique family of [2+2] diiminodipyrromethane macrocycles yields compounds that adopt structures reminiscent of Pac-Man porphyrins. |
14587738 | Bidentate ligands formed by self-assembly. | A novel supramolecular strategy to prepare bidentate ligands via the assembly of functionalised monomeric ligands on a dimeric zinc(II) porphyrin template is presented; the assembled bidentate ligands show chelating behaviour and their rhodium complexes display enhanced selectivity in the hydroformylation compared to t... |
14587715 | Fluorescent supramolecular liquid crystalline polymers from nucleobase-terminated monomers. | While thymine or N6-(4-methoxybenzoyl)adenine terminated bis(4-alkoxy)-substituted bis(phenylethynyl)benzene monomers show no liquid crystalline behaviour by themselves, mixing the complementary nucleobase monomers together results in the formation of thermotropic liquid crystalline phases. |
14587713 | H+, Na+ and K+ modulated lanthanide luminescent switching of Tb(III) based cyclen aromatic diaza-crown ether conjugates in water. | The cyclen based aromatic diaza-15-crown-5 and 18-crown-6 ether conjugates 1Tb-4Tb were designed as luminescent switches for sodium and potassium where the delayed Tb(III) emission, occurring as line-like emission bands between 490-622 nm, was 'switched on' upon recognition of these ions in pH 7.4 buffered water soluti... |
14587712 | The first liquid-crystalline, expanded porphyrins. | Aliphatic derivatives of hydrazinophyrin, a new type of tetrapyrrolic macrocycle prepared by the condensation of 2,5-diformylpyrroles with hydrazine, exhibit liquid crystalline properties as judged from polarising optical microscopy; these hydrazinophyrins appear to be the first mesogens derived from an expanded porphy... |
14587707 | A supramolecular cup-and-ball C60-porphyrin conjugate system. | In addition to the ammonium-crown ether recognition, pi-stacking interactions between the C60 sphere and the porphyrin moiety have been evidenced in a supramolecular complex obtained from a porphyrin-crown ether conjugate and a fullerene derivative bearing an ammonium unit. |
14584810 | Neutral pi-associated porphyrin [2]catenanes. | A series of neutral porphyrin-containing catenanes has been synthesised, consisting of a zinc porphyrin strapped by a polyethylene glycol chain containing four or six ethylenoxy-units and incorporating a central naphthoquinol unit, interlinked with a naphthalene diimide macrocycle. The napthalene diimide precursor unit... |
14584804 | Macrocyclic amines as catalysts of the hydrolysis of the triphosphate bridge of the mRNA 5'-cap structure. | The reactions of a 5'-cap model compound P1-(7-methylguanosine) P3-guanosine 5',5'-triphosphate, m7GpppG, were studied in the presence of three different macrocyclic amines (2-4) under neutral conditions. The only products observed in the absence of the macrocycles resulted from the base-catalysed imidazole ring-openin... |
14584785 | Rigid optically-active D2 and D3 macrocycles. | The synthesis and characterization of novel optically-active macrocycles, obtained by esterification reaction from a binaphthyl-containing diol and phthalic or terephthalic acids, and possessing overall D2 or D3 symmetry, is described. |
14580674 | Sustained expression in mammalian cells with DNA complexed with chitosan nanoparticles. | This work investigates the preparation and in vitro efficiency of chitosan gene transfection systems. Chitosan was used to prepare nanoparticles with a size range of 40-200 nm as determined using photon correlation spectroscopy (PCS) and 40-80 nm as determined using transmission electron microscopy (TEM). The ability o... |
14578049 | Fluorescence evidence for a loose self-assembly of the fusion peptide of influenza virus HA2 in the lipid bilayer. | Steady state fluorescence experiments were performed on a 25-mer synthetic peptide incorporated in the phospholipid vesicle to study the role of oligomerization of the fusion peptide in membrane fusion. It was found from fluorescence resonance energy transfer (FRET) that the extent of lipid mixing and the initial mixin... |
