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3067426 | [Circular replicating baculovirus genome]. | Free Malacosoma neustria nuclear polyhedrosis virus preparations contain nucleocapsids typical of Baculoviruses' morphology and size as well as long virus-like particles. Viral DNA is circular and covalently closed. Its preparations contain rings with single-stranded breaks, catenanes and circular dimers as well. Repli... |
3226402 | [Expanding the surgical indication to the cases with high risk valve diseases]. | Four hundred and fifty eight cases of valve surgery were performed at this institution over the past 7 years, during which the surgical indication has been gradually expanded to cases of three types. The first type is serious disease complicated by cardiac cachexia; in these cases, in addition to the aggressive use of ... |
3225300 | Effect of the content of divinylbenzene in ion-exchange resins on the chromatographic separation of alpha-cyclodextrin and glucose. | In the chromatographic separation of alpha-cyclodextrin and glucose, the parameters relating to the adsorption equilibria and rate processes of the solutes were evaluated for the sodium forms of cation-exchange resins with contents of divinylbenzene (DVB) of 2, 4, 6 and 8%. By using these parameters, the chromatograms ... |
3224359 | Casein kinases I and II bound to pig brain microtubules. | 1. Microtubules prepared from pig brain by two cycles of assembly-disassembly comprise cyclic nucleotide-independent protein kinase activity with phosvitin and troponin T as substrates. 2. Phosphocellulose chromatography resolved two phosvitin kinase activity peaks, one of which coincided with the troponin T kinase pea... |
3146691 | Cysteine residues in the zinc finger and amino acids adjacent to the finger are necessary for DNA binding by the LAC9 regulatory protein of Kluyveromyces lactis. | LAC9 is a positive regulatory protein that controls transcription of the lactose-galactose regulon in Kluyveromyces lactis. LAC9 is homologous to the GAL4 protein of Saccharomyces cerevisiae. Both proteins have a single "zinc finger" which plays a role in DNA binding. We previously hypothesized (L. V. Wray, M. M. Witte... |
2462930 | TI-205 nuclear magnetic resonance determination of the thermodynamic parameters for the binding of monovalent cations to gramicidins A and C. | Thermodynamic parameters for the binding of the monovalent cations, Li+, Na+, K+, Rb+, Cs+, NH4+, TI+, and Ag+, to gramicidin A and for the binding of TI+ to gramicidin C, incorporated into lysophosphatidylcholine, have been determined using a combination of TI-205 nuclear magnetic resonance spectroscopy and competitio... |
2462311 | Glycocalyx electrostatic potential profile analysis: ion, pH, steric, and charge effects. | The Poisson-Boltzmann equation is modified to consider charge ionogenicity, steric exclusion, and charge distribution in order to describe the perimembranous electrostatic potential profile in a manner consistent with the known morphology and biochemical composition of the cell's glycocalyx. Exact numerical and approxi... |
3198352 | Comparative chemical structure and pharmacokinetics of MRI contrast agents. | The blood clearance kinetics of five gadolinium complexes, Gd(L), were determined in rats and the results interpreted in terms of an open two-compartment pharmacokinetic model. The complexes were tested in vitro for stability in serum and in aqueous solutions of ions that they might encounter in vivo and that might be ... |
3198351 | Gd-DOTA, a potential MRI contrast agent. Current status of physicochemical knowledge. | The complex (Gd-DOTA) meglumine has recently been used as an MRI contrast agent in humans. Due to its particularly interesting physicochemical properties, the risk of in vivo dissociation of the complex is reduced. Indeed, as a result of the macrocyclic nature of the DOTA ligand, Gd-DOTA appears very stable, demonstrat... |
2461701 | Purification and characterization of a novel thermostable beta-amylase from Clostridium thermosulphurogenes. | An extracellular beta-amylase from Clostridium thermosulphurogenes was purified 811-fold to homogeneity, and its general molecular, physico-chemical and catalytic properties were determined. The native enzyme was a tetramer of 210 kDa composed of a single type subunit; its 20 amino acid N-terminus displayed 45% homolog... |
3184189 | Conformational differences between alpha-cyclodextrin in aqueous solution and in crystalline form. A molecular dynamics study. | The computer simulation technique of molecular dynamics is a powerful tool to delineate the conformational differences between a molecule in different environments. As an illustration, the difference between an alpha-cyclodextrin molecule in aqueous solution and in crystalline form is determined. Two molecular dynamics... |
2903177 | Effects of transport temperature and medium on recovery of Bordetella pertussis from nasopharyngeal swabs. | We compared relative recoveries of Bordetella pertussis from simulated nasopharyngeal (NP) specimens incubated in three separate transport media at different temperatures. Transport media included one-half-strength Regan-Lowe (RL.5), Regan-Lowe with one-half-strength agar (RL.5A), and buffered charcoal-yeast extract ag... |
2460240 | Projection pathways, co-existence of peptides and synaptic organization of nerve fibers in the inferior mesenteric ganglion of the guinea-pig. | The presence of immunoreactive enkephalin, dynorphin, vasoactive intestinal polypeptide, cholecystokinin, substance P and neuropeptide Y in nerve fibers that project to the guinea-pig inferior mesenteric ganglion was analysed, after different denervation and ligation procedures. A quantitative analysis demonstrates tha... |
