id stringlengths 4 8 | title stringlengths 1 642 | abstract stringlengths 50 17.9k |
|---|---|---|
7028997 | Sulfated glycoproteins and extracellular matrix of cultured human pulmonary endothelial cells. | Endothelial cells derived from human pulmonary arteries incorporate (3H)-glucosamine and 35SO4 into glycosaminoglycans and into the carbohydrate side chains of glycoproteins. These 3H/35S-carbohydrate chains were isolated from cells and culture medium after Pronase digestion. The 3H/35S-glycosaminoglycans were separate... |
7299835 | Sperm-egg binding: identification of a species-specific sperm receptor from eggs of Stronglyocentrotus purpuratus. | We have attempted to identify a surface component of echinoderm eggs that is involved in the species-specific binding of sperm. Cell surface membranes from eggs of the sea urchins Strongylocentrotus purpuratus or Arbacia punctulata were radioiodinated, detergent-treated, and subjected to density-gradient centrifugation... |
6170757 | Monoclonal antibody (M2) to glial and neuronal cell surfaces. | A monoclonal antibody designated M2 arose from the fusion of mouse myeloma cells with splenocytes from a rat immunized with particulate fraction from early postnatal mouse cerebellum. Expression of M2 antigen was examined by indirect immunofluorescence on frozen sections of developing and adult mouse cerebellum and on ... |
7028996 | Protease-insensitive sea urchin embryo cell adhesions become protease sensitive in the presence of azide or cytochalasin B. | To understand the nature of the cell adhesions that must be modified during sea urchin embryo primary mesenchyme formation, we are studying the adhesive components of the hatched blastula stage embryo of Strongylocentrotus purpuratus. Pronase treatment conditions have been defined that leave the cells intact and able t... |
7028995 | Phenotypic diversification of a cultured tumor line as a function of substratum. | We have found that a murine hepatoma displays a considerable phenotypic diversification in culture, which depends upon the substratum utilized, and is manifested by the formation of multicellular structures of differing geometry: Monolayer on glass and plastic, thick multilayer pads on Gelfilm, and spheroids on agar an... |
7280057 | Possibility of genetic coding of amino acid sequences by coherent electronic states in nucleotide chains. | The concept of coherent electronic states and coherent interactions in supramolecular structures is applied to the process of genetic information coding and its transcription from DNA to mRNA. A new genetic code is proposed based on the assumption of coherent electron states in linear chains of nucleotide bases. A new ... |
7196830 | Structure of kinetochore fibers: microtubule continuity and inter-microtubule bridges. | To understand how microtubules interact in forming the mitotic apparatus and orienting and moving chromosomes, the precise arrangement of microtubules in kinetochore fibers in Chinese hamster ovary cells was examined. Individual microtubules were traced, using high voltage electron microscopy of serial 0.25 micron sect... |
7273115 | Catecholamines and 5-hydroxytryptamine in photophores of Porichthys notatus. Radioenzymatic detection and radioautographic localization. | Radioenzymatic assays and light microscope radioautographic studies performed on photophores of Porichthys notatus demonstrated (1) significant amounts of catecholamines (dopamine, noradrenaline, adrenaline) and 5-hydroxytryptamine (serotonin) in these organs; (2) selective uptake and storage of [3H]noradrenaline ([3H]... |
6974014 | Quasi-elastic light-scattering studies of single skeletal muscle fibers. | Measurements were made of the intensity autocorrelation function, g(2)[tau], of light scattered from intact frog muscle fibers. During the tension plateau of an isometric tenanus, scattered field statistics were approximately Gaussian and intensity fluctuations were quasi-stationary. The half time, tau 1/2, for the dec... |
6267317 | Transforming growth factors (TGFs): properties and possible mechanisms of action. | Transforming growth factors (TGFs) are growth-promoting polypeptides that cause phenotypic transformation and anchorage-independent growth of normal cells. They have been isolated from several human and animal carcinoma and sarcoma cells. One TGF is sarcoma growth factor (SGF) which is released by murine sarcoma virus-... |
6267316 | Multiplication stimulating activity (MSA) from the BRL 3A rat liver cell line: relation to human somatomedins and insulin. | The properties of multiplication stimulating activity (MSA), an insulin-like growth factor (somatomedin) purified from culture medium conditioned by the BRL 3A rat liver cell line are summarized. The relationship of MSA to somatomedins purified from human and rat plasma are considered. MSA appears to be the predominant... |
6267315 | Subcellular structures involved in internalization and degradation of epidermal growth factor. | Epidermal Growth Factor (EGF), a small polypeptide which acts as a mitogen for many cell types, has previously been shown to bind to a specific plasma membrane receptor on 3T3 cells. If 125I-EGF is bound to 3T3 cells for one hour at 4 degrees C, it remains predominantly associated with the plasma membrane-containing fr... |
