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2188948 | The folding properties of the Escherichia coli maltose-binding protein influence its interaction with SecB in vitro. | It has been proposed that the cytoplasmic SecB protein functions as a component of the Escherichia coli protein export machinery by serving as an antifolding factor that retards folding of the precursor maltose-binding protein (preMBP) into a translocation-incompetent form. In this study, it was found that SecB directl... |
2160593 | Evidence that replication initiates at only some of the potential origins in each oligomeric form of bovine papillomavirus type 1 DNA. | In a subclone of ID13 mouse fibroblasts latently infected with bovine papillomavirus type 1 (BPV-1) DNA, the viral genome occurred as a mixture of extrachromosomal circular monomers and oligomers. Multiple copies were also associated with the host cell genome, predominantly at a single site in a head-to-tail tandem arr... |
2160588 | Inhibition of topoisomerase II does not inhibit transcription of RNA polymerase I and II genes. | Injection of VM-26 (teniposide) into Xenopus oocytes inhibits the activity of topoisomerase II but does not inhibit transcription by RNA polymerases I and II. A specific assay for topoisomerase II, resolution of catenated DNA molecules into product rings, was used to quantitate VM-26 inhibition in vivo. When catenanes ... |
2160586 | Nucleosome assembly of simian virus 40 DNA in a mammalian cell extract. | We report here a mammalian cell-free system that can support chromatin assembly. Effective nucleosome assembly in HeLa cell extracts occurred at 125 to 200 mM KCl or potassium glutamate. At this physiological K+ ion concentration, two types of chromatin assembly were observed. The first was interfered with by Mg2+. Oth... |
2187810 | Detection of antigens with affinity for host cell membrane polypeptides in culture supernatants of Trypanosoma cruzi. | Parasite antigens which bind to host cell molecules of approximately 32 and 34 kilodaltons (kDa) were identified in supernatant fluids obtained from axenic cultures of Trypanosoma cruzi. These parasite components were first detected in culture supernatants obtained after 2 weeks in culture. Immunoblot analysis of cultu... |
2341166 | Roles of the disulfide bond and the carboxy-terminal region of the S1 subunit in the assembly and biosynthesis of pertussis toxin. | A Bordetella pertussis expression system was developed to analyze the structure-function relationship, in vivo assembly, and biosynthesis of pertussis toxin. The toxin structural gene was first deleted from the B. pertussis chromosome; into the resulting B. pertussis strain the toxin gene was introduced on a low-copy-n... |
2339699 | Molecular cloning of alpha 5(IV) collagen and assignment of the gene to the region of the X chromosome containing the Alport syndrome locus. | Type IV collagen is a major structural component of basement membranes. Four constituent polypeptides have been described and characterized to different degrees. Whereas the primary structure of the alpha 1(IV) and alpha 2(IV) chains has been completely established, only short protein sequences have been reported for t... |
2159540 | Herpes simplex virus type 1 encodes two Fc receptors which have different binding characteristics for monomeric immunoglobulin G (IgG) and IgG complexes. | Two herpes simplex virus type 1 glycoproteins, gE and gI, have been shown to form a complex that binds the Fc domain of immunoglobulin G (IgG). We demonstrate that this complex is required for the binding of monomeric nonimmune IgG but that gE alone is sufficient for binding polymeric IgG in the form of IgG complexes. ... |
2159536 | Rotavirus proteins VP7, NS28, and VP4 form oligomeric structures. | Sucrose gradient sedimentation analysis of rotavirus SA11-infected Ma104 cells revealed the presence of oligomers of VP7, the structural glycoprotein, and NS28, the nonstructural glycoprotein. Cross-linking the proteins, either before or after sucrose gradient centrifugation, stabilizes oligomers, which can be analyzed... |
19431758 | In search of a putative long-lived relaxed radical pair state in closed photosystem II: Kinetic modeling of picosecond fluorescence data. | The concept of a relaxed radical pair state in closed photosystem (PS) II centers (first quinone acceptor reduced) is critically examined on the basis of chlorophyll fluorescence decay data of the green alga Scenedesmus obliquus. Global analysis resulting in the decay-associated fluorescence spectra from closed PS II c... |
17809904 | Chiral metal complexes as discriminating molecular catalysts. | As molecular recognition continues to gain importance in the biological and physical sciences as well as in the technologies of molecular electronics and optics, so has the need for efficient syntheses of chiral molecules. Chemists are fulfilling this need through use of chiral organometallic molecules. These chiral me... |
1720029 | Molecular recognition between ligands and nucleic acids: novel pyridine- and benzoxazole-containing agents related to Hoechst 33258 that exhibit altered DNA sequence specificity deduced from footprinting analysis and spectroscopic studies. | The syntheses of certain analogues of the DNA minor groove binding agent Hoechst 33258 designed to exhibit altered sequence recognition are described. The structural modifications include the following: substitution of pyridine for the benzene ring of the benzimidazole moiety, replacement of one benzimidazole unit by a... |
