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2797192 | Transactivation of the Xenopus rRNA gene promoter by its enhancer. | A key question concerning the mechanism of transcriptional activation by enhancers is about the role of the DNA that connects the enhancer to the promoter. The linking DNA will be important if a regulatory protein(s) binds to the enhancer and then tracks or slides along the DNA to the promoter, or if, on binding, the p... |
2795138 | Evidence for a novel mechanism of binding and release of stimuli in the primate taste bud. | In previous work, we showed that thaumatin, an intensely sweet protein, binds to certain formed elements in taste pores of Rhesus monkey foliate papillae, namely, microvilli and small vesicles shed from microvilli, in addition to amorphous secretions (Farbman et al., 1987). We suggested that the taste bud responds to a... |
2477454 | Analysis of an immunodominant region of infectious bronchitis virus. | We analyzed the antigenic fine-structure of an immunodominant region in the peplomer protein of infectious bronchitis virus. This region near the N-terminus of the S2 subunit is recognized by polyclonal antisera and by the majority of mAb that cross-react with denatured protein. Despite their involvement in neutralizat... |
2794061 | Sequence and exon-intron organization of the DNA encoding the alpha I domain of human spectrin. Application to the study of mutations causing hereditary elliptocytosis. | We have determined the exon-intron organization and the nucleotide sequence of the exons and their flanking intronic DNA in cloned genomic DNA that encodes the first 526 amino acids of the alpha I domain of the human red cell spectrin polypeptide chain. From the gene sequence we designed oligonucleotide primers to use ... |
2551922 | Lipocytes from normal rat liver release a neutral metalloproteinase that degrades basement membrane (type IV) collagen. | We report a proteinase that degrades basement-membrane (type IV) collagen and is produced by the liver. Its cellular source is lipocytes (fat-storing or Ito cells). Lipocytes were isolated from normal rat liver and established in primary culture. The cells synthesize and secrete a neutral proteinase, which by gelatin-s... |
2676983 | Cloning, characterization, and heterologous expression of the Saccharopolyspora erythraea (Streptomyces erythraeus) gene encoding an EF-hand calcium-binding protein. | The regulatory effects of Ca2+ in eucaryotic cells are mostly mediated by a superfamily of Ca2+-binding proteins (CABs) that contain one or more characteristic Ca2+-binding structural motifs, referred to as EF hands. We have cloned and sequenced the structural gene for an authentic EF-hand CAB from the spore-forming gr... |
2793825 | Structure, surface charge, and self-assembly of the S-layer lattice from Bacillus coagulans E38-66. | In freeze-etched preparations, whole cells from Bacillus coagulans E38-66 exhibited an oblique S-layer lattice (a = 9.4 nm; b = 7.4 nm; gamma = 80 degrees). The three-dimensional structure of the crystalline array was characterized by optical and computer image analysis. The lattice showed two distinctly shaped types o... |
2676125 | Molecular forensics: applications, implications and limitations. | Genotyping with DNA probes can theoretically identify each person on earth. Naturally occurring variations in the nucleotide sequence of DNA (DNA sequence polymorphisms) result in genetic differences between people. The Southern blot technique can reveal characteristic DNA banding patterns at a specific genetic locus. ... |
2550370 | Modulation of leukotriene generation by pertussis toxin. | The purpose of our study was to characterize the properties of the interaction of pertussis toxin with human polymorphonuclear leukocytes for the modulation of leukotriene generation and metabolism. The cells were stimulated with either the Ca ionophore A23187, opsonized zymosan, or the bacterial peptide formyl-methion... |
19431748 | Nature of forces stabilizing the transmembrane protein bacteriorhodopsin in purple membrane. | Analysis of the far-ultraviolet solution and the oriented-film circular dichroic (CD) spectra of the purple membrane (PM) has indicated that the alpha-helical segments of its sole protein bacteriorhodopsin (bR) can undergo a significant tilting from the normal to the membrane plane during light-dependent hydroxylamine-... |
2636899 | pH regulation of calcium recognition by an amino acid containing acyclic ionophore. | Calcium ion recognition by a dicarboxylic ionophore containing two (S)-phenylalanine residues joined via an amide bond by a flexible tri-oxa-undecanoyl bridge (Phe-3-O) has been investigated in a wide pH range (from pH 2 to 12). Experiments were performed in methanol and chloroform by 1H and 13C NMR, relaxation times a... |
2561528 | Molecular recognition between oligopeptides and nucleic acids. Specificity of binding of a monocationic bis-furan lexitropsin to DNA deduced from footprinting and 1H NMR studies. | MPE-Fe(EDTA) footprinting of a novel monocationic bis-furan lexitropsin 6 on a HindIII/EcoRI restriction fragment of pBR322 DNA revealed a series of four-base binding sites (all 5'----3') of (primary) TGTA, TGAA, AAAT, ACAA, TTAT, and (secondary) CTAA, TCGT, TGTA, GTCA, and GGTT. Thus 6 can accept a GC pair at position... |
