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11222628 | Location of a constriction in the lumen of a transmembrane pore by targeted covalent attachment of polymer molecules. | Few methods exist for obtaining the internal dimensions of transmembrane pores for which 3-D structures are lacking or for showing that structures determined by crystallography reflect the internal dimensions of pores in lipid bilayers. Several approaches, involving polymer penetration and transport, have revealed limi... |
11226882 | Studies on the hydrolyzing mechanism for cyclodextrins of Thermoactinomyces vulgaris R-47 alpha-amylase 2 (TVAII). X-ray structure of the mutant E354A complexed with beta-cyclodextrin, and kinetic analyses on cyclodextrins. | Crystals of the mutant E354A of Thermoactinomyces vulgaris R-47 alpha-amylase 2 (TVAII) complexed with beta-cyclodextrin were prepared by a soaking method, and the diffraction data were collected at 100 K, using Synchrotron radiation (SPring-8). The crystals belong to an orthorhombic system with the space group P2(1)2(... |
11222617 | Construction and characterization of mutations at codon 751 of the Escherichia coli gyrB gene that confer resistance to the antimicrobial peptide microcin B17 and alter the activity of DNA gyrase. | Microcin B17 is a peptide antibiotic that inhibits DNA replication in Escherichia coli by targeting DNA gyrase. Previously, two independently isolated microcin B17-resistant mutants were shown to harbor the same gyrB point mutation that results in the replacement of tryptophan 751 by arginine in the GyrB polypeptide. W... |
11222606 | Regulatory architecture of the iron-regulated fepD-ybdA bidirectional promoter region in Escherichia coli. | The overlapping and opposing promoter elements for the Escherichia coli fepDGC operon and the ybdA gene (encoding a 43-kDa cytoplasmic membrane protein) within the enterobactin gene cluster were investigated by measuring the effects of site-specific mutations on transcript levels and on expression of reporter genes in ... |
11223146 | Succinylation of cyclodextrin glycosyltransferase from Thermoanaerobacter sp. 501 enhances its transferase activity using starch as donor. | A simple modification procedure, the succinylation of amino groups, was suitable to increase the transferase (disproportionation) activity of cyclodextrin glycosyltransferase (CGTase) from Thermoanaerobacter sp. 501 using different linear oligosaccharides as acceptors. On the contrary, the synthesis of cyclodextrins (C... |
11222320 | Spectroscopy on the B850 band of individual light-harvesting 2 complexes of Rhodopseudomonas acidophila. I. Experiments and Monte Carlo simulations. | The electronic structure of the circular aggregate of 18 bacteriochlorophyll a (BChl a) molecules responsible for the B850 absorption band of the light-harvesting 2 (LH2) complex of the photosynthetic purple bacterium Rhodopseudomonas acidophila has been studied by measuring fluorescence-excitation spectra of individua... |
11222309 | Effect of high pressure on the photochemical reaction center from Rhodobacter sphaeroides R26.1. | High-pressure studies on the photochemical reaction center from the photosynthetic bacterium Rhodobacter sphaeroides, strain R26.1, shows that, up to 0.6 GPa, this carotenoid-less membrane protein does not loose its three-dimensional structure at room temperature. However, as evidenced by Fourier-transform preresonance... |
11222298 | Lipid membrane expansion and micelle formation by polymer-grafted lipids: scaling with polymer length studied by spin-label electron spin resonance. | Spin-label electron spin resonance (ESR) spectroscopy and auxiliary optical density measurements are used to study lipid dispersions of N-poly(ethylene glycol)-dipalmitoyl phosphatidylethanolamine (PEG:5000-DPPE) mixed with dipalmitoyl phosphatidylcholine (DPPC). PEG:5000-DPPE bears a large hydrophilic polymer headgrou... |
11222297 | Amyloid-beta peptide assembly: a critical step in fibrillogenesis and membrane disruption. | Identifying the mechanisms responsible for the assembly of proteins into higher-order structures is fundamental to structural biology and understanding specific disease pathways. The amyloid-beta (Abeta) peptide is illustrative in this regard as fibrillar deposits of Abeta are characteristic of Alzheimer's disease. Bec... |
11179364 | Polarized entry of uropathogenic Afa/Dr diffusely adhering Escherichia coli strain IH11128 into human epithelial cells: evidence for alpha5beta1 integrin recognition and subsequent internalization through a pathway involving caveolae and dynamic unstable microtubules. | Afa/Dr diffusely adhering Escherichia coli strain IH11128 bacteria basolaterally entered polarized epithelial cells by a CD55- and CD66e-independent mechanism through interaction with the alpha5beta1 integrin and a pathway involving caveolae and dynamic microtubules (MTs). IH11128 invasion within HeLa cells was dramati... |
11179320 | Cytotoxic T lymphocyte antigen costimulation influences T-cell activation in response to Cryptococcus neoformans. | The kinetics of cytotoxic T lymphocyte antigen 4 (CTLA-4) expression on T cells responding to Cryptococcus neoformans and its role in regulating the T-cell response were examined. Using peripheral blood mononuclear cells stimulated with encapsulated or acapsular C. neoformans we showed that (i) the encapsulated strain ... |
11160750 | Elicitation of high-frequency cytotoxic T-lymphocyte responses against both dominant and subdominant simian-human immunodeficiency virus epitopes by DNA vaccination of rhesus monkeys. | Increasing evidence suggests that the generation of cytotoxic T-lymphocyte (CTL) responses specific for a diversity of viral epitopes will be needed for an effective human immunodeficiency virus type 1 (HIV-1) vaccine. Here, we determine the frequencies of CTL responses specific for the simian immunodeficiency virus Ga... |
