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9343250 | Replication-competent picornaviruses with complete genomic RNA 3' noncoding region deletions. | The genomic RNA 3' noncoding region is believed to be a major cis-acting molecular genetic determinant for regulating picornavirus negative-strand RNA synthesis by promoting replication complex recognition. We report the replication of two picornavirus RNAs harboring complete deletions of the genomic RNA 3' noncoding r... |
9343236 | Dimerization of simian virus 40 T-antigen hexamers activates T-antigen DNA helicase activity. | Chromosomal DNA replication in higher eukaryotes takes place in DNA synthesis factories containing numerous replication forks. We explored the role of replication fork aggregation in vitro, using as a model the simian virus 40 (SV40) large tumor antigen (T antigen), essential for its DNA helicase and origin-binding act... |
9343229 | Rotavirus virus-like particles administered mucosally induce protective immunity. | We have evaluated the immunogenicity and protective efficacy of rotavirus subunit vaccines administered by mucosal routes. Virus-like particles (VLPs) produced by self-assembly of individual rotavirus structural proteins coexpressed by baculovirus recombinants in insect cells were the subunit vaccine tested. We first c... |
9343198 | Biochemical properties of hepatitis C virus NS5B RNA-dependent RNA polymerase and identification of amino acid sequence motifs essential for enzymatic activity. | The NS5B protein of the hepatitis C virus (HCV) is an RNA-dependent RNA polymerase (RdRp) (S.-E. Behrens, L. Tomei, and R. De Francesco, EMBO J. 15:12-22, 1996) that is assumed to be required for replication of the viral genome. To further study the biochemical and structural properties of this enzyme, an NS5B-hexahist... |
9343193 | Regulation of receptor binding affinity of influenza virus hemagglutinin by its carbohydrate moiety. | The hemagglutinin (HA) of the fowl plague virus (FPV) strain of influenza A virus has two N-linked oligosaccharides attached to Asn123 and Asn149 in the vicinity of the receptor binding site. The effect of these carbohydrate side chains on the binding of HA to neuraminic acid-containing receptors has been analyzed. Whe... |
9343190 | Arginine-glycine-aspartic acid-specific binding by foot-and-mouth disease viruses to the purified integrin alpha(v)beta3 in vitro. | The integrin alpha(v)beta3 has been shown to act as the receptor for internalization of foot-and-mouth disease virus (FMDV) (A12), with attachment being through a highly conserved RGD motif located on the G-H loop of viral capsid protein VP1. In addition, however, we have recently shown that efficient infection of cult... |
9343159 | Identification of envelope protein residues required for the expanded host range of 10A1 murine leukemia virus. | The 10A1 murine leukemia virus (MuLV) is a recombinant type C retrovirus isolated from a mouse infected with amphotropic MuLV (A-MuLV). 10A1 and A-MuLV have 91% amino acid identity in their envelope proteins yet display different host ranges. For example, CHO-K1 cells are resistant to A-MuLV but susceptible to infectio... |
9336453 | Asymmetry in Flp-mediated cleavage. | Flp is a member of the integrase family of site-specific recombinases. Members of the integrase family mediate DNA strand cleavage via a transesterification reaction involving an active site tyrosine residue. The first step of the reaction results in covalent linkage of the protein to the 3'-phosphoryl DNA terminus, le... |
9334413 | Developmental synaptic depression underlying reorganization of visceral reflex pathways in the spinal cord. | During development, neuronal connectivity has a remarkable plasticity. Synaptic refinement in the spinal autonomic nucleus might be involved in the elimination of primitive segmental reflexes and the emergence of mature spinobulbospinal reflexes, which occurs a few weeks after birth. To address this possibility, we exa... |
9334400 | Association and colocalization of the Kvbeta1 and Kvbeta2 beta-subunits with Kv1 alpha-subunits in mammalian brain K+ channel complexes. | The differential expression and association of cytoplasmic beta-subunits with pore-forming alpha-subunits may contribute significantly to the complexity and heterogeneity of voltage-gated K+ channels in excitable cells. Here we examined the association and colocalization of two mammalian beta-subunits, Kvbeta1 and Kvbe... |
10423637 | Prostaglandin E1 : electrophysiological safety in patients with congestive heart failure and peripheral arterial occlusive disease. The Alprostadil Investigators. | Prostaglandin E ( 1 ) (PGE ( 1 ) ), the active ingredient of the drug alprostadil-alpha-cyclodextrin, has been effective in mitigating the clinical manifestations of peripheral arterial occlusive disease (PAOD). PGE ( 1 ) often is administered to patients with the potential for developing serious arrhythmias, presentin... |
9867995 | [Experimental study on the collateral sprouting after end-to-side anastomosis of nerve trunk]. | In order to observe the collateral sprouting capacity of the nerve trunk after end-to-side anastomosis, a window was made on the epineurim of the donor nerve through which the result of the end-to-end anastomosis of nerves could be compared. Sixteen SD rats were chosen and divided into 4 groups randomly. Group 1, the p... |