3052434 | Purification, crystallization and properties of porphobilinogen deaminase from a recombinant strain of Escherichia coli K12. | Porphobilinogen deaminase has been purified and crystallized from an overproducing recombinant strain of Escherichia coli harbouring a hemC-containing plasmid which has permitted the purification of milligram quantities of the enzyme. Determination of the Mr of the enzyme by SDS/polyacrylamide-gel electrophoresis (35,0... |
3421322 | Double-barreled K+-selective microelectrodes based on dibenzo-18-crown-6. | Liquid ion-exchanger microelectrodes based on Corning code 477317 K+ exchanger are known to be much more sensitive to quaternary ammonium ions than to K+. In the presence of such cations, the capability of measuring K+ activities with Corning microelectrodes may be seriously impaired. We have developed a neutral carrie... |
3418128 | Development of a serum-free medium for in vitro immune responses by using beta-cyclodextrin. Demonstration of the requirements for polyamines. | A serum-free medium has been developed which is able to support primary antibody responses by cultured murine lymphocytes. This medium is based on RPMI 1640 that is supplemented with beta-cyclodextrin, insulin, transferrin, albumin, low density lipoprotein, putrescine and L-alanine as substitutes for fetal calf serum. ... |
2843566 | Membrane protein lesions in erythrocytes with Heinz bodies. | We studied Heinz body-containing erythrocytes with three different unstable hemoglobins: Nottingham, Brockton, and unclassified. We demonstrated two classes of membrane protein defects in unstable hemoglobin-containing cells (UH-RBCs), a defect of the spectrin-depleted inside-out vesicle (UH-IOV), and a defect of spect... |
3047153 | Biogenesis of thylakoid membranes is controlled by light intensity in the conditional chlorophyll b-deficient CD3 mutant of wheat. | Biogenesis of thylakoid membranes in the conditional chlorophyll b-deficient CD3 mutant of wheat is dramatically altered by relatively small differences in the light intensity under which seedlings are grown. When the CD3 mutant is grown at 400 microE/m2 S (high light, about one-fifth full sunlight) plants are deficien... |
3417773 | Organization of the actin filament cytoskeleton in the intestinal brush border: a quantitative and qualitative immunoelectron microscope study. | In the present study we have used immunogold labeling of ultrathin sections of the intact chicken and human intestinal epithelium to obtain further insight into the molecular structure of the brush-border cytoskeleton. Actin, villin, and fimbrin were found within the entire microvillus filament bundle, from the tip to ... |
3417772 | Fluorescent microtubules break up under illumination. | We have synthesized three new fluorescent analogues of tubulin, using fluorescein or rhodamine groups attached to N-hydroxy-succinimidyl esters, and have partially characterized the properties of these analogues. We have also further characterized the tubulin derivatized with dichlorotriazinyl-aminofluorescein that has... |
2843503 | Microenvironment of two different extrinsic fluorescence probes in Na+,K+-ATPase changes out of phase during sequential appearance of reaction intermediates. | Na+,K+-ATPase from pig kidney was sequentially modified with N-[p-(2-benzimidazolyl)phenyl]maleimide (BIPM) at Cys-964 and fluorescein isothiocyanate (FITC) at Lys-501. The resulting preparation showed little Na+,K+-ATPase activity with retention of nearly 90% of phosphorylation capacity from acetyl phosphate. The addi... |
3416420 | Chromogenic ionophore-based methods for spectrophotometric assay of sodium and potassium in serum and plasma. | We report spectrophotometric methods for quantifying sodium and potassium in serum and plasma without sample pretreatment or solvent-extraction steps. The methods are based on novel chromogenic ionophores characterized by molecular structures highly preorganized for binding, which result in exceptionally high sensitivi... |
2901104 | Antibodies to synthetic peptides from the tubulin regulatory domain interact with tubulin and microtubules. | The carboxyl-terminal region of tubulin alpha and beta subunits plays a major role in regulating its assembly into microtubules and constitutes an essential domain for the selective interaction of microtubule-associated proteins (MAPs). With the goal of understanding the structural basis of the regulatory function of t... |
2842786 | Participation of Escherichia coli integration host factor in the P1 plasmid partition system. | Stable maintenance of the plasmid prophage of bacteriophage P1 requires the P1 ParB protein, which acts on a DNA site termed parS. Fractionation of extracts from Escherichia coli cells overproducing ParB revealed that a host factor, in addition to ParB, is required to observe maximal binding to parS, as detected by a n... |
2842781 | In vitro assay for protein-protein interaction: carboxyl-terminal 40 residues of simian virus 40 structural protein VP3 contain a determinant for interaction with VP1. | Intermolecular interactions between polypeptide chains play essential roles in the functioning of proteins. We describe here an in vitro assay system for identifying and characterizing such interactions. Such interactions are difficult to study in vivo. We have translated synthetic, nonmethyl-capped RNAs in a cell-free... |