11160747 | Interaction of coxsackievirus A21 with its cellular receptor, ICAM-1. | Coxsackievirus A21 (CAV21), like human rhinoviruses (HRVs), is a causative agent of the common cold. It uses the same cellular receptor, intercellular adhesion molecule 1 (ICAM-1), as does the major group of HRVs; unlike HRVs, however, it is stable at acid pH. The cryoelectron microscopy (cryoEM) image reconstruction o... |
11160716 | Self-assembly of nucleocapsid-like particles from recombinant hepatitis C virus core protein. | Little is known about the assembly pathway and structure of hepatitis C virus (HCV) since insufficient quantities of purified virus are available for detailed biophysical and structural studies. Here, we show that bacterially expressed HCV core proteins can efficiently self-assemble in vitro into nucleocapsid-like part... |
11170022 | Ocular tolerability and in vivo bioavailability of poly(ethylene glycol) (PEG)-coated polyethyl-2-cyanoacrylate nanosphere-encapsulated acyclovir. | Acyclovir-loaded polyethyl-2-cyanoacrylate (PECA) nanospheres were prepared by an emulsion polymerization process in the micellar phase and characterized. The influence of the presence of nonionic surfactant as well as other substances [i.e., 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CyD) and poly(ethylene glycol) (PE... |
11160097 | Role of the Tat ransport system in nitrous oxide reductase translocation and cytochrome cd1 biosynthesis in Pseudomonas stutzeri. | By transforming N2O to N2, the multicopper enzyme nitrous oxide reductase provides a periplasmic electron sink for a respiratory chain that is part of denitrification. The signal sequence of the enzyme carries the heptameric twin-arginine consensus motif characteristic of the Tat pathway. We have identified tat genes o... |
11181397 | Pharmacokinetics and safety of a 7-day administration of intravenous itraconazole followed by a 14-day administration of itraconazole oral solution in patients with hematologic malignancy. | The pharmacokinetics and safety of an intravenous hydroxypropyl-beta-cyclodextrin solution of itraconazole administered for 7 days followed by itraconazole oral solution administered at 200 mg once or twice daily for 14 days were assessed in 17 patients with hematologic malignancies. Steady-state plasma itraconazole co... |
11181391 | In vitro uptake of SCH 27899 (evernimicin) by rat alveolar macrophages. | The in vitro uptake of [(14)C]evernimicin ([(14)C]SCH 27899) by primary cultures of rat alveolar macrophages and hepatocytes was determined. Both cell populations exhibited linear rates of uptake. However, the initial rate of drug uptake by alveolar macrophages was about threefold higher than that by hepatocytes. These... |
11181372 | Antifungal activity and pharmacokinetics of posaconazole (SCH 56592) in treatment and prevention of experimental invasive pulmonary aspergillosis: correlation with galactomannan antigenemia. | The antifungal efficacy, safety, and pharmacokinetics of posaconazole (SCH 56592) (POC) were investigated in treatment and prophylaxis of primary pulmonary aspergillosis due to Aspergillus fumigatus in persistently neutropenic rabbits. Antifungal therapy consisted of POC at 2, 6, and 20 mg/kg of body weight per os; itr... |
11359794 | The mechanism of aubstrate eecognition of pyroglutamyl-peptidase I from Bacillus amyloliquefaciens as determined by X-ray crystallography and site-directed mutagenesis. | Pyroglutamyl-peptidase is able to specifically remove the amino-terminal pyroglutamyl residue protecting proteins or peptides from aminopeptidases. To clarify the mechanism of substrate recognition for the unique structure of the pyrrolidone ring, x-ray crystallography and site-directed mutagenesis were applied. The cr... |
11278795 | Cholesterol, a cell size-dependent signal that regulates glucose metabolism and gene expression in adipocytes. | Enlarged fat cells exhibit modified metabolic capacities, which could be involved in the metabolic complications of obesity at the whole body level. We show here that sterol regulatory element-binding protein 2 (SREBP-2) and its target genes are induced in the adipose tissue of several models of rodent obesity, suggest... |
11299067 | Close relationship of tissue plasminogen activator-plasminogen activator inhibitor-1 complex with multiple organ dysfunction syndrome investigated by means of the artificial pancreas. | <h4>Background</h4>Glucose tolerance (GT) has not been taken into consideration in investigations concerning relationships between coagulopathy and multiple organ dysfunction syndrome (MODS), and endothelial cell activation/endothelial cell injury (ECA/ECI) in septic patients, although coagulopathy is known to be influ... |
11251112 | Photoinduction of fast, reversible translational motion in a hydrogen-bonded molecular shuttle. | A rotaxane is described in which a macrocycle moves reversibly between two hydrogen-bonding stations after a nanosecond laser pulse. Observation of transient changes in the optical absorption spectrum after photoexcitation allows direct quantitative monitoring of the submolecular translational process. The rate of shut... |
11226240 | Destabilization of Ca2+-free gelsolin may not be responsible for proteolysis in Familial Amyloidosis of Finnish Type. | Mutations at position 187 in secreted gelsolin enable aberrant proteolysis at the 172-173 and 243-244 amide bonds, affording the 71-residue amyloidogenic peptide deposited in Familial Amyloidosis of Finnish Type (FAF). Thermodynamic comparisons of two different domain 2 constructs were carried out to study possible eff... |
