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8327511 | Negatively charged amino acid residues in the nicotinic receptor delta subunit that contribute to the binding of acetylcholine. | In nicotinic receptors, the binding sites for acetylcholine are likely to contain negatively charged amino acid side chains that interact with the positively charged quaternary ammonium group of acetylcholine and of other potent agonists. We previously found that a 61-residue segment of the delta subunit contains aspar... |
8327467 | A kinetic model for amyloid formation in the prion diseases: importance of seeding. | The transmissible spongiform encephalopathies (TSEs) are neurodegenerative diseases characterized by amyloid formation in the brain. The major amyloid protein is the prion protein (PrP). PrP and the beta-amyloid protein of Alzheimer disease share a similar sequence that, in both cases, may be responsible for the initia... |
8325879 | Structure of mouse Mx1 protein. Molecular assembly and GTP-dependent conformational change. | Mouse Mx1 protein is an interferon-inducible nuclear protein and confers resistance to influenza virus infection. The Mx1 protein purified from interferon-induced A2G mouse liver exhibited GTPase activity as did the Mx1 protein purified from the Mx1 cDNA-expressing Escherichia coli (Nakayama, M., Nagata, K., Kato, A., ... |
8325394 | Retention of native-like structure in an acyclic counterpart of a beta-sheet antibiotic. | An acyclic derivative of the cyclic peptide antibiotic, ramoplanin, has been prepared. In aqueous solution, two-dimensional NMR spectroscopy indicates that the acyclic form adopts a threshold population of conformers in which at least part of the beta-sheet characteristic of the intact ramoplanin persists. Thus, despit... |
8323954 | Structure and composition of type IV collagen of bovine aorta. | To determine the chain composition of type IV collagen of bovine thoracic aorta, we analyzed collagenase-solubilized carboxyl-terminal noncollagenous (NC1)-domains by high-pressure liquid chromatography, two-dimensional electrophoresis, immunoblotting and enzyme-linked immunoassay. In addition to the classical alpha 1-... |
8321236 | The fission yeast ferric reductase gene frp1+ is required for ferric iron uptake and encodes a protein that is homologous to the gp91-phox subunit of the human NADPH phagocyte oxidoreductase. | We have identified a cell surface ferric reductase activity in the fission yeast Schizosaccharomyces pombe. A mutant strain deficient in this activity was also deficient in ferric iron uptake, while ferrous iron uptake was not impaired. Therefore, reduction is a required step in cellular ferric iron acquisition. We hav... |
8321233 | Identification and characterization of a beta-globin promoter-binding factor from murine erythroleukemia cells. | We have identified a DNA-binding activity with specificity for the beta DRE, an evolutionarily conserved transcriptional regulatory element in mammalian adult beta-globin promoters. This binding activity, which we term beta DRf, for beta-globin direct repeat factor, was detected in fractionated nuclear extracts from th... |
8320262 | The roles of the rod end and the tail in vimentin IF assembly and IF network formation. | Using mutagenesis, we investigated the importance of two vimentin domains: (a) a highly conserved segment near the carboxy end of the alpha-helical rod, and (b) the tail, with which the rod end is known to interact. As judged by in vitro filament assembly and expression in transiently transfected cells lacking an endog... |
8391536 | Stepwise reassembly of the nuclear envelope at the end of mitosis. | The nuclear envelope consists of three distinct membrane domains: the outer membrane with the bound ribosomes, the inner membrane with the bound lamina, and the pore membrane with the bound pore complexes. Using biochemical and morphological methods, we observed that the nuclear membranes of HeLa cells undergoing mitos... |
8320230 | In vivo and in vitro studies of a copy number mutation of the RepA replication protein of plasmid pSC101. | The RepA replication protein of plasmid pSC101 binds as a monomer to three repeated sequences (RS1, RS2, and RS3) in the replication origin of the plasmid to initiate duplication and binds as a dimer to two inversely repeated sequences (IR1 and IR2) in its promoter region (D. Manen, L. C. Upegui-Gonzalez, and L. Caro, ... |
8391534 | Anabaena sp. strain PCC 7120 bifA gene encoding a sequence-specific DNA-binding protein cloned by in vivo transcriptional interference selection. | VF1 is a DNA-binding protein from the cyanobacterium Anabaena sp. strain PCC 7120. VF1 was originally identified on the basis of its binding affinity to the upstream region of xisA, which encodes a heterocyst-specific site-specific recombinase. VF1 also binds to the glnA, rbcL, and nifH promoters in vitro, suggesting t... |
8320218 | Regulatory interactions between RepA, an essential replication protein, and the DNA repeats of RepFIB from plasmid P307. | The control of RepFIB replication appears to rely on the interaction between an initiator protein (RepA) and two sets of DNA repeat elements located on either side of the repA gene (BCDD'D" and EFGHIJ). In vivo genetic tests demonstrate that the BCDD'D" repeats form part of the origin of replication, while some of the ... |
