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2459611 | Immunological evidence for differences in the exposed regions of OmpF porins from Escherichia coli B and K-12. | Nine monoclonal antibodies (MoF 0-8) directed against the native form (trimeric) of outer membrane protein OmpF of Escherichia coli B were obtained and characterized. All these antibodies bind to OmpF porin in intact E. coli B cells but not OmpF from E. coli K-12 cells which only differ at positions 66, 117 and 262 in ... |
3171933 | Inclusion complex formation of 1,8-dihydroxyanthraquinone with cyclodextrins in aqueous solution and in solid state. | Complex formation between cyclodextrins and 1,8-dihydroxyanthraquinone in buffer solution has been investigated using absorption, its second derivative (D2), and fluorescence spectroscopy. The results showed that whereas the self-association process was found for 1,8-dihydroxyanthraquinone alone, the monomeric form is ... |
2844528 | Isolation and characterization of the Tn3 resolvase synaptic intermediate. | We have isolated in quantitative yield the synaptic intermediate formed during site-specific recombination by Tn3 resolvase and characterized it by restriction endonuclease mapping, electron microscopy and topological methods. The intermediate accumulates at low reaction temperatures and is stabilized by crosslinking o... |
3048249 | Insulin-induced myosin light-chain phosphorylation during receptor capping in IM-9 human B-lymphoblasts. | We have examined further the interaction between insulin surface receptors and the cytoskeleton of IM-9 human lymphoblasts. Using immunocytochemical techniques, we determined that actin, myosin, calmodulin and myosin light-chain kinase (MLCK) are all accumulated directly underneath insulin-receptor caps. In addition, w... |
3048248 | Effect of specific proteolytic cleavages on tubulin polymer formation. | The capacity for self-polymerization and shape of the tubulin polymers assembled after digestion with trypsin, Pronase, chymotrypsin, subtilisin, Staphylococcus aureus proteinase V8 and proteinase K were investigated. Digestion with trypsin, Pronase or chymotrypsin resulted in a decrease in the ability of tubulin for s... |
3047637 | Comparative biochemical and morphometric studies on corneal wound healing. | Comparative biochemical and morphological studies were carried out on wounded corneas in order to correlate biochemical findings with morphometric observations during the healing process. Experimental production of corneal wounds, biochemical determinations and quantitative morphometric studies are described in an atte... |
3418711 | The use of thermally activated tritium atoms for structural-biological investigations: the topography of the TMV protein-accessible surface of the virus. | Thermally activated tritium atoms were used for studying the topography of the TMV protein-accessible surface of the virus. The accessibility profile of amino acid residues in a protein polypeptide chain was determined from data on the intramolecular distribution of a tritium label in the TMV protein. It was shown that... |
3417211 | [Studies on benexate.CD: effect of inclusion compound formation on the antiulcer activity of benexate, the effective ingredient of benexate.CD]. | Benexate.CD, a new orally active antiulcer agent, is an inclusion compound of benexate and beta-cyclodextrin (beta-CD). The present report investigated the significance of complex formation on the antiulcer activity of benexate, the effective ingredient of benexate.CD. To evaluate the improvement of solubility, the dis... |
3415657 | Purification and characterization of a highly thermostable novel pullulanase from Clostridium thermohydrosulfuricum. | Clostridium thermohydrosulfuricum mutant Z 21-109 produced intracellular thermostable pullulanase and glucoamylase activities. The glucoamylase activity was inactivated by treating C. thermohydrosulfuricum cells with 10% (v/v) propan-1-ol at 85 degrees C in the presence of 5 mM-CaCl2. Pullulanase activity was selective... |
3294100 | Unlinked noncomplementation: isolation of new conditional-lethal mutations in each of the tubulin genes of Saccharomyces cerevisiae. | Mutations in genes of Saccharomyces cerevisiae that code for proteins that interact with beta-tubulin were sought by screening for unlinked mutations that fail to complement mutations in the single beta-tubulin-encoding gene (TUB2). Among the first three noncomplementing mutations examined, two are linked to TUB2 while... |
3386226 | Estrogen receptor binding affinity and uterotrophic activity of triphenylhaloethylenes. | Radiohalogenated estrogens have considerable potential for estrogen receptor-directed imaging and therapy for cancers which contain such receptors. In an effort to evaluate the potential of the triphenyl ethylene structure for such purposes we have synthesized 3 series of 2-halosubstituted triphenylethylenes containing... |
3384857 | The Chlamydomonas cell wall degrading enzyme, lysin, acts on two substrates within the framework of the wall. | The Chlamydomonas cell wall is a multilayered, extracellular matrix containing 20-25 proteins and glycoproteins, many of which are highly enriched in hydroxyproline. 80-90% of the wall protein is located in a crystalline portion of the wall that is soluble in sarkosyl-urea solutions as well as in chaotropic salts. Alth... |
