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8694779 | Ligand selectivity of 105 kDa and 130 kDa lipoprotein-binding proteins in vascular-smooth-muscle-cell membranes is unique. | Using ligand blotting techniques, with low-density lipoprotein (LDL) as ligand, we have previously described the existence of atypical lipoprotein-binding proteins (105 kDa and 130 kDa) in membranes from human aortic medical tissue. The present study demonstrates that these proteins are also present in membranes from c... |
8694773 | Flavinylation in wild-type trimethylamine dehydrogenase and differentially charged mutant enzymes: a study of the protein environment around the N1 of the flavin isoalloxazine. | In wild-type trimethylamine dehydrogenase, residue Arg-222 is positioned close to the isoalloxazine N1/C2 positions of the 6S-cysteinyl FMN. The positively charged guanidino group of Arg-222 is thought to stabilize negative charge as it develops at the N1 position of the flavin during flavinylation of the enzyme. Three... |
9027219 | Mixed potential response mechanism of cobalt electrodes toward inorganic phosphate. | The potentiometric response mechanism of a previously reported phosphate ion-sensitive electrode based on a surface-oxidized cobalt metal is examined. Beyond response to phosphate, the cobalt electrode is found to respond to changes in the partial pressure of oxygen in the sample solution. the potentiometric response t... |
8673931 | Light activatable antibodies: models for remotely activatable proteins. | The ability to activate biological macromolecules remotely, at specific locations and times, will allow the manipulation of a wide range of cellular activities and give rise to many practical applications. Interest has been shown in the theoretical possibility of accomplishing this by means of photochemical approaches.... |
8679637 | Distinct molecular recognition of calmodulin-binding sites in the neuronal and macrophage nitric oxide synthases: a surface plasmon resonance study. | The neuronal nitric oxide synthase and the macrophage nitric oxide synthase are differently regulated by Ca2+/calmodulin. We investigated the dynamics of calmodulin binding to the putative calmodulin-binding sites in both nitric oxide synthases. Peptides derived from the putative calmodulin-binding sites were synthesiz... |
8674063 | Processing of antibodies bound to B-cell lymphomas and other hematological malignancies. | In an attempt to recognize general patterns in the processing of Abs (antibodies) bound to the surface of tumor cells, eight monoclonal antibodies were tested on 10 hematological malignancies of various histological types. The results were compared with previous findings obtained with carcinomas, melanomas, and gliomas... |
8676500 | The polymerase-like core of brome mosaic virus 2a protein, lacking a region interacting with viral 1a protein in vitro, maintains activity and 1a selectivity in RNA replication. | Brome mosaic virus (BMV), a member of the alphavirus-like super-family of positive-strand RNA viruses, encodes two proteins required for viral RNA replication: 1a and 2a. 1a contains m7G methyltransferase- and helicase-like domains, while 2a contains a polymerase (pol)-like core flanked by N- and C-terminal extensions.... |
8676498 | Cellular factors controlling the activity of woodchuck hepatitis virus enhancer II. | Woodchuck hepatitis virus (WHV) efficiently induces hepatocellular carcinoma in chronically infected hosts. A key step in hepatocarcinogenesis by WHV is insertional activation of the cellular N-myc gene by integrated viral DNA. WHV enhancer II (En II) is the major cis-acting element involved in this activation. Here we... |
8676444 | Identification and characterization of a double-stranded RNA- reovirus temperature-sensitive mutant defective in minor core protein mu2. | A newly identified temperature-sensitive mutant whose defect was mapped to the reovirus M1 gene (minor core protein mu2) was studied to better understand the functions of this virion protein. Sequence determination of the Ml gene of this mutant (tsH11.2) revealed a predicted methionine-to-threonine alteration at amino ... |
8668180 | Signaling in the yeast pheromone response pathway: specific and high-affinity interaction of the mitogen-activated protein (MAP) kinases Kss1 and Fus3 with the upstream MAP kinase kinase Ste7. | Kss1 and Fus3 are mitogen-activated protein kinases (MAPKs or ERKs), and Ste7 is their activating MAPK/ERK kinase (MEK), in the pheromone response pathway of Saccharomyces cerevisiae. To investigate the potential role of specific interactions between these enzymes during signaling, their ability to associate with each ... |
24271479 | Manipulation of the bacteriochlorophyll c homolog distribution in the green sulfur bacterium Chlorobium tepidum. | We have shown that the green sulfur bacterium Chlorobium tepidum can be grown in batch culture supplemented with potentially toxic fatty alcohols without a major effect on the growth rate if the concentration of the alcohols is kept low either by programmed addition or by adding the alcohol as an inclusion complex with... |
11667335 | Remarkably Selective Ag(+) Extraction and Transport by Thiolariat Ethers. | Synthesis and metal binding properties of thiolariat ethers, where a sulfide side chain is introduced into a framework of a crown ether, have been performed. Remarkably high Ag(+) selectivity among heavy metal ions was observed in solvent extraction and transport across a liquid membrane using thiolariat ethers with a ... |
11667324 | Synthesis, Structure, and Reactivity of Enediyne Macrocycles. | The reaction of bis-propargyl bromide enediyne 4 with weakly basic nucleophiles allows the facile synthesis of acyclic and macrocyclic enediynes. Depending on the bis-nucleophile employed, 12- to 16-membered enediyne macrocycles were obtained. The thermal stability of the new cyclic enediynes was investigated by differ... |
