id stringlengths 4 8 | title stringlengths 1 642 | abstract stringlengths 50 17.9k |
|---|---|---|
2666165 | Remarks on the supramolecular organization of the glycolytic system in vivo. | The great latent catalytic capacity, manifested at the extremely high intracellular concentrations and in large apparent kcat/Km values, of the glycolytic enzymes on the one hand and their tendency in experiments in vitro to form functionally-specific flux-enhancing (channeling) complexes on the other, is considered an... |
2666164 | EGF-like domains in extracellular matrix proteins: localized signals for growth and differentiation? | Multidomain proteins of the extracellular matrix (ECM) play an important role in development and maintenance of cellular organization and in tissue repair. Several ECM proteins such as laminin, tenascin and thrombospondin contain domains with homology to epidermal growth factor (EGF) and exhibit growth promoting activi... |
2546671 | Gin-mediated recombination of catenated and knotted DNA substrates: implications for the mechanism of interaction between cis-acting sites. | The Gin DNA-inversion system of bacteriophage Mu normally requires a substrate containing two inverted recombination sites (gix) and an enhancer sequence on the same supercoiled DNA molecule. The reaction mechanism was investigated by separating these sites on catenated rings. Catenanes with the gix sites on one circle... |
2473781 | A new strategy for the study of oligomeric enzymes: gamma-glutamyltransferase in reversed micelles of surfactants in organic solvents. | A heterodimeric enzyme (gamma-glutamyltransferase) was studied in the reversed micellar medium of Aerosol OT (AOT) in octane. As was shown earlier, the size (radius) of inner cavity of the AOT-reversed micelles is determined by their hydration degree, i.e., [H2O]/[AOT] molar ratio, in the system. Owing to this, the dep... |
2748584 | Unusually stable helix formation in short alanine-based peptides. | Short, 16-residue, alanine-based peptides show stable alpha-helix formation in H2O. This result is surprising when contrasted with the classical view that regards the alpha-helix as a marginally stable structure in H2O and considers short helices unstable. The alanine-based peptides are solubilized by insertion of thre... |
2745546 | Functional sorting of actin isoforms in microvascular pericytes. | We characterized the form and distribution of muscle and nonmuscle actin within retinal pericytes. Antibodies with demonstrable specificities for the actin isoforms were used in localization and immunoprecipitation experiments to identify those cellular domains that were enriched or deficient in one or several actin is... |
2663878 | An antibody against secretogranin I (chromogranin B) is packaged into secretory granules. | We have investigated the sorting and packaging of secretory proteins into secretory granules by an immunological approach. An mAb against secretogranin I (chromogranin B), a secretory protein costored with various peptide hormones and neuropeptides in secretory granules of many endocrine cells and neurons, was expresse... |
2740331 | Characterization of a cDNA clone encoding human filaggrin and localization of the gene to chromosome region 1q21. | Filaggrins are an important class of intermediate filament-associated proteins that interact with keratin intermediate filaments of terminally differentiating mammalian epidermis. They show wide species variations and their aberrant expression has been implicated in a number of keratinizing disorders. We have isolated ... |
2472634 | Infectious potential of human immunodeficiency virus type 1 reverse transcriptase mutants with altered inhibitor sensitivity. | There is considerable interest in the potential of human immunodeficiency virus type 1 (HIV-1) to develop drug resistance, especially as 3'-azido-3'-deoxythymidine (Retrovir) is now in widespread clinical use to treat people with AIDS and AIDS-related complex (ARC). To address this possibility, mutations in the HIV rev... |
2500433 | Molecular recognition in the activation of human blood coagulation factor X. | Factor X can be activated by the extrinsic activation complex (factor VIIa:tissue factor), the intrinsic activation complex (factor IXa:factor VIIIa) and by an enzyme from Russell's viper venom (RVV-X). To identify the regions on the surface of factor X that mediate its association with these three activators, we have ... |
2500420 | Evidence for divalent cation (Ca2+)-stabilized oligomeric proteins and covalently bound protein-peptidoglycan complexes in the outer membrane of Rhizobium leguminosarum. | Two unusual characteristics of some outer membrane proteins of Rhizobium leguminosarum are described. First, most of the major outer membrane proteins could only be visualized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis after lysozyme treatment of the isolated cell envelopes, suggesting a very strong, ... |
2544556 | Segregation of relaxed replicated dimers when DNA ligase and DNA polymerase I are limited during oriC-specific DNA replication. | An in vitro Escherichia coli oriC-specific DNA replication system was used to investigate the DNA replication pathways of oriC plasmids. When this system was perturbed by the DNA ligase inhibitor nicotinamide mononucleotide (NMN), alterations occurred in the initiation of DNA synthesis and processing of intermediates a... |
