id stringlengths 4 8 | title stringlengths 1 642 | abstract stringlengths 50 17.9k |
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12588543 | Stimulation of ligninolytic enzyme production in Phanerochaete chrysosporium by polyoxyalkanes. | <h4>Aims</h4>Poly(ethylene glycol) (PEG) and some substances similar to PEG in chemical structure were tested as stimulators of ligninolytic enzyme production in shaken culture of Phanerochaete chrysosporium.<h4>Methods and results</h4>The substances that caused high enzymatic activity were linear polymers [poly(ethyle... |
12589256 | [In vitro uranyle affinity of per (3,6-anhydro-2-O-carboxyméthyle)-alpha-cyclodextrin and conditions required for in vivo application]. | Per (3.6-anhydro-2-O-carboxymethyle)- alpha-cyclodextrin ([1]) is a polydentate analog of EDTA, a well-known cation chelating reagent. [1] exhibits strong affinities in vitro for lanthanids, cobalt and also for uranyl cations. Hence, a 1:1 stoechiometry and a high affinity for uranyle (6<logK<7) is found in vitro. More... |
12586706 | Sequence variation of alcohol dehydrogenase (Adh) paralogs in cactophilic Drosophila. | This study focuses on the population genetics of alcohol dehydrogenase (Adh) in cactophilic Drosophila. Drosophila mojavensis and D. arizonae utilize cactus hosts, and each host contains a characteristic mixture of alcohol compounds. In these Drosophila species there are two functional Adh loci, an adult form (Adh-2) a... |
14595830 | Organic supramolecular architectures and their sol-gel transcription to Silica nanotubes. | The design of artificial models of "biomineralization" processes that utilize sol-gel polymerization has led to a merging of inorganic materials research and supramolecular organic chemistry. This article introduces self-assembled superstructures of sugar-integrated and crown-appended cholesterol gelators, which are us... |
12585431 | Synthesis of tripodal [2]rotaxanes: high concentration principlet. | Symmetrical and non-symmetrical tripodal [2]rotaxanes (1) incorporating 1,1'-disubstituted-4,4'-bipyridinium cations (2) and 34-crown-10 (3) have been prepared directly from 4,4'-bipyridine or from monocationic intermediates in high yields at room temperature and atmospheric pressure under conditions that permit the us... |
12585430 | A divergent approach to the precise synthesis of giant organometallic dendrimers using platinum-acetylides as building blocks. | Giant platinum-acetylides dendrimers were precisely synthesized by a divergent method; the sixth generation dendrimer, the diameter of which is larger than 10 nm, has 189 Pt atoms per molecule, and its molecular weight is as high as 139750. |
12585421 | In situ cyclodextrin-based homogeneous incorporation of metal (M = Pd, Pt, Ru) nanoparticles into silica with bimodal pore structure. | In situ cyclodextrin (CD)-based homogeneous incorporation of metal (M = Pd, Pt, Ru) nanoparticles into silica with bimodal pore structure has been realized by utilizing the self-assembly aggregation and inclusion capability of the CDs. |
12585383 | Crystal engineering of the composition of pharmaceutical phases. | The carboxylic acid-pyridine supramolecular heterosynthon can be exploited to predictably generate binary crystalline phases involving rac-ibuprofen, rac-flurbiprofen or aspirin. |
12580546 | Phosphorylated protein kinases associated with neuronal and glial tau deposits in argyrophilic grain disease. | Tau phosphorylation was examined in argyrophilic grain disease (AGD) by using the phosphospecific tau antibodies Thr181, Ser202, Ser214, Ser 396 and Ser422, and antibodies to non-phosphorylated and phosphorylated mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinases (ERK), stress-activated kin... |
14587086 | Comparing differentiation of xylene isomers by electronic ionization, chemical ionization and self-ion/molecule reactions and the first observation of methyne addition ions for xylene isomers in self-ion/molecule reactions for non-nitrogenated compounds. | This study presents the self-ion/molecule reaction (SIMR) spectra of three xylene isomers, and proposes an approach to differentiating them based on observed differences in relative abundances of ions formed by SIMR in an internal source ion trap instrument. It also demonstrates the applicability of SIMR for isomer dis... |
12580518 | Separation of opiate alkaloids by electrokinetic chromatography with sulfated-cyclodextrin as a pseudo-stationary phase. | The separation of six related opiate alkaloids (morphine, thebaine, 10-hydroxythebaine, codeine, oripavine and laudanine) was studied using sulfated-cyclodextrin (s-CD) as a cation-exchange pseudo-stationary phase. Cation-exchange interactions between the cationic analytes and the anionic s-CD (7-11 mol of sulfate grou... |
12580516 | Separation of conjugated trienoic fatty acid isomers by capillary electrophoresis. | A method for direct resolution of conjugated trienoic fatty acid isomers by capillary electrophoresis has been developed. To obtain complete separation a dual cyclodextrin system was used. This contained heptakis-(6-sulfo)-beta-cyclodextrin (charged). Beta-cyclodextrin (uncharged) and sodium dodecylsulfate. Under optim... |
12580515 | Determination of free L- and D-alanine in hydrolysed protein fertilisers by capillary electrophoresis. | of racemisation of hydrolysed protein fertilisers (HPFs) using an The objective of this study was to determine the degree inexpensive and easy to handle analytical method for qualitative control of the products. Using a polyacrylamide coated capillary and a run buffer containing 0.1 M Tris-borate+2.5 mM EDTA-Na2+0.1% s... |
