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7849585 | Influenza virus neuraminidase: structure, antibodies, and inhibitors. | The determination of the 3-dimensional structure of the influenza virus neuraminidase in 1983 has served as a platform for understanding interactions between antibodies and protein antigens, for investigating antigenic variation in influenza viruses, and for devising new inhibitors of the enzyme. That work is reviewed ... |
7841222 | Liquid chromatographic separation of zalcitabine and its stereoisomers. | A liquid chromatographic method capable of separating and quantitating the stereoisomers of zalcitabine has been developed and validated. The separation was achieved with an Astec Cyclobond I--RSP column and a mobile phase of 0.25% triethylamine in water adjusted to a pH of 6.5 with glacial acetic acid. All enantiomers... |
7841220 | Stabilization of an anthrapyrazole antitumour agent, DuP 937, on complexation with heptakis(2,6-di-O-methyl)-beta-cyclodextrin in aqueous solution. | DuP 937, an anthrapyrazole antitumour agent that is chemically unstable in aqueous solution, was shown, by absorption spectroscopy, to form an inclusion complex with heptakis(2,6-di-O-methyl)-beta-cyclodextrin (DM beta CD) in aqueous solution. Proton nuclear magnetic resonance spectroscopy was used to determine the sto... |
7840562 | Improvement of outer membrane-permeabilizing and lipopolysaccharide-binding activities of an antimicrobial cationic peptide by C-terminal modification. | Antimicrobial cationic peptides have been discovered in many different organisms and often possess a broad range of activity. In this study, we investigated the mechanisms of actions of melittin and two synthetic peptides, CEME (a cecropin-melittin hybrid) and CEMA, against gram-negative bacteria. CEMA was produced by ... |
7530766 | Lysophospholipids modulate channel function by altering the mechanical properties of lipid bilayers. | Lipid metabolites, free fatty acids and lysophospholipids, modify the function of membrane proteins including ion channels. Such alterations can occur through signal transduction pathways, but may also result from "direct" effects of the metabolite on the protein. To investigate possible mechanisms for such direct effe... |
7829575 | Self-assembling biomolecular materials in medicine. | Materials that mimic or extend the properties of natural molecules are being developed for medical applications. Recent breakthroughs in genetic engineering, polymer synthesis, molecular self-assembly and related areas are greatly expanding the variety of structures available for use in physiological settings. |
7819490 | Contribution of electrogenic ion transport to impedance of the algae Valonia utricularis and artificial membranes. | The cell membrane of Valonia utricularis contains an electrogenic carrier system for chloride (Wang et al., Biophys J. 59:235-248 (1991)). The electrical impedance of V. utricularis was measured in the frequency range between 1 Hz and 50 kHz. The analysis of the impedance spectra from V. utricularis and its comparison ... |
7819480 | A liquid crystalline phase in spermidine-condensed DNA. | Over a large range of salt and spermidine concentrations, short DNA fragments precipitated by spermidine (a polyamine) sediment in a pellet from a dilute isotropic supernatant. We report here that the DNA-condensed phase consists of a cholesteric liquid crystal in equilibrium with a more concentrated phase. These resul... |
7815707 | [Hormonal changes and pituitary histological and immunocytochemical studies of patients with multiple organ failure]. | <h4>Objective</h4>We investigated the correlation between the endogenous hormonal changes of pituitary-adrenal and pituitary-thyroid hormones and the prognosis of patients in multiple organ failure, and elucidated the mechanism of blunted thyrotropin (TSH) secretion by histological and immunocytochemical studies of ant... |
7986380 | Antisense peptides to the 43-57 region of acylphosphatase and to the 46-60 region of two isoenzymes of a low-M(r) phosphotyrosine protein phosphatase do not interact with the corresponding proteins. | Three peptides complementary to exposed regions of two low-M(r) phosphotyrosine protein phosphatase isoenzymes and of the acylphosphatase muscle isoenzyme have been synthesized. Each peptide was synthesized on two different types of resins; the peptides were anchored to the resins by amide linkages. The peptide resins ... |
7986057 | Identification of a heroin esterase in Rhodococcus sp. strain H1. | A strain of a Rhodococcus sp. (termed H1) capable of utilizing heroin as its sole carbon and energy source was isolated by selective enrichment. An inducible heroin esterase was partially purified and shown to catalyze the hydrolysis of both of the acetylester groups of heroin. The enzyme displays optimum activity at p... |
7986049 | Cloning of the aapT gene and characterization of its product, alpha-amylase-pullulanase (AapT), from thermophilic and alkaliphilic Bacillus sp. strain XAL601. | A thermophilic and alkaliphilic Bacillus sp. strain, XAL601, was isolated from soil. It produces a thermostable and alkaline-stable enzyme with both alpha-amylase and pullulanase activities. The alpha-amylase-pullulanase gene (aapT) from this Bacillus strain was cloned, and its nucleotide sequence was determined (GenBa... |
