id stringlengths 4 8 | title stringlengths 1 642 | abstract stringlengths 50 17.9k |
|---|---|---|
12885637 | Partitioning of individual flexible polymers into a nanoscopic protein pore. | Polymer dynamics are of fundamental importance in materials science, biotechnology, and medicine. However, very little is known about the kinetics of partitioning of flexible polymer molecules into pores of nanometer dimensions. We employed electrical recording to probe the partitioning of single poly(ethylene glycol) ... |
12885635 | CymA of Klebsiella oxytoca outer membrane: binding of cyclodextrins and study of the current noise of the open channel. | CymA, the outer membrane component of the cyclodextrin (CD) uptake and metabolism system of Klebsiella oxytoca, was reconstituted into lipid bilayer membranes. The channel properties of this unusual porin were studied in detail. The binding of CDs to the channel resulted in its complete block for ion transport. This re... |
12885633 | Structure-based prediction of potential binding and nonbinding peptides to HIV-1 protease. | HIV-1 protease is a major drug target against AIDS as it permits viral maturation by processing the gag and pol polyproteins of the virus. The cleavage sites in these polyproteins do not have obvious sequence homology or a binding motif and the specificity of the protease is not easily determined. We used various threa... |
12885629 | Effect of DNA superhelicity and bound proteins on mechanistic aspects of the Hin-mediated and Fis-enhanced inversion. | Using a recently developed inhomogeneous, macroscopic model for long DNA bound to proteins, we examine topological and geometric aspects of DNA/protein structures and dynamics on various stages of the Hin inversion pathway. This biological reaction involves exchange of DNA in a synaptic complex that brings together sev... |
12885628 | Insights into nucleic acid conformational dynamics from massively parallel stochastic simulations. | The helical hairpin is one of the most ubiquitous and elementary secondary structural motifs in nucleic acids, capable of serving functional roles and participating in long-range tertiary contacts. Yet the self-assembly of these structures has not been well-characterized at the atomic level. With this in mind, the dyna... |
12885627 | Lateral heterogeneity of photosystems in thylakoid membranes studied by Brownian dynamics simulations. | The aggregation and segregation of photosystems in higher plant thylakoid membranes as stromal cation-induced phenomena are studied by the Brownian dynamics method. A theoretical model of photosystems lateral movement within the membrane plane is developed, assuming their pairwise effective potential interaction in aqu... |
12884255 | Enhanced bioavailability of process-induced fast-dissolving ibuprofen cogranulated with beta-cyclodextrin. | The objectives of this study were to evaluate the bioavailability of cogranulated and oven-dried ibuprofen (IBU) and beta-cyclodextrin (betaCD), in comparison to a physical mixture, and to examine the effect of endogenous bile on the bioavailability of the drug. In vitro dissolution studies were performed using USP typ... |
12884243 | Innovations in oligonucleotide drug delivery. | Oligonucleotides (ONs) are a new class of therapeutic compounds under investigation for the treatment of a variety of disease states, such as cancer and HIV, and for FDA approval of an anti-CMV retinitis antisense molecule (Vitravene trade mark, Isis Pharmaceuticals). However, these molecules are limited not only by po... |
12883067 | Preterm birth among African American and white women: a multilevel analysis of socioeconomic characteristics and cigarette smoking. | <h4>Study objective</h4>Research shows that neighbourhood socioeconomic factors are associated with preterm delivery. This study examined whether cigarette smoking and individual socioeconomic factors modify the effects of neighbourhood factors on preterm delivery.<h4>Design</h4>Case-control study.<h4>Setting</h4>Moffi... |
12878390 | Effect of camphor/cyclodextrin complexation on the stability of O/W/O multiple emulsions. | Camphor (CA) encapsulation in oil/water/oil multiple emulsions prepared with cyclodextrin disturbs the emulsifier potential of alpha- and beta-natural cyclodextrins (CD). It was suggested that the size and geometrical fit between the CD cavity and CA could induce CD/CA complex formation in place of emulsifier formation... |
12879496 | Translational diffusion coefficient of cycloamylose in aqueous sodium hydroxide. | Seven cyclic (1 --> 4)-alpha-D-glucan (cycloamylose) samples ranging in weight-average molecular weight from 5 x 10(3) to 1.8 x 10(4) and gamma-cyclodextrin have been studied by sedimentation equilibrium in dimethylsulfoxide (at 25 degrees C) and by dynamic light scattering in 0.5 N aqueous sodium hydroxide (at 25 degr... |
12878523 | Heme binding contributes to antimalarial activity of bis-quaternary ammoniums. | Quaternary ammonium compounds have received recent attention due to their potent in vivo antimalarial activity based on their ability to inhibit de novo phosphatidylcholine synthesis. Here we show that in addition to this, heme binding significantly contributes to the antimalarial activity of these compounds. For the s... |
12876322 | Determination of membrane protein stability via thermodynamic coupling of folding to thiol-disulfide interchange. | Although progress has been made in understanding the thermodynamic stability of water-soluble proteins, our understanding of the folding of membrane proteins is at a relatively primitive level. A major obstacle to understanding the folding of membrane proteins is the discovery of systems in which the folding is in ther... |