12580500 | Chiral separation of gamma-butyrolactone derivatives by gas chromatography on 2,3-di-O-methyl-6-O-tert.-butyldimethylsilyl-beta-cyclodextrin. | The chiral GC separation of 2-alkyl-2-keto-gamma-butyrolactone derivatives and their alcohol analogs using 2,3-di-O-methyl-6-O-tert.-butyldimethylsilyl-beta-cyclodextrin (DIMETBCD) as chiral selector was discussed. The results, supported by the ketone preliminary molecular modelling calculations, suggest that the chira... |
12576275 | Copper(II) complexes with uridine, uridine 5'-monophosphate, spermidine, or spermine in aqueous solution. | Molecular complexes of the types (Urd)H(x)(PA) and (UMP)H(x)(PA) are formed in the uridine (Urd) or uridine 5'-monophosphate (UMP) plus spermidine or spermine systems, as shown by the results of equilibrium and spectral studies. Overall stability constants of the adducts and equilibrium constants of their formation hav... |
14583116 | The Karyote physico-chemical genomic, proteomic, metabolic cell modeling system. | Modeling approaches to the dynamics of a living cell are presented that are strongly based on its underlying physical and chemical processes and its hierarchical spatio-temporal organization. Through the inclusion of a broad spectrum of processes and a rigorous analysis of the multiple scale nature of cellular dynamics... |
12573008 | Efficient lipid delivery to hybridoma culture by use of cyclodextrin in a novel granulated dry-form medium technology. | Lipids are critical nutrients for high density eukaryotic cell cultivation, but inclusion of lipid components into dry-form media has been technically challenging. Lipid supplements are usually supplied for separate addition after powder reconstitution and filtration, which increases manipulation and risk in a biopharm... |
12572805 | Membrane introduction mass spectrometry for monitoring complexation equilibria of beta-cyclodextrin with substituted benzenes. | Membrane introduction mass spectrometry (MIMS) was used to monitor complexation reactions between beta-cyclodextrin (CD) and a series of benzene derivatives in aqueous solution. The equilibrium constants for benzene, chlorobenzene, bromobenzene, iodobenzene, toluene, cyanobenzene and nitrobenzene were determined. The s... |
12568919 | Synthesis of starch derivatives with labile cationic groups. | A new route to starch derivatives bearing hydrolyzable cationic groups was developed. This was based on reacting starch compounds with betaine derivatives in the presence of diisopropylcarbodiimide and 4-dimethylaminopyridine as coupling reagents in an aprotic polar solvent. Water-soluble starches with a perfectly cont... |
12569528 | Synergistic effects of ion-pairing in the enantiomeric separation of basic compounds with cyclodextrin derivatives in nonaqueous capillary electrophoresis. | The enantiomeric separation of various kinds of basic pharmaceuticals has been investigated in nonaqueous capillary electrophoresis (NACE) systems using an ion-pairing reagent in combination with cyclodextrins (CDs). The simultaneous addition to the methanolic background electrolyte (BGE) of (+)-S-camphorsulfonate or a... |
12569527 | Synthesis, analytical characterization and use of octakis(2,3-di-O-methyl-6-O-sulfo)-gamma-cyclodextrin, a novel, single-isomer, chiral resolving agent in low-pH background electrolytes. | The third member of the family of single-isomer, sulfated gamma-cyclodextrins, the sodium salt of octakis(2,3-di-O-methyl-6-O-sulfo)-gamma-cyclodextrin has been synthesized, analytically characterized and used for the capillary electrophoretic separation of the enantiomers of nonionic, weak acid and weak base analytes ... |
12569526 | Enhancement of selectivity and resolution in the enantioseparation of uncharged compounds using mixtures of oppositely charged cyclodextrins in capillary electrophoresis. | The enantiomeric separation of some nonsteroidal anti-inflammatory drugs (NSAIDs) was investigated in capillary electrophoresis (CE) using dual systems with mixtures of charged cyclodextrin (CD) derivatives. A significant enhancement of selectivity and resolution could be achieved in the enantioseparation of these anal... |
12569523 | Background and operating parameters in microemulsion electrokinetic chromatography. | Microemulsion electrokinetic chromatography (MEEKC) is an electrodriven separation technique. Separations are generally achieved using microemulsions consisting of surfactant-coated nanometer-sized oil droplets suspended in aqueous buffer. A cosurfactant such as a short-chain alcohol is generally used to stabilize the ... |
12568373 | Enantioselective ion-exclusion chromatography on teicoplanin aglycone and (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid stationary phases. | Ion-exclusion chromatography is a well established technique for the analysis of achiral ionic species, but it has rarely been applied to chiral analytes. In this paper enantioselective ion-exclusion separations were developed on two commercially available HPLC phases: Chirobiotic TAG, based on teicoplanin aglycone, an... |
15260240 | The bacterial scaffoldin: structure, function and potential applications in the nanosciences. | Natural protein complexes may provide the best templates for nanometer-scale technology and new biomaterials. The bacterial cellulosome is becoming a well-understood multi-protein complex found in cellulolytic microorganisms. The scaffoldin subunits of the bacterial cellulosome function to organize and position other p... |