11666587 | Mono- and Dinuclear Transition Metal Complexes of the Hexadentate Ligand Tris(4-tert-butyl-2-mercaptobenzyl)-1,4,7-triazacyclononane (L). | The hexadentate, pendant arm macrocycle 1,4,7-tris(4-tert-butyl-2-mercaptobenzyl)-1,4,7-triazacyclononane (H(3)L) has been synthesized and isolated as its trihydrochloride, H(3)L.3HCl, or sodium salt, Na(3)L, and its coordination chemistry with first-row transition metals has been studied. Mononuclear complexes of the ... |
11666570 | Stability and Structure of Activated Macrocycles. Ligands with Biological Applications. | Single p-toluic acid pendant groups were attached to 1,4,7,10,13-pentaazacyclopentadecane (15aneN5) and 1,4,8,11-tetraazacyclotetradecane (cyclam) to prepare bifunctional reagents for radiolabeling monoclonal antibodies with (64,67)Cu. The ligands are 1,4,7,10,13-pentaazacyclopentadecane-1-(alpha-1,4-toluic acid) (PCBA... |
8881284 | Pulse exposure to ionizing radiation elicits rapid changes in cellular radiosensitivity. | A linear electron accelerator, operated in a recurrent chopped mode, was used for time-resolved investigation of split-dose radiation recovery in 3 mammalian cell lines in vitro. The time intervals separating the sequential radiation exposures in this study ranged from fractions of a second to a few minutes. The primar... |
8832501 | The influence of 2-hydroxypropyl-beta-cyclodextrin on the haemolysis induced by bile acids. | Cyclodextrins improve the water-solubility of drugs and can mask their haemolytic effect in parenteral use. Because the mechanism by which bile acids induce haemolysis is poorly understood, it has been investigated in the presence of 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CyD). The haemolytic effect of 1.8 mM solut... |
8832437 | Detection of basal acetylcholine release in the microdialysis of rat frontal cortex by high-performance liquid chromatography using a horseradish peroxidase-osmium redox polymer electrode with pre-enzyme reactor. | To determine the basal acetylcholine level in the dialysate of rat frontal cortex, a horseradish peroxidase-osmium redox polymer-modified glassy carbon electrode (HRP-GCE) was employed instead of the conventional platinum electrode used in high-performance liquid chromatography-electrochemical detection (HPLC-ED). In i... |
8818049 | The influence of temperature on the high performance liquid chromatographic separation of steroids using mobile phases modified with beta-cyclodextrin. | The effect of temperature on the retention and multiple separation of hydrocortisone, testosterone, 17 alpha-methyltestosterone, prednisone, cortisone and 17 alpha-hydroxyprogesterone in reversed-phase liquid chromatography has been studied. Capacity factors (k') of the steroids were measured using a mobile phase modif... |
8818022 | Resolution improvement by use of carboxymethyl-beta-cyclodextrin as chiral additive for the enantiomeric separation of basic drugs by capillary electrophoresis. | Three beta-cyclodextrin derivatives--carboxymethyl-, dimethyl- and hydroxypropyl-beta-cyclodextrin--were tested as chiral selectors for the enantioseparation of seven basic drugs in free solution capillary electrophoresis, using buffers made of 100 mM phosphoric acid adjusted to pH 3.0 with triethanolamine in fused sil... |
8818019 | Capillary electrophoretic enantioseparation of selegiline, methamphetamine and ephedrine using a neutral beta-cyclodextrin epichlorhydrin polymer. | This paper describes the development of a capillary zone electrophoretic method for chiral separation of three basic compounds of the selegiline synthetic pathway: ephedrine, methamphetamine and selegiline. The method developed allows one to separate the studied compounds in one run using a neutral beta-cyclodextrin ep... |
8818001 | Use of micellar media for the fluorimetric determination of ellipticine in aqueous solutions. | Ellipticine is a pyridocarbazole alkaloid with interesting antitumour activity. Use of neutral ellipticine is hampered by its very low water solubility and therefore this compound has been administered as a salt; however, nitrogen quaternization modifies the antitumour properties of ellipticine. Potential alternatives ... |
8817995 | Analytical applications of retinoid-cyclodextrin inclusion complexes. 1. Characterization of a retinal-beta-cyclodextrin complex. | In studies in these laboratories on the supramolecular chemistry of the retinoids, it has been recently confirmed that inclusion of these substances within the cavity of cyclodextrins protects their excited states, thus improving their photochemical stability. In the present paper, the isolation is described of a cryst... |
8817994 | Analytical strategies for the measurement of lithium in biological samples. | Therapeutic lithium levels in the treatment of manic depressive psychosis must be maintained in the range of 0.5-1.5 mM in the blood, which also contains 140 mM sodium. This paper reviews spectrophotometric, fluorometric, and ion-selective electrode (ISE) reagents and methods for achieving high lithium selectivity over... |
8817986 | Experiences of postcardiotomy assist: pneumatic ventricular assist device or venoarterial bypass with percutaneous cardiopulmonary support. | From October 1982 to the present, 16 patients have been supported by a pneumatic ventricular assist device (VAD). Since April 1990, we have introduced a venoarterial bypass (VAB) with percutaneous cardiopulmonary support (PCPS) system. This PCPS system was used in 12 patients. The long-term survival rate of PCPS cases ... |