6790719 | The effects of dipalmitoyl phosphatidyl choline on the precipitation of native fibrils and segment-long-spacing aggregates from collagen solution. | The effect of dipalmitoyl phosphatidyl choline (DPPC), the major phospholipid component of pulmonary surfactant, on the precipitation of collagen in the form of native fibrils and segment-long-spacing (SLS) aggregates was studied in vitro. The effects of DPPC on both phases of collagen fibrillogenesis were analyzed spe... |
6267314 | Spin label studies of erythrocytes with abnormal lipid composition: comparison of red cells in a hereditary hemolytic syndrome and lecithin: cholesterol acyltransferase deficiency. | Erythrocytes from patients with familial lecithin : cholesterol acyltransferase (LCAT) deficiency have been shown to exhibit an increase in membrane fluidity which is surprisingly small in view of the extensive alterations both in membrane lipid composition (namely, an elevation in cholesterol and phosphatidylcholine c... |
7257713 | Myelinated nerve fibers in the parathyroid gland of the dog: a light and electron-microscopic study. | The distribution of myelinated and non-myelinated nerve fibers in the parathyroid glands of the dog was studied by light and electron microscopy. The mixed fasciculi with myelinated nerve fibers (average diameter 7.0 micron) and unmyelinated fibers were present independent of the adventitia of the arterioles. The mixed... |
6166793 | Effect of heme on globin messenger RNA synthesis in spleen erythroid cells. | Synthesis of globin mRNA in erythroid spleen cells from anemic mice was measured after in vitro incubation under conditions in which the level of intracellular heme was manipulated. This newly synthesized globin mRNA was isolated by hybridization with globin cDNA covalently bound to cellulose. Isonicotinic acid hydrazi... |
6265706 | Alterations in growth requirements of kidney epithelial cells in defined medium associated with malignant transformation. | The possibility has been investigated that 1) the supplements required for the growth of the Madin Darby Canine Kidney (MDCK) cell line in serum-free Medium K-1 are indeed requirements for the growth of normal kidney cells in vitro, and 2) that alterations in these growth requirements are associated with malignant tran... |
7253649 | Cleavage of cell surface proteins by thrombin. | This study was based on our previous findings that the mitogenic action of thrombin on cultured fibroblasts can result from interaction of thrombin with the cell surface in the absence of internalization, and that the proteolytic activity of thrombin is required for stimulation of cell division. This prompted us to loo... |
7019575 | Stimulatory activity of PHA-LCM for normal human hemopoietic progenitors and leukemic blast cell precursors: separation by isoelectric focusing. | Medium conditioned by leukocytes in the presence of phytohemagglutinin (PHA-LCM) promotes growth of human hemopoietic progenitors (CFU-GEMM, BFU-E, CFU-C) and precursors of leukemic blast cells. PHA-LCM was separated by isoelectric focusing and each fraction tested with nonadherent cells of normal individuals as well a... |
6265705 | Interaction of serum and cell spreading affects the growth of neoplastic and non-neoplastic fibroblasts. | Both growth factor availability and cell-to-cell contact have been mechanisms used to explain cell growth regulation at high cell density. Recently Folkman and colleagues have shown that changes in cell shape, rather than cell-to-cell contact, can regulate the growth of fibroblasts. However, in those studies the relati... |
6265704 | Proteolytic domains of the epidermal growth factor receptor of human placenta. | Microsomal membranes form human placenta, which bind 5-20 pmol of 125I-epidermal growth factor (EGF) per mg protein, have been affinity-labeled with 125I-EGF either spontaneously or with dimethylsuberimidate. Coomassie blue staining patterns on SDS polyacrylamide gels are minimally altered, and the EGF-receptor complex... |
7019574 | Photoaffinity labeling of the insulin receptor in H4 hepatoma cells: lack of cellular receptor processing. | Photoaffinity labeling techniques were used to identify insulin-binding components of the plasma membrane in insulin-responsive, monolayer-cultured hepatoma cells. The activated, photosensitive reagent, an n-hydroxysuccinimide ester of 4-azidobenzoic acid, was coupled with highly purified insulin, and the hormone deriv... |
7248486 | Material self-assembly as a physicochemical process. | Material self-assembly as exemplified in protobiogeneses is shown to be result of molecular exchange interaction in reacting chemicals. Temporally and spatially correlated aggregates of reacting chemicals work as vertices of molecular exchange interaction. If the material accumulation rate at a locally correlated aggre... |
7018441 | Immunological and ultrastructural study of the surface of isolated rat testis germinal cells. | In the present study, cross absorption tests and indirect immunofluorescence detected antigenic differences between isolated testicular cell populations from 21 and 38 day old rats, respectively. Qualitatively, spermatids were the only cell type difference between these populations. Spermatozoa from adult rats were als... |
6264455 | Radioimmunoreactivity and receptor-binding activity of the recombined molecule obtained by complementation of two fibrinolysin fragments of ovine prolactin. | The recombined molecule obtained by complementation of two fibrinolysin fragments of ovine prolactin (oPRL) has been characterized by radioimmunoassay and radioreceptor assay. The recombinant alone exhibits very low radioimmunoreactivity and radioreceptor activity. However, in the presence of excess fragment oPRL-(1-53... |
