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9691303 | Method for the separation of the unconjugates and conjugates of chenodeoxycholic acid and deoxycholic acid by two-dimensional reversed-phase thin layer chromatography with methyl beta-cyclodextrin. | A simple and efficient method for the separation of individual unconjugated bile acids and their glycine- and taurine-amidated, 3-sulfated, 3-glucosylated and 3-glucuronidated conjugates is described. The method involves the use of a two-dimensional (2D) reversed-phase (RP) high-performance thin-layer chromatographic (... |
9688524 | Structural analysis of the amplified IFN-beta and DHFR genes in a Chinese hamster ovary cell line using multicolour FISH analysis. | Multicolour FISH was used to get insight into the structural arrangement of a homogeneously staining region which bears the co-transfected and subsequently co-amplified IFN-beta and DHFR genes in a CHO cell line. On metaphase chromosomes an arrangement of multiple bands with regular spacing is revealed. On extended chr... |
9688523 | Specific chromomeres on the chicken W lampbrush chromosome contain specific repetitive DNA sequence families. | Chromomeres 1 and 3 of the chicken W lampbrush chromosome contain most of the EcoRI and XhoI repeat sequence families respectively. These chromomeres were stained with DAPI and their sizes relative to other W chromomeres were observed. Their relative contents of EcoRI and XhoI repeats were determined using fluorescence... |
9688522 | Terminal heterochromatin and alternative telomeric sequences in Allium cepa. | The chromosome termini of the onion (Allium cepa) apparently lack Arabidopsis-type telomeric repeats. The terminal Giemsa bands of A. cepa chromosomes contain a 375-bp satellite and (short arm of chromosome 8)/ or (short arm of chromosome 6) rDNA repeats. By means of fluorescence in situ hybridization (FISH) on metapha... |
9688521 | Identification of 16 chicken microchromosomes by molecular markers using two-colour fluorescence in situ hybridization (FISH). | A feature of avian karyotypes is the presence of microchromosomes. As a typical avian genome, the chicken karyotype (2n = 78) consists of nine pairs of macrochromosomes, including the W and Z sexual chromosomes, and 30 pairs of indistinguishable microchromosomes usually ordered arbitrarily by decreasing size. Despite t... |
9688520 | Localization of the repetitive telomeric sequence (TTAGGG)n in four sturgeon species. | We analysed the localization of the telomeric sequence (TTAGGG)n in four species of the genus Acipenser, namely A. naccarii (2n = 246 +/- 6), A. ruthenus (2n = 118 +/- 4), A. gueldenstaedti (2n = 256 +/- 6) and A. baeri (2n = 246 +/- 8). The hybridization signal was localized at the telomeres of all chromosomes in A. n... |
9688519 | A novel repetitive sequence of sugar cane, SCEN family, locating on centromeric regions. | Tandem repetitive sequences consisting of 140-bp repetitive units were cloned from sugar cane genomic DNA and designated the SCEN family. In situ hybridization revealed that they were located on the centromeric region of almost all of the chromosomes of sugar cane. The 140-bp sequence included three CENP-B box-like seq... |
9688518 | Pachytene chromosomes in trisomy 19 male mice with Robertsonian translocations. | Three male mice with trisomy 19 induced by a Robertsonian translocation system were used for the study of meiotic prophase cells and germ cell differentiation. Present in these males were two Robertsonian chromosomes each with a chromosome 19 arm in common, two acrocentric chromosomes corresponding to the second arms o... |
9688517 | Meiotin-1, a meiosis-enriched protein present in normal leptotene chromosomes and lacking in precociously condensed leptotene chromosomes. | During mitotic prophase, chromosomes progressively compact to their metaphase length. In contrast, meiotic chromosomes condense moderately until late in prophase I, then they condense more dramatically (coil) to their fully condensed state. Meiotin-1 is a meiosis-enriched, chromosomal protein. We propose that it delays... |
9688516 | Analysis of meiotic chromosome pairing in the female mouse using a novel minichromosome. | Analysis of a radiation-induced minichromosome using classical cytogenetic techniques and fluorescence in situ hybridization (FISH) has shown this element to be composed primarily, if not entirely, of repeat sequence DNAs that are common to the ends of all chromosomes in the mouse genome. This novel chromosome has been... |
9688515 | Origin of human chromosome 21 and its consequences: a 50-million-year-old story. | Great apes (Pongidae) possess a chromosome similar to human chromosome 21 (HSA21), whose trisomy was described in both chimpanzee and orangutan. Having studied more than 200 mammalian species by chromosome banding techniques and reconstructed Primates phylogeny, we reinvestigated, using fluorescence in situ hybridizati... |
9688514 | Cytogenetic studies in some species of Scorpaeniformes (Teleostei: Percomorpha). | Cytogenetic studies were performed in four species of two scorpaeniform teleost families: Scorpaenidae and Triglidae. The karyotypes of Trigla lucerna, Trigloporus lastoviza (Triglidae), Scorpaena porcus and S. notata (Scorpaenidae) were analysed using various banding methods and in situ hybridization with a telomeric ... |