2661527 | Accumulation of 3-(N-morpholino)propanesulfonate by osmotically stressed Escherichia coli K-12. | We found that exogenous morpholinopropanesulfonate (MOPS) is concentrated approximately fivefold in the free volume of the cytoplasm of Escherichia coli K-12 (strain MG1665) when grown at high osmolarity (1.1 OsM) in two different media containing 40 mM MOPS. MOPS was not accumulated by E. coli grown in low-osmolarity ... |
2661409 | Morphogenesis of abnormal elastic fibers in lungs of patients with panacinar and centriacinar emphysema. | Pulmonary elastic fibers in a patient with panacinar emphysema due to alpha-1-antitrypsin deficiency and three patients with centriacinar emphysema related to anthracosis were studied by electron microscopy and by light and electron microscopic immunohistochemistry for elastin. Four types of abnormal elastic fibers wer... |
2736923 | Use of extracorporeal supportive techniques as additional treatment for septic-induced multiple organ failure patients. | We compared retrospectively four similar groups of patients with multiple organ failure (MOF) due to sepsis. All of them were treated initially with conventional therapy, aprotinin as protease inhibitor and vitamin C with allopurinol as possible scavengers of oxygen-free radicals, were also added. After 24 h of no clin... |
2544227 | Association of Tat protein and viral mRNA with nuclear matrix from HIV-1-infected H9 cells. | The transactivating protein from human immunodeficiency virus type 1 (HIV-1), Tat, was found to bind to the nuclear matrix from uninfected and HIV-1-infected H9 cells. Addition of the Zn2+, Cd2+ and Cu2+ chelator o-phenanthroline destroyed the matrix fibrils and the binding affinity of Tat to the matrix. A sequential t... |
2731989 | Identification of functional antigenic segments of toxic shock syndrome toxin 1 by differential immunoreactivity and by differential mitogenic responses of human peripheral blood mononuclear cells, using active toxin fragments. | When toxic shock syndrome toxin 1 was subjected to papain hydrolysis, two serologically active fragments of 16.3 kilodaltons (16K fragment) and 12.4 kilodaltons (12K fragment) were generated, whereas a third fragment of 9.7 kilodaltons (10K fragment) was inactive. The biologic activities of the fragments were evaluated... |
2786091 | Activation of the human T-cell leukemia virus type I long terminal repeat by 12-O-tetradecanoylphorbol-13-acetate and by tax (p40x) occurs through similar but functionally distinct target sequences. | One potent transcriptional activator of human T-cell leukemia virus type I (HTLV-I) is virally encoded protein Tax (p40x). p40x trans-activates HTLV-I through the long terminal repeat (LTR) by using a triply repeated 21-base-pair sequence as the target. In this report we have characterized the induction of the HTLV-I L... |
9301925 | [Multiple organ failure following open heart surgery in adults]. | The cases multiple organ failure (MOF) which occurred post-operatively following open heart surgery in adults were studied on a pre and post-operative hemodynamics. Post-operative low cardiac output syndrome (LOS) was thought to result in decreased renal and hepatic perfusion with subsequent ischemic damage to these or... |
2484929 | Molecular conformation and ion transport of cyclic and linear ionophores. | X-ray crystal structure determinations and energy-minimization techniques provide conformational data on the complexed and uncomplexed forms of ion transport antibiotics of the shuttle and channel types. In the solid state, hexadecaisoleucinomycin (HEXIL), an analogue of valinomycin, is observed as an asymmetric macroc... |
2488267 | Electrostatic complementarity in molecular associations. | In this paper, I attempt to summarize the main qualitative features of electrostatic complementarity and similarity, important determinants of molecular recognition. The two aspects, Coulombic and hydrophobic matching, can be formulated in terms of molecular electrostatic potentials and fields. The Coulombic aspect is ... |
2488266 | Polyamine interaction with Z-DNA. | In order to elucidate the detailed Z-DNA interaction with polyamines and also to clarify the mutual molecular recognition between the left-handed helix and the biologically important polyamine molecule, several polyamine-Z-DNA hexamer complexes were crystallized and their crystal structures were determined by X-ray dif... |
2488265 | Applications of molecular graphics for the study of recognition. | Molecular recognition depends upon a precise structural complementarity between the pairs of molecules concerned. For example, the strong affinity between an antigen and its specific antibody can be negated by replacement of a single amino-acid residue. The protein beta-lactoglobulin from cows' milk is a member of a fa... |
2482332 | Nucleotide sequence of the neopullulanase gene from Bacillus stearothermophilus. | The gene (nplT) for a new type of pullulan-hydrolysing enzyme, neopullulanase, from Bacillus stearothermophilus TRS40 was sequenced. The DNA sequence revealed only one large open reading frame, composed of 1764 bases and 588 amino acid residues (Mr 69144). Although the thermostable neopullulanase contained eight cystei... |
2793968 | High-performance liquid chromatographic determination of ibuprofen, its metabolites and enantiomers in biological fluids. | An isocratic high-performance liquid chromatographic method to determine racemic ibuprofen (assay I) and its major metabolites (assay II) in biological fluids (plasma, urine, bile) using a conventional reversed-phase column is described. A third assay using beta-cyclodextrin as stationary phase (Cyclobond I) for the se... |