3413096 | Detection of DNA looping due to simultaneous interaction of a DNA-binding protein with two spatially separated binding sites on DNA. | We describe different and relatively rapid biochemical techniques to detect protein-mediated DNA looping. These techniques, based on enhancement of DNA knotting and that of ligase-catalyzed cyclization, were used to show that the replication initiator protein of plasmid R6K can bring together two intramolecular gamma o... |
2970637 | Purification and partial characterization of a receptor protein for mouse interferon gamma. | A receptor protein for mouse interferon gamma has been purified from solubilized plasma membranes of the mouse monomyelocytic cell line WEHI-3. Sequential wheat germ agglutinin and ligand affinity chromatography of membranes extracted with octyl beta-D-glucopyranoside resulted in at least a 680-fold purification of the... |
3045087 | Structures of the promoter and operator of the glpD gene encoding aerobic sn-glycerol-3-phosphate dehydrogenase of Escherichia coli K-12. | The nucleotide sequence of a 690-base-pair DNA segment containing the control region for the glpD gene encoding aerobic sn-glycerol-3-phosphate dehydrogenase was determined. An ATG translation initiation codon with an adjacent ribosome-binding site was found which preceded an open reading frame continuing 61 codons to ... |
3137213 | Reexamination of the role of autolysis in the development of Myxococcus xanthus. | It has been widely reported that 80 to 90% of the cell population undergoes autolysis during sporulation in Myxococcus xanthus. A re-evaluation of the techniques used to measure autolysis in M. xanthus showed that the methods previously used to draw this conclusion are subject to artifacts, which result in a substantia... |
2841496 | TF1, the bacteriophage SPO1-encoded type II DNA-binding protein, is essential for viral multiplication. | The lytic Bacillus subtilis bacteriophage SPO1 encodes an abundant, 99-amino-acid type II DNA-binding protein, transcription factor 1 (TF1). TF1 is special in this family of procaryotic chromatin-forming proteins in its preference for hydroxymethyluracil-containing DNA, such as SPO1 DNA, and in binding with high affini... |
3404580 | Assembly-dependent maturation cleavage in provirions of a small icosahedral insect ribovirus. | Extracts from nodavirus-infected Drosophila cells contained detergent-labile 140S "young" particles much richer than mature virions in their content of protein alpha, a precursor of coat proteins beta and gamma. Incorporation studies in infected cells showed that most newly synthesized alpha protein was assembled into ... |
2841491 | Linker scan analysis of the early regulatory region of human papovavirus BK. | BK virus (BKV) is a human papovavirus which latently infects a majority of the world population. Reactivation of this virus is associated with acute hemorrhagic cystitis, and BKV DNA has been found in human tumor tissue. BKV is one of many highly homologous papovaviruses, including simian virus 40 and JC virus, which d... |
2841465 | Interaction between the octamer-binding protein nuclear factor III and the adenovirus origin of DNA replication. | Nuclear factor III (NFIII) is a HeLa sequence-specific DNA-binding protein that stimulates initiation of adenovirus DNA replication in vitro and may be involved in regulation of transcription of several cellular and viral genes. We have studied the interaction between NFIII and the binding site in the adenovirus type 2... |
3136206 | A reliable method combining horseradish peroxidase histochemistry with immuno-beta-galactosidase staining. | A sensitive combination of horseradish peroxidase (HRP) tracing and immunohistochemistry was used by Rye et al. [J Histochem Cytochem (1984) 32:1145] in a search for the origins of neurotransmitter- and neuromodulator-containing nerve fibers in brain. In this combination, peroxidase as a marker in immunohistochemistry ... |
18964608 | Metal complexes of 1-oxa-4,7,10-triazacyclododecane-N,N',N''-triacetic acid. | The macrocyclic complexone 1-oxa-4,7,10-triazacyclododecane-N,N',N''-triacetic acid (cODTA) has been synthesized and its protona constants, stability constants of metal complexes and enthalpy changes for the formation of alkaline-earth complexes have been determined. Although it is not so powerful a complexing agent as... |
17790041 | The structure and symmetry of crystalline solid solutions: a general revision. | Mixed single crystals composed of host and guest organic molecules of similar structures and shapes are shown to comprise sectors with different host-guest distributions and to have symmetries lower than that of the host crystal. These properties are determined by the structure of the guest and the surface structures o... |
16666284 | Phosphorylation and dephosphorylation reactions of the red beet plasma membrane ATPase studied in the transient state. | The reaction mechanism of the solubilized red beet (Beta vulgaris L.) plasma membrane ATPase was studied with a rapid quenching apparatus. Using a dual-labeled substrate ([gamma-(32)P]ATP and [5',8-(3)H]ATP), the presteady-state time course of phosphoenzyme formation, phosphate liberation and ADP liberation was examine... |
3271518 | On the occurrence of three-center hydrogen bonds in cyclodextrins in crystalline form and in aqueous solution: comparison of neutron diffraction and molecular dynamics results. | Three-center (bifurcated) hydrogen bonds may play a role by serving as an intermediate state between different dynamically changing hydrogen bonding patterns. Hydrogen bonding configurations can be studied experimentally by neutron diffraction and theoretically by computer simulation techniques. Here, both methods are ... |