3384852 | Purified thick filaments from the nematode Caenorhabditis elegans: evidence for multiple proteins associated with core structures. | The thick filaments of the nematode, Caenorhabditis elegans, arising predominantly from the body-wall muscles, contain two myosin isoforms and paramyosin as their major proteins. The two myosins are located in distinct regions of the surfaces, while paramyosin is located within the backbones of the filaments. Tubular s... |
2454472 | Three-dimensional model of the capsid proteins of two biologically different Theiler virus strains: clustering of amino acid difference identifies possible locations of immunogenic sites on the virion. | To explore structural features of the Theiler murine encephalomyelitis virion, we have constructed a three-dimensional model of the capsid proteins (VP1, VP2, and VP3) of the BeAn strain based on the atomic coordinates of the closely related Mengo virus. By superimposition of amino acid differences between BeAn virus a... |
3288994 | Site-specific binding of viral plus single-stranded RNA to replicase-containing open virus-like particles of yeast. | X double-stranded RNA is a deletion mutant of L-A double-stranded RNA and is encapsidated in viral particles by the L-A-encoded major coat protein. X double-stranded RNA has all the cis sites necessary to be transcribed, encapsidated, and replicated. We have cloned X double-stranded RNA and sequenced it. The complete X... |
3380783 | Crystal and molecular structure of didemnin B, an antiviral and cytotoxic depsipeptide. | Didemnin B, a highly active depsipeptide isolated from a Caribbean tunicate, crystallizes from chloroform/benzene in the orthorhombic space group C2221, with cell parameters a = 14.990 +/- 0.003 A, b = 22.574 +/- 0.004 A, c = 41.112 +/- 0.009 A, V = 13911.7 A3 at 138 K and a calculated density of 1.143 g/cm3 based on C... |
3288486 | Lamin disassembly kinetics: a cell-free system with extracts from mitotic HeLa cells. | We describe a cell-free system in which a postribosomal supernatant from metaphase HeLa cells induces prophase-like changes in permeabilized HeLa cell populations as evidenced by the nuclear lamin disassembly and chromatin condensation. We have attempted to characterize the cell-free system with permeabilized HeLa cell... |
3259602 | The intrinsic affinity constant (K) of anticapsular antibody to oligosaccharides of Haemophilus influenzae type b. | Antibody to the polyribosylribitol phosphate (PRP) capsular polysaccharide of Haemophilus influenzae type b is crucial to host defense. Affinities of antibody elicited by vaccination with PRP and PRP-diphtheria toxoid conjugate were determined using oligosaccharides (OS) from PRP. The affinities of antibody induced by ... |
3372479 | Isolation and biochemical characterization of the S-layer protein from a pathogenic Aeromonas hydrophila strain. | The regular surface protein array (S layer) present on Aeromonas hydrophila TF7 is composed of a single species of protein of apparent molecular weight 52,000. This protein was extracted from whole cells by treatment with 0.2 M glycine hydrochloride (pH 3.0). The protein was purified to homogeneity by ion-exchange chro... |
2836358 | Overproduction of single-stranded-DNA-binding protein specifically inhibits recombination of UV-irradiated bacteriophage DNA in Escherichia coli. | Overproduction of single-stranded DNA (ssDNA)-binding protein (SSB) in uvr Escherichia coli mutants results in a wide range of altered phenotypes. (i) Cell survival after UV irradiation is decreased; (ii) expression of the recA-lexA regulon is slightly reduced after UV irradiation, whereas it is increased without irrad... |
3285810 | Postoperative acute gastrointestinal tract hemorrhage and multiple-organ failure. | Acute upper gastrointestinal tract hemorrhage (AUGH) was evaluated postoperatively in 720 critically ill patients and correlated with multiple-organ failure (MOF). The AUGH incidence was 20.1%. Patients were divided into three groups. Group 1 (n = 77) patients were admitted without AUGH, but developed MOF and later AUG... |
2835497 | Interaction of the bovine papillomavirus type 1 E2 transcriptional control protein with the viral enhancer: purification of the DNA-binding domain and analysis of its contact points with DNA. | The E2 gene of bovine papillomavirus type 1 positively and negatively regulates the transcriptional enhancer located in the long control region of the viral genome. The DNA-binding domain of the E2 gene product was suspected to interact with the DNA sequence motif ACCN6GGT. We have shown that the carboxy-terminal 126 a... |
2835255 | ACTH peptides stimulate motor nerve sprouting in development. | Maturational changes at the neuromuscular junction (nmj) of rat neonates were studied using scanning electron microscopy and light microscopy that permitted quantification of muscle fiber diameter, length of nerve terminal branching, end-plate area, and perimeter. Administration of ACTH 4-10 (10 micrograms/kg s.c. dail... |
3255320 | Brain-enhanced delivery of testosterone using a chemical delivery system complexed with 2-hydroxypropyl-beta-cyclodextrin. | Enhanced brain delivery of testosterone was suggested by application of a dihydropyridine in equilibrium pyridinium salt redox system. The drug delivery method is based upon the NAD+ in equilibrium NADH coenzyme system and utilizes the covalent attachment of testosterone to a dihydropyridine-type carrier. Upon administ... |
2977184 | Photoproducts formed from photofrin II in cells. | Fluorescence and absorption spectra of light-exposed cells containing the tumour-localizing porphyrin preparation Photofrin II (PII) have been studied. Light exposure results in spectral changes that may be due to a photoinduced modification of the porphyrins without breakage of the porphyrin macrocycle and/or to a pho... |