8318518 | The unusual light-harvesting complex of Mantoniella squamata: supramolecular composition and assembly. | The supramolecular properties of the chlorophyll a/b/c light-harvesting protein complex of Mantoniella squamata were analyzed. The complex is built up of at least two subunits of M(r) 20,000 and 22,000, which are encoded in the nucleus as precursor proteins of M(r) 27,000. The chlorophyll a/b/c light-harvesting complex... |
8391001 | Albumin inhibits neutrophil spreading and hydrogen peroxide release by blocking the shedding of CD43 (sialophorin, leukosialin). | Spreading of neutrophils on protein-coated surfaces is a pivotal event in their ability to respond to soluble, physiologic agonists by releasing large amounts of hydrolases and oxidants. Using neutrophils plated on serum-, fibrinogen- or fibronectin-coated surfaces, we investigated the effect of human serum albumin (HS... |
7685413 | trans processing of vaccinia virus core proteins. | The three major vaccinia virus (VV) virion proteins (4a, 4b, and 25K) are proteolytically matured from larger precursors (P4a, P4b, and P25K) during virus assembly. Within the precursors, Ala-Gly-X motifs have been noted at the putative processing sites, with cleavage apparently taking place between the Gly and X resid... |
7685408 | Immunization of mice with vaccinia virus-M2 recombinant induces epitope-specific and cross-reactive Kd-restricted CD8+ cytotoxic T cells. | The M2 protein of respiratory syncytial virus (RSV) is a protective antigen in H-2d, but not H-2b or H-2k mice. None of the other RSV proteins, excluding the surface glycoproteins that induce neutralizing antibodies, is protective in mice bearing these haplotypes. Thus, the M2 protein stands alone as a nonglycoprotein-... |
8389910 | The PU.1/Spi-1 proto-oncogene is a transcriptional regulator of a lentivirus promoter. | The enhancer unit present in the retrovirus equine infectious anemia virus (EIAV) was previously shown to contain binding sites for proteins belonging to MDBP, PEA2, AP-1, and ets families. The EIAV ets motif matches the consensus sequence for both PEA3- and PU.1-binding sites. Here, we show by gel shift analysis that ... |
24227646 | Applications of electrospray ionization mass spectrometry to neutral organic molecules including fullerenes. | The use of electrospray ionization mass spectrometry (ESI/MS) for the detection of neutral organic molecules becomes possible by their derivation with specific ESI/MS tagging reagents that have either proton or metal ion binding sites. We used the neutral crown ether group in several reagents to attach a metal binding ... |
22556632 | A review on licorice. | Licorice (Glycyrrhizaglabra L) is an important herb used in almost all systems of medicine. The author tries to present in this article a comprehensive review on all aspects of Licorice. |
18965752 | Spectrophotometric determination of trace copper with a Cu-diethyldithiocarbamate-beta-cyclodextrin colour system. | A simple, selective and accurate spectrophotometric method for determination of trace copper with diethyldithiocarbamate(DDTC) in the presence of beta-cyclodextrin(beta-CD) in ammonia media has been developed. The apparent molar absorptivity of Cu(II)-DDTC-beta-CD inclusion complex is 1.3 x 10(4) 1 . mole(-1) . cm(-1) ... |
15278812 | Metabolic changes associated with malnutrition in the patients with multiple organ failure. | To clarify the metabolic changes associated with malnutrition in the patients with multiple organ failure (MOF), we measured energy expenditure, nitrogen excretion, nonprotein respiratory quotient (NPRQ), caloric intake, and cumulative caloric balance (CCB) in 20 MOF patients (12 survivors and 8 non-survivors). The non... |
11607406 | Calvin cycle multienzyme complexes are bound to chloroplast thylakoid membranes of higher plants in situ. | Further evidence is provided that the Calvin cycle enzymes ribose-5-phosphate isomerase (EC 5.3.1.6), ribulose-5-phosphate kinase (Ru-5-P-K, EC 2.7.1.19), ribulose-1,5-bisphosphate carboxylase (RuP2Case, EC 4.1.1.39), glyceraldehyde-3-phosphate dehydrogenase (GAPDH, EC 1.2.1.12), sedoheptulose-1,7-bisphosphatase (Sed-1... |
11607405 | Self-recognition in helicate self-assembly: spontaneous formation of helical metal complexes from mixtures of ligands and metal ions. | On treatment with copper(I) ions, mixtures of the [oligo(2,2')-bipyridine] strands 2-5 yield spontaneously the double helicates 2H(2)-2H(5) without significant crossover. Similarly, when a mixture of the two tris-bypyridine ligands 1 and 3a (containing different substitutions) is allowed to react with copper(I) and nic... |
8305253 | Chymotrypsin inhibitory conformation of dipeptides constructed by side chain-side chain hydrophobic interactions. | A complete series of configurational isomers (L-L, L-D, D-L and D-D) of a dipeptide Leu-Phe benzyl ester have been synthesized and assayed for chymotrypsin. In the conformational analysis by 400 MHz 1H NMR, the L-D and D-L isomers, but not the L-L and D-D isomers, showed fairly large upfield shifts (0.2-0.4 ppm) of Leu... |
7508238 | Peptide vaccines incorporating a 'promiscuous' T-cell epitope bypass certain haplotype restricted immune responses and provide broad spectrum immunogenicity. | An ideal peptide vaccine should contain both B- and T-cell epitopes. Recognition of antigen by B cells is highly dependent on the three-dimensional conformation of the antigen whereas T cells recognize antigen only after it has been processed to release a peptide fragment which is bound to the major histocompatibility ... |
