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14622277 | Interactions of the peripheral subunit-binding domain of the dihydrolipoyl acetyltransferase component in the assembly of the pyruvate dehydrogenase multienzyme complex of Bacillus stearothermophilus. | The enzymes pyruvate decarboxylase (E1) and dihydrolipoyl dehydrogenase (E3) bind tightly but in a mutually exclusive manner to the peripheral subunit-binding domain (PSBD) of dihydrolipoyl acetyltransferase in the pyruvate dehydrogenase multienzyme complex of Bacillus stearothermophilus. The use of directed mutagenesi... |
14623280 | Bifunctional DNA-gold nanoparticle conjugates as building blocks for the self-assembly of cross-linked particle layers. | The DNA-directed self-assembly of surface-bound layers of gold nanoparticles offers a broad range of applications in biomedical analyses as well as in materials science. We here describe a new concept for the assembly of substrate-bound nanoparticle monolayers which employs bifunctional nanoparticles as building blocks... |
14623400 | Collagens--structure, function, and biosynthesis. | The extracellular matrix represents a complex alloy of variable members of diverse protein families defining structural integrity and various physiological functions. The most abundant family is the collagens with more than 20 different collagen types identified so far. Collagens are centrally involved in the formation... |
14622027 | Functionalized fullerenes in water. The first 10 years of their chemistry, biology, and nanoscience. | Fullerenes are entirely insoluble in water, but suitable functionalization makes the molecules soluble. Studies on water-soluble fullerene derivatives led to the discovery of the interaction of organofullerenes with DNA, proteins, and living cells, which was first reported in the summer of 1993. Subsequent studies have... |
14617359 | Cholesterol loading induces a block in the exit of VSVG from the TGN. | Recent work from our laboratory demonstrated that increased cellular cholesterol content affects the structure of the Golgi apparatus. We have now investigated the functional consequences of the cholesterol-induced vesiculation of the Golgi apparatus and the role of actin for these changes. The results showed that chol... |
14616012 | CE/electrospray ionization-MS analysis of underivatized d/l-amino acids and several small neurotransmitters at attomole levels through the use of 18-crown-6-tetracarboxylic acid as a complexation reagent/background electrolyte. | A new capillary electrophoresis/mass spectrometry technique is introduced for attomole detection of primary amines (including several neurotransmitters), amino acids, and their d/l enantiomers in one run through the use of a complexation reagent while using only approximately 1 nL of sample. The technique uses underiva... |
14616006 | Investigation of cocaine plumes using surface acoustic wave immunoassay sensors. | Vapor sensors, aka electronic noses, are becoming an increasingly popular analytical tool for detection and identification of small molecules in the gas phase. In this paper, we present the results of a series of experiments demonstrating real-time vapor phase detection of cocaine molecules. A distinctive response or s... |
14616000 | Carbon nanotubes as assisted matrix for laser desorption/ionization time-of-flight mass spectrometry. | Analysis of low molecular weight compounds with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) has been developed by using carbon nanotubes obtained from coal by arc discharge as the matrix. The carbon nanotube matrix functions as substrate to trap analytes of peptides, organ... |
14615978 | Direct observation of molecular recognition mediated by triple hydrogen bonds at a water/oil interface: time-resolved total internal reflection fluorometry study. | Molecular recognition mediated by hydrogen-bonding interactions at a water/CCl(4) interface was investigated directly by means of time-resolved total internal reflection (TIR) fluorescence spectroscopy. The TIR fluorescence decay profile of riboflavin (RF) in the absence of a guest in the CCl(4) phase was fitted satisf... |
14619437 | [Influenza-associated encephalopathy--pathophysiology and disease mechanisms]. | From the middle of 1990's, there repeated in winter season an outbreak of encephalopathy in Japan that appeared to be associated with influenza. A national survey was conducted, and a total of 507 patients was diagnosed as having influenza-associated encephalopathy during 1998-2002 on the basis of virologic analysis. T... |
14611258 | Porphyrazines with annulated diazepine rings. 2. Alternative synthetic route to tetrakis-2,3-(5,7-diphenyl-1,4-diazepino)porphyrazines: new metal complexes, general physicochemical data, ultraviolet-visible linear and optical limiting behavior, and electrochemical and spectroelectrochemical properties. | Following a previous report on the synthesis and physicochemical characterization of a novel class of porphyrazines carrying peripherally annulated seven-membered rings, i.e., tetrakis-2,3-(5,7-diphenyl-1,4-diazepino)porphyrazine [Ph(8)DzPzH(2)].4H(2)O and its metal derivatives [Ph(8)DzPzM].xH(2)O (x = 2-7, M = Mg(II)(... |
14611257 | Molecular acrobatics: self-assembly of calixarene-porphyrin cages. | Calix[4]arenes equipped with two and four zinc porphyrins have been prepared, and they show remarkable flexibility in their self-assembly properties with the bidentate ligand DABCO. The calix-bisporphyrin forms a 2:2 complex with DABCO, generating a large cavity that has the potential to act as a supramolecular host. T... |
