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2430984 | Mapping of domains in human laminin using monoclonal antibodies: localization of the neurite-promoting site. | Monoclonal antibodies were made against a truncated form of human laminin isolated from placenta. 12 antibodies were isolated and characterized. All antibodies stained basement membranes in placenta and immunoprecipitated laminin from media of cultured choriocarcinoma cells. Three antibodies, 3E5, 4C7, and 4E10, partia... |
3536962 | Titin and myosin, but not desmin, are linked during myofibrillogenesis in postmitotic mononucleated myoblasts. | Monoclonal antibodies specific for the muscle protein titin have been used in conjunction with muscle-specific antibodies against myofibrillar myosin heavy chains (MHCs) and desmin to study myogenesis in cultured cells. Desmin synthesis is initiated in replicating presumptive myoblasts, whereas the synthesis of titin a... |
3782291 | A fractionated cell-free system for analysis of prophase nuclear disassembly. | We describe a cell-free system in which a postribosomal supernatant (s140) from metaphase Chinese hamster ovary (CHO) cells induces prophase-like changes in isolated CHO cell nuclei, including chromatin condensation, and nuclear envelope and lamina disassembly. These events are strongly promoted by gamma-S-ATP and an A... |
3536925 | alpha-Carboxyl-linked glutamates in the folylpolyglutamates of Escherichia coli. | Folate cofactors in most cells contain polyglutamate side chains, which since the late 1940s have been assumed to be linked via their gamma-COOH groups. We report here an investigation of the structure of the polyglutamate chain attached to the folates of Escherichia coli. Folates were extracted from E. coli grown with... |
3023345 | A nicking enzyme from trypanosomatids which specifically affects the topological linking of duplex DNA circles. Purification and characterization. | Newly replicated duplex DNA minicircles of trypanosomal kinetoplast DNA are nicked in both their monomeric and catenated topological states, whereas mature ones are covalently sealed. The possibility that nicking may play a role during kinetoplast DNA replication by affecting the topological interconversions of monomer... |
2946666 | Mutations in an integration host factor-binding site: effect on lambda site-specific recombination and regulatory implications. | The manner in which integration host factor (IHF) regulates lambda site-specific recombination has been analyzed by examining the behavior of both wild-type and mutant DNAs in integrative and excisive recombination as well as in protein binding. While integrative recombination of an attP with two base changes in the H1... |
3535901 | Tunicamycin and papulacandin B inhibit incorporation of specific mannoproteins into the wall of Candida albicans regenerating protoplasts. | Regeneration of Candida albicans protoplasts began with the formation of a chitin network which was complemented after a lag of about 60 min by the deposition of beta-glucan. Proteins were incorporated early to the growing structure, beginning with the mannoproteins which are kept in place by non-covalent bonds. Incorp... |
12748711 | NTP Toxicology and Carcinogenesis Studies of Chlorinated Trisodium Phosphate (CAS No. 56802-99-4)* in B6C3F1 Mice (Gavage Studies). | Two-year toxicology and carcinogenesis studies of chlorinated trisodium phosphate, an inclusion complex of trisodium phosphate and sodium hypochlorite used in various cleaning compounds, were conducted by administering 0, 500, or 1,000 mg/kg (dose volume: 10 ml/kg) of the chemical in water by gavage, 5 days per week fo... |
3586389 | [Improved high performance liquid chromatography determination of hippuric acid and methylhippuric acid isomers in urine]. | A study was made on the effect of detection wavelength and separation mode of HPLC on determination of urinary hippuric acid (HA) and three isomers of methylhippuric acid (MHA). The interference of other constituents of urine in the determination was effectively decreased by detection at a short wavelength of 227.6 nm.... |
3548707 | Purification, N-terminal amino acid sequence and properties of hydroxymethylbilane synthase (porphobilinogen deaminase) from Escherichia coli. | Hydroxymethylbilane synthase (porphobilinogen deaminase) was purified to apparent homogeneity from Escherichia coli. The enzyme is a monomer of Mr approx. 40,000. The Km for porphobilinogen and relative Vmax. values have been obtained at various pH values over the range 6.2-8.8, enabling pK values for ionizable groups ... |
3824374 | Endotoxemia after abdominal surgery. | The blood level of endotoxin after operations in patients with digestive diseases, mainly liver cirrhosis and obstructive jaundice, and the complications most likely related to the presence of endotoxemia were investigated. Twenty-seven patients without either liver cirrhosis or obstructive jaundice showed a minimal el... |
3029560 | Current ideas on the significance of protein glycosylation. | Carbohydrate has been removed from a number of glycoproteins without major effect on the structure or enzyme activity of the protein. Thus carbohydrate has been suggested to underly a non-primary function for proteins, such as in relatively non-specific interactions with other carbohydrates or macromolecules, stabiliza... |
