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7520695 | Interaction between glycine decarboxylase, serine hydroxymethyltransferase and tetrahydrofolate polyglutamates in pea leaf mitochondria. | The aim of the present work was to further determine how the T-protein of the glycine-cleavage system and serine hydroxy-methyltransferase (SHMT), two folate-dependent enzymes from pea leaf mitochondria, interact through a common pool of tetrahydrofolate polyglutamates (H4PteGlun). It was observed that the binding affi... |
8065376 | Characterization of biosynthetic IgG oligomers resulting from light chain variable domain duplication. | We have characterized a human IgG1 monoclonal antibody composed of altered light chains. Each light chain consists of two identical variable domains and a kappa constant domain, in association with a normal gamma chain. This antibody assembled biosynthetically into a mixture of stable oligomers and monomers. Employing ... |
8062821 | Electrostatic attraction by surface charge does not contribute to the catalytic efficiency of acetylcholinesterase. | Acetylcholinesterases (AChEs) are characterized by a high net negative charge and by an uneven surface charge distribution, giving rise to a negative electrostatic potential extending over most of the molecular surface. To evaluate the contribution of these electrostatic properties to the catalytic efficiency, 20 singl... |
8061001 | Four aromatic residues in the active center of cyclodextrin glucanotransferase from alkalophilic Bacillus sp. 1011: effects of replacements on substrate binding and cyclization characteristics. | Three-dimensional structures of cyclodextrin glucanotransferases (CGTases) have revealed that four aromatic residues, which are highly conserved among CGTases but not found in alpha-amylases, are located in the active center. To analyze the roles of these aromatic residues, Phe-183, Tyr-195, Phe-259, and Phe-283 of Bac... |
8058729 | Independent in vitro assembly of a ribonucleoprotein particle containing the 3' domain of 16S rRNA. | Small (30S) subunits of Escherichia coli ribosomes are composed of 21 proteins and a 1542-nucleotide 16S rRNA, whose secondary structure is divided into three domains. An in vitro transcript of the 3' domain of 16S rRNA (residues 923-1542), assembles efficiently with 30S ribosomal proteins to form a compact ribonucleop... |
8053908 | Strategic manipulation of the substrate specificity of Saccharomyces cerevisiae flavocytochrome b2. | Flavocytochrome b2 from Saccharomyces cerevisiae acts physiologically as an L-lactate dehydrogenase. Although L-lactate is its primary substrate, the enzyme is also able to utilize a variety of other (S)-2-hydroxy acids. Structural studies and sequence comparisons with several related flavoenzymes have identified the k... |
8053688 | Direct affinity purification and supramolecular organization of human lysosomal cathepsin A. | Cathepsin A (also named "protective protein" and carboxypeptidase L) stabilizes beta-galactosidase and activates neuraminidase by forming with them a high-molecular-weight lysosomal complex. We determined the main forms of the supramolecular organization of human placental cathepsin A and the quantitative relationship ... |
8051707 | To build a virus capsid. An equilibrium model of the self assembly of polyhedral protein complexes. | The capsids of spherical (icosahedral) viruses are constructed of multiples of 60 subunits. The question of how these polymers assemble is basic to understanding the viral life cycle. A formalism describing virus assembly as an equilibrium between coat protein subunits, assembly intermediates and intact virus is presen... |
8051180 | Phosphorylation and supramolecular organization of murine small heat shock protein HSP25 abolish its actin polymerization-inhibiting activity. | Characteristic features of mammalian small heat shock proteins are their rapid phosphorylation in response to stress and mitogenic signals and their ability to form multimeric particles of 200-700 kDa and large aggregates up to 5000 kDa. Recently, a chaperoning function and an actin polymerization-inhibiting activity w... |
8051028 | Cloning, expression, and nucleotide sequence of the alpha-amylase gene from the haloalkaliphilic archaeon Natronococcus sp. strain Ah-36. | The alpha-amylase gene of a Natronococcus sp. (1,512 bp) contained a signal peptide of 43 amino acids. Haloferax volcanii expressed the gene and cleaved the signal peptide accurately. The signal peptide shared an extremely high amino acid sequence identity with that of a protease from the halophilic archaeon 172P1. |
8051015 | Phylogenetic analysis of sequences from diverse bacteria with homology to the Escherichia coli rho gene. | Genes from Pseudomonas fluorescens, Chromatium vinosum, Micrococcus luteus, Deinococcus radiodurans, and Thermotoga maritima with homology to the Escherichia coli rho gene were cloned and sequenced, and their sequences were compared with other available sequences. The species for all of the compared sequences are membe... |
7519595 | micF antisense RNA has a major role in osmoregulation of OmpF in Escherichia coli. | micF RNA, produced from a multicopy plasmid, was originally shown to be a major factor in negative osmoregulation of the OmpF outer membrane protein in Escherichia coli. However, subsequent experiments with a micF deletion strain suggested that chromosomal micF RNA was not a key component in this process. We report her... |