12876316 | Stability of a 24-meric homopolymer: comparative studies of assembly-defective mutants of Rhodobacter capsulatus bacterioferritin and the native protein. | The stability of Rhodobacter capsulatus bacterioferritin, a 24-meric homopolymer, toward denaturation on variation in pH and temperature, and increasing concentrations of urea and guanidine.HCl was investigated with native PAGE, and CD and fluorescence spectroscopies. With temperature and urea, the wild-type protein de... |
12876314 | The role of geometric complementarity in secondary structure packing: a systematic docking study. | A strong similarity between the major aspects of protein folding and protein recognition is one of the emerging fundamental principles in protein science. A crucial importance of steric complementarity in protein recognition is a well-established fact. The goal of this study was to assess the importance of the steric c... |
12876308 | Identification of protein biochemical functions by similarity search using the molecular surface database eF-site. | The identification of protein biochemical functions based on their three-dimensional structures is strongly required in the post-genome-sequencing era. We have developed a new method to identify and predict protein biochemical functions using the similarity information of molecular surface geometries and electrostatic ... |
12876703 | Combination of transfection agents and magnetic resonance contrast agents for cellular imaging: relationship between relaxivities, electrostatic forces, and chemical composition. | The purpose of this study was to investigate the changes in electrostatic and magnetic resonance (MR) properties observed when MR contrast agents (CAs) (Feridex, MION-46L, or G5-dendrimer-DOTA-Gd) are combined with transfection agents (TAs) under various conditions for use as a CA-TA complex basis for cellular labeling... |
12875890 | A novel potentiometric approach for detection of beta-adrenergics and beta-adrenolytics in high-performance liquid chromatography. | Potentiometric approach enabling sensitive and reliable detection for a series of 20 autonomic beta-adrenergic ligands with the use of poly(vinyl chloride) (PVC) based liquid membrane electrode coatings in the normal-bore cation exchange HPLC and narrow-bore reversed phase HPLC system is presented. It was found that in... |
12874346 | Binding of Actinobacillus pleuropneumoniae to phosphatidylethanolamine. | The gram-negative bacterium Actinobacillus pleuropneumoniae is the causative agent of porcine fibrinohemorrhagic necrotizing pleuropneumonia, a disease that causes important economic losses to the swine industry worldwide. In general, the initial step of bacterial colonization is attachment to host cells. The purpose o... |
12874341 | Pseudomonas aeruginosa slime glycolipoprotein is a potent stimulant of tumor necrosis factor alpha gene expression and activation of transcription activators nuclear factor kappa B and activator protein 1 in human monocytes. | Pseudomonas aeruginosa, an opportunistic pathogen, causes infections associated with a high incidence of morbidity and mortality in immunocompromised hosts. Production of tumor necrosis factor alpha (TNF-alpha), primarily by cells of monocytic lineage, is a crucial event in the course of these infections. During in viv... |
12873522 | Early signal transduction events in specific plant disease resistance. | Gene-for-gene disease resistance in plants is initiated by highly specific molecular recognition processes, which often lead to a cell-death phenotype termed the hypersensitive response (HR). Recent studies have yielded insight into recognition events, and have begun to explain why the virulence and avirulence activiti... |
12593675 | Thermal stabilization of trypsin by enzymic modification with beta-cyclodextrin derivatives. | Streptoverticillum sp. transglutaminase was used as catalyst for the attachment of several beta-cyclodextrin derivatives to the glutamine residues in bovine pancreatic trypsin. The modifying agents used were mono-6-ethylenediamino-6-deoxy-beta-cyclodextrin, mono-6-propylenediamino-6-deoxy-beta-cyclodextrin, mono-6-buty... |
12871048 | The metabolism of diclofenac--enzymology and toxicology perspectives. | Diclofenac is a nonsteroidal anti-inflammatory drug bearing a carboxylic acid functional group. As a result, the metabolism of diclofenac in humans partitions between acyl glucuronidation and phenyl hydroxylation, with the former reaction catalyzed primarily by uridine 5'-diphosphoglucuronosyl transferase 2B7 while the... |
12871053 | A parallel synthesis demonstration library of tri-substituted indazoles containing new antimutagenic/antioxidant hits related to benzydamine. | A solution phase strategy for the multiple parallel synthesis of a demonstration library of indazoles is described by which regio-selectivity problems inherent to previous syntheses of this nucleus are largely overcome. Synthesis of selected components proceeded satisfactorily indicating that a fully realized library o... |
12869709 | Decreased peptidyltransferase activity correlates with increased programmed -1 ribosomal frameshifting and viral maintenance defects in the yeast Saccharomyces cerevisiae. | Increased efficiencies of programmed -1 ribosomal frameshifting in yeast cells expressing mutant forms of ribosomal protein L3 are unable to maintain the dsRNA "Killer" virus. Here we demonstrate that changes in frameshifting and virus maintenance in these mutants correlates with decreased peptidyltransferase activitie... |