2636898 | Compartmentation of deoxypyrimidine nucleotides for nuclear DNA replication in S phase mammalian cells. | DNA synthesis in S phase Chinese hamster embryo fibroblast cells in the presence of exogenous 3H-dUrd shows incorporation of the labeled precursor with very little dilution by the large unlabeled intracellular precursor pools. Full mixing would predict a specific activity 10-fold less than that measured. This coupled w... |
2561527 | Application of a degenerate consensus sequence to quantify recognition sites by vertebrate DNA topoisomerase II. | A consensus sequence has been derived for vertebrate topoisomerase II cleavage of DNA (Spitzner, J. R. and Muller, M. T. (1988) Nucleic Acid. Res. 16, 5533-5556). An independent sample of 65 topoisomerase II sites (obtained in the absence of topoisomerase II inhibitors) was analyzed and found to match the consensus seq... |
2636897 | Regional ligand domain is involved in scavenger receptor-mediated recognition of maleyl-albumin by rat sinusoidal liver cells. | Scavenger receptor-mediated endocytosis of maleyl-albumin was studied with rat sinusoidal liver cells. Upon maleylation of greater than 28 mol lysine residues per protein, bovine serum albumin became an active ligand. Further modification of up to 37 mol lysine residues per protein resulted in a sharp increase in the l... |
2636896 | A monoclonal antibody to a synthetic fragment of rabies virus glycoprotein binds ligands of the nicotinic cholinergic receptor. | Rabies virus glycoprotein and snake venom curaremimetic neurotoxins share a region of high homology (30-45 for neurotoxins and 190-203 for the glycoprotein) in the regions that are believed to be responsible for binding the nicotinic acetylcholine receptor. Monoclonal antibodies raised to the 190-203 synthetic fragment... |
2615390 | Molecular recognition and information gain. | Molecular recognition is considered as an information transduction process, and information theory is applied to analyze the efficiency of the information transduction during molecular recognition. It is shown that a certain amount of information is gained in the recognition process, and it can be expressed in terms of... |
2615002 | [A study of refractory pneumonia complicated by multiple organ failure in the elderly]. | A retrospective study of refractory pneumonia (n = 54), who were randomly selected from total of 657 cases of pneumonia in the elderly, was performed. These were divided into the following two groups in terms of complications. The group with multiple organ failure (MOF group; n = 30), complicated by multiple organ fail... |
2611393 | [Changes induced by sarcolysine in vivo in the composition of DNA-bound lipids in sarcoma 37]. | The two DNA fractions were isolated from sarcoma 37 by the use of the phenol method: supramolecular complex of DNA (SC DNA, 60%) and "phenol" nuclear matrix DNA (PNM DNA, 40%). The lipids in SC DNA represented of light and tightly bound components, the latter was similar to the lipid composition of PNM DNA. SC DNA cont... |
2600145 | Retention behavior of cardiac steroids using cyclodextrin in the mobile phase in high-performance liquid chromatography. | The retention behaviour of twenty cardiac steroids and four fluorescent derivatives was examined by the addition of cyclodextrin to the mobile phase in reversed-phase high-performance liquid chromatography. The addition of a suitable cyclodextrin improved the separation of isomeric cardiac steroids. The steroid A/B rin... |
2480032 | [Chemotherapy of colorectal cancer]. | Several randomized trials have shown superior response rates for 5-fluorouracil (5-FU) combined with folinic acid as compared to 5-FU alone. Both treatment regimens are well tolerated and generally can be applied in an outpatient setting. To date no other tested drug combination as methyl-CCNU (M), vincristine (O) and ... |
2586424 | [Cellular metabolic consideration in the pathophysiology and the treatment of shock]. | Shock is defined as the summation of cellular dysfunction and resultant impairment of the function in various organs. The typical such condition can be observed in shock-induced multiple organ failure (MOF). Therefore, the most effective and fundamental management against shock should be the improvement of such cellula... |
2684654 | The GAG precursor of simian immunodeficiency virus assembles into virus-like particles. | To examine the potential role of the GAG precursor polyprotein in morphogenesis and assembly of the simian immunodeficiency virus (SIV), we have expressed the gag gene of SIVMac using a baculovirus expression vector. Infection of insect cells with recombinant virus containing the entire gag gene results in high express... |
2531085 | A collagen-binding 59-kd protein (fibromodulin) is structurally related to the small interstitial proteoglycans PG-S1 and PG-S2 (decorin). | We have determined the primary structure of a 59 kd collagen binding protein which is present in many types of connective tissues, e.g. cartilage, tendon, skin, sclera and cornea. The amino acid sequence, deducted from a 2662 bp cDNA clone, predicts a 42 kd protein with a high content of leucine residues. Most of the p... |
2681643 | The potential use of cyclodextrins in parenteral formulations. | The general use of cyclodextrins in drug formulations is reviewed. The ability of cyclodextrins to form reversible inclusion complexes with many drugs can eliminate various undesirable physicochemical properties. While beta-cyclodextrin is extremely useful in many of these applications, it is toxic when given parentera... |