9827418 | Separation of cis-/trans-diastereomers and enantiomers of aminoindanol and aminoindan using capillary electrophoresis. | Aminoindanol poses an interesting separation problem because it contains two chiral centers and exists as four stereoisomers. The capillary electrophoretic separation of the cis- and the larger trans-diastereomers of aminoindanol is simply achieved by pH control of the tris buffer background electrolyte. In accordance ... |
9770652 | Molecular docking of superantigens with class II major histocompatibility complex proteins. | The molecular recognition of two superantigens with class II major histocompatibility complex molecules was simulated by using protein-protein docking. Superantigens studied were staphylococcal enterotoxin B (SEB) and toxic shock syndrome toxin-1 (TSST-1) in their crystallographic assemblies with HLA-DR1. Rigid-body do... |
9770651 | Molecular recognition of a peptide mimic of the Lewis Y antigen by an anti-Lewis Y antibody. | Peptides as mimics of carbohydrates display a distinct advantage in vaccine design because of ease of synthesis and their inherent T cell-dependent nature as immunogens. While peptides that mimic carbohydrates have been described, it is not clear how they do so. To further our insight into structural relationships betw... |
9770650 | Concerning the separation of mammalian cells in immobilized metal ion affinity partitioning systems: a matter of selectivity. | The effect of introducing an immobilized metal ion ligand in the lower phase of the PEG/Dextran system was studied on the erythrocytes and lymphocytes partition. The ligand in the lower phase was added as an insoluble form [Sepharose-IDA-M(II)] with or without a ligand in the upper phase. We first checked that the addi... |
9770649 | NMR study and comparison of the antigenic properties of a peptide recognized by two HIV-1 neutralizing antibodies. | Fab-peptide complexes formed between a 15 residue peptide derived from the HIV-1 gp120 V3 loop and two of its cognate monoclonal antibodies, 5023A and 5025A, were studied using isotope-edited solution nuclear magnetic resonance (NMR) techniques. Since these antibodies neutralize HIV-1 virus with different strain specif... |
9770648 | DNA binding properties of minor groove binders and their influence on the topoisomerase II cleavage reaction. | We present titrations of the human delta beta-globin gene region with DNA minor groove binders netropsin, bisnetropsin, distamycin, chromomycin and four bis-quaternary ammonium compounds in the presence of calf thymus topoisomerase II and DNase I. With increasing ligand concentration, stimulation and inhibition of enzy... |
9768468 | Mapping cell wall polysaccharides of living microbial cells using atomic force microscopy. | Functionalized atomic force microscope tips were used to sense specific forces of interaction between ligand-receptor pairs and to map the positions of polysaccharides on a living microbial cell surface. Gold-coated tips were functionalized with concanavalin A using a cross-linker with a spacer arm of 15.6 A. It was po... |
17029906 | Electron transfer and electronic energy relaxation under high hydrostatic pressure. | The following question has been addressed in the present work. How external high (up to 8 kbar) hydrostatic pressure acts on photoinduced intramolecular electron transfer and on exciton relaxation processes? Unlike phenomena, as they are, have been studied in different systems: electron transfer in an artificial Zn-por... |
11671819 | Novel Resorcinarene Cavitand-Based CMP(O) Cation Ligands: Synthesis and Extraction Properties. | Tetrafunctionalized resorcinarene cavitands (4-6) have been synthesized starting from tetrakis(bromomethyl)cavitand 3. New cavitand-based cation ligands with (carbamoylmethyl)phosphonate (CMP) and -phosphine oxide (CMPO) moieties (8a,b and 9a,b) were prepared via two different routes in good (45-86%) overall yields. Th... |
11671817 | Sulfones as Radical Progenitors: An Unprecedented Example of Homolytic Sulfone Cleavage Facilitated by o-Stannyl Substitution of Aryl Sulfones(1). | Allylic aryl sulfones bearing an o-allyldialkylstannyl moiety (1b), when converted to stannyl radical 1a, suffer homolytic cleavage via intramolecular attack of the stannyl radical on the sulfone. Allyl radicals generated in this manner can be utilized for further intramolecular radical cyclizations; thus the overall t... |
11670150 | Multicomponent Self-Assembly: Generation of Rigid-Rack Multimetallic Pseudorotaxanes. | The rigid linear ligands 1a-g and the macrocycle 2 undergo self-assembly via coordination with copper(I) ions to generate the series of rigid-rack inorganic pseudorotaxanes 3a-g. These complexes have been characterized by analytical and spectroscopic methods. Their architecture has been confirmed by determination of th... |
9463949 | 2(k-p) fractional factorial design via fold over: application to optimization of novel multicomponent vesicular systems. | A computer-based technique based on a 2(k-p) fractional factorial design was applied for the optimization of recently described multicomponent protective liposomal formulations. These formulations contain riboflavin (vitamin B2) as a model, photosensitive drug, in addition to Oil Red O, deoxybenzone, oxybenzone and bet... |
9440354 | NMR study of per(3,6-anhydro) alpha cyclodextrin as a potential agent for the biological decontamination of lead. | The ability of per(3,6-anhydro) alpha cyclodextrin(3,6CD) to capture lead from a preformed glutathion (GSH)-lead complex was investigated by NMR spectroscopy. Such a removal strongly depends on the nature and pH of the buffer used in the competition experiments. It was found that an almost complete removal of lead can ... |