3029053 | Acceleration of the rate of fluorescence decrease by high concentrations of ATP under the condition of accumulation of ADP-sensitive phosphoenzyme in Na+,K+-ATPase. | Addition of up to 300 microM ATP in the presence of 2 M NaCl with MgCl2 to pig kidney Na+,K+-ATPase treated with N-[p-(2-benzimidazolyl)phenyl]maleimide seemed to be insufficient to saturate the rate of the fluorescence decrease. However, both the extent of the decrease and the amount of phosphoenzyme at a steady state... |
2434466 | Interaction of soybean beta-amylase with glucose. | The interaction of soybean beta-amylase with glucose was investigated by inhibition kinetics studies and spectroscopic measurements. The inhibition type, inhibitor constant (Ki) and dissociation constant (Kd) of beta-amylase-glucose complex were dependent on pH. At pH 8.0, glucose behaved as a competitive inhibitor (Ki... |
3803759 | Interaction of soman with beta-cyclodextrin. | Of the following neurotoxic agents, pinacolyl methylphosphonofluoridate (soman), isopropyl methylphosphonofluoridate (sarin) and ethyl N,N-dimethylphosphoramidocyanidate (tabun), only soman was inactivated appreciably at pH 7.40 by beta-cyclodextrin. The interaction of soman, a mixture of four stereoisomers designated ... |
3026455 | Molecular recognition between oligopeptides and nucleic acids: novel imidazole-containing oligopeptides related to netropsin that exhibit altered DNA sequence specificity. | Oligopeptides have been synthesized that are structurally related to the antiviral antitumor antibiotic netropsin, but in which each of the pyrrole units is successively replaced by an imidazole moiety, as well as their di- and triimidazole-containing counterparts. These compounds bind to duplex DNA with constants in t... |
3099830 | Topography of the high-affinity lysine binding site of plasminogen as defined with a specific antibody probe. | An antibody population that reacted with the high-affinity lysine binding site of human plasminogen was elicited by immunizing rabbits with an elastase degradation product containing kringles 1-3 (EDP I). This antibody was immunopurified by affinity chromatography on plasminogen-Sepharose and elution with 0.2 M 6-amino... |
3800341 | Novel mechanism for plasmid-mediated erythromycin resistance by pNE24 from Staphylococcus epidermidis. | We describe an unusual type of erythromycin resistance (Emr) mediated by a plasmid designated pNE24 from Staphylococcus epidermidis. This 26.5-kilobase plasmid encodes resistance strictly to 14-membered macrolide antibiotics, erythromycin, and oleandomycin. Resistance to other macrolide-lincosamide-streptogramin B (MLS... |
3798576 | [Study of the supramolecular organization of eukaryotic aminoacyl-tRNA-synthetases]. | The catalytical properties and thermostability of free leucyl-, glutamyl- and lysyl-tRNA synthetases and of the same synthetases in codosomes are compared. The stability of different aminoacyl-tRNA synthetases in highly purified preparations and in codosomes did not submit to any common regularities. Km for all substra... |
3025993 | Immunosuppression in viral infections. | Viruses may cause immunosuppression by a variety of mechanisms. This review delineates four categories. First, immunosuppression can result from the direct effects of viral replication on lymphocyte functions. Either all classes of lymphocytes can be affected, as occurs in measles, or the effect can be restricted to a ... |
3025610 | Two functional alpha-tubulin genes of the yeast Saccharomyces cerevisiae encode divergent proteins. | Two alpha-tubulin genes from the budding yeast Saccharomyces cerevisiae were identified and cloned by cross-species DNA homology. Nucleotide sequencing studies revealed that the two genes, named TUB1 and TUB3, encoded gene products of 447 and 445 amino acids, respectively, that are highly homologous to alpha-tubulins f... |
3790697 | Water structure in vitamin B12 coenzyme crystals. II. Structural characteristics of the solvent networks. | The geometrical details of the solvent structure in vitamin B12 coenzyme crystals with respect to hydrogen bonding and nonbonded contacts, are described. The individual H-bond geometries varied over wide ranges, similar to those observed in small molecule structures. Large deviations from tetrahedral coordination were ... |
3788975 | Chromatid repulsion associated with Roberts/SC phocomelia syndrome is reduced in malignant cells and not expressed in interspecies somatic-cell hybrids. | Different cell types from a female patient with Roberts/SC phocomelia syndrome were evaluated quantitatively for the presence of repulsion of heterochromatin and satellite regions of mitotic chromosomes. Whereas EBV-transformed lymphoblasts from an established cell line revealed these phenomena at frequencies equal to ... |
3786148 | Cationic porphyrins as probes of DNA structure. | The DNA binding specificity of a group of cationic manganese porphyrin complexes has been examined using DNase I footprinting methodology and by observing the sites of porphyrin-induced DNA strand scission in the presence of potassium superoxide. The compounds, which possess systematic changes in total charge, its dist... |
3536952 | Biosynthesis and supramolecular assembly of procollagen IV in neonatal lung. | The rate of biosynthesis of procollagen IV, the principal collagen of basement membranes, and the concentration of specific RNAs coding for procollagen IV were measured in neonatal rat lungs. Both decreased sharply at birth and then recovered again a few days later. The supramolecular assembly of procollagen IV was fol... |