14611256 | Metal-core--organic shell dendrimers as unimolecular micelles. | The synthesis and characterization of nanoparticle-cored dendrimers (NCDs), consisting of a metal core capped by arylpolyethers terminated with ester or carboxylate groups, are reported. These NCDs, comprising nanometer-sized gold clusters at the core and organic dendrons radially connected to the gold core by gold-sul... |
14611234 | Kinetic evidence for the existence and mechanism of formation of a barrel stave structure from pore-forming dendrimers. | A dendritic approach to the construction of a homologous series of pore-forming amphiphiles has been developed, based on the use of spermidine, spermine, lysine, and cholic acid. A kinetic analysis of Na+ transport across bilayers of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine by three dendritic amphiphiles has pr... |
14611218 | Facile self-assembly of predesigned neutral 2D pt-macrocycles via a new class of rigid oxygen donor linkers. | Self-assembly of rigid oxygen donor dicarboxylates such as terephthalate and fumarate with a platinum-containing clip-like acceptor unit afforded neutral macrocyclic rectangles which have been characterized by X-ray single-crystal structure analysis as well as NMR spectroscopy. |
14611211 | Molecular recognition and conductance in crown ethers. | Crown ethers have the remarkable property of recognizing and binding specific metal cations in complex mixtures. We propose to combine molecular recognition with molecular electric conductance. The question we address is: can the event of binding a cation be sensed by a change in conductance? Specifically, we study a s... |
14611210 | Supramolecular peapods composed of a metalloporphyrin nanotube and fullerenes. | An acyclic dimer of a dendritic zinc porphyrin bearing six carboxylic acid functionalities (1acid) interacts with fullerenes, such as C60 and C70, to form "supramolecular peapods", composed of a hydrogen-bonded zinc porphyrin nanotube and fullerenes (3). According to TEM, the peapods are very long (>1 mum) and have a u... |
14611204 | Multistimuli, multiresponsive metallo-supramolecular polymers. | The use of metal ion-induced polymerizations of a ditopic ligand offers a facile route to the preparation of organic/inorganic hybrid materials. Such metallo-supramolecular polymers potentially offer the functionality of the metal ion along with the processibility of a polymer. We report, herein, the preparation of gel... |
14611180 | Stability of natamycin and its cyclodextrin inclusion complexes in aqueous solution. | Aqueous solutions of natamycin and its beta-cyclodextrin (beta-CD), hydroxypropyl beta-cyclodextrin, and gamma-cyclodextrin (gamma-CD) inclusion complexes were completely degraded after 24 h of exposure to 1000 lx fluorescent lighting at 4 degrees C. After 14 days of storage in darkness at 4 degrees C, 92.2% of natamyc... |
14611179 | Formation of natamycin:cyclodextrin inclusion complexes and their characterization. | Natamycin is a broad spectrum antimycotic with very low water solubility, which is used to extend the shelf life of shredded cheese products. beta-Cyclodextrin (beta-CD), hydroxypropyl beta-cyclodextrin (HP beta-CD), and gamma-cyclodextrin (gamma-CD) were found to form inclusion complexes with natamycin in aqueous solu... |
14611176 | Enantioselective analysis of methyl-branched alcohols and acids in rhubarb (Rheum rhabarbarum L.) stalks. | The enantiomeric compositions of 2-methylbutanol (1), 4-methylhexanol (2), 2-methylbutanoic acid (3), and 4-methylhexanoic acid (4) present in rhubarb (Rheum rhabarbarum L.) stalks were determined. Enantiodifferentiation was achieved via multidimensional gas chromatography using heptakis(2,3,6-tri-O-ethyl)-beta-cyclode... |
14613210 | Hybrid microdevice electrophoresis of peptides, proteins, DNA, viruses, and bacteria in various separation media, using UV-detection. | Recently we described the design of a hybrid microdevice for micro(nano)electrophoresis and electrochromatography, discussed its advantages and disadvantages compared to conventional microdevices and presented a few applications with low-molecular-weight samples. In this paper, we demonstrate the broad application rang... |
14613197 | Improved solid-phase microextraction device for use in on-line immunoaffinity capillary electrophoresis. | A simple solid-phase microextraction device was fabricated for use in on-line immunoaffinity capillary electrophoresis (CE). The device, designed in the form of a four-part cross-shaped or cruciform configuration, includes a large-bore tube to transport samples and washing buffers and a small-bore fused-silica capillar... |
14613149 | Investigation of the origin of selectivity in cavitand-based supramolecular sensors. | The sensing properties of functionalized cavitands have been studied by thin-film coating TMSR chemical sensors and by measuring their responses towards model analytes. We studied the relationship between the sensor performance, in terms of sensitivity and selectivity, and the molecular recognition properties of the ca... |
14613145 | Controlling multivalent interactions in triply-threaded two-component superbundles. | We have investigated the (1)H NMR spectra, the absorption spectra, the fluorescence spectra and decays, and the electrochemical properties of i). a tritopic receptor in which three benzo[24]crown-8 macrorings are fused onto a triphenylene core, ii). a trifurcated trication wherein three dibenzylammonium ions are linked... |