2779483 | Immunoelectron microscopical evidence that type V collagen is a fibrillar collagen: importance for an aggregating capability of the preparation for reconstituting banding fibrils. | Type V collagen has already been shown, in many immunohistochemical studies, to be widely distributed in connective tissues. Its supramolecular structure, however, has been unclear. We demonstrate that the major aggregates formed from type V collagen solution in vitro are fine fibrils with a D-periodic banding pattern.... |
2774181 | Determination of cyclodextrins and branched cyclodextrins by reversed-phase chromatography with pulsed amperometric detection and a membrane reactor. | A high-performance liquid chromatographic method has been developed for the determination of cyclodextrins (CDs) and branched CDs. The method involves their separation on a reversed-phase column using a mixture of water and acetonitrile as an eluant, eluant pH modification with a cation-exchange membrane reactor surrou... |
2769225 | Kinetics and stoichiometry of coupled Na efflux and Ca influx (Na/Ca exchange) in barnacle muscle cells. | Coupled Na+ exit/Ca2+ entry (Na/Ca exchange operating in the Ca2+ influx mode) was studied in giant barnacle muscle cells by measuring 22Na+ efflux and 45Ca2+ influx in internally perfused, ATP-fueled cells in which the Na+ pump was poisoned by 0.1 mM ouabain. Internal free Ca2+, [Ca2+]i, was controlled with a Ca-EGTA ... |
2549177 | Sodium-calcium exchange current. Dependence on internal Ca and Na and competitive binding of external Na and Ca. | Na-Ca exchange current was measured at various concentrations of internal Na [( Na]i) and Ca [( Ca]i) using intracellular perfusion technique and whole-cell voltage clamp in single cardiac ventricular cells of guinea pig. Internal Ca has an activating effect on Nai-Cao exchange beginning at approximately 10 nM and satu... |
2765645 | Mechanics and control of the cytoskeleton in Amoeba proteus. | Many models of the cytoskeletal motility of Amoeba proteus can be formulated in terms of the theory of reactive interpenetrating flow (Dembo and Harlow, 1986). We have devised numerical methodology for testing such models against the phenomenon of steady axisymmetric fountain flow. The simplest workable scheme revealed... |
2764572 | Partial purification and characterization of an NAD-dependent 3 beta-hydroxysteroid dehydrogenase from Clostridium innocuum. | In nine strains of Clostridium innocuum, 3 beta-hydroxysteroid-dehydrogenating activities were detected. 3 beta, 7 alpha, 12 alpha-Trihydroxy- and 3 beta-hydroxy-12-keto-5 beta-cholanoic acids were identified as reduction products of the respective 3-keto bile acids by gas-liquid chromatography and gas-liquid chromatog... |
2548439 | Cloning and characterization of a DNA gyrase A gene from Escherichia coli that confers clinical resistance to 4-quinolones. | Nalidixic acid, enoxacin, and other antibacterial 4-quinolones inhibit DNA gyrase activity by interrupting DNA breakage and reunion by A subunits of the A2B2 gyrase complex. Despite their clinical importance, the mode of quinolone action and mechanisms of resistance are poorly understood at the molecular level. Using a... |
2569343 | Prevention of physostigmine-, DFP-, and diazinon-induced acute toxicity by monoethylcholine and N-aminodeanol. | 1. Choline, and the choline analogues monoethylcholine (MEC) and N-aminodeanol (NAD) were examined for prophylactic activity in acute acetylcholinesterase inhibitor toxicity in mice. The rank order of potency of the compounds was MEC greater than NAD greater than choline. 2. Simultaneous administration of MEC (60 mg kg... |
2758220 | Negative inotropic activity of antilaminin IgG: participation of cholinergic mechanisms. | 1. Antilaminin IgG decreased the dF/dt of mouse isolated atria and inhibited the mechanical effect of acetylcholine in a non-competitive fashion. 2. Inhibitors of nicotinic and muscarinic cholinoceptors impaired the negative inotropic action of antilaminin IgG in mouse isolated atria. Hemicholinium and tetrodotoxin als... |
2666457 | White fibrous papulosis of the neck: a new clinicopathologic entity? | A clinical, histologic, and ultrastructural study of 32 cases of white fibrous papulosis of the neck was undertaken. Clinically, this condition is characterized by asymptomatic white papules that appear mainly around the neck in elderly persons. The papules are approximately 2 to 3 mm in diameter, round to oval, clearl... |
2546123 | Highly inducible expression from vectors containing multiple GRE's in CHO cells overexpressing the glucocorticoid receptor. | A conditional glucocorticoid-responsive expression vector system is described for highly inducible expression of heterologous genes in mammalian cells. This host-vector system requires high level expression of the glucocorticoid receptor (GR) protein in the host cell and multiple copies of the receptor binding site wit... |
2568183 | Morphology and immunocytochemistry of two endocrine cell types in the guinea-pig esophageal epithelium. | Two types of endocrine cells in the basal layer of the keratinized stratified squamous epithelium in the guinea-pig esophagus were studied with immunohistochemistry by means of a streptavidin-biotin-bridge technique and by the immunofluorescence double-labelling technique. Cell-type I exhibited immunoreactivity to chro... |
2525902 | Functions of the COOH-terminal region of cyclodextrin glucanotransferase of alkalophilic Bacillus sp. #1011: relation to catalyzing activity and pH stability. | Cyclodextrin glucanotransferase (beta-CGTase) of alkalophilic Bacillus sp. #1011 degrades starch to mainly beta-cyclodextrin (beta-CD). This enzyme is considered to contain an extra-polypeptide in its COOH-terminal region in addition to its NH2-terminal domain which exhibits the starch-degrading activity. To analyze th... |