9688513 | A new derived and highly polymorphic chromosomal race of Liolaemus monticola (Iguanidae) from the 'Norte Chico' of Chile. | A multiple Robertsonian fission chromosomal race of the Liolaemus monticola complex in Chile is described and is shown to be the most derived and the most complex among the Liolaemus examined thus far. The 29 karyotyped lizards analysed from the locality of Mina Hierro Viejo, Petorca, Provincia de Valparaiso, Chile, ex... |
9688354 | Oral aluminum administration to rats wih normal renal function. 1. Impairment of erythropoiesis. | Aluminum (Al) toxicity has been mainly investigated in uremic patients although healthy subjects and patients without renal insufficiency are not exempt from its potential deleterious effects. This experimental study aims to elucidate the action of different doses of Al citrate on in vivo erythropoiesis and find out wh... |
9688256 | Cobatoxins 1 and 2 from Centruroides noxius Hoffmann constitute a subfamily of potassium-channel-blocking scorpion toxins. | Potassium-channel-blocking scorpion toxins (alpha-K-toxins) have been shown to be valuable tools for the study of potassium channels. Here we report two toxins, cobatoxin 1 and 2, of 32 amino acids, containing three disulphide bridges, that were isolated from the venom of the Mexican scorpion Centruroides noxius. Their... |
9688224 | Aqueous hydrocortisone mouthwash solution: clinical evaluation. | Patients often experience difficulties in applying topical steroids in orabase to the oral mucosa, particularly when large areas need to be covered. An aqueous hydrocortisone mouthwash solution has been developed, one that was anticipated to be more acceptable to patients. The solution contains hydrocortisone (0.3% w/v... |
9687264 | Triplet photochemistry of suprofen in aqueous environment and in the beta-cyclodextrin inclusion complex. | The photodecarboxylation of suprofen in the carboxylate form was studied in aqueous medium as a function of the temperature, the concentration and the presence of oxygen by steady-state and time-resolved photochemical techniques. The process is characterized by an activation energy of 9-10 kcal/mol, the precursor state... |
9681781 | Multiple organ failure (MOF) after severe trauma--a sheep model. | <h4>Objective</h4>To perform a reproducible long-term (10 days) large animal model of multiple systems organ failure without necessity of a continuous stimulus.<h4>Design</h4>Adult female merino sheep submitted to a 5-day stimulation period followed by a 5-day observation period. Day 1: Hemorrhagic shock was combined w... |
9680073 | Transdermal iontophoretic delivery of hydrocortisone from cyclodextrin solutions. | Enhanced skin penetration of hydrocortisone can be desirable for treatment of several diseases. Transdermal iontophoretic delivery of hydrocortisone solubilized in an aqueous solution of hydroxypropyl-beta-cyclodextrin (HP-beta-CyD) was investigated and compared with chemical enhancement of co-solvent formulations. The... |
9680070 | Water-soluble beta-cyclodextrins in paediatric oral solutions of spironolactone: preclinical evaluation of spironolactone bioavailability from solutions of beta-cyclodextrin derivatives in rats. | Water-soluble derivatives of beta-cyclodextrin have been considered for solubilization of spironolactone in the formulation of a safe liquid preparation for premature infants. The oral absorption of spironolactone was studied in rats to evaluate the need to adjust spironolactone dosage in prospective clinical studies. ... |
9676579 | Ultrastructural localization of microfibrillar fibulin-1 and fibulin-2 during heart development indicates a switch in molecular associations. | The microfibrillar proteins fibulin-1 and fibulin-2 were previously identified as prominent components of the endocardial cushion tissue (ECT) during heart development and shown to persist in adult valves and septa. Immunogold staining has now been used to compare their localization in embryonic (days 9-11) and adult m... |
9669043 | Reduction of the suppressive effects of gurmarin on sweet taste responses by addition of beta-cyclodextrin. | Cyclodextrins (CDs) have the remarkable ability to form inclusion complexes with a wide variety of guest molecules. In the present study, possible influences of CDs on gurmarin inhibition of the chorda tympani responses to sucrose were examined in C57BL mice. Responses to sucrose were suppressed to approximately 50% of... |
9669658 | Interaction of oligodeoxynucleotides with mycobacteria: implications for new therapeutic strategies. | The use of synthetic oligonucleotides (ONs) to systematically address new pharmacologic targets in mycobacteria would enhance the introduction of new molecular targets for drug intervention. Oligonucleotides' mechanism of action allows researchers to pursue the importance of particular proteins without the requirement ... |
9669330 | GATC motifs may alter the conformation of DNA depending on sequence context and N6-adenine methylation status: possible implications for DNA-protein recognition. | As part of our analysis of the role of a uniquely clustered set of dam methylation sites (the motif GATC) within the origin of DNA replication in Escherichia coli, we have studied the effect of GATCs in various methylation states on the intrinsic curvature of DNA. We have designed a set of DNA linkers and used commerci... |
9667645 | Modulation of P450-dependent ifosfamide pharmacokinetics: a better understanding of drug activation in vivo. | The anti-cancer prodrug ifosfamide (IF) is metabolized by liver P450 enzymes by two alternative pathways. IF is activated to 4-hydroxy IF (4-OH-IF), which ultimately yields the alkylating mustard isophosphoramide, whereas IF N-dechlororethylation inactivates the drug and produces the neurotoxic metabolite chloroacetald... |