6264434 | Biological reactivity of hypochlorous acid: implications for microbicidal mechanisms of leukocyte myeloperoxidase. | Oxidative degradation of biological substrates by hypochlorous acid has been examined under reaction conditions similar to those found in active phagosomes. Iron sulfur proteins are bleached extremely rapidly, followed in decreasing order by beta-carotene, nucleotides, porphyrins, and heme proteins. Enzymes containing ... |
6941238 | Complex of simian virus 40 large tumor antigen and 48,000-dalton host tumor antigen. | Simian virus 40 large tumor antigen (T Ag) can be separated by sucrose gradient sedimentation into a rapidly sedimenting, maximally phosphorylated fraction and a slowly sedimenting, less phosphorylated fraction. The Mr 48,000 host tumor antigen (48,000 HTA, also called nonviral T Ag) is preferentially complexed with th... |
6786384 | Possible causes for the calcification of glutaraldehyde-treated tissue heart valves and blood contacting elastomers during prolonged use in medical devices: a physico-chemical view. | Calcification of glutaraldehyde-treated porcine tissue heart valves (xenografts) is not a unique phenomenon but characteristic of a variety of synthetic elastomers and to a lesser extent of non-elastomeric polymers. The main commonality between them is their relative flexibility, permeability, and porosity, and differi... |
7013703 | Recovery of coliphages from wastewater effluents and polluted lake water by the magnetite-organic flocculation method. | A magnetite-organic flocculation method was developed for the concentration of coliphages from wastewater effluents and polluted lake water. A high percent (68 to 100%) recovery of coliphages from sewage effluents was achieved by this procedure. Coliphage recovery from Lake Alice, a sewage-contaminated lake, showed pha... |
7194522 | Organization of native and in vitro-reassembled myosin filaments from lobster tonic muscle. | Tonic muscle of the crusher claw of the American lobster (Homarus americanus) was investigated with respect to sarcomeric organization and the capacity for self-assembly of extracted myosin for comparison with the same properties of rabbit muscle. Native myosin filaments in the lobster muscle are much longer than in ra... |
6938991 | Biosynthesis of vitamin B12: mode of incorporation of factor III into cobyrinic acid. | Extensive chemical degradation of cobyrinic acid biosynthesized from a sample of factor III radiochemically labeled in its three methyl groups demonstrates that label is retained exclusively in the two methyl groups at positions C-2 and C-7 and confirms that the C-20 methyl group of the precursor is lost during formati... |
6938990 | Biosynthesis of vitamin B12: identity of fragment extruded during ring contraction to the corrin macrocycle. | Incorporation experiments with labeled sirohydrochlorin and trimethylisobacteriochlorin demonstrate that ring contraction in vivo to the corrin macrocycle of vitamin B12 liberates acetic acid. The C-20 atom of the precursors becomes the acetate carboxyl carbon. |
6938989 | Biosynthesis of vitamin B12: nature of the volatile fragment generated during formation of the corrin ring system. | It is shown with the help of radiolabeled substrates that biological formation of the corrin ligand system of cobyrinic acid is linked with the release of an equivalent of acetic acid from a hydroporphinoid precursor in which the C-20 atom has undergone methylation prior to its excision from the macrocycle. |
6260973 | Molecular genetics of herpes simplex virus. VII. Characterization of a temperature-sensitive mutant produced by in vitro mutagenesis and defective in DNA synthesis and accumulation of gamma polypeptides. | We report on the properties of a temperature-sensitive mutant produced by transfection of cells with intact DNA and a specific DNA fragment mutagenized with low levels of hydroxylamine. The plating efficiency of the mutant at 39 degrees C relative to that at 33.5 degrees C was 5 X 10(-6). The pattern of polypeptides pr... |
7217269 | Determination of barbiturates in mouse tissues by high-performance liquid chromatography. | Procedures for determining barbiturates in mouse tissues were investigated. High-performance liquid chromatography (HPLC) with mixtures of water and methanol as the mobile phase and muBondapak C18 as the stationary phase is superior to gas and thin-layer chromatography with respect to ease of sample preparation, accura... |
7213944 | The synthesis of some lipid-like structures in simulated primeval Earth conditions. | Starting from a simple gas mixture rich in methane, suggested as being a model of the primeval atmosphere for a certain time period, we succeeded in synthesizing lipid-like compounds. The hydrophobic nature of the products was demonstrated by IR, NMR, MS, elementary analysis, gel filtration measurements and solubility ... |
7193862 | Study of DNA films by the CD, X-ray and polarization microscopy techniques. | DNA films with psi +/- CD spectra have been investigated. X-ray analysis has shown the sign of the psi spectra to be independent of the secondary structure of DNA. The appearance of the psi spectra is attended by the formation of a characteristic polygonal texture of the cholesteric type in the DNA film. |