9430414 | Subtype-selective antagonism of NMDA receptors by nylidrin. | The 1,4-di-substituted piperidines ifenprodil, eliprodil, CP 101,606 ((1S,2S)-1-(4-hydroxyphenyl)-2-(4-hydroxy-4-phenylpiperidino)-1-propanol ) and Ro 25-6981 ((R-(R*,S*))-alpha-(4-hydroxyphenyl)-beta-methyl-4-(phenyl-methyl)-1- piperidinepropanol) are allosteric antagonists of NMDA receptors. Inhibition of diheteromer... |
9413552 | Psychrophilic enzymes: molecular basis of cold adaptation. | Psychrophilic organisms have successfully colonized polar and alpine regions and are able to grow efficiently at sub-zero temperatures. At the enzymatic level, such organisms have to cope with the reduction of chemical reaction rates induced by low temperatures in order to maintain adequate metabolic fluxes. Thermal co... |
9412832 | The effect of heparinization on intra-abdominal infection and acute pulmonary failure. | <h4>Unlabelled</h4>Acute severe purulent peritonitis is still a very life-threatening disease condition. The primary cause of death is multiple organ failure (MOF) where acute respiratory distress syndrome (ARDS) is the initial trigger. Studies have shown that heparin has a cytoprotective effect and stimulates an incre... |
9408855 | Determination of salbutamol enantiomers by high-performance capillary electrophoresis and its application to dissolution assays. | Capillary zone electrophoresis was successfully applied to the chiral separation of salbutamol after addition of a suitable cyclodextrin chiral selector to the electrophoresis buffer. Parameters important in achieving enantiomeric separation are cyclodextrin type, mobile phase pH and applied field strength. In our stud... |
9408845 | The indirect UV detection in the analysis of ursodeoxycholic acid and related compounds by HPCE. | A high-performance capillary zone electrophoretic (HPCE) assay has been developed for the determination of ursodeoxycholic acid (UDCA) and its usual impurities. Considering the low molecular absorptivity of UDCA and its related compounds indirect UV detection was used. The electrophoretic capillary was filled with a ba... |
9408844 | Evaluation of the methods for the determination of the stability constant of cyclodextrin-chlorambucil inclusion complexes. | The interaction of the antitumor agent chlorambucil (CHL) with three different cyclodextrins (CD), namely methyl-beta CD (Me beta CD) polymer-beta CD (poly-beta CD) and gamma CD, is examined kinetically and spectrophotometrically, monitoring the hydrolysis and the changes in the UV absorbance of CHL respectively, in th... |
9408842 | Novel non-acidic formulations of haloperidol complexed with beta-cyclodextrin derivatives. | Haloperidol (Hal), a highly hydrophobic drug, was complexed with two beta-cyclodextrin (beta-CD) derivatives. Hal solubility was increased 20-fold in the presence of a 10-fold excess of methyl beta-CD (Me beta-CD) and 12-fold in the presence of a 10-fold excess of 2-hydroxypropyl beta-CD (HP beta-CD). The stoichiometri... |
9408835 | Analysis of amino acid enantiomers derived from antitumor antibiotics using chiral capillary electrophoresis. | The chiral separation of enantiomeric forms of derivatized amino acids have been achieved based on a metalchelate chiral capillary electrophoretic method and a cyclodextrin mediated host-guest interaction approach in micellar electrokinetic chromatography (MEKC) mode with laser-induced fluorescence detection. This appr... |
9403988 | Synthesis of chromogenic substrates of alpha-amylases on a cyclodextrin basis. | One-pot acetylation and subsequent partial acetolysis of alpha-, beta- and gamma-cyclodextrins resulted in crystalline peracetylated malto-hexaose, -heptaose, and -octaose, respectively. Prolonged acetolysis of beta-cyclodextrin gave a mixture of acetylated maltooligosaccharides, from which peracetylated malto-triose, ... |
9390454 | Characterization of Leuconostoc mesenteroides NRRL B-512F dextransucrase (DSRS) and identification of amino-acid residues playing a key role in enzyme activity. | Dextransucrase (DSRS) from Leuconostoc mesenteroides NRRL B-512F is a glucosyltransferase that catalyzes the synthesis of soluble dextran from sucrose or oligosaccharides when acceptor molecules, like maltose, are present. The L. mesenteroides NRRL B-512F dextransucrase-encoding gene (dsrS) was amplified by the polymer... |
9390725 | Enantioselective high-performance liquid chromatography determination of methadone enantiomers and its major metabolite in human biological fluids using a new derivatized cyclodextrin-bonded phase. | The simultaneous determination of methadone (Mtd) enantiomers and its major metabolite, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), in human urine and serum by enantioselective HPLC using a new Cyclobond 1-2000 RSP column is described. After alkaline extraction from urine or serum with estazolam as an int... |
9390715 | Capillary electrophoresis of glutamate and aspartate in rat brain dialysate. Improvements in detection and analysis time using cyclodextrins. | Addition of cyclodextrins (CDs) to the electrolyte buffer in the capillary zone electrophoresis (CZE) separation of derivatized amino acids was evaluated in terms of fluorescence signal enhancement, resolution, and migration time effects. Maximum fluorescence signal enhancement was observed with separation buffers cont... |