11226229 | Viral capsid mobility: a dynamic conduit for inactivation. | Mass spectrometry and fluorescent probes have provided direct evidence that alkylating agents permeate the protein capsid of naked viruses and chemically inactivate the nucleic acid. N-acetyl-aziridine and a fluorescent alkylating agent, dansyl sulfonate aziridine, inactivated three different viruses, flock house virus... |
11278400 | Pou homeodomain protein OCT1 is implicated in the expression of the caudal-related homeobox gene Cdx-2. | The caudal homeobox gene Cdx-2 is a transcriptional activator for approximately a dozen genes specifically expressed in pancreatic islets and intestinal cells. It is also involved in preventing the development of colorectal tumors. Studies using "knockout" approaches demonstrated that Cdx-2 is haplo-insufficient in cer... |
11172063 | A second-generation vaccine protects against the psychoactive effects of cocaine. | The effects of immunization with the second-generation cocaine immunoconjugate GND-keyhole limpet hemocyanin (KLH) or with the anti-cocaine mAb GNC92H2 were assessed in a model of acute cocaine-induced locomotor activity. After i.p. administration of cocaine small middle dotHCl (15 mg/kg), rats were tested in photocell... |
29712017 | Dendron-Controlled Nucleation and Growth of Gold Nanoparticles. | Passivation of the metal surface by dendrons bearing a focal 4-pyridone functionality (the second-generation dendron is shown; C: gray, N: blue, O: red) allows controlled nucleation and growth of gold nanoclusters. The particle size is a direct function of the generation number of the dendritic ligands, with higher gen... |
23696441 | Ultrafast voltammetry of adsorbed redox active dendrimers with nanometric resolution: an electrochemical microtome. | Megavolt-per-second cyclic voltammetry is used to control the expansion with time of a diffusion layer created within the redox outer shell of a fourth generation dendrimer molecule adsorbed onto an electrode; one quarter of the dendrimer is shown in the picture. This allows the measurement of the degree of communicati... |
11180358 | Anion Recognition and Sensing: The State of the Art and Future Perspectives. | Anion recognition chemistry has grown from its beginnings in the late 1960s with positively charged ammonium cryptand receptors for halide binding to, at the end of the millennium, a plethora of charged and neutral, cyclic and acyclic, inorganic and organic supramolecular host systems for the selective complexation, de... |
12953590 | [Spectroscopy study on the photochromism of Schiff base N-salicylidene-1-hexadecylamine]. | The photochromism of N-Salicylidene-1-Hexadecylamine was studied by time-dependent fluorescence spectra, UV-Vis absorption spectra and theoretical chemistry calculation method. The photo-product was determined to be the keto form. The dynamics of the photochromism of the title compound was studied by the time course te... |
12525103 | [Nuclear ribosomal RNA small subunit (18S rRNA) nucleotide sequencing and characterization of sailonggu(whole bone of Myospalax baileyi Thomas)]. | <h4>Objective</h4>Sequencing the nuclear ribosomal RNA small subunit (18S rRNA) gene of Myospalax baileyi (Cricetidae) to develop an ultimate and definitive means for origin identification of genuine Sailonggu.<h4>Methods</h4>The total DNA was prepared from dried tail tissues. The nuclear 18S rRNA gene region was ampli... |
11300692 | Fluorometric studies on inclusion complexation of L/D-tryptophan by beta-cyclodextrin 6-O-pyridinecarboxylates. | Novel beta-cyclodextrin (beta-CD) derivatives, bearing a nicotinic or isonicotinic moiety, have been synthesized by a convenient method in 21 and 25% yields, respectively. The stability constants (K) and Gibbs free energy changes (-DeltaG degrees ) for the inclusion complexation of beta-cyclodextrin 6-O-mono(3-pyridine... |
11300691 | Stereoselective reduction with NADH model BNAH through chiral induction in cyclodextrins. | Stereoselective reductive debromination-cyclopropanation of 2-bromo-1-phenylethylidene-malononitrile and 2-bromo-1-beta-naphthylethylidenemalononitrile by coenzyme NADH model BNAH through chiral induction in cyclodextrins is reported. The matching between substrates and cyclodextrins, the substituent effect, and the ef... |
11573656 | Is pulmonary resistance constant, within the range of tidal volume ventilation, in patients with ARDS? | When managing patients with acute respiratory distress syndrome (ARDS), respiratory system compliance is usually considered first and changes in resistance, although recognized, are neglected. Resistance can change considerably between minimum and maximum lung volume, but is generally assumed to be constant in the tida... |
11462975 | Structure-activity relationships of pyridoxal phosphate derivatives as potent and selective antagonists of P2X1 receptors. | Novel analogues of the P2 receptor antagonist pyridoxal-5'-phosphate 6-azophenyl-2',5'-disulfonate (2) were synthesized and studied as antagonists in functional assays at recombinant rat P2X1, P2X2, and P2X3 receptors expressed in Xenopus oocytes (ion flux stimulation) and at turkey erythrocyte P2Y1 receptors (phosphol... |
11456776 | Supramolecular polar thin films built by surfactant liquid crystals: polarization-tunable multilayer self-assemblies with in-plane ferroelectric ordering of ion-based dipoles. | Polar order in the phosphonium liquid crystal thin films, which are composed of two-dimensional ion-pair-based domains separated by the insulating hydrocarbon layers, was probed by second harmonic generation (SHG) analysis. Despite the ordinary amphiphilic self-assemblies containing no pi-electron moieties, the solid-s... |