2972916 | [Kinetic model of the action of oligomeric enzymes using phosphofructokinase as an example. II. General formulation of the hierarchical model]. | A general approach is suggested to describe the steady-state kinetics of the oligomeric enzymes on the base of the generalized statistical Ising model. Detailed analysis is given for the case of a oligomeric enzyme with a hierarchical supramolecular organization. A protomer of this enzyme composed of several equivalent... |
2460736 | [Genetically engineered mutants of the envelope protein of the RNA-containing bacteriophage]. | Expression of the coat protein gene of RNA bacteriophage fr in Escherichia coli cells leads to the formation of capsid-like structures of ca. 25 nm in diameter, which are immunologically indistinguishable from the native phage fr capsids. The modification strategy of the coat protein gene by gene engineering technique ... |
3174808 | Studies on cyclodextrin polymer. Part 1: The effect of CDP on indomethacin tablet formulation. | Cyclodextrin polymer (CDP), which is a cross-linked derivative of beta-cyclodextrin, has been used as binder and disintegrating agent in tablet formulation. In this study different tablet formulations of indomethacin, which is a nonsteroid anti-inflammatory drug were prepared by direct compression method. Corn starch, ... |
3415649 | The dimerization of half-molecule fragments of transferrin. | Partial proteolysis was used to prepare half-molecule fragments of hen ovotransferrin. N-Terminal and C-terminal fragments associate to form an N-terminal fragment-C-terminal fragment dimer. Variant forms of the N- and C-terminal fragments can be prepared in which a few amino acid residues are lacking from the C-termin... |
3046603 | A heparin-binding protein involved in inhibition of smooth-muscle cell proliferation. | A heparin-binding protein was isolated from bovine uteri and purified to homogeneity. This protein appears as a double band of approx. 78 kDa in SDS/polyacrylamide-gel electrophoresis and has an isoelectric point of 5.2. The binding of heparin to this protein is saturable. No other glycosaminoglycan from mammalian tiss... |
3410514 | Molecular recognition of human insulin receptor by autoantibodies in a human serum. | Immune IgG was obtained from a patient's serum with autoantibodies against human insulin receptor (HIR). The binding activity of these autoantibodies to seven synthetic peptides of the alpha-subunit of HIR was examined by radioimmuno-adsorbent titrations. Autoantibodies were bound by two of these peptides, namely alpha... |
2970398 | [Cardio- and hemodynamic effects of a crown ether derivative and an analysis of its cardiotropic action in an experiment]. | The cardio- and hemodynamic effects of the derivative of aza-15-crown-5 was studied in acute experiments on anesthetized (ethaminal sodium, 50 mg/kg) cats. At intravenous administration the compound was found to induce hypotension, to dilate arterial vessels, to exert negative ino- and chronotropic effects, to decrease... |
3043945 | [ERCP: which contrast medium is suitable?]. | To evaluate, wether a new non-ionic contrast medium decreases the complication rate of endoscopic retrograde cholangiopancreaticography (ERCP), we performed a prospective randomized study in 46 indoor patients with suspected pancreatic or bile duct related disease. The low-osmolar low-viscosity non-ionic Iopromid (Ultr... |
2840767 | Elastofibroma: an in vivo model of abnormal neoelastogenesis. | Thirteen cases of elastofibroma have been studied by conventional light and electron microscopy, as well as by histochemistry and immunohistochemistry. By light microscopy elastinophilic material appeared as huge fibers crossing collagen bundles. Immunohistochemistry demonstrated a strong positivity for elastin in nume... |
2455847 | The vasoinhibitory action of FR 46171, a new pyridine alcohol antianginal agent, on isolated rabbit vascular smooth muscles. | The vasoinhibitory effect of FR 46171, a new pyridine alcohol derivative, on contractile responses to alpha-adrenoceptor agonists was examined in isolated rabbit aorta. FR 46171 (10(-8)-10(-5) M) inhibited the maximum contractile response to clonidine (CL) in a concentration-dependent manner, but it only inhibited the ... |
3386636 | Classification and purification of proteins of heterogeneous nuclear ribonucleoprotein particles by RNA-binding specificities. | Several proteins of heterogeneous nuclear ribonucleoprotein (hnRNP) particles display very high binding affinities for different ribonucleotide homopolymers. The specificity of some of these proteins at high salt concentrations and in the presence of heparin allows for their rapid one-step purification from HeLa nucleo... |
2837734 | A DNA sequence outside the pUB110 minimal replicon is required for normal replication in Bacillus subtilis. | The origin of lagging strand synthesis in pUB110, oriL, has been localized within 140 bases outside the pUB110 minimal replicon. The oriL DNA sequence is a cis-acting and orientation dependent determinant required for normal plasmid replication. Rearrangements affecting oriL cause plasmid instability, lead to the accum... |
2967695 | Pharmacological profile of 8-amino octanoic acid substituted atrial natriuretic factor analogs. | A series of six analogs of rat atrial natriuretic factor have been prepared by the solid-phase method. The modified analogs contain 8-amino octanoic acid (a simple alkyl spacer) in place of selected tripeptides. Binding affinity to cultured aortic smooth muscle cell membranes suggests that the sequence Arg11-Gly16 is i... |