2131839 | Mode of action of saframycin antitumor antibiotics: sequence selectivities in the covalent binding of saframycins A and S to deoxyribonucleic acid. | The sequence-preferential reversible covalent binding of certain saframycin antitumor antibiotics from Streptomyces lavendulae has been examined by complementary-strand methidium propyl-EDTA (MPE) footprinting on an EcoRI/HindIII restriction fragment of pBR322 DNA under several experimental conditions. A buffer at pH 7... |
2207188 | [Absence of small-angle maximums on the x-ray images of ocular lens tissue]. | X-ray small-angle scattering study of bovine lens tissue was carried out. It was shown that X-ray patterns of lens cortical and nuclear native tissues did not contain the small-angle maxima. The maximum in the range of 15-20 nm Bragg distance appeared as a result of the lens tissue partial dehydration. Earlier such max... |
2168789 | [Clinical patterns and stages of multiple organ failure in the elderly]. | Multiple organ failure in the elderly (MOFE) is a new clinical syndrome different from multiple organ failure (MOF) caused by trauma occurring most often in young and mid-aged persons. The authors retrospectively analysed 158 cases of MOFE hospitalized in the past 12 years and commented on its definition, diagnostic cr... |
2386074 | Interaction of some benzothiadiazine diuretics with beta-cyclodextrin. | The interaction of three structurally related benzothiadiazine diuretics, viz., hydroflumethiazide, bendrofluazide and cyclopenthiazide wit beta-cyclodextrin was investigated. The study aimed at enhancing the solubility of these poorly soluble drugs via inclusion complexation with beta-cyclodextrin, Solubility measurem... |
2198939 | Preparation and properties of recombinant DNA derived tobacco mosaic virus coat protein. | Recombinant DNA derived tobacco mosaic virus (vulgare strain) coat protein (r-TMVP) was obtained by cloning and expression in Escherichia coli and was purified by column chromatography, self-assembly polymerization, and precipitation. SDS-PAGE, amino terminal sequencing, and immunoblotting with polyclonal antibodies ra... |
2165503 | Displacement chromatography on cyclodextrin-silicas. III. Enantiomer separations. | The feasibility of preparative enantiomer separations by displacement chromatography on analytical-scale beta-cyclodextrin-silica columns, operated in the reversed-phase mode, was demonstrated using the enantiomers of mephobarbital, hexobarbital, dansylleucine, dansylvaline and dansylphenylalanine as model solutes. The... |
2369620 | Solvent effect on binding thermodynamics of biopolymers. | The indirect solvent-induced effect on the free energy of binding of biopolymers is examined within the framework of classical statistical mechanics. We focus specifically on the role of the solute-solvent hydrogen bonding. In particular, we have estimated the first order solvent effect on the indirect interaction betw... |
2367318 | Nasal absorption enhancement of 17 beta-estradiol by dimethyl-beta-cyclodextrin in rabbits and rats. | A new formulation for nasal administration containing 17 beta-estradiol (E2) with dimethyl-beta-cyclodextrin (DM beta C) as a solubilizer and absorption enhancer is described. Nasal administration of this E2-DM beta C formulation gave a significantly higher E2 absorption than an E2 suspension in both rabbits and rats. ... |
2367316 | Effect of cyclodextrin derivatives on indomethacin stability in aqueous solution. | The effect of various cyclodextrins (CD) and cyclodextrin derivatives on indomethacin stability in phosphate buffer, pH 7.4, was investigated. The influence of CD-ring size, type of substituent, degree of substitution, substitution pattern, and influence of CD concentration were monitored. The indomethacin complex in s... |
2194563 | Temperature-dependent conformational changes in the bacteriopheophytins of Rhodobacter sphaeroides reaction centers. | Resonance Raman (RR) spectra are reported for the photosynthetic reaction center (RC) protein from Rhodobacter sphaeroides 2.4.1. The spectra were obtained with a variety of excitation wavelengths, spanning the UV, violet, and yellow-green regions of the absorption spectrum, and at a number of temperatures ranging from... |
2363515 | Polar-liquid, derivatized cyclodextrin stationary phases for the capillary gas chromatography separation of enantiomers. | A new class of hydrophilic, relatively polar liquid, cyclodextrin (CD) derivatives have been used as highly selective chiral stationary phases (CSPs) for capillary gas chromatography (GC). Several possible requirements for liquidity in CD derivatives are discussed. O-(S)-2-Hydroxypropyl derivatives of alpha-, beta-, an... |
2362183 | Asymmetrical properties of the Na-Ca exchanger in voltage-clamped, internally dialyzed squid axons under symmetrical ionic conditions. | In this work we have investigated whether the asymmetrical properties of the Na/Ca exchange process found in intact preparations are intrinsic to the exchange protein(s) or the result of the asymmetric ionic environment normally prevailing in living cells. The activation of the Na/Ca exchanger by Ca2+ ions, monovalent ... |
2163225 | Beta-cyclodextrin bonded silica for direct injection analysis of drug enantiomers in serum by liquid chromatography. | A new beta-cyclodextrin (CD) bonded silica has been designed for direct injection analysis of drug enantiomers in serum for liquid chromatography. The new beta-CD bonded silica is synthesized by three steps: introduction of a 3-glycidoxypropyl phase, introduction of a beta-CD carbamate-bonded phase, and hydrolysis of t... |