2553763 | Application of inclusion chromatography to the determination of in vitro metabolites of estriol. | The application of inclusion chromatography with beta-cyclodextrin as a mobile phase additive in high-performance liquid chromatography to the determination of in vitro metabolites of estriol is reported. Compared to conventional methods, the inclusion chromatography gives much more satisfactory separation of isomeric ... |
2799400 | Rupture of the diaphragm caused by blunt trauma. Review of 54 successive cases. | From 1970 to 1987, 54 patients were treated for rupture of the diaphragm as a result of blunt trauma, mostly due to road accidents. In more than 75% of the cases, other severe post-traumatic lesions were noted in association with the rupture. There were 46 lesions in the left hemidiaphragm. An early diagnosis was made ... |
2792239 | Structural analysis of lens epithelial explants induced to differentiate into fibres by fibroblast growth factor (FGF). | Recently we identified fibroblast growth factor (FGF), which is present in significant amounts in neural retinas, as a potent inducer of lens fibre differentiation in our epithelial explant cultures. Fibre differentiation was assessed by synthesis of fibre specific, proteins, beta- and gamma-crystallins, and by cell el... |
2792222 | Alkaline pH favors microtubule self-assembly in surf clam, Spisula solidissima, oocyte extracts. | Microtubule assembly in surf clam oocytes is dependent upon events that occur during fertilization. Prior to fertilization there are few, if any microtubules, but within minutes after fertilization microtubules assemble to form the meiotic apparatus. This study demonstrates that the assembly of microtubules after ferti... |
2790136 | Real-time imaging of single DNA molecules with fluorescence microscopy. | A fluorescence microscopy technique was used to image the dynamics of individual DNA molecules. Lambda, calf thymus, cosmid (circular), and T4 DNA were studied with the fluorescent dye acridine orange. Experiments with DNAase I were conducted, and the results indicate that these observations correspond to DNA molecules... |
2675955 | The First Bagshawe lecture. Towards generating cytotoxic agents at cancer sites. | Several years of experience have now accumulated in the targeting of anti-cancer agents so that we can take stock, identify problems and look for ways round them. Three major obstacles seem to limit present approaches. These are heterogeneity in the distribution of target molecules within the cancer cell population, th... |
2550937 | Single-channel recording in myelinated nerve fibers reveals one type of Na channel but different K channels. | Amphibian myelinated nerve fibers were treated with collagenase and protease. Axons with retraction of the myelin sheath were patch-clamped in the nodal and paranodal region. One type of Na channel was found. It has a single-channel conductance of 11 pS (15 degrees C) and is blocked by tetrodotoxin. Averaged events sho... |
2674939 | Design and creation of a Ca2+ binding site in human lysozyme to enhance structural stability. | A Ca2+ binding site like an EF-hand motif was designed and created in human lysozyme by replacing both Gln-86 and Ala-92 with aspartic acids by site-directed mutagenesis. The mutant human lysozyme (D86/92-lysozyme) was expressed and secreted by yeast. One Ca2+ was found to bind one molecule of the purified protein with... |
2550904 | DNA supercoiling determines the activation energy barrier for site specific recombination by Tn21 resolvase. | A kinetic analysis of site specific recombination by Tn21 resolvase has been carried out using DNA substrates of varying superhelicities. The rates for the formation of the recombinant product increased with increasing superhelicity up to a maximum value, after which further increases in superhelicity caused no further... |
2476664 | Isolation, sequence, and expression of a human keratin K5 gene: transcriptional regulation of keratins and insights into pairwise control. | The mitotically active basal layers of most stratified squamous epithelia express 10 to 30% of their total protein as keratin. The two keratins specifically expressed in these cells are the type II keratin K5 (58 kilodaltons) and its corresponding partner, type I keratin K14 (50 kilodaltons), both of which are essentia... |
2779562 | The conserved U.G pair in the 5' splice site duplex of a group I intron is required in the first but not the second step of self-splicing. | Group I self-splicing introns have a 5' splice site duplex (P1) that contains a single conserved base pair (U.G). The U is the last nucleotide of the 5' exon, and the G is part of the internal guide sequence within the intron. Using site-specific mutagenesis and analysis of the rate and accuracy of splicing of the Tetr... |
2778077 | Species identification of Aeromonas strains based on carbon substrate oxidation profiles. | Twenty clinical strains each of Aeromonas hydrophila, Aeromonas caviae, and Aeromonas sobria were evaluated for their abilities to oxidize one or more of 95 carbon sources on a GN Microplate (BIOLOG, Hayward, Calif.). Nine substrates yielded good, discriminatory values for the three species tested. The panel appears to... |
2775849 | Aggregation of amphotericin B in the presence of gamma-cyclodextrin. | The macrolide antibiotic amphotericin B (AmB) forms an inclusion complex with gamma-cyclodextrin (gamma-CDx), resulting in a molecularly dispersed state of the drug. The state of aggregation of AmB in different solvents has been studied by absorption (uv-vis) and CD spectroscopy. While in aqueous solutions AmB forms co... |