9375254 | Molecular recognition of diketide substrates by a beta-ketoacyl-acyl carrier protein synthase domain within a bimodular polyketide synthase. | <h4>Background</h4>Modular polyketide synthases (PKSs) are large multifunctional proteins that catalyze the biosynthesis of structurally complex bioactive products. The modular organization of PKSs has allowed the application of a combinatorial approach to the synthesis of novel polyketides via the manipulation of thes... |
9372421 | Unresponsive HIV-related oro-oesophageal candidosis--an evaluation of two new in-vitro azole susceptibility tests. | Azole-resistant HIV-related candidosis is increasingly recognized. We evaluated two new in-vitro susceptibility tests (the NCCLS proposed MIC method and Odds' assessment of relative growth in single anti-fungal concentration) as predictors of the clinical outcome of 66 HIV-positive patients with oral candidosis, of who... |
9370033 | The design, synthesis and transmembrane transport studies of a biomimetic sterol-based ion channel. | A model sterol-based ion channel was rationally designed and synthesized. The potential ion channel is comprised of a tartrate-derived crown ether to which six steroids are appended. Macromolecule 1a was incorporated into phospholipid vesicles and shown to facilitate the transmembrane transport of sodium and lithium io... |
9370308 | Sequence analysis and expression of the polyhedrin gene of Choristoneura fumiferana cytoplasmic polyhedrosis virus (CfCPV). | The segmented double-stranded RNA genome of Choristoneura fumiferana cytoplasmic polyhedrosis virus (CfCPV) was extracted, polyadenylated, reverse-transcribed into cDNA and cloned. The cDNA clones that hybridized to the smallest genomic segment (segment 10) were identified, and its nucleotide sequence was determined. G... |
9370256 | Conformational studies of synthetic lipid A analogues and partial structures by infrared spectroscopy. | Synthetic lipid A analogues and partial structures were analyzed and compared with natural hexaacyl lipid A from E. coli applying Fourier transform infrared spectroscopy. The investigations comprised (i) the measurement of the beta <=> alpha phase transition of the acyl chains via monitoring of the symmetric stretching... |
9368648 | Structure, recognition and adaptive binding in RNA aptamer complexes. | Novel features of RNA structure, recognition and discrimination have been recently elucidated through the solution structural characterization of RNA aptamers that bind cofactors, aminoglycoside antibiotics, amino acids and peptides with high affinity and specificity. This review presents the solution structures of RNA... |
9369219 | Did cyclodextrin glycosyltransferases evolve from alpha-amylases? | The hydrolytic enzymes, alpha-amylases, and the cyclodextrin glycosyltransferases (CGTases) are key enzymes in the depolymerization of starch. These two groups of enzymes are evolutionarily related. We propose that the transferase activity is likely to have evolved from an ancestral hydrolase. Sequence analysis provide... |
9364400 | Measurement of molecular association in drug: cyclodextrin inclusion complexes with improved 1H NMR studies. | The molecular association of haloperidol with hydroxypropyl-beta-cyclodextrin, expressed by the binding constant of the inclusion complex formed, was calculated from the changes on the 1H NMR spectra of the drug in the presence of the cyclodextrin. The stoichiometry of the complex was calculated by use of the continuou... |
9364927 | The Srp40 protein plays a dose-sensitive role in preribosome assembly or transport and depends on its carboxy-terminal domain for proper localization to the yeast nucleoskeleton. | The yeast SRP40 gene product (Srp40p) is a highly serine-rich protein organized in three distinct domains. The roles of these domains in localizing Srp40p were determined. By indirect immunofluorescence microscopy, Srp40p localizes to punctate, sometimes fibrillar, subnuclear structures that might include the nucleolus... |
9361586 | Bacterial translocation in multiple organ failure: cause or epiphenomenon still unproven. | <h4>Background</h4>A body of evidence exists for the occurrence of bacterial translocation and its relationship to multiple organ failure (MOF).<h4>Methods</h4>Relevant articles on bacterial translocation (the phenomenon defined as the passage of microbes and endotoxin across the intestinal barrier) in patients prone t... |
9380503 | Detection and isolation of RNA-binding proteins by RNA-ligand screening of a cDNA expression library. | A screening assay for the detection of RNA-binding proteins was developed. It allows the rapid isolation of cDNA clones coding for proteins with sequence-specific binding affinity to a target RNA. For developing the screening protocol, constituents of the human U1 snRNP were utilized as model system. The RNA partner co... |
9376362 | Leucine is the most stabilizing aliphatic amino acid in the d position of a dimeric leucine zipper coiled coil. | The energetic contribution of seven amino acids in the d position of a dimeric leucine zipper coiled coil structure was measured by determining the thermal stability. The d position contains the conserved leucines found in the leucine zipper. We used a natural bZIP protein as our host-guest system that remains dimeric ... |
9376359 | Minor groove-directed and intercalative ligand-DNA interactions in the poisoning of human DNA topoisomerase I by protoberberine analogs. | Spectroscopic, calorimetric, DNA cleavage, electrophoretic, and computer modeling techniques have been employed to characterize the DNA binding and topoisomerase poisoning properties of three protoberberine analogs, 8-desmethylcoralyne (DMC), 5,6-dihydro-8-desmethylcoralyne (DHDMC), and palmatine, which differ in the c... |