8817074 | Ribosomal DNA is frequently concentrated on only one X chromosome in permanently apomictic aphids, but this does not inhibit male determination. | The ribosomal DNA arrays in the nucleolar organizer regions (NORs) of aphids are generally-located in a telomeric or subtelomeric position on the X chromosomes. In aphid populations or species that have lost the sexual part of their life cycle and become permanent apomicts, multiple rDNA copies are often concentrated o... |
8817073 | Mapping of a new MAP kinase activated protein kinase gene (3PK) to human chromosome band 3p21.2 and ordering of 3PK and two cosmid markers in the 3p22-p21 tumour-suppressor region by two-colour fluorescence in situ hybridization. | A Noti-linking clone NL1-210 (D3S1656) that contains the human MAP kinase activated protein kinase (3PK) gene was localized to 3p21.2 on DAPI-banded and propidium iodide (R-bands)-stained chromosomes by fluorescence in situ hybridization (FISH). For more precise localization of 3PK, two cosmid probes were used as a fra... |
8817072 | Report on the progress of standardization of the G-banded canine (Canis familiaris) karyotype. Committee for the Standardized Karyotype of the Dog (Canis familiaris). | Karyotyping of dog chromosomes is a difficult task owing to the high diploid number of chromosomes (2n = 78) and the similar morphology of autosomes, all of which are acrocentrics. In this report 22 of the 39 G-banded chromosome pairs and their corresponding ideograms have been standardized. The ideogram comprises alto... |
8817071 | Fluorescence in situ hybridization with rDNA probes on chromosomes of two nucleolus organizer region phenotypes of a species of Eigenmannia (Pisces, Gymnotoidei, Sternopygidae). | Nucleolus organizer regions (NORs) were analysed in two related and geographically close populations of Eigenmannia sp.1 (Pisces, Gymnotoidei, Sternopygidae) using silver staining and fluorescence in situ hybridization (FISH). The two populations differed in their Ag-NOR phenotypes, displaying fixed differences in the ... |
8817070 | The human/mouse imprinted genes IGF2, H19, SNRPN and ZNF127 map to two conserved autosomal clusters in a marsupial. | The four genes IGF2, H19, SNRPN and ZNF127 are imprinted in mouse and human. IGF2 and H19 form one conserved cluster on the distal part of mouse chromosome 7 and human chromosome 11p15.5, whereas SNRPN and ZNF127 form another on the middle of mouse chromosome 7 and on human chromosome 15q11-13. We have explored the evo... |
8817069 | Changes in chromosomal ultrastructure during the cell cycle. | The surface structure of mitotic barley and rye chromosomes was studied by high-resolution scanning electron microscopy. Chromosomes with various degrees of chromatin condensation were prepared from untreated meristematic tissue of root tips. At lower magnifications the highly condensed chromosomes in metaphase and ana... |
8817068 | Distribution and linkage of repetitive clusters from the heterochromatic region of human chromosome 22. | The pericentric regions of eukaryotic chromosomes consist of several types of repetitive DNA families. In human chromosome 22, the organization of such families was studied in more detail. In addition to the known families of alpha and beta repeats, an additional repeat with a 48-bp motif was previously assigned to 22p... |
8817067 | In situ localization of yeast artificial chromosome sequences on tomato and potato metaphase chromosomes. | In situ localization of short low- or single-copy sequences is still difficult in plants. One solution to this problem could be the use of large yeast artificial chromosomes (YACs) for fluorescence in situ hybridization. Two YACs specific for a single copy marker on the long arm of the NOR-chromosome 2 of tomato (Lycop... |
8817066 | Cytological evidence for 5-azacytidine-induced demethylation of the heterochromatic regions of human chromosomes. | This work was aimed at studying the effects of the demethylating agent 5-azacytidine (5-azaC) on the constitutive heterochromatin of human chromosomes at the cytological level. Metaphase preparations from peripheral blood lymphocyte and lymphoblastoid cultures obtained by standard methods were treated with the agent. L... |
8817065 | Chromosome painting defines genomic rearrangements between red howler monkey subspecies. | We hybridized whole human chromosome-specific DNA libraries to chromosomes of two supposed subspecies of Alouatta seniculus: Alouatta seniculus sara and Alouatta seniculus arctoides. The number of hybridization signals per haploid set is 42 in A. s. sara and 43 in A. s. arctoidea; the two karyotypes differ by at least ... |
8817064 | Fluorescence lifetime imaging: an emerging technique in fluorescence microscopy. | Fluorescence microscopy is an important tool for biological research, in part because of the extremely high detection sensitivity that can be achieved, but also because fluorescent molecules can be used as probes on account of their environmental responsiveness, for example to measure intracellular pH or metal ion conc... |
8816999 | Overexpression of cytoplasmic dynein's globular head causes a collapse of the interphase microtubule network in Dictyostelium. | Cytoplasmic dynein is a minus-end directed microtubule-based motor. Using a molecular genetic approach, we have begun to dissect structure-function relationships of dynein in the cellular slime mold Dictyostelium. Expression of a carboxy-terminal 380-kDa fragment of the heavy chain produces a protein that approximates ... |