2770280 | Reduced intimal injury to canine arteries with controlled application of vessel loops. | Arterial intimal damage caused by elastic vessel loops was quantitated to determine (1) if they produce intimal injury, (2) if the injury is proportional to the force applied, and (3) if the injury is less than that produced by vascular clamps. Vessel loops were wrapped around 30 canine artery segments (5 mm in diamete... |
2768344 | Interactions and structure of the nuclear pore complex revealed by cryo-electron microscopy. | Nuclear pore complexes (NPCs) play a central role in mediating nucleocytoplasmic transport and exchange processes in eukaryotic cells. The arrangement and interactions of NPCs within amphibian nuclear envelopes have been studied using cryo-electron microscopy of unfixed and frozen hydrated specimens. The nuclear lamina... |
2670958 | Cellular heterogeneity in cultured human chondrocytes identified by antibodies specific for alpha 2(XI) collagen chains. | Collagen type XI is a component of hyaline cartilage consisting of alpha 1(XI), alpha 2(XI), and alpha 3(XI) chains; with 5-10% of the total collagen content, it is a minor but significant component next to type II collagen, but its function and precise localization in cartilaginous tissues is still unclear. Owing to t... |
2475511 | Cytokine-induced respiratory burst of human neutrophils: dependence on extracellular matrix proteins and CD11/CD18 integrins. | Human polymorphonuclear leukocytes (PMN) released large quantities of hydrogen peroxide in response to tumor necrosis factor, but only when the cells were adherent to surfaces coated with extracellular matrix proteins. The PMN did not respond when exposed to cytokines and matrix proteins in suspension, or when exposed ... |
2475510 | A calcium-binding, asparagine-linked oligosaccharide is involved in skeleton formation in the sea urchin embryo. | We have previously identified a 130-kD cell surface protein that is involved in calcium uptake and skeleton formation by gastrula stage embryos of the sea urchin Strongylocentrotus purpuratus (Carson et al., 1985. Cell. 41:639-648). A monoclonal antibody designated mAb 1223 specifically recognizes the 130-kD protein an... |
2670956 | Formation and movement of myosin-containing structures in living fibroblasts. | Gizzard myosin, fluorescently labeled with tetramethylrhodamine iodoacetamide, was microinjected into living 3T3 fibroblasts to label myosin-containing structures. The fluorophore was located predominantly on the heavy chain near the COOH terminus of the S1 head and on the 17-kD light chain. After microinjection of a t... |
2768272 | The sidedness of the COOH terminus of the acetylcholine receptor delta subunit. | The nicotinic acetylcholine receptor from Torpedo sp. occurs as a dimer, disulfide-cross-linked between delta subunits. We determined the sidedness of the COOH terminus of the acetylcholine receptor delta subunit by locating the delta-delta disulfide relative to the membrane and by identifying the Cys residue forming t... |
2504693 | Role of Myxococcus xanthus cell surface antigen 1604 in development. | The inhibition of development of Myxococcus xanthus by monoclonal antibody (MAb) 1604 has been further investigated with two MAbs produced against the affinity-purified cell surface antigen (CSA) 1604. Both of these second-generation MAbs, 4070 and 4054, reacted with the same band at 150 kilodaltons (kDa) on Western im... |
2475480 | Purification and properties of Myxococcus xanthus cell surface antigen 1604. | A cell surface antigen complex from Zwittergent-solubilized Myxococcus xanthus has been purified by immunoaffinity chromatography with monoclonal antibody (MAb) 1604 and by subsequent gel filtration. We propose that the cell surface antigen (CSA) 1604 complex participates in intercellular interactions. The apparent tot... |
2760982 | DNA binding and gene regulation by the herpes simplex virus type 1 protein ICP4 and involvement of the TATA element. | We report the results of fine mapping the sequences responsible for negative regulation of immediate-early (IE) gene 3 by its own gene product, ICP4. Affinity-purified ICP4 binds the transcriptional start site of IE gene 3 and protein-protein interactions induce a secondary mobility shift that footprints exactly as the... |
2668191 | Major integral membrane protein immunogens of Treponema pallidum are proteolipids. | A number of the major pathogen-specific immunogens of Treponema pallidum were characterized recently as amphiphilic, integral membrane proteins by phase partitioning with Triton X-114 (J. D. Radolf, N. R. Chamberlain, A. Clausell, and M. V. Norgard. Infect. Immun. 56:490-498, 1988). In the present study, we demonstrate... |
2668183 | Characterization of native and recombinant 75-kilodalton immunogens from Chlamydia trachomatis serovar L2. | A 75-kilodalton (kDa) immunogen from Chlamydia trachomatis serovar L2 was characterized. The 75-kDa protein was localized in the cytoplasm of chlamydiae and was shown to be a protein synthesized early in the developmental cycle of chlamydiae. A gene library was made by the recombinant DNA technique, using the expressio... |
2511186 | Monoclonal antibody against rat renal cell tumor-associated antigen as a new tool for the analysis of renal tumorigenesis. | A monoclonal antibody, NR-2 MAb, against one of the rat renal cell tumor-associated antigens was developed. NR-2 MAb belonged to IgM class and recognized a polypeptide of 81,000 daltons designated as NR-2 antigen, which is of non-glycoprotein nature with a pI of 4.6. NR-2 MAb was employed to probe the histogenesis of r... |