12564687 | Preparation and application of a new modified liquid chromatographic chiral stationary phase based on (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid. | As an effort to improve the chiral recognition efficiency of a previously reported chiral stationary phase (CSP) based on (+)-(18-Crown-6)-2,3,11,12-tetracarboxylic acid, a new CSP was prepared by simply replacing the amide N-H hydrogens of the tethering groups of the old CSP with methyl groups. The new CSP was superio... |
12564682 | Exploration of the electrophoretic behaviour of borane cluster anions and of the capability of capillary electrophoresis to separate them chirally. | Mobilities of investigated boron cluster compounds in 3-(N-morpholino)propanesulfonic and phosphate buffers adjusted to pH 7 either with sodium hydroxide or with tris(hydroxymethyl)aminomethane depend on both buffer ions. The zone width and zone asymmetry, which are usually markedly higher than those of organic or comm... |
12564681 | Use of dynamically coated capillaries with added cyclodextrins for the analysis of opium using capillary electrophoresis. | A rapid, precise, accurate, and robust method using capillary electrophoresis (CE) with dynamically coated capillaries for the analysis of the major opium alkaloids in opium is presented. Dynamic coating of the capillary surface is accomplished using a commercially available reagent kit (polycation coating followed by ... |
12558049 | Evaluation of the molecular recognition of peptide-conjugated polymer. | We have recently reported on dodecamer peptides (HPPMDFHKAMTR, CHPQPLKSRNPL) which recognize 52-58th and 197-203rd amino acid sequences of glucose oxidase (GOx) by screening via a phage random peptide library. In this study, a side-chain protected peptide monomer (PPM) was synthesized using two peptides (HPPMDFHKAMTR, ... |
12558035 | Lasting chemiluminescence of 3-indoleglyoxylyl chloride and its enhancement. | The chemiluminescence (CL) intensities of various indole derivatives substituted with a glyoxylyl group at the 3-position and a hydroxyl group at the 5-position of the indole ring were compared upon the addition of H2O2 in alkaline media. The CL intensities of 3-indoleglyoxylyl chloride, 3-indoleglyoxylic acid, 5-hydro... |
12557239 | Interaction of epitope-related and -unrelated peptides with anti-p24 (HIV-1) monoclonal antibody CB4-1 and its Fab fragment. | The binding of four epitope-related peptides and three library-derived, epitope-unrelated peptides of different lengths (10-14 amino acids) and sequence by anti-p24 (HIV-1) monoclonal antibody CB4-1 and its Fab fragment was studied by isothermal titration calorimetry. The binding constants K(A) at 25 degrees C vary bet... |
12557238 | Kinetic analysis of the interactions between troponin C (TnC) and troponin I (TnI) binding peptides: evidence for separate binding sites for the 'structural' N-terminus and the 'regulatory' C-terminus of TnI on TnC. | The Ca(2+)/Mg(2+)-dependent interactions between TnC and TnI play a critical role in regulating the 'on' and 'off' states of muscle contraction as well as maintaining the structural integrity of the troponin complex in the off state. In the present study, we have investigated the binding interactions between the N-term... |
12557237 | Human CD30: structural implications from epitope mapping and modeling studies. | The human CD30 molecule is expressed transiently at very low levels on intrafollicular and perifollicular T and B cell blasts in lymphoid tissues, but is specifically upregulated on certain tumor cells, e.g. Hodgkin and Reed-Sternberg (H-RS) cells. With its specific expression pattern and easy accessibility on the surf... |
12557236 | RNA aptamers specific for bovine thrombin. | Bovine thrombin is widely used in clinical wound healing after surgery. There is 85% homology between bovine thrombin and human thrombin, so most antibodies against bovine thrombin cross-react with human thrombin. Rare antibodies against bovine thrombin but not cross-reacting with human thrombin have been reported. RNA... |
12557235 | BEPITOPE: predicting the location of continuous epitopes and patterns in proteins. | In growing need of obtaining highly specific monoclonal antibodies against novel proteins, we developed new functions implemented in the program BEPITOPE to predict continuous protein epitopes. This program not only can compute, combine, display and print prediction profiles, but also provides a list of suggested linea... |
12557234 | Design and use of multi-affinity surfaces in biomolecular interaction analysis-mass spectrometry (BIA/MS): a step toward the design of SPR/MS arrays. | The feasibility of multi-affinity ligand surfaces in biomolecular interaction analysis-mass spectrometry (BIA/MS) was explored in this work. Multi-protein affinity surfaces were constructed by utilizing antibodies to beta-2-microglobulin, cystatin C, retinol binding protein, transthyretin, serum amyloid P and C-reactiv... |
12557233 | Delineating protein-protein interactions via biomolecular interaction analysis-mass spectrometry. | The utility of biomolecular interaction analysis-mass spectrometry (BIA/MS) in screening for protein-protein interactions was explored in this work. Experiments were performed in which proteins served as ligands for screening of possible interactions with other proteins from human plasma and urine. The proteins utilize... |
12557232 | The use of the resonant mirror biosensor to detect point mutations, as demonstrated with synthetic oligonucleotides. | The possibility of using the resonant mirror biosensor to detect point substitutions in oligonucleotides was demonstrated with a fragment of the Helicobacter pylori 23S rRNA gene, point mutations in which are responsible for clarythromycin resistance. Conditions were optimized for the interaction of a probe immobilized... |