14613133 | Effect of chirality on the structural behaviour of hydrogen-bonded n-alkylammonium pyroglutamates in the crystalline and smectic state. | A set of optically active and racemic n-alkylammonium pyroglutamates from dodecyl to octadecyl were synthesized and characterised. Their thermotropic polymorphism was investigated by polarizing optical microscopy, differential scanning calorimetry and dilatometry. Their structure in the crystalline and smectic state wa... |
14613130 | Synthesis and characterization of carboxylate complexes of Sn(IV) porphyrin monomers and oligomers. | Most of the porphyrin-recognition chemistry we have investigated previously has centred on kinetically labile metal-ligand interactions, such as Z-N and Ru-N. Our interest in the broader scope of molecular recognition required a metal with the ability to specifically recognise non-nitrogen-based ligands, with a signifi... |
14613128 | Trimeric perfluoro-ortho-phenylenemercury: a versatile Lewis acidic host. | Trimeric perfluoro-ortho-phenylenemercury (1) constitutes one of the simplest trifunctional Lewis acidic hosts. In addition to cooperative effects arising from the proximity of the mercury(II) centers, the electron-withdrawing properties of the backbone and the accessibility of the electrophilic sites lead to the facil... |
14613127 | Resorcinarenes as templates. | Metal ions are superb at templating the synthesis of small macrocycles that are decorated with Lewis basic sites. However, for the synthesis of larger macrocycles, or the synthesis of macrocycles devoid of an array of Lewis basic sites, metal ions are less useful. Here we demonstrate that resorcinarenes can be used as ... |
14609946 | Dimerization controls the lipid raft partitioning of uPAR/CD87 and regulates its biological functions. | The urokinase-type plasminogen activator receptor (uPAR/CD87) is a glycosylphosphatidylinositol-anchored membrane protein with multiple functions in extracellular proteolysis, cell adhesion, cell migration and proliferation. We now report that cell surface uPAR dimerizes and that dimeric uPAR partitions preferentially ... |
14609342 | Mechanism-based inactivation of thioredoxin reductase from Plasmodium falciparum by Mannich bases. Implication for cytotoxicity. | Thioredoxin reductase (TrxR) is the homodimeric flavoenzyme that catalyzes reduction of thioredoxin disulfide (Trx). For Plasmodium falciparum, a causative agent of tropical malaria, TrxR is an essential protein which has been validated as a drug target. The high-throughput screening of 350000 compounds has identified ... |
14609336 | Exposure of phosphatidylinositol transfer proteins to sphingomyelin-cholesterol membranes suggests transient but productive interactions with raft-like, liquid-ordered domains. | Both isoforms of rat phosphatidylinositol transfer protein (PITP) mediate the intermembrane transfer of sphingomyelin (CerPCho). In the plasma membrane, CerPCho often segregates with cholesterol into microdomains such as lipid rafts and caveolae. To test the hypothesis that PITP exhibits a preference for CerPCho- and c... |
14606863 | Two novel vanadium tellurites covalently bonded with metal-organic complex moieties: M(phen)V(2)TeO(8) (M = Cu, Ni). | Two novel two-dimensional organic-inorganic hybrid vanadium tellurites M(phen)V(2)TeO(8) (M = Cu (1), Ni (2)) have been hydrothermally synthesized and characterized by the elemental analyses, IR spectra, EPR spectrum, XPS spectra, TG analyses, and single-crystal X-ray diffraction. Compound 1 crystallizes in the monocli... |
14606859 | Molecular metamagnet [Ni(4ImNNH)(2)(NO(3))(2)] (4ImNNH = 4-imidazolyl nitronyl nitroxide) and the related compounds showing supramolecular H-bonding interactions. | A new chelating radical ligand 4ImNNH (2-(4-imidazolyl)-4,4,5,5-tetramethylimidazolin-1-oxyl 3-oxide) was prepared, and complexation with divalent transition metal salts gave complexes, [M(4ImNNH)(2)X(2)], which showed intermolecular ferromagnetic interaction in high probability (7 out of 10 paramagnetic compounds inve... |
14606857 | Chemistry of constrained dioxocyclam ligands with Co(III): unusual examples of C-H and C-N bond cleavage. | The reactions between H(2)dc3 and Co(acac)(3) have been studied in the presence and absence of base. In the presence of base, a complex with an intramolecular Co-C bond, Co(dc3-C-(8))(H(2)O), 1, is formed, presumably through heterolytic C-H bond activation. An X-ray crystallographic study demonstrates the presence of a... |
14606848 | A porous supramolecular architecture from a copper(II) coordination polymer with a 3D four-connected 8(6) net. | A novel coordination polymer [[Cu(L(1))(L(2))(H(2)O)].5H(2)O](n) (1), where L(1) =1,1'-(1,4-butanediyl)bis(imidazole) and L(2) = m-phthalate anion, has been obtained by using an unusual crystallization process. It crystallizes in the orthorhombic space group Pna2(1), which belongs to the crystal class mm2, with a = 9.0... |
14606846 | Novel silver-containing supramolecular frameworks constructed by combination of coordination bonds and supramolecular interactions. | The hydrothermal reactions of AgNO(3), 4,4'-bipy, and carboxylate ligands gave rise to three supramolecular architectures, namely [Ag(bipy)].H(2)SIPA.1/2bipy.H(2)O (1), [Ag(bipy)].1/2H(2)btec.H(2)O (2), and [Ag(bipy)](2).H(2)dpstc.2H(2)O (3) (H(3)SIPA = 5-sulfoisophthalic acid, bipy = 4,4'-bipyridine, H(4)btec = 1,2,4,... |