2836798 | The cloning, purification and characterization of the Eco RV modification methylase. | The gene for the Eco RV methylase has been cloned into a plasmid under control of the strong lambda PL promoter and overexpressed in E. coli. This plasmid, pVIC1, gives reliable overexpression of the methylase at levels of about 20% of total protein. Maximum yields of soluble protein are achieved after about 6 hours of... |
2453518 | Expression of simple epithelial type cytokeratins in stratified epithelia as detected by immunolocalization and hybridization in situ. | Multi-layered ("stratified") epithelia differ from one-layered ("simple") polar epithelia by various architectural and functional properties as well as by their cytoskeletal complements, notably a set of cytokeratins characteristic of stratified tissue. The simple epithelial cytokeratins 8 and 18 have so far not been d... |
3368787 | Inhibition of self-binding antibodies (autobodies) by a VH-derived peptide. | The self-binding properties of a dominant idiotypic antibody (T15) and a minor idiotypic antibody (M603), both specific for phosphorylcholine, were examined as models of self-binding antibodies (autobodies). Observed differences in the self-binding affinity of T15 and M603 relate to variable sequence differences in the... |
2897120 | Mechanochemical coupling in synthetic polypeptides by modulation of an inverse temperature transition. | For the polypentapeptide of elastin, (L-Val-L-Pro-Gly-L-Val-Gly)n, and appropriate analogs when suitably cross-linked, it has been previously demonstrated that development of elastomeric force at fixed length and length changes at fixed load occur as the result of an inverse temperature transition, with the temperature... |
2835768 | Structural analysis of a series of antiviral agents complexed with human rhinovirus 14. | The binding to human rhinovirus 14 of a series of eight antiviral agents that inhibit picornaviral uncoating after entry into host cells has been characterized crystallographically. All of these bind into the same hydrophobic pocket within the viral protein VP1 beta-barrel structure, although the orientation and positi... |
3364979 | Circular dichroism of bilirubin-amine association complexes: insights into bilirubin-albumin binding. | Bichromophoric (4Z, 15Z)-bilirubin-IX alpha, the yellow-orange cytotoxic pigment of jaundice, adopts either of two intramolecularly hydrogen-bonded enantiomeric conformations that are in dynamic equilibrium in solution. The addition of optically active amines induces the pigment solutions to exhibit intense bisignate c... |
3283937 | The design of molecular hosts, guests, and their complexes. | The origins, definitions, tools, and guiding principles of host-guest chemistry are developed. Perching, nesting, and capsular complexes are exemplified through molecular model and crystal structure comparisons. The degree of preorganization of a host for binding is a central determinant of its binding power. Complemen... |
2833611 | Localization and footprinting of an enhancer within the avian sarcoma virus gag gene. | A cis-acting regulatory element within the gag gene of avian retroviruses has been localized by deletion analysis, and sites of protein interaction have been studied by DNase I footprinting. Unidirectional deletions were made from both the 5' and 3' ends of a 656-base-pair fragment of the gag gene of Fujinami sarcoma v... |
3281909 | Heterogeneity among strains and a high rate of variation within strains of a major surface antigen of Mycoplasma pulmonis. | Monoclonal and monospecific antibodies were used to characterize a major Mycoplasma pulmonis surface antigen complex, V-1. Heterogeneity of V-1 was detected among strains and a high frequency of variation was detected within subclones of single strains. Analysis of 18 different strains showed that no two displayed iden... |
2895745 | Identification of a human erythrocyte receptor for colonization factor antigen I pili expressed by H10407 enterotoxigenic Escherichia coli. | We have identified a receptor for colonization factor antigen I (CFA/I) pili in human erythrocyte membranes. Erythrocyte binding assays, using whole organisms, suggested that the CFA/I receptor was a glycoprotein containing important sialic acid moieties. Subsequently, human erythrocyte membranes were extracted with li... |
3152567 | Contribution of antigen processing to the recognition of a synthetic peptide antigen by specific T cell hybridomas. | Most antigens recognized by T cells require unfolding or partial degradation (processing) followed by association with Major Histocompatibility Complex (MHC) molecules. We examined the processing requirements for the presentation of antigen to two T cell hybridomas which recognize the alpha-helical synthetic polypeptid... |
3273656 | Anhydroelastase: enhanced affinity toward product-type ligands revealed by affinity chromatography. | Anhydroelastase was effectively isolated by a single operation of affinity chromatography from a complex mixture produced by phenylmethylsulfonylation and alkaline treatment of porcine pancreatic elastase. The adsorbent used for the chromatography was 6-aminohexanoyl-trialanine, which corresponds to a product of elasta... |