14578047 | Mixed lipid aggregates containing gangliosides impose different 2H-NMR dynamical parameters on water environment depending on their lipid composition. | Water dynamics in samples of ceramide tetrasaccharide (Gg4Cer) vesicles and GM1 ganglioside micelles at 300:1 water/lipid mole ratio were studied by using deuterium nuclear magnetic resonance (2H-NMR). GM1 imposes a different restriction on water dynamics that is insensitive to temperatures either above or below its ph... |
14577586 | Adenosine protects against angiotensin II-induced apoptosis in rat cardiocyte cultures. | Adenosine has been found to be cardioprotective during episodes of cardiac ischemia/reperfusion through activation of the A1 and possibly A1 receptors. Therefore, we have investigated whether activation of these receptors can protect also against apoptotic death induced by angiotensin II (Ang II) in neonatal rat cardio... |
14576428 | Experimental models of primitive cellular compartments: encapsulation, growth, and division. | The clay montmorillonite is known to catalyze the polymerization of RNA from activated ribonucleotides. Here we report that montmorillonite accelerates the spontaneous conversion of fatty acid micelles into vesicles. Clay particles often become encapsulated in these vesicles, thus providing a pathway for the prebiotic ... |
14576838 | Mechanisms of Taxol resistance related to microtubules. | Since its approval by the FDA in 1992 for the treatment of ovarian cancer, the use of Taxol has dramatically increased. Although treatment with Taxol has led to improvement in the duration and quality of life for some cancer patients, the majority eventually develop progressive disease after initially responding to Tax... |
14575508 | Unexpected single-step formation of 1,2-anti-heterodisubstituted calix[4]arenes upon alkylation of a tribenzoyl precursor. | The selective preparation and complete structural characterization of a small series of 1,2-anti-heterodisubstituted calix[4]arenes has been accomplished. These compounds were obtained in two steps from unsubstituted p-tert-butylcalix[4]arene by tribenzoylation and a subsequent one-pot, two-step sequence involving alky... |
14575485 | Synthesis of 6-mono-6-deoxy-beta-cyclodextrins substituted with isomeric aminobenzoic acids. Structural characterization, conformational preferences, and self-inclusion as studied by NMR spectroscopy in aqueous solution and by X-ray crystallography in the solid state. | The synthesis, purification, and characterization of mono-6-modified-beta-cyclodextrins bearing N-attached o-, m-, and p-aminobenzoic acids (2, 3, and 4, respectively) are presented. The structures in aqueous solution were investigated using one- and two-dimensional NMR spectroscopy. Detailed assignment of the spectra ... |
14575457 | Hydroesterification reactions with palladium-complexed PAMAM dendrimers immobilized on silica. | Highly active, recyclable catalytic systems for the hydroesterification reaction of olefins with methanol and carbon monoxide were prepared by complexing various palladium species to generation zero through four PAMAM dendrimers immobilized on silica. The silica-dendrimer-Pd(PPh2)2 complexes were the most facile recycl... |
14575456 | Supramolecular self-assemblies of beta-cyclodextrins with aromatic tethers: factors governing the helical columnar versus linear channel superstructures. | A series of 6-O-(p-substituted phenyl)-modified beta-cyclodextrin derivatives, i.e., 6-O-(4-bromophenyl)-beta-CD (1), 6-O-(4-nitrophenyl)-beta-CD (2), 6-O-(4-formylphenyl)-beta-CD (3), 6-phenylselenyl-6-deoxy-beta-CD (4), and 6-O-(4-hydroxybenzoyl)-beta-CD (5), were synthesized, and their inclusion complexation behavio... |
14575451 | Novel crystal structure, cis-trans isomerization, and host property of meta-substituted macrocyclic azobenzenes with the shortest linkers. | Azobenzenophanes, in which two (2), three (3), and four (4) azobenzene units are connected cyclically by methylene linkers at the meta positions, were synthesized. The effect of ring strain on the structure and the photochemical and the thermal isomerization of azobenzene were investigated. Complex formation with guest... |
14572274 | Facile synthesis of polyamide dendrimers from unprotected AB2 building blocks. | [structure: see text]. A fast, inexpensive, and highly efficient synthesis of aromatic polyamide dendrimers without the need for protection and deprotection steps has been developed. Dendrons and third-generation polyamide dendrimers were easily prepared by a convergent approach involving activation of a focal point wi... |