7508237 | Epitope analysis using kinetic measurements of antibody binding to synthetic peptides presenting single amino acid substitutions. | The fine modulation of peptide-antibody interactions was investigated with anti-peptide monoclonal antibodies recognizing peptide 125-136 of the coat protein of tobacco mosaic virus. Nine synthetic peptides presenting single amino acid substitutions were selected for detailed analysis on the basis of their reactivity i... |
8305252 | MHC class I/peptide interactions: binding specificity and kinetics. | Recent developments in the preparation of soluble analogues of the major histocompatibility complex (MHC) class I molecules as well as in the application of real time biosensor technology have permitted the direct analysis of the binding of MHC class I molecules to antigenic peptides. Using synthetic peptide analogues ... |
8305251 | Kinetic measurements of molecular interactions by spectrofluorometry. | The kinetics of antibody-antigen interactions are reviewed in terms of general trends observed in both polyclonal and monoclonal antibody populations. Anti-fluorescein antibodies are featured in the review as model proteins to explore fluorescence-based kinetic measurements. Since the fluorescence of the fluorescein li... |
8221993 | [Ultrastructural changes in endothelial cells in rabbits with multiple organ failure (MOF)]. | The morphological lesions of endothelial cells in rabbits with MOF were studied by scanning (SEM) and transmission electron microscopy (TME). The edges of the cells were blurred in the MOF groups. TEM showed that the nuclei were irregular and the mitochondria were swollen. The results indicated that the vascular endoth... |
8405370 | Interaction of mutagenic tryptophan pyrolysate with DNA. CD spectral study on the binding specificity. | The interactions of DNA duplexes with 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), a potent mutacarcinogen isolated from tryptophan pyrolysate, have been studied using CD spectroscopy. The results are that (a) the spectral change of B-form DNA caused by the interaction with Trp-P-1 is biphasic, i.e. the enlar... |
8399520 | 2',3'-dideoxyinosine (ddI): its chemical stability and cyclodextrin complexation in aqueous media. | The chemical stability of 2',3'-dideoxyinosine has been studied over a wide pH range (0-12). A stability-indicating HPLC method was used to separate the degradation product from the parent drug. The effects of temperature, ionic strength and buffer components on the degradation kinetics were investigated. Furthermore, ... |
8396570 | Preparation and optical characteristics of hemoglobin-free isolated perfused rat head in situ. | Using a new cannulation method, which completely prevented interruption of circulation to brain tissue during surgical operations, we could prepare a functionally intact hemoglobin-free isolated perfused rat head in situ. The frequency distribution (8-25 Hz) and amplitude of a spontaneous electroencephalogram, EEG (50 ... |
8369624 | Structure of nicotinic acetylcholine receptors. | Nicotinic acetylcholine (ACh) receptors convert the binding of ACh into the opening of a cation-conducting channel. New information about the regions of the receptor most immediately involved in its function, namely the ACh-binding sites, the gate and the channel, has come from two approaches. One is the identification... |
8396449 | Saturation transfer electron parametric resonance of an indane-dione spin-label. Calibration with hemoglobin and application to myosin rotational dynamics. | We have used a recently synthesized indane-dione spin label (2-[-oxyl-2,2,5,5-tetramethyl-3-pyrrolin-3-yl)methenyl]in dane-1,3-dione (InVSL) to study the rotational dynamics of myosin, with saturation-transfer electron paramagnetic resonance (ST-EPR). To determine effective rotational correlation times (tau effr) from ... |
8358552 | Roles of prostacyclin, EDRF and active oxygens in leukocyte-dependent platelet adhesion to endothelial cells induced by platelet-activating factor in vitro. | 1. The mechanism of polymorphonuclear leukocyte (PMN)-dependent platelet adhesion to cultured endothelial cells induced by platelet-activating factor (PAF) was investigated to determine whether PMNs release or generate any factor(s) capable of inducing platelet adhesion, and the roles of prostacyclin and endothelium-de... |
8355145 | [Development and pharmaceutical evaluation of hydrophobic cyclodextrin derivatives as modified-release drug carriers]. | Hydrophobic cyclodextrin (CyD) derivatives, such as 2,6-di-O-ethyl-beta-CyD (DE-beta-CyD), 2,3,6-tri-O-ethyl-beta-CyD (TE-beta-CyD), carboxymethylethyl-beta-CyDs (CME-beta-CyDs) with different degrees of substitution, 2,3,6-tri-O-acyl-beta-CyDs with different alkyl chains (C1-C12) were prepared and their chemical struc... |
8394110 | Molecular recognition using a binary genetic search algorithm. | A genetic algorithm has been devised and applied to the problems of molecular similarity, pharmacophore elucidation, and determination of molecular conformation. The algorithm is based on a binary representation of molecular position and conformation. Using the genetic operators, crossover, mutation, and selection near... |
8336675 | Biology, ecology, and biotechnological applications of anaerobic bacteria adapted to environmental stresses in temperature, pH, salinity, or substrates. | Anaerobic bacteria include diverse species that can grow at environmental extremes of temperature, pH, salinity, substrate toxicity, or available free energy. The first evolved archaebacterial and eubacterial species appear to have been anaerobes adapted to high temperatures. Thermoanaerobes and their stable enzymes ha... |