8050991 | Eubacteria show their true colors: genetics of carotenoid pigment biosynthesis from microbes to plants. | The opportunities to understand eubacterial carotenoid biosynthesis and apply the lessons learned in this field to eukaryotes have improved dramatically in the last several years. On the other hand, many questions remain. Although the pigments illustrated in Fig. 2 represent only a small fraction of the carotenoids fou... |
8045926 | Interactions and three-dimensional localization of a group of nuclear pore complex proteins. | We have used antibodies directed against a number of nuclear pore complex (NPC) proteins to determine their mutual interactions and location within the three-dimensional structure of the NPC. A monoclonal antibody, termed QE5, recognized three NPC polypeptides, p250, NUP153, and p62 on Western blots, and labeled the nu... |
8040318 | Differential effects of metalloporphyrins on messenger RNA levels of delta-aminolevulinate synthase and heme oxygenase. Studies in cultured chick embryo liver cells. | The acute porphyrias in relapse are commonly treated with intravenous heme infusion to decrease the activity of delta-aminolevulinic acid synthase, normally the rate-controlling enzyme in heme biosynthesis. The biochemical effects of heme treatment are short-lived, probably due in part to heme-mediated induction of hem... |
8040316 | Mutations of CpG dinucleotides located in the triiodothyronine (T3)-binding domain of the thyroid hormone receptor (TR) beta gene that appears to be devoid of natural mutations may not be detected because they are unlikely to produce the clinical phenotype of resistance to thyroid hormone. | Thyroid hormone receptor (TR) beta gene mutations identified in patients with resistance to thyroid hormone (RTH) revealed two clusters ("hot" areas) of mutations (RTHmut) in the triiodothyronine (T3)-binding domain. Furthermore, 45% of RTHmuts and 90% of recurring mutations are located in CpG dinucleotides ("hot spots... |
8039912 | Platelet microbicidal protein alone and in combination with antibiotics reduces Staphylococcus aureus adherence to platelets in vitro. | Bacterial adherence to platelets on the cardiac valve surface is believed to be critical in the induction of infective endocarditis. Recent studies have confirmed that thrombin-activated platelets secrete platelet microbicidal protein (PMP), which can both kill and exert nonlethal antiadherence effects against endovasc... |
7913698 | Construction of an MR/P fimbrial mutant of Proteus mirabilis: role in virulence in a mouse model of ascending urinary tract infection. | Proteus mirabilis, a cause of acute pyelonephritis, produces at least four types of fimbriae, including MR/P (mannose-resistant/Proteus-like) fimbriae. To investigate the contribution of MR/P fimbriae to colonization of the urinary tract, we constructed an MR/P fimbrial mutant by allelic exchange. A 4.2-kb BamHI fragme... |
7518566 | GATA-binding proteins regulate the human gonadotropin alpha-subunit gene in the placenta and pituitary gland. | The human glycoprotein hormone alpha-subunit gene is expressed in two quite dissimilar tissues, the placenta and anterior pituitary. Tissue-specific expression is determined by combinations of elements, some of which are common and others of which are specific to each tissue. In the placenta, a composite enhancer confe... |
8035786 | Involvement of the transcription factor PU.1/Spi-1 in myeloid cell-restricted expression of an interferon-inducible gene encoding the human high-affinity Fc gamma receptor. | Induction by gamma interferon (IFN-gamma) of the gene encoding the human high-affinity Fc gamma receptor (Fc gamma R1) in myeloid cells requires an IFN-gamma response region (GRR) and a myeloid cell-activating transcription element (MATE). GRR and MATE interact with factors to form, respectively, an IFN-gamma-activatin... |
8035523 | Macrophage-tropic and T-cell line-adapted chimeric strains of human immunodeficiency virus type 1 differ in their susceptibilities to neutralization by soluble CD4 at different temperatures. | Molecular clones of three macrophage-tropic and three T-cell line-adapted strains of human immunodeficiency virus type 1 (HIV-1) were used to explore the mechanism of HIV-1 resistance to neutralization by soluble CD4 (sCD4). The three macrophage-tropic viruses, each possessing the V3 and flanking regions of JR-FL, were... |
7518531 | European brown hare syndrome virus: relationship to rabbit hemorrhagic disease virus and other caliciviruses. | Monoclonal antibodies directed against the capsid protein of rabbit hemorrhagic disease virus (RHDV) were used to identify field cases of European brown hare syndrome (EBHS) and to distinguish between RHDV and the virus responsible for EBHS. Western blot (immunoblot) analysis of liver extract of an EBHS virus (EBHSV)-i... |
8035511 | Three-dimensional structure of baculovirus-expressed Norwalk virus capsids. | The three-dimensional structure of the baculovirus-expressed Norwalk virus capsid has been determined to a resolution of 2.2 nm using electron cryomicroscopy and computer image processing techniques. The empty capsid, 38.0 nm in diameter, exhibits T = 3 icosahedral symmetry and is composed of 90 dimers of the capsid pr... |
8035496 | Differential regulation of cellular tropism and sensitivity to soluble CD4 neutralization by the envelope gp120 of human immunodeficiency virus type 1. | Using recombinant and mutant viruses generated between two human immunodeficiency virus type 1 isolates that display differences in cell tropism and sensitivity to soluble CD4 neutralization, we show that these two properties of the virus are regulated by different mechanisms. Whereas there is an association between V3... |