2162012 | Anti-opioid receptor antibody recognition of a binding site on brain and leukocyte opioid receptors. | Opioid receptors reportedly exist on neuronal tissue of central and peripheral origin as well as on cells of the immune system. Previously, an opioid receptor has been purified from the neuroblastoma x glioma hybrid cell line, NG108-15 cells. In an effort to compare these results with opioid receptors isolated from pri... |
2352422 | Hepatocellular dysfunction occurs early after hemorrhage and persists despite fluid resuscitation. | The liver is a major organ involved in multiple organ failure (MOF) following hemorrhage and trauma. However, it is not known if active hepatocellular membrane transport, measured by in vivo indocyanine green (ICG) clearance, is depressed after hemorrhage and if it persists after resuscitation. To study this, rats were... |
2351723 | Simple, efficient purification of filamentous hemagglutinin and pertussis toxin from Bordetella pertussis by hydrophobic and affinity interaction. | Two major antigens of Bordetella pertussis, filamentous hemagglutinin (FHA) and pertussis toxin (PT), were efficiently purified from culture filtrate by exploiting their relative hydrophobicities and differences in affinity to sialic acid-containing protein. High yields of FHA (40 to 80 mg/liter) and PT (8 to 16 mg/lit... |
1972028 | Biosynthetic studies of substituent homologation in bacteriochlorophylls c and d. | Administration of carbon-13 and carbon-14 labeled glutamate, glycine, and methionine to Chlorobium vibrioforme forma thiosulfatophilum strain D have demonstrated operation of the C5 and C1 metabolic pathways in bacteriochlorophyll c and bacteriochlorophyll d biosynthesis in this organism, with glutamate providing the d... |
2189401 | Evidence for nonintercalative complexes formed from the reversible binding of benzo[a]pyrene metabolites to closed-circular, single-stranded M13mp19 DNA. | The fluorescence excitation spectrum of complexes formed from the reversible binding of the proximate carcinogen, trans-7,8-dihydroxy-7,8-dihydro-benzo[a]pyrene (BP78D) to closed-circular, single-stranded, viral M13mp19 DNA (SS M13 DNA) exhibits a red-shift of 5 nm compared to the spectrum of BP78D measured without DNA... |
2187872 | Undulin, an extracellular matrix glycoprotein associated with collagen fibrils. | Undulin, a novel noncollagenous extracellular matrix protein, was isolated from skin and placenta. In polyacrylamide gels most of the unreduced protein migrates with Mr above 1,000,000 yielding bands A (Mr 270,000), B1 (Mr 190,000), and B2 (Mr 180,000) after reduction. Undulin is biochemically and immunochemically dist... |
2340344 | Probing the structure of diacetylenic phospholipid tubules with fluorescent lipophiles. | Novel lipid structures called tubules can be prepared from diacetylenic phospholipids. We have prepared fluorescent tubules from mixtures of 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphatidylcholine and 1 mol% fluorescent lipophiles to study the characteristics of the tubule lipid matrix. We have found that once f... |
2339983 | Elements of secondary structure in a human epithelial mucin core peptide fragment. | The protein core of human epithelial mucin has previously been shown to consist of tandem repeats of a 20-amino-acid sequence that carries the epitopes for a number of tumour-marking monoclonal antibodies. High-field n.m.r. studies have now been undertaken on an 11-amino-acid fragment of this sequence dissolved in dime... |
1692677 | Antigenic nature of the chloride-stimulated cellobiosidase and other cellulases of Fibrobacter succinogenes subsp. succinogenes S85 and related fresh isolates. | Polyclonal and monoclonal antibodies to the Cl-stimulated cellobiosidase of Fibrobacter succinogenes subsp. succinogenes S85 reacted with numerous proteins of both higher and lower molecular weights from F. succinogenes subsp. succinogenes S85, but not with Escherichia coli proteins, and only one protein each from Buty... |
2140192 | Activation of ara operons by a truncated AraC protein does not require inducer. | The araC gene of Escherichia coli encodes a protein that binds the inducer L-arabinose to activate the transcription of three ara operons. In a study to determine the functional domains within the AraC protein, we have generated a set of overlapping deletions from the proximal end of the araC gene. We found that the re... |
2110570 | Brownian motion of inert tracer macromolecules in polymerized and spontaneously bundled mixtures of actin and filamin. | By use of light microscopy and fluorescence photobleaching recovery, we have studied (a) structures that form in a system composed of copolymerized rabbit muscle actin and chicken gizzard filamin and (b) the Brownian motion of inert tracer macromolecules in this matrix. We have used as tracers size-fractionated fluores... |
1970824 | Identification of a novel nucleotide-sensitive microtubule-binding protein in HeLa cells. | A protein of Mr 170,000 (170K protein) has been identified in HeLa cells, using an antiserum raised against HeLa nucleotide-sensitive microtubule-binding proteins. Affinity-purified antibodies specific for this 170K polypeptide were used for its characterization. In vitro sedimentation of the 170K protein with taxol mi... |