11456764 | Synthesis of ordered and disordered silicas with uniform pores on the border between micropore and mesopore regions using short double-chain surfactants. | Silica molecular sieves with uniform pores on the borderline between micropore (diameter <2 nm) and mesopore (from 2 to 50 nm) ranges were synthesized by a novel method using judiciously chosen mixtures of short double-chain alkylammonium surfactants. These silicas were characterized using X-ray diffraction (XRD), ther... |
11456629 | Polyfluorenes with polyphenylene dendron side chains: toward non-aggregating, light-emitting polymers. | A polyfluorene 12 has been prepared in which bulky polyphenylene dendrimer substituents suppress formation of long wavelength emitting aggregates, thus giving a polymer with pure blue emission. Absorption- and emission spectra and molecular modeling confirm that the bulky dendrimer side chains do not cause extra torsio... |
11430063 | Metal-mediated self-assembly of pyridylcalixarenes: prevention of intramolecular metal chelation is essential in constructing molecular capsules. | To construct calixarene-based molecular capsules utilizing the pyridyl-Pd(II) interaction, reactions of cone-pyridylcalix[4]arene 3, cone-pyridylcalix[5]arene 13, and cone-pyridylcalix[4]arene bis-crown 16 with square-planar Pd(II) complex 7 were investigated. Because of the coexistence of intermolecular binding and ch... |
11430091 | Diastereoselective synthesis of polysubstituted tetrahydropyrans and thiacyclohexanes via indium trichloride mediated cyclizations. | Polysubstituted tetrahydropyrans and thiacyclohexanes were synthesized in high yields with excellent diastereoselectivities via indium trichloride mediated cyclizations between homoallyl alcohols and mercaptans with aldehydes. In the case of tetrahydropyran products, the stereochemistry of the product was found to be d... |
11430090 | Asymmetric Baeyer-Villiger oxidations of 4-mono- and 4,4-disubstituted cyclohexanones by whole cells of engineered Escherichia coli. | Whole cells of an Escherichia coli strain that overexpresses Acinetobacter sp. NCIB 9871 cyclohexanone monooxygenase have been used for the Baeyer-Villiger oxidations of a variety of 4-mono- and 4,4-disubstituted cyclohexanones. In cases where comparisons were possible, this new biocatalytic reagent provided lactones w... |
11430083 | alpha-, beta-, and gamma-Cyclodextrin dimers. Molecular modeling studies by molecular mechanics and molecular dynamics simulations. | The alpha-, beta-, and gamma-cyclodextrin (CyD) dimers have been studied by molecular mechanics (MM) and molecular dynamics (MD) calculations, and the relative stability of dimers and the involved molecular interactions have been determined. Three possible orientations were considered for the alpha-, beta-, and gamma-C... |
11428012 | Exploiting the Curtin-Hammett principle--recognition-mediated acceleration of an aldol reaction. | [figure: see text] Curtin-Hammett-Winstein-Holness kinetics are exploited in the acceleration of the aldol reaction between formylbenzo-15-crown-5 and acetylbenzo-15-crown-5. Potassium cations facilitate this acceleration through the fast, reversible formation of a 1:1:1 sandwich complex between the crown ethers and th... |
11402732 | [Study on the inclusions of xindonin A-beta-cyclodextrin and xindonin B-beta-cyclodextrin]. | The inclusions compounds of Xindonin A-beta-cyclodextrin and Xindonin B-beta-cyclodextrin were prepared by the liquid-phase method in aqueous solution. They were confirmed by thin layer chromatography, differential thermal analysis and specific rotation. Changes of ultraviolet spectrum were determined. The composition ... |
11396282 | Prophylactic hemofiltration in severely traumatized patients: effects on post-traumatic organ dysfunction syndrome. | <h4>Objective</h4>To evaluate the effects of prophylactic veno-venous hemofiltration (CVVH) in the absence of renal failure on multiple organ dysfunction syndrome after severe multiple trauma.<h4>Design</h4>Prospective, randomized study.<h4>Setting</h4>Intensive care unit (ICU) in a university hospital.<h4>Patients</h4... |
11349289 | Hydrophobic interactions between spin-label 5-SASL and humic acid as revealed by ESR spectroscopy. | The spin-label probe 5-SASL (stearic acid spin-label with nitroxide free radical in position 5 of hydrocarbon chain), detectable by electron spin resonance (ESR), was tested to evaluate pH and reaction time dependencies of hydrophobic interactions with humic acid (HA). Strong changes were observed in 5-SASL ESR spectra... |
11345516 | Altered immunoreactivity of HPC-1/syntaxin 1A in proliferated nerve fibers in the human aganglionic colon of Hirschsprung's disease. | To clarify the pathogenesis of excessive proliferation of extrinsic nerve fibers in the aganglionic colon of patients with Hirschsprung's disease (HD), we immunohistochemically determined the role that exocytosis-related proteins play in the regulation of exocytosis using the antibody to HPC-1/syntaxin 1A, an exocytosi... |
11342157 | Physico-chemical analysis of lipid A fractions of lipopolysaccharide from Erwinia carotovora in relation to bioactivity. | Highly purified bisphosphoryl, monophosphoryl and dephosphoryl lipids A from Erwinia carotovora with different acylation patterns were characterized physico-chemically. Applying matrix assisted laser desorption/ionization mass spectrometry, the purity of the lipid A fractions was determined, and from monolayer measurem... |
11342144 | Cholesterol regulates membrane binding and aggregation by annexin 2 at submicromolar Ca(2+) concentration. | Annexin 2 is a member of the annexin family which has been implicated in calcium-regulated exocytosis. This contention is largely based on Ca(2+)-dependent binding of the protein to anionic phospholipids. However, annexin 2 was shown to be associated with chromaffin granules in the presence of EGTA. A fraction of this ... |