24222002 | Ion spray-tandem mass spectrometry of supramolecular coordination complexes. | Double-helical [M2L2] (n+), triple-helical [M2L3] (n+), and toroidal [M3L3] (n+) (M = Cu, Co, Fe, Ni, La, Eu, Gd, Tb, or Lu) supramolecular complexes have been fully characterized by ion spray mass spectrometry (IS-MS). The IS-MS spectra from pure acetonitrile solutions reflect the nature of the cations present in solu... |
24222000 | Analysis of hydrocarbon dendrimers by laser desorption time-of-flight and fourier transform mass spectrometry. | The first mass spectrometric analysis of a new class of hydrocarbon dendrimers that result from a convergent synthetic approach is reported. Molecular weights of a series of phenylacetylene dendrimers (715 to 14776 u MW) are characterized by ultraviolet matrix-assisted laser desorption (MALDltime-of-flight (TOF) mass s... |
17736274 | Excimers and exciplexes of conjugated polymers. | Observations of intermolecular excimers in several pi-conjugated polymers and exciplexes of these polymers with tris(p-tolyl) amine are reported. It is shown that the luminescence of conjugated polymer thin films originates from excimer emission and that the generally low quantum yield is the result of self-quenching. ... |
7800189 | [Multiple organ failure (MOF) in tertian malaria. Report of a clinical case]. | The authors describe a malignant malaria clinic case complicated by shock, disseminated intravascular coagulation (DIC) and multiple organ failure (renal, heart, lung failure): MOF. Early diagnosis and suitable therapy, with multiple organ failure intensive care allowed a good patient outcome. |
7993380 | [Synthesis and cloning of genes for the antisense peptides for human calcitonin and miniproinsulin]. | Because of the potential significance of the 'molecular recognition' theory for studies in molecular biology and biotechnology, the theory is worth being examined using methods of chemical-enzymatic gene synthesis, recombinant DNA construction and microbiological peptide synthesis. We therefore undertook the synthesis ... |
7989646 | Interaction of some anti-hypoxia drugs with hydroxypropyl-beta-cyclodextrin studied by means of charge transfer chromatography. | The interaction of 12 anti-hypoxia drugs with hydroxypropyl-beta-cyclodextrin (HPBCD) and the influence of LiCl, NaCl and KCl on the strength of interaction was studied by charge transfer chromatography. Most of the drugs form inclusion complexes with HPBCD and the relative strength of interaction varies markedly accor... |
7987195 | [The properties of glycogenolytic enzymes and their activation characteristics in the muscle tissue of vertebrates with different ecologies]. | The supramolecular structure of glycogenolytic enzymes on intracellular organelles, their properties, and specific features of their regulation largely depend on ecological factors. Development of an ordered supramolecular structure on a glycogen granule and strength of the bond between its components are determined by... |
7981660 | A study on the mechanism of polymerisation of Bacillus brevis flagellin. | Optical properties of intact flagellin and of modified-on-tyrosine flagellin incapable of self-assembly have been studied by the circular dichroism (CD) method. The CD spectra of both flagellins do not change and virtually coincide within the pH range from 2.9 to 10.0. In the presence of polyethylene glycol (PEG) and a... |
7969915 | The beaded form of myelinated nerve fibers. | When the nerves are lightly stretched and fixed by freeze-substitution, their fibers show the form-change termed "beading" which consists of a series of undulating constrictions and swellings in the internodes. This form change has not ordinarily been seen in chemically fixed nerves, or when it has, it has been ascribe... |
7952101 | Capillary electrophoretic separation of nucleotide isomers via complexation with cyclodextrin and borate. | The electrophoretic behaviour of monophosphorylated nucleotide isomers can be manipulated using complex-forming reactions with beta-cyclodextrin (beta-CD) and borate. Resolution of the 2'- and 3'-isomers of nucleotides is possible when the electrophoresis buffer contains 10 mM CD. The effect of beta-CD concentration on... |
7952093 | Cyclodextrins as enantioselective mobile phase modifiers for chiral capillary electrophoresis. Effects of pH and cyclodextrin concentration. | When cyclodextrins (CDs) are used as enantioselective mobile phase modifiers for capillary electrophoresis, optimization of chiral resolution is usually carried out by varying operational parameters such as the choice of CD type, CD concentration and pH of the operating buffer. This work describes the effects of the ab... |
7942149 | Inhibitory effects of bisphosphonates on growth of amoebae of the cellular slime mold Dictyostelium discoideum. | Bisphosphonates are inhibitors of bone resorption and are used increasingly as therapeutic agents for treating clinical disorders of skeletal metabolism. Their mode of action is still not fully understood. The demonstration that methylenebisphosphonate, a simple methylene analog of pyrophosphate, inhibits the axenic gr... |
7921649 | Mapping and organization of highly-repeated DNA sequences by means of simultaneous and sequential FISH and C-banding in 6x-triticale. | Three families of highly repeated sequences from rye and the rRNA multigenes (NOR and 5S) have been mapped by FISH and C-banding, in chromosomes of triticale. The pSc119.2 probe showed interstitial hybridization in chromosome arms 1RS, 1RL, 4RL, 5RL, 6RS, 6RL, 7RS and 7RL, and is very effective for chromosome identific... |