7687738 | Micrasterias cells as a model system for research on morphogenesis. | Micrasterias species have been the subject of numerous experimental studies on cell shape formation in the last 40 years. Chemical and physical treatment during different developmental stages, as well as investigations of ultrastructure by means of various different preparation methods, have yielded information about s... |
8335710 | Separation and determination of warfarin enantiomers in human plasma samples by capillary zone electrophoresis using a methylated beta-cyclodextrin-containing electrolyte. | A methyl beta-cyclodextrin with a degree of substitution of 1.8 proved to be an effective chiral selector, among other cyclodextrins tested, for the separation of warfarin enantiomers by capillary electrophoresis. The operating conditions were optimized with respect to electrolyte composition (buffer pH, ionic strength... |
8332495 | Cytoplasmic expression of a reporter gene by co-delivery of T7 RNA polymerase and T7 promoter sequence with cationic liposomes. | Expression of bacteriophage T7 RNA polymerase in mammalian cells can efficiently drive the transcription of a foreign gene controlled by the T7 promoter (Elroy-Stein et al., Proc. Natl. Acad. Sci. USA. 86, 6126-6130, 1989). We have tested the hypothesis that purified T7 RNA polymerase can be co-delivered into mammalian... |
8332470 | Activation of a dual adenovirus promoter containing nonconsensus TATA motifs in Schizosaccharomyces pombe: role of TATA sequences in the efficiency of transcription. | The role of TATA elements in the expression of a mammalian promoter was investigated in the fission yeast Schizosaccharomyces pombe, by studying the human adenovirus E2-early promoter. This is a unique dual promoter with two nonconsensus TATA elements directing transcription from two cap sites, +1 and -26. A sequence T... |
8328773 | Distribution of mec regulator genes in methicillin-resistant Staphylococcus clinical strains. | The distributions of the mec regulator genes mecI and mecR1, which were identified on the chromosome of mecA-carrying Staphylococcus aureus N315, in methicillin-resistant staphylococci isolated in Japan and various countries were studied. Screening by dot blot hybridization by using polymerase chain reaction (PCR)-ampl... |
8323397 | Microfibrillar elements in the synovial joint: presence of type VI collagen and fibrillin-containing microfibrils. | <h4>Objectives</h4>The aims were to isolate and positively identify the microfibrillar elements which have been observed in the synovial lining. In addition, synovial fluid was examined for these elements to improve the understanding of the role of these structures in health and disease.<h4>Methods</h4>Bacterial collag... |
8320797 | [The effects of two and five percent aqueous phenol on the cat tibial nerve in situ--II: Effect on the circulation of the tibial nerve]. | The previous report of ours showed that the biphasic depression of the compound action potentials in cat tibial nerve was observed after administration of 2% aqueous phenol, and the delayed depression was considered to be the result of the ischemia of the nerve fibers caused by the vascular damage with phenol. This sec... |
8319688 | Expression and mutation of soybean beta-amylase in Escherichia coli. | The cDNA clones corresponding to soybean beta-amylase mRNA were isolated and sequenced. The cDNA contained an open-reading frame composed of 496 amino acids. The comparison of the amino acid sequence deduced from the cDNA with the N-terminal peptide sequence from mature enzyme proved that beta-amylase had no leader seq... |
8319679 | Hydrogen-bonding pattern of methyl beta-lactoside binding to the Ricinus communis lectins. | The binding of O-methyl and fluorodeoxy derivatives of methyl beta-lactoside to the Ricinus communis toxin (RCA60) and agglutinin (RCA120) was studied in order to determine the donor/acceptor relationships of the hydrogen bonds between the hydroxyl groups of methyl beta-lactoside and the binding sites of the lectins. F... |
8318902 | Disulfide bonds in homo- and heterodimers of EF-hand subdomains of calbindin D9k: stability, calcium binding, and NMR studies. | The effect of decreased protein flexibility on the stability and calcium binding properties of calbindin D9k has been addressed in studies of a disulfide bridged calbindin D9k mutant, denoted (L39C + P43M + I73C), with substitutions Leu 39-->Cys, Ile 73-->Cys, and Pro 43-->Met. Backbone 1H NMR assignments show that the... |
8391357 | ATP binding to cytochrome c diminishes electron flow in the mitochondrial respiratory pathway. | Eukaryotic cytochrome c possesses an ATP-binding site of substantial specificity and high affinity that is conserved between highly divergent species and which includes the invariant residue arginine91. Such evolutionary conservatism strongly suggests a physiological role for ATP binding that demands further investigat... |
8318896 | Brownian dynamics simulations of molecular recognition in an antibody-antigen system. | The crystal structure for an antibody-antigen system, that of the anti-hen egg lysozyme monoclonal antibody HyHEL-5 complexed to lysozyme, is used as the starting point for computer simulations of diffusional encounters between the two proteins. The investigation consists of two parts: first, the linearized Poisson-Bol... |
8318886 | In vivo formation of active aspartate transcarbamoylase from complementing fragments of the catalytic polypeptide chains. | Despite the complexity of Escherichia coli aspartate transcarbamoylase (ATCase), composed of 12 polypeptide chains organized as two catalytic (C) trimers and three regulatory (R) dimers, it is possible to form active stable enzyme in vivo even with fragmented catalytic (c) chains. Based on the observation that chymotry... |