2974924 | Step-arrest mutants of FLP recombinase: implications for the catalytic mechanism of DNA recombination. | The site-specific recombinase (FLP) encoded by the yeast plasmid 2 micron circle belongs to the integrase (of phage lambda) family of recombinases. The sparse homology within the members of this family contrasts with the invariance of three residues, His-396, Arg-399, and Tyr-433 (the numbers correspond to the family a... |
2848548 | Membrane D2 T antigen: characterization and comparison with its nuclear counterpart. | Up to 40% of membrane T antigen (D2 T antigen) produced by the adenovirus 2--simian virus 40 hybrid, Ad2+D2, remained tightly associated with membranes under alkaline conditions up to pH 11.5. The antigen could not be totally solubilized by treatment with ionic detergents, nonionic detergents, or both. These properties... |
3191914 | The 2.0 A X-ray crystal structure of chicken egg white cystatin and its possible mode of interaction with cysteine proteinases. | The crystal structure of chicken egg white cystatin has been solved by X-ray diffraction methods using the multiple isomorphous replacement technique. Its structure has been refined to a crystallographic R value of 0.19 using X-ray data between 6 and 2.0A. The molecule consists mainly of a straight five-turn alpha-heli... |
3056713 | Mutations in the nuclear lamin proteins resulting in their aberrant assembly in the cytoplasm. | We have constructed a series of mutations in the human A lamin cDNA to identify and alter the nuclear localization signal using an in vivo functional assay system. The nuclear localization signal in the lamin proteins has both structural and functional similarities with that of the SV40 large T-antigen. Mutations withi... |
2973347 | Roles of phosphorylation and nucleotide binding domains in calcium transport by sarcoplasmic reticulum adenosinetriphosphatase. | The roles of the phosphorylation (phosphorylated enzyme intermediate) and nucleotide binding domains in calcium transport were studied by comparing acetyl phosphate and ATP as substrates for the Ca2+-ATPase of sarcoplasmic reticulum vesicles. We found that the maximal level of phosphoenzyme obtained with either substra... |
3178736 | Albumin stimulates the release of lysophosphatidylcholine from cultured rat hepatocytes. | The effect of albumin on the release of [3H]lysophosphatidylcholine from cultured rat hepatocytes prelabelled with [Me-3H]choline was studied. In the absence of serum and albumin from the medium, the cells released essentially no [3H]lysophosphatidylcholine. Albumin stimulated this process dramatically, and it reached ... |
3140785 | Factors regulating the secretion of lysophosphatidylcholine by rat hepatocytes compared with the synthesis and secretion of phosphatidylcholine and triacylglycerol. Effects of albumin, cycloheximide, verapamil, EGTA and chlorpromazine. | 1. The synthesis and secretion of glycerolipid by monolayer cultures of rat hepatocytes was measured by determining the incorporations of [3H]glycerol, [3H]oleate and [14C]choline and by the absolute concentration of triacylglycerol. 2. The presence of albumin in the medium stimulated the accumulation of lysophosphatid... |
3173688 | Cytology and organization of rat cerebellar organ cultures. | Roller tube cultures of parasagittal cerebellar slices were taken from young rats aged 9-11 days, and maintained in vitro for 1-2 weeks. Morphological aspects of cell types and synaptic relationships in such organ cultures were examined at light and electron microscopic levels. Some neurons were marked by intracellular... |
2458750 | A new monoclonal antibody (A46-B/B10) highly specific for the blood group H type 2 epitope: generation, epitope analysis, serological and histological evaluation. | A monoclonal antibody recognizing the blood group H type 2 antigen has been obtained from a BALB/c mouse immunized with MCF-7 (human mammary carcinoma) cells. The specificity of this antibody (A46-B/B10, IgM, kappa) has been identified by haemagglutination tests, immunohistochemistry, binding inhibition studies, and ab... |
3413079 | Induction of macrophage antitumor activity by acetylated low density lipoprotein containing lipophilic muramyl tripeptide. | A method has been developed for the selective delivery of lipophilic immunomodulators to macrophages, which results in the induction of antitumor activity. This method utilizes exhaustively acetylated low density lipoprotein (acetyl-LDL) to deliver the lipophilic immunomodulator, muramyl tripeptide phosphatidylethanola... |
3411646 | Intra-abdominal abscess after penetrating abdominal trauma. | We reviewed our experience with intra-abdominal abscess after penetrating abdominal trauma. Of a total of 872 laparotomies (1980-1986), 29 patients (0.7% of stab wounds and 6% of gunshot wounds) developed abscesses. Pancreatic and duodenal injuries, in the presence of concomitant colon perforation, were most frequently... |
3043227 | The helical repeat of double-stranded DNA varies as a function of catenation and supercoiling. | DNA in the cell is intertwined at several levels: one polynucleotide strand wraps helically around its complement and the double helix is in turn coiled in space. The higher-order intertwining most often takes the form of supercoiling of the helix axis, but can also be observed as the wrapping of one DNA duplex around ... |