14572265 | Stereochemical control of skeletal diversity. | [reaction: see text]. Substrates having appendages that pre-encode skeletal information (sigma-elements) can be converted into products having distinct skeletons using a common set of reaction conditions. The sequential use of the Ugi 4CC-IMDA reaction, followed by allylation, hydrolysis, and acylation of a chiral amin... |
14572240 | Inclusion networks of a calix[5]arene-based exoditopic receptor and long-chain alkyldiammonium ions. | [structure: see text]. Tail-to-tail connection of two cone calix[5]arene moieties by a rigid p-xylyl spacer affords the new exoditopic receptor 3 featuring two pi-rich cavities (assembling cores) in a centrosymmetric divergent arrangement, as established by a single-crystal X-ray analysis. 1H NMR complexation studies o... |
14572636 | Protein refolding assisted by self-assembled nanogels as novel artificial molecular chaperone. | Molecular chaperone-like activity for protein refolding was investigated using nanogels of self-assembly of cholesterol-bearing pullulan. Nanogels effectively prevented protein aggregation (i.e. carbonic anhydrase and citrate synthase) during protein refolding from GdmCl denaturation. Enzyme activity recovered in high ... |
14572728 | An efficient preparation of 6(I,IV) dihydroxy permethylated beta-cyclodextrin. | We report on a straightforward synthesis of 2(I-VII),3(I-VII),6(II,III,V-VII)-nonadeca-O-methylcyclomaltoheptaose, a methylated beta-cyclodextrin derivative bearing two 6(I,IV) hydroxyl groups, from its easily available benzylated counterpart. |
14570506 | Supramolecular assembly of dendritic polymers elucidated by 1H and 13C solid-state MAS NMR spectroscopy. | Advanced solid-state NMR methods under fast magic-angle spinning (MAS) are used to study the structure and dynamics of large supramolecular systems, which consist of a polymer backbone with dendritic side groups and self-assemble into a columnar structure. The NMR experiments are performed on as-synthesized samples, i.... |
14570492 | Controlling solubility and modulating peripheral function in dendrimer encapsulated dyes. | The synthesis of large dendrons and dendrimers with site-isolated dyes at their core has been explored. The dyes selected for this work were coumarin 343 and pentathiophene, as energy transfer processes prevail when the two dyes are intimately mixed but each should behave independently of the other if site-isolation is... |
14570491 | Simultaneous light emission from a mixture of dendrimer encapsulated chromophores: a model for single-layer multichromophoric organic light-emitting diodes. | The site isolation of two dyes capable of electronic interaction via Forster energy transfer has been studied with the two dyes coumarin 343 and pentathiophene encapsulated by dendrons containing both solubilizing and electroactive moieties. Photoluminescence studies of mixtures of the dendritic dyes show that at high ... |
14570489 | Highly cooperative formation of bis-urea based supramolecular polymers. | Eleven bis-ureas have been synthesized, and some of their properties are reported. Several of these compounds form supramolecular polymers in organic solvents. The self-association is shown by FTIR spectroscopy to display cooperativity at two levels. The first level of cooperativity is due to the synergistic associatio... |
14570486 | Hydroformylation reactions with recyclable rhodium-complexed dendrimers on a resin. | Rhodium-complexed dendrimers supported on a resin were evaluated as catalysts for the hydroformylation of aryl olefins and vinyl esters. The results showed the reactions proceeded very efficiently at room temperature with excellent yields. Outstanding selectivity for the branched aldehydes was also observed in all case... |
14570485 | Direct determination of the number of electrons needed to reduce coenzyme F430 pentamethyl ester to the Ni(I) species exhibiting the electron paramagnetic resonance and ultraviolet-visible spectra characteristic for the MCR(red1) state of methyl-coenzyme M reductase. | The UV-visible and electron paramagnetic resonance (EPR) spectra of MCR(red1), the catalytically active state of methyl-coenzyme M reductase, are almost identical to those observed when free coenzyme F430 or its pentamethyl ester (F430M) are reduced to the Ni(I) valence state. Investigations and proposals concerning th... |