8391025 | Subclass-specific serum antibody responses to recombinant Norwalk virus capsid antigen (rNV) in adults infected with Norwalk, Snow Mountain, or Hawaii virus. | Subclass-specific antibody responses to the Norwalk virus capsid protein in adults challenged with Norwalk, Snow Mountain, or Hawaii virus were evaluated by solid-phase enzyme immunoassay using recombinant Norwalk virus capsid antigen (rNV). Fourfold or greater serum immunoglobulin G (IgG) antibody responses to rNV wer... |
7686045 | Effect of polyanions on the unfolding of acidic fibroblast growth factor. | The urea-induced unfolding of acidic fibroblast growth factor (aFGF) in the presence and absence of various polyanions has been quantitatively examined by fluorescence spectroscopy. In the absence of a stabilizing polyanion, the apparent free energy of unfolding of aFGF is 6.5 kcal mol-1. The presence of equimolar or g... |
8516329 | Molecular characterization of the 128-kDa immunodominant antigen of Helicobacter pylori associated with cytotoxicity and duodenal ulcer. | Helicobacter pylori has been associated with gastritis, peptic ulcer, and gastric adenocarcinoma. We report the nucleotide sequence and expression of an immunodominant antigen of H. pylori and the immune response to the antigen during disease. The antigen, named CagA (cytotoxin-associated gene A), is a hydrophilic, sur... |
8516310 | Yeast calmodulin and a conserved nuclear protein participate in the in vivo binding of a matrix association region. | Chromatin becomes reorganized during mitosis each cell cycle. To identify genes potentially involved in these supramolecular events, we have used a colony-color assay to screen temperature-sensitive mutants of Saccharomyces cerevisiae. When a sequence that mediates attachment to the nuclear matrix in vitro was inserted... |
8516297 | Conservation of genetic information: a code for site-specific DNA recognition. | We present findings of genetic information conservation between the glucocorticoid response element (GRE) DNA and the cDNA encoding the glucocorticoid receptor (GR) DNA-binding domain (DBD). The regions of nucleotide sub-sequence similarity to the GRE in the GR DBD occur specifically at nucleotide sequences on the ends... |
8515427 | Multiple binding modes for the receptor-bound conformations of cyclic AII agonists. | Angiotensin II, Asp-Arg-Val-Tyr-His-Pro-Phe, binds its receptor with a postulated turn centered at residue four. Analogs of angiotensin II which contain a disulfide bridge between the side chains of residues 3 and 5 retain significant activity consistent with this hypothesis. Incorporation of 4-mercaptoproline residues... |
8514880 | Early molecular replication of human immunodeficiency virus type 1 in cultured-blood-derived T helper dendritic cells. | The rate and efficiency of key steps in the life cycle of the human immunodeficiency virus type 1 was examined in three primary cell types, T cells, monocytes, and T helper dendritic cells using the same quantity of virus involved and same cell number. The results show that viral DNA synthesis proceeds much more rapidl... |
8512927 | The primary self-assembly reaction of bacteriophage lambda cI repressor dimers is to octamer. | 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. It has long been believed that cooperativity is mediated by self-assembly of repressor dimers to form tetramers which can then bind simultaneously to adjac... |
8512803 | Biological activities of phthalocyanines--XVI. Tetrahydroxy- and tetraalkylhydroxy zinc phthalocyanines. Effect of alkyl chain length on in vitro and in vivo photodynamic activities. | Zinc phthalocyanine substituted with four hydroxyl groups attached to the macrocycle, either directly or via spacer chains of three or six carbon atoms, were tested for their photodynamic ability to inactivate Chinese hamster lung fibroblasts (line V-79) in vitro, and to induce regression of EMT-6 tumours grown subcuta... |
8509447 | Sorting of membrane components from endosomes and subsequent recycling to the cell surface occurs by a bulk flow process. | A central question in the endocytic process concerns the mechanism for sorting of recycling components (such as transferrin or low density lipoprotein receptors) from lysosomally directed components; membrane-associated molecules including receptors are generally directed towards the recycling pathway while the luminal... |
7685276 | The Escherichia coli FIS protein is not required for the activation of tyrT transcription on entry into exponential growth. | The Escherichia coli DNA bending protein factor for inversion stimulation (FIS), is neither necessary nor responsible for the stimulation of transcription from the wild type promoter for the tyrT operon (encoding a species of tyrosine tRNA) that occurs upon resumption of exponential growth. This conclusion is unexpecte... |
8506367 | Azamacrolides: a family of alkaloids from the pupal defensive secretion of a ladybird beetle (Epilachna varivestis). | Defensive droplets from glandular hairs of the pupa of the Mexican bean beetle, Epilachna varivestis, contain a group of structurally novel alkaloids, the azamacrolides. The major constituent of this secretion, epilachnene, is shown to be (5Z)-11-propyl-12-azacyclotetradec-5-en-14-olide. The secretion also contains an ... |