3400773 | Type IV collagen lateral associations in the EHS tumor matrix. Comparison with amniotic and in vitro networks. | The macromolecular structural organization of the type IV collagen network in the extracellular matrix of the EHS tumor has been investigated using a stereoscopic freeze-dry Pt/C replication technique. This network, which can be specifically decorated with type IV collagen antibody, is formed in great part by the later... |
2840661 | Evidence for the direct involvement of the rhinovirus canyon in receptor binding. | Evidence is presented that indicates a deep crevice located on the surface of human rhinovirus type 14 is involved in virion attachment to cellular receptors. By using mutagenesis of an infectious cDNA clone, 11 mutants were created by single amino acid substitutions or insertions at positions 103, 155, 220, 223, and 2... |
3399496 | Catalysis of a stereospecific bimolecular amide synthesis by an antibody. | We report a nonhydrolytic bimolecular aminolysis reaction catalyzed by an antibody. The stereospecific formation of an amide from racemic lactone plus an aromatic amine is described by a random equilibrium bireactant kinetic sequence. The observed turnover rate may be approximated from the measured difference between t... |
2899648 | Differentiation of phase I and variant strains of Bordetella pertussis on Congo red media. | The addition of Congo red, Trypan blue or haemin to the growth medium allowed the differentiation of phase-I and variant strains of Bordetella pertussis. Phase-I strains produced red (CR+), blue or dark brown colonies on a modified cyclodextrin solid medium containing Congo red, Trypan blue or haemin, respectively, whe... |
2839708 | Unique requirement for the PyF441 mutation for polyomavirus infection of F9 embryonal carcinoma cells. | A point mutation at nucleotide 5258 in the enhancer of the polyomavirus host range mutant F441 permits productive infection of F9 embryonal carcinoma cells, which, when undifferentiated, are refractory to infection by wild-type polyomavirus. Synthetic oligonucleotides were used to construct viral genomes containing all... |
2839702 | Kinetic, quantitative, and functional analysis of multiple forms of the vesicular stomatitis virus nucleocapsid protein in infected cells. | Multiple forms of the vesicular stomatitis virus nucleocapsid protein N have been detected in infected cells. One form is complexed with the viral NS protein in a 1:1 molar ratio, and the other forms are distinguished by their more rapid sedimentation rates on glycerol gradients. I performed a series of experiments des... |
2839687 | Antigenicity, function, and conformation of synthetic oligopeptides corresponding to amino-terminal sequences of wild-type and mutant matrix proteins of vesicular stomatitis virus. | The matrix (M) protein of vesicular stomatitis virus (VSV) has a major antigenic determinant (epitope 1) that maps to a region extending from amino acids 19 through 43 and transcription-inhibition activity that maps to the first 43 N-terminal amino acids (J.R. Ogden, R. Pal, and R. R. Wagner, J. Virol. 58:860-868, 1986... |
2455777 | Differences in the biophysical properties of the benzodiazepine/gamma-aminobutyric acid receptor chloride channel complex in the long-sleep and short-sleep mouse lines. | Significant differences in the thermal stability of benzodiazepine receptors were found in cerebral cortical membranes prepared from the long-sleep (LS) and short-sleep (SS) selected mouse lines. Thus, benzodiazepine receptors from LS mice were heat inactivated (55 degrees C) at a significantly faster rate than those f... |
2908539 | 500-MHz 1H-n.m.r. and conformational studies of fucosyloligosaccharides recognised by monoclonal antibodies with specificities related to Le(a), Le(b), and SSEA-1. | 500-MHz 1H-n.m.r. spectroscopy has been used to examine several fucosylated oligosaccharides in studies to characterise carbohydrate antigenic determinants recognised by monoclonal antibodies. Reduction of the oligosaccharides to give additional variants for analysis showed that oligosaccharides having an alpha-L-fucos... |
2854841 | Differential responsiveness of cerebellar Purkinje neurons to GABA and benzodiazepine receptor ligands in an animal model of hepatic encephalopathy. | The role of the GABA-benzodiazepine receptor complex in the pathogenesis of hepatic encephalopathy was investigated by recording the electrophysiological responses of single cerebellar Purkinje neurons from rabbits with hepatic encephalopathy due to galactosamine-induced fulminant hepatic failure. Both the GABAmimetic ... |
2975653 | Crystallization of and preliminary crystallographic data for Bacillus stearothermophilus cyclodextrin glucanotransferase. | Cyclodextrin glucanotransferase from Bacillus stearothermophilus TC-91 has been crystallized from an ammonium sulfate solution by the dialysis equilibrium method. The crystals belong to the orthorhombic system, space group P2(1)2(1)2(1), with cell dimensions of a = 125.5 A, b = 88.1 A, and c = 81.5 A. The crystals appe... |
3062906 | [Intra-arterial infusion treatment with prostaglandin E1 in patients with intermittent claudication]. | In a double-blind, placebo-controlled study 50 patients with peripheral arterial occlusive disease stage IIb were given daily or intra-arterial infusion of either 1 ampoule of Prostavasin (20 micrograms PGE 1) or 1 ampoule of placebo (646.7 micrograms alpha-cyclodextrin), each dissolved in 50 ml saline, over 60-120 min... |
3062132 | Synthetic and biosynthetic studies on vitamin B12. | Vitamin B12 is the anti-pernicious anemia vitamin. It functions as the main part of a coenzyme for a range of remarkable rearrangement reactions. The macrocycle for vitamin B12 is smaller by one carbon than that for chlorophyll and protoheme. Research is described involving numerous skills at the microscale level. In a... |