14570461 | Supramolecular design for multivalent interaction: maltose mobility along polyrotaxane enhanced binding with concanavalin A. | High molecular mobility of maltose-conjugated alpha-cyclodextrins (alpha-CDs) along a poly(ethylene glycol) (PEG) chain due to the mechanically locked structure of polyrotaxanes enhanced multivalent interactions between maltose and concanavalin A (Con A). When maltose groups are conjugated with alpha-CDs that were thre... |
14570456 | Isolation, characterization, and reaction of activated iodosylbenzene monomer hydroxy(phenyl)iodonium ion with hypervalent bonding: supramolecular complex PhI+OH.18-crown-6 with secondary I...O interactions. | The isolation, characterization, and reaction of the active species hydroxy(phenyl)iodonium ion with hypervalent bonding are reported. Reaction of iodosylbenzene with HBF(4)-Me(2)O in the presence of equimolar 18-crown-6 in dichloromethane afforded the hydroxy-lambda(3)-iodane complex PhI(OH)BF(4).18-crown-6 as stable ... |
14570455 | Facile synthesis of a fullerene-barbituric acid derivative and supramolecular catalysis of its photoinduced dimerization. | A straightforward synthesis of a fullerene derivative appended with a barbituric acid molecular recognition motif is described. The presence of two nonself-complementary hydrogen-bonding sites is shown to be conducive to the construction of supramolecular assemblies. In the presence of a melamine derivative possessing ... |
14570109 | Characterization of microstructured optical fibers for wideband dispersion compensation. | Microstructured optical fibers (MOFs) with small hole-to-hole spacing and large airholes are designed to compensate the anomalous dispersion and the dispersion slope of single-mode fibers. The geometrical parameters that characterize triangular MOFs are chosen to optimize the fiber length and the compensation over a wi... |
14570049 | The nuclear pore complex: nucleocytoplasmic transport and beyond. | Over the past two years, it has become evident that there is an unexpected link between nuclear pore complex structure and dynamics, nucleocytoplasmic transport and chromosome segregation. In addition, a tomographic three-dimensional reconstruction of native nuclear pore complexes preserved in thick amorphous ice has u... |
14568981 | Intracellular recognition of lipopolysaccharide by toll-like receptor 4 in intestinal epithelial cells. | Toll-like receptor (TLR)4 has recently been shown to reside in the Golgi apparatus of intestinal crypt epithelial m-ICcl2 cells, colocalizing with internalized lipopolysaccharide (LPS). Here we demonstrate that disruption of the integrity of the Golgi apparatus significantly reduced LPS-mediated nuclear factor kappaB a... |
14566885 | Photoresponsive supramolecular systems: self-assembly of azodibenzoic acid linear tapes and cyclic tetramers. | A new strategy to effect photoinduced control over molecular self-assembly is reported. This strategy uses the reversible trans-cis photoisomerization of a novel azobenzene system, where the trans- and cis-forms self-assemble into dramatically different higher-order structures. The trans-azobenzene form of this molecul... |
14566877 | Selective recognition of configurational substates of zinc cyclam by carboxylates: implications for the design and mechanism of action of anti-HIV agents. | The interaction of metal cyclams with carboxylate groups is thought to play an important role in their binding to the CXCR4 chemokine receptor and in their anti-HIV activity. Here we report the synthesis of acetate, phthalate, perchlorate and chloride complexes of Zn(II) cyclam (1,4,8,11-tetraazacyclotetradecane). The ... |
14566871 | Synthesis, structure, and spectroscopy of phenylacetylenylene rods incorporating meso-substituted dipyrrin ligands. | The synthesis, structure, and spectroscopic characterization of a series of phenylacetylenylene rodlike molecules containing dipyrromethene (dipyrrin) ligands are described. The combination of the phenylacetylenylene groups with the porphyrinogenic dipyrrin moieties results in a rich absorption spectroscopy for these c... |