14569774 | [Types of coaptation of nerve fiber bundles and effectiveness of the nerve suture]. | Experiments in 26 dogs were carried out in order to analyze the quality of comparing the nerve fiber bundles, morphometrical and functional parameters of regeneration after the restoration of the nerve with a standard epineural microsurgical suture and by an original method including the coaptation of the freshened end... |
12554874 | Identification of the Hfq-binding site on DsrA RNA: Hfq binds without altering DsrA secondary structure. | DsrA RNA regulates the translation of two global regulatory proteins in Escherichia coli. DsrA activates the translation of RpoS while repressing the translation of H-NS. The RNA-binding protein Hfq is necessary for DsrA to function in vivo. Although Hfq binds to DsrA in vitro, the role of Hfq in DsrA-mediated regulati... |
12551711 | AFM imaging of calixarene based solid lipid nanoparticles in gel matrices. | Contact mode atomic force microscopy has been carried out on gels of four current polymers, carbopol 980, carbopol 2020, hyaluronic acid and xanthan containing dispersions of solid lipid nanoparticles (SLNs) of amphiphilic calixarenes. Imaging shows that the SLNs are dispersed within the gels as discrete particles of 1... |
12551708 | Influence of beta-cyclodextrin complexation on carbamazepine release from hydroxypropyl methylcellulose matrix tablets. | The in vitro release profiles of carbamazepine and beta-cyclodextrin either complexed or simply mixed and subsequently incorporated in hydrophilic matrix tablets containing 15 or 30% hydroxypropyl methylcellulose were evaluated. Solubility studies revealed a linear relationship between the increase in carbamazepine sol... |
12549563 | Molecular-level investigation of monoaromatic compound sorption to suspended soil particles by deuterium nuclear magnetic resonance. | Molecular-level sorption behavior of monoaromatic compounds in suspensions of water-dispersable clay components was studied by measuring 2H nuclear magnetic resonance (NMR) spin-spin relaxation times (T2). In general, decreased T2 values indicate stronger solute-sorbent interactions and increased sorption of the solute... |
12547491 | UV-B induced keratinocyte apoptosis is blocked by 2-selenium-bridged beta-cyclodextrin, a GPX mimic. | Cell proliferation and cell death of keratinocytes are tightly regulated to ensure epidermal homeostasis. UV-B induces keratinocyte apoptosis. UV-B also induces lipid peroxidation of keratinocytes to increase their amount of malondialdehyde (MDA). These phenomena can be explained by the production of reactive oxygen sp... |
12543813 | Anti-CD20 therapeutic antibody rituximab modifies the functional organization of rafts/microdomains of B lymphoma cells. | Incubation of Burkitt lymphoma-derived Raji cells at physiological temperature with submicromolar concentrations of humanized anti-CD20 antibody rituximab (RTX) redistributes CD20 to liquid-ordered, plasma membrane rafts. This accumulation of the CD20 tetraspan protein in rafts does not change the existing lipid and ph... |
12543772 | Micro-magnetic resonance lymphangiography in mice using a novel dendrimer-based magnetic resonance imaging contrast agent. | Major advances in cancer biology and immunology have been gained using mouse models. However, very few methods are currently available to visualize the deep lymphatic system. A new micro-magnetic resonance lymphangiography (MRL) method in mice, which uses dendrimer-based magnetic resonance imaging contrast agents, was ... |
12540955 | Localization of tissue factor pathway inhibitor to lipid rafts is not required for inhibition of factor VIIa/tissue factor activity. | Tissue factor pathway inhibitor (TFPI) abrogates coagulation initiated by the factor VIIa/tissue factor catalytic complex. While the gene structure of TFPI suggests that it is a secreted protein, a large pool of TFPI is associated with the vascular endothelium through its affinity for a glycosylphosphati-dylinositol (G... |
12540916 | DNA in a material world. | The specific bonding of DNA base pairs provides the chemical foundation for genetics. This powerful molecular recognition system can be used in nanotechnology to direct the assembly of highly structured materials with specific nanoscale features, as well as in DNA computation to process complex information. The exploit... |
12540529 | Alprostadil suppresses angiogenesis in vitro and in vivo in the murine Matrigel plug assay. | 1. Prostaglandin E(1) (PGE(1), alprostadil) is used as a vasodilator for the treatment of peripheral vascular diseases. 2. Previous reports suggested a pro-angiogenic effect for PGE(1). 3. We studied the in vitro and in vivo effect of PGE(1), complexed with alpha-cyclodextrin, on the angiogenic process. Contrary to wha... |
12540522 | Characterization of opioid receptors that modulate nociceptive neurotransmission in the trigeminocervical complex. | 1. Opioid agonists have been used for many years to treat all forms of headache, including migraine. We sought to characterize opioid receptors involved in craniovascular nociceptive pathways by in vivo microiontophoresis of micro -receptor agonists and antagonists onto neurons in the trigeminocervical complex of the c... |