2185246 | Kinetic analysis of the pre-equilibrium steps in the self-assembly of RecA protein from Escherichia coli. | Total intensity light scattering is employed to investigate the self-assembly kinetics of RecA protein. Reaction conditions are employed where the kinetics of self-assembly are slow enough to yield reliable scattered intensity measurements over the range of scattering angles from 40 to 130 degrees as a function of time... |
2110150 | Highly repetitive DNA sequences in cyanobacterial genomes. | We characterized three distinct families of repeated sequences in the genome of the cyanobacterium Calothrix sp. strain PCC 7601. These repeated sequences were present at a level of about 100 copies per Calothrix genome and consisted of tandemly amplified heptanucleotides. These elements were named short tandemly repea... |
2332405 | Characterization of the surface layer glycoprotein of Clostridium symbiosum HB25. | The cell surface of Clostridium symbiosum HB25 is covered by a squarely arranged surface layer (S-layer) glycoprotein. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the sodium dodecyl sulfate-soluble whole-cell extract showed the presence of several high-molecular-weight protein bands in a narrow range (... |
2185225 | Site-directed mutations in the repA C-terminal region of plasmid Rts1: pleiotropic effects on the replication and autorepressor functions. | We induced site-directed mutations near the 3' terminus of the gene repA, which encodes the protein of 288 amino acid residues essential for plasmid Rts1 replication, and obtained seven repA mutants. Three of them contained small deletions at the 3' terminus. Mutant repAz delta C4, which encodes a RepA protein that lac... |
2158968 | Alkaline, acid, and neutral phosphatase activities are induced during development in Myxococcus xanthus. | One of the signals that has been reported to be important in stimulating fruiting body formation of Myxococcus xanthus is starvation for phosphate. We therefore chose to study phosphatase activity during M. xanthus development. Many phosphatases can cleave the substrate p-nitrophenol phosphate. Using this substrate in ... |
2184032 | A major glycoprotein of the nuclear pore complex is a membrane-spanning polypeptide with a large lumenal domain and a small cytoplasmic tail. | One of a small number of polypeptides of the nuclear pore complex that have been identified is a major glycoprotein called gp210. Since it is very resistant to chemical extractions from membranes, gp210 was suggested to be integrated into nuclear membranes. In this study we have determined the membrane topology of this... |
2325644 | A constitutive damage-specific DNA-binding protein is synthesized at higher levels in UV-irradiated primate cells. | Using a DNA band shift assay, we have identified a DNA-binding protein complex in primate cells which is present constitutively and has a high affinity for UV-irradiated, double-stranded DNA. Cells pretreated with UV light, mitomycin C, or aphidicolin have higher levels of this damage-specific DNA-binding protein compl... |
2323818 | Characterization of genetically inactivated pertussis toxin mutants: candidates for a new vaccine against whooping cough. | the introduction of two amino acid substitutions within the enzymatically active subunit S1 of pertussis toxin (PT) abolishes its ADP-ribosyltransferase activity and toxicity on CHO cells (Pizza et al., Science 246:497-500, 1989). These genetically inactivated molecules are also devoid of other in vivo adverse reaction... |
11607077 | Evidence that a distribution of bacterial reaction centers underlies the temperature and detection-wavelength dependence of the rates of the primary electron-transfer reactions. | The rates of the primary electron-transfer processes in Rhodobacter sphaeroides reaction centers have been examined in detail by using 150-fs excitation flashes at 870 nm. At room temperature the apparent time constants for both initial charge separation (P* --> P+BPhL-) and subsequent electron transfer (P+BPhL- --> P+... |
11607076 | Supramolecular arrangement of Rhodospirillum rubrum B880 holochrome as studied by radiation inactivation and electron paramagnetic resonance. | Oxidation of the B880 antenna holochrome gives rise to a 3.8-G linewidth electron paramagnetic resonance (EPR) signal that is considerably narrower than the 13-G signal of monomeric bacteriochlorophyll (Bchl) cation. Radiation inactivation was used to verify a model according to which this linewidth narrowing is due to... |
1976746 | Detection of human papillomavirus (HPV) DNA in laryngeal papilloma. | Laryngeal papillomas are troublesome benign tumors of the larynx. According to their biological behavior, there are two types of laryngeal papillomas--the juvenile and adult types. Two samples of adult-type and five samples of juvenile-type laryngeal papilloma specimens were studied using the Southern blot technique wi... |
2206373 | [Stability examination of the inclusion compounds of 8 Chinese medicinal volatile oils with beta-cyclodextrin]. | The content, hence the stability of volatile oils and their main components in the inclusion compounds of 8 Chinese medicinal volatile oils with beta-cyclodextrin have been examined with different storage times. The 8 Chinese medicines are Vitex negundo var. heterophylla, Notopterygium incisum, Alpinia officinarum, Atr... |
2384532 | Collagen fibrillogenesis in vitro: interaction of types I and V collagen regulates fibril diameter. | The small-diameter fibrils of the chick corneal stroma are heterotypic, composed of both collagen types I and V. This tissue has a high concentration of type V collagen relative to other type I-containing tissues with larger-diameter fibrils, suggesting that heterotypic interactions may have a regulatory role in the co... |