11312968 | Carbohydrate-based receptors with multiple thiourea binding sites. Multipoint hydrogen bond recognition of dicarboxylates and monosaccharides. | The binding properties of multitopic sugar thiourea receptors toward dicarboxylate and monosaccharide guests have been examined taking glutarate and octyl beta-D-glucopyranoside as model ligands. For the anionic hydrogen bond acceptor, both the complex stoichiometry and the association constants (K(as)) were found to b... |
11312943 | Ion-dipole S(N)2 reaction in acetone-water mixtures. Electrostatic and specific solute-solvent interactions. | The rate constants of the S(N)2 reaction of sodium 4-nitrophenoxide (1) and iodomethane were determined by UV-visible spectrophotometry in acetone-water mixtures at 25, 30, and 35 degrees C. The rate-Xwater (mole fraction of water) profile shows that the reaction depends strongly on the medium. The fastest rate constan... |
11301636 | Viscoelastic properties of human skin and processed dermis. | <h4>Background/aims</h4>The purpose of this work is to attempt to determine the elastic spring constant for collagen and elastic fibers (elastin) in skin and to determine if the values of these elastic constants are similar to those reported for other tissues.<h4>Methods</h4>We studied the viscoelastic mechanical prope... |
11302176 | The deletion of amino-terminal domain in Thermoactinomyces vulgaris R-47 alpha-amylases: effects of domain N on activity, specificity, stability and dimerization. | Thermoactinomyces vulgaris R-47 alpha-amylases, TVA I and TVA II, have a domain N, which is an extra structure in the family 13 enzymes. To investigate the roles of domain N in TVAs, we constructed TVAs-deltaN mutants which are deleted in domain N, and Y14,16,68A and Y41,82,95A mutants of TVA II. TVAs-deltaN were unsta... |
11296516 | The lipid world. | The continuity of abiotically formed bilayer membranes with similar structures in contemporary cellular life, and the requirement for microenvironments in which large and small molecules could be compartmentalized, support the idea that amphiphilic boundary structures contributed to the emergence of life. As an extensi... |
11293719 | Spectrochemical investigations in molecularly organized solvent media: evaluation of pyridinium chloride as a selective fluorescence quenching agent of polycyclic aromatic hydrocarbons in aqueous carboxylate-terminated poly(amido) amine dendrimers and anionic micelles. | The ability of pyridinium chloride (PC) to selectively quench alternant as opposed to nonaltemant polycyclic aromatic hydrocarbons (PAHs) in organized media is examined. PC was previously shown to be a selective quenching agent of alternant PAHs in neat polar solvents. Carboxylate-terminated poly(amido) amine (PAMAM-CT... |
11293696 | Quantitative determination of clenbuterol, salbutamol and tulobuterol enantiomers by capillary electrophoresis. | Enantiomers of clenbuterol, salbutamol and tulobuterol were directly separated and quantitated from a spiked sample by capillary electrophoresis (CE) using sulfaited beta-cyclodextrin (SCD) as chiral selector and phosphate as running buffer. The SCD and buffer concentration, pH and field strength were the parameters st... |
11289313 | Native skeletal muscle dihydropyridine receptor exists as a supramolecular triad complex. | One of the central elements of excitation-contraction coupling, the voltage-sensing dihydropyridine receptor, is believed to exist as a high-molecular-mass complex in the triad junction. Although freeze-fracture electron microscopical analysis suggests a tetrad complex, no direct biochemical evidence exists demonstrati... |
11289306 | Polyamines in cell growth and cell death: molecular mechanisms and therapeutic applications. | Polyamines are aliphatic cations with multiple functions and are essential for life. Cellular polyamine levels are regulated by multiple pathways such as synthesis from amino acid precursors, cellular uptake mechanisms that salvage polyamines from diet and intestinal microorganisms, as well as stepwise degradation and ... |
11282240 | Interaction of cationic partial dendrimers with charged and neutral liposomes. | Amphipathic partial dendrimers having three lipidic (C(14)) chains coupled to dendritic lysine head groups with eight, 16 or 32 free terminal amino groups have been synthesised by solid-phase peptide synthesis. Liposomes were prepared with positive, negative and neutral charge using the dehydration-rehydration method a... |
11282236 | Interfacial behaviour and micelle formation of novel amphiphilic sequential lipid-lysine oligomers. | As part of work on the design and synthesis of new supramolecular carrier systems for drugs, a series of novel linear oligomers of alternating alpha-amino tetradecanoic acid and lysine having positively charged groups and lipid chains was synthesised. The smallest member of the series (n=2) is insoluble in water and di... |
11266619 | Enantioselectivity in Candida antarctica lipase B: a molecular dynamics study. | A major problem in predicting the enantioselectivity of an enzyme toward substrate molecules is that even high selectivity toward one substrate enantiomer over the other corresponds to a very small difference in free energy. However, total free energies in enzyme-substrate systems are very large and fluctuate significa... |