8811433 | Optimization of the separation and detection of the enantiomers of isoproterenol in microdialysis samples by cyclodextrin-modified capillary electrophoresis using electrochemical detection. | Isoproterenol is a chiral catecholamine with a half-life of elimination of less than 10 min. In order to study the pharmacokinetics of this compound using microdialysis sampling, an analytical method was needed which could resolve the individual enantiomers of isoproterenol and required less than 1 microliter of sample... |
8809757 | The ndh-binding protein (Nbp) regulates the ndh gene of Escherichia coli in response to growth phase and is identical to Fis. | The ndh gene that encodes the non-proton-translocating NADH dehydrogenase II of Escherichia coli is anaerobically repressed by FNR. However, in the absence of FNR, ndh expression is enhanced by anaerobic growth in media containing amino acids. Two potential regulatory proteins that may be associated with this activatio... |
8808738 | Synthesis and conformational analysis by 1H NMR and restrained molecular dynamics simulations of the cyclic decapeptide [Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly]. | The design of enzyme mimics with therapeutic and industrial applications has interested both experimental and computational chemists for several decades. Recent advances in the computational methodology of restrained molecular dynamics, used in conjunction with data obtained from two-dimensional 1H NMR spectroscopy, ma... |
8804830 | In vitro selection of aptamers: the dearth of pure reason. | In vitro selection experiments are now routinely used to identify functional nucleic acid residues and structures, and have become a tool for studying molecular recognition, molecular biology, and molecular evolution. Technical innovations that have been made during the past year include the use of modified monomers to... |
8799566 | Involvement of nitric oxide and eicosanoids in platelet-activating factor-induced haemodynamic and haematological effects in dogs. | 1. Platelet-activating factor (PAF) is a phospholipid mediator with potent cardiovascular and haematological actions. But its mechanisms of action in vivo have not been fully elucidated, probably due to difficulties arising from previous findings that the effects of PAF are largely mediated by the release of a variety ... |
8799371 | Sequence-specific detection of PCR-amplified DNA by restriction enzyme release of hybrids. | We have developed a method to detect PCR amplicons that contain a restriction enzyme site. The method is called Polymerase Chain Reaction-Hybridization and Enzymatic Release Assay (PCR-HERA). The PCR product is hybridized to a synthetic oligonucleotide that is immobilized on a microtitre plate. Specific cleavage of the... |
8799295 | Investigation of porphyrins and metalloporphyrins using two-step laser mass spectrometry. | Laser desorption time-of-flight mass spectrometry with laser postionization at 193 nm has been used to study a series of selected porphyrins and metalloporphyrins. Molecular ions are predominantly formed under soft ionization conditions, with extensive fragmentation of the peripheral substituents being observed under h... |
8781724 | Clinical significance of the alterations of plasma prostaglandin E2 (PGE2) in severely burned patients. | Agar gel single diffusion and radio immunological analyses were employed to determine the levels of serum C3c, C4, IgA, IgM, IgG and plasma PGE2 in 24 severely burned patients. The results were compared with the development of postburn immunosuppression, severe infection and MOF. There were marked decreases in serum C3... |
8781723 | Clinical significance of the changes in serum fibronectin in severely burned patients. | The Agar gel single diffusion technique was used to investigate the changes in serum fibronectin (FN) in severely burned patients, and coupled with the study of simultaneous changes in the internal organ function, the development of MOF and severe systemic infection. The results suggested that the deficiency or decreas... |
8773301 | Cell surface chondroitin sulfate proteoglycans in tumor cell adhesion, motility and invasion. | Tumor cell invasion and metastasis is highly dependent on dynamic changes in the adhesion and migration of transformed and malignant cells. As with normal cell adhesion, the adhesion of tumor cells influences their cytoskeletal organization, activation of signal transduction pathways within the cell, and nuclear events... |
8744324 | Measurement of intercolumnar forces between parallel guanosine four-stranded helices. | The deoxyguanosine-5'-monophosphate in aqueous solution self-associates into stable structures, which include hexagonal and cholesteric columnar phases. The structural unit is a four-stranded helix, composed of a stacked array of Hoogsteen-bonded guanosine quartets. We have measured by osmotic stress method the force p... |
8744311 | The interfacial structure of phospholipid bilayers: differential scanning calorimetry and Fourier transform infrared spectroscopic studies of 1,2-dipalmitoyl-sn-glycero-3-phosphorylcholine and its dialkyl and acyl-alkyl analogs. | The thermotropic phase behavior of aqueous dispersions of dipalmitoylphosphatidylcholine (DPPC) and its 1,2-dialkyl, 1-acyl 2-alkyl and 1-alkyl 2-acyl analogs was examined by differential scanning calorimetry, and the organization of these molecules in those hydrated bilayers was studied by Fourier transform infrared s... |
8744306 | Identification of cystic fibrosis transmembrane conductance regulator channel-lining residues in and flanking the M6 membrane-spanning segment. | The cystic fibrosis transmembrane conductance regulator (CFTR) forms a chloride channel that is regulated by phosphorylation and ATP binding. Work by others suggested that some residues in the sixth transmembrane segment (M6) might be exposed in the channel and play a role in ion conduction and selectivity. To identify... |