12537499 | Molecular tectonics. Use of the hydrogen bonding of boronic acids to direct supramolecular construction. | Tetraboronic acids 1 and 2 have four -B(OH)(2) groups oriented tetrahedrally by cores derived from tetraphenylmethane and tetraphenylsilane. Crystallization produces isostructural diamondoid networks held together by hydrogen bonding of the -B(OH)(2) groups, in accord with the tendency of simple arylboronic acids to fo... |
12537495 | Supramolecular catalysis of the enantiodifferentiating [4 + 4] photocyclodimerization of 2-anthracenecarboxylate by gamma-cyclodextrin. | 2-Anthracenecarboxylic acid (AC) makes a very stable 1:2 inclusion complex with gamma-cyclodextrin (gamma-CDx) (K(1) = 161 +/- 25 M(-1), K(2) = 38 500 +/- 3300 M(-1) at 25 degrees C). The formation of the 1:2 inclusion complex accelerated the photocyclodimerization of AC. The 1:2 inclusion could be clearly verified by ... |
12537489 | Combined use of NMR relaxation measurements and hydrodynamic calculations to study protein association. Evidence for tetramers of low molecular weight protein tyrosine phosphatase in solution. | We describe a novel method for determining weak association constants of oligomeric protein complexes formed transiently under equilibrium conditions. This type of equilibrium process is recognized as being biologically important, but generally hard to study. Heteronuclear spin relaxation rates measured at multiple pro... |
12534303 | Supramolecular systems as microreactors: control of product selectivity in organic phototransformation. | This Account reviews the developments in microreactor-controlled selectivity in organic phototransformation. Photocycloaddition of alpha,omega-diaryl compounds with long flexible chains within Y-type zeolite and low-density polyethylene films leads to formation of intramolecular cyclomers to the exclusion of intermolec... |
12533599 | A role for the juxtamembrane domain of beta-dystroglycan in agrin-induced acetylcholine receptor clustering. | Synaptic differentiation results from an exchange of informational molecules between synaptic partners during development. At the vertebrate neuromuscular junction, agrin is one molecule presented by the presynaptic motor neuron that plays an instructive role in postsynaptic differentiation of the muscle cell, most not... |
12530895 | An expedient approach to internally functionalized chiral dendrimers: synthesis of a dendritic molecule incorporating furanoside skeleton. | In an approach to chiral dendritic molecules, a dendrimer incorporating pentose units in the interior and hexose units in the periphery is built up on a 1, 3, 5-trisubstituted aromatic core by using 1,2:5,6-diisopropylidene glucose as the carbohydrate precursor and a 3, 5-disubstituted aromatic unit as the branching bl... |
12530890 | Molecular taekwondo. 2. A new calix[4]azacrown bearing two different binding sites as a new fluorescent ionophore. | Synthesis and binding studies of a new calixarene-based fluoroionophore were made. Calix[4]azacrown having an anthracenyl unit displayed large chelation-enhanced fluorescence effects with Cs(+), Rb(+), and K(+) over other metal ion tested. Interesting "molecular taekwondo" processes between Cs(+)-Cu(2+) and Cs(+)-Ag(+)... |
12530880 | Synthesis of novel bis(beta-cyclodextrin)s and metallobridged bis(beta-cyclodextrin)s with 2,2'-diselenobis(benzoyl) tethers and their molecular multiple recognition with model substrates. | To investigate quantitatively the cooperative binding ability of beta-cyclodextrin dimers, a series of bridged bis(beta-cyclodextrin)s with 2,2'-diselenobis(benzoyl) spacer connected by different lengths of oligo(ethylenediamine)s (2-5) and their platinum(IV) complexes (6-9) have been synthesized and their inclusion co... |
12530856 | Solid-state diphotocyclization of iso- and terephthalaldehydes via dihalogen substitution. | The supramolecular nonbonded C-H...X interactions between formyl hydrogens and ortho-halogen atoms (Br/Cl) have been exploited to achieve conformational control in the solid state of dimethyl-substituted iso- and terephthaladehydes (1-3) for unprecedented diphotocyclization. It is shown that the dihalogen substitution ... |
12530846 | Efficient synthesis of porphyrin-containing, benzoquinone-terminated, rigid polyphenylene dendrimers. | A series of rigid polyphenylene, free-base porphyrin-containing dendrimers terminated with either dimethoxybenzene or benzoquinone end-groups were prepared by a combined divergent and convergent synthesis. Unlike previous routes for preparing polyphenylene dendrimers that are incompatible with end-groups bearing certai... |
12532305 | Synthesis of an amino-functionalized model of the Fe-only hydrogenase active site. | A dinuclear 2Fe2S mimic 6 of the active site of the Fe-only hydrogenases has been synthesized. Complex 6 contains a free amino group which enables linkage to a protein backbone or to a redox active species for the study of electron transfer processes in proteins or in supramolecular systems. The structures of the compl... |
12532304 | Dynamic chirality: keen selection in the face of stereochemical diversity in mechanically bonded compounds. | The template-directed syntheses, employing bisparaphenylene-[34]crown-10 (BPP34C10), 1,5-dinaphthoparaphenylene-[36]crown-10 (1/5NPPP36C10), and 1,5-dinaphtho-[38]crown-10 (1/5DNP38C10) as templates, of three [2]catenanes, whereby one of the two bipyridinium units in cyclobis(paraquat-p-phenylene) is replaced by a bipi... |
12532300 | Synthesis and structural analysis of the polymetallated alkali calixarenes [M4(p-tert-butylcalix[4]arene-4H)(thf)x]2.n THF (M=Li, K; n=6 or 1; x=4 or 5) and [Li2(p-tert-butylcalix[4]arene-2H)(H2O)(mu-H2O)(thf)].3 THF. | To study the structures and reactivities of alkali metallated intermediates of calix[4]arenes, three compounds were isolated: [Li(4)(p-tert-butylcalix[4]arene-4H)(thf)(4)](2).6 THF (1), [Li(2)(p-tert-butylcalix[4]arene-2H)(H(2)O)(mu-H(2)O)(thf)].3 THF (2), and [K(4)(p-tert-butylcalix[4]arene-4H)(thf)(5)](2).THF (3). Th... |