14606839 | Synthesis and characterization of bis(S-acetylthio)-derivatized europium triple-decker monomers and oligomers. | We report the synthesis of monomers, dimers, trimers, and oligomers of triple-decker (TD) complexes bearing S-acetylthio groups at the termini: AcS-(TD)(n)()-SAc. Each TD was of type (Pc)Eu(Pc)Eu(Por), where H(2)Pc = tetra-tert-butylphthalocyanine and H(2)Por is a meso-tetraarylporphyrin bearing functional groups at th... |
14606820 | Synthesis, characterization, and autoreduction of a highly electron-deficient porphycenatoiron(III) with trifluoromethyl substituents. | The synthesis of the first fluorine-containing iron porphycenes, 2,7,12,17-tetraethyl-3,6,13,16-tetrakis(trifluoromethyl)porphycenatoiron(III) chloride [FePc(EtioCF(3))]Cl and its micro-oxo dimer [FePc(EtioCF(3))](2)O and their characterizations are reported. The crystal structure of [FePc(EtioCF(3))](2)O displays a se... |
14606905 | Synthesis and aqueous solution properties of novel sugar methacrylate-based homopolymers and block copolymers. | We report the facile preparation of a range of novel, well-defined cyclic sugar methacrylate-based polymers without recourse to protecting group chemistry. 2-Gluconamidoethyl methacrylate (GAMA) and 2-lactobionamidoethyl methacrylate (LAMA) were prepared directly by reacting 2-aminoethyl methacrylate with D-gluconolact... |
14606519 | Enamel structure properties controlled by engineered proteins in transgenic mice. | <h4>Unlabelled</h4>Amelogenin protein has regulatory effects on enamel biofabrication in mammalian tooth. Using teeth obtained from transgenic mice that express two separate protein-engineered versions of amelogenins, we made structure-nanomechanical properties correlations and showed 21% hardness and 24% elastic modul... |
14606062 | Gene therapy for gastric cancer: a review. | Gastric cancer is common in China, and its early diagnosis and treatment are difficult. In recent years great progress has been achieved in gene therapy, and a wide array of gene therapy systems for gastric cancer has been investigated. The present article deals with the general principles of gene therapy and then focu... |
14605362 | Quantum coherence in an exchange-coupled dimer of single-molecule magnets. | A multi- high-frequency electron paramagnetic resonance method is used to probe the magnetic excitations of a dimer of single-molecule magnets. The measured spectra display well-resolved quantum transitions involving coherent superposition states of both molecules. The behavior may be understood in terms of an isotropi... |
14604392 | Highly selective oxidative cleavage of beta-cyclodextrin-epoxide/aziridine complexes with IBX in water. | Water, an environmentally friendly reaction medium, has been utilized for the reaction of IBX with various epoxides 1 and aziridines 2 as their beta-cyclodextrin complexes to afford for the first time alpha-hydroxyketones 3 and alpha-aminoketones 4, respectively. |
14604379 | Synthesis and hierarchical self-assembly of cavity-containing facial amphiphiles. | The synthesis and aggregation behavior of cavity-containing facial amphiphiles is described. The molecules consist of a glycoluril-based rigid cavity functionalized with two water-soluble benzoate groups. By specific molecular recognition processes in water, the amphiphilic hosts self-assemble in a hierarchical process... |
14604376 | Synthetic approaches to an isostructural series of redox-active, metal tris(bipyridine) core dendrimers. | Several types of six-armed, metal tris(bipyridine) core dendrimers were synthesized. Bis-4,4'-alkoxy bipyridine dendrons were prepared and employed to make tris(bipyridine) dendrimers. Although the ruthenium-centered and iron-centered dendrimers displayed quasi-reversible cyclic voltammetry, the analogous cobalt-center... |
14604363 | Synthesis, resolution, and applications of 1,16-dihydroxytetraphenylene as a novel building block in molecular recognition and assembly. | This paper concerns the synthesis of 1,16-dihydroxytetraphenylene (DHTP) (2) by employing a novel NBS bromination route. (+/-)-DHTP 2 was successfully resolved into its optical antipodes and converted to (+/-)-1,16-bis(diphenylphosphino)tetraphenylene (BPTP) (26), whose platinum complex BPTP-PtCl(2) (27) was also obtai... |
14604693 | Some new 2,3,6-trisubstituted quinazolinones as potent anti-inflammatory, analgesic and COX-II inhibitors. | Various 2-(substitutedphenylmethyleneimino)aminoacetylmethylene-3-(2'-substitutedindol-3'-yl)-halosubstituted-4(3H)quinazolinones (5a-5i) and 2-(substituted phenylaminomethyleneacetyl-4'-oxo-1'-thiazolidinyl-3-(2"-substitutedindol-3"-yl) 4(3H)-quinazolinones (6a-6i) have been synthesized in the present studies. The str... |
14604671 | Analysis of the non-covalent interaction between metal ions and the cysteine-rich domain of protein kinase C eta by electrospray ionization mass spectrometry. | Effect of zinc and other metal ions on the folding of the protein kinase C (PKC) surrogate peptide (PKCeta-C1B) was analyzed intact under neutral conditions by electrospray ionization mass spectrometry (ESI-MS). ESI-MS spectrum of 64ZnCl(2)-folded PKCeta-C1B clearly showed that PKCeta-C1B coordinates specifically two a... |
14602920 | Molecular determinants of the hpa regulatory system of Escherichia coli: the HpaR repressor. | The HpaR-mediated regulation of the hpa-meta operon (Pg promoter) of the 4-hydroxyphenylacetic acid catabolic pathway of Escherichia coli has been studied. The HpaR regulator was purified to homogeneity showing that it is able to bind selectively to 4-hydroxyphenylacetic, 3-hydroxyphenylacetic and 3,4-dihydroxyphenylac... |