9663696 | Mitochondrial swelling and oxygen consumption during respiratory state 4 induced by phospholipase A2 isoforms isolated from the South American rattlesnake (Crotalus durissus terrificus) venom. | The non-covalent interaction between two molecular entities namely, phospholipase A2 and crotapotin, results in the main toxin, crotoxin, present in the venom of the South American rattlesnake Crotalus durissus terrificus. High performance liquid chromatography has enabled us the isolation of three phospholipase A2 iso... |
9662453 | Site directed mutants of Noxiustoxin reveal specific interactions with potassium channels. | Several site directed mutations were introduced into a synthetic Noxiustoxin (NTX) gene. Alanine scanning of the nonapeptide at the N-terminal segment of NTX (threonine 1 (T1) to serine 9 (S9)) was constructed and the recombinant products were obtained in pure form. Additionally, lysine 28 (K28) was changed to arginine... |
9662168 | Enantiomeric separation of methadone by cyclodextrin-based capillary and recycling isotachophoresis. | The separation of methadone enantiomers by cationic capillary isotachophoresis (CITP) and recycling isotachophoresis (RITP) having (2-hydroxypropyl)-beta-cyclodextrin (OHP-beta-CD) as chiral selector in the leading electrolyte is described. Sodium acetate/acetic acid (pH between 4 and 5) served as leading electrolyte (... |
9655513 | The location of the gate in the acetylcholine receptor channel. | The cation-conducting channel of the nicotinic acetylcholine (ACh) receptor is lined by the first (M1) and second (M2) membrane-spanning segments of each of its five subunits. Six consecutive residues, alphaS239 to alphaT244, in the alpha subunit M1-M2 loop and at the intracellular end of M2 were mutated to cysteine. T... |
9653551 | 19F NMR in the measurement of binding affinities of chloroeremomycin to model bacterial cell-wall surfaces that mimic VanA and VanB resistance. | <h4>Background</h4>The emergence of bacteria that are resistant to vancomycin, the drug of choice against methicillin-resistant Staphylococcus aureus, has made the study of the binding characteristics of glycopeptides to biologically relevant depsipeptides important. These depsipeptides, terminating in D-alanyl-D-lacta... |
9649333 | Nonesterified fatty acids induce transmembrane monovalent cation flux: host-guest interactions as determinants of fatty acid-induced ion transport. | Nonesterified fatty acids are key intermediates in cellular metabolism whose intracellular concentration is regulated by multiple anabolic, catabolic, and oxidative enzymatic cascades. Herein, we demonstrate that fatty acids induce transmembrane monovalent cation flux with an apparent rate constant kapp = 10(-)4 - 10(-... |
9650577 | Activation of the A2A adenosine receptor inhibits nitric oxide production in glial cells. | Selective adenosine receptor agonists and antagonists have marked effects on the outcome of cerebral ischemia, and adenosine receptors are expressed on astrocytes. In this study we examined the effects of various adenosine receptor agonists on the production of nitric oxide and the induction of iNOS in astrocytes activ... |
9647652 | Activity-dependent regulation of dendritic BC1 RNA in hippocampal neurons in culture. | Several neuronal RNAs have been identified in dendrites, and it has been suggested that the dendritic location of these RNAs may be relevant to the spatiotemporal regulation of mosaic postsynaptic protein repertoires through transsynaptic activity. Such regulation would require that dendritic RNAs themselves, or at lea... |
9647643 | Localization, dynamics, and protein interactions reveal distinct roles for ER and Golgi SNAREs. | ER-to-Golgi transport, and perhaps intraGolgi transport involves a set of interacting soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins including syntaxin 5, GOS-28, membrin, rsec22b, and rbet1. By immunoelectron microscopy we find that rsec22b and rbet1 are enriched in COPII-coated... |
9642139 | Artificial imitation of glutathione peroxidase with 6-selenium-bridged beta-cyclodextrin. | On the basis of cyclodextrin, 6-selenium bridged beta-cyclodextrin (6-beta-CD-Se-Se-beta-CD, known as 6-SeCD) was synthesized by the selective tosylation of beta-cyclodextrin and nucleophilic displacement by sodium hydroselenide to imitate glutathione peroxidase (GPX). The GPX activity of diselenide 6-SeCD is 4.3 times... |
9642073 | Ecotin: a serine protease inhibitor with two distinct and interacting binding sites. | The interaction between ecotin and target proteases with trypsin-like specificity has been systematically dissected to understand the structural basis of ecotin's broad inhibitory specificity and the role of the secondary binding site. Site-directed and region-specific mutagenesis were preformed at ecotin's primary sit... |
9636163 | Structural basis of an embryonically lethal single Ala --> Thr mutation in the vnd/NK-2 homeodomain. | The structural and DNA binding behavior is described for an analog of the vnd/NK-2 homeodomain, which contains a single amino acid residue alanine to threonine replacement in position 35 of the homeodomain. Multidimensional nuclear magnetic resonance, circular dichroism, and electrophoretic gel retardation assays were ... |
9636161 | Antigen binding forces of individually addressed single-chain Fv antibody molecules. | Antibody single-chain Fv fragment (scFv) molecules that are specific for fluorescein have been engineered with a C-terminal cysteine for a directed immobilization on a flat gold surface. Individual scFv molecules can be identified by atomic force microscopy. For selected molecules the antigen binding forces are then de... |