14566870 | Pyrrole-appended derivatives of O-confused oxaporphyrins and their complexes with nickel(II), palladium(II), and silver(III). | Condensation of 2,4-bis(phenylhydroxymethyl)furan with pyrrole and p-toluylaldehyde formed, instead of the expected 5,20-diphenyl-10,15-di(p-tolyl)-2-oxa-21-carbaporphyrin, a pyrrole addition product [(H,pyr)OCPH]H(2); this product can formally be considered as an effect of hydrogenation of 3-(2'-pyrrolyl)-5,20-dipheny... |
14566866 | In the twilight zone between [2]pseudorotaxanes and [2]rotaxanes. | A [2]pseudorotaxane, based on a semi-dumbbell-shaped component containing asymmetrically substituted monopyrrolotetrathiafulvalene and 1,5-dioxynaphthalene recognition sites for encirclement by cyclobis(paraquat-p-phenylene) and with a "speed bump" in the form of a thiomethyl group situated between the two recognition ... |
14566864 | Folding versus self-assembling. | Model foldable polymers with sequences of rigid hydrophobic chromophores and flexible hydrophilic tetra(ethylene glycol) were synthesized and used as a paradigm for studying molecular-folding and self-assembly phenomena. Our results demonstrate that intramolecular association or folding prevails over intermolecular int... |
14563549 | DNA transfer from chloroplast to nucleus is much rarer in Chlamydomonas than in tobacco. | By transforming chloroplasts with an antibiotic-resistance gene under the control of a nuclear-specific promoter, we employed a selection scheme to detect the transfer of DNA from the chloroplast to the nucleus in the green alga Chlamydomonas reinhardtii. Among several billion homoplasmic cells tested, we were unable t... |
14562391 | Parenteral versus early intrajejunal nutrition: effect on pancreatitic natural course, entero-hormones release and its efficacy on dogs with acute pancreatitis. | <h4>Aim</h4>To evaluate the effect of early intrajejunal nutrition (EIN) on the natural course, entero-hormone secretion and its efficacy on dogs with acute pancreatitis.<h4>Methods</h4>An acute pancreatitis model was induced by injecting 1 ml/kg of combined solution (2.5% sodium taurocholate and 8,000-10,000 BAEE unit... |
14562386 | Construction of expression systems for flaA and flaB genes of Helicobacter pylori and determination of immunoreactivity and antigenicity of recombinant proteins. | <h4>Aim</h4>To clone flagellin genes A (flaA) and B (flaB) from a clinical strain of Helicobacter pylori (H pylori) and to construct prokaryotic expression systems of the genes and identify immunity of the fusion proteins.<h4>Methods</h4>The flaA and flaB genes from a clinical H pylori isolate Y06 were amplified by hig... |
14561870 | Histone deacetylase inhibition by sodium butyrate chemotherapy ameliorates the neurodegenerative phenotype in Huntington's disease mice. | The precise cause of neuronal death in Huntington's disease (HD) is unknown. Although no single specific protein-protein interaction of mutant huntingtin has emerged as the pathologic trigger, transcriptional dysfunction may contribute to the neurodegeneration observed in HD. Pharmacological treatment using the histone... |
14561082 | Inclusion complexation and solubilization of paclitaxel by bridged bis(beta-cyclodextrin)s containing a tetraethylenepentaamino spacer. | A novel water-soluble paclitaxel complex has been prepared by inclusion complexation with bridged bis(beta-cyclodextrin)s and characterized by means of (1)H NMR, SEM, powder X-ray diffraction patterns, TG-DTA, DSC, FT-IR, and 2D NOESY. The cyclodextrins were able to solubilize paclitaxel to levels as high as 2 mg/mL. F... |
14562321 | Synthesis and supramolecular properties of trimethylene-bridged clips. | The novel trimethylene-bridged clips 3 and 4 have been synthesized by using repetitive stereoselective Diels-Alder reactions of the benzo- and naphthobismethylenenorbornenes 8 and 19 as dienes and norbornadiene 9 as bisdienophile, and subsequent dehydrogenation of the primary cyclobisadducts 10 and 20 by using 2,3-dich... |