3273655 | Estrogen receptor interaction with immobilized metals: differential molecular recognition of Zn2+, Cu2+ and Ni2+ and separation of receptor isoforms. | We have utilized iminodiacetate (IDA) gels with immobilized Zn2+, Cu2+ and Ni2+ ions to evaluate the metal binding properties of uterine estrogen receptor proteins. Soluble (cytosol) receptors labeled with [3H]estradiol were analyzed by immobilized metal affinity chromatography (IMAC) before as well as after (1) 3 M ur... |
3273654 | The design and synthesis of mimetics of peptide beta-turns. | The synthesis of an 11 membered ring bis-lactam, a system which is designed as a conformationally restricted mimetic of type I and type II beta-turns is described. Computer assisted molecular modeling was used to compare the predicted low energy conformers of the turn mimetic with idealized type I and type II turn stru... |
3273653 | Analysis and use of the serum albumin binding domains of streptococcal protein G. | Streptococcal protein G is an IgG-binding receptor with a molecular weight of 63 kDa as predicted from the sequence of the corresponding gene. Here we show that a truncated recombinant protein of 23 kDa still has IgG-binding capacity and also interacts specifically with human serum albumin (HSA). This demonstrates that... |
3273652 | Theoretical analysis of compartmented coupling in linear enzyme systems. | Exact equations which describe the kinetic patterns of enzyme/enzyme complexes, when compartmented coupling occurs between them, are presented. Compartmented coupling refers to the creation of a local environment in which the concentration of an intermediate, shared by two enzymes, is higher than its solution concentra... |
2483923 | Substance P synthesis by enzymatic fragment condensation using product-directed antibodies as molecular traps. | This paper describes the enzyme catalyzed synthesis of the undecapeptide substance P from its non-associated fragments (1-7) and (8-11) or (1-8) and (9-11). The fragment condensation was mediated by the use of product specific antibodies as molecular traps. As catalyst a previously purified endopeptidase was used which... |
2856032 | Sequence specific molecular recognition and binding of a monocationic bis-imidazole lexitropsin to the decadeoxyribonucleotide d-[(GATCCGTATG).(CATACGGATC)]: structural and dynamic aspects of intermolecular exchange studied by 1H-NMR. | The non-exchangeable and imino proton NMR resonances of the non self-complementary decadeoxyribonucleotide d-[(GATCCGTATG).(GATACGGATC)] as well as those of the 1:1 complex of the monocatonic bis-imidazole lexitropsin 1 to this sequence have been assigned by using a combination of NOE difference, COSY and NOESY techniq... |
3069195 | Methicillin-resistant staphylococci. | Strains of staphylococci resistant to methicillin were identified immediately after introduction of this drug. Methicillin-resistant strains have unusual properties, the most notable of which is extreme variability in expression of the resistance trait. The conditions associated with this heterogeneous expression of re... |
3199148 | Forces in molecular recognition: comparison of experimental data and molecular mechanics calculations. | NMR studies of the rotation barrier of the disaccharide of the glycopeptide antibiotic vancomycin have been used to test the performance of computer simulation techniques using molecular mechanics. In the absence of any solvated water, no correlation could be found between experiment and calculation. By introducing sol... |
3198059 | Epididymal sperm profiles in young adult, middle-aged, and testosterone-supplemented old rats. | Both ejaculated semen and epididymal contents from an individual male contain sperm that differ in various physicochemical characteristics. An experiment is reported in which epididymides from rats 5-24 months old were subjected to density gradient centrifugation to separate gametes of different stages of maturity. The... |
2842810 | Specificity within the GABAA receptor supramolecular complex: a consideration of the new omega 1-receptor selective imidazopyridine hypnotic zolpidem. | The relative contribution of different recognition sites within the GABAA receptor supramolecular complex (GRSC) to the pharmacological effects of anxiolytic and hypnotic drugs is unknown. The development of the omega 1 (ex BZ1) specific hypnotic zolpidem allows a more direct approach to the problem. In contrast to man... |
3042382 | The DNA invertase Gin of phage Mu: formation of a covalent complex with DNA via a phosphoserine at amino acid position 9. | The DNA invertase Gin encoded by bacteriophage Mu catalyses efficient site-specific recombination between inverted repeat sequences (IR) in vivo and in vitro in the presence of the host factor FIS and the recombinational enhancer. We demonstrate that Gin alone is able to introduce single strand breaks into duplex DNA f... |
2840947 | On the reaction of ferric heme proteins with nitrite and sulfite. | Optical and EPR spectroscopy of ferric heme proteins of the porphyrin, oxyporphyrin, and isobacteriochlorin classes has indicated that nitrite reacts with these proteins at the heme iron. Sulfite has been conclusively proven to react only with proteins containing the isobacteriochlorin macrocycle. Quantitative EPR spec... |
3393422 | Formation and antimicrobial activity of complexes of beta-cyclodextrin and some antimycotic imidazole derivatives. | Complex formation between beta-cyclodextrin and six antimycotic imidazole derivatives has been studied. The solubility of all drugs was increased in the presence of beta-cyclodextrin. The smallest increase (approx. 5-fold) was observed for miconazol, and the largest increase (approx. 160-fold) was observed for bifonazo... |