7193772 | [Granulocyte adherence and chemotaxis in children (author's transl)]. | Granulocyte adherence to endothelial surfaces associated with their chemotactic property enables these cells to leave the peripheral blood and to migrate into the tissue. This study was performed to investigate the effect of bacterial and viral infections as well as various kinds of therapies on these leukocyte functio... |
7193677 | Direct visualization of fluorescein-labeled microtubules in vitro and in microinjected fibroblasts. | Microtubule proteins and tubulin have been purified from brain and labeled with dichlorotriazinyl fluorescein (DTAF). This procedure compromises neither the polymerizability of the proteins nor their affinities for unlabeled proteins. Within 15 min after microinjection of either DTAF-microtubule proteins or DTAF-tubuli... |
7007327 | Effects of furazlocillin, a beta-lactam antibiotic which binds selectively to penicillin-binding protein 3, on Escherichia coli mutants deficient in other penicillin-binding proteins. | Furazlocillin binds selectively to penicillin-binding protein 3 (PBP-3), prevents septation of Escherichia coli, and allows the cells to form long filaments without lysis. The effect of furazlocillin on the morphology, autolysis, and murein synthesis of E. coli mutants deficient in either PBP-1A, PBP-1Bs, or PBP-2 was ... |
6161915 | Identity of the B56.5 protein, the A-protein, and the groE gene product of Escherichia coli. | Protein B56.5 is a major Escherichia coli protein, originally identified on two-dimensional gels as an abundant cellular protein with unique regulation. The groE gene product is a bacterial protein essential for the assembly of many diverse bacteriophages. The ribosomal A-protein is a large, acidic protein of unknown f... |
24301675 | Electrical membrane potential and resistance in photoautotrophic suspension cells of Chenopodium rubrum L. | On photoautotrophically grown, suspension-cultured cells of Chenopodium rubrum L. the electrical potential difference V mand the electrical resistance across plasmalemma and tonoplast have been measured using one or two intracellular micro-electrodes. In a mineral test-medium of 5.8 mM ionic strength V mvalues between ... |
16592945 | Mechanism of tobacco mosaic virus assembly: Incorporation of 4S and 20S protein at pH 7.0 and 20 degrees C. | The mechanism of assembly of tobacco mosaic virus (TMV) has been investigated at pH 7.0 and 20 degrees C by analytical ultracentrifugation. Under these conditions the overall rates of interconversion of 4S and 20S TMV coat protein are sufficiently slow to make possible measurements of the concentrations of remaining 4S... |
7169606 | Enhanced oral bioavailability of antiinflammatory drug flurbiprofen in rabbits by tri-O-methyl-beta-cyclodextrin complexation. | Inclusion complex of antiinflammatory drug flurbiprofen with tri-O-methyl-beta-cyclodextrin in 1:1 molar ratio was prepared, and its dissolution and absorption characteristics were compared with those of flurbiprofen. The apparent dissolution rate of flurbiprofen in water was significantly increased by the inclusion co... |
7165524 | [Functional morphology of neural elements in interorganic adhesions and in coalesced organs]. | The results of investigations concerning the problem on reinnervation of organs and vessels are summarized. Under the conditions of organo- and neuropexy, regenerating neural fibers pass through two stages of development. The first stage--formation and growth of neural fibers, the second--a more prolonged period of suc... |
6131095 | Supramolecular relationships of membrane antigens on the murine thymocyte. | The topographical relationships of Thy-1, Ly-1, Ly-2, and T200 were examined on the murine thymocyte. The inhibition of the binding of radiolabelled monoclonal antibody after incubation with unlabelled heterologous antibody was used as a measure of the proximity of the target antigens on the cell surface. On unfixed ce... |
6185952 | alpha-Amylase biosynthesis: signal sequence prevents normal conversion of the unprocessed precursor molecule to the biologically active form. | Recently, we showed that completion of the polypeptide chains on the polysomes isolated from germinating rice seed scutellum in a cell-free translation system can direct the synthesis of (i) unprocessed polypeptide containing the signal sequence (precursor 1), (ii) signal sequence-cleaved but nonglycosylated polypeptid... |
6218502 | Bacteriophage lambda int protein recognizes two classes of sequence in the phage att site: characterization of arm-type sites. | Purified int protein from bacteriophage lambda binds to specific sites in DNA that are not part of the functional attachment sites (non-att DNA) as well as to specific sites in att DNA. Analysis of non-att sites protected from nucleases by int has permitted definition of two distinctly different consensus recognition s... |
6961424 | Ultrastructure of the membrane attack complex of complement: detection of the tetramolecular C9-polymerizing complex C5b-8. | The ultrastructure of the membrane attack complex (MAC) of complement had been described as representing a hollow cylinder of defined dimensions that is composed of the proteins C5b, C6, C7, C8, and C9. After the characteristic cylindrical structure was identified as polymerized C9 [poly(C9)], the question arose as to ... |