2430974 | Inhibition of laminin self-assembly and interaction with type IV collagen by antibodies to the terminal domain of the long arm. | Laminin is a major glycoprotein of the basement membrane. Although its precise localization and orientation within this structure is unknown, it is presumably anchored to other macromolecules such as type IV collagen or proteoheparan sulfate. In vitro, laminin has the ability to self-assemble and to bind to type IV col... |
3490667 | Gene 32 protein, the single-stranded DNA binding protein from bacteriophage T4, is a zinc metalloprotein. | Gene 32 protein (g32P) isolated from bacteriophage T4-infected Escherichia coli and from an overproduction vector derived from the plasmid pKC30 contains 1 mol of tightly incorporated Zn(II) per mol of protein. A linear incorporation of three molar equivalents of p-hydroxymercuriphenylsulfonate (PMPS) results in a line... |
2877457 | Characterization of cDNA coding for human factor XIIIa. | A cDNA library prepared from human placenta has been screened for sequences coding for factor XIIIa, the enzymatically active subunit of the factor XIII complex that stabilizes blood clots through crosslinking of fibrin molecules. Two oligonucleotides, based on the amino acid sequences of tryptic peptides of factor XII... |
3022008 | Complex formation of simian virus 40 large T antigen with cellular protein p53. | We investigated the formation of native complexes between simian virus 40 large T antigen and the cellular protein p53 (T-p53) by using simian virus 40 tsA58-transformed mouse fibroblasts (tsA58 F2b). We observed that newly synthesized p53 bound to all structural subclasses of large T antigen detectable on sucrose dens... |
2429991 | Cachectin/tumor necrosis factor regulates hepatic acute-phase gene expression. | The monokine, cachectin/tumor necrosis factor (TNF) differs from interleukin 1 (IL-1) in primary structure and in recognition by a distinct cellular receptor. It does, however, encode effector functions that are similar to those of IL-1 and characteristic of the host response to inflammation or tissue injury. According... |
3533780 | Antibody-independent interactions of fibronectin, C1q, and human neutrophils with Treponema pallidum. | Although recent evidence suggests that fibronectin may be involved in the attachment of treponemes to mammalian cells, its possible role in promoting phagocytosis of Treponema pallidum has not been investigated. In the present study, we examined the antibody-independent interactions of fibronectin, C1q, and human polym... |
3770947 | Collagen binding to Staphylococcus aureus. | Staphylococcus aureus can bind soluble collagen in a specific, saturable manner. We have previously shown that some variability exists in the degree of collagen binding between different strains of heat-killed, formaldehyde-fixed S. aureus which are commercially available as immunologic reagents. The present study demo... |
2428646 | Disintegration of nucleoskeletal elements by metrizamide/2 M salt isopyknic centrifugation. | Supramolecular structures that remain bound to chromosomal DNA under high salt conditions are believed to anchor DNA in the interphase nuclear skeleton. In order to identify these anchorage structures, the non-DNA materials that remain firmly bound to chromosomal DNA under conditions that disintegrate the high salt-sta... |
3828493 | Characterization of a membrane-specific tubulin isoform by peptide mapping. | A membrane-specific tubulin-like protein, found in preparations of synaptic plasma membranes and brain mitochondria, was analyzed by chemical and proteolytic peptide mapping to determine which part of the molecule was different from cytoplasmic tubulin. The membrane polypeptide was identical to alpha tubulin in the fir... |
3813772 | Structural and chemical characterization of S-layers of selected strains of Bacillus stearothermophilus and Desulfotomaculum nigrificans. | The structures, amino acid- and neutral sugar compositions of the crystalline surface layers (S-layers) of four selected strains each of Bacillus stearothermophilus and Desulfotomaculum nigrificans were compared. Among the four strains of each species a remarkable diversity in the molecular weights of the S-layer subun... |
3802806 | Molecular recognition patterns of sesquiterpene lactones in costus-sensitive patients. | A molecular analysis of cross-reactions in costus-sensitive patients reveals that the most active sesquiterpene lactones are the ones with the lesser number of oxygenated substituents close to the alpha-methylene-gamma-butyrolactone ring. Cross-reactions with sesquiterpene lactones with different skeletons (germacranol... |
3791296 | Synthesis of branched cyclomalto-oligosaccharides using Pseudomonas isoamylase. | Branched cyclomalto-oligosaccharides (cyclodextrins) were synthesised from cyclomalto-oligosaccharides and maltose or maltotriose through the reverse action of Pseudomonas isoamylase. The reaction rate was greater with maltotriose than with maltose, and with increasing size of the cyclomalto-oligosaccharide (cG6 less t... |
3539183 | Permissible discontinuity region of the alpha-chain of hemoglobin: noncovalent interaction of heme and the complementary fragments alpha 1-30 and alpha 31-141. | Generation of a fragment-complementing system of the alpha-chain on limited proteolysis with Staphylococcus aureus V8 protease has been investigated. Digestion of the alpha-chain (0.4 mM) of hemoglobin with V8 protease in phosphate buffer at pH 6.0 and 37 degrees C is limited to the peptide bonds of Glu-23, Glu-27, Glu... |