2662917 | Seronegative rheumatoid arthritis, rheumatoid factor cross reactive idiotype expression, and hidden rheumatoid factors. | The major rheumatoid factor cross reactive idiotype (RCRI), defined by prototypic monoclonal rheumatoid factors (RFs), is expressed as a dominant idiotype by pokeweed mitogen induced plasma cells obtained from seropositive (RF+) patients with rheumatoid arthritis (RA). Some patients who meet clinical diagnostic criteri... |
2661564 | Inhibition of proteoglycan synthesis alters extracellular matrix deposition, proliferation, and cytoskeletal organization of rat aortic smooth muscle cells in culture. | Arterial proteoglycans have been implicated in several important physiological processes ranging from lipid metabolism to regulation of smooth muscle cell growth. Vascular smooth muscle (VSM) cells are the major producers of proteoglycans in the medial layer of blood vessels. To study functional consequences of alterat... |
2738089 | Primary structure analysis of an integral membrane glycoprotein of the nuclear pore. | The complete primary structure of an integral membrane glycoprotein of the nuclear pore was deduced from the cDNA sequence. The cDNA encodes a polypeptide of 204,205 D containing a 25-residue-long signal sequence, two hydrophobic segments that could function as transmembrane segments, and 13 potential N-linked oligosac... |
2661560 | Yeast nuclear envelope proteins cross react with an antibody against mammalian pore complex proteins. | We have used a monoclonal antibody raised against rat liver nuclear proteins to study two cross-reactive proteins in the yeast nucleus. In rat liver, this monoclonal antibody, mAb 414, binds to nuclear pore complex proteins, including one of molecular weight 62,000 (Davis, L. I., and G. Blobel. 1987. Proc. Natl. Acad. ... |
2734306 | Collagen fibrillogenesis in situ: fibril segments are intermediates in matrix assembly. | The assembly of discontinuous fibril segments and bundles was studied in 14-day chicken embryo tendons by using serial sections, transmission electron microscopy, and computer-assisted image reconstruction. Fibril segments were first found in extracytoplasmic channels, the sites of their polymerization; they also were ... |
2567514 | The PapG adhesin of uropathogenic Escherichia coli contains separate regions for receptor binding and for the incorporation into the pilus. | Most uropathogenic strains of Escherichia coli produce heteropolymeric organelles, known as P pili, that bind to the globoseries of glycolipids present in the urinary tract. The formation of a P pilus is the result of a family of related proteins being coordinately assembled into the structure in a defined order with t... |
2543969 | Correlation of paramagnetic states and molecular structure in bacterial photosynthetic reaction centers: the symmetry of the primary electron donor in Rhodopseudomonas viridis and Rhodobacter sphaeroides R-26. | The orientation of the principal axes of the primary electron donor triplet state measured in single crystals of photosynthetic reaction centers is compared to the x-ray structures of the bacteria Rhodobacter (Rb.) sphaeroides R-26 and Rhodopseudomonas (Rps.) viridis. The primary donor of Rps. viridis is significantly ... |
2471773 | Antibody recognition of the type 14 pneumococcal capsule. Evidence for a conformational epitope in a neutral polysaccharide. | Oligosaccharides consisting of one or more tetrasaccharide repeating units were derived from the capsular polysaccharide of type 14 pneumococcus (Pn14) by endo-beta-galactosidase digestion. The relative affinity of anticapsular antibody binding to derivative oligosaccharides of different chain lengths was measured in a... |
2498880 | Cloning of the major histocompatibility complex class II promoter binding protein affected in a hereditary defect in class II gene regulation. | The regulation of major histocompatibility complex class II gene expression is directly involved in the control of normal and abnormal immune responses. In humans, HLA-DR, -DQ, and -DP class II heterodimers are encoded by a family of alpha- and beta-chain genes clustered in the major histocompatibility complex. Their e... |
2657741 | Rapid turnover of microtubule-associated protein MAP2 in the axon revealed by microinjection of biotinylated MAP2 into cultured neurons. | We studied the mechanism of compartmentation of microtubule-associated protein 2 (MAP2) in the dendrites and cell bodies by using microinjection of biotin-labeled MAP2 into mature spinal cord neurons in culture. MAP2 molecules microinjected into the nerve cell body were distributed not only throughout the cytoplasm of ... |
2657734 | Translational repression in bacteriophage f1: characterization of the gene V protein target on the gene II mRNA. | Previous studies have shown that the single-stranded DNA binding protein of bacteriophage f1 (gene V protein) represses the translation of the mRNA of the phage-encoded replication protein (gene II protein). We have characterized phage mutations in the repressor and in its target. Using a gene II-lacZ translational fus... |
2726760 | Binding of actinomycin D to DNA: evidence for a nonclassical high-affinity binding mode that does not require GpC sites. | We have employed a combination of temperature-dependent UV absorption spectroscopy, circular dichroism, and batch calorimetry to characterize the binding of actinomycin D to a series of oligomeric DNA duplexes. We find the duplex [d(CGTCGACG)]2 to be unique in its ability to bind actinomycin D strongly despite the abse... |
