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11185620 | Dynamic modification of the capillary wall for electrophoretic separations of small ions. | Separations of small ions were carried out under nonequilibrated conditions using capillaries treated with NaOH, HCl, or tris(hydroxymethyl)aminomethane (Tris) prior to analysis. For separations of benzoic acid isomers or acids and amines under weakly acidic conditions, capillaries flushed with 0.1 M NaOH and subsequen... |
11185623 | Effect of mobile phase composition on the separation of propranolol enantiomers using a perphenylcarbamate beta-cyclodextrin bonded chiral stationary phase. | An analytical column packed with a novel perphenylcarbamate beta-cyclodextrin bonded chiral stationary phase was used to separate propranolol enantiomers. Good separation results were obtained using triethylammonium acetate (TEAA) buffer and methanol mixtures as the mobile phase. Effects of the methanol concentration, ... |
11185622 | New calixarene-bonded stationary phases in high-performance liquid chromatography: comparative studies on the retention behavior and on influences of the eluent. | The chromatographic behavior of six calixarene-bonded stationary phases is reported. Varying analyte selectivities (i.e., for phenols, substituted aromatics, polycyclic aromatic hydrocarbons, barbituric acid derivatives, xanthines) exist as a function of the ring-size of the calix[n]arenes (n=4, 6, 8) and the substitut... |
11185798 | Phthalocyanines in Langmuir and Langmuir-Blodgett films: from molecular design to supramolecular architecture. | A short review is given on Langmuir and Langmuir-Blodgett films containing phthalocyanine derivatives. A particular emphasis is directed towards the molecular parameters that can be clearly related to the supramolecular architecture observed at the air-water interface and within the LB multilayers. Several examples con... |
11154062 | Noncovalent binding of poly(ADP-ribose) to nuclear matrix proteins: developmental changes and tissue specificity. | Poly(ADP-ribose) is a nuclear polynucleotide involved in the regulation of chromatin functions via covalent and/or noncovalent modification of nuclear proteins. Using a binding assay on protein blots, we searched for poly(ADP-ribose) binding proteins in nuclear matrices from testes of differently aged rats as well as f... |
11152124 | Structural characterization of a mutant peptide derived from ubiquitin: implications for protein folding. | The formation of the N-terminal beta-hairpin of ubiquitin is thought to be an early event in the folding of this small protein. Previously, we have shown that a peptide corresponding to residues 1-17 of ubiquitin folds autonomously and is likely to have a native-like hairpin register. To investigate the causes of the s... |
11187467 | New metallodendrimers containing an octakis(diphenylphosphino)-functionalized silsesquioxane core and ruthenium(II)-based chromophores. | A new class of surface-modified dendrimers has been prepared by reactions of 8 equiv of the terpyridine-functionalized polyether monodendrons with a polyhedral oligomeric silsesquioxane (POSS) core. Subsequent reactions of these spherically shaped organic dendrimers with Ru(II)-based precursors afford photo- and redox-... |
11154564 | Macrocycle-supported titanium complexes with chelating imido ligands: analogues of ansa-metallocenes. | Reactions of 1,4-dimethyl-1,4,7-triazacyclononane (L1a) and 1,4-diisopropyl-1,4,7-triazacyclononane (L1b) to form 1-aminopropyl-4,7-di-R-1,4,7-triazacyclononane [R = Me (H2L3a) or Pri (H2L3b)] and 1-(2-aminobenzyl)-4,7-di-R-1,4,7-triazacyclononane [R = Me (H2L5a) or Pri (H2L5b)] are reported. Reaction of H2L3a and H2L5... |
11142508 | A method for incorporating dipolar couplings into structure calculations in cases of (near) axial symmetry of alignment. | A method for incorporating dipolar coupling restraints into structure calculations is described which follows closely on methodology that has been recently presented for orienting peptide planes using dipolar couplings [Mueller et al. (2000) J. Mol. Biol., 300, 197-212] and is specifically developed for use in cases of... |
11114072 | Survey of the 1999 surface plasmon resonance biosensor literature. | The application of surface plasmon resonance biosensors in life sciences and pharmaceutical research continues to increase. This review provides a comprehensive list of the commercial 1999 SPR biosensor literature and highlights emerging applications that are of general interest to users of the technology. Given the va... |
11114071 | Phage-displayed peptides as biosensor reagents. | This study investigated the potential to utilize phage-displayed peptides as reagents in sensor applications. A library of random 12-mers displayed on phage was panned against staphylococcal enterotoxin B (SEB), a causative agent of food poisoning. Nine SEB binding phage clones were isolated, all of which share the con... |
11114070 | Design, synthesis and evaluation of biomimetic affinity ligands for elastases. | A low-molecular-weight biomimetic affinity ligand selective for binding elastase has been designed and synthesized. The ligand was based on mimicking part of the interaction between a natural inhibitor, turkey ovomucoid inhibitor and elastase, and modelled from the X-ray crystallographic structure of the enzyme-inhibit... |