3537941 | [Laminin: biosynthesis, structure and functions]. | Biosynthesized by epithelial, endodermal and Swann type cells, laminin (Lam) is a cross shaped multifunctional glycoprotein formed by the multimeric assembly of subunits which result from the activation of several genes. In vivo, depending on its location, because of its adhesive properties and multivalent affinities, ... |
3783794 | Pathways of transcytosis in the fenestrated endothelium of pancreatic capillaries. | A procedure which covalently attaches an electron dense tracer to cell surface sialoglycoconjugates was used in order to label the luminal surface of capillary endothelium in rat pancreas. Mild oxidation of the vasculature by perfusion with 1 mM sodium periodate, followed by a 30-90 min incubation with ferritin hydrazi... |
3536483 | The mom gene of bacteriophage Mu: the mechanism of methylation-dependent expression. | Transcription of the DNA modification gene (mom) of bacteriophage Mu requires methylation of three GATC sites upstream of the mom promoter by the Escherichia coli deoxyadenosine methylation function (Dam). The three sites map within a 40-bp segment termed region I. Small deletions, inversions, duplications and specific... |
3780673 | ATP-linked monomer-polymer equilibrium of smooth muscle myosin: the free folded monomer traps ADP.Pi. | In vitro and at physiological ionic strength, unphosphorylated smooth muscle myosin filaments dissolve on addition of ATP, forming folded (10S) myosin monomers. By following the fate of ATP and the time course of filament disassembly we have established details of the mechanism of this process. Myosin filaments first b... |
3780669 | The mouse glucocorticoid receptor: mapping of functional domains by cloning, sequencing and expression of wild-type and mutant receptor proteins. | We have isolated mouse glucocorticoid receptor (GR) cDNAs which, when expressed in transfected mammalian cells, produce a fully functional GR protein. Sequence analysis reveals an open reading frame of 2349 bp which could encode a protein of approximately 86,000 daltons. We have also isolated two receptor cDNAs from mo... |
3779694 | Efficient chemical synthesis of methyl beta-glycosides of beta-(1----6)-linked D-galacto-oligosaccharides by a stepwise and a blockwise approach. | Bromoacetylation of methyl 2,3,4-tri-O-benzoyl-beta-D-galactopyranoside (1) followed by cleavage of the methoxyl group from the resulting 6-O-bromoacetyl derivative 2 with 1,1-dichloromethyl methyl ether gave 2,3,4-tri-O-benzoyl-6-O-bromoacetyl-alpha-D-galactopyranosyl chloride (3). Reaction of 3 with 1, promoted by si... |
3022836 | Redox-linked proton translocation in cytochrome oxidase: the importance of gating electron flow. The effects of slip in a model transducer. | In at least one component of the mitochondrial respiratory chain, cytochrome c oxidase, exothermic electron transfer reactions are used to drive vectorial proton transport against an electrochemical hydrogen ion gradient across the mitochondrial inner membrane. The role of the gating of electrons (the regulation of the... |
3022834 | Resonance Raman spectral isolation of the a and a3 chromophores in cytochrome oxidase. | Resonance Raman spectra of reduced CO-bound cytochrome oxidase obtained at two different excitation frequencies (441.6 and 413.1 nm) are compared with the spectra of the fully reduced enzyme. In the spectra of the CO-bound complex only the cytochrome a modes are strongly enhanced with 441.6 nm excitation and only the m... |
3774008 | Phosphorylation of tubulin enhances its interaction with membranes. | Tubulin, the main component of intracellular microtubules, is also a major protein in subcellular membrane preparations and can interact with biological and artificial membranes in vitro. Of particular interest is the association of tubulin with postsynaptic junctional lattices enriched in a polypeptide of relative mol... |
2430000 | Epidermal effects of retinoids: supramolecular observations and clinical implications. | Retinoids, synthetic vitamin A analogs, stimulate mucous metaplasia and gap-junction proliferation in embryonic and neoplastic epidermis. Such effects demonstrate that vitamin A has potent effects on epidermal differentiation. Oddly, however, retinoid action in normal postnatal tissues, where these drugs are used clini... |
3771647 | Attachment of cells to basement membrane collagen type IV. | Of ten different cell lines examined, three showed distinct attachment and spreading on collagen IV substrates, and neither attachment nor spreading was enhanced by adding soluble laminin or fibronectin. This reaction was not inhibited by cycloheximide or antibodies to laminin, indicating a direct attachment to collage... |
3767370 | A comparative study of stearic and lignoceric acid oxidation by human skin fibroblasts. | Sensitive assays were developed for long chain and very long chain fatty acid oxidation in human skin fibroblast homogenates. Stearic and lignoceric acids were degraded by the fibroblasts by the beta-oxidation pathway. The cofactor requirements for stearic and lignoceric acid beta-oxidation were very similar but not id... |
2429318 | Association of La and Ro antigens with intracellular structures in HEp-2 carcinoma cells. | Monoclonal antibodies were raised against homogeneous Ro and La antigens, two proteins associated with Ro and La ribonucleoproteins (RNPs). The specificity of the monoclonal antibodies was proven by immunoblot analysis and by immunoprecipitation. The anti-Ro antibody reacted with a Mr 95,000 protein in a mouse lymphoma... |