12532290 | Structural studies of N,N'-di(ortho-fluorophenyl)formamidine group 1 metallation. | The treatment of N,N'-di(ortho-fluorophenyl)formamidine (HFPhF) in tetrahydrofuran with equimolar amounts of n-butyllithium, sodium bis(trimethylsilyl)amide or potassium bis(trimethylsilyl)amide affords the colourless crystalline formamidinate complexes [Li(FPhF)(thf)] (1), [Na(FPhF)(thf)] (2) and [K(FPhF)] (5). Low-te... |
12530821 | Separation and quantitation of short-chain coenzyme A's in biological samples by capillary electrophoresis. | Because of the importance of coenzyme A's (CoA's or CoASH) in many metabolic processes and the biosynthesis of some carbohydrates and lipids, many methods have been developed to separate and determine their levels in various tissues for metabolism studies, including enzymatic assays, paper chromatography, and high-perf... |
12529528 | Proteomics of light-harvesting proteins in different plant species. Analysis and comparison by liquid chromatography-electrospray ionization mass spectrometry. Photosystem II. | An overview of the intact molecular masses and the hydrophobic properties of the photosystem II (PSII) light-harvesting proteins in 14 different plant species is presented. The protein separation and identification was achieved by means of reversed-phase high-performance liquid chromatography-electrospray ionization-ma... |
12529127 | Calix[4]arene-porphyrin conjugates as versatile molecular receptors for anions. | [structure: see text] Appending tetraphenylporphyrin units to the calix[4]arene skeleton via the ureido function leads to novel anion receptors designed for anion and/or cation detection by UV-vis spectroscopy. Calixarenes in the cone or 1,3-alternate conformations bearing two ureido moieties on the upper rim represent... |
12529117 | Novel antibiotics: macrocyclic peptides designed to trap Holliday junctions. | [reaction: see text] Described are the syntheses of eight macrocyclic peptides designed to trap Holliday junctions in bacteria, thereby inhibiting bacterial growth. These macrocycles were designed from linear dimerized hexapeptides that bind to the C-2 symmetrical Holliday junction. They were synthesized from three mon... |
12529448 | Regulation of vascular endothelial growth factor receptor-2 activity by caveolin-1 and plasma membrane cholesterol. | The stimulation of vascular endothelial growth factor receptor-2 (VEGFR-2) by tumor-derived VEGF represents a key event in the initiation of angiogenesis. In this work, we report that VEGFR-2 is localized in endothelial caveolae, associated with caveolin-1, and that this complex is rapidly dissociated upon stimulation ... |
12528985 | Molecular aspects of drug recognition by specific T cells. | Adverse reactions to drugs are a major problem in pharmacotherapy. About 1/6 of all side-effects are thought to be drug-induced immune-mediated reactions. It is well established that T and B cells recognize a drug if it is bound as hapten to carrier molecules. However, the model does not explain many T cell-mediated re... |
12527298 | Self-association equilibria of Escherichia coli UvrD helicase studied by analytical ultracentrifugation. | The Escherichia coli UvrD protein (helicase II) is an SF1 superfamily helicase required for methyl-directed mismatch repair and nucleotide excision repair of DNA. We have characterized quantitatively the self-assembly equilibria of the UvrD protein as a function of [NaCl], [glycerol], and temperature (5-35 degrees C; p... |
12526823 | Feeding liquid, non-ionic surfactant and cyclodextrin affect the properties of insulin-loaded poly(lactide-co-glycolide) microspheres prepared by spray-drying. | The potential of spray-drying technique for the encapsulation in poly(lactide-co-glycolide) (PLGA) microspheres of bovine insulin, a poorly stable peptide, has been investigated. Insulin-loaded microspheres were prepared by spray-drying different feeding liquids containing insulin and PLGA, that is a S/O dispersion, a ... |
12526677 | Secondary hypervalent I(III)...O interactions: synthesis and structure of hypervalent complexes of diphenyl-lambda3-iodanes with 18-crown-6. | Reported here for the first time are the synthesis and characterization of supramolecular complexes between diaryl-lambda(3)-iodanes and 18-crown-6 (18C6). Slow evaporation of solvents afforded 1:1 and 2:1 complexes between Ph(2)IBF(4) and 18C6 as stable crystals, depending on the conditions. X-ray crystal structures o... |
12526670 | Molecular recognition in (+)-alpha-pinene oxidation by cytochrome P450cam. | Oxygenated derivatives of the monoterpene (+)-alpha-pinene are found in plant essential oils and used as fragrances and flavorings. (+)-alpha-Pinene is structurally related to (+)-camphor, the natural substrate of the heme monooxygenase cytochrome P450(cam) from Pseudomonas putida. The aim of the present work was to ap... |
12526668 | Nanomolar inhibitors of AmpC beta-lactamase. | beta-lactamases are the most widespread resistance mechanism to beta-lactam antibiotics, such as the penicillins and the cephalosporins. In an effort to combat these enzymes, a combination of stereoselective organic synthesis, enzymology, microbiology, and X-ray crystallography was used to design and evaluate new carbo... |