11269530 | Enantiomeric separations of primary amino compounds by capillary electrochromatography with monolithic chiral stationary phases of chiral crown ether-bonded negatively charged polyacrylamide gels. | A novel enantiomeric separation method by capillary electrochromatography with chiral crown ether-bonded negatively charged polyacrylamide gels is presented. Two kinds of chiral crown ether derivatives, (+)-tetraallyl 18-crown-6 carboxylate and (+)-18-crown-6 tetracarboxylic acid 2-allyl ester were synthesized and allo... |
11269521 | Determination of RS,E/Z-tocotrienols by HPLC. | Synthetic alpha-tocotrienol was separated into four geometrical E/Z side chain isomers by preparative HPLC (permethylated beta-cyclodextrin phase). The isolated isomers were resolved in ethylene glycol dimethyl ether, converted into the corresponding methyl ether using dimethyl sulfate, and the tocotrienol methyl ether... |
11263875 | Model studies for molecular recognition of carbonic anhydrase and carboxypeptidase. | Model studies using Zn(2+) complexes of various derivatives of macrocyclic triamines ([12]aneN(3)) and tetraamines (cyclen) have been found to be useful in elucidating and understanding the intrinsic properties of substrate or inhibitor recognition by zinc ions at the active centers of carbonic anhydrase and carboxypep... |
11263869 | Metric engineering of soft molecular host frameworks. | The self-assembly and solid-state structures of host-guest inclusion compounds with lamellar architectures based on a common building block, a resilient hydrogen-bonded sheet consisting of guanidinium ions and sulfonate moieties of organodisulfonate "pillars", are described. The pillars connect adjacent sheets to gener... |
11264889 | Uric acid mediates photodynamic inactivation of caprine alpha-2-macroglobulin. | Uric acid (2,6,8 trioxopurine), the end product of purine metabolism in mammalian systems, has shown a wide range of antioxidant properties including scavenging of hydroxyl radical and singlet oxygen. In this study we show that in the presence of visible light, uric acid disrupted caprine alpha-2-macroglobulin (alpha(2... |
11266223 | Effects of grinding with microcrystalline cellulose and cyclodextrins on the ketoprofen physicochemical properties. | Ground mixtures of ketoprofen (KETO) with native crystalline beta-cyclodextrin, amorphous statistically substituted methyl-beta-cyclodextrin, and microcrystalline cellulose were investigated for both solid phase characterization (differential scanning calorimetry (DSC) powder X-ray diffractometry, and infrared (IR) spe... |
11262025 | Structure of a persistent heptachlorobornane in toxaphene (b7-1000) agrees with molecular model predictions. | A Cl(7) component of technical toxaphene (CTT), previously detected in marine mammals and fish and referred to as "7-1", was isolated from contaminated estuarine sediment using preparative solid-liquid chromatography followed by reversed-phase HPLC. The structure of this compound, elucidated by GC/MS and (1)H NMR, was ... |
11263569 | Rapid enantiomeric separation of polychlorinated biphenyls by electrokinetic chromatography using mixtures of neutral and charged cyclodextrin derivatives. | Electrokinetic chromatography with cyclodextrin derivatives (CD-EKC) was used to achieve the rapid enantiomeric separation of chiral polychlorinated biphenyls (PCBs). Thirteen of the 19 chiral PCBs stable at room temperature were individually separated into their two enantiomers by using 2-morpholinoethanesulfonic acid... |
11263568 | Separation of monomethyl-benz[a]anthracene isomers using cyclodextrin-modified electrokinetic chromatography. | Cyclodextrin-modified electrokinetic chromatography (CD-EKC) was investigated for the separation of 12 monomethylbenz[a]anthracene (MBA) isomers. Combined use of a polymeric surfactant, poly(sodium 10-undecenyl sulfate) (poly-SUS), with various types of neutral cyclodextrins (CDs) [beta-CD, gamma-CD, dimethyl-beta-CD (... |
11261667 | Beta-alanine-based dendritic beta-peptides: dendrimers possessing unusually strong binding ability towards protic solvents and their self-assembly into nanoscale aggregates through hydrogen-bond interactions. | A series of poly(beta-alanine) dendrimers 1-4 with Boc-carbamate as the surface functionality, beta-alanine as the dendritic branch, 3,5-diaminobenzoic acid as the branching agent, and 1,2diaminoethane as the interior core has been synthesized by a solution-phase peptide-coupling method. The structural identities and p... |
11261664 | Molecular recognition of carbohydrates by artificial receptors: systematic studies towards recognition motifs for carbohydrates. | The synthesis and binding properties for carbohydrates of several artificial, acyclic receptors containing two or three heterocyclic recognition units covalently attached to a phenyl spacer is described. These host molecules having uncharged hydrogen-bonding sites were used in a systematic study towards the evaluation ... |
11258764 | Enantiomer separation by strong anion-exchange capillary electrochromatography with dynamically modified sulfated beta-cyclodextrin. | A novel mode of capillary electrochromatography (CEC) based on a dynamically modified stationary phase was presented for chiral separation. The capillary column was packed with strong anion-exchange (SAX) stationary phase packing; the sulfated beta-cyclodextrin (S-CD), which was added to the mobile phase, was dynamical... |
11258761 | Analysis of metacycline by capillary electrophoresis. | The development and validation of an optimized capillary electrophoresis method for the determination of metacycline in the presence of its related substances by capillary electrophoresis is shown. The influence of methanol as organic modifier, buffer pH, buffer concentration, capillary length, column temperature, Trit... |