3020537 | ATP-independent type II topoisomerase from trypanosomes. | We have characterized in Trypanosoma cruzi a DNA topoisomerase capable of decatenating complex trypanosomal kinetoplast DNA networks in the absence of ATP. The enzymatic activity requires Mg2+ and K+. Using a defined DNA topoisomer we showed that the linking number changes by steps of 2, which characterizes the enzyme ... |
3762708 | The nuclear lamina is a meshwork of intermediate-type filaments. | The nuclear lamina, a protein meshwork lining the nucleoplasmic surface of the inner nuclear membrane, is thought to provide a framework for organizing nuclear envelope structure and an anchoring site at the nuclear periphery for interphase chromatin. In several higher eukaryotic cells, the lamina appears to be a polym... |
3759989 | Cryogenic stabilization of myoglobin photoproducts. | The low frequency resonance Raman spectra of photodissociated carbon monoxymyoglobin at cryogenic temperatures (4-77 K) differ from those of deoxymyoglobin. Intensity differences occur in several low frequency porphyrin modes, and intensity and frequency differences occur in the iron-histidine stretching mode. This mod... |
3093463 | Control of developmental gene expression by cell-to-cell interactions in Myxococcus xanthus. | The ssbA mutants of Myxococcus xanthus behave as if they are unable to produce a cell-to-cell signal required for normal development. They are unable to form fruiting bodies or spores on developmental medium. They do sporulate, however, if allowed to develop in mixtures with wild-type cells. Fusions of developmentally ... |
3530336 | Some properties of the fatty alcohol oxidation system and reconstitution of microsomal oxidation activity in intestinal mucosa. | This paper describes the metabolism of fatty alcohols by microsomal and cytosolic fractions from intestinal mucosa. Microsomes of rabbit intestinal mucosa had a high activity of [1-14C]dodecanol oxidation as did those of liver. The intestinal cytosolic fraction also exhibited oxidation activity to a lesser extent than ... |
2427658 | Changes of neurotransmitter systems in chronic relapsing experimental allergic encephalomyelitis in rat brain and spinal cord. | Catecholamine and indoleamine neurotransmitters, together with some of their precursors and metabolites, were determined using HPLC in three brain and two spinal cord regions of Lewis rats with chronic relapsing allergic encephalomyelitis and of control rats injected with complete Freund's adjuvant. Three attacks and t... |
3453374 | Characterization of the ultrastructure and the self-assembly of the surface layer of Bacillus stearothermophilus strain NRS 2004/3a. | The ultrastructure of the crystalline surface layer (S-layer) of Bacillus stearothermophilus strain NRS 2004/3a has been characterized by electron microscopy supplemented by optical and computer image analysis. The S-layer, composed of glycoprotein subunits, has oblique symmetry, and can be extracted by guanidine hydro... |
17835564 | Characterization of compounds that induce symbiosis between sea anemone and anemone fish. | The species-specific partnership between the sea anemone and anemone fish in many parts of the Indo-Pacific region is a well-known phenomenon. Chemicals secreted by the sea anemone to elicit symbiotic behavior of the fish have been studied for two host-guest pairs, Radianthus kuekenthali (sea anemone)-Amphiprion peride... |
16453713 | Pigment-protein interactions in the photosynthetic reaction centre from Rhodopseudomonas viridis. | An X-ray structure analysis of the photosynthetic reaction centre from the purple bacterium Rhodopseudomonas viridis provides structural details of the pigment-binding sites. The photosynthetic pigments are found in rather hydrophobic environments provided by the subunits L and M. In addition to apolar interactions, th... |
16453712 | Assembly of cyanobacterial and higher plant ribulose bisphosphate carboxylase subunits into functional homologous and heterologous enzyme molecules in Escherichia coli. | The genes for the large (rbcL) and small (rbcS) subunits of ribulose-1,5 bisphosphate carboxylase-oxygenase (RuBPCase) from the cyanobacterium Synechococcus PCC 6301, and the rbcS gene of wheat, have been expressed in Escherichia coli in order to study homologous and heterologous enzyme assembly. Synechococcus L subuni... |
16347165 | Purification and Biochemical Analysis of the Cytoplasmic Membrane from the Desiccation-Tolerant Cyanobacterium Nostoc commune UTEX 584. | The cytoplasmic membrane of the heterocystous cyanobacterium Nostoc commune UTEX 584 was isolated free of thylakoids and phycobiliprotein-membrane complexes by flotation centrifugation. Purified membranes had a buoyant density of 1.07 g cm and were bright orange. Twelve major proteins were detected in the membrane, and... |
3795612 | Antinephritic effect of prostaglandin E1 on serum sickness nephritis in rats. (3). Suppression of leukocytes by prostaglandin E1 as a mechanism for preventing immune complex glomerulonephritis. | Serum sickness nephritis was produced in rats by repeated i.v. injections of rabbit serum albumin. After 12 weeks of antigen injection, the rats with proteinuria were subjected to a renal biopsy. Then half of the group was continuously given 300 micrograms/rat/day of PGE1 . alpha-cyclodextrin (PGE1 . CD) with mini osmo... |