9636143 | Supramolecular organization of immature and mature murine leukemia virus revealed by electron cryo-microscopy: implications for retroviral assembly mechanisms. | We have used electron cryo-microscopy and image analysis to examine the native structure of immature, protease-deficient (PR-) and mature, wild-type (WT) Moloney murine leukemia virus (MuLV). Maturational cleavage of the Gag polyprotein by the viral protease is associated with striking morphological changes. The PR- Mu... |
9636141 | A synthetic all D-amino acid peptide corresponding to the N-terminal sequence of HIV-1 gp41 recognizes the wild-type fusion peptide in the membrane and inhibits HIV-1 envelope glycoprotein-mediated cell fusion. | Recent studies demonstrated that a synthetic fusion peptide of HIV-1 self-associates in phospholipid membranes and inhibits HIV-1 envelope glycoprotein-mediated cell fusion, presumably by interacting with the N-terminal domain of gp41 and forming inactive heteroaggregates [Kliger, Y., Aharoni, A., Rapaport, D., Jones, ... |
9636133 | A coupled proton-transfer and twisting-motion fluorescence probe for lipid bilayers. | A new and sensitive molecular probe, 2-(2'-hydroxyphenyl)imidazo[1, 2-a]pyridine (HPIP), for monitoring structural changes in lipid bilayers is presented. Migration of HPIP from water into vesicles involves rupture of hydrogen (H) bonds with water and formation of an internal H bond once the probe is inside the vesicle... |
9636067 | Strong selective pressure to use G:U to mark an RNA acceptor stem for alanine. | The identity of alanine tRNAs is dependent on a G:U base pair at the 3:70 position of the acceptor helix. This system of molecular recognition is widely distributed from bacteria to human-cell cytoplasm. In contrast, some mitochondrial alanine acceptor helices are markedly different and contain nucleotides known to blo... |
9636048 | Aspartate 221 of thymidylate synthase is involved in folate cofactor binding and in catalysis. | Structural studies indicate that Asp 221 of Lactobacilluscasei thymidylate synthase forms a hydrogen bond network with the 2-amino and 3-imino groups of the folate [Matthews, D. A. (1990) J. Mol. Biol. 214, 937-948; Finer-Moore, J. S. (1990)Biochemistry 29, 6977-6986] that has been proposed to participate in catalysis.... |
9639356 | Initial analysis of the molecular image of pamlin, a sea urchin cell adhesion protein, by transmission electron microscopy. | Pamlin, an important extracellular protein required early for sea urchin embryogenesis, is readily isolated from the embryos of Hemicentrotus pulcherrimus. A molecular image analysis of pamlin was conducted using immuno-electron microscopy, rotary shadowing and negative staining technique-applied electron microscopy. T... |
9637161 | Recombinant human granulocyte colony-stimulating factor attenuates inflammatory responses in septic patients with neutropenia. | <h4>Objective</h4>The objective of this study was to determine the effects of recombinant human granulocyte colony-stimulating factor (rhG-CSF) administration in septic patients with neutropenia.<h4>Methods</h4>Twenty consecutive septic patients were administered rhG-CSF subcutaneously (2 microg x kg(-1) x d(-1)) for 5... |
9637159 | Intestinal permeability correlates with severity of injury in trauma patients. | <h4>Background</h4>Increased intestinal permeability (IP) and the release of toxic intraluminal materials have been implicated in the systemic inflammatory response syndrome (SIRS) and multiple organ failure (MOF) observed in patients after severe trauma. Previous studies of intestinal permeability have failed to demon... |
9635777 | Fatty acid-induced alteration of the porphyrin macrocycle of cytochrome P450 BM3. | Surface-enhanced resonance Raman scattering (SERRS) of substrate-free and substrate-bound forms of the P450 domain of cytochrome P450 BM3 are reported and assigned. Substrate-free P450 yields mixed spin heme species in which the pentacoordinate high-spin arrangement is dominant. The addition of laurate or palmitate lea... |
9635774 | Fibrous long spacing collagen ultrastructure elucidated by atomic force microscopy. | Fibrous long spacing collagen (FLS) fibrils are collagen fibrils in which the periodicity is clearly greater than the 67-nm periodicity of native collagen. FLS fibrils were formed in vitro by the addition of alpha1-acid glycoprotein to an acidified solution of monomeric collagen and were imaged with atomic force micros... |
9635755 | Intensive extrusion and occlusion of water in ganglioside micelles with thermal reversibility. | By using a shell-modeling analysis for small-angle scattering data of ganglioside micellar dispersion, we recently reported that the elevation of temperature induces a significant shrinkage of the hydrophilic region of the ganglioside micelle, suggesting that the oligosaccharide chains with sialic acid residues of gang... |
9635752 | Phase transitions in films of lung surfactant at the air-water interface. | Pulmonary surfactant maintains a putative surface-active film at the air-alveolar fluid interface and prevents lung collapse at low volumes. Porcine lung surfactant extracts (LSE) were studied in spread and adsorbed films at 23 +/- 1 degrees C using epifluorescence microscopy combined with surface balance techniques. B... |