7526937 | Mixed polymer networks in the direct analysis of pharmaceuticals in urine by capillary electrophoresis. | Two-component polymer mixtures of polyethylene oxide-polydextran have been investigated as unique separation media for capillary electrophoresis. The effects of concentration of the individual polymers and their mixtures on the electroosmotic velocity and electrophoretic mobility of small pharmaceutical compounds were ... |
7981835 | Determination of pharmaceuticals and related impurities by capillary electrophoresis. | In the first part of this work, the use of capillary electrophoresis (CE) for the separation of two groups of pharmaceuticals, namely a metabolite of tamoxifen and a basic drug substance, DS1 was investigated. The effects of pH and types of modifiers, e.g. surfactant, bile salt, gamma-cyclodextrin and hydroxypropyl-bet... |
7981834 | Determination of synthetic food dyes by capillary electrophoresis. | A method for the determination of synthetic tar dyes used as food additives using capillary electrophoresis with photodiode-array detection was investigated. The dyes Erythrosine (R-3), Phloxine (R-104), Rose Bengal (R-105), Acid Red (R-106), Amaranth (R-2), New Coccine (R-102) and Allura Red AC (R-40) were separated o... |
7978313 | Kinetic method for the quantitative resolution of structural isomers based on the catalytic properties of beta-cyclodextrin. | This paper describes a new approach for the quantitative resolution of mixtures of structural isomers. The method is based on the observation that rate constants for the cyclodextrin-catalyzed hydrolysis of selected structural isomers are significantly different. By using cure-fitting methods, it is possible to use the... |
7965710 | The estrus cycle, sensitivity to convulsants and the anticonvulsant effect of a neuroactive steroid. | Recent in vitro work in our laboratory suggests that functional sensitivity of the gamma-aminobutyric acidA receptor complex to the neuroactive progesterone metabolite 3 alpha-hydroxy-5 alpha-pregnan-20-one (3 alpha,5 alpha-P) changes during the estrus cycle. Therefore, the current in vivo studies were conducted to eva... |
7961147 | Membrane skeleton in fresh unfixed erythrocytes as revealed by a rapid-freezing and deep-etching method. | A rapid-freezing and deep-etching method for examining en face the cytoplasmic aspects of unfixed erythrocyte membranes is described, which provides improved resolution. Normal human erythrocytes were centrifuged, washed in a phosphate buffer solution and pelleted. Glass coverslips were coated with 3-aminopropyl trieth... |
7957065 | Human DNA helicase II: a novel DNA unwinding enzyme identified as the Ku autoantigen. | Human DNA helicase II (HDH II) is a novel ATP-dependent DNA unwinding enzyme, purified to apparent homogeneity from HeLa cells, which (i) unwinds exclusively DNA duplexes, (ii) prefers partially unwound substrates and (iii) proceeds in the 3' to 5' direction on the bound strand. HDH II is a heterodimer of 72 and 87 kDa... |
7525004 | Enantioselective degradation of alpha-hexachlorocyclohexane and cyclodiene insecticides in roe-deer liver samples from different regions of Germany. | Remarkably high concentrations of alpha-hexachlorocyclohexane (alpha-HCH), cis-heptachlorepoxide and oxychlordane were found in roe-deer liver samples both from the northern and southern German states Schleswig-Holstein and Baden-Württemberg, respectively. The data revealed no significant regional differences, but they... |
7948720 | Detection of monodisperse aggregates of a recombinant amelogenin by dynamic light scattering. | Recombinant murine amelogenins M179 and M166 were expressed in Escherichia coli and purified. The aggregation properties of these amelogenins have been investigated in aqueous solutions as well as acetonitrile-containing solutions using dynamic light scattering. Dynamic light scattering provides direct measurement of t... |
7524560 | Identification of acetylcholine receptor channel-lining residues in the entire M2 segment of the alpha subunit. | Each residue in and flanking the M2 membrane-spanning segment of the alpha subunit, from Glu-241 to Glu-262, was mutated to cysteine, and the mutant subunits were expressed together with wild-type beta, gamma, and delta subunits in Xenopus oocytes. Cysteines substituted for Glu-262, Leu-258, Val-255, Ser-252, Leu-251, ... |
7943170 | The gamma 2 chain of kalinin/laminin 5 is preferentially expressed in invading malignant cells in human cancers. | All known laminin isoforms are cross-shaped heterotrimeric molecules, consisting of one heavy alpha chain and two light beta and gamma chains. Recently, a cDNA encoding a new gamma chain from laminin 5 (also known as kalinin) was sequenced. This chain, named gamma 2, showed extended homology to the classical gamma 1 ch... |
7840821 | Idiotypic mimicry and the assembly of a supramolecular structure: an anti-idiotypic antibody that mimics taxol in its tubulin-microtubule interactions. | Taxol, originally extracted from the bark of the western yew, Taxus brevifolia, is reportedly the first of a new class of anti-cancer agents. It acts by promoting and irreversibly stabilizing microtubule assembly, thus interfering with the dynamic processes required for cell viability and multiplication. With the aim o... |
7524095 | Heme coordination of NO in NO synthase. | A current question in nitric oxide (NO) biology is whether NO can act as a feedback inhibitor of NO synthase (NOS). We have approached this problem by examining the interaction of NO with neuronal NOS by optical absorption and resonance Raman scattering spectroscopies. Under an inert atmosphere NO coordinated to the he... |