8762150 | Tumor marker disaccharide D-Gal-beta 1, 3-GalNAc complexed to heat-labile enterotoxin from Escherichia coli. | Heat-labile enterotoxin (LT) is part of the cholera toxin (CT) family and consists of a catalytic A subunit and a B pentamer that serves to recognize the oligosaccharide part of the GM1 ganglioside receptor. We report here the crystal structure of heat-labile enterotoxin in complex with the disaccharide portion of the ... |
8762144 | Invariant glycines and prolines flanking in loops the strand beta 2 of various (alpha/beta)8-barrel enzymes: a hidden homology? | The question of parallel (alpha/beta)8-barrel fold evolution remains unclear, owing mainly to the lack of sequence homology throughout the amino acid sequences of (alpha/beta)8-barrel enzymes. The "classical" approaches used in the search for homologies among (alpha/beta)8-barrels (e.g., production of structurally base... |
8762131 | Protein folding for realists: a timeless phenomenon. | Future research on protein folding must confront two serious dilemmas. (1) It may never be possible to observe at high resolution the very important structures that form in the first few milliseconds of the refolding reaction. (2) The energy functions used to predict structure from sequence will always be approximation... |
8766208 | Isolation by HPLC of the positional isomers of heterogeneous doubly branched cyclomaltohexaose having one alpha-D-galactosyl and one alpha-D-glucosyl side chain and determination of their structures by enzymatic degradation. | Each of the six and five positional isomers of 2n- and 6n-O-alpha-D-galactopyranosyl-6(1)-O-alpha-D-glucopyranosyl-cyclomalt ohexaose (alpha-cyclodextrin, alpha CD; 2n: n = 1-6, 6n: n = 2-6), which were produced from 6-O-alpha-D-glucopyranosyl-alpha CD and melibiose by transgalactosylation with coffee bean alpha-galact... |
8766204 | Analysis of charged cyclomalto-oligosaccharides (cyclodextrin) derivatives by ion-spray, matrix-assisted laser-desorption/ionization time-of-flight and fast-atom bombardment mass spectrometry, and by capillary electrophoresis. | The use of electrospray-ionization mass spectrometry (ESIMS), matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDITOFMS), and fast-atom bombardment mass spectrometry (FABMS) for the rapid determination of molecular weight, degree of substitution (ds), and purity is demonstrated for charge... |
8753088 | [Significance of systemic inflammatory response syndrome at cardiopulmonary bypass]. | Systemic Inflammatory Response Syndrome (SIRS) is a new concept of entry criteria for sepsis. This concept, when applied to area of Multiple Organ Failure (MOF), is considered to be a preparatory state for MOF. To study the significance of SIRS state at cardiac surgery, we measured the body temperature, white blood cel... |
8682865 | Actin organization, bristle morphology, and viability are affected by actin capping protein mutations in Drosophila. | Regulation of actin filament length and orientation is important in many actin-based cellular processes. This regulation is postulated to occur through the action of actin-binding proteins. Many actin-binding proteins that modify actin in vitro have been identified, but in many cases, it is not known if this activity i... |
8682861 | The synaptic vesicle cycle: a single vesicle budding step involving clathrin and dynamin. | Strong evidence implicates clathrin-coated vesicles and endosome-like vacuoles in the reformation of synaptic vesicles after exocytosis, and it is generally assumed that these vacuoles represent a traffic station downstream from clathrin-coated vesicles. To gain insight into the mechanisms of synaptic vesicle budding f... |
8676064 | Molecular cloning and characterization of a human eotaxin receptor expressed selectively on eosinophils. | The chemokine eotaxin is unusual in that it appears to be a highly specific chemoattractant for eosinophils. Ligand-binding studies with radiolabeled eotaxin demonstrated a receptor on eosinophils distinct from the known chemokine receptors CKR-1 and -2. The distinct eotaxin binding site on human eosinophils also bound... |
8710502 | Stabilization of triple-stranded oligonucleotide complexes: use of probes containing alternating phosphodiester and stereo-uniform cationic phosphoramidate linkages. | Pyrimidine oligonucleotides containing alternating anionic and stereo-uniform cationic N-(dimethylamino-propyl)phosphoramidate linkages [e.g. d(T+T-)7T, d(T+T-)2(T+C-)5T and (U'+U'-)7dT, where U' is 2'-O-methyluridine)] are shown to bind to complementary double-stranded DNA segments in 0.1 M NaCl at pH 7 to form triple... |
8710497 | Characterization of proteolytic fragments of bacteriophage T7 DNA ligase. | Treatment of T7 DNA ligase with a range of proteases generates two major fragments which are resistant to further digestion. These fragments, of molecular weight 16 and 26 kDa, are derived from the N- and C-termini of the protein, respectively. The presence of ATP or a non-hydrolysable analogue, ADPNP, during limited p... |
8662997 | Assembly in vitro of thin and thick fibrils of collagen II from recombinant procollagen II. The monomers in the tips of thick fibrils have the opposite orientation from monomers in the growing tips of collagen I fibrils. | Human type II procollagen was prepared in a recombinant system and cleaved to pC-collagen II by procollagen N-proteinase. The pC-collagen II was then used as a substrate to generate collagen II fibrils by cleavage with procollagen C-proteinase at 37 degrees C. Electron microscopy of the fibrils demonstrated that, at th... |