2542590 | Overlapping octamer and TAATGARAT motifs in the VF65-response elements in herpes simplex virus immediate-early promoters represent independent binding sites for cellular nuclear factor III. | Expression of the immediate-early (IE) genes of herpes simplex virus (HSV) is specifically stimulated by a 65-kilodalton virion transcription factor (VF65 or VP16) that is introduced as a component of infecting virions. In both the IE175(ICP4) and IE110(ICP0) promoters, this activation requires an upstream cis-acting t... |
2542579 | Multiple EBNA1-binding sites are required to form an EBNA1-dependent enhancer and to activate a minimal replicative origin within oriP of Epstein-Barr virus. | EBNA1 activates the EBV plasmid maintenance sequence oriP by binding to its two essential regions. One region is a family of 30-base-pair (bp) repeats and is activated by EBNA1 to act as a transcriptional enhancer. The other region contains a 65-bp dyad symmetry and lacks enhancer function. To explore the functional di... |
2542571 | Induction of human interferon gene expression is associated with a nuclear factor that interacts with the NF-kappa B site of the human immunodeficiency virus enhancer. | The relationship between transcription of alpha and beta interferon (IFN-alpha and IFN-beta) genes and the interaction of IFN promoter-binding transcription factors has been examined in monoblastoid U937 cells following priming with recombinant IFN-alpha 2 (rIFN-alpha 2) and Sendai virus induction. Pretreatment of U937... |
2724409 | Identification of temperature-sensitive mutants of vaccinia virus that are defective in conversion of concatemeric replicative intermediates to the mature linear DNA genome. | Pulsed-field gel electrophoresis was used to screen temperature-sensitive mutants of vaccinia virus for the ability to convert replicated viral DNA into mature linear 185-kilobase hairpin-terminated genomes. Of 30 mutually noncomplementing mutants tested, 5 displayed a temperature-sensitive defect in the resolution of ... |
2724408 | Analysis of near-neighbor contacts in bacteriophage T4 wedges and hubless baseplates by using a cleavable chemical cross-linker. | Although bacteriophage T4 baseplate morphogenesis has been analyzed in some detail, there is little information available on the spatial arrangement and associations of its 150 subunits. We have therefore carried out the first analysis of its near-neighbor interactions by using the cleavable chemical cross-linker ethyl... |
2542221 | Developmental bypass suppression of Myxococcus xanthus csgA mutations. | The csgA mutations of Myxococcus xanthus (formerly known as spoC) inhibit sporulation as well as rippling, which involves ridges of cells moving in waves. Sporulating revertants of CsgA cells were isolated by direct selection, since spores are much more resistant to heat and ultrasonic treatment than are vegetative cel... |
2542163 | Cloning and expression of the streptococcal C5a peptidase gene in Escherichia coli: linkage to the type 12 M protein gene. | A genomic library of Streptococcus pyogenes CS24 DNA was constructed by cloning streptococcal DNA partially digested with Sau3A into the lambda replacement vector EMBL3. The expression of streptococcal C5a peptidase (SCP) was analyzed by radioimmunoassay with hyperimmune rabbit serum. Two clones, lambda 4.1 and lambda ... |
2721208 | Plasma tumor necrosis factor and mortality in critically ill septic patients. | Tumor necrosis factor (TNF) cachectin has been implicated as an important host mediator responsible for shock and multiple organ failure (MOF) observed during sepsis. Using a sensitive enzyme-linked immunosorbent assay, we measured plasma TNF levels in 43 septic patients suffering from a broad range of diseases. Measur... |
18964773 | Synthesis and characterization of some chromogenic crown ethers as potential optical sensors for potassium ions. | The complexing abilities of a series of chromogenic crown ethers for potassium and sodium ions have been investigated, by spectrophotometry for the reactions in solution, and by diffuse reflectance spectroscopy when the crown ethers were immobilized. The binding coefficients of the reagents increased with increasing ne... |
17757415 | Erratum. | In figure 3B (p. 699) of the report "Calicheamicin [unknown]1(I) and DNA: Molecular recognition process responsible for site-specificity" by N. Zein et al. (12 May, p. 697), the stereo pair was incorrectly printed and inverted. The correct representation is a mirror image of what was shown. |
16594051 | The chloroplast genome exists in multimeric forms. | Chloroplast DNA conformation was analyzed by pulse-field gel electrophoresis. We found that spinach leaf chloroplast DNA molecules exist in at least four distinct forms with the apparent molecular weights of monomer, dimer, trimer, and tetramer. Two-dimensional gel analysis of DNA after UV nicking and in the presence o... |
2763849 | [Application of beta-cyclodextrin during direct pressing of tablets]. | In case of tablets prepared by direct procedure the compressibility of beta-cyclodextrin has been studied. It has been established that beta-cyclodextrin--because of its very good flowing behaviour--can successfully be applied as ingredient in direct pressing. When hardness of tablets has to be increased 20% Avicel pH ... |