11114069 | New feature of angiotensin-converting enzyme: carbohydrate-recognizing domain. | Self carbohydrate-mediated dimerization of glycoprotein angiotensin-converting enzyme (ACE) was demonstrated. The dimerization was studied in the reverse micelle experimental system as a model of biomembrane situation. Asialo-ACE or agalacto-ACE was able to form a dimer, whereas deglycosylated ACE and sequentially desi... |
11114068 | Mimotopes: realization of an unlikely concept. | Theoretically it seems highly unlikely that relatively small peptides could mimic functionally discontinuous epitopes of antigens. Nevertheless various recent reports show this to be the case. Peptide mimics of protein-, polysaccharide- and DNA-epitopes have been shown to be able to replace the native epitope. Moreover... |
11114067 | Insight into protein structure and protein-ligand recognition by Fourier transform infrared spectroscopy. | An overview of the application of Fourier transform infrared spectroscopy for the analysis of the structure of proteins and protein-ligand recognition is given. The principle of the technique and of the spectra analysis is demonstrated. Spectral signal assignments to vibrational modes of the peptide chromophore, amino ... |
11131246 | Multiple organ failure--the discrepancy between our scientific knowledge and understanding and the management of our patients. | The excitement of molecular biology and of genetic knowledge and their possibilities must be balanced against our limitations in using this information for the care of our patients. There is a great discrepancy between what we know and what we can do. There are many reasons for this. A major one is that science must si... |
11129070 | Simultaneous chiral analysis of methamphetamine and related compounds by capillary electrophoresis. | A capillary electrophoretic method for the simultaneous chiral analysis of nine cationic drugs (18 enantiomers) has been developed. These drugs are methamphetamine (MA), amphetamine, dimethylamphetamine, ephedrine (EP), norephedrine, methylephedrine, 3,4-methylenedioxymethamphetamine, 3,4-methylenedioxyamphetamine and ... |
11126966 | Cyclodextrin dimers as receptor molecules for steroid sensors. | The dansyl-modified dimer 9 complexes strongly with the steroidal bile salts. Relative to native beta-cyclodextrin, the binding of cholate (1a) and deoxycholate (1b) salts is especially enhanced. These steroids bind exclusively in a 1:1 fashion. For other bile salts (1c-1e) both 1:1 and 1:2 complexes were observed with... |
11126962 | Affinity and nuclease activity of macrocyclic polyamines and their CuII complexes. | The stability constants of Cu(II) complexes that consist of either an oxaaza macrocycle with two triamine moieties linked by dioxa chains, or two macrocyclic ligands with a polyamine chain which are connecting the 2 and 9 positions of phenanthroline, have been determined by means of potentiometric measurements. The res... |
11126954 | Metal ligand aromatic cation-pi interactions in metalloproteins: ligands coordinated to metal interact with aromatic residues. | Cation-pi interactions between aromatic residues and cationic amino groups in side chains and have been recognized as noncovalent bonding interactions relevant for molecular recognition and for stabilization and definition of the native structure of proteins. We propose a novel type of cation-pi interaction in metallop... |
11126948 | Hierarchical self-organization of perylene bisimide--melamine assemblies to fluorescent mesoscopic superstructures. | A series of three perylene tetracarboxylic acid bisimide dyes 3a-c bearing phenoxy substituents at the four bay positions of the perylene core were synthesized and their complexation behavior to complementary ditopic dialkyl melamines 8a-c was investigated. Binding constants and Gibbs binding energies for the hydrogen ... |
11126947 | Metalloporphyrin molecular sieves. | Crystal-engineering strategies have been systematically developed for the rational design by self-assembly of diverse metalloporphyrin molecular-sieve materials. Cooperative coordination and hydrogen bonding algorithms of molecular recognition proved particularly useful for this aim. The supramolecular concepts used in... |
11130177 | The role of cholesterol in Shh signaling and teratogen-induced holoprosencephaly. | Holoprosencephaly, or an undivided forebrain, is a complex brain malformation associated with Sonic hedgehog (Shh) mutations. Other causes of holoprosencephaly have converged upon the Shh signaling pathway: genetic and pharmacologic impairment of cholesterol synthesis, and the action of the steroidal alkaloid cyclopami... |
11128592 | Host-guest complex formation in cyclotrikis-(1-->6). | The possibility that cyclotrikis-(1-->6)-[alpha-D-glucopyranosyl-(1-->4)-beta-D-glucopyranosyl] (CGM6) forms inclusion complexes, like cycloamyloses (cyclodextrins), was investigated by means of electrospray mass spectrometry and fluorescence spectroscopy. The complexing ability of both 1-anilinonaphthalene-8-sulfonate... |
11128588 | Crystal structures of heptakis(2,6-di-O-ethyl)cyclomaltoheptaose. | Heptakis(2,6-di-O-ethyl)-beta-cyclodextrin (DE-beta-CD) was crystallized in two forms from hexane and 95% aqueous methanol, respectively: A form I crystal with the space group P2(1)2(1)2(1) and a form II crystal with the space group P3(1). In both crystals, DE-beta-CD molecules are in a round shape with intramolecular ... |