2510713 | Evidence that pyridoxal phosphate modification of lysine residues (Lys-55 and Lys-59) causes inactivation of hydroxymethylbilane synthase (porphobilinogen deaminase). | A recombinant strain of Escherichia coli has been constructed that produces approx. 200 times the amount of hydroxymethylbilane synthase found in wild-type E. coli [Hart, Abell & Battersby (1986) Biochem. J. 240, 273-276]. Enzyme purified from this strain is shown to be permanently inactivated by pyridoxal 5'-phosphate... |
2530917 | A spectrophotometric assay for the cyclization activity of cyclomaltohexaose (alpha-cyclodextrin) glucanotransferase. | A cyclomaltohexaose (alpha-cyclodextrin) determination method which is both highly reproducible and selective is described. It involves the formation of an inclusion complex between the cyclodextrin and methyl orange under conditions of low pH (1.2) and low temperature (16 degrees C) and is useful for the assay of cycl... |
2683848 | [Respiratory insufficiency and its treatment in threatened multiple organ failure]. | Multiple organ failure (MOF) is nowadays a frequent cause of death in the ICU. The pathophysiology is similar to that of ARDS: a generalized inflammatory reaction, a sepsis syndrome and a permeability disorder of the GI tract play major roles. Respiratory failure can cause or aggravate MOF, and pulmonary gas exchange m... |
2553156 | [Effector modeling of the action of ligands of GABA-receptor complex. Functional interaction of the hypothetic alcohol receptor with other subunits of the complex]. | The types of the interaction of the pharmacological effects of ethanol and barbiturate antagonists--picrotoxin, bemegride and corasol--were determined. The effect of ethanol was determined as competitive--for the convulsant effects of bicuculline, and non-competitive--for the effects of thiosemicarbazide. The indices o... |
2572080 | Molecular chaperones: proteins essential for the biogenesis of some macromolecular structures. | Many polypeptides can self-assemble into functional structures while others assemble only in the presence of additional proteins (molecular chaperones) which are not components of the final structure. We discuss here the effect that the recognition of the essential roles played by these proteins in assembly processes m... |
2677673 | Assembly properties of altered beta-tubulin polypeptides containing disrupted autoregulatory domains. | beta-Tubulin synthesis in eucaryotic cells is subject to control by an autoregulatory posttranscriptional mechanism in which the first four amino acids of the beta-tubulin polypeptide act either directly or indirectly to control the stability of beta-tubulin mRNA. To investigate the contribution of this amino-terminal ... |
2677671 | Cassette mutagenic analysis of the yeast invertase signal peptide: effects on protein translocation. | The coding sequence of the SUC2 locus was placed under the control of the constitutive ADH1 promoter and transcription terminator in a centromere-based yeast plasmid vector from which invertase is expressed in a Suc- strain of Saccharomyces cerevisiae. Mutants in the signal peptide sequence were produced by replacing t... |
2794162 | Elastophagocytosis: a non-specific reaction pattern associated with inflammatory processes in sun-protected skin. | Four cases characterized by primary inflammatory processes localized to sun-shielded skin were observed to have associated phagocytosis of elastic fibers by multinucleate histiocytic giant cells. These findings support the idea that this reaction pattern may occur non-specifically, at least in some instances, in sun-pr... |
2676513 | Nobel lecture. A structural basis of light energy and electron transfer in biology. | Aspects of intramolecular light energy and electron transfer will be discussed for three protein--cofactor complexes, whose three-dimensional structures have been elucidated by X-ray crystallography: components of light-harvesting cyanobacterial phycobilisomes; the purple bacterial reaction centre; and the blue multi-c... |
2790384 | Effects of N-ethylmaleimide on 5-hydroxytryptamine transport and sodium content in rabbit platelets. | 1. The present study analysed the mechanism underlying the inhibitory action of N-ethylmaleimide (NEM) on the 5-hydroxytryptamine (5-HT) uptake by blood platelets. 2. Rabbit platelets suspended in protein-free buffer were first preincubated for 45 min in the absence and presence of NEM (20 to 160 microM) or ouabain (0.... |
2528566 | Crown ethers as ligands for high-performance liquid chromatography of proteins and nucleic acids. | By immobilization of the crown ether 1,10-diaza-18-crown-6 to different porous and non-porous, epoxy-activated supports, a chromatographic sorbent was prepared, which, mediated by potassium ions, can be used for the separation of both nucleic acids and proteins. Model experiments have been carried out with ribonucleic ... |
2776185 | Changes in lectin binding of lumbar dorsal root ganglia neurons and peripheral axons after sciatic and spinal nerve injury in the rat. | The effects of chronic lesions of rat lumbar spinal or sciatic nerves on the binding of Glycine max (soybean) agglutinin to galacto-conjugates, in small- and medium-size primary sensory neurons of the L4 and L5 dorsal root ganglia, were examined over a 580-day period. Spinal nerve section resulted in a marked decrease ... |