2667976 | Perturbations of the immune system by xenobiotics. | Classically, immunotoxicology has been defined as the study of adverse effect on the immune system associated with exposure to environmental chemicals, pharmacologic agents, and biologicals. Although a multitude of immune system defects may occur, these can be generally categorized as immunomodulation (immune suppressi... |
2758079 | [Phosphorylation of components of high molecular weight aminoacyl-tRNA-synthetase complex from the rabbit liver by associated casein kinase type I]. | The aminoacyl-tRNA synthetase complex from rabbit liver possesses an endogenous protein kinase activity. The associated protein kinase in the complex was defined as casein kinase I. Using FPLC, a fraction of the supramolecular complex with a high level of metabolic activity was isolated; this preparation was found to b... |
2758076 | [Principles of the organization and functioning of the metabolon microcompartment]. | The approaches to the elucidation of principles of metabolon functioning and the applicability of concepts of "protein-machine" and "conjugated ionic hydrogen bond systems" are discussed. The term "metabolon" refers to a supramolecular complex of sequential metabolic enzymes and structural elements of the cell. It has ... |
2755994 | Evaluation of sulfonated aluminum phthalocyanines for use in photochemotherapy. A study on the relative efficiencies of photoinactivation. | The cellular photosensitivity caused by aluminum phthalocyanines sulfonated to different degrees (AlPcSn) has been investigated. The phototoxic effect increased with decreasing number of sulfonate groups on the macrocycle, with the exception of AlPcS1 which was less phototoxic than AlPcS2 but more phototoxic than AlPcS... |
2746481 | Heptakis(2,6-di-O-methyl)-beta-cyclodextrin complexation with the antitumor agent chlorambucil. | The effects of heptakis(2,6-di-O-methyl)-beta-cyclodextrin (DIMEB) and of beta-cyclodextrin (beta-CD) on the aqueous solubility and stability of chlorambucil (CHL) have been compared. In the presence of 1.3 x 10(-3) M DIMEB, there is a greater than 20-fold increase in the stability of chlorambucil at 37 degrees C, pH 4... |
2663919 | Fc receptors on the surface of Toxoplasma gondii trophozoites: a confounding factor in testing for anti-Toxoplasma antibodies by indirect immunofluorescence. | Negative sera often produce false-positive polar patterns of fluorescence in indirect immunofluorescence tests for serum anti-Toxoplasma gondii antibodies, representing a confounding factor in the diagnosis of toxoplasmosis. In this work, we studied whether T. gondii trophozoites, the antigenic material used in the imm... |
2738138 | Host-guest complexation in capillary isotachophoresis. II. Determination of aminophenol and diaminobenzene isomers in permanent hair colorants by using capillary isotachophoresis. | The separation of 2-, 3- and 4-aminophenol and 1,2-, 1,3- and 1,4-diaminobenzene is studied by using capillary isotachophoresis. In order to obtain complete resolution of the six cations beta-cyclodextrin was used. The analytical method was used for the determination of aminophenol and diaminobenzene isomers in permane... |
2660102 | Direct evidence for the presence of left-handed conformation in a supramolecular assembly of polynucleotides. | Hexammine cobalt(III) chloride (Co(NH3)6(3+) provokes a B-DNA----Z-DNA----psi-DNA conformational transition in poly(dG-dC).poly(dG-dC) and poly(dG-m5dC).poly(dG-m5dC). The circular dichroism spectrum of psi-DNA is characterized by a manyfold increase of positive ellipticity in the range of 300-225 nm and the complete a... |
2731734 | A family of activator genes regulates expression of Rhizobium meliloti nodulation genes. | Nodulation (nod) gene expression in Rhizobium meliloti requires plant inducers and the activating protein product of the nodD gene. We have examined three genes in R. meliloti which have nodD activity and sequence homology. These three nodD genes are designated nodD1, nodD2 and nodD3, and have distinctive properties. T... |
2471518 | Valinomycin binds stoichiometrically to cytochrome c oxidase and changes its structure and function. | Valinomycin binds to soluble and reconstituted cytochrome c oxidase (COX) in a stoichiometric manner, as shown by a spectral shift of the oxidized gamma-band. No spectral change is found with nigericin or 18-crown-6 and in the absence of potassium ions. Titration of the proton pumping activity of reconstituted COX with... |
2471511 | Conformation-dependent recognition of a protein by T cells requires presentation without processing. | Presentation of a protein antigen to T cells is believed to follow its intracellular breakdown by the antigen-presenting cell, with the fragments constituting the trigger of immune recognition. It should then be expected that T-cell recognition of protein antigens in vitro will be independent of protein conformation. T... |
2730581 | Effect of ATP depletion and temperature on the transferrin-mediated uptake and release of iron by BeWo choriocarcinoma cells. | We have recently described the transferrin-mediated uptake and release of iron by BeWo cells [van der Ende, du Maine, Simmons, Schwartz & Strous (1987) J. Biol. Chem. 262, 8910-8916]. We now extend our studies of the mechanisms responsible for uptake and release of iron by these cells. Following preloading, 59Fe releas... |
2658057 | Molecular recognition and metal ion template synthesis. | Methods for the design and synthesis of ligands intended to be specific for a metal ion have been a recent chemical development. This article describes how this process can be inverted so that the specifics of the coordination environment around the metal ion can be used as a template in large-scale ligand synthesis. T... |