9635735 | Geometry and physics of catenanes applied to the study of DNA replication. | The concept of ideal geometric configurations was recently applied to the classification and characterization of various knots. Different knots in their ideal form (i.e., the one requiring the shortest length of a constant-diameter tube to form a given knot) were shown to have an overall compactness proportional to the... |
9635731 | Low-resolution structures of proteins in solution retrieved from X-ray scattering with a genetic algorithm. | Small-angle x-ray solution scattering (SAXS) is analyzed with a new method to retrieve convergent model structures that fit the scattering profiles. An arbitrary hexagonal packing of several hundred beads containing the problem object is defined. Instead of attempting to compute the Debye formula for all of the possibl... |
9632352 | A pyridoxine cyclic phosphate and its 6-azoaryl derivative selectively potentiate and antagonize activation of P2X1 receptors. | Analogues of the P2 receptor antagonists pyridoxal-5'-phosphate and the 6-azophenyl-2',4'-disulfonate derivative (PPADS), in which the phosphate group was cyclized by esterification to a CH2OH group at the 4-position, were synthesized. The cyclic pyridoxine-alpha4, 5-monophosphate, compound 2 (MRS 2219), was found to b... |
9620954 | The Caulobacter crescentus paracrystalline S-layer protein is secreted by an ABC transporter (type I) secretion apparatus. | Caulobacter crescentus is a gram-negative bacterium that produces a two-dimensional crystalline array on its surface composed of a single 98-kDa protein, RsaA. Secretion of RsaA to the cell surface relies on an uncleaved C-terminal secretion signal. In this report, we identify two genes encoding components of the RsaA ... |
9628891 | A calcium signaling cascade essential for myosin thick filament assembly in Xenopus myocytes. | Spontaneous calcium release from intracellular stores occurs during myofibrillogenesis, the process of sarcomeric protein assembly in striated muscle. Preventing these Ca2+ transients disrupts sarcomere formation, but the signal transduction cascade has not been identified. Here we report that specific blockade of Ca2+... |
9624180 | Gbeta gamma-independent coupling of alpha2-adrenergic receptor to p21(rhoA) in preadipocytes. | In preadipocytes, alpha2-adrenergic receptor (alpha2-AR) stimulation leads to a Gi/Go-dependent rearrangement of actin cytoskeleton. This is characterized by a rapid cell spreading, the formation of actin stress fibers, and the increase in tyrosyl phosphorylation of the focal adhesion kinase (pp125(FAK)). These cellula... |
9624151 | Inhibition of the self-assembly of collagen I into fibrils with synthetic peptides. Demonstration that assembly is driven by specific binding sites on the monomers. | A series of experiments were carried out to test the hypothesis that the self-assembly of collagen I monomers into fibrils depends on the interactions of specific binding sites in different regions of the monomer. Six synthetic peptides were prepared with sequences found either in the collagen triple helix or in the N-... |
9624113 | The key step in chlorophyll breakdown in higher plants. Cleavage of pheophorbide a macrocycle by a monooxygenase. | Chlorophyll breakdown in green plants is a long-standing biological enigma. Recent work has shown that pheophorbide a (Pheide a) derived from chlorophyll (Chl) is converted oxygenolytically into a primary fluorescent catabolite (pFCC-1) via a red Chl catabolite (RCC) intermediate. RCC, the product of the ring cleavage ... |
9624485 | Novel antibiotic susceptibility tests by the ATP-bioluminescence method using filamentous cell treatment. | Antimicrobial susceptibility testing by the ATP-bioluminescence method has been noted for its speed; it provides susceptibility results within 2 to 5 h. However, several disagreements between the ATP method and standard methodology have been reported. The present paper describes a novel ATP method in a 3.5-h test which... |
9618448 | Replication and control of circular bacterial plasmids. | An essential feature of bacterial plasmids is their ability to replicate as autonomous genetic elements in a controlled way within the host. Therefore, they can be used to explore the mechanisms involved in DNA replication and to analyze the different strategies that couple DNA replication to other critical events in t... |
9618447 | Type III protein secretion systems in bacterial pathogens of animals and plants. | Various gram-negative animal and plant pathogens use a novel, sec-independent protein secretion system as a basic virulence mechanism. It is becoming increasingly clear that these so-called type III secretion systems inject (translocate) proteins into the cytosol of eukaryotic cells, where the translocated proteins fac... |
9618441 | Signalling in the yeasts: an informational cascade with links to the filamentous fungi. | All cells, from bacteria and yeasts to mammalian cells, respond to cues from their environment. A variety of mechanisms exist for the transduction of these external signals to the interior of the cell, resulting in altered patterns of protein activity. Eukaryotic cells commonly transduce external cues via a conserved m... |
9618558 | A release mechanism for stored ATP in ocular ciliary epithelial cells. | Purines can modify ciliary epithelial secretion of aqueous humor into the eye. The source of the purinergic agonists acting in the ciliary epithelium, as in many epithelial tissues, is unknown. We found that the fluorescent ATP marker quinacrine stained rabbit and bovine ciliary epithelia but not the nerve fibers in th... |