2775834 | Form birefringence of muscle. | We investigate the sensitivity of measurements of muscle birefringence to cross-bridge dynamics in the resting, active, and rigor states. The theory of form birefringence is reviewed, and an optical model is constructed for the form birefringence of muscle. Values for the parameters in the model are selected or deduced... |
2549220 | GABA regulation of circadian responses to light. I. Involvement of GABAA-benzodiazepine and GABAB receptors. | Light-induced phase shifts of the circadian locomotor rhythm of hamsters can be blocked by agents that alter GABA neurotransmission. The GABA antagonist bicuculline blocks phase delays induced by light and the benzodiazepine diazepam, which can potentiate GABA activity, blocks light-induced phase advances. In the exper... |
2548736 | Site-specific recombination by Tn3 resolvase: topological changes in the forward and reverse reactions. | Site-specific recombination catalyzed by Tn3 resolvase proceeds with a linkage change, delta Lk, of +4 in the forward resolution reaction and -4 in the catenane fusion reverse reaction. The reverse reaction occurs only at low superhelical densities and gives unknotted circular products, consistent with plectonemic and ... |
2504155 | Evidence for the formation of covalent bonds between macromolecules in the domain of the wall of Candida albicans mycelial cells. | An O-glycosylated mannoprotein, after its incorporation into the wall, showed an increase in its molecular weight, due at least to its association with N-glycosidic sugar chain(s). This was shown by rendering the material soluble after partial degradation of the wall structure. At present it is unknown whether this phe... |
2762319 | Actin filaments mediate Dictyostelium myosin assembly in vitro. | Because myosin thick filaments form in the actin-rich cortex of nonmuscle cells, we have examined the role of Dictyostelium actin filaments in the assembly of Dictyostelium myosin (type II). Fluorescence energy transfer and light-scattering assembly assays indicate that self-association of Dictyostelium myosin into bip... |
2548196 | Recombination of knotted substrates by Tn3 resolvase. | We studied the site orientation specificity for recombination by purified Tn3 resolvase. With standard plasmid substrates, resolvase acts only on directly repeated recombination sites. Knotting, however, makes inverted site substrates equally efficient. The structure of the knotted products of recombination shows that ... |
2762300 | Effects of lipid packing on polymorphic phase behavior and membrane properties. | The self assembly of phospholipid molecules in the bilayer form was considered in terms of equivalent molecular shapes representing intermolecular forces. The equivalent size of each phospholipid headgroup was approximated by the net atomic volume plus the volume of the associated water molecules, which was derived fro... |
2762299 | Enzymes work by solvation substitution rather than by desolvation. | Considerable attention has recently been drawn to the hypothesis that enzymes catalyze their reactions by displacing solvent and creating an environment similar to the gas phase for the reacting substrates. This "desolvation hypothesis" is reexamined in this paper by defining a common reference energy for reactions in ... |
2788277 | Role of capsid precursor processing and myristoylation in morphogenesis and infectivity of human immunodeficiency virus type 1. | The effects on human immunodeficiency virus type 1 virion morphogenesis and on virus replication of mutations that affect posttranslational processing of the capsid precursor protein are described. A change in the glycine residue at position two from the N terminus abolishes the myristoylation of the precursor proteins... |
2503822 | Cloning of the immunological repertoire in Escherichia coli for generation of monoclonal catalytic antibodies: construction of a heavy chain variable region-specific cDNA library. | Efficient generation of catalytic antibodies is uniquely dependent on the exact nature of the binding interactions in the antigen-antibody complex. Current methods for generation of monoclonal antibodies do not efficiently survey the immunological repertoire and, therefore, they limit the number of catalysts that can b... |
2760115 | Expression and analysis of COOH-terminal deletions of the human thrombospondin molecule. | Thrombospondin (TSP) is a homotrimeric extracellular glycoprotein with a subunit molecular mass of 140 kD. The subunits have a modular or domain-like structure and are held together by interchain disulphide bonds. A number of domains have been identified including those for the binding of collagen, fibrinogen, and hepa... |
2755156 | Elastofibroma dorsi: benign chest wall tumor. | Elastofibroma dorsi was diagnosed in seven patients at the Columbia-Presbyterian Medical Center between 1976 and 1986. The ages of the patients ranged from 6 to 79 years (mean 49.3 years). No sex predominance was seen. Five cases of unilateral subscapular tumor and two cases of bilateral masses were identified. Four pa... |
2526811 | Functional consequences of alterations to amino acids located in the catalytic center (isoleucine 348 to threonine 357) and nucleotide-binding domain of the Ca2+-ATPase of sarcoplasmic reticulum. | The sequence of 10 amino acids (ICSDKTGTLT357) at the site of phosphorylation of the rabbit fast twitch muscle Ca2+-ATPase is highly conserved in the family of cation-transporting ATPases. We changed each of the residues flanking Asp351, Lys352, and Thr353 to an amino acid differing in size or polarity and assayed the ... |