2542946 | Phenotypes of rotavirus reassortants depend upon the recipient genetic background. | We have previously characterized the biological and immunological properties of a simian rotavirus SA11 variant (4F) with an altered genome segment 4. The SA11-4F variant formed large plaques in the presence of protease, formed small clear plaques in the absence of protease, and grew to high titer in the presence of pr... |
2726746 | A glycosylation mutation affects cell fate in chimeras of Dictyostelium discoideum. | Prestalk and prespore cells form a simple pattern in the pseudoplasmodium of the cellular slime mold Dictyostelium discoideum. Prestalk cells are distinguished from prespore cells by a low level of expression of a glycoantigen on their surfaces and by reduced intercellular cohesion. We examined the possible significanc... |
2542759 | Ultraviolet irradiation selectively disrupts the gamma-aminobutyric acid/benzodiazepine receptor-linked chloride ionophore. | The ability of UV light to affect radioligand binding and 36Cl-uptake at the gamma-aminobutyric acidA (GABAA) receptor-chloride channel complex was examined. Exposure to 302 nm UV light produced a rapid (t1/2 = 4 min) reduction in [35S]t-butylbicyclo-phosphorothionate binding (assayed in the presence of 200 mM chloride... |
2723751 | Characterization of a partial cDNA clone for the NILE glycoprotein and identification of the encoded polypeptide domain. | A partial cDNA clone [2.4 kilobase (kb)] for the nerve growth factor-inducible large external (NILE) glycoprotein was selected from a lambda gt11 expression library constructed using mRNA from PC 12 cells. A 0.2 kb subclone (pNILE-1B) was used for Northern blot analysis of NILE message present in 2 NILE-positive neuron... |
2717946 | Calicheamicin gamma 1I and DNA: molecular recognition process responsible for site-specificity. | Calicheamicin gamma 1I is a recently discovered diyne-ene-containing antitumor antibiotic that cleaves DNA in a double-stranded fashion, a rarity among drugs, at specific sequences. It is proposed that the cutting specificity is due to a combination of the complementarity of the diyne-ene portion of the aglycone with D... |
2715178 | Location of the head-tail junction of myosin. | The tails of double-headed myosin molecules consist of an alpha-helical/coiled-coil structure composed of two identical polypeptides with a heptad repeat of hydrophobic amino acids that starts immediately after a conserved proline near position 847. Both muscle and nonmuscle myosins have this heptad repeat and it has b... |
2715177 | Arrangement of filaments and cross-links in the bee flight muscle Z disk by image analysis of oblique sections. | Information from oblique thin sections and from three-dimensional reconstructions of tilted, transverse thin sections (Cheng, N., and J. F. Deatherage. 1989. J. Cell Biol. 108:1761-1774) has been combined to determine the three-dimensional structure of the honeybee flight muscle Z disk at 70-A resolution. The overall s... |
2715176 | Three-dimensional reconstruction of the Z disk of sectioned bee flight muscle. | The three-dimensional structure of the central region of the Z disk of honeybee flight muscle has been determined to a resolution of 70 A by three-dimensional reconstruction from electron micrographs of tilted thin sections. The reconstructions show a complex assembly in which actin filaments terminate and are cross-li... |
2713405 | Spectroscopic analysis of chlorophyll model complexes: methyl ester ClFe(III)pheophorbides. | As models for chlorophyll a (Chl a), methyl ester ClFe(III)pheophorbides (1, pheophorbide a; 2, mesopheophorbide a; and 3, mesopyropheophorbide a) were examined by Fourier transform infrared (FTIR) absorption and resonance Raman (RR) spectroscopy. The infrared (IR) chlorin band above 1600 cm-1, assigned as a Ca-Cm mode... |
2709373 | Electrophilic derivatives of purines as irreversible inhibitors of A1 adenosine receptors. | Functionalized congeners derived from 1,3-dipropyl-8-phenylxanthine and from N6-phenyladenosine were derivatized to contain electrophilic groups (isothiocyanate, N-hydroxysuccinimide ester, maleimide, sulfonyl chloride, or alpha-haloacyl group) capable of reaction with nucleophiles on biopolymers. The goal was to inhib... |
2540220 | Recombinant interferon-gamma primes alveolar macrophages cultured in vitro for the release of leukotriene B4 in response to IgG stimulation. | The capacity of interferon-gamma to regulate the generation and release of leukotriene B4 (LTB4) from human alveolar macrophages of normal nonsmoking individuals was evaluated. When alveolar macrophages were incubated for 60 min with heat aggregated IgG (HAIgG), they generated and released 5.7 +/- 1.7 ng of LT B4 per 1... |
2540199 | Incorporation of exogenous circular DNA into large catenated networks in isolated nuclei. Evidence for involvement of the nuclear scaffold. | Circular plasmid DNA was efficiently converted into huge catenated intranuclear networks by incubation with isolated nuclei in the presence of ATP. The network production is abolished by omission of ATP, strongly inhibited by etoposide (VP-16), but only slightly inhibited by antibody to topoisomerase I, indicating that... |