9618527 | A physiological role of the adenosine A3 receptor: sustained cardioprotection. | Adenosine released during cardiac ischemia exerts a potent, protective effect in the heart. A newly recognized adenosine receptor, the A3 subtype, is expressed on the cardiac ventricular cell, and its activation protects the ventricular heart cell against injury during a subsequent exposure to ischemia. A cultured chic... |
9618485 | Terpenoid-based defenses in conifers: cDNA cloning, characterization, and functional expression of wound-inducible (E)-alpha-bisabolene synthase from grand fir (Abies grandis). | (E)-alpha-Bisabolene synthase is one of two wound-inducible sesquiterpene synthases of grand fir (Abies grandis), and the olefin product of this cyclization reaction is considered to be the precursor in Abies species of todomatuic acid, juvabione, and related insect juvenile hormone mimics. A cDNA encoding (E)-alpha-bi... |
9618473 | The RIIbeta regulatory subunit of protein kinase A binds to cAMP response element: an alternative cAMP signaling pathway. | cAMP, through the activation of cAMP-dependent protein kinase (PKA), is involved in transcriptional regulation. In eukaryotic cells, cAMP is not considered to alter the binding affinity of CREB/ATF to cAMP-responsive element (CRE) but to induce serine phosphorylation and consequent increase in transcriptional activity.... |
9618462 | The design, computer modeling, solution structure, and biological evaluation of synthetic analogs of bryostatin 1. | The bryostatins are a unique family of emerging cancer chemotherapeutic candidates isolated from marine bryozoa. Although the biochemical basis for their therapeutic activity is not known, these macrolactones exhibit high affinities for protein kinase C (PKC) isozymes, compete for the phorbol ester binding site on PKC,... |
9622124 | The RNA sequence context defines the mechanistic routes by which yeast arginyl-tRNA synthetase charges tRNA. | Arginylation of tRNA transcripts by yeast arginyl-tRNA synthetase can be triggered by two alternate recognition sets in anticodon loops: C35 and U36 or G36 in tRNA(Arg) and C36 and G37 in tRNA(Asp) (Sissler M, Giegé R, Florentz C, 1996, EMBO J 15:5069-5076). Kinetic studies on tRNA variants were done to explore the mec... |
9616227 | Lack of strong immune selection pressure by the immunodominant, HLA-A*0201-restricted cytotoxic T lymphocyte response in chronic human immunodeficiency virus-1 infection. | Despite detailed analysis of the HIV-1-specific cytotoxic T lymphocyte response by various groups, its relation to viral load and viral sequence variation remains controversial. We analyzed HLA-A*0201 restricted cytotoxic T lymphocyte responses in 17 HIV-1-infected individuals with viral loads ranging from < 400 to 221... |
9614181 | RhoG GTPase controls a pathway that independently activates Rac1 and Cdc42Hs. | RhoG is a member of the Rho family of GTPases that shares 72% and 62% sequence identity with Rac1 and Cdc42Hs, respectively. We have expressed mutant RhoG proteins fused to the green fluorescent protein and analyzed subsequent changes in cell surface morphology and modifications of cytoskeletal structures. In rat and m... |
9611241 | Interaction between the N-terminal domain of human DNA topoisomerase I and the arginine-serine domain of its substrate determines phosphorylation of SF2/ASF splicing factor. | Human DNA topoisomerase I, known for its DNA-relaxing activity, is possibly one of the kinases phosphorylating members of the SR protein family of splicing factors, in vivo. Little is known about the mechanism of action of this novel kinase. Using the prototypical SR protein SF2/ASF (SRp30a) as model substrate, we demo... |
9611232 | TAR-RNA binding by HIV-1 Tat protein is selectively inhibited by its L-enantiomer. | An oligoribonucleotide, corresponding to the Tat-interactive top half of the HIV-1 TAR RNA stem-loop, was synthesized in both the natural D- and the enantiomeric L-configurations. The affinity of Tat for the two RNAs, assessed by competition binding experiments, was found to be identical and is reduced 10-fold for both... |
9611210 | Probable mechanisms underlying interallelic complementation and temperature-sensitivity of mutations at the shibire locus of Drosophila melanogaster. | The shibire locus of Drosophila melanogaster encodes dynamin, a GTPase required for the fission of endocytic vesicles from plasma membrane. Biochemical studies indicate that mammalian dynamin is part of a complex containing multiple dynamin subunits and other polypeptides. To gain insight into sequences of dynamin crit... |
9607948 | Colon-specific drug delivery based on a cyclodextrin prodrug: release behavior of biphenylylacetic acid from its cyclodextrin conjugates in rat intestinal tracts after oral administration. | An antiinflammatory drug biphenylylacetic acid (BPAA) as a model drug was selectively conjugated onto one of the primary hydroxyl groups of alpha-, beta-, and gamma-cyclodextrins (CyDs) through an ester or amide linkage, and the in vivo drug release behavior of these prodrugs in rat gastrointestinal tracts after oral a... |
9609688 | Contribution of the beta subunit M2 segment to the ion-conducting pathway of the acetylcholine receptor. | We have applied the substituted-cysteine-accessibility method (SCAM) to the M2 segment and the M1-M2 loop of the acetylcholine (ACh) receptor beta subunit. Each residue from beta P248 to beta D273 was mutated one at a time to Cys, and the mutant beta subunits were expressed together with wild-type alpha, beta, and delt... |