7921648 | Further data on the occurrence and evolution of satellite DNA families in the lacertid genome. | This paper reports the isolation and characterization of two HindIII repetitive DNA families from the genome of two lacertid lizards, Podarcis sicula and Lacerta saxicola. These satellites did not appear to be related to each other. The consensus sequences of their monomeric units did not show any similarity, though bo... |
7921647 | Synapsis and chiasma formation in four meiotic mutants of tomato (Lycopersicon esculentum). | Synapsis and chiasma formation were studied in pollen mother cells of four meiotic mutants of tomato. The four mutants displayed defects in the assembly of the synaptonemal complex (SC) covering the whole range from almost complete absence of synapsis to complete synapsis at pachytene. In three mutants, we found a good... |
7921646 | Physical map of a 2 Mb chromosome of the intestinal protozoan parasite Giardia duodenalis. | The protozoan parasite, Giardia duodenalis, is regarded as the most primitive eukaryote. The two apparently identical nuclei presumably carry the same chromosomes but the number of different chromosomes in the organism is unknown. A genome map of G. duodenalis is required to resolve this issue and mapping studies were ... |
7921645 | A tandemly repetitive, centromeric DNA sequence from the Canadian woodland caribou (Rangifer tarandus caribou): its conservation and evolution in several deer species. | A highly repetitive DNA clone, designated Rt-Pst3, was isolated from the PstI digest of Canadian woodland caribou (Rangifer tarandus caribou; 2n = 70) genomic DNA. It was found to be a 991 bp monomer of a tandemly repeated DNA sequence comprising about 5.7% of the genome and localized to the centromeric regions of all ... |
7921644 | Chromosomal variation in the northwestern American newts of the genus Taricha (Caudata: Salamandridae). | Chromosomal variation was analysed in 22 populations of newts of the salmandrid genus Taricha of western North America, and compared with that of the eastern North American newts of the genus Notophthalmus. The karyotypes of the species Taricha and Notophthalmus were very similar. However, there was considerable variat... |
7921643 | The homoeologous relationships of the arms of wheat chromosomes 2A and 2D to chromosome 2B and their effect on homoeologous pairing. | Homoeologous relationships between the arms of wheat group 2 chromosomes were analysed by studying homoeologous pairing in wheat-rye hybrids. Chromosomes 2A and 2D were identified using telocentrics 2AS, 2DS or 2DL. The remaining wheat chromosomes and their arms were identified by C-banding. Wheat chromosomes in the hy... |
7921642 | Organization and chromosomal location of repetitive DNA sequences in three species of squamate reptiles. | Repetitive DNA sequences were isolated from the genomes of species representing three major clades of squamate reptiles. A repetitive sequence (Cn4C7) was isolated from the New Mexican whiptail lizard, Cnemidophorus neomexicanus. This sequence is distributed throughout the chromosomes, but is more concentrated in the t... |
7920210 | Uptake and metabolism of carcinogenic levels of tobacco-specific nitrosamines by Sudanese snuff dippers. | It was recently reported that toombak, a type of snuff used in the Sudan, contained unusually high levels of tobacco-specific nitrosamines. To estimate the internal dose of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) received by individuals who use this type of tobacco, urine from a group of users was analyzed... |
7919017 | Resonance Raman microspectroscopic characterization of eosinophil peroxidase in human eosinophilic granulocytes. | A resonance Raman microspectroscopic study is presented of eosinophil peroxidase (EPO) in human eosinophilic granulocytes. Experiments were carried out at the single cell level with laser excitation in Soret-, Qv-, and charge transfer absorption bands of the active site heme of the enzyme. The Raman signal obtained fro... |
7919004 | Vectorially oriented membrane protein monolayers: profile structures via x-ray interferometry/holography. | X-ray interferometry/holography was applied to meridional x-ray diffraction data to determine uniquely the profile structures of a single monolayer of an integral membrane protein and a peripheral membrane protein, each tethered to the surface of a solid inorganic substrate. Bifunctional, organic self-assembled monolay... |
8084241 | Rapid tissue oxygen tension mapping using 19F inversion-recovery echo-planar imaging of perfluoro-15-crown-5-ether. | Fluorine-19 inversion-recovery, echo-planar imaging (IR-EPI) was used in conjunction with a new PFC emulsion, perfluoro-15-crown-5-ether, to map the spatial distribution of oxygen tension in murine liver, spleen and radiation induced fibrosarcoma (RIF-1) tumors. Intravenously administered PFC emulsions were allowed to ... |
8080112 | Enhanced extraction of phenobarbital from serum with a designed artificial receptor. | The primary goal of this work was to determine whether artificial receptors that function on the basis of molecular recognition have analytical capabilities. As an example of such a receptor, we have chosen one directed toward barbiturates. Chloroform enriched with this artificial receptor (1 mM) can extract more than ... |
8075768 | Chemical profiling of pharmaceuticals by capillary electrophoresis in the determination of drug origin. | Capillary electrophoresis has been utilized to detect trace components in bulk pharmaceutical products, with emphasis on the identification of differences among manufacturers that can be used for source verification in suspect/counterfeit cases. Micellar electrokinetic capillary chromatography with sodium dodecyl sulfa... |