12869705 | Stereospecificity of short Rev-derived peptide interactions with RRE IIB RNA. | The essential HIV-1 regulatory protein Rev binds to the Rev responsive element (RRE) of the HIV-1 mRNA. A short alpha-helical peptide derived from Rev (Rev 34-50) and a truncated form of the RRE sequence (RRE IIB) provide a useful in vitro system to study the interactions between Rev and RRE. The current studies focus ... |
12869203 | Physicochemical characterization and biological activity of a glycoglycerolipid from Mycoplasma fermentans. | We report a comprehensive physicochemical characterization of a glycoglycerolipid from Mycoplasma fermentans, MfGl-II, in relation to its bioactivity and compared this with the respective behaviors of phosphatidylcholine (PC) and a bacterial glycolipid, lipopolysaccharide (LPS) from deep rough mutant Salmonella minneso... |
12868069 | Caspase-independent cell death by low concentrations of nitric oxide in PC12 cells: involvement of cytochrome C oxidase inhibition and the production of reactive oxygen species in mitochondria. | We reported previously that low levels of nitric oxide (NO) induced cell death with properties of apoptosis, including chromatin fragmentation and condensation in undifferentiated PC12 pheochromocytoma cells. The present study demonstrates that cytotoxicity of low concentrations of NO is mediated by inhibition of mitoc... |
12867464 | The cellulosome system of Acetivibrio cellulolyticus includes a novel type of adaptor protein and a cell surface anchoring protein. | A scaffoldin gene cluster was identified in the mesophilic cellulolytic anaerobe Acetivibrio cellulolyticus. The previously described scaffoldin gene, cipV, encodes an N-terminal family 9 glycoside hydrolase, a family 3b cellulose-binding domain, seven cohesin domains, and a C-terminal dockerin. The gene immediately do... |
12867445 | TraG-like proteins of type IV secretion systems: functional dissection of the multiple activities of TraG (RP4) and TrwB (R388). | TraG-like proteins are essential components of type IV secretion systems. During secretion, TraG is thought to translocate defined substrates through the inner cell membrane. The energy for this transport is presumably delivered by its potential nucleotide hydrolase (NTPase) activity. TraG of conjugative plasmid RP4 is... |
12865660 | Copper stimulates the synthesis and release of interleukin-8 in human endothelial cells: a possible early role in systemic inflammatory responses. | Endogenous copper can play an important role in postischemic reperfusion injury, a condition associated with endothelial cell activation and increased interleukin 8 (IL-8) production. Excessive endothelial IL-8 secreted during trauma, major surgery, and sepsis may contribute to the development of systemic inflammatory ... |
12857928 | Dissection of cauliflower mosaic virus transactivator/viroplasmin reveals distinct essential functions in basic virus replication. | Cauliflower mosaic virus (CaMV) transactivator/viroplasmin (Tav) is an essential multifunctional viral protein. Dissection of Tav by deletion mutagenesis revealed that the central region is essential for CaMV replication in single cells but that the N- and C-terminal parts are not. Strains with mutations in the central... |
12857919 | A cellular receptor of human rhinovirus type 2, the very-low-density lipoprotein receptor, binds to two neighboring proteins of the viral capsid. | The very-low-density lipoprotein receptor (VLDL-R) is a receptor for the minor-group human rhinoviruses (HRVs). Only two of the eight binding repeats of the VLDL-R bind to HRV2, and their footprints describe an annulus on the dome at each fivefold axis. By studying the complex formed between a selection of soluble frag... |
12857911 | Overexpression of the alpha-2,6-sialyltransferase in MDCK cells increases influenza virus sensitivity to neuraminidase inhibitors. | No reliable cell culture assay is currently available for monitoring human influenza virus sensitivity to neuraminidase inhibitors (NAI). This can be explained by the observation that because of a low concentration of sialyl-alpha2,6-galactose (Sia[alpha2,6]Gal)-containing virus receptors in conventional cell lines, re... |
12857892 | Cholesterol depletion of human immunodeficiency virus type 1 and simian immunodeficiency virus with beta-cyclodextrin inactivates and permeabilizes the virions: evidence for virion-associated lipid rafts. | Recent evidence suggests that human immunodeficiency virus type 1 (HIV-1) particles assemble and bud selectively through areas in the plasma membrane of cells that are highly enriched with glycosylphosphatidylinositol-anchored proteins and cholesterol, called lipid rafts. Since cholesterol is required to maintain lipid... |
12851676 | Effects of N-acetyl-glucosamine-coated glycodendrimers as biological modulators in the B16F10 melanoma model in vivo. | Glyco-coat changes on cancer cells due to aberrant glycosylation are potential targets for immune recognition through lectin-like receptors on immune cells. These cells include natural killer (NK), CD8+ and CD4+ lymphocytes, all reported to have, together with cytokines, important functions in antitumor immunity. The a... |
12845565 | Glycocalyx morphology of Candida albicans. | In this study, we examine new cytochemical aspects of the fimbria-mediated adhesion of the oral facultative pathogen Candida albicans. A wild-type strain of the yeast was grown with and without sucrose supplementation for 8 days. Osmium tetroxide, uranyl acetate (UA), ruthenium red (RR), and cupromeronic blue (CB) stai... |