3783664 | Inhomogeneity in epoxy resin standards for quantitative biological X-ray microanalysis. | It is shown by X-ray point analyses and line scans that the concentrations of sodium and potassium, as crown ether complexes, in epoxy resin may not be of uniform distribution. The concentrations may be substantially higher in a thin layer at the base of the block. It is recommended that chemical analysis of a selected... |
3096714 | Site-specific disruption of clathrin assembly produces novel structures. | Clathrin assembly in vitro produces a highly ordered polyhedral structure (basket). This resembles clathrin assembled in situ on coated pits and vesicles which form during receptor-mediated endocytosis. Sites on clathrin involved in assembly were identified by assembling clathrin in the presence of anti-clathrin monocl... |
3777909 | Antifungal macrodiolide from Streptomyces sp. | Aerobic fermentation cultures of Streptomyces sp. produced an antifungal macrodiolide. This new antibiotic consists of two units of homononactic acid linked to form a cyclic diester. An unknown polypeptide was also isolated in trace quantities. The antibiotic with polypeptide complex showed high levels of antifungal ac... |
3022619 | The benzodiazepine receptor. | The benzodiazepines are among the most widely used drugs in the world. When first introduced, little was known about their mechanism of action. However, in the last 20 years, our understanding of the chemistry and function of the central nervous system (CNS) has increased substantially. This knowledge has shed some lig... |
3020509 | Site-specific recombination and topoisomerization by Tn21 resolvase: role of metal ions. | The resolvase from the transposon Tn21 catalyses site-specific recombination between the two res sites on its DNA substrate both in the absence and presence of Mg2+ ions. This contrasts with reports on the resolvase from gamma-delta (Tn1000) and on other recombinational proteins that are homologous to Tn21 resolvase bu... |
3019556 | Self-assembly of purified polyomavirus capsid protein VP1. | The polyomavirus major capsid protein VP1, purified after expression of the recombinant gene in E. coli, was isolated as oligomers resembling the dissociated capsomeres derived from viral capsids. Image analysis of low-dose electron micrographs demonstrates that these VP1 oligomers are exclusively pentamers. The purifi... |
3756294 | A model for length-regulation in thick filaments of vertebrate skeletal myosin. | A mechanism for length regulation in the parallel-packed section of the thick filament is proposed. It is based on experiments done on synthetic, mini- and native filaments, and its primary purpose is to explain the physical basis of the kinetic mechanism for the assembly of synthetic thick filaments from myosin alone.... |
3462723 | Chemical reactivity at an antibody binding site elicited by mechanistic design of a synthetic antigen. | Monoaryl phosphonate esters, designated as analogs of the transition state in the hydrolysis of carboxylic esters, were synthesized and used as haptens to generate specific monoclonal antibodies. Some of these antibodies react with cognate aryl carboxylic esters to release a fluorescent alcohol. The reaction appears to... |
2944113 | Isolation and sequence of the cDNA for human protein S, a regulator of blood coagulation. | Protein S is a cofactor of activated protein C; together they function as a regulator of blood coagulation. A human liver cDNA library constructed in bacteriophage lambda gt11 was screened with DNA fragments from a full-length bovine cDNA clone encoding protein S. Several cDNA clones were isolated and sequenced. The co... |
3091898 | Human fibroblast chromatin states as effectors of the DNA-binding characteristics of benzo[a]pyrene anti-7,8-dihydrodiol 9,10-epoxide and two nonalkylating DNA-binding molecules. | Pure populations of mitotic or nonmitotic diploid human fibroblasts (greater than 98% pure) were exposed to [3H]benzo [a]pyrene (CAS: 50-32-8) anti-7,8-dihydrodiol 9,10-epoxide: r-7,t-8 dihydroxy-t-9, 10-oxy-7,8,9,10-tetrahydrobenzo [a]pyrene (or anti-diol-epoxide). In addition, metaphase chromosomes, interphase chroma... |
3745277 | The alteration of myosin isoform compartmentation in specific mutants of Caenorhabditis elegans. | Myosin isoforms A and B are located at the surface of the central and polar regions, respectively, of thick filaments in body muscle cells of Caenorhabditis elegans, whereas paramyosin and a distinct core structure comprise the backbones of these filaments. Thick filaments and related structures were isolated from nema... |
3528173 | Toxoplasma modifies macrophage phagosomes by secretion of a vesicular network rich in surface proteins. | Modification of macrophage phagosomes begins shortly after formation as Toxoplasma cells secrete membranous vesicles that form a reticulate network within the vacuole. The Toxoplasma-modified compartments then resist normal endocytic processing and digestion. We have used the pronounced Ca++-dependent stability of the ... |
2875062 | Helical structure of Bordetella pertussis fimbriae. | The helical structures of Bordetella pertussis fimbriae of serotypes 2 and 6 were determined by optical diffraction analysis of electron micrographs of negatively stained paracrystalline bundles of purified fimbriae. The fimbrial structure is based on an axial repeat of 13 nm that contains five repeating units in two c... |