8662820 | The contributions of aspartyl residues in the acetylcholine receptor gamma and delta subunits to the binding of agonists and competitive antagonists. | The acetylcholine (ACh) receptors in muscle have the composition alpha2betagammadelta and contain two ACh binding sites. One is formed between an alpha subunit and the gamma subunit, and the other is formed between an alpha subunit and the delta subunit. Among the residues in the ACh binding sites are alphaCys-192 and ... |
8683574 | Self-assembly of the filament capping protein, FliD, of bacterial flagella into an annular structure. | A bacterial flagellum has a cap structure at the tip of the external filament. The cap is composed of the FliD protein (Mr, 49 x 10(3)), and plays an essential role in the polymerization of the filament protein, flagellin, which is believed to be transported through a central channel in the flagellum. A fliD-deficient ... |
8670817 | The structure and function of the replication terminator protein of Bacillus subtilis: identification of the 'winged helix' DNA-binding domain. | The replication terminator protein (RTP) of Bacillus subtilis impedes replication fork movement in a polar mode upon binding as two interacting dimers to each of the replication termini. The mode of interaction of RTP with the terminus DNA is of considerable mechanistic significance because the DNA-protein complex not ... |
8670806 | The 'destruction box' of cyclin A allows B-type cyclins to be ubiquitinated, but not efficiently destroyed. | The destruction of mitotic cyclins by programmed proteolysis at the end of mitosis is an important element in cell cycle control. This proteolysis depends on a conserved motif of nine residues known as the 'destruction box', which is located 40-50 residues from the N-terminus. The sequences of the A- and B-type destruc... |
8692865 | Gadolinium(III) texaphyrin: a tumor selective radiation sensitizer that is detectable by MRI. | Gadolinium(III) texaphyrin (Gd-tex2+) is representative of a new class of radiation sensitizers detectable by magnetic resonance imaging (MRI). This porphyrin-like complex has a high electron affinity [E1/2 (red.) approximately = -0.08 V versus normal hydrogen electrode] and forms a long-lived pi-radical cation upon ex... |
8692863 | Deciphering the mechanism for the assembly of aromatic polyketides by a bacterial polyketide synthase. | Aromatic polyketides are assembled by a type 11 (iterative) polyketide synthase (PKS) in bacteria. Understanding the enzymology of such enzymes should provide the information needed for the synthesis of novel polyketides through the genetic engineering of PKSs. Using a previously described cell-free system [B.S. & C.R.... |
8692856 | Nucleator-dependent intercellular assembly of adhesive curli organelles in Escherichia coli. | Bacterial adhesion to other bacteria, to eukaryotic cells, and to extracellular matrix proteins is frequently mediated by cell surface-associated polymers (fimbriae) consisting of one or more subunit proteins. We have found that polymerization of curlin to fimbriae-like structures (curli) on the surface of Escherichia ... |
8683599 | Solution structure of the granular starch binding domain of glucoamylase from Aspergillus niger by nuclear magnetic resonance spectroscopy. | The solution structure of the granular starch binding domain (SBD) of glucoamylase 1 from Aspergillus niger has been determined by heteronuclear multidimensional nuclear magnetic resonance spectroscopy and simulated annealing. A total of 1092 nuclear Overhauser enhancement-derived 1H-1H distance constraints, 137 dihedr... |
8672506 | Cyclodextrin-mediated removal of sterols from monolayers: effects of sterol structure and phospholipids on desorption rate. | In this study, we have examined a number of parameters which affect the rate of sterol desorption from a model membrane surface (a monolayer at the air/water interface) to cyclodextrins (CD) in the aqueous subphase. The desorption experiments were carried out at a constant lateral surface pressure with a zero-order tro... |
8672493 | Two novel alpha-neurotoxins isolated from the taipan snake, Oxyuranus scutellatus, exhibit reduced affinity for nicotinic acetylcholine receptors in brain and skeletal muscle. | Three novel toxic peptides were purified to homogeneity from the venom of the Australian taipan snake, Oxyuranus scutellatus scutellatus. On the basis of complete amino acid sequence analyses, two of these toxins belong to the family of short-chain alpha-neurotoxins found in elapid and hydrophid snake venoms and are th... |
8664115 | Distribution and photodynamic effects of meso-tetrahydroxyphenylchlorin (mTHPC) in the pancreas and adjacent tissues in the Syrian golden hamster. | Photodynamic therapy (PDT) has the potential to destroy small tumours with safe healing of adjacent normal tissue. This study looks at the effects of PDT on the normal pancreas and adjacent tissues in hamsters using the photosensitiser meso-tetrahydroxyphenylchlorin (mTHPC). Pharmacokinetic studies used fluorescence mi... |
8801441 | Methanotrophic bacteria. | Methane-utilizing bacteria (methanotrophs) are a diverse group of gram-negative bacteria that are related to other members of the Proteobacteria. These bacteria are classified into three groups based on the pathways used for assimilation of formaldehyde, the major source of cell carbon, and other physiological and morp... |
8801434 | Molecular and industrial aspects of glucose isomerase. | Glucose isomerase (GI) (D-xylose ketol-isomerase; EC. 5.3.1.5) catalyzes the reversible isomerization of D-glucose and D-xylose to D-fructose and D-xylulose, respectively. The enzyme has the largest market in the food industry because of its application in the production of high-fructose corn syrup (HFCS). HFCS, an equ... |