7937955 | A cysteine residue in the third membrane-spanning segment of the human D2 dopamine receptor is exposed in the binding-site crevice. | The binding site in G-protein-linked neurotransmitter receptors is formed among their membrane-spanning segments. Because the binding site is in the plane of the bilayer and is accessible to charged, water-soluble agonists, it must lie in a crevice open to the extracellular, aqueous medium. Information about the struct... |
7937891 | Imaging nuclear pores of aldosterone-sensitive kidney cells by atomic force microscopy. | In nuclei of renal target cells, aldosterone enhances transcriptional activity followed by the translocation of specific RNA molecules across the nuclear envelope. Trafficking between cell nucleus and cytoplasm occurs via nuclear pore complexes (NPCs) located in the double-layered nuclear envelope. We investigated the ... |
7937879 | Cellular vacuoles induced by Helicobacter pylori originate from late endosomal compartments. | Pathogenic strains of Helicobacter pylori cause progressive vacuolation and death of epithelial cells. To identify the nature of vacuoles, the distribution of markers of various membrane traffic compartments was studied. Vacuoles derive from the endocytic pathway since they include the fluid-phase marker Lucifer yellow... |
7937844 | The murine mutation jaundiced is caused by replacement of an arginine with a stop codon in the mRNA encoding the ninth repeat of beta-spectrin. | The jaundiced, ja/ja, mouse mutant has a severe hemolytic anemia associated with a deficiency of beta-spectrin in erythrocyte ghosts. Genes for the disease phenotype and beta-spectrin colocalize on Chromosome 12. beta-Spectrin mRNA is not detected in reticulocytes or in brain from newborn mutant mice. To locate the nuc... |
7937830 | Modulation by gangliosides of the lamellar-inverted micelle (hexagonal II) phase transition in mixtures containing phosphatidylethanolamine and dioleoylglycerol. | We studied the effect of gangliosides GD1a and GM1 on the lamellar-to-hexagonal II phase transition of mixtures of dioleoylphosphatidylethanolamine/dioleoylphosphatidyl choline, 3:1, and of transphosphatidylated phosphatidylethanolamine with dioleoylglycerol by high-sensitivity differential scanning calorimetry, 31P-NM... |
7937147 | Cooperative binding of initiator protein to replication origin conferred by single amino acid substitution. | The replication initiator protein pi of plasmid R6K binds seven 22 bp direct repeats (DR) in the gamma origin. The pi protein also binds to an inverted repeat (IR) in the operator of its own gene, pir, which lies outside the gamma origin sequences. A genetic system was devised to select for pi protein mutants which dis... |
7523953 | Crystal structure of an RNA bacteriophage coat protein-operator complex. | The RNA bacteriophage MS2 is a convenient model system for the study of protein-RNA interactions. The MS2 coat protein achieves control of two distinct processes--sequence-specific RNA encapsidation and repression of replicase translation--by binding to an RNA stem-loop structure of 19 nucleotides containing the initia... |
7935377 | NF-IL6 and AP-1 cooperatively modulate the activation of the TSG-6 gene by tumor necrosis factor alpha and interleukin-1. | Tumor necrosis factor alpha (TNF-alpha) and interleukin-1 (IL-1) activate transcription of the TSG-6 gene in normal human fibroblasts through a promoter region (-165 to -58) that encompasses an AP-1 and a NF-IL6 site. We show by deletion analysis and substitution mutagenesis that both sites are necessary for activation... |
7935371 | The RNA polymerase I transactivator upstream binding factor requires its dimerization domain and high-mobility-group (HMG) box 1 to bend, wrap, and positively supercoil enhancer DNA. | Upstream binding factor (UBF) is an important transactivator of RNA polymerase I and is a member of a family of proteins that contain nucleic acid binding domains named high-mobility-group (HMG) boxes because of their similarity to HMG chromosomal proteins. UBF is a highly sequence-tolerant DNA-binding protein for whic... |
7932900 | A prospective comparison of two multiple organ dysfunction/failure scoring systems for prediction of mortality in critical surgical illness. | Multiple organ failure (MOF) is the primary cause of death in surgical intensive care units (SICU). Mortality increases with an increasing number of failed organs, but it has been recognized that lesser degrees of organ dysfunction occur commonly. Such gradations of the multiple organ dysfunction syndrome (MODS) are po... |
7932742 | The motile major sperm protein (MSP) of Ascaris suum forms filaments constructed from two helical subfilaments. | The amoeboid motility nematode sperm is mediated by cytoskeletal filaments composed of major sperm protein (MSP). We have used electron microscopy and image processing to show that MSP filaments are constructed from two subfilament strands which are themselves formed from a helical arrangement of subunits. The subfilam... |
7932588 | 2-Substitution of N6-benzyladenosine-5'-uronamides enhances selectivity for A3 adenosine receptors. | Adenosine derivatives bearing an N6-(3-iodobenzyl) group, reported to enhance the affinity of adenosine-5'-uronamide analogues as agonists at A3 adenosine receptors (J. Med. Chem. 1994, 37, 636-646), were synthesized starting from methyl beta-D-ribofuranoside in 10 steps. Binding affinities at A1 and A2a receptors in r... |