7155898 | Nucleic acid binding properties of major proteins from the heterogeneous nuclear ribonucleoproteins of wheat. | Glycine-rich core hnRNP proteins purified from wheat bind tightly to single-stranded but not to double-stranded nucleic acids with a preference for natural RNA over single-stranded DNA. Binding results in i) a progressive disruption of the residual secondary structure of the polynucleotide and the formation of an exten... |
6897550 | Ca++-calmodulin-dependent phosphorylation of myosin, and its role in brush border contraction in vitro. | We have reinvestigated the effects of Ca++ and ATP on brush borders isolated from intestinal epithelial cells. At 37 degrees C, Ca++ (1 microM) and ATP cause a dramatic contraction of brush border terminal webs, not a retraction of microvilli as previously reported (M. S. Mooseker, 1976, J. Cell Biol. 71:417-433). Term... |
7153248 | Identification of a major polypeptide of the nuclear pore complex. | The nuclear pore complex is a prominent structural component of the nuclear envelope that appears to regulate nucleoplasmic molecular movement. Up to now, none of its polypeptides have been defined. To identify possible pore complex proteins, we fractionated rat liver nuclear envelopes and microsomal membranes with str... |
7153247 | Structure and polymerization of Acanthamoeba myosin-II filaments. | Acanthamoeba myosin-II forms filaments of two different sizes. Thin bipolar filaments 7 nm wide and 200 nm long consist of 16 myosin-II molecules. Thick bipolar filaments of variable width (14-19 nm) consist of 40 or more myosin-II molecules. Both have a central bare zone 90 nm long and myosin heads projecting laterall... |
7153246 | Binding of soluble type I collagen to fibroblasts: specificities for native collagen types, triple helical structure, telopeptides, propeptides, and cyanogen bromide-derived peptides. | Unlabeled collagenous proteins were quantified as inhibitors of binding of native, soluble, radioiodinated type I collagen to the fibroblast surface. Collagen types IV, V a minor cartilage isotype (1 alpha 2 alpha 3 alpha), and the collagenlike tail of acetylcholinesterase did not inhibit binding. Collagen types II and... |
6294338 | In vitro synthesis and assembly of picornaviral capsid intermediate structures. | Cell-free translation of encephalomyocarditis RNA in extracts of rabbit reticulocytes results in the synthesis of viral proteins indistinguishable from those produced during virus infection of cells. The viral capsid proteins are produced in an active form capable of assembly into viral capsid intermediate structures. ... |
7146904 | Mammalian muscle acetylcholine receptor: a supramolecular structure formed by four related proteins. | The nicotinic acetylcholine receptor has been purified from fetal calf muscle. Amino terminal amino acid sequence data indicate that the mammalian receptor is formed from closely related but distinct subunits. A cytoskeletal component, actin, may be associated with the receptor. |
7143046 | Characterization and localization of adenosine 3':5'-monophosphate-binding proteins in the nervous system of Aplysia. | Earlier work in Aplysia californica has indicated that sensitization of the gill reflex, a simple form of learning, is produced by cAMP-dependent protein phosphorylation which regulates the flux of ions in sensory neurons of the abdominal ganglion. These changes in ion flux result in the enhanced release of neurotransm... |
16346143 | Extracellular Isoamylase Produced by the Yeast Lipomyces kononenkoae. | A strain of the starch-converting yeast Lipomyces kononenkoae produced, when grown on starch, a debranching enzyme that proved to be an isoamylase (glycogen 6-glucanohydrolase; E.C. 3.2.1.68). So far, only bacteria have been found to produce extracellular isoamylases. The yeast isoamylase enhanced beta-amylolysis of am... |
7161546 | [A study of spinal evoked potentials recording from surface electrodes]. | With non-invasive method, spinal evoked potentials to the stimulation of the posterior tibial nerve at the ankle were studied in 20 normal subjects. Lumbosacral spinal evoked potentials, with a reference electrode on the contralateral shoulder or ear, demonstrated two well-defined negative peaks. The first peak origina... |
7154089 | Native bare zone assemblage nucleates myosin filament assembly. | Native myosin filaments from rabbit psoas muscle are always 1.5 micrometer long. The regulated assembly of these filaments is generally considered to occur by an initial antiparallel and subsequent parallel aggregation of identical myosin subunits. In this schema myosin filament length is controlled by either a self-as... |
6295516 | [Structural reconstruction of chemo-sensitive biomembranes during the action of low molecular weight compounds using spin resonance]. | Using the spin probe technique, the changes in the supramolecular structure of the central nervous system synaptic membranes and of olfactory hair membranes of Rana temporaria induced by low molecular weight organic substances of different chemical nature, were investigated. It was found that the membrane structures un... |
6294661 | Extensive intragenic sequence homology in two distinct rat lens gamma-crystallin cDNAs suggests duplications of a primordial gene. | The nucleotide sequences of two different rat lens gamma-crystallin cDNA clones, pRL gamma 2 and pRL gamma 3, have been determined. pRL gamma 3 contains the complete coding information for a gamma-crystallin of 173 amino acids whereas pRL gamma 2 is incomplete in that it lacks the codons for the first three amino acids... |