2838100 | Energetics of the actomyosin bond in the filament array of muscle fibers. | The interaction between actin and myosin in the filament array of glycerinated muscle fibers has been monitored using paramagnetic probes and mechanical measurements. Both fiber stiffness and the spectra of probes bound to a reactive sulfydral on the myosin head were measured as the actomyosin bond was weakened by addi... |
3382707 | Enhancement and simplification of macromolecular images. | Computer graphics programs have been devised to display selected atomic features and to simplify images of complex macromolecular structures. By using boundary outlines, adjustment of size and shape of the molecular components, color coding, shading, and selective omission of obscuring detail, attention can be focused ... |
3382625 | Melittin-induced changes of the macroscopic structure of phosphatidylethanolamines. | The binding of melittin to phosphatidylethanolamine model systems and its influence on the supramolecular organization of the lipid were investigated with binding assays, differential scanning calorimetry, 31P NMR, freeze-fracture electron microscopy, and small-angle X-ray scattering. The results are compared with bind... |
2454392 | Cloning of the human keratin 18 gene and its expression in nonepithelial mouse cells. | Human keratin 18 (K18) and the homologous mouse protein, Endo B, are intermediate filament subunits of the type I keratin class. Both are expressed in many simple epithelial cell types including trophoblasts, the first differentiated cell type to appear during mouse embryogenesis. The K18 gene was identified and cloned... |
2898098 | Double minute chromosomes can be produced from precursors derived from a chromosomal deletion. | Recent experiments have shown that gene amplification can be mediated by submicroscopic, autonomously replicating, circular extrachromosomal molecules. We refer to those molecules as episomes (S. Carroll, P. Gaudray, M. L. DeRose, J. F. Emery, J. L. Meinkoth, E. Nakkim, M. Subler, D. D. Von Hoff, and G. M. Wahl, Mol. C... |
2967858 | Determination of the catalytic activity of cyclomaltodextrin glucanotransferase by maltotriose-methylorange assay. | A kinetic assay of cyclomaltodextrin glucanotransferase (EC 2.4.1.19), based on the use of methylorange dye as the indicator of cyclodextrins, was studied and the reaction verified with independent HPLC analyses. The assay was optimized for the enzyme of an alkalophilic Bacillus sp. (ATCC 21783). Described enzymologica... |
2453837 | Selective recovery of foreign gene transcripts as virus-like particles in TMV-infected transgenic tobaccos. | A short origin-of-assembly sequence (OAS) located in the 30kDa movement protein gene, about 1.0kb from the 3'-end of the common strain of tobacco mosaic virus (TMV) RNA, nucleates encapsidation of the 6395-nucleotide-long genome by TMV coat protein in vitro, and presumably also in vivo. Single-stranded RNAs containing ... |
2836765 | Enhancement of Ia synaptic transmission following muscle nerve section: dependence upon protein synthesis. | Monosynaptic excitatory postsynaptic potentials (EPSPs) were recorded from the triceps surae motoneurons in the rat. Two to 3 weeks after section of the medial gastrocnemius (MG) nerve, Ia EPSPs evoked by stimulation of the MG nerve were significantly depressed, as reported previously. However, the MG EPSP amplitude si... |
3372731 | Ultrastructure of mouse vallate taste buds: III. Patterns of synaptic connectivity. | We have used serial high voltage electron micrographs and computer-generated, three-dimensional reconstructions to study morphological relationships and patterns of synaptic connectivity in taste buds from the circumvallate papillae of the mouse. The intragemmal arborizations of 40 sensory nerve fibers were examined fr... |
3366365 | Pronuclear fusion failure: an alternate conjugational pathway in Tetrahymena thermophila, induced by vinblastine. | Vinblastine is shown to induce pronuclear fusion failure in conjugating Tetrahymena thermophila. In this alternate conjugational pathway gametic pronuclei are exchanged between conjugants but do not fuse. Each pronucleus undergoes one mitotic division to produce a new macro- and micronucleus. Genetic consequences of pr... |
3360852 | Polymerization of actin by positively charged liposomes. | By cosedimentation, spectrofluorimetry, and electron microscopy, we have established that actin is induced to polymerize at low salt concentrations by positively charged liposomes. This polymerization occurs only at the surface of the liposomes, and thus monomers not in direct contact with the liposome remain monomeric... |
3283149 | Microtubule dynamics and chromosome motion visualized in living anaphase cells. | Chromosome segregation in most animal cells is brought about through two events: the movement of the chromosomes to the poles (anaphase A) and the movement of the poles away from each other (anaphase B). Essential to an understanding of the mechanism of mitosis is information on the relative movements of components of ... |
2833815 | The interplay between chemistry and biology in the design of enzymatic catalysts. | Chemists and biologists are focusing considerable effort on the development of efficient, highly selective catalysts for the synthesis or modification of complex molecules. Two approaches are described here, the generation of catalytic antibodies and hybrid enzymes, which exploit the binding and catalytic machinery of ... |