2546914 | Purification and characterization of S-adenosyl-L-methionine: uroporphyrinogen III methyltransferase from Pseudomonas denitrificans. | S-Adenosyl-L-methionine:uroporphyrinogen III methyltransferase (SUMT), the enzyme of the cobalamin biosynthetic pathway which catalyzes C methylation of uroporphyrinogen III, was purified about 150-fold to homogeneity from extracts of a recombinant strain of Pseudomonas denitrificans derived from a cobalamin-overproduc... |
2545916 | Phorbol ester-inducible T-cell-specific expression of variant mouse mammary tumor virus long terminal repeats. | Acquired proviruses of mouse mammary tumor virus (MMTV) in T-cell leukemias of male GR mice have rearrangements in the U3 region of their long terminal repeats (LTR). In contrast to the endogenous nonrearranged MMTV proviruses, these mutated copies are highly expressed in leukemic T cells. To investigate whether the se... |
16594056 | Self-assembly of synthetic phytochrome holoprotein in vitro. | The phytochrome holoprotein of plants requires a covalently bound linear tetrapyrrole (bilin) prosthetic group for its photoreceptor function. Here we show that synthetic phytochrome apoprotein prepared by transcription and translation of an Avena phytochrome cDNA construct combines in vitro with phycocyanobilin, an an... |
2636895 | Molecular recognition between oligopeptides and nucleic acids. Sequence specific binding of (4S)-(+)- and (4R)-(-)-dihydrokikumycin B to DNA deduced from 1H NMR, footprinting studies and thermodynamic data. | The sequence specific binding of the antibiotic (4S)-(+)-dihydrokikumycin B and its (4R)-(-) enantiomer, [(S)-1 and (R)-1, respectively] to DNA were characterized by DNase I and MPE footprinting, calorimetry, UV spectroscopy, circular dichroism, and 1H NMR studies. Footprinting analyses showed that both enantiomers [(S... |
2561526 | Evidence for the presence of disulfide bridges in opioid receptors essential for ligand binding. Possible role in receptor activation. | The mobility of purified mu opioid binding protein in SDS-polyacrylamide gek electrophoresis is sensitive to the presence of reducing agents. In the presence of increasing concentrations of DTT the apparent molecular weight increases in a stepwise fashion from 53 kDa to 65 kDa. This reduction in mobility is attributed ... |
2700071 | Definition of the phage G13 receptor as structural domains of trisaccharides in Salmonella and Escherichia coli core oligosaccharides. | The interaction between phage G13 and different bacterial and synthetic oligosaccharides has been studied using equilibrium dialysis inhibition. The results, and conformational analysis of the oligosaccharides, make us conclude that the phage G13 carbohydrate receptor is a conformational domain involving three sugar re... |
2700070 | The conformation of core oligosaccharides from Escherichia coli and Salmonella typhimurium lipopolysaccharides as predicted by semi-empirical calculations. | The preferred conformation of the hexose and heptose regions of core saccharides from Enterobacteriaceae lipopolysaccharides was calculated. The Hard Sphere Exo Anomeric (HSEA) approach was used and the minimum energy conformation of the Salmonella typhimurium and Escherichia coli R1, R2, R3, R4 and K12 cores calculate... |
2700069 | Interaction between phage G13 and its oligosaccharide receptor studied by equilibrium dialysis. | The reversible binding of phage G13, a phi X174-like single-strand DNA phage, to a 3H-labelled nonasaccharide from the lipopolysaccharide of its natural host Escherichia coli C was studied with equilibrium dialysis. The binding constant (Ka) was determined to 1.3 x 10(7) M-1 in Scatchard and Lineweaver-Burk plots. Appr... |
2636894 | Molecular recognition in synthetic polymers. Enantiomeric resolution of amide derivatives of amino acids on molecularly imprinted polymers. | Molecular imprints were prepared using L-phenylalanine anilide as the print molecule and methacrylic acid as the functional monomer. Methacrylic acid interacts ionically with the primary amine of the print molecule and via hydrogen bonding with the amide function. In the HPLC mode such polymers were shown to exhibit ef... |
2619427 | Pharmacokinetics of dipyridamole-beta-cyclodextrin complex in dogs. | Plasma concentrations and urinary and fecal excretion of intact dipyridamole were followed in dogs after oral administration of dipyridamole-beta-cyclodextrin complex (dip-beta-CD) (capsules containing 37.5 and 75 mg of active principle), of commercial dipyridamole and of dipyridamole. HCl (tablets and capsules of 75 m... |
2610988 | Structure of antischistosome compounds. V 1,6-Hexanediylbis(triphenylphosphonium) dibromide. | C42H42P2(2+).2Br-, Mr = 768.6, triclinic, P1, a = 13.328 (2), b = 23.110 (3), c = 9.417 (1) A, alpha = 90.75 (1), beta = 109.62 (1), gamma = 91.23 (1) degrees, V = 2730.86 A3, Z = 3, Dx = 1.402 g cm3, graphite-monochromatized Cu K alpha radiation, lambda = 1.5418 A, mu = 52.0 cm-1, F(000) = 1182, T = 292 K. Final R = 0... |
2683986 | Treatment of advanced colorectal cancer. | Colorectal cancer is one of the most chemotherapy-resistant human malignancies. After 30 years of intensive research, 5-fluorouracil (5-FU) remains the most frequently used drug. The expected response rate is of about 15% without any proven benefit in survival. One of the combination most investigated recently has been... |