14603324 | Crystal structure of a zinc-finger-RNA complex reveals two modes of molecular recognition. | Zinc-finger proteins of the classical Cys2His2 type are the most frequently used class of transcription factor and account for about 3% of genes in the human genome. The zinc-finger motif was discovered during biochemical studies on the transcription factor TFIIIA, which regulates the 5S ribosomal RNA genes of Xenopus ... |
14603503 | Enhancement of dehydroepiandrosterone solubility and bioavailability by ternary complexation with alpha-cyclodextrin and glycine. | In the present work we investigated the possibility of improving dehydroepiandrosterone (DHEA) solubility and bioavailability by high-energy cogrinding with alpha-cyclodextrin (alpha-Cd) in the presence or absence of different auxiliary substances (glycine, biomaltodextrin, poly(vinyl pyrrolidone), poly(ethylene glycol... |
14602833 | Two modes of vesicle recycling in the rat calyx of Held. | Vesicle recycling was studied in the rat calyx of Held, a giant brainstem terminal involved in sound localization. Stimulation of brain slices containing the calyx-type synapse with a high extracellular potassium ion concentration in the presence of horseradish peroxidase resulted within several minutes in a reduction ... |
14602389 | Extraction of o-phenylphenol from silicone tubing by a sulfobutylether cyclodextrin formulation. | During a compatibility study between a formulation containing sulfobutylether cyclodextrin (SBECD) and silicone tubing, an extraneous peak was observed in the HPLC chromatograms. The extraneous material was identified by LC/MS, MS/MS and UV as a previously unreported tubing extractable, o-phenylphenol (o-PP). Several s... |
14602387 | Enzymatic hydrolysis of diloxanide furoate in the presence of beta-cyclodextrin and its methylated derivatives. | In this study, we investigated the susceptibility to enzymatic and alkaline hydrolysis of diloxanide furoate (DF) and its cyclodextrin inclusion complexes, in aqueous solution. The cyclodextrins (CDs) utilized were beta-cyclodextrin (beta-CD), (2,6-di-O-methyl)-beta-cyclodextrin (DM-beta-CD) and (2,3,6-tri-O-methyl)-be... |
14602190 | Enhanced bioavailability of piroxicam using Gelucire 44/14 and labrasol: in vitro and in vivo evaluation. | Piroxicam is a non-steroidal anti-inflammatory drug that is characterized by low solubility and high permeability. The purpose of the study was to investigate the in vitro and in vivo performance of the semi-solid dispersion prepared with Gelucire 44/14 and Labrasol into hard gelatin capsules (GL) for enhancing the dis... |
14602173 | Comparison of the lung absorption of FK224 inhaled from a pressurized metered dose inhaler and a dry powder inhaler by healthy volunteers. | FK224 is a cyclopeptide drug with poor oral absorption due to proteolysis in the gastrointestinal tract. The objectives of this study were to investigate the absorption of FK224 from the lung in healthy volunteers, and compare the pharmacokinetic profiles of FK224 after inhalation from a pressurized metered dose inhale... |
14602172 | Cyclosporine A delivery to the eye: a pharmaceutical challenge. | Systemic administration of cyclosporine A (CsA) is commonly used in the treatment of local ophthalmic conditions involving cytokines, such as corneal graft rejection, autoimmune uveitis and dry eye syndrome. Local administration is expected to avoid the various side effects associated with systemic delivery. However, t... |
12954080 | Polyester synthases: natural catalysts for plastics. | Polyhydroxyalkanoates (PHAs) are biopolyesters composed of hydroxy fatty acids, which represent a complex class of storage polyesters. They are synthesized by a wide range of different Gram-positive and Gram-negative bacteria, as well as by some Archaea, and are deposited as insoluble cytoplasmic inclusions. Polyester ... |
14602657 | Influence of storage on monodispersed cells of Mycobacterium terrae used for quantitative carrier test prEN 14563. | The degree of cell clumping increased with time of storage (1% cell clumps immediately after homogenization and 3 and 6.5% after 48 and 96 h of storage, respectively), and the number of living single cells decreased. Quantitative carrier tests were carried out with these cells using ortho-phthaldialdehyde (OPA) and coc... |
14602648 | Peptide ligands that bind selectively to spores of Bacillus subtilis and closely related species. | As part of an effort to develop detectors for selected species of bacterial spores, we screened phage display peptide libraries for 7- and 12-mer peptides that bind tightly to spores of Bacillus subtilis. All of the peptides isolated contained the sequence Asn-His-Phe-Leu at the amino terminus and exhibited clear prefe... |
14602586 | Degradation of cross-linked and non-cross-linked arabinoxylans by the intestinal microbiota in children. | In humans, nonstarch polysaccharides (NSP), such as arabinoxylans (AX), are not digested in the upper gut and provide fermentable carbon sources for bacteria growing in the large bowel. Despite the ubiquity of AX in nature, the microbiologic and physiologic consequences of AX digestion in the gut are poorly understood.... |