2451826 | Purification of an angiotensin II binding protein by using antibodies to a peptide encoded by angiotensin II complementary RNA. | We have generated a monospecific antibody to a synthetic peptide encoded by an RNA complementary to the mRNA for angiotensin II (AII) and determined whether this antibody recognizes the AII receptor. We demonstrate that the antibody competes specifically with 125I-labeled AII for the same binding site on rat adrenal me... |
2451823 | Sequence-specific recognition and cleavage of DNA by metallobleomycin: minor groove binding and possible interaction mode. | The DNase I cleavage-inhibition analysis shows binding sites of approximately 2 or 3 base pairs--in particular, 5' N-G-C sequences--for the green-colored CoIII and fully oxidized FeIII complexes of bleomycin. The apparent binding constant of the bleomycin-CoIII complex is quite similar for glucosylated and nonglucosyla... |
2833519 | Interactions between the microtubule-associated tau proteins and S100b regulate tau phosphorylation by the Ca2+/calmodulin-dependent protein kinase II. | Binding between the microtubule-associated tau protein and S100b protein was demonstrated by affinity chromatography and cross-linking experiments and was manifested in the effect of S100b on tau protein phosphorylation by protein kinase II. All three expressions of the binding showed that S100b discriminates among the... |
3356701 | Structural heterogeneity and purification of protein-free F430 from the cytoplasm of Methanobacterium thermoautotrophicum. | F430 is the nickel containing tetrapyrrole cofactor of S-methyl coenzyme M methylreductase, the enzyme that catalyzes the final step of methane production by methanogenic bacteria: the reduction of S-methyl coenzyme M (H3CSCH2CH2SO3-) to methane and coenzyme M (HSCH2CH2SO3-). The protein-free F430 obtained from the cyt... |
2895767 | Isolation and characterization of a receptor for type 1 fimbriae of Escherichia coli from guinea pig erythrocytes. | The adhesion of Escherichia coli to eukaryotic cells is mediated by proteinaceous surface appendages called fimbriae and complementary receptors on host cells. Although type 1 fimbriae, which contain a D-mannose-reactive lectin, have been well studied little is known about the binding mechanism of isolated fimbriae to ... |
2832845 | Illegitimate recombination mediated by calf thymus DNA topoisomerase II in vitro. | We have found that purified calf thymus DNA topoisomerase II mediates recombination between two phage lambda DNA molecules in an in vitro system. The enzyme mainly produced a linear monomer recombinant DNA that can be packaged in vitro. Novobiocin and anti-calf thymus DNA topoisomerase II antibody inhibit this ATP-depe... |
3353183 | Photophysical properties of Sn-porphyrins: potential clinical implications. | The photophysical properties of Sn-protoporphyrin and two of its synthetic analogues, Sn-mesoporphyrin and Sn-diiododeuteroporphyrin, were examined. All three compounds are potent competitive inhibitors of heme oxygenase, the rate-limiting enzyme in the catabolism of heme to bilirubin, and can suppress completely or di... |
2895103 | Structure and antigenic properties of the tip-located P pilus proteins of uropathogenic Escherichia coli. | Pyelonephritogenic Escherichia coli frequently expresses pili which bind to Gal alpha (1-4)Gal receptors present on the uroepithelium. Binding of these pili is mediated by a pilus-associated adhesin, PapG, and not by the major subunit which constitutes the bulk of the pilus structure. The adhesin and two pilinlike prot... |
2450871 | Structure and regulation of genes encoding phycocyanin and allophycocyanin from Anabaena variabilis ATCC 29413. | Gene clones encoding phycocyanin and allophycocyanin were isolated from an Anabaena variabilis ATCC 29413-Charon 30 library by using the phycocyanin (cpc) genes of Agmenellum quadruplicatum and the allophycocyanin (apc) genes of Cyanophora paradoxa as heterologous probes. The A. variabilis cpcA and cpcB genes occur tog... |
3127377 | New type of pullulanase from Bacillus stearothermophilus and molecular cloning and expression of the gene in Bacillus subtilis. | A new type of pullulanase which mainly produced panose from pullulan was found in Bacillus stearothermophilus and purified. The enzyme can hydrolyze pullulan efficiently and only hydrolyzes a small amount of starch. When pullulan was used as a substrate, the main product was panose and small amounts of glucose and malt... |
2831396 | Herpes simplex virus immunoglobulin G Fc receptor activity depends on a complex of two viral glycoproteins, gE and gI. | Evidence was recently presented that herpes simplex virus type 1 (HSV-1) immunoglobulin G (IgG) Fc receptors are composed of a complex containing a previously described glycoprotein, gE, and a novel virus-induced polypeptide, provisionally named g70 (D. C. Johnson and V. Feenstra, J. Virol. 61:2208-2216, 1987). Using a... |
18964512 | Preconcentration and voltammetric measurement of mercury with a crown-ether modified carbon-paste electrode. | Carbon-paste electrodes modified with crown-ethers were constructed by mixing the crown-ethers into a graphite powder/Nujol oil matrix. The electrodes so formed were able to bind mercuric ions chemically, and gave greater voltammetric response to mercury than that of ordinary carbon-paste electrodes. The response was c... |