11128288 | Tunable supramolecular synthons and versatile, water-soluble building blocks for crystal engineering:. | It is shown that the water-soluble dicarboxylic cationic acid [(eta5-C5H4COOH)2Co(III)]+ (1) is an extremely versatile building block for the construction of organometallic crystalline edifices. Removal of one proton from 1 leads to formation of the neutral zwitterion [(eta5-C5H4COOH)(eta5-C5H4COO)Co(III)] (2), while f... |
11128287 | Biomimetic copper(I)--CO complexes: a structural and dynamic study of a cali. | Four novel calix[6]arene-based cuprous complexes are described. They present a biomimetic tris(imidazole) coordination core associated with a hydrophobic cavity that wraps the apical binding site. Each differs from the other by the methyl or ethyl substituents present on the phenoxyl groups (OR1) and on the imidazole a... |
11128276 | Recognition-directed supramolecular assemblies of metal complexes of terpyridine derived ligands with self-complementary hydrogen bonding sites. | The synthesis and X-ray structures of three metal complexes with terpyridine-derived ligands that contain amino-pyrimidine and amino-pyrazine moieties are presented. They have been designed in view of directing their self-assembly into specific supramolecular arrays through molecular recognition interactions. The solid... |
11128274 | Ag+ labeling: a convenient new tool for the characterization of hydrogen-bonded supramolecular assemblies by MALDI-TOF mass spectrometry. | Herein we describe our results on the characterization of a wide variety of different hydrogen-bonded assemblies by means of a novel matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) technique with Ag+ labeling. The labeling technique with Ag+ ions is extremely mild and provide... |
11128222 | Preparation and evaluation of an imidazole-coated capillary column for the electrophoretic separation of aromatic acids. | An imidazole-coated capillary column for electrophoresis has been prepared by means of organosilanization. With mesityl oxide as neutral marker, the results indicated that the electroosmotic flow of the bonded phase displays a dramatic difference in pH dependence in comparison with that of the bare fused-silica column.... |
11128202 | Characterization of sulfobutyl ether-beta-cyclodextrins mixtures by anion-exchange chromatography using evaporative light scattering detection. | An analytical method based on anion-exchange chromatography (AEC) using volatile eluent ion and evaporative light scattering detection was developed for the analysis of mixtures of sulfobutyl-ether-beta-cyclodextrins (SBE-beta-CDs). A systematic investigation of the retention mechanism of pure SBE-beta-CD standards has... |
11126291 | Solid phase combinatorial synthesis of a library of macro-heterocycles and related acyclic compounds. | A solid phase synthesis of macrolactones from three building blocks and in eight steps is described. The synthesis which is carried out on the DHP resin includes Mitsunobu and DIC couplings. The macrocyclization occurs by SN2 displacement of an allylic chloride by a malonate anion. The synthetic methodology is suitable... |
11117512 | Acute effects of corticosterone on LiCl-induced rapid gustatory conditioning in rats: a taste reactivity analysis. | Previous research has shown that acute corticosterone treatment can have rapid effects on learning and memory. Using the taste reactivity test (TRT), the present study examined the effect of acute administration of corticosterone on sucrose palatability and the development of LiCl-induced rapid gustatory conditioning. ... |
11117324 | Molecular recognition of carbohydrates by a resorcinarene. Selective transport of alditols through a supported liquid membrane. | A supported liquid membrane (SLM) containing a resorcinarene carrier has been used for the selective transport of erythritol, threitol, ribitol and xylitol from concentrated (1.0-0.01 M) aqueous solutions. The membrane is made of a microporous polytetrafluoroethylene film impregnated with a 0.01 M solution of the carri... |
11127514 | Dynamics of autocatalytic replicator networks based on higher-order ligation reactions. | A class of autocatalytic reaction networks based on template-dependent ligation and higher-order catalysis is analysed. Apart from an irreversible ligation reaction we consider only reversible aggregation steps that provide a realistic description of molecular recognition. The overall dynamics can be understood by mean... |
11113279 | Inhibition of plasmin activity by sulfated polyvinylalcohol-acrylate copolymers. | The effect of four sulfated polyvinylalcohol-acrylate copolymers and heparin on plasminogen activation and on plasmin activity is studied. The molecules differing in charge (proportion of negatively charged units 40.5%-73.5% of the total) and in size (5600 Da-8800 Da) accelerate plasminogen activation by 2- up to 4-fol... |
11110175 | Diimide-enhanced fingerprint detection with photoluminescent CdS/dendrimer nanocomposites. | The chemical development of latent fingerprints by nanocomposites that involve photoluminescent cadmium sulfide nanoparticle aggregates with Starburst dendrimer is demonstrated. The dendrimer bonds to fingerprint residue via its terminal functional groups. When these are amino groups (generation 4 dendrimer), the bindi... |
11102064 | Calculating the local solvent chemical potential in crystal hydrates. | Determining solvation patterns in biological systems is crucial in investigating the functional role water may play in structural stabilization and molecular recognition. Determining whether a particular position would be occupied by a solvent molecule requires the local thermodynamics to be known. In this work we intr... |