9607933 | State-dependent accessibility and electrostatic potential in the channel of the acetylcholine receptor. Inferences from rates of reaction of thiosulfonates with substituted cysteines in the M2 segment of the alpha subunit. | Ion channel function depends on the chemical and physical properties and spatial arrangement of the residues that line the channel lumen and on the electrostatic potential within the lumen. We have used small, sulfhydryl-specific thiosulfonate reagents, both positively charged and neutral, to probe the environment with... |
9606215 | Death-effector filaments: novel cytoplasmic structures that recruit caspases and trigger apoptosis. | The death-effector domain (DED) is a critical protein interaction domain that recruits caspases into complexes with members of the TNF-receptor superfamily. Apoptosis can also be induced by expressing certain DED-containing proteins without surface receptor cross-linking. Using Green Fluorescent Protein to examine DED-... |
9606210 | Localization of Mad2 to kinetochores depends on microtubule attachment, not tension. | A single unattached kinetochore can delay anaphase onset in mitotic tissue culture cells (Rieder, C.L., A. Schultz, R. Cole, G. Sluder. 1994. J. Cell Biol. 127:1301-1310). Kinetochores in vertebrate cells contain multiple binding sites, and tension is generated at kinetochores after attachment to the plus ends of spind... |
9606181 | The Vps4p AAA ATPase regulates membrane association of a Vps protein complex required for normal endosome function. | Vps4p is an AAA-type ATPase required for efficient transport of biosynthetic and endocytic cargo from an endosome to the lysosome-like vacuole of Saccharomyces cerevisiae. Vps4p mutants that do not bind ATP or are defective in ATP hydrolysis were characterized both in vivo and in vitro. The nucleotide-free or ADP-bound... |
9603877 | Activation and repression of transcription at the double tandem divergent promoters for the xylR and xylS genes of the TOL plasmid of Pseudomonas putida. | The xylR and xylS genes are divergent and control transcription of the TOL plasmid catabolic pathways for toluene metabolism. Four promoters are found in the 300-bp intergenic region: Pr1 and Pr2 are constitutive sigma70-dependent tandem promoters that drive expression of xylR, while expression of the xylS gene is driv... |
9603811 | Towards a biocatalyst for (S)-styrene oxide production: characterization of the styrene degradation pathway of Pseudomonas sp. strain VLB120. | In order to design a biocatalyst for the production of optically pure styrene oxide, an important building block in organic synthesis, the metabolic pathway and molecular biology of styrene degradation in Pseudomonas sp. strain VLB120 was investigated. A 5.7-kb XhoI fragment, which contained on the same strand of DNA s... |
9596703 | Stable transfection of Trypanosoma cruzi epimastigotes with the trypomastigote-specific complement regulatory protein cDNA confers complement resistance. | Trypanosoma cruzi blood stage trypomastigotes are highly resistant to complement-mediated killing in normal serum. A previously described trypomastigote surface glycoprotein was shown to have binding affinity for human complement components C3b and C4b and restrict activation of the complement cascade, thus preventing ... |
9596696 | Cytochalasin-induced actin disruption of polarized enterocytes can augment internalization of bacteria. | Cytochalasin-induced actin disruption has often been associated with decreased bacterial internalization by cultured epithelial cells, although polarized enterocytes have not been systematically studied. In assays using confluent polarized HT-29 enterocytes, cytochalasin D appeared to increase internalization of wild-t... |
9580562 | Spinalin, a new glycine- and histidine-rich protein in spines of Hydra nematocysts. | Here we present the cloning, expression and immunocytochemical localization of a novel 24 kDa protein, designated spinalin, which is present in the spines and operculum of Hydra nematocysts. Spinalin cDNA clones were identified by in situ hybridization to differentiating nematocytes. Sequencing of a full-length clone r... |
9573264 | Entry of amphotropic murine leukemia virus is influenced by residues in the putative second extracellular domain of its receptor, Pit2. | Human cells express distinct but related receptors for the gibbon ape leukemia virus (GALV) and the amphotropic murine leukemia virus (A-MuLV), termed Pit1 and Pit2, respectively. Pit1 is not able to function as a receptor for A-MuLV infection, while Pit2 does not confer susceptibility to GALV. Previous studies of chim... |
9573255 | High-efficiency gene transfer into normal and adenosine deaminase-deficient T lymphocytes is mediated by transduction on recombinant fibronectin fragments. | Primary human T lymphocytes are powerful targets for genetic modification, although the use of these targets in human gene therapy protocols has been hampered by low levels of transduction. We have shown previously that significant increases in the transduction of hematopoietic stem and progenitor cells with retroviral... |
9573222 | Ligand induction of retinoic acid receptors alters an acute infection by murine cytomegalovirus. | Here we report that administration of retinoids can alter the outcome of an acute murine cytomegalovirus (MCMV) infection. We show that a crucial viral control element, the major immediate-early enhancer, can be activated by retinoic acid (RA) via multiple RA-responsive elements (DR2) that bind retinoid X receptor-reti... |