3058298 | Clinical laboratory applications of monoclonal antibodies. | Monoclonal antibody (MAb) technology is well recognized as a significant development for producing specific serologic reagents to a wide variety of antigens in unlimited amounts. These reagents have provided the means for developing a number of highly specific and reproducible immunological assays for rapid and accurat... |
3058297 | Laboratory, clinical, and epidemiological aspects of coagulase-negative staphylococci. | Coagulase-negative staphylococci, particularly Staphylococcus epidermidis, are increasingly important causes of nosocomial infection. Microbiologists and clinicians no longer can afford to disregard clinical isolates of coagulase-negative staphylococci as contaminants. Accurate species identification and antimicrobial ... |
2845542 | Decreased density distribution of mesenteric and diaphragmatic microvascular anionic charges during murine abdominal sepsis. | Pulmonary edema of sepsis is a consequence of increased transmural conductance for water and proteins at the level of lung microvessels induced by vasoactive endogenous mediators, liberated after activation of complement by bacterial endotoxins. Intermittent opening of interendothelial junctions at the level of post-ca... |
3262765 | Properties of a mutant Cre protein that alters the topological linkage of recombination products. | The bacteriophage P1 Cre-loxP site-specific recombination system consists of two components: the Cre recombinase protein and the loxP DNA sequence where recombination takes place. We report here on the analysis of a mutation in the cre structural gene that produces a mutant protein with altered recombination properties... |
2458990 | Characterization of purified hepatitis B surface antigen containing pre-S(2) epitopes expressed in Saccharomyces cerevisiae. | The cloning and expression of the hepatitis B middle-protein surface antigen gene in the yeast Saccharomyces cerevisiae is described. A generalized expression vector carrying the yeast glyceraldehyde-3-phosphate dehydrogenase gene promoter was used. Expressed material, in the form of supramolecular particles, was purif... |
3421941 | Cartilage proteoglycans. Assembly with hyaluronate and link protein as studied by electron microscopy. | Aggregates formed by the interaction of cartilage proteoglycan monomers and fragments thereof with hyaluronate were studied by electron microscopy by use of rotary shadowing [Wiedemann, Paulsson, Timpl, Engel & Heinegård (1984) Biochem. J. 224, 331-333]. The differences in shape and packing of the proteins bound along ... |
3138227 | Beta-cyclodextrin post-column fluorescence enhancement of aflatoxins for reverse-phase liquid chromatographic determination in corn. | beta-Cyclodextrin enhances the fluorescence of aflatoxins B1 and G1 in aqueous systems. This effect was utilized in developing a unique reverse-phase liquid chromatographic (LC) method for determination of aflatoxins B1, B2, G1, and G2 (B1 detection limit 1 ppb), without preparing derivatives of B1 and G1. The aflatoxi... |
2843361 | Cloning and characterization of a DNA gyrase B gene from Streptomyces sphaeroides that confers resistance to novobiocin. | A gyrB gene from Streptomyces sphaeroides, a producer of novobiocin, has been cloned in Streptomyces lividans, where it conferred resistance to novobiocin. The Streptomyces gyrB gene was sufficiently similar to a Bacillus subtilis gyrB probe to be specifically recognized during Southern analysis. Partial purification o... |
3046936 | A major 125-kd membrane glycoprotein of Saccharomyces cerevisiae is attached to the lipid bilayer through an inositol-containing phospholipid. | A number of plasma membrane glycoproteins of mammalian and protozoan origin are released from cells by phosphatidylinositol-specific phospholipase C. Some of these proteins have been shown to be attached to the lipid bilayer via a covalently linked, structurally complex glycophospholipid. Here we establish the existenc... |
2900845 | New, practical approach to detecting antibody to pertussis toxin for public health and clinical laboratories. | A new, practical method for determining antibody to pertussis toxin (PT) by enzyme-linked immunosorbent assay for public health and clinical laboratories is possible because of recent advances in understanding the pathobiology of Bordetella pertussis and the physicochemical properties of PT. The new approach does not r... |
3405221 | Ribonucleoproteins package 700 nucleotides of pre-mRNA into a repeating array of regular particles. | An assay for the in vitro assembly of HeLa cell 40S nuclear ribonucleoprotein particles (hnRNP particles) has been developed. The substrates were single-stranded nucleic acid polymers of defined length and sequence prepared in vitro and the six major core particle proteins from isolated 40S hnRNP. The fidelity of in vi... |
3043191 | Molecular cloning of the cDNA for a mutant mouse ribonucleotide reductase M1 that produces a dominant mutator phenotype in mammalian cells. | Mammalian ribonucleotide reductase is regulated by the binding of dATP and other nucleotide effectors to allosteric sites on subunit M1. Using mRNA from a mutant mouse T-lymphoma (S49) cell line, we have isolated a cDNA which encodes an altered, dATP feedback-resistant subunit M1. The mutant cDNA contains a single poin... |