3745121 | Ultrastructure of the cell surface cellulosome of Clostridium thermocellum and its interaction with cellulose. | The ultrastructural distribution of the cellulosome (a cellulose-binding, multicellulase-containing protein complex) on the cell surface of Clostridium thermocellum YS was examined by cytochemical techniques and immunoelectron microscopy. When cells of the bacterium were grown on cellobiose, cellulosome complexes were ... |
2943724 | Molecular recognition of siderophores in fungi: role of iron-surrounding N-acyl residues and the peptide backbone during membrane transport in Neurospora crassa. | Recognition of ferric siderophores in Neurospora crassa was found to depend on the number and kind of N-acyl residues that surrounded the iron coordination center. In the coprogen series, uptake decreased in the order of coprogen, neocoprogen I, and neocoprogen II, indicating that gradual replacement of the N-transanhy... |
3800937 | N-alkylation of exogenous haem analogues caused by drugs in isolated hepatocytes. Structural isomerism and chirality of the resulting porphyrins. | Isolated rat hepatocytes incubated with two suicide substrates of cytochrome P-450, 2-allyl-2-isopropylacetamide and 3,5-diethoxycarbonyl-4-ethyl-1,4-dihydro-2,6-dimethylpyridine(4-ethyl-DD C), convert exogenous mesohaem and deuterohaem into N-alkylated mesoporphyrins and deuteroporphyrins respectively. The N-alkylated... |
2432878 | Serum and liver cytosolic growth-hormone-binding proteins are antigenically identical with liver membrane 'receptor' types 1 and 2. | Studies with a panel of monoclonal antibodies (MAbs) reactive towards the presumptive rabbit liver growth-hormone (GH) receptor show that the rabbit serum GH-binding proteins share seven antigenic determinants (three at the hormone-binding site and four located elsewhere) with the liver cytosolic GH-binding proteins an... |
2945589 | Phosphorylation of the calcium adenosinetriphosphatase of sarcoplasmic reticulum: rate-limiting conformational change followed by rapid phosphoryl transfer. | The calcium adenosinetriphosphatase of sarcoplasmic reticulum, preincubated with Ca2+ on the vesicle exterior (cE X Ca2), reacts with 0.3-0.5 mM Mg X ATP to form covalent phosphoenzyme (E approximately P X Ca2) with an observed rate constant of 220 s-1 (pH 7.0, 25 degrees C, 100 mM KCl, 5 mM MgSO4, 23 microM free exter... |
3021018 | A quantitative decatenation assay for type II topoisomerases. | Type II topoisomerases catalyze decatenation of the catenated network of kinetoplast DNA [J. C. Marini, K. G. Miller, and P. T. Englund (1980) J. Biol. Chem. 255, 4976-4979]. The individual DNA circles and small catenanes produced during the decatenation reaction can be separated from the large network of substrate DNA... |
3763366 | Inclusion complexation of warfarin with cyclodextrins to improve some pharmaceutical characteristics. | Inclusion complexation of warfarin and alpha- or beta-cyclodextrins in water and in the solid phase were studied by a solubility method, a membrane permeation study, thin-layer chromatography, a dissolution study, IR spectroscopy and differential scanning calorimetry. The solubility of warfarin increased with the addit... |
3093629 | Enzymic clearing of lipaemic serum following total parenteral nutrition: determination of neonatal bilirubin as a model. | Bilirubin determinations in the newborn infant are one of the many analytical tests that can yield misleading results when the specimen is either iatrogenically or naturally lipaemic. Incorporation of a recently reported enzymic clarification system into a commercially available test kit enables one to conveniently and... |
3463507 | High affinity binding site for nuclear factor I next to the hepatitis B virus S gene promoter. | The hepatitis B virus (HBV) surface antigen (HBsAG) is encoded by the S gene under the regulation of a promoter in the pre-S1 region. The S gene promoter does not contain a 'TATA' box-like sequence, but there is a sequence resembling, in part, the late promoter of Simian virus 40 (SV40). In an attempt to study the regu... |
3530740 | A current genotoxicity database for heterocyclic thermic food mutagens. I. Genetically relevant endpoints. | Cooking, heat processing, or pyrolysis of protein-rich foods induce the formation of a series of structurally related heterocyclic aromatic bases that have been found to be mutagens. The primary genetic assay utilized to detect and isolate these mutagens has been the his reversion assay in Salmonella typhimurium. The c... |
3748821 | A left-handed (Z) conformation of poly(dA-dC).poly(dG-dT) induced by polyamines. | Blocks of potential Z-DNA forming alternating purine-pyrimidine (APP) sequences are widely dispersed in native DNAs. We have studied the effects of naturally occurring polyamines on the conformation of a synthetic APP sequence, poly(dA-dC).poly(dG-dT) by circular dichroism spectroscopy. In the presence of micromolar co... |
3091782 | Structural similarities and differences between neurofilament proteins from five different species as revealed using monoclonal antibodies. | Neurofilament (NF) proteins isolated from human, rabbit, rat, and chicken spinal cord white matter were immunoblotted with monoclonal antibodies (MAbs) raised to bovine NF immunogens. The aim of these experiments was to test the degree of epitope conservation among NF proteins from different vertebrate species. In so d... |