9573218 | Characterization of determinants for envelope binding and infection in tva, the subgroup A avian sarcoma and leukosis virus receptor. | Tva is the cellular receptor for subgroup A avian leukosis and sarcoma virus (ALSV-A). The viral interaction domain of Tva is determined by a 40-residue, cysteine-rich module closely related to the ligand binding domain of the human low-density lipoprotein receptor (LDLR). In this report, we examined the role of the LD... |
29711243 | Anion-Templated Assembly of a Supramolecular Cage Complex. | The templating effect of the tetrafluoroborate ion leads to assembly of four Co<sup>II</sup> ions and six bridging ligands around this anion to give a tetrahedral complex with a bridging ligand along each edge and the anion trapped in the central cavity (shown below). Surprisingly under identical conditions but with Ni... |
29711236 | Formation of a Ring-Shaped Reduced "Metal Oxide" with the Simple Composition [(MoO<sub>3</sub> )<sub>176</sub> (H<sub>2</sub> O)<sub>80</sub> H<sub>32</sub> ]. | The largest inorganic molecular system so far, [(MoO<sub>3</sub> )<sub>176</sub> (H<sub>2</sub> O)<sub>80</sub> H<sub>32</sub> ] (1; the picture on the right shows the polyhedral representation), which has been characterized by X-ray structure analysis, possesses a cavity of diameter 2.3 nm and remarkably shows the sto... |
29711235 | A Dendritic Macrocyclic Organic Polyradical with a Very High Spin of S=10. | Designed as a ferromagnetically coupled spin pentamer, the macrocyclic polyradical 1 possesses an average spin of S=10 in the ground state. This is the highest spin quantum number that has yet been measured for an organic molecule. Ar=tBuC<sub>6</sub> H<sub>4</sub> . |
29711234 | Anion Control in the Self-Assembly of a Cage Coordination Complex. | An anion is encapsulated in the center of the new cage compound [Ni<sub>6</sub> (atu)<sub>8</sub> X]X<sub>3</sub> (X=Cl-for the structure see picture-or Br; Hatu=amidinothiourea). A combination of Lewis acid-base and hydrogen-bonding interactions cause the square-planar [Ni(Hatu)<sub>2</sub> ]<sup>2+</sup> units, after... |
29711233 | Characterization of Hydrogen-Bonded Supramolecular Assemblies by MALDI-TOF Mass Spectrometry after Ag<sup>+</sup> Labeling. | The high affinity of Ag<sup>+</sup> ions for aromatic π donors and cyano groups is exploited in a novel MALDI-TOF mass spectrometric method for the identification of hydrogen-bonded assemblies. The interaction with the Ag<sup>+</sup> ions-which, for example, can be complexed by two phenyl groups in a sandwich-type mann... |
29711231 | Supramolecular Daisy Chains. | Our childhoods may be recalled when a self-complementary cation, endowed with both a dibenzo[24]crown-8 macroring and a secondary dialkylammonium sidearm, self-assembles to form a two-component supramolecular architecture that is reminiscent of a daisy chain (depicted schematically on the right). This daisy-chain-like ... |
29711228 | Dual Recognition of Double-Stranded DNA by 2'-Aminoethoxy-Modified Oligonucleotides. | Simultaneous interaction of the 2'-aminoethoxy-modified oligonucleotides with the phosphodiester backbone (shown on the right, A) and with the bases through Hoogsteen base contacts (B) is seen at each base-pair step of the duplex DNA target. The electrostatic interaction between the protonated amino group and the negat... |
29711224 | Acetylenic Cyclophanes as Fullerene Precursors: Formation of C<sub>60</sub> H<sub>6</sub> and C<sub>60</sub> by Laser Desorption Mass Spectrometry of C<sub>60</sub> H<sub>6</sub> (CO)<sub>12</sub>. | A logical precursor of macrocycle C<sub>60</sub> H<sub>6</sub> , cyclophane C<sub>60</sub> H<sub>6</sub> (CO)<sub>12</sub> (1) represents a building block in a possible total synthesis of C<sub>60</sub> . In Fourier transform ion cyclotron resonance laser desorption mass spectroscopic experiments in the negative-ion mo... |
29711219 | From Disymmetric Molecules to Chiral Polymers: A New Twist for Supramolecular Synthesis? | A new branch of crystal engineering appears to have borne fruit: A noncovalently bonded network consisting of the complex illustrated as a stick model on the right is converted directly into a coordination polymer with a similar molecular architecture. The implications of the new work extend beyond the boundaries of co... |
29711218 | Synthesis and Association Behavior of [4.4.4.4.4.4]Metacyclophanedodecayne Derivatives with Interior Binding Groups. | Intriguing association behavior in solution is exhibited by the rigid macrocycle 1. For instance, it reacts with organic cations to give ternary complexes of the composition (1⋅cation)⋅1, and with analogous macrocycles without cyano groups it forms heteroaggregates. R=CO<sub>2</sub> C<sub>8</sub> H<sub>17</sub> . |
29711214 | Expression of Chirality by Achiral Coadsorbed Molecules in Chiral Monolayers Observed by STM. | The supramolecular packing mode of physisorbed monolayers built up by chiral isophthalic acid derivatives and coadsorbed achiral solvent molecules was imaged at the liquid/graphite interface with scanning tunneling microscopy (STM). The picture on the right shows the submolecularly resolved STM image of an enantiomorph... |
29711025 | Topochemical Conversion of a Hydrogen-Bonded Three-Dimensional Network into a Covalently Bonded Framework. | Thermal dehydration promotes the topochemical conversion of the hydrogen-bonded dimeric complex [{Zn(sala)(H<sub>2</sub> O)<sub>2</sub> }<sub>2</sub> ]⋅2 H<sub>2</sub> O (H<sub>2</sub> (sala)=N-(2-hydroxybenzyl)-L-alanine) to generate covalent [{Zn(sala)}<sub>n</sub> ]. X-ray crystallography reveals that hydrogen bondi... |
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