2379443 | [Plasma level and effects of thromboxane A2 and 6-keto-PGF1 alpha in patients with acute obstructive suppurative cholangitis]. | The changes of the plasma thromboxane B2 (TXB2) and 6-keto-PGF1 alpha, the stable metabolites of TXA2 and PGI2, respectively and their effects on platelet counts, platelet aggregation and hypotension were studied in patients with AOSC. The results showed that the plasma TXB2, 6-keto-PGF1 alpha and 6-keto-PGF1 alpha/TXB... |
2379216 | Distribution of substituents in 2-hydroxypropyl ethers of cyclomaltoheptaose. | The distribution of substituents in 2-hydroxypropyl ethers of cyclomaltoheptaose, prepared by alkylation of the carbohydrate with propylene oxide in aqueous sodium hydroxide, was investigated. The samples were fully methylated and hydrolyzed, and the resulting mixture of alkylated sugars analyzed as their alditol aceta... |
2361063 | 27 amino acid residues can be deleted from the N-terminus of human lymphotoxin without impairment of its cytotoxic activity. | In order to study the relationship between activity and structure of human lymphotoxin (hLT, 171 aa), we synthesized the gene (519 bp) for hLT and expressed it in Escherichia coli. Purification of the recombinant hLT from crude extracts was difficult because of the low level of expression of the gene. To improve the yi... |
2361062 | Effects of monomethoxypoly(ethylene glycol) modification of ribonuclease on antibody recognition, substrate accessibility and conformational stability. | The effects of modification of bovine pancreatic ribonuclease A by monomethoxypoly(ethylene glycol) (MPEG) were examined for changes in recognition by antiRNase antibodies, enzymatic activity against low and high molecular weight substrates and conformational stability to temperature elevation. Modified forms of RNase ... |
2361061 | Rabies virus binding to an acetylcholine receptor alpha-subunit peptide. | The binding of 125I-labeled rabies virus to a synthetic peptide comprising residues 173-204 of the alpha 1-subunit of the nicotinic acetylcholine receptor was investigated. Binding of rabies virus to the receptor peptide was dependent on pH, could be competed with by unlabeled homologous virus particles, and was satura... |
1694448 | Recognition of the acetylcholine receptor binding site of a long-chain neurotoxin by toxin-specific monoclonal antibodies. | The present paper reports the preparation and characterization of two neutralizing monoclonal antibodies (Mabs), called MST1 and MST2, which bind at the central loop of a long-chain neurotoxin from cobra venom. The central loop is a critical region for the binding of the toxin to the nicotinic acetylcholine receptor. S... |
1694447 | Prediction of the secondary structure and functional sites of major histocompatibility complex molecules. | A method for the theoretical prediction of the antigenic determinants and the antigen-interactive receptor sites of immunological proteins from their primary structure would constitute a useful tool for their study. Such a method developed in this laboratory uses hydrophilicity, accessibility, flexibility, and recognit... |
2163268 | Conformational constraints: nonpeptide beta-turn mimics. | The beta-turn, which has also been referred to as the beta-bend, beta-loop or reverse turn, has been implicated as an important site for molecular recognition in many biologically active peptides and in globular proteins. This small secondary structure therefore makes an attractive target for mimicry by a conformationa... |
2113569 | Radial component of CNS myelin: junctional subunit structure and supramolecular assembly. | The radial component is a structural specialization within CNS myelin that is believed to stabilize the apposition of membranes in the internode. Previous observations on thin sections and freeze-fracture replicas show that this junctional complex consists of linear, particulate strands that run parallel to the nerve f... |
2190210 | Flagellin as an object for supramolecular engineering. | A model of tertiary and quaternary structure of E. coli flagellin is suggested. According to this model, the molecule consists of two independent parts. One of them is formed by the N- and C-terminal regions of the polypeptide chain and is responsible for polymerization properties. The other consists of the central reg... |
2140594 | An antibody directed against a peptide encoded by RNA complementary to mRNA for vasopressin recognizes putative vasopressin receptors. | The purpose of this study was to generate an antibody against the binding site of the vasopressin receptor. Recently it has been demonstrated that complementary RNA sequences may encode interacting peptides. We determined whether or not an antibody directed against a peptide (PVA) specified by RNA complementary to the ... |
2188658 | Crystallographic studies of carbohydrates. | The monosaccharides which constitute the monomer units of many important industrial and biological macromolecules are well represented among the 2000 crystal structures of the carbohydrate class 45 of the Cambridge Structural Database. There are few examples of crystal structure analyses of the corresponding acids, but... |
2187592 | Immunoserology of infectious diseases. | The immune response to microorganisms not only participates in the elimination of unwanted organisms from the body, but also assists in diagnosis of infectious diseases. The nonspecific immune response is the first line of defense, assisting the body until the specific immune response can be mobilized to provide protec... |