11101228 | A fluorescence-based method for determining the surface coverage and hybridization efficiency of thiol-capped oligonucleotides bound to gold thin films and nanoparticles. | Using a fluorescence-based method, we have determined the number of thiol-derivatized single-stranded oligonucleotides bound to gold nanoparticles and their extent of hybridization with complementary oligonucleotides in solution. Oligonucleotide surface coverages of hexanethiol 12-mer oligonucleotides on gold nanoparti... |
11100721 | Coexistence of ferromagnetism and metallic conductivity in a molecule-based layered compound. | Crystal engineering--the planning and construction of crystalline supramolecular architectures from modular building blocks--permits the rational design of functional molecular materials that exhibit technologically useful behaviour such as conductivity and superconductivity, ferromagnetism and nonlinear optical proper... |
11090549 | Ignition of calcium sparks in arterial and cardiac muscle through caveolae. | Ca(2+) sparks are localized intracellular Ca(2+) events released through ryanodine receptors (RyRs) that control excitation-contraction coupling in heart and smooth muscle. Ca(2+) spark triggering depends on precise delivery of Ca(2+) ions through dihydropyridine (DHP)-sensitive Ca(2+) channels to RyRs of the sarcoplas... |
11093143 | Overlap of the anti-cardiolipin and anti-nucleosome responses of the (NZW X BXSB)F1 mouse strain: a new pattern of cross-reactivity for lupus-related autoantibodies. | The association of anti-nuclear antigen (ANA) and anti-cardiolipin (CL) antibodies is often observed during systemic lupus erythematosus (SLE) or the primary anti-phospholipid syndrome, thereby raising the possibility of a relationship between these two autoantibody populations. To determine whether ANA and anti-CL ant... |
11090817 | Vesicle reconstitution from lipid-detergent mixed micelles. | The process of formation of lipid vesicles using the technique of detergent removal from mixed-micelles is examined. Recent studies on the solubilization and reconstitution of liposomes participated to our knowledge of the structure and properties of mixed lipid-detergent systems. The mechanisms involved in both the li... |
11095301 | Interaction of 6-p-toluidinylnaphthalene-2-sulphonate with beta-cyclodextrin. | The present study examines the complexation of beta-cyclodextrin (beta-CD) with 6-p-toluidinylnaphthalene-2-sulfonate (TNS), a fluorescent probe for exploring hydrophobic regions of several biological substances. The complexation was monitored in aqueous solution by ultraviolet spectrophotometry. At first, the stoichio... |
11078519 | Molecular signals required for type III secretion and translocation of the Xanthomonas campestris AvrBs2 protein to pepper plants. | Strains of Xanthomonas campestris pv. vesicatoria (Xcv) carrying avrBs2 are specifically recognized by Bs2 pepper plants, resulting in localized cell death and plant resistance. Agrobacterium-mediated transient expression of the Xcv avrBs2 gene in plant cells results in Bs2-dependent cell death, indicating that the Avr... |
11069282 | A host-guest system to study structure-function relationships of membrane fusion peptides. | We designed a host-guest fusion peptide system, which is completely soluble in water and has a high affinity for biological and lipid model membranes. The guest sequences are those of the fusion peptides of influenza hemagglutinin, which are solubilized by a highly charged unstructured C-terminal host sequence. These p... |
11078529 | Physical reasons for the unusual alpha-helix stabilization afforded by charged or neutral polar residues in alanine-rich peptides. | We have carried out conformational energy calculations on alanine-based copolymers with the sequence Ac-AAAAAXAAAA-NH(2) in water, where X stands for lysine or glutamine, to identify the underlying source of stability of alanine-based polypeptides containing charged or highly soluble polar residues in the absence of ch... |
11069287 | Multiple quantum solid-state NMR indicates a parallel, not antiparallel, organization of beta-sheets in Alzheimer's beta-amyloid fibrils. | Senile plaques associated with Alzheimer's disease contain deposits of fibrils formed by 39- to 43-residue beta-amyloid peptides with possible neurotoxic effects. X-ray diffraction measurements on oriented fibril bundles have indicated an extended beta-sheet structure for Alzheimer's beta-amyloid fibrils and other amyl... |
11087855 | The design, synthesis, and evaluation of molecules that enable or enhance cellular uptake: peptoid molecular transporters. | Certain proteins contain subunits that enable their active translocation across the plasma membrane into cells. In the specific case of HIV-1, this subunit is the basic domain Tat(49-57) (RKKRRQRRR). To establish the optimal structural requirements for this translocation process, and thereby to develop improved molecul... |
11090135 | Preferential relaxation of positively supercoiled DNA by E. coli topoisomerase IV in single-molecule and ensemble measurements. | We show that positively supercoiled [(+) SC] DNA is the preferred substrate for Escherichia coli topoisomerase IV (topo IV). We measured topo IV relaxation of (-) and (+) supercoils in real time on single, tethered DNA molecules to complement ensemble experiments. We find that the preference for (+) SC DNA is complete ... |