12842115 | Use of continuous-elution gel electrophoresis as a preparative tool for blot overlay analysis. | Blot overlay techniques have long been used to directly visualize protein-protein interactions within membrane complexes. However, this approach is often hampered by the limited quantities of purified membrane proteins available for conjugation with marker molecules. Here we applied continuous-elution gel electrophores... |
12842112 | Detection and analysis of membrane interactions by a biomimetic colorimetric lipid/polydiacetylene assay. | We describe applications of a colorimetric assay based on supramolecular assemblies of lipid-polydiacetylene vesicles for analysis and screening of membrane interactions of lipophilic enzymes, peptides, and ions and for study of the effects of lipid composition upon membrane properties. The lipid-polymer aggregates und... |
12840832 | Manifestation of chiral recognition of camphor enantiomers by alpha-cyclodextrin in longitudinal and transverse relaxation rates of the corresponding 1:2 complexes and determination of the orientation of the guest inside the host capsule. | The 1:2 complexes of camphor enantiomers with alpha-cyclodextrin in (2)H(2)O manifest differences in longitudinal and transverse relaxation rates of camphor methyl protons owing to chiral recognition. The relaxation data obtained at two magnetic fields were quantitatively analyzed using the model of anisotropic overall... |
12840820 | Tautomerism of 4-hydroxy-2,5-dimethyl-3(2H)-furanone: evidence for its enantioselective biosynthesis. | Chiral natural flavor compounds exhibit characteristic enantiomeric excesses due to stereoselective, enzymatically catalyzed reactions during biogenesis. Although the enzymatic formation of the strawberry key flavor compound 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF; Furaneol(R)) is anticipated, the naturally occurri... |
12782460 | A single-channel sensor based on gramicidin controlled by molecular recognition at bilayer lipid membranes containing receptor. | A novel ion-channel sensor based on a membrane bound receptor and a single gramicidin channel is described, in which the binding of an analyte to the membrane bound receptor modulates the single-channel activity of gramicidin. The sensor is composed of a planar bilayer lipid membrane (BLM) containing biotin-labeled pho... |
12888623 | Engineered biosynthesis of an ansamycin polyketide precursor in Escherichia coli. | Ansamycins such as rifamycin, ansamitocin, and geldanamycin are an important class of polyketide natural products. Their biosynthetic pathways are especially complex because they involve the formation of 3-amino-5-hydroxybenzoic acid (AHBA) followed by backbone assembly by a hybrid nonribosomal peptide synthetase/polyk... |
12974973 | Intravenous colistin in the treatment of sepsis from multiresistant Gram-negative bacilli in critically ill patients. | <h4>Introduction</h4>The increasing prevalence of multiresistant Gram-negative strains in intensive care units (ICUs) has recently rekindled interest in colistin, a bactericidal antibiotic that was used in the 1960s for treatment of infections caused by Gram-negative bacilli. We conducted the present observational stud... |
12886016 | Identification of Plasmodium falciparum antigens by antigenic analysis of genomic and proteomic data. | The recent explosion in genomic sequencing has made available a wealth of data that can now be analyzed to identify protein antigens, potential targets for vaccine development. Here we present, in the context of Plasmodium falciparum, a strategy that rapidly identifies target antigens from large and complex genomes. Si... |
12886020 | Conjugation to gold nanoparticles enhances polyethylenimine's transfer of plasmid DNA into mammalian cells. | Branched polyethylenimine (PEI) chains with an average molecular mass of 2 kDa (PEI2) have been covalently attached to gold nanoparticles (GNPs), and the potency of the resulting PEI2-GNPs conjugates as vectors for the delivery of plasmid DNA into monkey kidney (COS-7) cells in the presence of serum in vitro has been s... |
12885870 | Vav1 phosphorylation is induced by beta2 integrin engagement on natural killer cells upstream of actin cytoskeleton and lipid raft reorganization. | The guanine nucleotide exchange factor Vav1 regulates actin polymerization and contributes to cytotoxicity by natural killer (NK) cells. An open question is how Vav1 becomes activated and what receptor can signal upstream of actin cytoskeleton rearrangement upon NK cell contact with target cells. Using transfected inse... |
12882962 | Reaction intermediate structures of 1-aminocyclopropane-1-carboxylate deaminase: insight into PLP-dependent cyclopropane ring-opening reaction. | The pyridoxal 5'-phosphate-dependent enzymes have been evolved to catalyze diverse substrates and to cause the reaction to vary. 1-Aminocyclopropane-1-carboxylate deaminase catalyzes the cyclopropane ring-opening reaction followed by deamination specifically. Since it was discovered in 1978, the enzyme has been widely ... |
12882964 | Phosphatidylinositol 3-kinase interacts with the adaptor protein Dab1 in response to Reelin signaling and is required for normal cortical lamination. | Reelin is a large secreted signaling protein that binds to two members of the low density lipoprotein receptor family, the apolipoprotein E receptor 2 and the very low density lipoprotein receptor, and regulates neuronal positioning during brain development. Reelin signaling requires activation of Src family kinases as... |