8389464 | Prevention of metastasis by inhibition of the urokinase receptor. | The plasminogen activator urokinase (u-PA) mediates proteolysis by a variety of human tumor cells. Competitive displacement of u-PA from cellular binding sites results in decreased proteolysis in vitro, suggesting that the cell surface is the preferred site for u-PA-mediated protein degradation. We studied the effect o... |
8503876 | Effects of tetrahydrofolate polyglutamates on the kinetic parameters of serine hydroxymethyltransferase and glycine decarboxylase from pea leaf mitochondria. | Plant tissues contain highly conjugated forms of folate. Despite this, the ability of plant folate-dependent enzymes to utilize tetrahydrofolate polyglutamates has not been examined in detail. In leaf mitochondria, the glycine-cleavage system and serine hydroxymethyltransferase, present in large amounts in the matrix s... |
8503172 | Assembly of the matrix protein of simian immunodeficiency virus into virus-like particles. | To obtain a better understanding of the processes of assembly and morphogenesis of simian immunodeficiency virus (SIV), recombinant vaccinia viruses containing regions of the gag-pol open reading frame were constructed and their intracellular expression as well as the ability of the Gag polypeptides to be released into... |
7684774 | Surface and cytoskeletal markers of rostrocaudal position in the mammalian nervous system. | To identify cell surface molecules that define position in the mammalian nervous system, we previously characterized the binding of two monoclonal antibodies, ROCA1 and ROCA2, to adult rat sympathetic ganglia and intercostal nerves. The binding of ROCA1 is highest in rostral ganglia and nerves and declines in a graded ... |
8501117 | Fluorescence anisotropy imaging microscopy maps calmodulin binding during cellular contraction and locomotion. | Calmodulin is a calcium transducer that activates key regulatory and structural proteins through calcium-induced binding to the target proteins. A fluorescent analog of calmodulin in conjunction with ratio imaging, relative to a volume indicator, has demonstrated that calmodulin is uniformly distributed in serum-depriv... |
8501039 | Nucleotide sequence of the celG gene of Clostridium thermocellum and characterization of its product, endoglucanase CelG. | The nucleotide sequence of the celG gene of Clostridium thermocellum, encoding endoglucanase CelG, was determined. The open reading frame extended over 1,698 bp and encoded a 566-amino-acid polypeptide (molecular weight of 63,128) similar to the C. thermocellum endoglucanase CelB (51.5% identical residues). The N termi... |
8501034 | Characterization of the cobalamin (vitamin B12) biosynthetic genes of Salmonella typhimurium. | Salmonella typhimurium synthesizes cobalamin (vitamin B12) de novo under anaerobic conditions. Of the 30 cobalamin synthetic genes, 25 are clustered in one operon, cob, and are arranged in three groups, each group encoding enzymes for a biochemically distinct portion of the biosynthetic pathway. We have determined the ... |
8501030 | Dual response regulators (NarL and NarP) interact with dual sensors (NarX and NarQ) to control nitrate- and nitrite-regulated gene expression in Escherichia coli K-12. | Two sensor proteins, NarX and NarQ, mediate nitrate regulation of anaerobic respiratory gene expression. Either of these sensors is sufficient to signal the presence of nitrate to the response regulator protein, NarL, a transcriptional activator and repressor. Two observations suggested the existence of a second respon... |
8500889 | Facilitation of complement-dependent killing of the Lyme disease spirochete, Borrelia burgdorferi, by specific immunoglobulin G Fab antibody fragments. | In the absence of specific antibody, Borrelia burgdorferi is resistant to the bactericidal action of complement, despite the capacity of the spirochete to activate complement. Complement-mediated killing of B. burgdorferi requires the presence of antiborrelial immunoglobulin G (IgG). The effect of bactericidal IgG take... |
8500874 | Characterization of pertussis toxin analogs containing mutations in B-oligomer subunits. | The S2, S3, and S4 subunit genes of pertussis toxin (PT) from Bordetella pertussis were subjected to site-directed mutagenesis, and the resultant PT analogs were assayed for altered biological properties. PT analogs S2(T91,R92,N93) delta and S2(Y102A,Y103A) exhibited reduced binding to fetuin. Several PT analogs with m... |
8499413 | Inhibition of smooth muscle cell proliferation and experimental angioplasty restenosis by beta-cyclodextrin tetradecasulfate. | Heparin inhibits smooth muscle cell proliferation in vitro, a property that makes it potentially useful in preventing restenosis after angioplasty. Its utility in this setting is limited by the inability to use high doses (secondary to anticoagulant effects) and the need for subcutaneous administration. We tested the a... |
8388547 | Analysis of a protein-binding domain of p53. | The tumor suppressor protein p53 was first isolated as a simian virus 40 large T antigen-associated protein and subsequently was found to function in cell proliferation control. Tumor-derived mutations in p53 occur predominantly in four evolutionarily conserved regions spanning approximately 50% of the polypeptide. Pre... |
8388546 | Double-stranded RNA activates novel factors that bind to the interferon-stimulated response element. | Infection of cells with adenovirus or transfection of cells with double-stranded RNA (dsRNA) activates transcription of the alpha/beta interferon-stimulated genes (ISGs). Induction of ISG expression by adenovirus appears to be mediated through the same DNA target that is responsive to alpha/beta interferons, the interf... |