12526663 | Evidence for vesicle formation during the synthesis of catanionic templated mesoscopically ordered silica as studied by Cryo-TEM. | The formation of vesicles during the synthesis of mesostructured surfactant-silicate materials has been evidenced for the first time by applying in situ Cryo-TEM. A mixture of anionic and cationic surfactants was used to fine-tune the packing parameter of the supramolecular surfactant assembly. It is shown that the ves... |
12526662 | Resorcinarenes as templates: a general strategy for the synthesis of large macrocycles. | The concept that resorcinarenes can be used as templates for the synthesis of large macrocycles is introduced. By way of example, previously inaccessible, aromatic crown ethers compounds are synthesized. |
12527184 | Non-surfactant nanospheres of progesterone inclusion complexes with amphiphilic beta-cyclodextrins. | Amphiphilic beta-cyclodextrins were formulated as nanospheres and characterised by particle size, zeta potential and TEM following freeze-fracture. The nanospheres were loaded with progesterone with different loading techniques involving the spontaneous formation of nanospheres from pre-formed inclusion complexes of am... |
12527166 | Efficacies of cyclodextrin-complexed and liposome-encapsulated clarithromycin against Mycobacterium avium complex infection in human macrophages. | Cyclodextrins and liposomes have been used in recent years as drug delivery vehicles, improving the bioavailability and therapeutic efficacy of many poorly water-soluble drugs. In this study, we used two approaches to enhance the availability of the poorly water-soluble antibiotic, clarithromycin, by inclusion complex ... |
12527162 | Bioavailability and efficacy characteristics of two different oral liquid formulations of albendazole. | The oral bioavailability and anthelmintic efficacy in mice of a new formulation of albendazole (ABZ) dissolved in a solution of hydroxypropyl-beta-cyclodextrin (HPCD) are compared with a conventional ABZ suspension of carboxymethylcellulose. Plasma concentrations of ABZ and albendazole sulphoxide (ABZ-SO), its active a... |
12527380 | Modulation of phosphoinositide 3-kinase activation by cholesterol level suggests a novel positive role for lipid rafts in lysophosphatidic acid signalling. | Methyl-beta-cyclodextrin (MbetaCD) was used to explore a role for cholesterol-enriched plasma membrane microdomains in coupling lysophosphatidic acid (LPA) stimulation to phosphoinositide 3-kinase (PI3K) activation. Cholesterol depletion strongly inhibited the production of phosphatidylinositol 3,4-bisphosphate and pho... |
12526716 | Structural effects of carbohydrate-containing polycations on gene delivery. 2. Charge center type. | Recent polycation structure-gene delivery studies reveal that subtle changes in the molecular structure of polycations have substantial influences on DNA-binding and condensation and on in vitro toxicity and gene delivery efficiency. In Part 1 of this structure-property study using carbohydrate-containing polycations (... |
12526715 | Structural effects of carbohydrate-containing polycations on gene delivery. 1. Carbohydrate size and its distance from charge centers. | Cationic polymers have the ability to bind plasmid DNA (pDNA) through electrostatic interactions and condense it into particles that can be readily endocytosed by cultured cells. The effects that polycation structure has on toxicity and gene delivery efficiency are investigated here by synthesizing a series of amidine-... |
12526705 | Synthesis and biological evaluation of folate receptor-targeted boronated PAMAM dendrimers as potential agents for neutron capture therapy. | Successful treatment of cancer by boron neutron capture therapy (BNCT) requires the selective delivery of (10)B to constituent cells within a tumor. The expression of the folate receptor is amplified in a variety of human tumors and potentially might serve as a molecular target for BNCT. In the present study we have in... |
12526703 | Synthetic approaches to multivalent lipopeptide dendrimers containing cyclic disulfide epitopes of foot-and-mouth disease virus. | The synthesis of a multiantigenic peptide dendrimer incorporating four copies of a cyclic disulfide epitope has been undertaken. Since standard chemoselective ligation procedures involving thioether formation are inadvisable in the presence of a preformed disulfide, conjugation through a peptide bond between the lipida... |
12526694 | Non-natural cell surface receptors: synthetic peptides capped with N-cholesterylglycine efficiently deliver proteins into Mammalian cells. | Protein toxins such as shiga toxin and cholera toxin penetrate into cells by binding small molecule-based cell surface receptors localized to cholesterol and sphingolipid-rich lipid raft subdomains of cellular plasma membranes. Molecular recognition between these toxins and their receptors triggers endocytic protein up... |
12526693 | Light-harvesting ionic dendrimer porphyrins as new photosensitizers for photodynamic therapy. | Photodynamic therapy (PDT) is a promising therapeutic modality for treatment of solid tumors. In this study, third-generation aryl ether dendrimer porphyrins (DPs) with either 32 quaternary ammonium groups (32(+)DPZn) or 32 carboxylic groups (32(-)DPZn) were evaluated as a novel, supramolecular class of photosensitizer... |
12525560 | Actin cytoskeletal dynamics in T lymphocyte activation and migration. | Dynamic rearrangements of the actin cytoskeleton are crucial for the function of numerous cellular elements including T lymphocytes. They are required for migration of T lymphocytes through the body to scan for the presence of antigens, as well as for the formation and stabilization of the immunological synapse at the ... |