14562319 | Synthesis of a hexagonal nanosized macrocyclic fluorophore with integrated endotopic terpyridine metal-chelation sites. | A rigid nanosized hexagonal phenylethynyl cyclophane 5 has been prepared, which incorporates two 2,2':6',2"-terpyridines as integral structural units, for the purpose of binding metal ions. Macrocycle 5 was obtained by a 14-step synthesis in an overall yield of 11 %, and was characterised by spectroscopic techniques. T... |
14562308 | Efficient transport of saccharides through a liquid membrane mediated by a cyclodextrin dimer. | A new efficient system for transporting saccharides through a liquid membrane has been constructed. The transport rates of saccharides were accelerated greatly by the cyclodextrin dimer 2; by contrast, the corresponding cyclodextrin monomer 1 was not effective at mediating saccharide transport. The transport rate of D-... |
14558844 | Highly emissive supramolecular oligo(p-phenylene vinylene) dendrimers. | pi-Conjugated oligo(p-phenylene vinylene) (OPV) guest molecules for interaction with dendritic hosts were synthesized and fully characterized by NMR spectroscopy, MALDI-TOF-MS, elemental analysis and optical measurements. The binding properties of the five different OPV guests to a N,N-bis[(3-adamantyl ureido) propyl] ... |
14558840 | Magnesium tetraarylporphyrin tweezer: a CD-sensitive host for absolute configurational assignments of alpha-chiral carboxylic acids. | A protocol to determine the absolute configuration of alpha-chiral carboxylic acids based on a modified circular dichroic (CD) exciton chirality method has been developed. The protocol relies on a host-guest complexation mechanism: the chiral substrates are derivatized to give bifunctional amide conjugates ("guests") t... |
14558796 | Assembly of a supramolecular cube, [(Cp*WS3Cu3)8 Cl8(CN)12Li4] from a preformed incomplete cubane-like compound [PPh4][Cp*WS3(CuCN)3]. | A supramolecular cube has been formed by linking WS3Cu3 clusters with bidentate ligands. Eight WS3Cu3 clusters, which have an incomplete cubane-like structure, serve as the three connecting nodes of the cube, while 12 bridging cyanide anions coordinated to copper centers lie along the edges of the cube. Eight chloride ... |
14558795 | Aqueous self-assembly of unsymmetric Peptide bolaamphiphiles into nanofibers with hydrophilic cores and surfaces. | Unsymmetric peptide bolaamphiphiles that incorporate (l-glutamyl)3glycine at one terminus and either tetraethylene glycol or aspartic acid at the other were found to form hydrogels at low wt %, presumably by self-assembling into nanofibers presenting (l-glutamyl)3glycine at their surfaces and burying the second headgro... |
14559103 | Biosensor profiling of molecular interactions in pharmacology. | Techniques employed to profile the pharmacological properties of a molecule in vitro normally require some type of radio-, enzymatic- or fluorescent-labeling of the ligand and/or the receptor. In contrast, biosensor techniques do not require labeling, and they allow virtually any complex to be screened with minimal ass... |
14558994 | Quartz crystal biosensor for real-time monitoring of molecular recognition between protein and small molecular medicinal agents. | A quartz crystal microbalance (QCM) biosensor integrated into a flow injection analysis (FIA) system was used for the real-time investigation of molecular recognition between a protein and small molecular medicinal agents. Two sulfa-drugs, sulfamethazine (SMZ) and sulfamethoxazole (SMO), were, respectively, immobilized... |
14559248 | Degranulation and superoxide production depend on cholesterol in PLB-985 cells. | The effect of agents disrupting cholesterol-rich microdomains of the cell membrane was studied on the chemoattractant receptor (FPR and FRPL1) coupled effector responses of promyelocytic PLB-985 cells. Both methyl-beta-cyclodextrin (MbetaCD) and filipin III inhibited exocytosis of primary granules and O(2)(.-) producti... |
14558696 | Differences in the methyl ester distribution of homogalacturonans from near-isogenic wheat lines resistant and susceptible to the wheat stem rust fungus. | Plants possess an efficient nonself surveillance system triggering induced disease resistance mechanisms upon molecular recognition of microbial invaders. Successful pathogens have evolved strategies to evade or counteract these mechanisms, e.g., by the generation of suppressors. Pectic fragments produced during host c... |