6960347 | Tubulin bound to colchicine forms polymers different from microtubules. | The purified tubulin-colchicine complex undergoes in vitro polymerization under the same conditions that promote the assembly of microtubules from purified tubulin. The need for a critical concentration, the apparent free energy change of the reaction, and the effects of divalent cations and nucleotide binding indicate... |
7175771 | Biochemical and structural analyses of microtubules in the pellicular membrane of Leishmania tropica. | The structure of the major protein of the pellicular membrane of Leishmania tropica was investigated. This protein is composed of two polypeptides, of ca. 50,000 d molecular weight, that were found to cross-react immunologically with the alpha and beta subunits of pig brain tubulin. The polypeptides and pig brain tubul... |
6128733 | Effects of taxol and Colcemid on myofibrillogenesis. | To determine the relationship between thin filaments, Z-bands, microtubules, intermediate filaments (IFs), T-tubules, and sarcoplasmic reticulum (SR) during myofibrillogenesis, myotubes were selectively depleted of their myofibrils with 12-tetradecanoylphorbol 13-acetate (TPA) and then were allowed to regenerate in (i)... |
6959131 | Subunit structure of the acetylcholine receptor from Electrophorus electricus. | The amino-terminal amino acid sequences of the four major peptides (Mr 41,000, 50,000, 55,000, and 62,000) present in purified preparations of Electrophorus electricus nicotinic acetylcholine receptor (AcChoR) have been determined for 24 cycles by automated sequence analysis procedures yielding four unique polypeptide ... |
6183278 | Domain and basement membrane specificity of a monoclonal antibody against chicken type IV collagen. | A monoclonal antibody, IV-IA8, generated against chicken type IV collagen has been characterized and shown to bind specifically to a conformational-dependent site within a major, triple helical domain of the type IV molecule. Immunohistochemical localization of the antigenic determinant with IV-IA8 revealed that the ba... |
7130392 | Molecular defect of spectrin in hereditary pyropoikilocytosis. Alterations in the trypsin-resistant domain involved in spectrin self-association. | In hereditary pyropoikilocytosis (HPP) the erythrocyte membrane skeleton exhibits mechanical instability that can be correlated to defective self-association of spectrin heterodimers. To detect structural changes in the functional domains of HPP spectrin we have examined the peptide pattern produced by limited tryptic ... |
7123255 | Artificial enzymes. | Simple chemical catalysts have been designed to achieve some desirable features of enzymes. These novel catalysts are not proteins, but they may incorporate the typical enzyme catalytic groups and they achieve selectivity in their reactions by use of geometric control, as do enzymes. Catalysts that carry out geometrica... |
16593253 | Evidence for a common ancestor sequence for the Balbiani ring 1 and Balbiani ring 2 genes in Chironomus tentans. | The Balbiani ring (BR) 1 and BR 2 genes in Chironomus tentans are functionally related and are only expressed in the salivary gland cells. Here we reveal the principal structure of the BR 1 gene and analyze the structural and evolutionary relationship between the BR 1 and BR 2 genes. The properties of the BR 1 gene, 37... |
6295263 | Effects of novobiocin, coumermycin A1, clorobiocin, and their analogs on Escherichia coli DNA gyrase and bacterial growth. | Novobiocin, coumermycin A1, and clorobiocin, structurally related compounds that antagonize the B subunit of the essential bacterial enzyme DNA gyrase, were compared with 18 of their analogs for the inhibition of Escherichia coli DNA gyrase supertwisting activity in vitro and of bacterial multiplication. This family of... |
7171575 | Conformational dynamics of the carboxylic ionophore lasalocid A underlying cation complexation-decomplexation and membrane transport. | The conformational dynamics of lasalocid A have been studied in a series of solvents of graded polarity by means of circular dichroism (CD) and computer-generated molecular models. In high polarity solvents, the uncomplexed anionic ionophore assumes as acyclic conformation minimizing intrinsic molecular strain energy. ... |
7149678 | [Production of 14-substituted derivatives of carminomycin and rubomycin]. | 14-Bromocarminomycin and 14-bromorubomycin were treated with alkali metal salts and nitrogen heterocycles to obtain 14-acetoxycarminomycin, 14-octamoylhydroxycarminomycin, 14-salicyloylhydroxycarminomycin, 14-salicyloylhydroxyrubomycin, 14-chinaldinoylhydroxyrubomycin and rubomycin 14-N-phthalimide, rubomycin 14-N-pyri... |
6292479 | Simian virus 40 large T antigen is phosphorylated at multiple sites clustered in two separate regions. | The phosphorylation sites of simian virus 40 large T antigen were determined within the primary structure of the molecule. Exhaustive digestion of (32)P-labeled large T antigen with trypsin generated six major phosphopeptides which could be separated in a newly developed isobutyric acid-containing chromatography system... |
6128384 | Effect of cyclodextrins on the acid hydrolysis of digoxin. | The effects of three cyclodextrins (alpha-, beta-, gamma-CyD) on the acid hydrolysis of digoxin were examined. From the high performance liquid chromatographic tracing of each of the four components (digoxin, bisdigitoxoside, monodigitoxoside, digoxigenin) in reaction mixtures, the individual rate constants (K1-K6) wer... |