11258759 | Determination of nonsteroidal anti-inflammatory drugs in biological fluids by automatic on-line integration of solid-phase extraction and capillary electrophoresis. | A new, automatic method for the clean-up, preconcentration, separation, and quantitation of nonsteroidal anti-inflammatory drugs (NSAIDs) in biological samples (human urine and serum) using solid-phase extraction coupled on-line to capillary electrophoresis is proposed. Automatic pretreatment is carried out by using a ... |
11258758 | Capillary zone electrophoretic chiral discrimination using a cationic cyclodextrin derivative: determination of velocity and association constants of each enantiomer of the amino acid derivative with 6-trimethylammonio-deoxy-beta-cyclodextrin. | A positively charged beta-cyclodextrin possessing a trimethylammonio group, 6-trimethylammonio-6-deoxy-beta-cyclodextrin chloride 1 was prepared by the reaction of an amino derivative 3 with methyl iodide under very mild conditions. The cyclodextrin derivative discriminated between enantiomers of acetylphenylalanine 2 ... |
11258757 | Separation of multicomponent mixtures of 2,4-dinitrophenyl labelled amino acids and their enantiomers by capillary zone electrophoresis. | The use of capillary zone electrophoresis (CZE) for the separation of a group of 33 2,4-dinitrophenyl labeled amino acids (DNP-AA), including DNP-AA racemates, DNP-L-AA enantiomers and achiral DNP-AAs, was investigated. Alpha-, beta- and gamma-cyclodextrins (CDs) and their derivatives (hydroxypropyl derivatives of alph... |
11258702 | The histone H4 acetyltransferase MOF uses a C2HC zinc finger for substrate recognition. | Site-specific acetylation of histone H4 by MOF is central to establishing the hyperactive male X chromosome in Drosophila. MOF belongs to the MYST family of histone acetyltransferases (HATs) characterized by an unusual C2HC-type zinc finger close to their HAT domains. The function of these rare zinc fingers is unknown.... |
11258608 | Changes of cytokines in direct endotoxin adsorption treatment on postoperative multiple organ failure. | Multiple organ failure (MOF) is a serious condition that involves simultaneous or consecutive functional failure of several important organs. Furthermore, sepsis is known to play an important role in the occurrence of MOF. Hemoadsorption therapy with the endotoxin adsorption column containing polymyxin B immobilized fi... |
11258607 | Improved outcome prediction for patients with multiple organ failure undergoing continuous hemodiafiltration. | A number of patients with multiple organ failure (MOF) regardless of accompanying acute renal failure have been treated with continuous hemodiafiltration (CHDF). However, despite its high cost, the costs/benefits of CHDF for MOF patients still need to be evaluated. Although many scoring systems were established to pred... |
11251294 | Role of type II thioesterases: evidence for removal of short acyl chains produced by aberrant decarboxylation of chain extender units. | <h4>Background</h4>Modular polyketide synthases (PKSs) function as molecular assembly lines in which polyketide chains are assembled by successive addition of chain extension units. At the end of the assembly line, there is usually a covalently linked type I thioesterase domain (TE I), which is responsible for release ... |
11249120 | Effect of the complexation with cyclodextrins on the in vitro antiviral activity of ganciclovir against human cytomegalovirus. | The toxicity of the molecules currently used in the treatment of human cytomegalovirus (HCMV) in immunocompromised hosts often causes interruption of the therapy. Cyclodextrins (Cds), oligosaccharides possessing a hydrophobic cavity, have the property of forming inclusion complexes with a great number of molecules, imp... |
11246002 | In the mammalian eye type VI collagen tetramers form three morphologically different aggregates. | The organization of the aggregates occurring in the stroma: (1) of the murine and human cornea after incubation in an ATP acidic solution; (2) of surgically excised epiretinal membranes (ERM); and (3) of the trabecular meshwork of monkey eyes was investigated morphologically and immunocytochemically on thin section ele... |
11208784 | Effects exerted by transcriptional regulator PcaU from Acinetobacter sp. strain ADP1. | Protocatechuate degradation is accomplished in a multistep inducible catabolic pathway in Acinetobacter sp. strain ADP1. The induction is brought about by the transcriptional regulator PcaU in concert with the inducer protocatechuate. PcaU, a member of the new IclR family of transcriptional regulators, was shown to pla... |
11230151 | Targeting histone deacetylase complexes via KRAB-zinc finger proteins: the PHD and bromodomains of KAP-1 form a cooperative unit that recruits a novel isoform of the Mi-2alpha subunit of NuRD. | Macromolecular complexes containing histone deacetylase and ATPase activities regulate chromatin dynamics and are vitally responsible for transcriptional gene silencing in eukaryotes. The mechanisms that target these assemblies to specific loci are not as well understood. We show that the corepressor KAP-1, via its PHD... |
11241251 | Phase I bioequivalency study of MitoExtra and mitomycin C in patients with solid tumors. | <h4>Background</h4>This study compares serum pharmacokinetics, urinary excretion patterns, and relative bioequivalencies of single doses of MitoExtra (ME; SuperGen, San Ramon, CA) and mitomycin C (MMC).<h4>Methods</h4>Thirty-five patients were entered into this open-label, single-institution, crossover study with 2 tre... |
11235102 | Development of a thickness shear mode acoustic sensor based on an electrosynthesized molecularly imprinted polymer using an underivatized amino acid as the template. | The preparation and characterization of electrosynthesized poly(o-phenylenediamine) (iPoPD) as a molecular imprinting material were studied by an in situ quartz crystal impedance method. The changes of delta f0, delta R1, delta L1 and delta C0 suggest that the polymer film was compact and rigid. The thickness shear mod... |