1970441 | A bacterial enhancer functions to tether a transcriptional activator near a promoter. | The nitrogen regulatory protein NtrC of enteric bacteria activates transcription of the glnA gene by catalyzing isomerization of closed complexes between RNA polymerase and the glnA promoter to open complexes. NtrC binds to sites upstream of glnA that have properties of eukaryotic transcriptional enhancers. NtrC-bindin... |
2330033 | Relaxation of a transfer RNA specificity by removal of modified nucleotides. | The molecular recognition of specific transfer RNAs by the appropriate aminoacyl-tRNA synthetase is an important step in determining the accuracy of translation of the genetic message from nucleic acids into proteins. Recent studies using variant tRNAs with specific sequence modifications have indicated particular regi... |
1691636 | A fluorescent residualizing label for studies on protein uptake and catabolism in vivo and in vitro. | Residualizing labels are tracers which remain in lysosomes after uptake and catabolism of the carrier protein and have been especially useful for studies on the sites of plasma protein degradation. Thus far these labels have contained radioactive reporters such as 3H or 125I. In the present paper we describe a fluoresc... |
2326259 | Multiple sites of action of volatile anesthetics in Caenorhabditis elegans. | The mechanism and site(s) of action of volatile anesthetics are unknown. In all organisms studied, volatile anesthetics adhere to the Meyer-Overton relationship--that is, a ln-ln plot of the oil-gas partition coefficients versus the potencies yields a straight line with a slope of -1. This relationship has led to two c... |
2139098 | Strong T cell tolerance in parent----F1 bone marrow chimeras prepared with supralethal irradiation. Evidence for clonal deletion and anergy. | T cell tolerance induction was examined in long-term H-2-heterozygous parent----F1 chimeras prepared with supralethal irradiation (1,300 rad). Although these chimeras appeared to be devoid of host-type APC, the donor T cells developing in the chimeras showed marked tolerance to host-type H-2 determinants. Tolerance to ... |
2324201 | Correlation between structure and mass distribution of the nuclear pore complex and of distinct pore complex components. | Nuclear pore complexes (NPCs) prepared from Xenopus laevis oocyte nuclear envelopes were studied in "intact" form (i.e., unexposed to detergent) and after detergent treatment by a combination of conventional transmission electron microscopy (CTEM) and quantitative scanning transmission electron microscopy (STEM). In co... |
2182653 | An instructive role for the interstitial matrix in tissue patterning: tissue segregation and intercellular invasion. | Intercellular invasion is the intrusion of the cells of one tissue into space occupied by a second tissue. The alternative situation to invasion, one characteristic of most coherent tissues, is segregation, with identifiable boundaries existing between contiguous tissues. The interfaces between mesenchymal and myocardi... |
2182652 | Expression of extracellular matrix components is regulated by substratum. | Reconstituted basement membranes and extracellular matrices have been demonstrated to affect, positively and dramatically, the production of milk proteins in cultured mammary epithelial cells. Here we show that both the expression and the deposition of extracellular matrix components themselves are regulated by substra... |
2108969 | Cytoskeletal control of centrioles movement during the establishment of polarity in Madin-Darby canine kidney cells. | The two centrioles that are localized close to each other and to the nucleus in single Madin-Darby Canine kidney cells (MDCK) move apart by distances as large as 13 microns after the establishment of extensive cellular junctions. Microfilaments, and possibly microtubules appear to be responsible for this separation. In... |
2323341 | Nucleosome assembly in vitro: separate histone transfer and synergistic interaction of native histone complexes purified from nuclei of Xenopus laevis oocytes. | High speed supernatants of Xenopus laevis oocyte nuclei efficiently assemble DNA into nucleosomes in vitro under physiological salt conditions. The assembly activity cofractionates with two histone complexes composed of the acidic protein N1/N2 in complex with histones H3 and H4, and nucleoplasmin in complex with histo... |
2323336 | Inactivation of the HIV LTR by DNA CpG methylation: evidence for a role in latency. | Infection of cells by HIV can result in a period of quiescence or latency which may be obviated by treatment with inducing agents such as 5-azacytidine. Evidence from these experiments demonstrate the existence of two CpG sites in the HIV LTR which can silence transcription of both reporter genes (CAT) and infectious p... |
2321332 | Content and distribution of vasoactive intestinal polypeptide (VIP) in cavernous tissue of human penis. | Penile erection is controlled by a valvular structure in the helicine artery in humans. The opening and closing of this valve are believed to be regulated by the autonomic nervous system, especially through the release of vasoactive intestinal polypeptide (VIP). We determined the content of VIP in cavernous tissue in 1... |
2320575 | Immunological properties of hepatitis B core antigen fusion proteins. | The immunogenicity of a 19 amino acid peptide from foot-and-mouth disease virus has previously been shown to approach that of the inactivated virus from which it was derived after multimeric particulate presentation as an N-terminal fusion with hepatitis B core antigen. In this report we demonstrate that rhinovirus pep... |