12897994 | Omega-3 vs. omega-6 lipid emulsions exert differential influence on neutrophils in septic shock patients: impact on plasma fatty acids and lipid mediator generation. | <h4>Objective</h4>To compare the effects of a conventional omega-6 lipid infusion and a fish oil based (omega-3) lipid infusion for parenteral nutrition on neutrophil function, lipid mediators, and plasma free fatty acids.<h4>Design and setting</h4>Open-label, randomized, pilot study in a university hospital medical in... |
12881487 | A kinase-regulated mechanism controls CFTR channel gating by disrupting bivalent PDZ domain interactions. | Dynamic regulation of ion channels is critical for maintaining fluid balance in epithelial tissues. Cystic fibrosis, a genetic disease characterized by impaired fluid transport in epithelial tissues, is caused by dysfunctional cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channel activity. Recent studi... |
12878594 | Unfolding of Vibrio cholerae hemolysin induces oligomerization of the toxin monomer. | Vibrio cholerae hemolysin (HlyA) is a pore-forming toxin that exists in two stable forms: a hemolytically active water-soluble monomer with a native molecular weight of 65,000 and a hemolytically inactive SDS-stable heptamer with the configuration of a transmembrane diffusion channel. Transformation of the monomer into... |
12909776 | Benzylation and nitrosation of 4-amino-2-(methylsulfanyl)pyrimidin-6(1H)-one: two P2(1)/c polymorphs of 4-amino-1-benzyl-2-(methylsulfanyl)pyrimidin-6(1H)-one with Z' = 1 and 2, 4-amino-6-benzyloxy-2-(methylsulfanyl)pyrimidine and 4-amino-1-benzyl-2-(methylsulfanyl)-5-nitrosopyrimidin-6(1H)-one all give different hydro... | 4-Amino-1-benzyl-2-(methylsulfanyl)pyrimidin-6(1H)-one, C(12)H(13)N(3)OS, crystallizes in two polymorphic forms, both having space group P2(1)/c, with Z' = 1 for form (I) and Z' = 2 for form (II). In (I), the molecules are linked by a single N-H.O hydrogen bond into simple C(6) chains, which are themselves linked into ... |
12909757 | Potassium dicyanoargentate(I) 1,4,7,10,13,16-hexaoxacyclooctadecane. | The crystal structure of the title compound, K[Ag(CN)(2)].C(12)H(24)O(6), conventionally denoted K(18-crown-6)Ag(CN)(2), where 18-crown-6 is 1,4,7,10,13,16-hexaoxacyclooctadecane, is characterized by closely packed linear chains formed by the coordination of the nitrile N atoms of the [Ag(CN)(2)](-) anions to the K(+) ... |
12879186 | Determination of lead and cadmium using a polycyclodextrin-modified carbon paste electrode with anodic stripping voltammetry. | This work reports the use of alpha and beta-cyclodextrin-modified carbon paste electrodes (CPE(alpha-CD) and CPE(beta-CD)) to determine simultaneously Pb(II) and Cd(II) by means of the electrochemical technique known as anodic stripping voltammetry (ASV). Both modified electrodes displayed good resolution of the oxidat... |
12879239 | Pyrrolidine dithiocarbamate attenuates the development of organ failure induced by zymosan in mice. | <h4>Objective</h4>Nuclear factor (NF) kappaB is a transcription factor which plays a pivotal role in the induction of genes involved in physiological processes as well as in the response to injury and inflammation. Dithiocarbamates are anti-oxidants which are potent inhibitors of NF-kappaB. We postulated that pyrrolidi... |
12867594 | Electrochemical interrogation of conformational changes as a reagentless method for the sequence-specific detection of DNA. | We report a strategy for the reagentless transduction of DNA hybridization into a readily detectable electrochemical signal by means of a conformational change analogous to the optical molecular beacon approach. The strategy involves an electroactive, ferrocene-tagged DNA stem-loop structure that self-assembles onto a ... |
12865394 | Modulation of the multidrug resistance (MDR) system in the nematode Haemonchus contortus by changing cholesterol content: effects on resistance to anthelmintics. | <h4>Objectives</h4>The efficiency of the anthelmintics used to treat small domestic ruminants infected with nematodes is compromised by the emergence of resistant parasites. Both specific and non-specific mechanisms of resistance exist. The non-specific mechanisms involve multiple resistance phenomena and are dependent... |
12859795 | Sensitivity and fidelity of DNA microarray improved with integration of Amplified Differential Gene Expression (ADGE). | <h4>Background</h4>The ADGE technique is a method designed to magnify the ratios of gene expression before detection. It improves the detection sensitivity to small change of gene expression and requires small amount of starting material. However, the throughput of ADGE is low. We integrated ADGE with DNA microarray (A... |
12860933 | Mutation in fas ligand impairs maturation of thymocytes bearing moderate affinity T cell receptors. | Fas ligand, best known as a death-inducer, is also a costimulatory molecule required for maximal proliferation of mature antigen-specific CD4+ and CD8+ T cells. We now extend the role of Fas ligand by showing that it can also influence thymocyte development. T cell maturation in some, but not all, strains of TCR transg... |
12909749 | A new Na/Mg inverse crown ether. | A 'missing' member of the inverse crown ether family, namely mu(4)-oxo-tetrakis(mu-2,2,6,6-tetramethylpiperidinido)dimagnesium(II)disodium(I), [Na(2)Mg(2)O(C(9)H(18)N)(4)], has been synthesized by blocking the alternative aromatic metallation route via the use of sterically hindered 1,3,5-mesitylene as a solvent. [Na(2... |