3743570 | 13C NMR evidence for bacteriochlorophyll c formation by the C5 pathway in green sulfur bacterium, Prosthecochloris. | The 13C NMR spectra of the pheophorbide of bacteriochlorophyll c, formed in the presence of L-[1-13C]glutamate and [2-13C]glycine and [13C]bicarbonate in Prosthecochloris aestaurii, were analysed. The isotope in the glutamate was specifically incorporated into the eight carbon atoms in the tetrapyrrole macrocycle deriv... |
2943591 | Interaction of enzymes involved in triosephosphate metabolism. Comparison of yeast and rabbit muscle cytoplasmic systems. | The affinity of baker's yeast (Saccharomyces cerevisiae) fructose-1,6-bisphosphate aldolase towards the metabolically related enzymes phosphofructokinase and glyceraldehyde-3-phosphate dehydrogenase was tested by using a fluorescence-probe technique with fluorescein isothiocyanate attached covalently to the enzymes. Th... |
3017466 | Single-headed binding of a spin-labeled-HMM-ADP complex to F-actin. Saturation transfer electron paramagnetic resonance and sedimentation studies. | The interaction of actin and spin-labeled heavy meromyosin (MSL-HMM) was studied in the presence and absence of adenosine diphosphate or 5'-adenyl-yl-imidodiphosphate (AMPPNP) to determine the contributions of single and double-headed binding. The extent of single-headed binding to actin was deduced from a comparison o... |
3091057 | Acute generalized microvascular injury by activated complement and hypoxia: the basis of the adult respiratory distress syndrome and multiple organ failure? | It has been suggested that generalized endothelial damage and permeability changes, induced by prolonged activation of the complement system and ensuing release of lysosomal enzymes, prostaglandins and toxic oxygen products, underlie the genesis of the Adult Respiratory Distress Syndrome (ARDS) and Multiple Organ Failu... |
3527066 | The role of magnesium and potassium ions in the molecular mechanism of ribosome assembly: hydrodynamic, conformational, and thermal stability studies of 16 S RNA from Escherichia coli ribosomes. | In an attempt to understand the role of magnesium ion in ribosome assembly in vitro, the hydrodynamic shape, conformation, and thermal stability of ribosomal 16 S RNA were studied systematically as a function of Mg2+ concentration by sedimentation velocity, intrinsic viscosity, circular dichroism, and difference ultrav... |
3090888 | Accumulation of arachidonate in triacylglycerols and unesterified fatty acids during ischemia and reflow in the isolated rat heart. Correlation with the loss of contractile function and the development of calcium overload. | Alterations in triacylglycerol and phospholipid metabolism are known to occur during the evolution of myocardial ischemic injury. The purpose of this study was to explore potential relationships between the accumulation of arachidonic acid and other fatty acids, the accumulation of triacylglycerol, and the progression ... |
3461474 | Analysis of sugar-binding sites in mammalian cell nuclei by quantitative flow microfluorometry. | Quantitative flow microfluorometry of neoglycoprotein (bovine serum albumin coupled to sugar and to fluorescein) binding demonstrated the existence of sugar-binding sites (i.e., lectin-like molecules) in isolated BHK cell nuclei. The very similar labeling intensities obtained with nuclei isolated by cell lysis and with... |
2426703 | Extracellular release of lymphocyte cytolytic pore-forming protein (perforin) after ionophore stimulation. | The cytolytic pore-forming protein (PFP, perforin) of lymphocyte granules has recently been isolated and characterized. The lytic activities expressed by both the isolated granules and the purified PFP require the presence of Ca2+. Here, we report on the extracellular release of PFP after stimulation of lymphocytes wit... |
3733878 | Regulation of microtubule composition and stability during nerve growth factor-promoted neurite outgrowth. | We have used the nerve growth factor (NGF)-responsive line of PC12 pheochromocytoma cells as a model system to study microtubule specializations associated with neurite outgrowth. PC12 cells treated with NGF cease proliferating and extend neurites. Long-term NGF treatment results in a two- to threefold increase in the ... |
3525575 | Type VI collagen in extracellular, 100-nm periodic filaments and fibrils: identification by immunoelectron microscopy. | Filaments and fibrils that exhibit a 100-nm axial periodicity and occur in the medium and in the deposited extracellular matrix of chicken embryo and human fibroblast cultures have been tentatively identified with type VI collagen on the basis of their similar structural characteristics (Bruns, R. R., 1984, J. Ultrastr... |
3525540 | The heme and Fe4S4 cluster in the crystallographic structure of Escherichia coli sulfite reductase. | Isolated hemoprotein subunits of Escherichia coli NADPH:sulfite reductase catalyze the 6-electron reduction of SO2-3 to S2-. The prosthetic groups of the hemoprotein, a siroheme and a Fe4S4 cluster, have been shown by spectroscopy to be tightly coupled. We have crystallized the isolated hemoprotein subunits and produce... |
3015883 | Cloning of multiple genes involved with cobalamin (Vitamin B12) biosynthesis in Bacillus megaterium. | An effective shotgun cloning procedure was developed for Bacillus megaterium by amplifying gene libraries in Bacillus subtilis. This technique was useful in isolating at least 11 genes from B. megaterium which are involved with cobalamin (vitamin B12) biosynthesis. Amplified plasmid banks were transformed into protopla... |
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