9358641 | Characterization of anticholinesterase-active 3-alkylpyridinium polymers from the marine sponge Reniera sarai in aqueous solutions. | From the marine sponge Reniera sarai 3-alkylpyridinium oligomers and polymers have been isolated. 3-Alkylpyridinium polymers are potent anticholinesterase agents; in addition, they show hemolytic and cytotoxic activities. Oligomers with a molecular weight lower than 3000 Da do not possess any significant activity. We r... |
9358553 | Protection afforded by maltosyl-beta-cyclodextrin against alpha-chymotrypsin-catalyzed hydrolysis of a luteinizing hormone-releasing hormone agonist, buserelin acetate. | <h4>Purpose</h4>The present study addresses how maltosyl-beta-cyclodextrin (G2-beta-CyD) impacts upon the alpha-chymotrypsin-catalyzed hydrolysis of buserelin acetate, an agonist of luteinizing hormone-releasing hormone with emphasis upon the direct effect of G2-beta-CyD on the activity of the protease.<h4>Methods</h4>... |
9352294 | Sulfated polysaccharides extracted from sea algae as potential antiviral drugs. | The inhibitory effects of polyanionic substances on the replication of herpes simplex virus (HSV) and other viruses were reported almost four decades ago. However, these observations did not generate much interest, because the antiviral action of the compounds was considered to be largely nonspecific. Shortly after the... |
9353127 | Structure of the cyclin-dependent kinase inhibitor p19Ink4d. | In cancer, the biochemical pathways that are dominated by the two tumour-suppressor proteins, p53 and Rb, are the most frequently disrupted. Cyclin D-dependent kinases phosphorylate Rb to control its activity and they are, in turn, specifically inhibited by the Ink4 family of cyclin-dependent kinase inhibitors (CDKIs) ... |
9348541 | The rat myosin myr 5 is a GTPase-activating protein for Rho in vivo: essential role of arginine 1695. | myr 5 is an unconventional myosin (class IX) from rat that contains a Rho-family GTPase-activating protein (GAP) domain. Herein we addressed the specificity of the myr 5 GAP activity, the molecular mechanism by which GAPs activate GTP hydrolysis, the consequences of myr 5 overexpression in living cells, and its subcell... |
9344867 | Asp278 of human beta-adrenergic receptor kinase 1 is essential for phosphorylation activity. | Asp278 of beta-adrenergic receptor kinase 1 (betaARK1) was suggested to play a key role in substrate recognition of beta2-adrenergic receptors in our previous study, in which a three-dimensional model of betaARK1 was studied in comparison with a crystal structure of PKA-PKI5-24 complex. In the present study, to confirm... |
9344743 | Nucleosomes: a solution to a crowded intracellular environment? | The emergence of eukaryotes was accompanied by two major events that concern their genome and are of crucial significance when considered in terms of macromolecular crowding: (i) a substantial increase in the amount of DNA, and (ii) its confinement within a defined space. The resulting highly crowded environment would ... |
9349814 | Polymerized colloidal crystal hydrogel films as intelligent chemical sensing materials. | Chemical sensors respond to the presence of a specific analyte in a variety of ways. One of the most convenient is a change in optical properties, and in particular a visually perceptible colour change. Here we report the preparation of a material that changes colour in response to a chemical signal by means of a chang... |
9344610 | TGF-alpha-induced breakdown of stress fibers and degradation of tropomyosin in NRK cells is blocked by a proteasome inhibitor. | Treatment of NRK cells with TGF-alpha in the presence of serum initiates disassembly of cytoskeletal stress fibers and suppresses the synthesis of tropomyosin isoforms (TMs) 1, 2, and 3 but not TMs 4 and 5 (Cooper et al., Cancer Res. 47, 4493-4500, 1987). In order to determine how the loss of tropomyosin is induced and... |
9344585 | Reduced epidermal expression of a PG-M/versican-like proteoglycan in embryos of the white mutant axolotl. | Axolotl embryos have previously been used to study neural crest cell migration. In embryos of the normal wild type, neural crest cells migrate subepidermally to form pigment cells. In the trunk of the white mutant embryo, these cells are unable to migrate, possibly due to an inherited delay in the maturation of the loc... |
9342383 | The interaction between cytoplasmic dynein and dynactin is required for fast axonal transport. | Fast axonal transport is characterized by the bidirectional, microtubule-based movement of membranous organelles. Cytoplasmic dynein is necessary but not sufficient for retrograde transport directed from the synapse to the cell body. Dynactin is a heteromultimeric protein complex, enriched in neurons, that binds to bot... |
9342358 | Incomplete penetrance of familial retinoblastoma linked to germ-line mutations that result in partial loss of RB function. | To study the molecular basis for the clinical phenotype of incomplete penetrance of familial retinoblastoma, we have examined the functional properties of three RB mutations identified in the germ line of five different families with low penetrance. RB mutants isolated from common adult cancers and from classic familia... |