2798316 | Testosterone in a cyclodextrin-containing formulation: behavioral and physiological effects of episode-like pulses in rats. | Testosterone, administered in the form of an inclusion complex with 2-hydroxypropyl-beta-cyclodextrin by subcutaneous injection, enters the circulation in a manner markedly similar to the natural episodic release by the testes. The effects of a regimen of once-a-day administration of complexed testosterone to adult (ca... |
2551668 | Sequence analysis of alpha 1(VI) and alpha 2(VI) chains of human type VI collagen reveals internal triplication of globular domains similar to the A domains of von Willebrand factor and two alpha 2(VI) chain variants that differ in the carboxy terminus. | Amino acid sequences of human collagen alpha 1(VI) and alpha 2(VI) chains were completed by cDNA sequencing and Edman degradation demonstrating that the mature polypeptides contain 1009 and 998 amino acid residues respectively. In addition, they contain small signal peptide sequences. Both chains show 31% identity in t... |
2551666 | Multifunctional receptor model for dioxin and related compound toxic action: possible thyroid hormone-responsive effector-linked site. | Molecular/theoretical modeling studies have revealed that thyroid hormones and toxic chlorinated aromatic hydrocarbons of environmental significance (for which dioxin or TCDD is the prototype) have similar structural properties that could be important in molecular recognition in biochemical systems. These molecular pro... |
2506660 | Collagen banded fibril structure and the collagen-platelet reaction. | Bovine hide collagen dispersions were swollen in the pH range 1.6-7.0, treated with glutaraldehyde, and dialyzed to neutral pH. The intensity with which these collagens reacted with human platelets in plasma was studied by aggregometry and scanning electron microscopy. Collagen swollen at a pH below 4.25 +/- 0.30 and t... |
2780976 | [Changes in the composition of DNA-bound nonhistone protein in the thymus and liver of gamma-irradiated rats]. | A supramolecular DNA complex (SC DNA) and DNA of a phenol nuclear matrix (PNM DNA) were extracted, by the phenol method, from rat thymus and liver 15 min following 10 Gy gamma-irradiation. The method of electrophoresis in polyacrylamide gel was used to study a composition of nonhistone proteins firmly bound to these DN... |
2550795 | Dictyostelium discoideum myosin: isolation and characterization of cDNAs encoding the regulatory light chain. | Phosphorylation of the regulatory light chains (RMLC) of nonmuscle myosin can increase the actin-activated ATPase activity and filament formation. Little is known about these regulatory mechanisms and how the RMLC are involved in ATP hydrolysis. To better characterize the nonmuscle RMLC, we isolated cDNAs encoding the ... |
2775240 | Reconstitution of intermediate filaments from a higher plant. | Immunological studies have shown that plants contain intermediate-filament antigens, but it is not known whether these proteins are capable in themselves of forming filaments. To address this problem, a detergent-resistant and high-salt-insoluble fraction from carrot (Daucus carota L.) suspension cells was solubilized ... |
2476034 | Astrocytes and microglia in human brain share an epitope recognized by a B-lymphocyte-specific monoclonal antibody (LN-1). | A B-lymphocyte-specific mouse monoclonal antibody, LN-1, recognizes two morphologic classes of glial cells in human brain. The nature and duration of tissue fixation and processing are critical in the detection of the two cell types. In tissue that is lightly fixed, LN-1 recognizes astrocytes. The astrocytic nature of ... |
2671377 | Role of substrate binding forces in exchange-only transport systems: II. Implications for the mechanism of the anion exchanger of red cells. | The transition-state theory of exchange-only membrane transport is applied to experimental results in the literature on the anion exchanger of red cells. Two central features of the system are in accord with the theory: (i) forming the transition state in translocation involves a carrier conformational change; (ii) sub... |
2762124 | Construction of a 42 base pair double stranded DNA microcircle. | A procedure for the construction of double stranded DNA microcircles is described that overcomes the natural limits of established circularization procedures. Starting with two synthetic oligonucleotides which are able to form dumbbell shaped structures, two subsequent ligation reactions yield a microcircle of double s... |
2503395 | Trapping of transiently formed quinone methide during enzymatic conversion of N-acetyldopamine to N-acetylnorepinephrine. | We have demonstrated that quinone methide formation is an important aspect of insect physiology and proposed that enzymatically generated quinone methides react nonenzymatically with water or other nucleophiles to form Michael-1,6-addition products [(1988) Adv. Insect Physiol. 21, 179-231; (1989) J. Cell. Biochem. supp... |
2547177 | Evidence for prolonged suppression of stress-induced release of adrenocorticotropic hormone and corticosterone with a brain-enhanced dexamethasone-redox delivery system. | We have developed a redox system for brain-enhanced delivery of dexamethasone based on an interconvertible dihydropyridine in equilibrium pyridinium salt carrier. Dexamethasone, when combined with the lipoidal carrier, readily crosses the blood-brain barrier. The carrier, when oxidized, reduces its rate of exit from th... |
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