8691424 | Synthesis and biological activities of flavonoid derivatives as A3 adenosine receptor antagonists. | A broad screening of phytochemicals has demonstrated that certain flavone and flavonol derivatives have a relatively high affinity at A3 adenosine receptors, with Ki values of > or = 1 microM (Ji et al. J. Med. Chem. 1996, 39, 781-788). We have further modified the flavone structure to achieve a degree of selectivity f... |
8675693 | Hypertension-associated point mutations in the adducin alpha and beta subunits affect actin cytoskeleton and ion transport. | The adducin heterodimer is a protein affecting the assembly of the actin-based cytoskeleton. Point mutations in rat adducin alpha (F316Y) and beta (Q529R) subunits are involved in a form of rat primary hypertension (MHS) associated with faster kidney tubular ion transport. A role for adducin in human primary hypertensi... |
8687394 | Modulation of flavocytochrome b2 intraprotein electron transfer via an interdomain hinge region. | The two domains of flavocytochrome b2 are connected by a typical hinge peptide. To probe the role of the hinge in modulating the efficiency of intraprotein electron transfer between these two domains, a number of mutant enzymes with truncated hinge regions were previously constructed and characterized [Sharp, Chapman a... |
8655563 | Modulation of development, growth dynamics, wall crystallinity, and infection sites in white clover root hairs by membrane chitolipooligosaccharides from Rhizobium leguminosarum biovar trifolii. | We used bright-field, time-lapse video, cross-polarized, phase-contrast, and fluorescence microscopies to examine the influence of isolated chitolipooligosaccharides (CLOSs) from wild-type Rhizobium leguminosarum bv. trifolii on development of white clover root hairs, and the role of these bioactive glycolipids in prim... |
8654385 | Structural adaptations in the interaction of EcoRI endonuclease with methylated GAATTC sites. | We have studied the interaction of EcoRI endonuclease with oligonucleotides containing GAATTC sites bearing one or two adenine-N6-methyl groups, which would be in steric conflict with key protein side chains involved in recognition and/or catalysis in the canonical complex. Single-strand methylation of either adenine p... |
8654382 | Variant minihelix RNAs reveal sequence-specific recognition of the helical tRNA(Ser) acceptor stem by E.coli seryl-tRNA synthetase. | Aminoacylation rate determinations for a series of variant RNA minihelix substrates revealed that Escherichia coli seryl-tRNA synthetase (SerRS) recognizes the 1--72 through 5--68 base pairs of the E.coli tRNA(Ser) acceptor stem with the major recognition elements clustered between positions 2--71 and 4--69. The rank o... |
8654358 | A pathogenic bacterium triggers epithelial signals to form a functional bacterial receptor that mediates actin pseudopod formation. | Enteropathogenic E. coli (EPEC) belongs to a group of bacterial pathogens that induce actin accumulation beneath adherent bacteria. We found that EPEC adherence to epithelial cells mediates the formation of fingerlike pseudopods (up to 10 microm) beneath bacteria. These actin-rich structures also contain tyrosine phosp... |
8666079 | Outbreaks of Norwalk-like virus-associated gastroenteritis traced to shellfish: coexistence of two genotypes in one specimen. | We determined the nucleotide sequences of Norwalk-like viruses in 10 PCR products from stool or oyster specimens obtained from four outbreaks of gastroenteritis in which shellfish was suspected as the cause in Shizuoka prefecture in Japan between 1987-94. The sequences were determined from nucleotide positions 4561-485... |
8655588 | A GTPase distinct from Ran is involved in nuclear protein import. | Signal-dependent transport of proteins into the nucleus is a multi-step process mediated by nuclear pore complexes and cytosolic transport factors. One of the cytosolic factors, Ran, is the only GTPase that has a characterized role in the nuclear import pathway. We have used a mutant form of Ran with altered nucleotide... |
8668551 | Regulation of in vitro gene expression using antisense oligonucleotides or antisense expression plasmids transfected using starburst PAMAM dendrimers. | Starburst polyamidoamine (PAMAM) dendrimers are a new type of synthetic polymer characterized by a branched spherical shape and a high density surface charge. We have investigated the ability of these dendrimers to function as an effective delivery system for antisense oligonucleotides and 'antisense expression plasmid... |
8660912 | Interactions of human skin fibroblasts with monomeric or fibrillar collagens induce different organization of the cytoskeleton. | Fibrillar collagens represent the most abundant extracellular matrix components surrounding fibroblasts. Although there is a large heterogeneity in the collagen composition and in the physiological functions of different tissues, interactions between cells and native collagens monomers are mediated by only two integrin... |
8992510 | Lutetium texaphyrin (PCI-0123): a near-infrared, water-soluble photosensitizer. | Lutetium texaphyrin, PCI-0123, is a pure, water-soluble photosensitizer with a large broad absorption band centered at 732 nm. The compound was tested for photodynamic therapy (PDT) effectiveness in a murine mammary cancer model. The texaphyrin macrocycle as illustrated by magnetic resonance imaging and 14C-radiolabele... |
8655496 | Characterization of the cytoplasmic filament protein gene (cfpA) of Treponema pallidum subsp. pallidum. | Treponema pallidum and other members of the genera Treponema, Spirochaeta, and Leptonema contain multiple cytoplasmic filaments that run the length of the organism just underneath the cytoplasmic membrane. These cytoplasmic filaments have a ribbon-like profile and consist of a major cytoplasmic filament protein subunit... |