9342323 | Synthesis and screening of small molecule libraries active in binding to DNA. | Five synthetic combinatorial libraries of 2,080 components each were screened as mixtures for inhibition of DNA binding to two transcription factors. Rapid, solution-phase synthesis coupled to a gel-shift assay led to the identification of two compounds active at a 5- to 10-microM concentration level. The likely mode o... |
9342316 | Characterization of recombinant phytochrome from the cyanobacterium Synechocystis. | The complete sequence of the Synechocystis chromosome has revealed a phytochrome-like sequence that yielded an authentic phytochrome when overexpressed in Escherichia coli. In this paper we describe this recombinant Synechocystis phytochrome in more detail. Islands of strong similarity to plant phytochromes were found ... |
9344168 | Binding, uptake, and transport of hypericin by Caco-2 cell monolayers. | The biological evaluation of hypericin in various test models is hampered by its very poor water solubility. In the present study cyclodextrin formulations and liposomal preparations were investigated for improved delivery and solubility of hypericin in aqueous buffer systems. Caco-2 cells, grown to tight monolayers on... |
9336846 | Conformationally driven protease-catalyzed splicing of peptide segments: V8 protease-mediated synthesis of fragments derived from thermolysin and ribonuclease A. | We have studied the conformation as well as V8 protease-mediated synthesis of peptide fragments, namely amino acid residues 295-316 (TC-peptide) of thermolysin and residues 1-20 (S-peptide) of ribonuclease A, to examine whether "conformational trapping" of the product can facilitate reverse proteolysis. The circular di... |
9336844 | Oligomerization properties of GCN4 leucine zipper e and g position mutants. | Putative intersubunit electrostatic interactions between charged amino acids on the surfaces of the dimer interfaces of leucine zippers (g-e' ion pairs) have been implicated as determinants of dimerization specificity. To evaluate the importance of these ionic interactions in determining the specificity of dimer format... |
9336671 | A primer on cytokines: sources, receptors, effects, and inducers. | Protection against pathogens is a prerequisite for survival of most organisms. To cope with this continuous challenge, complex defense mechanisms have evolved. The construction, adaptation, and maintenance of these mechanisms are under control of an extensive network of regulatory proteins called cytokines. A great num... |
9336670 | Helicobacter pylori. | Helicobacter pylori is a gram-negative bacterium which causes chronic gastritis and plays important roles in peptic ulcer disease, gastric carcinoma, and gastric lymphoma. H. pylori has been found in the stomachs of humans in all parts of the world. In developing countries, 70 to 90% of the population carries H. pylori... |
9334346 | The microtubule-dependent motor centromere-associated protein E (CENP-E) is an integral component of kinetochore corona fibers that link centromeres to spindle microtubules. | Centromere-associated protein E (CENP-E) is a kinesin-related microtubule motor protein that is essential for chromosome congression during mitosis. Using immunoelectron microscopy, CENP-E is shown to be an integral component of the kinetochore corona fibers that tether centromeres to the spindle. Immediately upon nucl... |
9334344 | Analysis of the actin-myosin II system in fish epidermal keratocytes: mechanism of cell body translocation. | While the protrusive event of cell locomotion is thought to be driven by actin polymerization, the mechanism of forward translocation of the cell body is unclear. To elucidate the mechanism of cell body translocation, we analyzed the supramolecular organization of the actin-myosin II system and the dynamics of myosin I... |
9335560 | Linkage between operator binding and dimer to octamer self-assembly of bacteriophage lambda cI repressor. | Cooperative binding of the bacteriophage lambda cI repressor dimer to specific sites of the phage operators OR and OL controls the developmental state of the phage. Cooperativity has long been thought to be mediated by self-assembly of repressor dimers to form tetramers which can bind simultaneously to adjacent operato... |
9335596 | Homology-dependent silencing of the SC3 gene in Schizophyllum commune. | After introduction of extra copies of the SC3 hydrophobin gene into a wild-type strain of Schizophyllum commune, gene silencing was observed acting on both endogenous and introduced SC3 genes in primary vegetative transformants. Nuclear run-on experiments indicated that silencing acted at the transcriptional level. Sou... |
9335590 | The role of Gcr1p in the transcriptional activation of glycolytic genes in yeast Saccharomyces cerevisiae. | To study the interdependence of Gcr1p and Rap1p, we prepared a series of synthetic regulatory sequences that contained various numbers and combinations of CT-boxes (Gcr1p-binding sites) and RPG-boxes (Rap1p-binding sites). The ability of the synthetic oligonucleotides to function as regulatory sequences was tested usin... |
9336213 | Driving proteins off DNA using applied tension. | Proteins that bind DNA so as to reduce its end-to-end length can be dissociated by application of force. The thermodynamics of this process are discussed, with special attention to the case of histones bound to DNA (i.e., a string of nucleosomes, or chromatin fiber). The histone octamer is predicted to be driven off ch... |