2181437 | Regulation of icosahedral virion capsid size by the in vivo activity of a cloned gene product. | Determination of icosahedral virion capsid size can be directly studied during helper-dependent lytic development of satellite P4 because the assembly pathway specified by the P2 helper virus is altered to yield smaller-sized capsids. Size determination (sid) mutations identify a P4-encoded function regulating this pro... |
1690848 | A bacterial amber suppressor in Saccharomyces cerevisiae is selectively recognized by a bacterial aminoacyl-tRNA synthetase. | Little is known about the conservation of determinants for the identities of tRNAs between organisms. We showed previously that Escherichia coli tyrosine tRNA synthetase can charge the Saccharomyces cerevisiae mitochondrial tyrosine tRNA in vivo, even though there are substantial sequence differences between the yeast ... |
2156851 | Geometric arrangements of Tn3 resolvase sites. | Site-specific recombination by Tn3 resolvase normally occurs in vitro and in vivo only between directly repeated res sites on the same supercoiled DNA molecule. However, with multiply interlinked catenane substrates consisting of two DNA rings each containing a single res site, resolvase efficiently carried out intermo... |
2156825 | Amplified expression of tumor necrosis factor receptor in cells transfected with Epstein-Barr virus shuttle vector cDNA libraries. | As an approach to isolate the cell-surface receptor for tumor necrosis factor (TNF), we have developed transfectants of human B-lymphoblastoid cells (UC cells) that overexpress the TNF receptor. These transfectants were isolated from UC cells transfected with cDNA libraries of HeLa or NG108 cells constructed in the mam... |
1969394 | Characteristics of binding of Escherichia coli serotype O157:H7 strain CL-49 to purified intestinal mucin. | Purified rat intestinal mucin was used as a model mucin to study the binding of Escherichia coli serotype O157:H7, a human pathogen associated with outbreaks of hemorrhagic colitis and hemolytic uremic syndrome. Of six O157:H7 strains, only one strain (designated CL-49) bound to rat (and other) intestinal mucins by a s... |
2317524 | Acylglycerol reactivity and reaction mechanism of bovine milk lipoprotein lipase. | The sequential lipolysis of trioleoylglycerol and the triacylglycerols of very-low-density lipoprotein by bovine milk lipoprotein lipase can be described by the consecutive reactions: (formula: see text) where k'1, k'2 and k'3 are apparent first-order rate constants. The values of these rate constants dictate several c... |
21234016 | Barriers to prevention: physician perceptions of ideal versus actual practices in reducing cardiovascular risk. | We conducted a study to explore physician perceptions of factors that facilitate or inhibit the integration of preventive activities into primary care, particularly regarding the reduction of cardiovascular risk. Fifty randomly selected family physicians practising in the Maritimes were interviewed. Physicians describe... |
16348174 | Characterization of an endo-Acting Amylopullulanase from Thermoanaerobacter Strain B6A. | A thermoanaerobe (Thermoanaerobacter sp.) grown in TYE-starch (0.5%) medium at 60 degrees C produced both extra- and intracellular pullulanase (1.90 U/ml) and amylase (1.19 U/ml) activities. Both activities were produced at high levels on a variety of carbon sources. The temperature and pH optima for both pullulanase a... |
1966670 | Molecular recognition between oligopeptides and nucleic acids: DNA binding specificity of a series of bis netropsin analogues deduced from footprinting analysis. | A series of tether-linked bis netropsins have been synthesized in order to assess the phasing problem, which arises because of the lack of dimensional correspondence between oligopeptides and oligonucleotides in DNA binding characteristics. The consequences of incorporating variable-length flexible and rigid tethers [p... |
2095208 | Sequence-targeted photochemical modifications of nucleic acids by complementary oligonucleotides covalently linked to porphyrins. | Porphyrins linked to oligonucleotides produce various types of photodamage on a complementary target DNA. The observed reactions include oxidation of guanine bases and cross-linking reactions of the oligonucleotide to its target sequence. Guanines located close to the porphyrin macrocycle were the most altered as compa... |
2399741 | Antigen presentation by liposomes bearing class II MHC and membrane IL-1. | Liposomes containing membrane IL-1, Iak, and the antigen conalbumin were evaluated as "synthetic antigen presenting cells." The role of these three molecules in macrophage-T cell interaction was studied by testing their ability to induce the proliferation of a T-cell clone specific to conalbumin (the D10 cell line) or ... |
2144681 | Interleukin 1 receptors and biological responses. | Interleukin 1 (IL-1) is a polypeptide which possesses a wide variety of biological properties. IL-1 was originally studied as "endogenous pyrogen" and "leukocytic endogenous mediator" and more recently as "lymphocyte activating factor." Within a few minutes after intravenous injection into experimental animals, IL-1 tr... |