7931059 | Bordetella pertussis filamentous hemagglutinin interacts with a leukocyte signal transduction complex and stimulates bacterial adherence to monocyte CR3 (CD11b/CD18). | Bordetella pertussis, the causative agent of whooping cough, adheres to human monocytes/macrophages by means of a bacterial surface-associated protein, filamentous hemagglutinin (FHA) and the leukocyte integrin, complement receptor 3 (CR3, alpha M beta 2, CD11b/CD18). We show that an FHA Arg-Gly-Asp site induces enhanc... |
7930843 | Mobilization of radioactive strontium from mouse and rat using dicarboxylic acid derivatives of cryptand (2.2). | To date, there has been no effective therapy to counter incorporated radionuclides of strontium. In an endeavour to solve this problem, we have synthesized and evaluated various N,N'-disubstituted derivatives of 1,4,10,13-tetraoxa-7,16-diaza-cyclooctadecane(crypt and 2.2) for their ability to mobilize 85Sr2+. These lig... |
7929841 | Amino acid substitutions in the hormone-binding domain of the human androgen receptor alter the stability of the hormone receptor complex. | We have investigated the basis of androgen resistance in seven unrelated individuals with complete testicular feminization or Reifenstein syndrome caused by single amino acid substitutions in the hormone-binding domain of the androgen receptor. Monolayer-binding assays of cultured genital skin fibroblasts demonstrated ... |
7929418 | Molecular recognition at the myo-inositol 1,4,5-trisphosphate receptor. 3-position substituted myo-inositol 1,4,5-trisphosphate analogues reveal the binding and Ca2+ release requirements for high affinity interaction with the myo-inositol 1,4,5-trisphosphate receptor. | Several novel D-myo-inositol 1,4,5-trisphosphate (Ins(1,4,5)P3] analogues equatorially substituted at the 3-position have been synthesized to probe the structure-activity relationship of the Ins(1,4,5)P3-receptor subsite adjacent to the native 3-hydroxy (3-OH) of Ins(1,4,5)P3. This study was prompted, in part, by our o... |
7929196 | LIM domain recognition of a tyrosine-containing tight turn. | Endocytosis of cell surface receptors requires sequence "codes" consisting of tight turn structures with an essential Tyr or Phe residue. To determine mechanisms through which cells recognize this information, we utilized exon 16 of the human insulin receptor in the two-hybrid system to isolate a novel 455-amino acid c... |
7929003 | Characterization of mutants of Caulobacter crescentus defective in surface attachment of the paracrystalline surface layer. | Strains of Caulobacter crescentus express a paracrystalline surface layer (S-layer) consisting of the protein RsaA. Mutants of C. crescentus NA1000 and CB2, isolated for their ability to grow in the absence of calcium ions, uniformly no longer had the S-layer attached to the cell surface. However, RsaA was still produc... |
7928972 | Relationship between ftsZ gene expression and chromosome replication in Escherichia coli. | Transcriptional levels within the ftsQAZ region of the Escherichia coli chromosome were correlated with chromosome replication and the division cycle. The transcripts were measured either in synchronous cultures generated by the baby machine technique or in dnaC2(Ts) mutants that had been aligned for initiation of chro... |
7928970 | Characterization of lipoprotein EnvA in Chlamydia psittaci 6BC. | The primary sequence of the small cysteine-rich protein (EnvA) of Chlamydia psittaci 6BC has been shown to possess a potential lipid modification/signal peptidase II-processing site, and the mature protein was labeled by a [3H]palmitic acid precursor. We further characterized the mature EnvA, showing that it lacks the ... |
7927702 | Epithelial glucosphingolipid expression as a determinant of bacterial adherence and cytokine production. | D-Threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP) is a structural analog of ceramide that inhibits glucosylation of this molecule and thus of glucosphingolipid (GSL) expression by living cells. In this study, we used PDMP to slow the synthesis of the globoseries of GSLs (globo-GSLs) (derived from the prec... |
7927683 | Surface-associated filamentous hemagglutinin induces autoagglutination of Bordetella pertussis. | Filamentous hemagglutinin (FHA) is a major adhesin produced by Bordetella pertussis, the etiologic agent of whooping cough. FHA has been shown to be surface associated but is also secreted by virulent bacteria. Microscopic observations of lungs of mice infected with B. pertussis showed that the bacteria grow as cluster... |
7926034 | Parallel beta/alpha-barrels of alpha-amylase, cyclodextrin glycosyltransferase and oligo-1,6-glucosidase versus the barrel of beta-amylase: evolutionary distance is a reflection of unrelated sequences. | The structures of functionally related beta/alpha-barrel starch hydrolases, alpha-amylase, beta-amylase, cyclodextrin glycosyltransferase and oligo-1,6-glucosidase, are discussed, their mutual sequence similarities being emphasized. Since these enzymes (except for beta-amylase) along with the predicted set of more than... |
7925430 | Thermodynamics of ligand binding to the starch-binding domain of glucoamylase from Aspergillus niger. | The thermodynamics of ligand binding to the starch-binding domain (SBD) of glucoamylase from Aspergillus niger has been studied using titration calorimetry. The ligand binding was studied both with the SBD fragment as well as glucoamylase G1 which contains both a catalytic domain and SBD. The ligands were beta-cyclodex... |