11087341 | Synthesis of polyamidoamine dendrimers having poly(ethylene glycol) grafts and their ability to encapsulate anticancer drugs. | Polyamidoamine dendrimers having poly(ethylene glycol) grafts were designed as a novel drug carrier which possesses an interior for the encapsulation of drugs and a biocompatible surface. Poly(ethylene glycol) monomethyl ether with the average molecular weight of 550 or 2000 was combined to essentially every chain end ... |
11087328 | High-generation polycationic dendrimers are unusually effective at disrupting anionic vesicles: membrane bending model. | The membrane disruption properties of high generation (G4 to G7) poly(amidoamine) (PAMAM) dendrimers are evaluated and compared to linear poly(lysine). The G6 and G7 dendrimers are unusually effective at inducing leaky fusion of anionic, large unilamellar vesicles, as determined by standard fluorescence assays for lipi... |
11087950 | Design and realization of a tailor-made enzyme to modify the molecular recognition of 2-arylpropionic esters by Candida rugosa lipase. | Within a research project aimed at probing the substrate specificity and the enantioselectivity of Candida rugosa lipase (CRL), computer modeling studies of the interactions between CRL and methyl (+/-)-2-(3-benzoylphenyl)propionate (Ketoprofen methyl ester) have been carried out in order to identify which amino acids ... |
11089967 | An enantiomerically pure hydrogen-bonded assembly. | Chiral molecules have asymmetric arrangements of atoms, forming structures that are non-superposable mirror images of each other. Specific mirror images ('enantiomers') may be obtained either from enantiomerically pure precursor compounds, through enantioselective synthesis, or by resolution of so-called racemic mixtur... |
11086917 | Enantiomeric separation by cyclodextrin modified capillary zone electrophoresis (CD-CZE) of quaternary tetrahydroprotoberberine alkaloids. | A cyclodextrin modified capillary zone electrophoresis (CD-CZE) for the enantiomeric separation of tetrahydroprotoberberine N-metho salts was established. The resolution was optimized by changing the concentration of the electrolyte solution, hydroxypropyl-beta-CD (0.02 M, 0.07 M, or 0.14 M) or dimethyl-beta-CD (0.05 M... |
11086892 | Molecular orbital studies on pericyclic reactions of cinnamyl xanthates in beta-cyclodextrin cavities. | The solid beta-cyclodextrin (beta-CyD) complex of O-cinnamyl S-methyl dithiocarbonates (xanthate, 1a), upon heating at 45 degrees C, underwent asymmetric [3,31-sigmatropic rearrangement to give the optically S-(1-phenylallyl) S-methyl dithiocarbonate (2a) with 60% ee. Heating the beta-CyD complex of 2a at 120 degrees C... |
11086669 | Exercise rhabdomyolysis in military aircrew: two cases and a review of aeromedical disposition. | <h4>Introduction</h4>Exercise rhabdomyolysis (ER) is a rare, sometimes catastrophic condition where muscle fibers breakdown in response to exertion and release their breakdown products into the circulation. While ER was brought to the medical community's attention largely through reports from military training establis... |
11082013 | A novel synthesis of biaryl-containing macrocycles by a domino Miyaura arylboronate formation: intramolecular Suzuki reaction. | [reaction: see text] A novel macrocyclization procedure is developed on the basis of a domino process. Thus, treatment of linear diiodide 11 under defined conditions gave the 15-membered m,m-cyclophane 12 via aryl-aryl bond formation. Two distinct cross-coupling manifolds, Miyaura's arylboronic ester synthesis and intr... |
11080451 | The effect of the acidic tail on the DNA-binding properties of the HMG1,2 class of proteins: insights from tail switching and tail removal. | The high-mobility group (HMG) proteins HMG1, HMG2 and HMG2a are relatively abundant vertebrate DNA-binding and bending proteins that bind with structure specificity, rather than sequence specificity, and appear to play an architectural role in the assembly of nucleoprotein complexes. They have two homologous "HMG-box" ... |
11082108 | Pharmacology and autoradiography of human DP prostanoid receptors using [(3)H]-BWA868C, a DP receptor-selective antagonist radioligand. | 1. A potent and highly selective DP prostanoid receptor antagonist radioligand, [(3)H]-cyclohexyl-N-BWA868C (3-benzyl-5-(6-carboxyhexyl)-1-(2-cyclohexyl-2-hydroxyethyl-amino) hydantoin, ([(3)H]-BWA868C)), has been generated for receptor binding and autoradiographic studies. 2. Specific [(3)H]-BWA868C binding to human p... |
11078634 | Noninvasive methods for measuring and manipulating corticosterone in hummingbirds. | The adrenocortical response to stress has been shown to be important in energy management of vertebrates. Although hummingbirds (Trochilidae) are useful models for studying energy balance, they are not amenable to traditional methods of studying hormones. In this study we report noninvasive methods for measuring and ma... |
11081506 | A nanometre-scale electronic switch consisting of a metal cluster and redox-addressable groups. | So-called bottom-up fabrication methods aim to assemble and integrate molecular components exhibiting specific functions into electronic devices that are orders of magnitude smaller than can be fabricated by lithographic techniques. Fundamental to the success of the bottom-up approach is the ability to control electron... |