6128383 | Mechanism of drug dissolution rate enhancement from beta-cyclodextrin-drug systems. | The influence of beta-cyclodextrin on the physicochemical properties of bendrofluazide, chlorothiazide, hydrochlorothiazide and hydroflumethiazide was investigated using solubility, X-ray powder diffraction, differential scanning calorimetry (DSC) and intrinsic dissolution rate methods. The solubility of each drug was ... |
7139310 | Rat optic nerve: freeze-fracture studies during development of myelinated axons. | This freeze-fracture study examines the development of myelinated fibers in the rat optic nerve. Axolemma of optic nerve fibers were studied before, during, and after myelination. At birth, the optic nerve is composed entirely of non-myelinated (premyelinated) axons, while in the adult, virtually all fibers acquire com... |
7139034 | Solvation properties of natural and synthetic ionophores. I. Stoichiometry of complexes with alkali and alkaline earth cations in aprotic organic solvents. | Ion-solvent interactions play a very important role in the studies of stoichiometry, structure, and stability of complexes of cations with natural and synthetic ionophores. These compounds are extremely useful in study of the interaction of neutral salts with macromolecules and the mechanism of cation transport across ... |
6956770 | beta-Cyclodextrin: promoting effect on the development of renal tubular cell tumors in rats treated with N-ethyl-N-hydroxyethylnitrosamine. | Injection (sc) of beta-cyclodextrin (beta-C) increased the number and size of renal tubular cell tumors in inbred Wistar (W) rats treated with 1,000 ppm of N-ethyl-N-hydroxyethylnitrosamine (EHEN). The incidence of renal tumors at the end of the 32-week experiment was 50% in rats treated with 1,000 ppm EHEN for 2 weeks... |
7119110 | Spectrin beta-chain variant associated with hereditary elliptocytosis. | An electrophoretically fast-moving variant of the spectrin beta-chain was discovered in the erythrocyte membranes of a woman and her father who both exhibited elliptocytosis and mild hemolytic anemia. This abnormal beta'-subunit (Mr = 214,000) co-existed with a decreased normal beta-chain and represented about half of ... |
6811561 | Murein components rescue developmental sporulation of Myxococcus xanthus. | Murein (peptidoglycan) components are able to rescue sporulation in certain sporulation-defective mutants of Myxococcus xanthus. N-Acetylglucosamine, N-acetylmuramic acid, diaminopimelic acid, and D-alanine each increase the number of spores produced by SpoC mutants. When all four components are included they have a sy... |
6288663 | Antagonism of the B subunit of DNA gyrase eliminates plasmids pBR322 and pMG110 from Escherichia coli. | The constructed plasmid pBR322 and the native plasmid pMG110 were eliminated (cured) from growing Escherichia coli cells by the antagonism of the B subunit of the bacterial enzyme DNA gyrase. The antagonism may be by the growth of cells (i) at semipermissive temperatures in a bacterial mutant containing a thermolabile ... |
7153847 | Cyclodextrin-induced hemolysis and shape changes of human erythrocytes in vitro. | Cyclodextrins (CyDs) at higher concentrations were found to cause hemolysis of human erythrocytes in the order of beta- greater than alpha- greater than gamma-CyD in isotonic solution. Biphasic effects of CyDs were observed for the osmotic and heat-induced hemolysis; i.e. the protection at relatively low CyD concentrat... |
7149276 | Intrinsic innervation of porcine semilunar heart valves. | In order to provide additional information on the morphology and the functional performance of semilunar valves, the presence of nerve fibers was investigated in the aortic and pulmonary leaflets by AChE techniques, formaldehyde-induced fluorescence methods, en block silver nitrate and gold chloride impregnation and el... |
6292464 | Simian virus 40 encapsidation: characterization of early intermediates. | Simian virus 40 chromosomes were separated into various species by a two-step purification consisting of low-ionic-strength glycerol gradient sedimentation followed by low-ionic-strength agarose gel electrophoresis. For each species of simian virus 40 chromosome purified, the comigrating DNA and proteins were identifie... |
7143565 | Isolation and genetic characterization of temperature-sensitive mutants of vaccinia virus WR. | One hundred temperature-sensitive mutants of vaccinia virus WR were isolated from virus that had been mutagenized with 5-bromodeoxyuridine or N-methyl-N'-nitro-N-nitrosoguanidine. A rapid screening procedure based on the ability of vaccinia virus to form plaques under liquid overlay medium was used to identify potentia... |
6291051 | Frozen tissue sections as an experimental system to reveal specific binding sites for the regulatory subunit of type II cAMP-dependent protein kinase in neurons. | Specific binding sites for the regulatory subunit of type II cAMP-dependent protein kinase (RII) were revealed in neurons by an immunohistochemical approach. Fixed frozen sections of several regions of the rat central nervous system were incubated in the presence of bovine RII. Bound bovine RII was subsequently detecte... |