7522644 | Prevention of graft-versus-host disease by peptides binding to class II major histocompatibility complex molecules. | Graft-versus-host disease across minor histocompatibility barriers was induced in two different models by transplanting allogeneic bone marrow and spleen cells into irradiated H-2-compatible recipient mice. In this report, we show that administration of peptides with high binding affinity for the respective class II ma... |
7918558 | Self-assembly of mastoparan X derivative having fluorescence probe in lipid bilayer membrane. | A mastoparan X (MPX) derivative having an anthryl group at the C-terminal residue was synthesized (MPX-A), and its conformation, orientation and aggregation in phospholipid bilayer membrane were studied. The efficiency of intramolecular energy transfer from the Trp residue to the anthryl group at high peptide dilution ... |
8084017 | Recombinant rabbit hemorrhagic disease virus capsid protein expressed in baculovirus self-assembles into viruslike particles and induces protection. | VP60, the unique component of rabbit hemorrhagic disease virus capsid, was expressed in the baculovirus system. The recombinant VP60, released in the supernatant of infected insect cells, assembled without the need of any other viral component to form viruslike particles (VLPs), structurally and immunologically indisti... |
8083993 | The human cytomegalovirus origin of DNA replication (oriLyt) is the critical cis-acting sequence regulating replication-dependent late induction of the viral 1.2-kilobase RNA promoter. | Plasmid constructs containing the 1.2-kb RNA promoter from the long terminal repeat region of human cytomegalovirus (HCMV) display the early-phase regulation of this promoter but lack the characteristic late induction (E. J. Wade, K. M. Klucher, and D. H. Spector, J. Virol. 66:2407-2417, 1992). To determine if the HCMV... |
17771445 | Simulating the self-assembly of gemini (dimeric) surfactants. | The morphologies and dynamics of aggregates formed by surfactant molecules are known to influence strongly performance properties spanning biology, household cleaning, and soil cleanup. Molecular dynamics simulations were used to investigate the morphology and dynamics of a class of surfactants, the gemini or dimeric s... |
16349420 | Binding of Insecticidal Crystal Proteins of Bacillus thuringiensis to the Midgut Brush Border of the Cabbage Looper, Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae), and Selection for Resistance to One of the Crystal Proteins. | The susceptibility of Trichoplusia ni larvae to several Bacillus thuringiensis insecticidal crystal proteins (ICPs) was tested. Neonatal larvae proved to be susceptible to solubilized trypsin-treated CryIA(a), CryIA(b), and CryIA(c) (50% lethal concentrations [LC(50)s], 570, 480, and 320 ng/cm, respectively) but showed... |
16349415 | Production, Purification, and Properties of a Thermostable beta-Glucosidase from a Color Variant Strain of Aureobasidium pullulans. | A color variant strain of Aureobasidium pullulans (NRRL Y-12974) produced beta-glucosidase activity when grown in liquid culture on a variety of carbon sources, such as cellobiose, xylose, arabinose, lactose, sucrose, maltose, glucose, xylitol, xylan, cellulose, starch, and pullulan. An extracellular beta-glucosidase w... |
16349414 | Production of 10-Ketostearic Acid from Oleic Acid by Flavobacterium sp. Strain DS5 (NRRL B-14859). | A microbial isolate, Flavobacterium sp. strain DS5, produces 10-ketostearic acid (10-KSA) from oleic acid in 85% yield. This is the first report on this type of reaction catalyzed by a Flavobacterium strain. The product was purified to give white, plate-like crystals melting at 79.2 degrees C. The optimum time, pH, and... |
9644191 | Transgenic approaches for modifying the mammary gland to produce therapeutic proteins. | Bioengineering of the mammary gland to produce proteins of therapeutic and industrial value is the result of extensive investigation of the physiology of the mammary gland and the ability to generate transgenic animals. Targeting the expression of heterologous proteins to mammary tissue requires a thorough understandin... |
7757522 | Involvement of liver in the decompensation of hemorrhagic shock. | In a hemorrhagic shock model without adequate volume resuscitation we investigated the question whether a biochemical stabilization of liver function by applying 2-mercaptopropionyl-glycine (2MPG) may influence the shock dynamics especially the transition from compensated to decompensated shock and the development of m... |
7898472 | Enzymology of ADP-ribose polymer synthesis. | In this minireview, we summarize recent advances on the enzymology of ADP-ribose polymer synthesis. First, a short discussion of the primary structure and cloning of poly(ADP-ribose) polymerase (PARP) [EC 2.4.2.30], the enzyme that catalyzes the synthesis of poly(ADP-ribose), is presented. A catalytic distinction betwe... |
7880549 | Long-range interactions between DNA-bound ligands. | We have studied the interaction of the A:T specific minor-groove binding ligand 4',6-diamidino-2-phenylindole (DAPI) with synthetic DNA oligomers containing specific binding sites in order to investigate possible long-range interactions between bound ligands. We find that DAPI binds cooperatively to the oligomers. The ... |
7880548 | Conformational properties of topoisomerase II inhibitors and sequence specificity of DNA cleavage. | The sequence specificity of topoisomerase-II-mediated DNA cleavage, stimulated by 2-methyl-9-hydroxy ellipticinium and 4',5,7-trihydroxyflavone (genistein) was investigated by sequencing analysis of DNA cleavage sites and molecular modeling techniques. The former drug exhibits a marked preference for a T base at the po... |