9336212 | Self-assembly of collagen fibers. Influence of fibrillar alignment and decorin on mechanical properties. | Collagen is the primary structural element in extracellular matrices. In the form of fibers it acts to transmit forces, dissipate energy, and prevent premature mechanical failure in normal tissues. Deformation of collagen fibers involves molecular stretching and slippage, fibrillar slippage, and, ultimately, defibrilla... |
9336207 | Involvement of water molecules in the association of monoclonal antibody HyHEL-5 with bobwhite quail lysozyme. | Fluorescence polarization spectroscopy and isothermal titration calorimetry were used to study the influence of osmolytes on the association of the anti-hen egg lysozyme (HEL) monoclonal antibody HyHEL-5 with bobwhite quail lysozyme (BWQL). BWQL is an avian species variant with an Arg-->Lys mutation in the HyHEL-5 epit... |
9336200 | Guanine tetraplex formation by short DNA fragments containing runs of guanine and cytosine. | Using CD spectroscopy, guanine tetraplex formation was studied with short DNA fragments in which cytosine residues were systematically added to runs of guanine either at the 5' or 3' ends. Potassium cations induced the G-tetraplex more easily with fragments having the guanine run at the 5' end, which is just an opposit... |
9336183 | Pore residues critical for mu-CTX binding to rat skeletal muscle Na+ channels revealed by cysteine mutagenesis. | We have studied mu-conotoxin (mu-CTX) block of rat skeletal muscle sodium channel (rSkM1) currents in which single amino acids within the pore (P-loop) were substituted with cysteine. Among 17 cysteine mutants expressed in Xenopus oocytes, 7 showed significant alterations in sensitivity to mu-CTX compared to wild-type ... |
9336172 | Liquid crystalline ordering of nucleosome core particles under macromolecular crowding conditions: evidence for a discotic columnar hexagonal phase. | Macromolecular crowding conditions occurring inside the cell nucleus were reproduced experimentally with solutions of mononucleosome core particles to study their supramolecular organization. We report here that under these conditions, and over a large range of monovalent salt concentrations, mononucleosome core partic... |
9336170 | Configurational transitions in Fourier series-represented DNA supercoils. | A new Fourier series representation of supercoiled DNA is employed in Langevin dynamics simulations to study large-scale configurational motions of intermediate-length chains. The polymer is modeled as an ideal elastic rod subject to long-range van der Waals' interactions. The van der Waals' term prevents the self-cont... |
9336169 | Wetting and capillary condensation as means of protein organization in membranes. | Wetting and capillary condensation are thermodynamic phenomena in which the special affinity of interfaces to a thermodynamic phase, relative to the stable bulk phase, leads to the stabilization of a wetting phase at the interfaces. Wetting and capillary condensation are here proposed as mechanisms that in membranes ma... |
9334322 | Topoisomerase IV, not gyrase, decatenates products of site-specific recombination in Escherichia coli. | DNA replication and recombination generate intertwined DNA intermediates that must be decatenated for chromosome segregation to occur. We showed recently that topoisomerase IV (topo IV) is the only important decatenase of DNA replication intermediates in bacteria. Earlier results, however, indicated that DNA gyrase has... |
9334320 | AU-rich elements target small nuclear RNAs as well as mRNAs for rapid degradation. | AU-rich elements (AREs, usually containing repeated copies of AUUUA), when present in the 3'-untranslated regions (UTRs) of many mammalian mRNAs, confer instability on their host RNA molecules. The viral small nuclear RNA (snRNA) Herpesvirus saimiri U RNA 1 (HSUR 1) also contains an AUUUA-rich sequence. Here, we report... |
9334312 | The PAG gene product, a stress-induced protein with antioxidant properties, is an Abl SH3-binding protein and a physiological inhibitor of c-Abl tyrosine kinase activity. | Biochemical and genetic evidence suggests that the tyrosine kinase activity of c-Abl is tightly regulated in vivo by a cellular factor binding to the Src homology 3 (SH3) domain of Abl. We used the yeast two-hybrid system to identify a gene, PAG, whose protein product (Pag) interacts specifically with the Abl SH3 domai... |
9335508 | Survival of FimH-expressing enterobacteria in macrophages relies on glycolipid traffic. | Strains of Escherichia coli persist within the human gut as normal commensals, but are frequent pathogens and can cause recurrent infection. Here we show that, in contrast to E. coli subjected to opsonic interactions stimulated by the host's immune response, E. coli that bind to the macrophage surface exclusively throu... |
9335289 | Identification of human transferrin-binding sites within meningococcal transferrin-binding protein B. | Transferrin-binding protein B (TbpB) from Neisseria meningitidis binds human transferrin (hTf) at the surface of the bacterial cell as part of the iron uptake process. To identify hTf binding sites within the meningococcal TbpB, defined regions of the molecule were produced in Escherichia coli by a translational fusion... |
9335282 | Factors controlling in vitro recrystallization of the Caulobacter crescentus paracrystalline S-layer. | The S-layer of Caulobacter is a two-dimensional paracrystalline array on the cell surface composed of a single protein, RsaA. We have established conditions for preparation of stable, soluble protein and then efficient in vitro recrystallization of the purified protein. Efficient recrystallization and long range order ... |