14599221 | Crucial role of three-center hydrogen bonding in a challenging chiral molecular recognition. | The enantio-discrimination of beta-chiral primary ammonium ions is achieved by a rational approach that utilizes three-center (bifurcated) hydrogen bonding. The extraction experiments on various selected guests reveal that the bifurcated H-bonding plays a crucial role for the chiral discrimination. The X-ray data obtai... |
14599219 | Novel "Potentially antiaromatic", acidichromic quinonediimines with tunable delocalization of their 6 pi-electron subunits. | We present a novel family of "potentially antiaromatic" alkyl-substituted p-benzoquinonediimine pH-dependent chromophores. It appears from the structural data that these overall 12 pi-electron molecules should be better considered as constituted by two chemically connected but electronically not conjugated 6 pi-electro... |
14599204 | Supramolecular hydrogels respond to ligand-receptor interaction. | N-(Fluorenyl-9-Methoxycarbonyl) dipeptides form supramolecular hydrogels via hydrogen bonding and hydrophobic interactions. These hydrogels respond to a ligand-receptor interaction as well as to thermal or pH perturbation and also exhibit chiral recognition. |
14599187 | Calix[2]bipyrrole[2]furan and calix[2]bipyrrole[2]thiophene: new pyrrolic receptors exhibiting a preference for carboxylate anions. | Heterocycles other than pyrrole, specifically bipyrrole, furan, and thiophene, have been used to construct two new, calixpyrrole-like anion receptors; binding studies, carried out by ITC in CH3CN, reveal a selectivity for "Y-shaped" anions, such as benzoate, over spherical ones, such as chloride. |
14599594 | Irreversible self-assembly of ovalbumin into fibrils and the resulting network rheology. | The self-assembly of ovalbumin into fibrils and resulting network properties were investigated at pH 2, as a function of ionic strength. Using transmission electron microscopy (TEM), the effect of ovalbumin concentration on the contour length was determined. The contour length was increasing with increasing ovalbumin c... |
14600368 | Interactions of cholesterol with cyclodextrins in aqueous solution. | The interaction of cholesterol with several cyclodextrins (CDs) was investigated in water using solubility method. It was found that heptakis (2,6-di-O-methyl)-beta-CD (DOM-beta-CD) forms two types of soluble complex, with molar ratios of 1 : 1 and 1 : 2 (cholesterol : DOM-beta-CD), and neither a soluble nor insoluble ... |
14601164 | Synthetic expanded porphyrin chemistry. | Expanded porphyrins are synthetic analogues of the porphyrins, and differ from these and other naturally occurring tetrapyrrolic macrocycles by containing a larger central core with a minimum of 17 atoms, while retaining the extended conjugation features that are a hallmark of these quintessential biological pigments. ... |
14594617 | Oxidative stress-related mechanisms are associated with xenobiotics exerting excess toxicity to Fanconi anemia cells. | An extensive body of evidence has demonstrated the sensitivity of Fanconi anemia (FA) cells to redox-active xenobiotics, such as mitomycin C, diepoxybutane, cisplatin, and 8-methoxypsoralen plus ultraviolet irradiation, with toxicity mechanisms that are consistent with a deficiency of FA cells in coping with oxidative ... |
14598323 | EP24.15 is associated with lipid rafts. | Metalloendopeptidase EC 3.4.24.15 (EP24.15, thimet oligopeptidase) is a neuropeptide-metabolizing peptidase expressed throughout the body, but primarily in the brain, gonads, and pituitary. For EP24.15 to have its greatest effect upon peptides in the periphery, it must be targeted and released into the extracellular sp... |
14597118 | Determination of the activation energy for unimolecular dissociation of a non-covalent gas-phase peptide: substrate complex by infrared multiphoton dissociation fourier transform ion cyclotron resonance mass spectrometry. | The activation energy for the unimolecular dissociation of a non-covalent supramolecular complex between an Artificial Cationic Receptor A ([Gua-Val-Val-Val-Amide]+, in which Gua is guanidiniocarbonyl pyrrole) and an Anionic Tetrapeptide B ([N-Acetyl-Val-Val-Ile-Ala]-) has been determined by measurement of the dissocia... |
14597663 | An mRNA structure in bacteria that controls gene expression by binding lysine. | Riboswitches are metabolite-responsive genetic control elements that reside in the untranslated regions (UTRs) of certain messenger RNAs. Herein, we report that the 5'-UTR of the lysC gene of Bacillus subtilis carries a conserved RNA element that serves as a lysine-responsive riboswitch. The ligand-binding domain of th... |
14596618 | Fucoxanthin-chlorophyll proteins in diatoms: 18 and 19 kDa subunits assemble into different oligomeric states. | Fucoxanthin-chlorophyll proteins were purified from the centric diatom Cyclotella meneghiniana. Two major fractions were observed that differed in their polypeptide composition and oligomeric state. Trimers consist of mainly 18 kDa polypeptides. Higher oligomers are tightly assembled from different trimers, which conta... |
14596588 | Highly effective poly(ethylene glycol) architectures for specific inhibition of immune receptor activation. | Architectural features of synthetic ligands were systematically varied to optimize inhibition of mast cell degranulation initiated by multivalent crossing of IgE-receptor complexes. A series of ligands were generated by end-capping poly(ethylene glycol) (PEG) polymers and amine-based dendrimers with the hapten 2,4-dini... |