14517334 | Part of Ran is associated with AKAP450 at the centrosome: involvement in microtubule-organizing activity. | The small Ran GTPase, a key regulator of nucleocytoplasmic transport, is also involved in microtubule assembly and nuclear membrane formation. Herein, we show by immunofluorescence, immunoelectron microscopy, and biochemical analysis that a fraction of Ran is tightly associated with the centrosome throughout the cell c... |
14517317 | Specificity of binding of the plectin actin-binding domain to beta4 integrin. | Plectin is a major component of the cytoskeleton and links the intermediate filament system to hemidesmosomes by binding to the integrin beta4 subunit. Previously, a binding site for beta4 was mapped on the actin-binding domain (ABD) of plectin and binding of beta4 and F-actin to plectin was shown to be mutually exclus... |
14517311 | Cell surface orifices of caveolae and localization of caveolin to the necks of caveolae in adipocytes. | Caveolae are noncoated invaginations of the plasma membrane that form in the presence of the protein caveolin. Caveolae are found in most cells, but are especially abundant in adipocytes. By high-resolution electron microscopy of plasma membrane sheets the detailed structure of individual caveolae of primary rat adipoc... |
12857958 | Chirality sensing by Escherichia coli topoisomerase IV and the mechanism of type II topoisomerases. | Escherichia coli topoisomerase (Topo) IV is an essential type II Topo that removes DNA entanglements created during DNA replication. Topo IV relaxes (+) supercoils much faster than (-) supercoils, promoting replication while sparing the essential (-) supercoils. Here, we investigate the mechanism underlying this chiral... |
12857950 | Ubiquitin-mediated sequestration of normal cellular proteins into polyglutamine aggregates. | A hallmark of most neurodegenerative diseases, including those caused by polyglutamine expansion, is the formation of ubiquitin (Ub)-positive protein aggregates in affected neurons. This finding suggests that the Ub system may be involved in common mechanisms underlying these otherwise unrelated diseases. Here we repor... |
12855767 | Resolving intermediates in biological proton-coupled electron transfer: a tyrosyl radical prior to proton movement. | The coupling of proton chemistry with redox reactions is important in many enzymes and is central to energy transduction in biology. However, the mechanistic details are poorly understood. Here, we have studied tyrosine oxidation, a reaction in which the removal of one electron from the amino acid is linked to the rele... |
12855766 | Electrostatic complementarity in an aldose reductase complex from ultra-high-resolution crystallography and first-principles calculations. | The electron density and electrostatic potential in an aldose reductase holoenzyme complex have been studied by density functional theory (DFT) and diffraction methods. Aldose reductase is involved in the reduction of glucose in the polyol pathway by using NADPH as a cofactor. The ultra-high resolution of the diffracti... |
14676984 | Collective behaviour of crown channels. | Collective behaviour of a crown ether channel, bis[(benzo-15-crown-5)-15- yl methyl] pimelate, in a planar lipid bilayer membrane has been studied through electrophysiological methods. A characteristic feature of these channels is their sequential opening, indicated by a uniform stepwise increase in the multi-channel c... |
12955455 | Chloroplast RNA-binding proteins. | Chloroplast gene expression is regulated by nucleus-encoded factors, which mainly act at the post-transcriptional level. Plastid RNA-binding proteins (RBPs) represent good candidates for mediating these functions. The picture emerging from recent analyses is that of a great number of differentially regulated RBPs, whic... |
12853566 | Like-charge attraction between polyelectrolytes induced by counterion charge density waves. | Electrostatics in aqueous media is commonly understood in terms of screened Coulomb interactions, where like-charged objects, such as polyelectrolytes, always repel. These intuitive expectations are based on mean field theories, such as the Poisson-Boltzmann formalism, which are routinely used in colloid science and co... |
12851396 | Biological activities and pore formation of Clostridium perfringens beta toxin in HL 60 cells. | Clostridium perfringens beta toxin is an important agent of necrotic enteritis. Of the 10 cell lines tested, only the HL 60 cell line was susceptible to beta toxin. The toxin induced swelling and lysis of the cell. Treatment of the cells with the toxin resulted in K+ efflux from the cells and Ca2+, Na+, and Cl- influxe... |
12848903 | Identification of a distinct class of cytoskeleton-associated mRNAs using microarray technology. | <h4>Background</h4>Interactions between mRNA and the cytoskeleton are critical for the localization of a number of transcripts in eukaryotic somatic cells. To characterize additional transcripts that may be subject to this form of regulation, we developed a two-step approach that utilizes biochemical fractionation of c... |
12848892 | Distal hinge of plasminogen activator inhibitor-1 involves its latency transition and specificities toward serine proteases. | <h4>Background</h4>The plasminogen activator inhibitor-1 (PAI-1) spontaneously converts from an inhibitory into a latent form. Specificity of PAI-1 is mainly determined by its reactive site (Arg346-Met347), which interacts with serine residue of tissue-type plasminogen activator (tPA) with concomitant formation of SDS-... |