11076627 | Lithiation of meso-octamethylcalix[4]pyrrole: a general route to C-Rim monosubstituted calix[4]pyrroles. | Lithiation and subsequent addition of an electrophile to meso-octamethylcalix[4]pyrrole provides a straightforward synthetic route to new, C-rim monosubstituted calix[4]pyrroles. A variety of electrophiles were used, resulting in calix[4]pyrroles with appended functional groups including carboxyl, ester, iodo, and form... |
11076619 | Chiral recognition between a substituted cyclooctatetraene dianion and a half crown ether substituted with ibuprofen. | (S)-Verbenol was substituted onto cyclooctatetraene (COT) via an ether linkage. In tetrahydrofuran (THF), Cs(+) or Na(+) counterions are tightly ion associated with the verbenoxy-COT dianion. A cosolvent, consisting of an ibuprofen unit connected to a half crown ether, was added to the verbenoxy-COT(2)(-),M(+)(2) solut... |
11076582 | Structure-activity relationships in the acceleration of a hetero Diels-Alder reaction by metalloporphyrin hosts. | At 0.33 mM in dichloromethane at 25 degrees C the cyclic metalloporphyrin hosts 5, 7, 8, and 10 accelerate 12-fold, 260-fold, 1130-fold, and 250-fold, respectively, the reaction of 1 and 2 and also bind the product 3 very strongly. These observations combined with previously measured results with hosts 6, 9, and 11 all... |
11053125 | RYR1 and RYR3 have different roles in the assembly of calcium release units of skeletal muscle. | Calcium release units (CRUs) are junctions between the sarcoplasmic reticulum (SR) and exterior membranes that mediates excitation contraction (e-c) coupling in muscle cells. In skeletal muscle CRUs contain two isoforms of the sarcoplasmic reticulum Ca(2+)release channel: ryanodine receptors type 1 and type 3 (RyR1 and... |
11077304 | Marchantin M trimethyl ether. | The title macrocycle, C(31)H(30)O(5), is comprised of two bibenzyl ether moieties linked cyclically by spacers which each consist of two-carbon alkyl chains. The observed conformation of the macrocycle may be partly stabilized by intramolecular C-H.O close contacts. The packing appears to be directed by van der Waals f... |
11077302 | 25,27-(6-Tosyl-3,9-dioxa-6-azaundecane-1,11-diyldioxy)-26,28-(3,6, 9-trioxaundecane-1,11-diyldioxy)calix[4]arene. | A new calix[4]-crowned azacrown ether, C(51)H(59)NO(11)S, consisting of four phenyl rings in a 1,3-alternate conformation was synthesized from the reaction of 25, 27-bis(5-chloro-3-oxapentyloxy)calix[4]crown-5 and p-toluenesulfonamide in the presence of Cs(2)CO(3). A crown-5 loop was attached on the two facing lower ri... |
11077298 | Racemic 1,2-diphenylbut-3-yn-2-ol. | Molecules of the title compound, C(16)H(14)O, are chiral and crystallize in space group P-4 with Z' = 2, and with one R and one S molecule in the asymmetric unit. The conformations of the phenyl rings in the two independent molecules differ slightly. Supramolecular organization in the crystal is via tetrameric O-H. H(O... |
11077281 | Bis(1,5-diazacyclooctane-N,N')nickel(II) dibromide. | The crystal structure of the title complex, [Ni(C(6)H(14)N(2))(2)]Br(2), consists of discrete [Ni(C(6)H(14)N(2))(2)](2+) cations and bromide counter-anions. The Ni(II) ion is at the center of symmetry and is four-coordinated by four nitrogen donors of the mesocyclic ligand 1,5-diazacyclooctane (DACO) [Ni-N 1.935 (2)-1.... |
11076514 | Amyloid fibril formation by A beta 16-22, a seven-residue fragment of the Alzheimer's beta-amyloid peptide, and structural characterization by solid state NMR. | The seven-residue peptide N-acetyl-Lys-Leu-Val-Phe-Phe-Ala-Glu-NH(2), called A beta(16-22) and representing residues 16-22 of the full-length beta-amyloid peptide associated with Alzheimer's disease, is shown by electron microscopy to form highly ordered fibrils upon incubation of aqueous solutions. X-ray powder diffra... |
11073686 | Coordination-driven assembly of molecular rectangles via an organometallic "clip". | The combination of linear dipyridyl ligands with a new type of modular building unit, based upon a 1,8-platinum-functionalized anthracene, leads to the self-organization of rectangular frameworks. X-ray crystallography confirms the cyclic structure of the supramolecular cationic complexes. Spectral assignments were pro... |
11073662 | A rotaxane-like complex with controlled-release characteristics. | A rotaxane-like complex, based on a dumbbell-shaped component containing an NH(2)(+) recognition site for a [25]crown-8 ring component and a slippage stopper in the form of a p-(tert-butyl)phenyl group, has been synthesized by a "threading-followed-by-stoppering" approach. The half-life for dissociation of this complex... |
11073648 | Aryl phosphate complexation by cationic cyclodextrins. An enthalpic advantage for guanidinium over ammonium and unusual enthalpy-entropy compensation. | The enthalpies and entropies for phosphate complexation by ammonium and guanidinium groups have been compared using cationic cyclodextrins. Aryl phosphate binding by guanidinium hosts is associated with more favorable enthalpies and less favorable entropies, consistent with the idea that guanidinium-phosphate interacti... |
11073612 | Porphyrins with exocyclic rings. 15.(1) synthesis of quino- and isoquinoporphyrins, aza analogues of the naphthoporphyrins. | Porphyrins with fused isoquinoline and quinoline units have been prepared by the "3 + 1" methodology. 5-Nitroisoquinoline and 6-nitroquinoline condensed with ethyl isocyanoacetate in the presence of a phosphazene base to give isoquino- and quinopyrroles, respectively. Ester saponification and decarboxylation with KOH i... |