3399409 | The helical repeat of underwound DNA in solution. | Closed circular DNA was relaxed with a topoisomerase in the presence of varying concentrations of the intercalating dye, ethidium bromide, to create underwound, planar DNA rings. We directly determined the helical repeat of these DNA molecules by the Gaussian center method and found that it varied as a simple predicted... |
3399408 | Bent DNA structures associated with several origins of replication are recognized by a unique enzyme from trypanosomatids. | Sequence-directed bending of the DNA double helix is a conformational variation found in both prokaryotic and eukaryotic organisms. The utilization of bent DNA structures from various sources as specific signals recognized by an enzyme is demonstrated here using a unique endonuclease purified from trypanosomatid cells.... |
3135536 | Detection of protein similarities using nucleotide sequence databases. | A simple procedure is described for finding similarities between proteins using nucleotide sequence databases. The approach is illustrated by several examples of previously unknown correspondences with important biological implications: Drosophila elongation factor Tu is shown to be encoded by two genes that are differ... |
3260935 | Human monoclonal IgG isotypes differ in complement activating function at the level of C4 as well as C1q. | Humanized antibodies are likely to have a major role in therapy and it is important to define their interaction with physiological effectors. By comparing a matched series of chimeric human mAbs we found that igG1 was most efficient in complement lysis, although IgG3 bound more C1q. To resolve this paradox we compared ... |
2456365 | Lipooligosaccharides (LOS) of Neisseria gonorrhoeae and Neisseria meningitidis have components that are immunochemically similar to precursors of human blood group antigens. Carbohydrate sequence specificity of the mouse monoclonal antibodies that recognize crossreacting antigens on LOS and human erythrocytes. | We have used mouse mAbs, 3F11 and 06B4, that are specific for highly conserved epitopes of Neisseria gonorrhoeae lipooligosaccharides (LOS) to identify immunochemically similar structures on human erythrocytes. mAb 3F11 agglutinated erythrocytes from all randomly selected adult humans, while mAb 06B4 agglutinated only ... |
3395126 | Actin assembly activity of cytochalasins and cytochalasin analogs assayed using fluorescence photobleaching recovery. | The effects on actin self-assembly of 9 common cytochalasins and 9 synthetic analogs have been assayed using fluorescence photobleaching recovery (FPR). The specific assembly activities of cytochalasins determined by this assay are (i) reduction of the fraction of actin molecules incorporated into filaments; (ii) incre... |
3393537 | Photophysical studies of tin(IV)-protoporphyrin: potential phototoxicity of a chemotherapeutic agent proposed for the prevention of neonatal jaundice. | The strongly light-absorbing metalloporphyrin tin(IV)-protoporphyrin IX (SnPP) is currently being considered as a chemotherapeutic agent for preventing severe hyperbilirubinemia in newborns, a condition usually treated by phototherapy with visible light. To assess the potential phototoxicity of SnPP we studied the phot... |
2455894 | Adhesion domain of human T11 (CD2) is encoded by a single exon. | The 50-kDa T11 (CD2) T-lymphocyte surface glycoprotein facilitates physical adhesion between T-lineage cells and their cognate cellular counterparts (cytotoxic T-lymphocytes-target cells, helper T lymphocytes-antigen-presenting cells, or thymocytes-thymic epithelium) as well as signaling through the antigen-specific T3... |
2839520 | Biochemical and functional responses stimulated by platelet-activating factor in murine peritoneal macrophages. | Platelet-activating factor (PAF) is a potent stimulant of leukocytes, including macrophages. To analyze the mechanisms of its effects upon macrophages, we determined whether macrophages bear specific surface receptors for PAF. By competitive radioactive binding assays, we determined two classes of specific receptors to... |
3392022 | Assembly of type I collagen fibrils de novo. Between 37 and 41 degrees C the process is limited by micro-unfolding of monomers. | The effects of temperature on the assembly of collagen fibrils were examined in a system in which collagen monomers are generated de novo and in a physiological buffer by specific enzymic cleavage of type I pC-collagen, an intermediate in the normal processing of type I procollagen to type I collagen. Increasing the te... |
2898784 | Identification of carbohydrate structures that are possible receptors for Neisseria gonorrhoeae. | Different strains and isogenic variants of Neisseria gonorrhoeae were assayed for their ability to bind glycolipids extracted from various sources. Among a large number of reference glycolipids, binding was observed only to lactosylceramide [Gal(beta 1-4)Glc(beta 1-1)Cer], isoglobotriaosylceramide [Gal(alpha 1-3)Gal(be... |
3384807 | Absence of a characteristic cell wall lipopolysaccharide in the phototrophic bacterium Chloroflexus aurantiacus. | Two strains of the gliding phototrophic bacterium Chloroflexus aurantiacus were investigated for the presence of lipopolysaccharide (LPS). With both strains, all fractions of hot phenol-water extracts and the extracted cell residues from whole cells or cell homogenates were found to be free from characteristic LPS cons... |
3384475 | Binding affinity of serum immunoglobulin G to cardiolipin and other phospholipids in patients with systemic lupus erythematosus and syphilis. | Qualitative and quantitative assays for human antibodies to cardiolipin and other phospholipids were used in tests for these reactions in sera from patients with systemic lupus erythematosus (SLE) and syphilis. Of 22 SLE serum samples tested by the qualitative assay, 8 showed positive staining to cardiolipin, phosphati... |