1368532 | Expression of the beta-cyclodextrin glucanotransferase gene of an alkalophilic Bacillus sp. #1011 in Escherichia coli cells and characterization of the synthesized enzyme. | To express efficiently the gene for extracellular beta-cyclodextrin glucanotransferase (beta-CGTase) of an alkalophilic Bacillus sp. #1011 using the E. coli promoters (tac, trp and PL promoters), three DNA fragments starting from the nucleotide positions +1, -18, and -48 of the translation initiation site of the gene w... |
2359313 | Considerations on the role of surface tension and epidermal growth factor in the mechanism of integumental pattern formation. | The formation of the posterior parietal hair whorl during normal human development is proposed as a morphogenetic problem in which the effects of surface tension and the appearance of singularities figure prominently. Surface tension is considered in the sense of "Langer's lines" which define local contours of tension ... |
2190812 | Cotinine analytical workshop report: consideration of analytical methods for determining cotinine in human body fluids as a measure of passive exposure to tobacco smoke. | A two-day technical workshop was convened November 10-11, 1986, to discuss analytical approaches for determining trace amounts of cotinine in human body fluids resulting from passive exposure to environmental tobacco smoke (ETS). The workshop, jointly sponsored by the U.S. Environmental Protection Agency and Centers fo... |
2348565 | [Changes in lymphocyte subsets, neutrophil function and complement levels in patients with complications following open heart surgery]. | In order to evaluate the immune response during and after open heart surgery, we have studied 34 patients who received open heart surgery under extracorporeal circulation. Age range of these patients were from 41 to 76 years. These patients were divided into three groups, depending upon existence of multiple organ fail... |
2347015 | Study of the interaction of clobazam with cyclodextrins in solution and in the solid state. | Inclusion complexes of clobazam with alpha-, beta-, gamma-cyclodextrins (CyDs) and heptakis(2.6-di-O-methyl)-beta-cyclodextrin (DM-beta-CyD) in aqueous solution and in the solid phase were studied by the solubility method, infrared (IR) spectroscopy, differential scanning calorimetry (DSC), and X-ray diffractometry. In... |
2338635 | Design and in vitro evaluation of slow-release dosage form of piretanide: utility of beta-cyclodextrin:cellulose derivative combination as a modified-release drug carrier. | To modify the release rate of piretanide, a potent loop diuretic, a double-layer tablet was designed, and in vitro release was evaluated. For a rapidly releasing portion, hydrophilic beta-cyclodextrin derivatives were employed to form a water-soluble complex with piretanide. For a sustained-release portion, cellulose d... |
2337603 | Structure of vancomycin and a vancomycin/D-Ala-D-Ala complex in solution. | Restrained molecular dynamics simulations were used to study the interactions between the glycopeptide antibiotic vancomycin and the dipeptide Ac-D-Ala-D-Ala. Restraints were obtained from a combination of homonuclear and heteronuclear two-dimensional NMR experiments (NOESY, ROESY, 1H-15N inverse correlation). The comp... |
2327958 | The supramolecular organization of ovomucin. Biophysical and morphological studies. | Ovomucin participates in the ovomucin-gel-forming properties because of its shape and its ability to interact in a specific spatial organization. Purified from chicken egg-white by exclusion chromatography with Sephacryl S-300 and Sepharose CL-2B and analysed by light-scattering, it exhibited an Mr of about 40 x 10(6).... |
2327954 | Dependence of the P2-S2 stereochemical selectivity of papain on the nature of the catalytic-site chemistry. Quantification of selectivity in the catalysed hydrolysis of the enantiomeric N-acetylphenylalanylglycine 4-nitroanilides. | 1. N-Acetyl-L-phenylalanylglycine 4-nitroanilide and its D-enantiomer were synthesized and characterized and used as substrates with which to evaluate stereochemical selectivity in papain (EC 3.4.22.2)-catalysed hydrolysis. 2. Kinetic analysis at pH 6.0, I 0.1, 8.3% (v/v) NN-dimethylformamide and 25 degrees C by using ... |
2181258 | Nucleotide excision repair in Escherichia coli. | One of the best-studied DNA repair pathways is nucleotide excision repair, a process consisting of DNA damage recognition, incision, excision, repair resynthesis, and DNA ligation. Escherichia coli has served as a model organism for the study of this process. Recently, many of the proteins that mediate E. coli nucleoti... |
2156860 | Interaction of a K(+)-competitive inhibitor, a substituted imidazo[1,2a] pyridine, with the phospho- and dephosphoenzyme forms of H+, K(+)-ATPase. | Defining the structural and catalytic properties of the ion transport site(s) of enzyme-phosphorylating ATPases is of key importance in understanding the mechanism of ion transport by these enzymes. In the case of the H+, K(+)-ATPase, SCH 28080 (3-(cyanomethyl)-2-methyl-8-(phenylmethoxy)imidazo[1,2a]-pyridine) has been... |
1969331 | Topographical relationships between catecholamine- and neuropeptide-containing fibers in the median eminence of the newt, Triturus alpestris. An ultrastructural immunocytochemical study. | Dopaminergic and peptidergic nerve fibers were simultaneously demonstrated with a double-labeling technique at the ultrastructural level. The first antibody, raised against tyrosine hydroxylase, was applied during the preembedding phase and visualized with the peroxidase method. The second antibody, raised against one ... |
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