8650204 | Kinetics of self-assembling microtubules: an "inverse problem" in biochemistry. | Experimental time series for a nonequilibrium reaction may in some cases contain sufficient data to determine a unique kinetic model for the reaction by a systematic mathematical analysis. As an example, a kinetic model for the self-assembly of microtubules is derived here from turbidity time series for solutions in wh... |
8652792 | Discovering protein secondary structures: classification and description of isolated alpha-turns. | Irregular protein secondary structures are believed to be important structural domains involved in molecular recognition processes between proteins, in interactions between peptide substrates and receptors, and in protein folding. In these respects tight turns are being studied in detail. They also represent template s... |
8649408 | Differential control of transcription by homologous homeodomain coregulators. | The human herpes simplex virus type 1 (HSV-1) transactivator VP16 and its homolog from bovine herpes-virus 1 (BHV-1) can each recruit the human homeodomain protein Oct-1 into a transcriptional regulatory complex. Here, we show that these two Oct-1 coregulators possess similar, if not identical, homeodomain recognition ... |
8649400 | B-lymphocyte development is regulated by the combined dosage of three basic helix-loop-helix genes, E2A, E2-2, and HEB. | B-lymphocyte development requires the basic helix-loop-helix proteins encoded by the E2A gene. In this study, the control mechanism of E2A was further explored by disruption of the E2A-related genes, E2-2 and HEB. In contrast to E2A, E2-2 and HEB are not essential for the establishment of the B-cell lineage. However, b... |
8648759 | Evidence that replication of human neurotropic JC virus DNA in glial cells is regulated by the sequence-specific single-stranded DNA-binding protein Pur alpha. | Initiation of polyomavirus DNA replication in eukaryotic cells requires the participation of the viral early protein T antigen, cellular replication factors, and DNA polymerases. The human polyomavirus JC virus (JCV) is the etiologic agent of the fatal demyelinating disease progressive multifocal leukoencephalopathy in... |
8648722 | Human immunodeficiency virus type 1 replication is blocked prior to reverse transcription and integration in freshly isolated peripheral blood monocytes. | Peripheral blood monocytes are resistant to productive human immunodeficiency virus type 1 (HIV-1) infection in vitro immediately after isolation. No viral cDNA (either early or late transcripts) was detected by PCR in monocytes exposed to virus on the day of isolation. In contrast, in monocytes cultured for as little ... |
8648697 | Cellular or viral protein binding to a cytomegalovirus promoter transcription initiation site: effects on transcription. | We have previously shown that the IE2 protein of human cytomegalovirus (CMV) represses its own synthesis by binding to the major immediate-early promoter (M. P. Macias and M. F. Stinski, Proc. Natl. Acad. Sci. USA 90:707-711, 1993). The binding of a viral protein (IE2) and a cellular protein in the region of the transc... |
8648684 | An N-terminal deletion mutant of simian virus 40 (SV40) large T antigen oligomerizes incorrectly on SV40 DNA but retains the ability to bind to DNA polymerase alpha and replicate SV40 DNA in vitro. | A peptide encompassing the N-terminal 82 amino acids of simian virus 40 (SV40) large T antigen was previously shown to bind to the large subunit of DNA polymerase alpha-primase (I. Dornreiter, A. Höss, A. K. Arthur, and E. Fanning, EMBO J. 9:3329-3336, 1990). We report here that a mutant T antigen, T83-708, lacking res... |
8648672 | Folding, assembly, and intracellular trafficking of the human immunodeficiency virus type 1 envelope glycoprotein analyzed with monoclonal antibodies recognizing maturational intermediates. | Monoclonal antibodies (MAbs) that bind linear or conformational epitopes on monomeric or oligomeric human immunodeficiency virus type 1 (HIV-1) envelope glycoproteins were screened for their recognition of maturational intermediates. On the basis of reactivities with gp160 at different times after pulse-labeling, the M... |
8648670 | Targeting human immunodeficiency virus type 1 reverse transcriptase by intracellular expression of single-chain variable fragments to inhibit early stages of the viral life cycle. | Novel molecular approaches to inhibit human immunodeficiency virus type 1 (HIV-1) infection have received increasing attention because of the lack of effective antiviral drug therapies in vivo. We now demonstrate that cells can be intracellularly immunized by cytoplasmic expression of single-chain variable antibody fra... |
29178232 | Separation of Diastereomeric and Enantiomeric Alkyl Nitrates-Systematic Approach to Chiral Discrimination on Cyclodextrin LIPODEX-D. | High-resolution gas chromatographic separation of all diastereomeric monomethyl-substituted cyclohexyl nitrates is shown on a nonpolar methylpolysiloxane stationary phase, and the first application of this procedure to the environmental diastereomeric analysis of alkyl nitrates is presented. Two characteristic signals ... |
29178230 | Synthetic Cyclic Oligosaccharides-Syntheses and Structural Properties of a Cyclo[(1 → 4)-α-L-rhamnopyranosyl-(1 → 4)-α-D-mannopyranosyl]trioside and -tetraoside. | An efficient polycondensation-cyclization approach to the synthesis of cyclodextrin analogues is demonstrated by the preparation of cyclohexaoside 1 and cyclooctaoside 2. The key intermediate, disaccharide 3, bearing the cyanoethylidene group as a glycosyl donor function and the trityloxy group as a glycosyl acceptor f... |
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