14594821 | Negative osmoregulation of the Salmonella ompS1 porin gene independently of OmpR in an hns background. | The ompS1 gene encodes a quiescent porin in Salmonella enterica serovars Typhi and Typhimurium. By using random mariner transposon mutagenesis, mutations that caused derepression of ompS1 expression were isolated, one in S. enterica serovar Typhi and two in S. enterica serovar Typhimurium. All of them mapped in the hns... |
14592694 | The effect of pH and triethanolamine on sulfisoxazole complexation with hydroxypropyl-beta-cyclodextrin. | A novel complexation of sulfisoxazole with hydroxypropyl-beta-cyclodextrin (HP-beta-CD) was studied. Two systems were used: binary complexes prepared with HP-beta-CD and multicomponent system (HP-beta-CD and the basic compound triethanolamine (TEA)). Inclusion complex formation in aqueous solutions and in solid state w... |
14592691 | Physicochemical investigation of the effects of water-soluble polymers on vinpocetine complexation with beta-cyclodextrin and its sulfobutyl ether derivative in solution and solid state. | The studies reported in this work aimed to elucidate the inclusion complex formation of vinpocetine (VP), a poorly water-soluble base type drug, with beta-cyclodextrin (betaCD) and its sulfobutyl ether derivative (sulfobutyl ether beta-cyclodextrin (SBEbetaCD)), with or without water-soluble polymers (PVP and HPMC), by... |
14593443 | RNA sensors: novel regulators of gene expression. | RNA-mediated control can evolve far more rapidly than mechanisms that rely on proteins, creating selective advantages in adaptive gene regulation. Recently, evidence has emerged that messenger RNA is a source of cis-acting RNA elements that sense external signals and thereby regulate gene expression. With exquisite spe... |
14592515 | Interaction of the disodium disuccinate derivative of meso-astaxanthin with human serum albumin: from chiral complexation to self-assembly. | To exploit the promising biochemical activities of naturally-occurring and synthetic hydrophobic carotenoids, it is necessary to improve their aqueous solubility. The disodium disuccinate derivative of synthetic meso-astaxanthin was prepared, and its behavior in pH 7.4 buffer solutions in both the presence and absence ... |
14588006 | Beta-cyclodextrin-based ferrocene-imprinted gold electrodes. | A new stepwise self-assembly procedure is described for the preparation of functional cyclodextrin-modified electrodes. The approach is based on the formation of alkanethiol/lipoylamide-beta-cyclodextrin monolayers with the thiol component responsible for blocking of the electrode surface and lipoylamide-beta-cyclodext... |
14588003 | Enzyme-amplified electrochemical detection of DNA using electrocatalysis of ferrocenyl-tethered dendrimer. | We have developed a sandwich-type enzyme-linked DNA sensor as a new electrochemical method to detect DNA hybridization. A partially ferrocenyl-tethered poly(amidoamine) dendrimer (Fc-D) was used as an electrocatalyst to enhance the electronic signals of DNA detection as well as a building block to immobilize capture pr... |
14584948 | 2-Substitution of adenine nucleotide analogues containing a bicyclo[3.1.0]hexane ring system locked in a northern conformation: enhanced potency as P2Y1 receptor antagonists. | Preference for the northern (N) ring conformation of the ribose moiety of adenine nucleotide 3',5'-bisphosphate antagonists of P2Y(1) receptors was established by using a ring-constrained methanocarba (a bicyclo[3.1.0]hexane) ring as a ribose substitute (Nandanan et al. J. Med. Chem. 2000, 43, 829-842). We have now com... |
14584937 | Synthesis and Ca2+-mobilizing activity of purine-modified mimics of adenophostin A: a model for the adenophostin-Ins(1,4,5)P3 receptor interaction. | The synthesis of a series of adenophostin A analogues modified at C-6 and C-2 of adenine is described. The target compounds were synthesized by a convergent route involving a modified Vorbrüggen condensation of either 6-chloropurine or 2,6-dichloropurine with a protected disaccharide, yielding two versatile intermediat... |
14584936 | Modeling the adenosine receptors: comparison of the binding domains of A2A agonists and antagonists. | A three-dimensional model of the human A(2A) adenosine receptor (AR) and its docked ligands was built by homology to rhodopsin and validated with site-directed mutagenesis and the synthesis of chemically complementary agonists. Different binding modes of A(2A)AR antagonists and agonists were compared by using the Flexi... |
14587034 | Hepatic stellate cells uptake of retinol associated with retinol-binding protein or with bovine serum albumin. | Retinol is stored in liver, and the dynamic balance between its accumulation and mobilization is regulated by hepatic stellate cells (HSC). Representing less than 1% total liver protein, HSC can reach a very high intracellular retinoid (vitamin-A and its metabolites) concentration, which elicits their conversion from t... |
14583283 | Synthesis and infrared and fluorescence spectral properties of luminescent terbium and europium complexes with open-chain carboxylate crown ethers. | Two open-chain carboxylate crown ether ligands and their terbium(III) and europium(III) complexes were synthesized and characterized. The terbium and europium ions were found to coordinate to the carboxylate oxygens. The fluorescence properties of europium complexes in the solid state and terbium complexes in the solid... |