8074530 | Nucleotide sequence and expression of a novel pectate lyase gene (pel-3) and a closely linked endopolygalacturonase gene (peh-1) of Erwinia carotovora subsp. carotovora 71. | Our previous genetic analysis (J. W. Willis, J. K. Engwall, and A. K. Chatterjee, Phytopathology 77:1199-1205, 1987) had revealed a tight linkage between pel-3 (pel, pectate lyase gene) and peh-1 (peh, polygalacturonase gene) within the chromosome of Erwinia carotovora subsp. carotovora 71. Nucleotide sequencing, trans... |
8069872 | Crystal structure of a complex of alpha-cyclodextrin with 2-fluoro-4-nitrophenol.3H2O. | The crystal structure of a complex of alpha-cyclodextrin (alpha-CD) with 2-fluoro-4-nitrophenol.3H2O has been determined by the X-ray diffraction technique. The complex crystallizes in space group P2(1)2(1)2(1) with cell dimensions: a = 13.431(3), b = 15.299(4), c = 24.780(5) A. The structure was solved by direct metho... |
8055917 | Proteolytic removal of the C-terminal transmembrane region of cytochrome f during extraction from turnip and charlock leaves generates a water-soluble monomeric form of the protein. | Water-soluble, monomeric cytochrome f purified from leaves of turnip (Brassica rapa) and charlock (Sinapis arvensis) is approximately 3 kDa smaller than the protein in chloroplast thylakoid membranes determined by SDS/PAGE. Sequencing the N-terminal and C-terminal regions of the monomeric protein, by automated Edman de... |
7765085 | Bacterial toxicity of cyclodextrins: luminuous Escherichia coli as a model. | The effect of various concentrations of natural and chemically modified cyclodextrins on the luminescence of an Escherichia coli suspension was investigated. All cyclodextrins were found to reduce, albeit to a varying degree, the luminescence level of the bacterial cells, thus suggesting a direct interaction between th... |
8052534 | Synthetic polyamines stimulate in vitro transcription by T7 RNA polymerase. | The influence of nine synthetic polyamines on in vitro transcription with T7 RNA polymerase has been studied. The compounds used were linear or macrocyclic tetra- and hexaamine, varying in their size, shape and number of protonated groups. Their effect was tested on different types of templates, all presenting the T7 R... |
8052530 | A plant scaffold attached region detected close to a T-DNA integration site is active in mammalian cells. | Integration of foreign genes into plant genomes by the Agrobacterium T-DNA transfer system has been considered to occur at random. It has been speculated that the chromosomal structure of the integration site might affect the expression pattern of the introduced genes. To gain insight into the molecular structure of T-... |
8041757 | Modification of a hydrogen bond to a bacteriochlorophyll a molecule in the light-harvesting 1 antenna of Rhodobacter sphaeroides. | Site-directed mutagenesis has been used to examine the function of a highly conserved aromatic residue, alpha Trp43, in the light-harvesting 1 antenna of the photosynthetic bacterium Rhodobacter sphaeroides. In this antenna alpha Trp43 is thought to be located near the putative binding site for bacteriochlorophyll; in ... |
8041151 | Dietary fish oil enhances macrophage production of nitric oxide. | Nitric oxide (NO) is recognized as an important mediator of hemodynamic regulation and multisystem organ failure (MOF). Although polyunsaturated fatty acids (PUFA) are known to modify the elaboration of some humoral mediators in MOF, their effect upon NO production has not been evaluated. This study was designed to exa... |
7913682 | Conformational specificity of the chaperonin GroEL for the compact folding intermediates of alpha-lactalbumin. | The chaperonin GroEL binds unfolded polypeptides, preventing aggregation, and then mediates their folding in an ATP-dependent process. To understand the structural features in non-native polypeptides recognized by GroEL, we have used alpha-lactalbumin (alpha LA) as a model substrate. alpha LA (14.2 kDa) is stabilized b... |
7518692 | Evidence of xenon transport through the gramicidin channel: a 129Xe-NMR study. | Evidence is presented for Xe transport through the gramicidin A channel. This evidence for Xe transport through gramicidin A channels has been obtained using 129Xe-NMR spectroscopy. Three experiments were utilized. The first experiment involved monitoring the change in the chemical shift of 129Xe in the presence of inc... |
7518674 | Sugar-DNA molecular recognition: specific interaction of alpha-1,4-glucopyranose chains with DNA in the minor groove. | alpha(1,4) glucopyranose chains (dextrins) are shown to interact with DNA via hydrophobic interactions from the minor groove side, while alpha(1,6) dextrans do not bind DNA. The observed specific alpha(1,4) linked sugar-DNA interactions may have importance in recognition of DNA by ene-diyne class of antibiotics via the... |
8037698 | Purification and characterization of morphinone reductase from Pseudomonas putida M10. | The NADH-dependent morphinone reductase from Pseudomonas putida M10 catalyses the reduction of morphinone and codeinone to hydromorphone and hydrocodone respectively. Morphinone reductase was purified from crude cell extracts to apparent homogeneity in a single affinity-chromatography step using Mimetic Yellow 2. The p... |
8037693 | Okadaic acid treatment leads to a fragmentation of the trans-Golgi network and an increase in expression of TGN38 at the cell surface. | Okadaic acid (OA) is a protein phosphatase inhibitor which has, among other properties, previously been shown to induce a fragmentation of the cisternae of the Golgi stack [for review, see Lucocq (1992) J. Cell Sci. 103, 875-880]. The effects of OA an reversible and mimic intracellular events which occur during mitosis... |