2523381 | Analysis of ferrichrome biosynthesis in the phytopathogenic fungus Ustilago maydis: cloning of an ornithine-N5-oxygenase gene. | By using a non-enterobactin-producing enb-7 mutant of Salmonella typhimurium LT2 as a biological indicator, a novel screening method was developed for identifying mutants of Ustilago maydis defective in the biosynthesis of the siderophores ferrichrome and ferrichrome A. Two classes of siderophore mutations, both recess... |
2540156 | Genes required for developmental signalling in Myxococcus xanthus: three asg loci. | asg-carrying strains of Myxococcus xanthus arose in a selection for mutants defective in cell-cell signalling during fruiting body development. All 15 asg mutations examined were found to lie in one of three genetic loci, asgA, asgB, or asgC. The loci were defined by linkage to different insertions of transposon Tn5 an... |
2496034 | Immunodominant antigen of Actinobacillus actinomycetemcomitans Y4 in high-responder patients. | This study was undertaken to look for characteristics of the immunodominant antigen(s) of Actinobacillus actinomycetemcomitans Y4 that might help explain the high antibody titers in periodontitis patients. Radioimmunoassays (RIA) were performed on sera from 481 patients; sera from the 32 patients with the highest anti-... |
2707851 | Expression of pertussis toxin in Bordetella bronchiseptica and Bordetella parapertussis carrying recombinant plasmids. | Pertussis toxin is produced only by strains of Bordetella pertussis. Cloned genes encoding pertussis toxin from B. pertussis were transferred into Bordetella bronchiseptica and Bordetella parapertussis by conjugation. These transconjugants expressed pertussis toxin at levels comparable to those expressed by B. pertussi... |
2649693 | Unmyristylated Moloney murine leukemia virus Pr65gag is excluded from virus assembly and maturation events. | The gag precursor polyprotein of Moloney murine leukemia virus (MuLV) is normally modified by myristylation of the N-terminal glycine. Previous work showed that the Pr65gag lacking the myristylation site does not associate with cellular membranes or assemble into virus particles. We now report that it also is not cleav... |
16453883 | Positive and negative control of nod gene expression in Rhizobium meliloti is required for optimal nodulation. | We show that expression of common nodulation genes in Rhizobium meliloti is under positive as well as negative control. A repressor protein was found to be involved in the negative control of nod gene expression. Whereas the activator NodD protein binds to the conserved cis-regulatory element (nod-box) required for coo... |
2700434 | [Reinterpretation of the hepatic abscess, a new dimension in abdominal digestive surgery]. | Pyogenic abscess of the liver is viewed here as a surgical disease, which appears to raise doubts as to its actual identity. Though located in a given abdominal organ, such abscesses find it hard to recognize this as their exclusive setting and attempt to shrug off these traditional confines. They aspire, rightly or wr... |
2483675 | Differences between sites of binding to DNA and strand cleavage for complexes of bleomycin with iron or cobalt. | The sequence specificity of bleomycin A5 and of its light-activated cobalt complex were compared by examining the relative cleavage of each strand of two DNA fragments by either species. Significant differences between the two metallobleomycins were observed. The iron-bleomycin (Fe-BLM) complex cleaved the DNA molecule... |
2631865 | Production of anti-idiotypic antibodies by immunization with a pair of complementary peptides. | Previous investigations have suggested that pairs of peptides specified by complementary RNA sequences (termed complementary peptides) can interact with one another. In the light of this finding, we hypothesized that an antibody directed against a peptide might interact with an antibody against its complementary peptid... |
2561072 | A subsequence-specific DNA-binding domain resides in the 13 kDa amino terminus of the bacteriophage Mu transposase protein. | We have previously reported that the 13 kDa amino terminus of the 70 kDa bacteriophage D108 transposase protein (A gene product) contains a two-component, sequence-specific DNA-binding domain which specifically binds to the related bacteriophage Mu's right end (attR) in vitro. To extend these studies, we examined the a... |
2631864 | Hidden self-association of proteins. | Sedimentation equilibrium measurements were carried out on solutions of bovine serum albumin, aldolase, and ovalbumin in phosphate-buffered saline, pH 7.2, at 10 degrees C. The data obtained for each protein were analyzed to yield the dependence of apparent weight-average molecular weight upon protein concentration, ov... |
2631863 | Sequence simplification and the intra- and intermolecular self-recognition properties of vasopressin/neurophysin biosynthetic precursor. | The self-assembly properties of the arginine 8-vasopressin/bovine neurophysin II (AVP/BNPII) biosynthetic precursor were studied using glycopeptide-deleted and sequence-redesigned semisynthetic derivatives. Semisynthetic precursors were prepared by chemically coupling synthetic vasopressinyl sequence domains and native... |
2631862 | Fluorescence spectroscopic studies on tryptophan at the saccharide-binding site of castor bean hemagglutinin. | The environment of tryptophan in castor bean hemagglutinin (CBH) was analyzed by fluorescence spectroscopy with regard to saccharide binding. Upon binding of specific saccharides, the fluorescence maximum of 333 nm of CBH shifted to a wavelength 2 nm shorter, owing to the change in the environment of tryptophan at the ... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.