8388537 | Meiosis-specific arrest revealed in DNA topoisomerase II mutants. | Although the processes of mitosis and meiosis are similar, there is evidence for fundamental regulatory differences between the two. To examine these differences, we have compared the meiotic phenotype of DNA topoisomerase II mutants with their previously described mitotic phenotype (C. Holm, T. Goto, J. Wang, and D. B... |
8497250 | The response of gamma interferon activation factor is under developmental control in cells of the macrophage lineage. | Gamma interferon activation factor (GAF) rapidly induces transcriptional activation of gamma interferon (IFN-gamma)-responsive genes. Conversion of the GAF from a latent cytoplasmic to an activated, DNA-binding form is an immediate step in the cellular response to IFN-gamma. The amount of IFN-gamma-activated GAF, measu... |
7684473 | Hybrid hepatitis B virus nucleocapsid bearing an immunodominant region from hepatitis B virus surface antigen. | A hepatitis B core antigen (HBcAg) gene bearing the 39-amino-acid-long domain A of hepatitis B surface antigen (HBsAg) within the HBcAg immunodominant loop has been constructed and expressed in Escherichia coli. Chimeric capsids demonstrated HBs but not HBc antigenicity and elicited in mice B-cell and T-cell responses ... |
8497072 | Association of human immunodeficiency virus type 1 envelope glycoprotein with particles depends on interactions between the third variable and conserved regions of gp120. | Many regions within the envelope of human immunodeficiency virus type 1 (HIV-1) that affect its structure and function have been identified. We have previously reported that the interaction of the second conserved (C2) and third variable (V3) regions of gp120 influences the ability of HIV-1 to establish a productive in... |
8497052 | Ribonucleoprotein complexes of hepatitis delta virus. | Human hepatitis delta virus (HDV) is a subviral satellite agent of hepatitis B virus (HBV). The envelope proteins of HDV are provided by the helper virus, HBV, but very little is known about the internal structure of HDV. The particles contain multiple copies of the delta antigen and an unusual RNA genome that is small... |
8497050 | Characterization of a temperature-sensitive influenza B virus mutant defective in neuraminidase. | ts5, a temperature-sensitive mutant of influenza B virus, belongs to one of seven recombination groups. When the mutant infected MDCK cells at the nonpermissive temperature (37.5 degrees C), infectious virus was produced at very low levels compared with the yield at the permissive temperature (32 degrees C) and hemaggl... |
8497047 | Hybrid human immunodeficiency virus Gag particles as an antigen carrier system: induction of cytotoxic T-cell and humoral responses by a Gag:V3 fusion. | In attempts to increase the immunogenicity of recombinant antigens, a number of particulate antigen presentation systems have been developed. In this study, we used human immunodeficiency virus Gag particles as carriers for the human immunodeficiency virus envelope V3 region. Gag:V3 fusion proteins were expressed from ... |
8496678 | Protein rib: a novel group B streptococcal cell surface protein that confers protective immunity and is expressed by most strains causing invasive infections. | The group B Streptococcus, an important cause of invasive infections in the neonate, is classified into four major serotypes (Ia, Ib, II, and III) based on the structure of the polysaccharide capsule. Since the capsule is a known virulence factor, it has been extensively studied, in particular in type III strains, whic... |
19431898 | Harmonic system analysis of the algae Valonia utricularis: contribution of an electrogenic transport system to gain and phase-shift of the transfer function. | Cell membrane properties of the giant marine alga Valonia utricularis were measured in the frequency domain between 1 Hz and 10 MHz by harmonic system analysis. Harmonic analysis was performed by imposing a sinusoidal electrical voltage on the cell interior via an internal microelectrode. Gain and phase-shift of the re... |
18965725 | Fluorescence properties of 1-naphthol, 2-naphthol and 1,2,3,4-tetrahydronaphthol in aqueous alcohol solvents with and without beta-cyclodextrin. | The fluorescence properties of 1-naphthol, 2-naphthol and 1,2,3,4-tetrahydronaphthol were obtained in binary aqueous-alcohol solvents with and without beta-cyclodextrin. The fluorescence of both the molecular and anionic forms of 1-naphthol and 2-naphthol were observed in the binary solvents without beta-cyclodextrin. ... |
18965710 | Synergistic extraction of cobalt(II) from cesium containing aqueous solutions with mixtures of 4-acyl-pyrazol-5-ols and crown ethers. | The synergistic extraction of cobalt(II) from aqueous solutions loaded with cesium chloride or nitrate, with mixtures of 1-phenyl-3-methyl-4-acyl-pyrazol-5-ols (HL) [acyl = benzoyl (HPMBP), para-tert.-butyl-benzoyl (HPMB'P), stearoyl (HPMSP)] and crown ethers E = B15C5, 18C6, DC18C6, DB18C6 and DB24C8 (DC = dicyclohexa... |
8143093 | Scanning electron microscopy of synaptonemal complexes. | The novel application of scanning electron microscopy to study whole-mount surface-spread synaptonemal complex complements of rye (Secale cereale) and rat (Rattus norvegicus) is described. Scanning electron microscopy is able to resolve the third dimension in such preparations and improve the tracing of the continuity ... |