8037690 | Analysis of peptidoglycan precursors in vancomycin-resistant Enterococcus gallinarum BM4174. | Vancomycin resistance in enterococci is an increasing clinical problem, and several phenotypes have been identified. We demonstrate here that the resistance mechanism in the constitutively vancomycin-resistant Enterococcus gallinarum BM4174 involves an altered pathway of peptidoglycan synthesis and hydrolysis of the no... |
8034728 | Regulated expression in vitro of genes coding for formate hydrogenlyase components of Escherichia coli. | Purified FHLA, the transcriptional activator of the formate regulon from Escherichia coli, is able to efficiently stimulate transcription from the sigma 54-dependent promoters of the fdhF, hyp, and hyc transcriptional units. Expression was dependent on the presence of sigma 54, of the upstream activatory sequence (UAS)... |
8033884 | Probing hydrogen-bonding interactions of bovine heart galectin-1 and methyl beta-lactoside by use of engineered ligands. | The binding of different synthetic monodeoxy, O-methyl and fluorodeoxy derivatives of methyl beta-lactoside to galectin-1 from bovine heart has been studied to probe the role of hydrogen bonding in the recognition and binding. The energetic contributions of the hydroxyl groups of methyl beta-lactoside directly involved... |
8031795 | Helix-forming tendencies of amino acids in short (hydroxybutyl)-L-glutamine peptides: an evaluation of the contradictory results from host-guest studies and short alanine-based peptides. | The helix propensities ("s-values") of amino acids measured using short alanine-based peptides are different, in both magnitude and rank order, from those found using random sequence copolymers of a "guest" amino acid and a (hydroxyalkyl)-L-glutamine "host". The origin of these differences is investigated here. In shor... |
8031791 | Molecular recognition in acetylcholinesterase catalysis: free-energy correlations for substrate turnover and inhibition by trifluoro ketone transition-state analogs. | Ten meta-substituted aryl trifluoromethyl ketones (m-XC6H4COCF3; X = H, CH3, CF3, C2H5, isopropyl, t-butyl, NH2, NMe2, N+Me3, NO2) have been evaluated as inhibitors of acetylcholinesterases from Electrophorus electricus and Torpedo californica. Trifluoro ketones that have small meta substituents (X = H, CH3, CF3, C2H5,... |
8031777 | X-ray crystallographic studies of a series of penicillin-derived asymmetric inhibitors of HIV-1 protease. | In the development of a treatment for AIDS, the HIV-1 protease has been identified as a good target enzyme for inhibitor design. We previously reported a series of dimeric penicillin-derived C2-symmetric HIV-1 protease inhibitors [Humber, D., et al. (1993) J. Med. Chem. 36, 3120-3128]. In an attempt to reduce the size ... |
8031776 | Single-site mutations in the C-terminal domain of bacteriophage lambda cI repressor alter cooperative interactions between dimers adjacently bound to OR. | Wild-type cI repressor dimers bind with 2.5-3 kcal/mol of cooperative free energy to the tripartite right operator region (OR) of bacteriophage lambda [Johnson, A. D., et al. (1981) Nature 294, 217-223; Brenowitz, M., et al. (1986) Methods Enzymol. 130, 132-181]. Quantitative modeling has suggested that cooperativity i... |
8031775 | Self-assembly of bacteriophage lambda cI repressor: effects of single-site mutations on the monomer-dimer equilibrium. | Dimerization of lambda cI repressor monomers is required for high-affinity binding to bacteriophage lambda operator DNA and is known to involve protein-protein contacts between C-terminal domains of the repressor monomers. In order to address the importance of the C-terminal domain in mediating the oligomeric propertie... |
8028050 | Lipopolysaccharide-induced CD11B-mediated neutrophil-endothelial adhesion is not required for polymorphonuclear cell priming. | Previous work has implicated both neutrophil-endothelial cell (PMN-EC) adhesion and PMN priming (enhanced superoxide production following activation) in the development of postinjury adult respiratory distress syndrome (ARDS) and multiple organ failure (MOF). CD11B, a member of the integrin family of PMN surface recept... |
7913140 | Elevated levels of soluble ICAM-1 correlate with the development of multiple organ failure in severely injured trauma patients. | Serum levels of interleukin-6, interleukin-8, the soluble receptor for tumor necrosis factor (sTNFr), and the soluble receptor for intercellular adhesion molecule-1 (sICAM-1) were measured serially in a series of 13 severely injured trauma patients to determine if any of these elements of the inflammatory response are ... |
7913124 | D1 agonist-induced excitation of substantia nigra pars reticulata neurons: mediation by D1 receptors on striatonigral terminals via a pertussis toxin-sensitive coupling pathway. | Iontophoresis of dopamine or the D1 agonist SKF 38393 has been shown to elicit current-dependent increases in the firing of rat substantia nigra pars reticulata neurons, suggesting a discrete physiological role for the D1 dopamine receptor population in the substantia nigra. The effects of SKF 38393 differed from those... |
8027175 | Crowding-induced organization of cytoskeletal elements: II. Dissolution of spontaneously formed filament bundles by capping proteins. | Through calculations of molecular packing constraints in crowded solutions, we have previously shown that dispersions of filament forming proteins and soluble proteins can be unstable at physiological concentrations, such that tight bundles of filaments are formed spontaneously, in the absence of any accessory binding ... |