11226408 | Localization of phospholipase C-gamma1 signaling in caveolae: importance in EGF-induced phosphoinositide hydrolysis but not in tyrosine phosphorylation. | Upon epidermal growth factor treatment, phospholipase C-gamma1 (PLC-gamma1) translocates from cytosol to membrane where it is phosphorylated at tyrosine residues. Caveolae are small plasma membrane invaginations whose structural protein is caveolin. In this study, we show that the translocation of PLC-gamma1 and its ty... |
11232860 | Stereospecific analysis of ecstasy-like N-ethyl-3,4-methylenedioxyamphetamine and its metabolites in humans. | A chiral HPLC method has been developed for the ecstasy analogue (R,S)-N-ethyl-3,4-methylenedioxyamphetamine (MDE) and its metabolites o-glucuronyl-(R,S)-N-ethyl-4-hydroxy-3-methoxyamphetamine (HME) and (R,S)-3,4-methylenedioxyamphetamine (MDA) in human plasma. The chiral discrimination of the compounds was carried out... |
11272729 | Supramolecular structure of self-assembled synthetic zinc-13(1)-oxo-chlorins possessing a primary, secondary or tertiary alcoholic 3(1)-hydroxyl group: visible spectroscopic and molecular modeling studies. | Zinc-chlorin 3 (see Fig. 2 in text) possessing a tertiary 3(1)-hydroxyl group and a 13-keto group was synthesized as a model for the antenna chlorophylls of green bacteria. Self-aggregation of 3 in nonpolar organic media was examined and compared to 1 and 2 possessing a primary and secondary 3(1)-hydroxyl group, respec... |
11273592 | National Surgical Adjuvant Breast and Bowel Project trials in colon cancer. | During the last decade, the National Surgical Adjuvant Breast and Bowel Project (NSABP) has completed six adjuvant chemotherapy trials comparing different adjuvant therapy regimens or adjuvant therapy versus surgery alone. A seventh trial is ongoing. These trials have contributed to defining the role of adjuvant therap... |
11272704 | A theoretical approach to the influence of the macrocycle conformation on the molecular electronic structure in Mg-porphyrins. | Nonplanar saddled (sad) ruffled (ruf) and domed (dom) conformations of the Mg-porphyrin (MgP) macrocycle in several degrees of deformation have been computed. These symmetrical distortion modes were induced in unsubstituted macrocycle using molecular definitions for calculations which permits us to achieve a systematic... |
11225110 | Systematic structural coordination chemistry of p-tert-butyltetrathiacalix[4]arene: 1. Group 1 elements and congeners. | Determinations of the crystal structures of complexes of the alkali metal ions with, in the case of Li, the dianion and, in the cases Na-Cs, the monoanion of p-tert-butyltetrathiacalix[4]arene have shown that both the sulfur atoms which form part of the macrocyclic ring, as well as the pendent phenolic/phenoxide oxygen... |
11171965 | Uncoupling proteins 2 and 3 are highly active H(+) transporters and highly nucleotide sensitive when activated by coenzyme Q (ubiquinone). | Based on the discovery of coenzyme Q (CoQ) as an obligatory cofactor for H(+) transport by uncoupling protein 1 (UCP1) [Echtay, K. S., Winkler, E. & Klingenberg, M. (2000) Nature (London) 408, 609-613] we show here that UCP2 and UCP3 are also highly active H(+) transporters and require CoQ and fatty acid for H(+) trans... |
11171953 | Double-level "orthogonal" dynamic combinatorial libraries on transition metal template. | Dynamic combinatorial libraries are mixtures of compounds that exist in a dynamic equilibrium and can be driven to compositional self adaptation via selective binding of a specific assembly of certain components to a molecular target. We present here an extension of this initial concept to dynamic libraries that consis... |
11160391 | Laminar organization of the NMDA receptor complex within the postsynaptic density. | The NR2 subunit is an essential component of the NMDA receptor. Recent biochemical research has identified a number of molecules that can bind directly or indirectly to its cytoplasmic tail. These postsynaptic density (PSD) proteins play a role in intracellular signal transduction, and are implicated in synaptic plasti... |
11178834 | Synthesis using ring closure metathesis and effect on nucleoside transport of a (N)-methanocarba S-(4-nitrobenzyl)thioinosine derivative. | [reaction: see text] A new synthetic route to ring-constrained (N)-methanocarba nucleosides and nucleotides is presented. Ring closure of a diene intermediate using Grubbs catalyst provides a new avenue for the preparation of the cyclopentenone derivative 6, which is a versatile intermediate for various carbocycles. Th... |
11178829 | Naphthalene-based calixarenes: unusual regiochemistry of a Friedel-Crafts alkylation. | [reaction: see text] In the pursuit of naphthalene-based calixarenes, a Friedel-Crafts alkylation with unusual regiochemistry was observed. Treatment of carbinol 14 with catalytic triflic acid was expected to produce calixarenes of the class represented by 16. Instead, the major product was cyclic trimer 15, in which a... |
11160944 | A novel multiple affinity purification tag and its use in identification of proteins associated with a cyclin-CDK complex. | A novel multiple affinity purification (MAFT) or tandem affinity purification (TAP) tag has been constructed. It consists of the calmodulin binding peptide, six histidine residues, and three copies of the hemagglutinin epitope. This 'CHH' MAFT tag allows two or three consecutive purification steps, giving high purity. ... |
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