8143092 | Organization and molecular cytogenetics of a satellite DNA family from Hoplias malabaricus (Pisces, Erythrinidae). | The chromosomes of the primitive South American teleost fish Hoplias malabaricus have been analyzed by classical cytogenetic (C-, AgNOR-, Hoechst 33258-, and Q-banding) techniques. A highly repetitive DNA family has been cloned and sequenced. It is a tandemly repeated sequence of about 355 bp, yielding an overall base ... |
8143091 | Inverted and satellited Y chromosome in the orangutan (Pongo pygmaeus). | An inverted and satellited Y chromosome of almost acrocentric appearance was detected in seven of 14 male orangutans. In the remaining seven animals a submetacentric Y chromosome without NORs occurred. The high frequency with which the satellited Y chromosomes were associated with acrocentric autosomes and the positive... |
8143090 | Multi-chromosomal location of ribosomal RNA genes and heterochromatin association in brown trout. | The ribosomal rRNA genes have been mapped by fluorescent in situ hybridization (FISH) to brown trout chromosomes. One major NOR chromosome pair and 8 novel minor NOR chromosome pairs have been found. Both major and minor NORs were closely related to polymorphic heterochromatin, as revealed by FISH and C-banding. These ... |
8143089 | Aneuploidy, structural chromosome changes, and DNA amounts in the annual taxa of the Haplopappus spinulosus complex. | Haplopappus gracilis (n = 2), Haplopappus ravenii (n = 4), and Haplopappus wigginsii (n = 4) are isolated by F1 hybrid sterility due mainly to translocation heterozygosity. There is no evidence that this can be overcome at the diploid level so that introgression can occur among them. They are also separated geographica... |
8143087 | Direct detection of repetitive, whole chromosome paint and telomere DNA probes by immunogold electron microscopy. | Biotinylated repetitive, whole chromosome paint and telomere DNA probes were investigated at the electron microscope level after non-isotopic in situ hybridization and direct immunogold detection. The protocol described allowed the visualization of a biotinylated chromosome 1 specific satellite DNA probe in the light m... |
8143086 | Meiotic synapsis of homogeneously staining regions (HSRs) in chromosome 1 of Mus musculus. | About 50 copies of a long-range repeat DNA family with a repeat size of roughly 100 kb and with sequence homology to mRNAs are clustered in the G-light band D of chromosome 1 of the house mouse, Mus musculus. We studied amplified versions of the cluster which are found in many wild populations of M. musculus. They are ... |
8143085 | A protein homologous to human Ku p70-protein is required for reconstitution of Xenopus sperm pronuclei. | The monoclonal antibody mAbH6, which recognizes one human Ku-protein (p70), cross-reacted with the counterpart protein from Xenopus eggs. The Xenopus antigen purified with a mAbH6-Sepharose column was a complex of 88 kDa and 72 kDa proteins. The role of Ku protein in nuclear structure formation was studied using a cell... |
8143084 | Segregation of holocentric chromosomes at meiosis in the nematode, Caenorhabditis elegans. | The meiotic segregation of the holocentric chromosomes of Caenorhabditis elegans in both spermatogenesis and oogenesis is described. The extended kinetochore typical of the mitotic chromosome could not be differentiated on meiotic bivalents; instead microtubules appeared to project into the chromatin. The meiotic spind... |
8219987 | [The relationship between the magnitude of the negative inotropic action and chemical structure of crown-ether derivatives]. | The relationship between the inotropic effect and chemical structure of 15-crown-5 and 18-crown-6 derivatives was studied in experiments in open-chest anaesthesized cats, by using computer-aided analysis. The findings showed that the 15-crown-5 derivatives produced more pronounced cardiotropic effect and they were less... |
8219986 | [The effect of a crown-ether derivative, ethmozine and etatsizin on the functioning of the calcium pools in the guinea pig myocardium]. | Analysis of the component structure of single contractions of papillary muscles in guinea pigs was used to study the effects of the crown ether derivative benzylase-15-crown-5 and the antiarrhythmic agents ethmozine and ethacizine. The negative inotropic effect of these compounds was shown to be associated with limited... |
8413835 | Steroid hormones and receptors of the GABAA supramolecular complex. II. Progesterone and estrogen inhibitory effects on the chloride ion channel receptor in different forebrain areas of the female rat. | The inhibitory effect of female sex steroid hormones on the binding of [35S]t-butylbicyclophosphorothionate [35S]TBPS to the chloride ion channel receptor in different forebrain areas of the female rat proved to be of a differential nature. The in vivo administration of estradiol and estradiol+progesterone were respons... |
8413834 | Steroid hormones and receptors of the GABAA supramolecular complex. I. Benzodiazepine receptor level changes in some extrahypothalamic brain areas of the female rat following sex steroid treatment. | The effects of sex steroid hormones on the different receptor binding sites of the GABAA molecule remain unclear. In this report we have demonstrated, using autoradiography techniques, that the distribution pattern of the benzodiazepine receptors (a component of the GABAA molecule) in some extrahypothalamic brain regio... |
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