12525167 | Enhanced membrane permeabilization and antibacterial activity of a disulfide-dimerized magainin analogue. | A cysteine substitution analogue of magainin-2 amide (magainin-F12W, N22C; denoted here as mag-N22C), and a disulfide-linked dimer prepared by air oxidation [(mag-N22C)(2)], were compared in their ability to release carboxyfluorescein (CF) from 100-nm large unilamellar vesicles (LUV) and to kill the Gram negative bacte... |
12525165 | Crystal structures of human prostatic acid phosphatase in complex with a phosphate ion and alpha-benzylaminobenzylphosphonic acid update the mechanistic picture and offer new insights into inhibitor design. | The X-ray crystal structure of human prostatic acid phosphatase (PAP) in complex with a phosphate ion has been determined at 2.4 A resolution. This structure offers a snapshot of the final intermediate in the catalytic mechanism and does not support the role of Asp 258 as a proton donor in catalysis. A total of eight h... |
12524311 | Surface charge density determines the efficiency of cationic gemini surfactant based lipofection. | The efficiencies of the binary liposomes composed of 1,2-dimyristoyl-sn-glycero-3-phosphocholine and cationic gemini surfactant, (2S,3R)-2,3-dimethoxy-1,4-bis(N-hexadecyl-N,N-dimethylammonium)butane dibromide as transfection vectors, were measured using the enhanced green fluorescent protein coding plasmid and COS-1 ce... |
12524310 | Variable symmetry in Salmonella typhimurium flagellar motors. | Electron cryomicroscopy of rotor complexes of the Salmonella typhimurium flagellar motor, overproduced in a nonmotile Escherichia coli host, has revealed a variation in subunit symmetry of the cytoplasmic ring (C ring) module. C rings with subunit symmetries ranging from 31 to 38 were found. They formed a Gaussian dist... |
12524302 | Fluorescence determination of tryptophan side-chain accessibility and dynamics in triple-helical collagen-like peptides. | We report tryptophan fluorescence measurements of emission intensity, iodide quenching, and anisotropy that describe the environment and dynamics at X and Y sites in stable collagen-like peptides of sequence (Gly-X-Y)(n). About 90% of tryptophans at both sites have similar solvent exposed fluorescence properties and a ... |
12524294 | Measuring distances in supported bilayers by fluorescence interference-contrast microscopy: polymer supports and SNARE proteins. | Fluorescence interference-contrast (FLIC) microscopy is a powerful new technique to measure vertical distances from reflective surfaces. A pattern of varying intensity is created by constructive and destructive interference of the incoming and reflected light at the surface of an oxidized silicon chip. Different levels... |
12519063 | Macrocyclization in the design of Grb2 SH2 domain-binding ligands exhibiting high potency in whole-cell systems. | While most SH2 domains bind phosphotyrosyl (pTyr) containing peptides in extended fashion, the growth factor receptor-bound protein 2 (Grb2) SH2 domain preferentially binds ligands in bend conformations. Accordingly, incorporation of bend-inducing functionality into synthetic ligands could potentially enhance their aff... |
12518224 | Expression of human papillomavirus type 6 L1 and L2 isolated in China and self assembly of virus-like particles by the products. | To study variations of genome late region of human papillomavirus type 6 (HPV-6) isolated in China and assembling capabilities of the encoded capsid proteins, HPV-6 L1 and L2 sequences were cloned and used for expression in Bac-to-Bac baculovirus expression systems (Gibco BRL). Based upon L1 and L2 overlapping sequence... |
12517177 | Macrocyclic glycoclusters. Self-aggregation and phosphate-induced agglutination behaviors of calix[4]resorcarene-based quadruple-chain amphiphiles with a huge oligosaccharide pool. | Macrocyclic glycocluster compounds 2n (n = 2-7) with four alkyl (undecyl) chains and eight oligosaccharide moieties on the opposite sides of the calix[4]resorcarene macrocycle are prepared from the reactions of the corresponding octaamine derivative with maltooligosaccharide lactones. Combined evidence from dynamic lig... |
12517168 | Intermolecular coupling in nanometric domains of light-harvesting dendrimer films studied by photoluminescence near-field scanning optical microscopy (PL NSOM). | Near-field scanning optical microscopy (NSOM) has been used to investigate the photophysical characteristics of first- to fourth-generation (G1 to G4) light-harvesting dendrimer thin films containing coumarin-343 and coumarin-2 as the core and peripheral chromophores, respectively. Thin film photoluminescence (PL) spec... |
12517157 | Supramolecular recognition. Terpyridyl palladium and platinum molecular clefts and their association with planar platinum complexes. | Molecular receptors, consisting of either two parallel cofacially disposed terpyridyl-Pd-Cl+ or terpyridyl-Pt-Cl+ units, are described. Concerted rotation of these units about the molecular spacer can alter their separation between 6.4 and 7.2 A to accommodate the dimensions of molecular guests. Neutral and anionic pla... |
14531723 | Absorption enhancers for nasal drug delivery. | This paper describes the basic concepts for the transmucosal delivery of drugs, and in particular the use of the nasal route for delivery of challenging drugs such as polar low-molecular-weight drugs and peptides and proteins. Strategies for the exploitation of absorption enhancers for the improvement of nasal delivery... |
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