14583269 | Study on the interaction of methylene blue with cyclodextrin derivatives by absorption and fluorescence spectroscopy. | The ability of beta-cyclodextrin (beta-CD), hydroxypropyl-beta-cyclodextrin (HP-beta-CD), and carboxymethyl-beta-cyclodextrin (CM-beta-CD) to break the aggregate of the methylene blue (MB) and to form 1:1 inclusion complexes has been studied by absorption and fluorescence spectroscopy. Experimental conditions including... |
14583268 | Studies of solvation in homogeneous and heterogeneous media by electronic spectroscopic method. | Solvation characteristics in homogenous (pure and mixed binary solvents) and heterogeneous media (aqueous micelles, beta- and gamma-cyclodextrine solutions) have been studied by monitoring the emission characteristics of a newly synthesised dye. The longest wavelength absorption and emission band of the dye arise due t... |
14583189 | Phase diagram of nucleosome core particles. | We present a phase diagram of the nucleosome core particle (NCP) as a function of the monovalent salt concentration and applied osmotic pressure. Above a critical pressure, NCPs stack on top of each other to form columns that further organize into multiple columnar phases. An isotropic (and in some cases a nematic) pha... |
14583059 | Intramolecular directional förster resonance energy transfer at the single-molecule level in a dendritic system. | We report on the directional Förster resonance energy transfer (FRET) process taking place in single molecules of a first (T1P4) and a second (T2P8) generation of a perylenemonoimide (P)-terrylenediimide (T)-based dendrimer in which the chromophores are separated by rigid polyphenylene arms. At low excitation powers, s... |
14583047 | Molecular imprinting inside dendrimers. | Synthetic hosts capable of binding porphyrins have been produced by a mixed-covalent-noncovalent imprinting process wherein a single binding site is created within cross-linked dendrimers. Two synthetic hosts were prepared, using as templates 5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin and 5,10,15,20-tetrakis(3,5-dih... |
14583042 | Comparison of excited-state energy transfer in arrays of hydroporphyrins (chlorins, oxochlorins) versus porphyrins: rates, mechanisms, and design criteria. | A set of chlorin-chlorin and oxochlorin-oxochlorin dyads has been prepared with components in the same or different metalation states. In each case a 4,4'-diphenylethyne linker spans the respective 10-position of each macrocycle. The dyads have been studied using static and time-resolved absorption and emission spectro... |
14583023 | Chiroptical switching in a bistable molecular shuttle. | Although various methods for switching the positions of macrocycles in bistable rotaxane-based molecular shuttles have been developed, exploiting such movements to trigger property changes has thus far received little attention. Here we describe one of the first examples of a property change achieved through a controll... |
14583009 | Dicopper-[18]ane-N6 complex as the platform for phosphate monoester binding. | Dicopper-[18]ane-N6 complex functions as a broad spectrum receptor for phosphate monoesters. |
14581566 | Presence of host ICAM-1 in human immunodeficiency virus type 1 virions increases productive infection of CD4+ T lymphocytes by favoring cytosolic delivery of viral material. | Although there is now convincing evidence that the infectivity of human immunodeficiency virus type 1 (HIV-1) is increased by incorporation of host intercellular adhesion molecule 1 (ICAM-1) in budding virions, the exact mechanism(s) through which ICAM-1 can so significantly affect HIV-1 biology remains obscure. To add... |
14581554 | Colocalization and interaction of the porcine arterivirus nucleocapsid protein with the small nucleolar RNA-associated protein fibrillarin. | Porcine reproductive and respiratory syndrome virus (PRRSV) replicates in the cytoplasm of infected cells, but its nucleocapsid (N) protein localizes specifically to the nucleus and nucleolus. The mechanism of nuclear translocation and whether N associates with particular nucleolar components are unknown. In the presen... |
14581551 | Human immunodeficiency virus type 1 enters primary human brain microvascular endothelial cells by a mechanism involving cell surface proteoglycans independent of lipid rafts. | Several studies have reported a crucial role for cholesterol-enriched membrane lipid rafts and cell-associated heparan sulfate proteoglycans (HSPGs), a class of molecules that can localize in lipid rafts, in the entry of human immunodeficiency virus type 1 (HIV-1) into permissive cells. For the present study, we examin... |
14581550 | Intracellularly expressed single-domain antibody against p15 matrix protein prevents the production of porcine retroviruses. | The presence of porcine endogenous retroviruses presents a potential risk of transmission of infectious diseases (xenozoonosis) if tissues and organs from genetically modified pigs are to be used in xenotransplantation. Here, we report that intracellular expression of a llama single-domain antibody against p15, the mat... |
14581535 | Receptor priming of major group human rhinoviruses for uncoating and entry at mild low-pH environments. | Receptor priming of low-pH-triggered virus entry has been described for an enveloped virus (15). Here we show with major group human rhinoviruses (HRV) and its intercellular adhesion molecule-1 receptor that nonenveloped viruses follow this novel cell entry principle. In vitro the receptor primed HRV for efficient unco... |
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