11073599 | Rational synthesis of beta-substituted chlorin building blocks. | Chlorins bearing synthetic handles at specific sites about the perimeter of the macrocycle constitute valuable building blocks. We previously developed methodology for preparing meso-substituted chlorin building blocks and now present methodology for preparing several complementary beta-substituted chlorin building blo... |
11078207 | Modulation of the Cs2CO3-promoted catalytic amination by a crown ether. | The catalytic addition of 18-Crown-6 in some Cs2CO3-promoted amination of triflates and bromides was beneficial to improve sluggish reaction with suppression of the unwanted side products. The protocol was useful for the preparation of chlorinated aryl piperazines from phenol derivatives. |
11075311 | Comparative population pharmacokinetic-pharmacodynamic analysis for piroxicam-beta-cyclodextrin and piroxicam. | Piroxicam (Feldene) is indicated for osteoarthritis and rheumatoid arthritis but not analgesia due to its delayed onset of pain relief. Piroxicam-beta-cyclodextrin (PBCD) was developed for pain indication by virtue of the increased absorption rate of piroxicam. Forty-eight patients received a single dose of PBCD or Fel... |
11072107 | Peptide nucleic acids: versatile tools for gene therapy strategies. | Peptide nucleic acids, or PNAs, are oligonucleotide analogs in which the phosphodiester backbone is replaced with a polyamide structure. First synthesized less than 10 years ago, they have received great attention due to their several favorable properties, including resistance to nuclease and protease digestion, stabil... |
11071807 | Two DNA-binding sites on the globular domain of histone H5 are required for binding to both bulk and 5 S reconstituted nucleosomes. | We have previously shown the existence of two DNA-binding sites on the globular domain of H5 (termed GH5), both of which are required for nucleosome organisation, as judged by the protection of a 166 bp chromatosome intermediate during micrococcal nuclease digestion of chromatin. This supports a model in which GH5 cont... |
11071914 | The yeast nucleoporin Nup53p specifically interacts with Nic96p and is directly involved in nuclear protein import. | The bidirectional nucleocytoplasmic transport of macromolecules is mediated by the nuclear pore complex (NPC) which, in yeast, is composed of approximately 30 different proteins (nucleoporins). Pre-embedding immunogold-electron microscopy revealed that Nic96p, an essential yeast nucleoporin, is located about the cytopl... |
11071908 | A nonerythroid isoform of protein 4.1R interacts with components of the contractile apparatus in skeletal myofibers. | The approximately 80-kDa erythroid 4.1R protein is a major component of the erythrocyte cytoskeleton, where it links transmembrane proteins to the underlying spectrin/actin complexes. A diverse collection of 4.1R isoforms has been described in nonerythroid cells, ranging from approximately 30 to approximately 210 kDa. ... |
11075686 | Vibrational and theoretical study of the 2',6'-dimethoxyflavone cis-formic acid inclusion compound. | The FT-infrared and Raman microscopy spectra of the 2',6'-dimethoxyflavone and its 1:1 complex with formic acid in solid state have been recorded and analysed. Some vibrational components appear as specific to the cis-rotamer of formic acid in the crystalline sample, especially the CH group stretching vibration feature... |
11069935 | Associative long-term depression in the hippocampus is dependent on postsynaptic N-type Ca2+ channels. | Long-term depression (LTD) is a form of synaptic plasticity that can be induced either by low-frequency stimulation of presynaptic fibers or in an associative manner by asynchronous pairing of presynaptic and postsynaptic activity. We investigated the induction mechanisms of associative LTD in CA1 pyramidal neurons of ... |
11050164 | Condensed complexes, rafts, and the chemical activity of cholesterol in membranes. | Epifluorescence microscopy studies of mixtures of phospholipids and cholesterol at the air-water interface often exhibit coexisting liquid phases. The properties of these liquids point to the formation of "condensed complexes" between cholesterol and certain phospholipids, such as sphingomyelin. It is found that monola... |
11070074 | Emergent mechanical properties of self-assembled polymeric capsules. | Synthetic self-assembled systems combine responsiveness and reversibility with the ability to perform chemical tasks such as molecular recognition and catalysis. An unmet challenge is the construction of polymeric materials that, like nature's tubulin, are simultaneously reversible and capable of useful physical tasks.... |
11068200 | Fibrillin: from domain structure to supramolecular assembly. | In the last 5 years, significant progress has been made in understanding the structure and function of all the major domains composing the fibrillins. A previous review [Meth. Enzymol. 245 (1994), 29] focused on the isolation of fibrillin monomers and fibrillin-containing polymers (microfibrils). In this article, infor... |
11067874 | Immunosuppression and resultant viral persistence by specific viral targeting of dendritic cells. | Among cells of the immune system, CD11c(+) and DEC-205(+) splenic dendritic cells primarily express the cellular receptor (alpha-dystroglycan [alpha-DG]) for lymphocytic choriomeningitis virus (LCMV). By selection, strains and variants of LCMV that bind alpha-DG with high affinity are associated with virus replication ... |