7880547 | The cofactor ATP in DNA-RecA complexes is not intercalated between DNA bases. | In an attempt to understand the role of ATP as a cofactor at the interaction of the RecA protein with DNA, we have studied the orientation geometries of the cofactor analogs adenosine 5'-O-(3-thiotriphosphate) (ATP gamma S) and guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) in RecA-DNA complexes using flow linear di... |
7880546 | Synthetic alpha-helical peptides incorporating intercalators for DNA recognition. | The design and synthesis of a water-soluble 14-residue peptide, in which a quinoline intercalator is attached to the peptide backbone via alkylation of a central cysteine residue, is reported. 600 MHz 1H NMR spectroscopy and circular dichroism indicate that the peptide forms a nascent helix in aqueous solution, ie. an ... |
7533506 | Identification of a pharmacophore for nucleoside analog inhibitors directed at HIV-1 reverse transcriptase. | An 'active analog' approach to receptor mapping was used to identify a pharmacophore for a set of thymidine nucleoside analog inhibitors of HIV-1 reverse transcriptase. The preliminary results indicate that the O2, O4', and O5' atoms are capable of adopting a unique pharmacophoric pattern which may be the key to their ... |
7880545 | Identification and analysis of a template-primer (ds-DNA) binding cleft in E. coli DNA polymerase I: an electrostatic potential contour pattern of the modeled structure. | In the modeled structure of the Klenow fragment of E. coli DNA polymerase I, we have identified a distinct region that exhibits a strong electropositive potential contour. The examination of the distribution of the electropositive and negative potential across the two-dimensional slices of the modeled structure reveale... |
7880544 | Properties of RecA-oligonucleotide complexes. | The interaction of RecA protein with short single-stranded oligonucleotides is characterised by flow linear dichroism (LD), isoelectric focusing (IEF) and electron microscopy (EM). From LD and EM it is evident that RecA forms long filaments with at least some 50 oligonucleotides in a 'train formation'. The tendency to ... |
7880543 | Interaction of mithramycin with isolated GC and CG sites. | We have studied the interaction of the GC-specific, minor groove-binding ligand, mithramycin, with cloned DNA inserts containing isolated GC and CG sites flanked by regions of (AT)n and An.Tn using DNase I and hydroxyl radical footprinting. We find that mithramycin binds to GC better than CG and that AGCT is a better s... |
7880542 | Ethidium and azidoethidium oligonucleotide derivatives: synthesis, complementary complex formation and sequence-specific photomodification of the single-stranded and double-stranded target oligo- and polynucleotides. | Oligodeoxyribonucleotide derivatives containing ethidium or azidoethidium residues attached to 3' and/or 5' end were prepared. These derivatives formed tight specific complexes with complementary oligodeoxyribonucleotides where each attached ethidium residue led to an increase of complex Tm by 20-30 degrees C. Tandem c... |
7880541 | Electron microscopic studies of sequence-specific recognition of duplex DNA by different ligands. | The following ligands were used to study sequence specific recognition of duplex DNA by electron microscopic techniques: methyltransferases BspR1 and EcoR124 (recognition sequences GGCC and GAAN7RTCG, respectively), a biotinylated deoxyoligonucleotide 5'-CTCTCTCTCTCTCT-3' capable of forming triplex DNA, and PNA oligome... |
7880540 | Evidence for (PNA)2/DNA triplex structure upon binding of PNA to dsDNA by strand displacement. | The binding of PNA (peptide nucleic acid) T2CT2CT4-LysNH2 to the double-stranded DNA target 5'-A2GA2GA4 was studied by KMnO4 and dimethylsulfate (DMS) probing. It is found that upon sequence-specific strand displacement binding of the PNA to the dsDNA target concomitant protection of the N-7 of guanines within the targ... |
7857365 | Elastase enhances cAMP accumulation and the inhibition of DNA synthesis induced by OP-41483, a stable prostacyclin analogue, in vascular smooth muscle cells. | To define the physiological roles of elastase in the vascular wall, we examined whether elastase at low concentrations can modulate the proliferation of vascular smooth muscle cells (VSMC). Elastase itself at low concentrations from 1 to 50 ng/ml inhibited DNA synthesis dose-dependently in VSMC. However, phenylmethylsu... |
7852285 | Further characterization of mitochondrial outer membrane: evidence for the presence of two endogenous sialylated glycoproteins. | The distribution of sialic acid-containing glycoproteins was investigated in highly purified mitochondrial membranes using labeled Sambucus nigra agglutinin as a detection system. Two sialylated glycoproteins were shown to be true components of the mitochondrial outer membrane. Relative to monoamine oxidase activity, t... |
7837039 | Peracylated beta-cyclodextrins as novel sustained-release carriers for a water-soluble drug, molsidomine. | Peracylated beta-cyclodextrins with different alkyl chains (acetyl-octanoyl) were prepared by acylating all hydroxyl groups of beta-cyclodextrin (beta-CyD), and their physical properties were evaluated. These hydrophobic beta-CyDs decreased the release rate of molsidomine, a peripheral vasodilator, in proportion to the... |