12844485 | Chemopreventive n-3 fatty acids activate RXRalpha in colonocytes. | The underlying mechanisms by which n-3 polyunsaturated fatty acids (PUFA) exert a chemopreventive effect in the colon have not been elucidated. Retinoid X receptors (RXR) are a family of nuclear receptors implicated in cancer chemoprevention. Since docosahexaenoic acid (DHA), an n-3 PUFA enriched in fish oil, reduces c... |
12843404 | A ring of eight conserved negatively charged amino acids doubles the conductance of BK channels and prevents inward rectification. | Large-conductance Ca2+-voltage-activated K+ channels (BK channels) control many key physiological processes, such as neurotransmitter release and muscle contraction. A signature feature of BK channels is that they have the largest single channel conductance of all K+ channels. Here we examine the mechanism of this larg... |
12835337 | Salt of the earth or a drop in the ocean? A pathophysiological approach to fluid resuscitation. | The evolved endocrine response after injury leads to sodium, chloride, and water retention at a time when large volumes of sodium containing fluids are given to maintain the circulation and preserve tissue oxygenation. Sodium, chloride, and water are also retained because of increased systemic vascular permeability to ... |
14677640 | New designs for MRI contrast agents. | New designs for Magnetic Resonance Imaging contrast agents are presented. Essentially, they all are host-guest inclusion complexes between y-cyclodextrins and polyazamacrocycles of gadolinium (III) ion. Substitutions have been made to the host to optimise the host-guest association. Molecular mechanics calculations hav... |
12678808 | Towards more efficient glutathione peroxidase mimics: substrate recognition and catalytic group assembly. | Glutathione peroxidase (GPX) is a well-known selenoenzyme that functions as an antioxidant and catalyzes the reduction of harmful peroxide by glutathione and protects cells against oxidative damage. Because many diseases are related to oxidative stress, GPX is an ancient foe of many diseases. Antioxidants are very usef... |
14658662 | Specific interactions study in complexes of poly(mono-n-alkyl itaconates) with tertiary polyamides. | This paper reports an FT-IR study of blends of poly(mono-n-alkyl itaconates) with poly(N,N-dimethylacrylamide) (PDMA) and poly(ethyloxazoline) (PEOX). Strong hydrogen bonding has been found, and both polybases have shown similar acceptor strengths. Derivative techniques show asymmetric profiles for the free carbonyl ba... |
15369357 | Total synthesis of anti-HIV agent chloropeptin I. | A convergent diastereo- and enantioselective total synthesis of anti-HIV agent chloropeptin I is reported. Important features of the total synthesis include: (1) the use of Ti-catalyzed cyanide addition to imines to prepare a requisite amino acid moiety, (2) the discovery of the positive effect of MeOH in the Cu-mediat... |
15369344 | Protein electrochemistry using aligned carbon nanotube arrays. | The remarkable electrocatalytic properties and small size of carbon nanotubes make them ideal for achieving direct electron transfer to proteins, important in understanding their redox properties and in the development of biosensors. Here, we report shortened SWNTs can be aligned normal to an electrode by self-assembly... |
15369332 | Use of abasic site-containing DNA strands for nucleobase recognition in water. | Nucleobase recognition in water is successfully achieved by the use of an abasic site (AP site) as the molecular recognition field. We intentionally construct the AP site in DNA duplex so as to orient the AP site toward a target nucleobase and examine the complexation of 2-amino-7-methylnaphthyridine (AMND) with nucleo... |
15369329 | Colorimetric reversibility of polydiacetylene supramolecules having enhanced hydrogen-bonding under thermal and pH stimuli. | To investigate the role of hydrogen-bonding on colorimetric transition of polydiacetylene supramolecules, novel diacetylene derivatives allowing various hydrogen-bonding states were synthesized by coupling carboxy-substituted (ortho-, meta-, and para-) anilide groups with a typical single-chain diacetylene lipid. One w... |
14570218 | Gas adsorption gates based on ultrathin composite polymer films. | High surface area alumina coatings were prepared on surface acoustic wave (SAW) mass balances. These coatings were fabricated by anodic etching of evaporated aluminum films. The coatings consisted of roughly collinear pores penetrating through the monolithic alumina film. The nanoporous (NP) coatings were characterized... |
14518565 | Effects of OP-1206 alpha-CD on walking dysfunction in the rat neuropathic intermittent claudication model: comparison with nifedipine, ticlopidine and cilostazol. | The systemic treatment effects of OP-1206 alpha-CD (17S-20-dimethyl-trans-delta 2-PGE1 alpha-cyclodextrin clathrate), a prostaglandin E1 (PGE1) analogue, on walking dysfunction, spinal cord blood flow (SCBF) and skin blood flow (SKBF) were assessed in the rat neuropathic intermittent claudication (IC) model in comparis... |
14502435 | Comparative pharmacology of the activity of wild-type and G551D mutated CFTR chloride channel: effect of the benzimidazolone derivative NS004. | The pharmacological activation of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel mutated at glycine 551 (G551D-CFTR) was studied in the presence of the benzimidazolone derivative NS004 and compared to that of wild-type (wt) CFTR. Using iodide ((125)I) efflux and whole-cell patch-clamp t... |