14558620 | Novel modes of capillary electrophoresis for the determination of endocrine disrupting chemicals. | The synthesis and usage of a wide range of organic chemicals has increased dramatically over the last five decades. These compounds sometimes termed endocrine disrupting chemicals include agricultural pesticides, industrial solvents, dyes, plasticisers, detergents and heat exchangers. Concerns have been raised about th... |
14558618 | Separation and characterization of humic acids from Antarctica by capillary electrophoresis and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Inclusion complexes of humic acids with cyclodextrins. | A new capillary electrophoresis procedure based on micellar electrokinetic capillary chromatography for the separation of humic acids (HAs) isolated from Antarctica soil was developed. The HAs were separated and characterized using a background electrolyte containing 0.09 M borate+0.09 M Tris+0.001 M EDTA (BTE) of pH 8... |
14558616 | Separation and on-line concentration of bisphenol A and alkylphenols by micellar electrokinetic chromatography with anionic surfactant. | Separation and on-line concentration of bisphenol A and three alkylphenols were investigated by micellar electrokinetic chromatography with the anionic surfactant, sodium dodecyl sulfate. The separation conditions were optimized by the simultaneous addition of the organic solvent and cyclodextrin to the running solutio... |
14558613 | Separation and identification of zaleplon metabolites in human urine using capillary electrophoresis with laser-induced fluorescence detection and liquid chromatography-mass spectrometry. | A capillary electrophoresis (CE) method using laser-induced fluorescence (LIF) detection for the determination of the hypnotic drug zaleplon and its metabolites in human urine could be developed using carboxymethyl-beta-cyclodextrin as a charged carrier. By the help of a complementary HPLC method coupled to mass spectr... |
14557290 | Role of Toll-like receptors in pathogen recognition. | The innate immune system relies on a vast array of non-clonally expressed pattern recognition receptors for the detection of pathogens. Pattern recognition receptors bind conserved molecular structures shared by large groups of pathogens, termed pathogen-associated molecular patterns. The Toll-like receptors (TLRs) are... |
14556907 | Photosystem I trimers from Synechocystis PCC 6803 lacking the PsaF and PsaJ subunits bind an IsiA ring of 17 units. | We report a structural characterization by electron microscopy and image analysis of a supramolecular complex consisting of Photosystem I (PSI) and the chlorophyll-binding protein IsiA from a mutant of the cyanobacterium Synechocystis PCC 6803 lacking the PsaF and PsaJ subunits. The circular complex consists of a centr... |
14552636 | Fine-tuning the weak-link approach: effect of ligand electron density on the formation of rhodium(I) and iridium(I) metallomacrocycles. | A novel bis(phosphinoalkyl-thioether)arene ligand with a fluorinated aryl group (1,4-(Ph(2)PCH(2)CH(2)S)(2)C(6)F(4)) has been synthesized. This ligand has been used to prepare symmetric bimetallic structures with Rh(I) and Ir(I) metal centers in high yield. Unlike their nonfluorinated counterparts, these complexes can ... |
14552632 | Synthesis and characterization of a new asymmetric bis-porphyrinato lanthanide complex presenting mixed hydrophilic-hydrophobic properties and its precursor form. | The synthesis and spectroscopic characterization of a new family of heteroleptic porphyrinate double-deckers are reported. The investigated compounds are represented by the formulae La(III)H(TPyP)(TPP) and [La(III)(TMePyP)(TPP)]I(3). UV-vis spectroscopy of the title complexes confirms the presence of a strong pi-pi int... |
14552630 | Synthesis of a copper [3]rotaxane able to function as an electrochemically driven oscillatory machine in solution, and to form SAMs on a metal surface. | Two new copper [3]rotaxanes have been synthesized. The axes are identical for both compounds and incorporate two bidentate chelates joined together by a disulfide bridge. The rings contain either the single phen (phen = 1,10-phenanthroline) chelate or two different chelates (phen and terpy; terpy = 2,2',6',2' '-terpyri... |
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