7130275 | Membrane distribution in dividing endosperm cells of Haemanthus. | Membranes in cell-wall-free dividing endosperm cells of Haemanthus were examined after postfixation with osmium tetroxide-potassium ferrocyanide. We found that preservation and staining of membranes in metaphase cells was highly variable. Even adjacent cells often showed different degrees of preservation of membrane. H... |
6287846 | Production and characterization of a monoclonal antibody to human Type IV collagen. | We have produced a monoclonal antibody to human basement membrane Type IV collagen. The antibody reacts with the pepsin-resistant, collagenase-sensitive domain of Type IV collagen isolated from placental membranes, but not with human collagens of Types I, II, III, V, 1alpha, 2alpha, and 3alpha. The antibody precipitate... |
6125517 | Role of Mg2+ in the Ca2+-Ca2+ exchange mediated by the membrane-bound (Ca2+, Mg2+)-ATPase of sarcoplasmic reticulum vesicles. | Sarcoplasmic reticulum vesicles were preloaded with either 45Ca2+ or unlabeled Ca2+. The unidirectional Ca2+ efflux and influx, together with Ca2+-dependent ATP hydrolysis and phosphorylation of the membrane-bound (Ca2+, Mg2+)-ATPase, were determined in the presence of ATP and ADP. The Ca2+ efflux depended on ATP (or A... |
6179926 | Immunological characterization of Escherichia coli B glycogen synthase and branching enzyme and comparison with enzymes from other bacteria. | Escherichia coli B glycogen synthase and branching enzyme, although similar in amino acid composition, had no significant immunological cross-reactivity. The N-terminal sequences of the glycogen synthase were rich in hydrophobic residues, whereas branching enzyme had a higher content of acidic and basic residues. Howev... |
6814426 | The process for the activation of frog epidermis pro-tyrosinase. | 1. Purified pro-tyrosinase from epidermis of the frog Rana esculenta ridibunda can be activated in vitro by several proteinases (trypsin, alpha-chymotrypsin, Pronase) and by light. 2. Both pro-tyrosinase and tyrosinase are composed of a single type of subunit having pI 7.2 and approximate molecular weights 68000 and 62... |
6812059 | Cooperative effects in water-biomolecule crystal systems. | Monte Carlo computer simulation techniques have been used to model non-pair-additive (cooperative) effects in the water organization around several biomolecules. Although most models for water assume pair-additive potentials, both quantum mechanical calculations and experimental data indicate that cooperative effects a... |
6956899 | Regulated expression of an extrachromosomal human beta-interferon gene in mouse cells. | Beta(fibroblast)-interferon mRNA and protein are induced by the synthetic double-stranded RNA poly(I) X poly(C) in cultured human fibroblasts. To study the mechanism of this induction, we have isolated a human beta-interferon gene and inserted it in a vector plasmid containing DNA of the bovine papilloma virus. After r... |
6812056 | Modulation of mRNA for microtubule-associated proteins during brain development. | The heterogeneity of tau microtubule-associated proteins from rat brain is developmentally determined. Newborn rat brain contains two tau polypeptides (tau 0) with somewhat different molecular weights than the five tau components associated with microtubules from 12-day-old brain (tau 12). tau 0 and tau 12 are immunolo... |
6750355 | The role of chlorophyll-protein complexes in the function and structure of chloroplast thylakoids. | The photosynthetic pigments of chloroplast thylakoid membranes are complexed with specific intrinsic polypeptides which are included in three supramolecular complexes, photosystem I complex, photosystem II complex and the light-harvesting complex. There is marked lateral heterogeneity in the distribution of these compl... |
6288566 | Binding characteristics of wild mouse type C virus to mouse spinal cord and spleen cells. | Binding characteristics of mouse spinal cord and spleen cells to naturally occurring, ecotropic (paralytogenic and lymphomagenic 1504M virus) and amphotropic (lymphomagenic 1504A virus) retroviruses of wild mice were investigated. 125I-labeled ecotropic (N-tropic) virus bound efficiently to both spinal cord and spleen ... |
6288134 | Three-dimensional disorder of dipolar probes in a helical array. Application to muscle cross-bridges. | Fluorescence polarization and EPR experiments on azimuthally randomized helices bearing extrinsic (dipolar) probes yield information about the axial orientation and order of the probes. If the orientation of the probe on the structure bearing it is known and disorder is absent, the orientation of the structure may be a... |
7109039 | Evidence for an internal component of the bacteriophage T4D tail core: a possible length-determining template. | The length of the T4 tail is precisely regulated in vivo at the time of polymerization of the tail core protein onto the baseplate. Since no mutations which alter tail length have been identified, a study of in vivo-assembled tail cores was begun to determine whether the structural properties of assembled cores would r... |
7202011 | Hydrodynamic models of viscous coupling between motile myosin and endoplasm in characean algae. | Cytoplasmic streaming in characean algae is thought to be driven by interaction between stationary subcortical actin bundles and motile endoplasmic myosin. Implicit in this mechanism is a requirement for some form of coupling to transfer motive force from the moving myosin to the endoplasm. Three models of viscous coup... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.