8027060 | Identification of an adenosine receptor domain specifically involved in binding of 5'-substituted adenosine agonists. | The bovine A1 adenosine receptor (A1AR) and rat A3 adenosine receptor (A3AR) display distinct agonist and antagonist binding properties. To identify regions involved in ligand recognition, A1AR/A3AR chimeric receptors were created, expressed in COS-7 cells, and analyzed by radioligand binding. A chimeric receptor in wh... |
7517898 | Modulation of angiogenesis in vitro by laminin-entactin complex. | Laminin is a cross-shaped glycoprotein whose inner cross-region binds to the glycoprotein entactin (nidogen) forming a stable complex extractable from basement membrane matrices with chelating agents. In this study we evaluated the effect of the laminin-entactin complex on angiogenesis in serum-free collagen gel cultur... |
8022791 | Fatty acid synthesis: a potential selective target for antineoplastic therapy. | OA-519 is a prognostic molecule found in tumor cells from breast cancer patients with markedly worsened prognosis. We purified OA-519 from human breast carcinoma cells, obtained its peptide sequence, and unambiguously identified it as fatty acid synthase through sequence homology and enzymology. Tumor fatty acid syntha... |
8021220 | Purification and characterization of a 14-kilodalton protein that is bound to the surface of polyhydroxyalkanoic acid granules in Rhodococcus ruber. | The N-terminal amino acid sequence of the polyhydroxyalkanoic acid (PHA) granule-associated M(r)-15,500 protein of Rhodococcus ruber (the GA14 protein) was analyzed. The sequence revealed that the corresponding structural gene is represented by open reading frame 3, encoding a protein with a calculated M(r) of 14,175 w... |
8021210 | Phosphorylation of lipopolysaccharides in the Antarctic psychrotroph Pseudomonas syringae: a possible role in temperature adaptation. | Phosphorylation of lipopolysaccharide (LPS) from a psychrotrophic bacterium, Pseudomonas syringae, from Antarctica was studied by using sucrose gradient-separated membrane fractions. The bacterium was found to possess an LPS kinase which could phosphorylate more LPS postsynthetically at higher temperatures. The phospho... |
7912694 | Carboxy-terminal deletion analysis of the major pneumococcal autolysin. | Autolysins are endogenous enzymes that specifically degrade the covalent bonds of the cell walls and eventually can induce bacterial lysis. One of the best-characterized autolysins, the major pneumococcal LytA amidase, has evolved by the fusion of two domains, the N-terminal catalytic domain and the C-terminal domain r... |
8021182 | Biotransformation of benzothiophene by isopropylbenzene-degrading bacteria. | Isopropylbenzene-degrading bacteria, including Pseudomonas putida RE204, transform benzothiophene to a mixture of compounds. Induced strain RE204 and a number of its Tn5 mutant derivatives were used to accumulate these compounds and their precursors from benzothiophene. These metabolites were subsequently identified by... |
8021177 | Promoter and operator determinants for fur-mediated iron regulation in the bidirectional fepA-fes control region of the Escherichia coli enterobactin gene system. | The fepA-entD and fes-entF operons in the enterobactin synthesis and transport system are divergently transcribed from overlapping promoters, and both are inhibited by the Fur repressor protein under iron-replete conditions. A plasmid harboring divergent fepA'-phoA and fes-entF'-'lacZ fusions, both under the control of... |
8018538 | Comparative biodistributions of indium-111-labelled macrocycle chimeric B72.3 antibody conjugates in tumour-bearing mice. | A novel 111In ligand (a C-functionalised derivative of 1,4,7-triazacyclononanetriacetic acid), termed 9N3, was covalently attached to chimeric B72.3, labelled with 111In and compared with 111In-labelled chimeric B72.3 diethylenetriaminepentaacetic acid (DTPA) cyclic anhydride conjugate (cDTPA) and a C-linked derivative... |
7516417 | Interaction between CD44 and hyaluronate is directly implicated in the regulation of tumor development. | CD44 is implicated in the regulation of tumor growth and metastasis but the mechanism by which expression of different CD44 isoforms determines the rate of primary and secondary tumor growth remains unclear. In the present study we use a human melanoma transfected with wild-type and mutant forms of CD44 to determine wh... |
8005688 | Unique ability of the Proteus mirabilis capsule to enhance mineral growth in infectious urinary calculi. | Struvite (MgNH4PO4.6H2O) calculi are a common complication of Proteus mirabilis urinary tract infections. Although urease is a major virulence factor in calculus formation, the polysaccharide capsule (CPS) of this organism also enhances struvite crystallization and growth in vitro (L. Clapham, R. J. C. McLean, J. C. Ni... |
8005679 | Impairment of the cellular immune response in acute murine toxoplasmosis: regulation of interleukin 2 production and macrophage-mediated inhibitory effects. | Depression of the cellular immune response to Toxoplasma gondii has been reported in both mice and humans. The present study was undertaken to determine the kinetics and mechanism of the observed downregulation of interleukin 2 (IL-2) production during experimental murine toxoplasmosis. For these investigations, the ce... |
8207846 | Formation of empty B19 parvovirus capsids by the truncated minor capsid protein. | We previously reported that empty capsids of B19 parvovirus were formed by the major capsid protein (VP2) alone expressed in a baculovirus system, but the minor capsid protein (VP1), longer by 227 amino acids, alone did not form empty capsids. We report here further investigations of the constraints on capsid formation... |