9335276 | Bacillus subtilis PhoP binds to the phoB tandem promoter exclusively within the phosphate starvation-inducible promoter. | Several gene products, including three two-component systems, make up a signal transduction network that controls the phosphate starvation response in Bacillus subtilis. Epistasis experiments indicate that PhoP, a response regulator, is furthest downstream of the known regulators in the signaling pathway that regulates... |
9333030 | Comparison of the efficacies of various formulations of amphotericin B against murine visceral leishmaniasis. | The antileishmanial efficacies of four proprietary amphotericin B (AmB) formulations (Fungizone, AmBisome, Abelcet, and Amphocil) and an experimental nonionic surfactant vesicle (NIV) formulation were compared in a murine model of acute visceral leishmaniasis. By a multiple-dosing regimen, groups of Leishmania donovani... |
9330864 | CEA adhesion molecules: multifunctional proteins with signal-regulatory properties. | The carcinoembryonic antigen family comprises a large number of complex molecules, several of which possess cell adhesion activities. The primordial adhesion molecules of this family are the cell-cell adhesion molecules (C-CAMs), which have been found to be multifunctional, signal-regulatory proteins. C-CAMs inhibit tu... |
9330513 | [Surgical results of emergency coronary artery bypass grafting: effect of left main trunk lesion]. | Emergency coronary artery bypass grafting has higher risk than elective surgery. Furthermore, if a lesion is located at left main coronary artery, the frequency of cardiogenic shock or high risk patient would be greater, and operative results would be worse. Between January, 1989 and December, 1995, 45 patients who und... |
9326672 | A peptide derived from an extracellular domain selectively inhibits receptor internalization: target sequences on insulin and insulin-like growth factor 1 receptors. | Certain peptides derived from the alpha1 domain of the major histocompatibility class I antigen complex (MHC-I) inhibit receptor internalization, increasing the steady-state number of active receptors on the cell surface and thereby enhancing the sensitivity to hormones and other agonists. These peptides self-assemble,... |
9326617 | Role of lipid polymorphism in G protein-membrane interactions: nonlamellar-prone phospholipids and peripheral protein binding to membranes. | Heterotrimeric G proteins (peripheral proteins) conduct signals from membrane receptors (integral proteins) to regulatory proteins localized to various cellular compartments. They are in excess over any G protein-coupled receptor type on the cell membrane, which is necessary for signal amplification. These facts accoun... |
9326613 | A transformation-associated complex involving tyrosine kinase signal adapter proteins and caldesmon links v-erbB signaling to actin stress fiber disassembly. | The avian erythroblastosis viral oncogene (v-erbB) encodes a receptor tyrosine kinase that possesses sarcomagenic and leukemogenic potential. We have expressed transforming and nontransforming mutants of v-erbB in fibroblasts to detect transformation-associated signal transduction events. Coimmunoprecipitation and affi... |
9326606 | Raman spectral evidence for hydration forces between collagen triple helices. | Hydration forces are thought to result from the energetic cost of water rearrangement near macromolecular surfaces. Raman spectra, collected on the same collagen samples on which these forces were measured, reveal a continuous change in water hydrogen-bonding structure as a function of separation between collagen tripl... |
9326602 | Subtle atomic group discrimination in the RNA minor groove. | As a problem in molecular recognition and for drug discovery, great interest has developed around the possibility that RNA structures could be discriminated by peptides and other small molecules. Although small peptides have been shown to have the capacity to discriminate specific bulges and loops in RNA molecules, dis... |
9326577 | An artificial cytochrome P450 that hydroxylates unactivated carbons with regio- and stereoselectivity and useful catalytic turnovers. | A catalyst has been synthesized comprising a manganese porphyrin carrying four beta-cyclodextrin groups. It catalyzes the hydroxylation of substrates of appropriate size carrying tert-butylphenyl groups that can hydrophobically bind into the cyclodextrin cavities. In one example as many as 650 catalytic turnovers are s... |
9331095 | Intratumoral delivery of boronated epidermal growth factor for neutron capture therapy of brain tumors. | The gene for epidermal growth factor receptor (EGFR) is amplified or overexpressed in high-grade gliomas but is low or undetectable in normal brain. Recently, there has been increasing interest in using epidermal growth factor (EGF)-based bioconjugates as targeting agents for brain tumors. In the present study, we have... |
9329087 | Correlation of the enzyme activities of Bacillus stearothermophilus lactate dehydrogenase on three substrates with the results of molecular dynamics/energy minimization conformational searching. | Current methods for reengineering enzyme substrate specificities rely heavily on the use of static x-ray crystallographic models. In this article we detail the use of a molecular mechanics approach for suggesting regions of Bacillus stearothermophilus L-lactate dehydrogenase (EC 1.1.1.27) involved in substrate specific... |
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