11067870 | The bile acid synthetic gene 3beta-hydroxy-Delta(5)-C(27)-steroid oxidoreductase is mutated in progressive intrahepatic cholestasis. | We used expression cloning to isolate cDNAs encoding a microsomal 3beta-hydroxy-Delta(5)-C(27)-steroid oxidoreductase (C(27) 3beta-HSD) that is expressed predominantly in the liver. The predicted product shares 34% sequence identity with the C(19) and C(21) 3beta-HSD enzymes, which participate in steroid hormone metabo... |
11069586 | The Calliphora rpa mutant lacks the PDZ domain-assembled INAD signalling complex. | The visual transduction cascade of fly photoreceptors is a G protein-coupled phospholipase C-signalling pathway which is assembled into a supramolecular signalling complex by the PDZ (postsynaptic density protein-95, discs large, Z0-1) domain protein INAD (inactivation no afterpotential D). The norpA-encoded phospholip... |
11068697 | Nimesulide and beta-cyclodextrin inclusion complexes: physicochemical characterization and dissolution rate studies. | Complex formation of nimesulide (N) and beta-cyclodextrin (beta CD) in aqueous solution and in solid state and the possibility of improving the solubility and dissolution rate of nimesulide via complexation with beta CD were investigated. Phase solubility studies indicated the formation of a 1:1 complex in solution. Th... |
11068687 | Effect of water-soluble carriers on dissolution characteristics of nifedipine solid dispersions. | Solid dispersions of nifedipine (NP) with polyethylene glycols (PEG4000 and PEG6000), hydroxypropyl-beta-cyclodextrin (HP beta CD), and poloxamer 407 (PXM 407) in four mixing ratios were prepared by melting, solvent, and kneading methods in order to improve the dissolution of NP. The enhancement of the dissolution rate... |
11064210 | DNA transfection and transfected cell viability using amphipathic asymmetric dendrimers. | Amphipathic asymmetric dendrimers have been investigated for use in delivery of genes into cells, with the objective of optimising transfection efficiency and maintaining cell viability. We have synthesised amphipathic asymmetric dendrimers by solid phase methods. The ability of two of these to transfect BHK cells in c... |
11064130 | Self-assembled hydrogel nanoparticles from curdlan derivatives: characterization, anti-cancer drug release and interaction with a hepatoma cell line (HepG2). | Self-assembled hydrogel nanoparticles were synthesized from carboxymethylated (CM)-curdlan, substituted with a sulfonylurea (SU) as a hydrophobic moiety for self-assembly. The degree of SU substitution was 2.4, 5.6, or 7.2 SU groups per hundred anhydroglucose units of curdlan. The physicochemical properties of the self... |
11063617 | Inhibition of protein synthesis by didemnins: cell potency and SAR. | Synthetic and naturally occurring didemnins are potent and specific inhibitors of protein synthesis in vitro. Structure-activity analysis indicates a requirement for the intact macrocycle; however, the smaller ring size represented by the didemnin analogue, tamandarin A, is equipotent to didemnin B. Replacement of the ... |
10944530 | Permeabilization via the P2X7 purinoreceptor reveals the presence of a Ca2+-activated Cl- conductance in the apical membrane of murine tracheal epithelial cells. | Calcium-activated Cl(-) secretion is an important modulator of regulated ion transport in murine airway epithelium and is mediated by an unidentified Ca(2+)-stimulated Cl(-) channel. We have transfected immortalized murine tracheal epithelial cells with the cDNA encoding the permeabilizing P2X(7) purinoreceptor (P2X(7)... |
11063707 | GL3 encodes a bHLH protein that regulates trichome development in arabidopsis through interaction with GL1 and TTG1. | Arabidopsis trichome development and differentiation is a well-studied model for plant cell-fate determination and morphogenesis. Mutations in TRANSPARENT TESTA GLABRA1 (TTG1) result in several pleiotropic defects including an almost complete lack of trichomes. The complex phenotype caused by ttg1 mutations is suppress... |
11063682 | Self-compatible B mutants in coprinus with altered pheromone-receptor specificities. | A successful mating in the mushroom Coprinus cinereus brings together a compatible complement of pheromones and G-protein-coupled receptors encoded by multiallelic genes at the B mating-type locus. Rare B gene mutations lead to constitutive activation of B-regulated development without the need for mating. Here we char... |
11061967 | Molecular-level thermodynamic and kinetic parameters for the self-assembly of apoferritin molecules into crystals. | The self-assembly of apoferritin molecules into crystals is a suitable model for protein crystallization and aggregation; these processes underlie several biological and biomedical phenomena, as well as for protein and virus self-assembly. We use the atomic force microscope in situ, during the crystallization of apofer... |
11060011 | The structure of the mRNA export factor TAP reveals a cis arrangement of a non-canonical RNP domain and an LRR domain. | Human TAP is implicated in mRNA nuclear export and is used by simian type D retroviruses to export their unspliced genomic RNA to the cytoplasm of the host cell. We have determined the crystal structure of the minimal TAP fragment that binds the constitutive transport element (CTE) of retroviral RNAs. Unexpectedly, we ... |
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