14502434 | Identification of caveolae-like structures on the surface of intact cells using scanning force microscopy. | Caveolae are small, functionally important membrane invaginations found on the surface of many different cell types. Using electron microscopy, caveolae can be unequivocally identified in cell membranes by virtue of their size and the presence of caveolin/VIP22 proteins in the caveolar coat. In this study we have appli... |
12840020 | Complexes of matrilin-1 and biglycan or decorin connect collagen VI microfibrils to both collagen II and aggrecan. | Native supramolecular assemblies containing collagen VI microfibrils and associated extracellular matrix proteins were isolated from Swarm rat chondrosarcoma tissue. Their composition and spatial organization were characterized by electron microscopy and immunological detection of molecular constituents. The small leuc... |
12956085 | Syntheses of dendritic branches based on L-lysine: is the stereochemistry preserved throughout the synthesis? | This paper reports the syntheses of individual dendritic branches based on L-lysine and functionalised with either Boc or Bz surface groups. Convergent and divergent synthetic approaches were employed and the preservation of stereochemistry during the syntheses was monitored using polarmetry, NMR and HPLC. In addition,... |
12956083 | Complexation of phenolic guests by endo- and exo-hydrogen-bonded receptors. | This article describes the complexation of phenol derivatives by hydrogen-bonded receptors. These phenol receptors are formed by self-assembly of calix[4]arene dimelamine or tetramelamine derivatives with 5,5-diethylbarbiturate (DEB) or cyanurate derivatives (CYA). The double rosette assemblies 3(3).(DEB)6/(CYA)6 have ... |
12956082 | Investigation of the complexation of (+)-catechin by beta-cyclodextrin by a combination of NMR, microcalorimetry and molecular modeling techniques. | (+)-Catechin is a polyphenolic compound of natural origin that presents anti-oxidant properties of interest for therapeutics or cosmetics uses. Preliminary studies on inclusion into cyclodextrin cavities yielded contradictory results both for the quantitative (affinity constant) and qualitative description of the inter... |
12950061 | Enhancement effect of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and cationic surfactant on the chemiluminescence of poly(3, 4, 5-trihydroxybenzoate ester)dendrimers. | In the presence of l-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), the chemiluminescence (CL) intensities of poly(3, 4, 5-trihydroxybenzoateester)dendrimers, 1 and 2, having 1,2-pyrocatechol and 1,3,5-trihydroxybenzene as core molecules and also six and nine gallic acid units in the periphery, were respectively 7.... |
12945691 | Isolation of an inclusion complex of naphthol and its benzoate as an intermediate in the solvent-free benzoylation reaction of naphthol. | Solvent-free benzoylation of naphthol was found to proceed via an inclusion complex intermediate of the naphthol and its benzoate by IR spectral monitoring. |
12945689 | Electrontransfer through DNA and metal-containing DNA. | DNA is currently explored as a new material for functional, molecular nano-architectures. In this respect, one major question is to transform DNA into a conducting material which has the potential for self-assembly into electronically active networks. The article covers recent insight into how DNA transports positive (... |
12942628 | [The eukaryotic replication complex and its affinity modification analysis]. | Replication of eukaryotic DNA is driven by a protein complex, in which the central part is played by DNA polymerases. Synthesis with eukaryotic DNA polymerases alpha, delta, and epsilon involves various replication factors, including the replication protein A, replication factor C, proliferating cell nuclear antigen, e... |
12943229 | Polyglutamine diseases: a transcription disorder? | Various molecular processes including unfolded protein response, protein transport, synaptic transmission and transcription are implicated in the pathology of polyglutamine diseases caused by the expanded polyglutamine-containing proteins. More than 20 transcription-related factors have been reported to interact with d... |
12943227 | Polyamine-dependent gene expression. | The polyamines spermidine and spermine along with the diamine putrescine are involved in many cellular processes, including chromatin condensation, maintenance of DNA structure, RNA processing, translation and protein activation. The polyamines influence the formation of compacted chromatin and have a well-established ... |
12943226 | The hypoxia-inducible factors: key transcriptional regulators of hypoxic responses. | Oxygen depravation in mammals leads to the transcriptional induction of a host of target genes to metabolically adapt to this deficiency, including erythropoietin and vascular endothelial growth factor. This response is primarily mediated by the hypoxia-inducible factors (HIFs) which are members of the basic-helix-loop... |
12943219 | What's new in the field of cancer vaccines? | The observation that in some cases tumors undergo spontaneous regression concomitantly with autoimmune manifestations has been interpreted as an indication of the involvement of the immune system in tumor rejection. This raised the conceptual possibility that the immune system could be used against the tumor. However, ... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.