3048692 | Prostaglandin I2 analogue and propranolol prevent ischaemia induced mitochondrial dysfunction through the stabilisation of lysosomal membranes. | Leakage of lysosomal enzymes is associated with irreversible cellular damage. To determine the effect of prostaglandin I2 analogue and propranolol on the ischaemic myocardium in relation to changes in lysosomal integrity 26 anaesthetised mongrel dogs were divided into three treatment groups and subjected to 2 h coronar... |
3390477 | [The role of topological limitations in the kinetics of homopolymer collapse and self-assembly of biopolymers]. | Fast collapse of a linear homopolymer after a spasmodic temperature decrease or deterioration of the solvent quality results in the initiation of folded nonequilibrium globule. The chain line in it is a fractal with the dimension mu less than or equal to 2 at small ranges and 3 at the large ones. This is provided by no... |
3390143 | Laminin biosynthesis in the extracellular matrix-producing cell line PFHR9 studied with monoclonal and polyclonal antibodies. | The biosynthesis of the basement-membrane glycoprotein laminin in the mouse teratocarcinoma cell line PFHR9 was studied by immunoelectron microscopy and pulse-chase experiments using monoclonal and polyclonal antibodies. By immunoelectron microscopy, most of the protein was found to be aggregated on the outer cell surf... |
2839145 | Consequences of molecular recognition in the S1-S2 intersubsite region of papain for catalytic-site chemistry. Change in pH-dependence characteristics and generation of an inverse solvent kinetic isotope effect by introduction of a P1-P2 amide bond into a two-protonic-state reactivity probe. | 1. The pH-dependences of the second-order rate constant (k) for the reactions of papain (EC 3.4.22.2) with 2-(acetamido)ethyl 2'-pyridyl disulphide and with ethyl 2-pyridyl disulphide and of k for the reaction of benzimidazol-2-ylmethanethiol (as a minimal model of cysteine proteinase catalytic sites) with the former d... |
3388760 | Adherence, spreading, and locomotion of bovine polymorphs: effect of proteins and metabolic inhibitors. | Adherence of bovine polymorphonuclear cells (PMN) on plastic, glass, and nylon wool fibers was assayed in the presence or in the absence of proteins and metabolic inhibitors. PMN adhered strongly and flattened on naked surfaces (without proteins). This process was active (did not occur at 5 degrees C), independent of d... |
3378035 | Actin-binding and dimerization domains of HeLa cell filamin. | HeLa cell filamin is a linear, bivalent, homodimer of high molecular weight subunits (Mr 250,000 that may cross-link actin filaments in vivo into supramolecular structures such as networks and bundles. We used millimolar Ca protease from chicken breast muscle to cleave the subunit into smaller fragments that we mapped ... |
3373427 | Utilization of diethyl-beta-cyclodextrin as a sustained-release carrier for isosorbide dinitrate. | Heptakis(2,6-di-O-ethyl)-beta-cyclodextrin (2) was prepared and its physicochemical properties, such as aqueous solubility and surface activity, were compared with those of beta-cyclodextrin (1) and heptakis(2,6-di-O-methyl)-beta-cyclodextrin (3). A possible utility of 2 as a sustained-release drug carrier was examined... |
3372640 | Simultaneous determination of C2-C22 non-esterified fatty acids and other metabolically relevant carboxylic acids in biological material by gas chromatography of their benzyl esters. | A method for the simultaneous determination of non-esterified short-, medium- and long-chain fatty acids and other types of metabolically relevant carboxylic acids such as hydroxy, keto, aromatic and dicarboxylic acids in biological material by capillary gas chromatography of benzyl ester derivatives is described. Samp... |
3285178 | Transforming growth factor alpha: mutation of aspartic acid 47 and leucine 48 results in different biological activities. | To study the relationship between the primary structure of transforming growth factor alpha (TGF-alpha) and some of its functional properties (competition with epidermal growth factor (EGF) for binding to the EGF receptor and induction of anchorage-independent growth), we introduced single amino acid mutations into the... |
2835666 | Autoregulated changes in stability of polyribosome-bound beta-tubulin mRNAs are specified by the first 13 translated nucleotides. | The expression of tubulin polypeptides in animal cells is controlled by an autoregulatory mechanism whereby increases in the tubulin subunit concentration result in rapid and specific degradation of tubulin mRNAs. We have now determined that the sequences that are necessary and sufficient to specify mouse beta-tubulin ... |
2835658 | Cloning of the RNA8 gene of Saccharomyces cerevisiae, detection of the RNA8 protein, and demonstration that it is essential for nuclear pre-mRNA splicing. | Strains of Saccharomyces cerevisiae that bear the temperature-sensitive mutation rna8-1 are defective in nuclear pre-mRNA splicing at the restrictive temperature (36 degrees C), suggesting that the RNA8 gene encodes a component of the splicing machinery. The RNA8 gene was cloned by complementation of the temperature-se... |
3367794 | Topographical specificity in isolated retinal capillary basement membranes: a high-resolution scanning electron microscope analysis. | Numerous investigations have demonstrated that basement membranes (BMs) are composed of type IV collagen, laminin, heparan sulfate proteoglycan, nidogen, and possibly fibronectin. The precise proportion and supramolecular organization of these molecules within BMs is unclear, but is believed to be tissue-specific. In a... |
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