3290104 | Heparin-inhibitable basement membrane-binding protein of Streptococcus pyogenes. | Solubilized surface proteins of Streptococcus pyogenes serotype M6 were found by indirect immunofluorescence assays to bind selectively to proteoglycan-containing regions of basement membranes of kidney and cardiac muscle in vitro. Epithelial, endothelial, and interstitial cells were unstained. Binding of streptococcal... |
2836613 | Characterization of human rhinoviruses displaced by an anti-receptor monoclonal antibody. | The attachment of rhinoviruses to cellular receptors was studied by displacing bound virus particles with an anti-receptor monoclonal antibody. The two serotypes studied differed significantly with respect to the temperature dependence of displacement and the nature of the particles displaced. Binding was shown to be a... |
19431726 | Linear dichroism of chlorosomes from chloroflexus aurantiacus in compressed gels and electric fields. | The linear dichroism of chlorosomes from Chloroflexus aurantiacus was measured between 250 and 800 nm. To orient the chlorosomes we used a new way of compressing polyacrylamide gels, where the dimension of the gel along the measuring light-beam is kept constant. The press required for such a way of compressing is relat... |
17774576 | The discovery of crown ethers. | The discovery of the crown ethers stemmed from efforts to control the catalytic activity of vanadium and copper by complexation with multidentate ligands. The first crown ether, 2,3,11,12-dibenzo-1,4,7,10,13,16-hexaoxacyclo-octadeca-2,11-diene, was obtained in 0.4% yield during an attempt to prepare a phenolic ligand f... |
16347693 | Fluorescein Isothiocyanate-Labeled Lectin Analysis of the Surface of the Nitrogen-Fixing Bacterium Azospirillum brasilense by Flow Cytometry. | The cell surface of Azospirillum brasilense was probed by using fluorescein isothiocyanate (FITC)-labeled lectins, with binding determined by fluorescence-activated flow cytometry. Cells from nitrogen-fixing or ammonium-assimilating cultures reacted similarly to FITC-labeled lectins, with lectin binding in the followin... |
3273225 | Chemical probes reveal no evidence of Hoogsteen base pairing in complexes formed between echinomycin and DNA in solution. | Five different DNA fragments have been treated with a range of conformationally sensitive reagents in an effort to probe structural changes in DNA associated with binding of the bis-intercalating antibiotic echinomycin. For each probe, the intensity and pattern of its reactivity with DNA have been analyzed in order to ... |
3273224 | Zymogen activation: effect of peptides sequentially related to the bovine beta-trypsin N-terminus on Kazal inhibitor and benzamidine binding to bovine trypsinogen. | The activating effect of peptides sequentially related to the Ile 16-Val17-Gly18 N-terminus of bovine beta-trypsin (namely Ile-Val-Gly, Ile-Val, Ile-Leu, Ile-Ala, Val-Val, Leu-Val, and Val-Leu) on the thermodynamic parameters for the binding of the porcine pancreatic secretory trypsin inhibitor (Kazal inhibitor) and be... |
3273223 | Transition of environmental polarity of tyrosine-76 of Trimeresurus flavoviridis phospholipase A2 upon active site ligand binding. | Modification of Trimeresurus flavoviridis phospholipase A2 with a 5-fold molar excess of tetranitromethane produced 40% active mononitrotyrosyl phospholipase A2 in which Tyr-76 was specifically nitrated. This is in contrast to the case of mammalian pancreatic phospholipases A2 where Tyr-70 but not Tyr-76 was nitrated. ... |
3273222 | Conformational and receptor binding properties of human EGF and TGF-alpha second loop fragments. | The solution conformation of the second loop fragment of human EGF, [Ala20] EGF (14-31), was determined using two-dimensional NMR homonuclear Hartmann-Hahn and rotating frame nuclear Overhauser enhancement spectroscopy. The results are compared with the conformation of the second loop fragment of human TGF-alpha, [Ala2... |
2908504 | Glycolipid-directed FH6 monoclonal antibody recognizes high molecular weight glycoprotein antigen carrying sialyl Lex-i determinant in the culture supernatant of PC-9 cells. | The properties of the antigen recognized by monoclonal antibody FH6 have been analyzed. FH6 was originally generated against a glycolipid, i.e. a difucoganglioside isolated from human colonic adenocarcinoma, and specifically reacts with sialyl Lex-i determinant. Several culture supernatants of human carcinoma cell line... |
3273221 | Conformational homologies among cytokines: interleukins and colony stimulating factors. | Some 30 cytokine amino acid sequences (mainly interleukins, colony stimulating factors and tumor necrosis factors) have been examined for evidence of secondary structure as well as longer-range interactions of a type likely to lead to stable alpha-helical bundles. Most, though not all, of the cytokines examined have a ... |
3073165 | Hyaluronic acid-dependent change in the extracellular matrix of mouse dermal fibroblasts that is conducive to cell proliferation. | Fluorescein isothiocyanate (FITC)-labelled hyaluronic acid, when incubated with subconfluent cultures of mouse dermal fibroblasts, was incorporated into the extracellular matrix. Deposition of the fluorescent label reached the maximum about 48 h after its addition. Hyaluronic acid decasaccharide, but not octasaccharide... |
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