7833810 | Anatomy of an engineered NAD-binding site. | The coenzyme specificity of Escherichia coli glutathione reductase was switched from NADP to NAD by modifying the environment of the 2'-phosphate binding site through a set of point mutations: A179G, A183G, V197E, R198M, K199F, H200D, and R204P (Scrutton NS, Berry A, Perham RN, 1990, Nature 343:38-43). In order to anal... |
7833808 | Refined structure of monomeric diphtheria toxin at 2.3 A resolution. | The structure of toxic monomeric diphtheria toxin (DT) was determined at 2.3 A resolution by molecular replacement based on the domain structures in dimeric DT and refined to an R factor of 20.7%. The model consists of 2 monomers in the asymmetric unit (1,046 amino acid residues), including 2 bound adenylyl 3'-5' uridi... |
7833807 | Refined structure of dimeric diphtheria toxin at 2.0 A resolution. | The refined structure of dimeric diphtheria toxin (DT) at 2.0 A resolution, based on 37,727 unique reflections (F > 1 sigma (F)), yields a final R factor of 19.5% with a model obeying standard geometry. The refined model consists of 523 amino acid residues, 1 molecule of the bound dinucleotide inhibitor adenylyl 3'-5' ... |
7831285 | Coiled-coil molecular recognition: directed solution assembly of receptor ectodomains. | The high affinity interleukin-2 (IL-2) receptor is composed of at least three cell surface proteins (alpha, beta and gamma subunits), each of which is independently capable of ligand binding. Physiologically, these subunits cooperate to form dimeric and trimeric complexes that efficiently capture IL-2 and transmit the ... |
7830253 | In vitro corneal permeability of diclofenac sodium in formulations containing cyclodextrins compared to the commercial product voltaren ophtha. | The influence of different cyclodextrin derivatives on the in vitro permeability of diclofenac sodium through pig cornea was investigated and compared to the commercial product Voltaren ophtha. (Hydroxypropyl)-beta-cyclodextrin (HP beta CD) and two amorphous methylated cyclodextrins with different degrees of substituti... |
7825065 | On the role of lipids in cell regulatory economy. | Prenylated proteins, which contain a lipid tail, may function to enhance the self-assembly of complementary molecular structures by providing a monomolecular film between the two combining regions so that electrostatic forces of attraction are greatly increased over that which would be established with water molecules ... |
7821362 | Adenosine A3 receptor stimulation and cerebral ischemia. | Chronic treatment with the selective adenosine A3 receptor agonist N6-(3-iodobenzyl)adenosine-5'-N-methylcarboxamide (IB-MECA) administered prior to either 10 or 20 min forebrain ischemia in gerbils resulted in improved postischemic cerebral blood circulation, survival, and neuronal preservation. Opposite effects, i.e.... |
7820282 | Fluorogenic reactions for biomedical chromatography. | A number of fluorogenic reactions, which have been used for HPLC detection systems by means of pre- and/or postcolumn derivatization, are surveyed with respect to both sensitivity and selectivity for the determination of biomedically important substances. For the derivatization of the substances, two types of fluorogen... |
7820281 | Enantiomeric derivatization for biomedical chromatography. | Derivatization reactions aimed at creating the basis for the chromatographic resolution of biologically and pharmaceutically important enantiomers are reviewed, with emphasis on the literature published in the last 10 years. Three main aspects of chiral derivatization are discussed. (a) Enantiomers containing suitable ... |
7814663 | Expression of the neural cell adhesion molecule (NCAM) and polysialic acid during taste bud degeneration and regeneration. | Taste receptor cells are replaced throughout life, accompanied by continuing synaptogenesis between newly formed taste cells and first-order gustatory fibers. The neural cell adhesion molecule (NCAM) is expressed by a subset of taste cells in adult rodents and appears on gustatory nerve fibers during development prior ... |
7811955 | Mean-field calculations of chain packing and conformational statistics in lipid bilayers: comparison with experiments and molecular dynamics studies. | A molecular, mean-field theory of chain packing statistics in aggregates of amphiphilic molecules is applied to calculate the conformational properties of the lipid chains comprising the hydrophobic cores of dipalmitoyl-phosphatidylcholine (DPPC), dioleoyl-phosphatidylcholine (DOPC), and palmitoyl-oleoyl-phosphatidylch... |
7811946 | Influence of surface and protein modification on immunoglobulin G adsorption observed by scanning force microscopy. | Scanning force microscopy has been used successfully to produce images of individual protein molecules. However, one of the problems with this approach has been the high mobility of the proteins caused by the interaction between the sample and the scanning tip. To stabilize the proteins we have modified the adsorption ... |
7811939 | Recognition and processing of randomly fluctuating electric signals by Na,K-ATPase. | Previous work has shown that Na,K-ATPase of human erythrocytes can extract free energy from sinusoidal electric fields to pump cations up their respective concentration gradients. Because regularly oscillating waveform is not a feature of the transmembrane electric potential of cells, questions have been raised whether... |