8207841 | Changes in the cytopathic effects of human immunodeficiency virus type 1 associated with a single amino acid alteration in the ectodomain of the gp41 transmembrane glycoprotein. | A human immunodeficiency virus type 1 mutant with a single amino acid change (designated 596 W/M) in the ectodomain of the gp41 transmembrane envelope glycoprotein replicated in T-cell lines and in CD4-positive peripheral blood mononuclear cells identically to the wild-type virus. However, the cytopathic effects associ... |
8207829 | Reconstitution of Flock House provirions: a model system for studying structure and assembly. | Assembly of Flock House virus in infected Drosophila cells proceeds through an intermediate, the provirion, which lacks infectivity until the coat precursor protein, alpha, undergoes a spontaneous "maturation" cleavage (A. Schneemann, W. Zhong, T. M. Gallagher, and R. R. Rueckert, J. Virol 6:6728, 1992). We describe he... |
8207824 | Three-dimensional structure of vaccinia virus-produced human papillomavirus type 1 capsids. | The capsid proteins of papillomavirus self-assemble to form empty capsids or virus-like particles that appear quite similar to naturally occurring virions by conventional electron microscopy. To characterize such virus-like particles more fully, cryoelectron microscopy and image analysis techniques were used to generat... |
8207813 | Mutations in v-Src SH3 and catalytic domains that jointly confer temperature-sensitive transformation with minimal temperature-dependent changes in cellular tyrosine phosphorylation. | We have analyzed two functionally significant amino acid alterations encoded by the temperature-sensitive (ts) v-src mutant of Rous sarcoma virus, LA32. The G-to-V change at residue 300 in the catalytic domain nonconditionally impairs morphological transformation, in vitro kinase activity, in vivo tyrosine phosphorylat... |
8207801 | Inhibition of p53 DNA binding by human papillomavirus E6 proteins. | Transformation by the human papillomavirus (HPV) early gene products, E6 and E7, involves their interaction with cellular proteins p53 and Rb. Using glutathione S-transferase (GST) fusion proteins, we found that HPV E6 bound human p53 and that the relative efficiency of binding varied such that the GST-HPV type 16 E6 (... |
8207792 | Identification of sequence elements in the human cytomegalovirus DNA polymerase gene promoter required for activation by viral gene products. | To determine the mechanisms involved in the regulation of human cytomegalovirus early gene expression, we have examined the gene that encodes the viral DNA polymerase (UL54, pol). Our previous studies demonstrated that sequences required for activation of the pol promoter by immediate-early proteins are contained withi... |
8207791 | Alphaherpesvirus origin-binding protein homolog encoded by human herpesvirus 6B, a betaherpesvirus, binds to nucleotide sequences that are similar to ori regions of alphaherpesviruses. | We previously identified a human herpesvirus 6B (HHV-6B) homolog of the alphaherpesvirus origin-binding protein (OBP), exemplified by the herpes simplex virus type 1 UL9 gene product. This finding is of particular interest because HHV-6B is otherwise more closely related to members of the betaherpesvirus subfamily. The... |
24310029 | On the structure of bacteriochlorophyll molecular aggregates in the chlorosomes of green bacteria. A molecular modelling study. | The supramolecular structure of methyl (3(1) R)-BChlided aggregation has been explored by molecular modelling in order to elucidate the unusual structure of the BChl rods in the chlorosomal antennae of green bacteria. The aggregate construction progressed from a BChlide monomer in 5c coordination which was stepwise com... |
24221966 | Evidence for the direct desorption of crown ether-metal ion complexes in liquid secondary Ionization Mass Spectrometry. | The liquid secondary ionization mass spectra of crown ether solutions and crown ether solutions containing alkali metal cations were generated. Cesium cations acted as both the primary ion beam and as a competing gas-selvedge-phase reactant. The data suggest that crown ether complexes formed in the condensed phase surv... |
17750666 | "Molecule corrals" for studies of monolayer organic films. | Scanning tunneling microscopy (STM) studies have demonstrated that monolayer-deep, flat-bottomed, circular etch pits can be grown on highly ordered pyrolytic graphite by high-temperature etching in the presence of oxygen. In this work, these graphite etch pits are used as "molecule corrals" to isolate ensembles of mole... |
16349334 | Utilization of light for nitrogen fixation by a new synechocystis strain is extended by its low photosynthetic efficiency. | Performance of photosynthesis and nitrogenase activity in a novel cyanobacterium, Synechocystis sp. strain BO 8402, isolated from Lake Constance, located at the northern fringe of the Alps in central Europe, and of a stable derivative, strain BO 9201, were examined. Strain BO 8402 is characterized by an extraordinarily... |
7826679 | Design of molecules that specifically recognize and cleave apurinic sites in DNA. | We have prepared a series of tailor-made molecules that recognize and cleave DNA at apurinic sites in vitro. These molecules incorporate in their structure different units designed for specific function: an intercalator for DNA binding, a nucleic base for abasic site recognition and a linking chain of variable length a... |
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