7811938 | Effect of acid predissolution on fibril size and fibril flexibility of synthetic beta-amyloid peptide. | beta-amyloid peptide (A beta) is the major protein component of senile plaques and cerebrovascular amyloid deposits in Alzheimer's patients. Several researchers have demonstrated that A beta is neurotoxic in in vitro and in vivo systems. Peptide aggregation state and/or conformation might play a significant role in det... |
7811937 | Biologically addressable monolayer structures formed by templates of sulfur-bearing molecules. | We demonstrate that the combined application of Langmuir-Blodgett and self-assembly techniques allows the fabrication of patterns with contrasting surface properties on gold substrates. The process is monitored using fluorescence microscopy and surface plasmon spectroscopy and microscopy. These structures are suitable ... |
7811936 | Amyloid-beta aggregation: selective inhibition of aggregation in mixtures of amyloid with different chain lengths. | One of the clinical manifestations of Alzheimer's disease is the deposition of the 39-43 residue amyloid-beta (A beta) peptide in aggregated fibrils in senile plaques. Characterization of the aggregation behavior of A beta is one of the critical issues in understanding the role of A beta in the disease process. Using s... |
7811920 | Membrane solubilization by a hydrophobic polyelectrolyte: surface activity and membrane binding. | We have previously observed that the hydrophobic polyelectrolyte poly(2-ethylacrylic acid) solubilizes lipid membranes in a pH-dependent manner, and we have exploited this phenomenon to prepare lipid vesicles that release their contents in response to pH, light, or glucose (Thomas, J. L., and D. A. Tirrell. Acc. Chem. ... |
7811911 | The saxitoxin/tetrodotoxin binding site on cloned rat brain IIa Na channels is in the transmembrane electric field. | The rat brain IIa (BrIIa) Na channel alpha-subunit and the brain beta 1 subunit were coexpressed in Xenopus oocytes, and peak whole-oocyte Na current (INa) was measured at a test potential of -10 mV. Hyperpolarization of the holding potential resulted in an increased affinity of STX and TTX rested-state block of BrIIa ... |
7810996 | Contribution of VanY D,D-carboxypeptidase to glycopeptide resistance in Enterococcus faecalis by hydrolysis of peptidoglycan precursors. | The vanR, vanS, vanH, vanA, and vanX genes of enterococcal transposon Tn1546 were introduced into the chromosome of Enterococcus faecalis JH2-2. Complementation of this portion of the van gene cluster by a plasmid encoding VanY D,D-carboxypeptidase led to a fourfold increase in the vancomycin MIC (from 16 to 64 microgr... |
7810995 | Selective inhibition of topoisomerases from Pneumocystis carinii compared with that of topoisomerases from mammalian cells. | Type I and II topoisomerase activities were partially purified from Pneumocystis carinii. The catalytic (strand-passing) activities of both enzymes were selectively inhibited by members of a series of dicationic-substituted bis-benzimidazoles compared with those of topoisomerases of mammalian (calf thymus) origin. The ... |
7798375 | Distribution of histamine-, 5-hydroxytryptamine-, and tyrosine hydroxylase-immunoreactive neurons and nerve fibers in developing rat brain. | Although the general patterns of the developing histaminergic system in the rat brain are known, no comparative studies between the development of the brain histaminergic system and the development of other neuroactive substances have yet been published. Interestingly, separate immunohistochemical studies on the develo... |
8001181 | Lipid dynamics and peripheral interactions of proteins with membrane surfaces. | A large body of evidence strongly indicates biomembranes to be organized into compositionally and functionally specialized domains, supramolecular assemblies, existing on different time and length scales. For these domains and intimate coupling between their chemical composition, physical state, organization, and funct... |
7996518 | Trophism, tropism, and specificity in nerve regeneration. | Target-derived neurotrophic factors are of basic importance for survival of neurons. In the normal state, such neurotrophic factors, synthesized by the target tissues, are taken up by nerve terminals and transported by retrograde axonal transport in axons to the nerve-cell bodies to maintain their viability. After nerv... |
7765619 | Polyphenols, astringency and proline-rich proteins. | Recent, NMR and precipitation, studies of molecular recognition of proline-rich proteins and peptides by plant polyphenols are described and rationalized. The action of polysaccharides and caseins in the moderation of the astringent response, which is engendered by polyphenols present in foodstuffs and beverages, is de... |
7982219 | Selective pivaloylation and diphenylacetylation of cyclomalto-oligosaccharides. | Regioselective acylation of cyclomalto-oligosaccharides was achieved using pivaloyl and diphenylacetyl chlorides. The reaction of cyclomaltohexaose (1) with pivaloyl chloride gave the hexakis(2,6-di-O-pivaloyl) derivative 19 in 66% yield. Similar reaction with cyclomalto-heptaose (2) led to the octakis(2I,6I,6II,6III,6... |
7981946 | Efficient preparation of plant chromosomes for high-resolution scanning electron microscopy. | A highly reproducible technique to prepare plant chromosomes for high-resolution field emission scanning electron microscopy is presented. The procedure allows the production of relatively high numbers of chromosome spreads that can be viewed at high resolution, showing structural details below 10 nm. This preparation ... |
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