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9050802 | Intravenous and oral pharmacokinetic evaluation of a 2-hydroxypropyl-beta-cyclodextrin-based formulation of carbamazepine in the dog: comparison with commercially available tablets and suspensions. | Complexation of carbamazepine with 2-hydroxypropyl-beta-cyclodextrin was performed to provide improved formulations of this widely used antiepileptic drug. Based on this approach, liquid dosage forms were configured for both parenteral and oral use. Intravenous administration of an aqueous carbamazepine x 2-hydroxyprop... |
9045670 | Collagen II containing a Cys substitution for arg-alpha1-519. Homotrimeric monomers containing the mutation do not assemble into fibrils but alter the self-assembly of the normal protein. | A recombinant system was used to prepare human type II procollagen containing the substitution of Cys for Arg at alpha1-519 found in three unrelated families with early onset generalized osteoarthritis together with features of a mild chondrodysplasia probably best classified as spondyloepiphyseal dysplasia. In contras... |
9045637 | Conformational and functional differences between recombinant human lens alphaA- and alphaB-crystallin. | Human and other mammalian lens proteins are composed of three major crystallins: alpha-, beta-, and gamma-crystallin. alpha-Crystallin plays a prominent role in the supramolecular assembly required to maintain lens transparency. With age, the crystallins, especially alpha-crystallin, undergo posttranslational modificat... |
9045827 | Molecular characterization of the Bacillus stearothermophilus PV72 S-layer gene sbsB induced by oxidative stress. | S-layer protein variation from a hexagonally ordered (SbsA; 130 kDa) to a obliquely ordered (SbsB; 98 kDa) protein in Bacillus stearothermophilus PV72 is mediated by an increased oxygen supply. To elucidate the molecular basis of S-layer protein variation in B. stearothermophilus PV72, the sbsB gene, coding for the 98-... |
9045807 | Suppressor gene analysis reveals an essential role for sphingolipids in transport of glycosylphosphatidylinositol-anchored proteins in Saccharomyces cerevisiae. | Sphingolipids are normally necessary for growth of Saccharomyces cerevisiae cells, but mutant strains that bypass the need for sphingolipids have been identified. Such bypass mutants fail to grow under stressful conditions, including low pH (pH 4.1), when they lack sphingolipids. To begin to understand why sphingolipid... |
9032404 | In vitro transcription of human T-cell leukemia virus type 1 is RNA polymerase II dependent. | The HTLV-1 promoter directs RNA polymerase II transcription of viral genomic RNA in vivo. However, it has been reported that in vitro, a unique RNA polymerase, with characteristics of RNA polymerases II and III, is capable of HTLV-1 transcription (G. Piras, F. Kashanchi, M. F. Radonovich, J. F. Duvall, and J. N. Brady,... |
9032367 | In vitro genetic selection analysis of alfalfa mosaic virus coat protein binding to 3'-terminal AUGC repeats in the viral RNAs. | The coat proteins of alfalfa mosaic virus (AMV) and the related ilarviruses bind specifically to the 3' untranslated regions of the viral RNAs, which contain conserved repeats of the tetranucleotide sequence AUGC. The purpose of this study was to develop a more detailed understanding of RNA sequence and/or structural d... |
9032301 | Regulation of the cfos serum response element by C/EBPbeta. | Serum response element binding protein (SRE BP) is a novel binding factor present in nuclear extracts of avian and NIH 3T3 fibroblasts which specifically binds to the cfos SRE within a region overlapping and immediately 3' to the CArG box. Site-directed mutagenesis combined with transfection experiments in NIH 3T3 cell... |
9032241 | The decline in human Alu retroposition was accompanied by an asymmetric decrease in SRP9/14 binding to dimeric Alu RNA and increased expression of small cytoplasmic Alu RNA. | Alu interspersed elements are inserted into the genome by a retroposition process that occurs via dimeric Alu RNA and causes genetic disorders in humans. Alu RNA is labile and can be diverted to a stable left monomer transcript known as small cytoplasmic Alu (scAlu) RNA by RNA 3' processing, although the relationship b... |
9032232 | Effect of association with adenylyl cyclase-associated protein on the interaction of yeast adenylyl cyclase with Ras protein. | Posttranslational modification of Ras protein has been shown to be critical for interaction with its effector molecules, including Saccharomyces cerevisiae adenylyl cyclase. However, the mechanism of its action was unknown. In this study, we used a reconstituted system with purified adenylyl cyclase and Ras proteins ca... |
9023108 | DNA binding and subunit interactions in the type I methyltransferase M.EcoR124I. | The type I DNA methyltransferase M.EcoR124I consists of two methylation subunits (HsdM) and one DNA recognition subunit (HsdS). When expressed independently, HsdS is insoluble, but this subunit can be obtained in soluble form as a GST fusion protein. We show that the HsdS subunit, even as a fusion protein, is unable to... |
24022948 | Heterosupramolecular Chemistry: Self-Assembly of an Electron Donor (TiO2 Nanocrystallite)-Acceptor (Viologen) Complex. | A TiO2 nanocrystallite has been modified to recognise and selectively bind, by complementary hydrogen bonding, a uracil substrate incorporating a viologen moiety. Band-gap excitation of the self-assembled donor (TiO2 nanocrystallite)-acceptor (viologen) complex results in electron transfer. Some implications of these f... |
21639191 | Intrinsic selectivity in capillary electrophoresis for chiral separations with dual cyclodextrin systems. | Defined as the ratio of the affinity factors of the analytes for a complexing agent, the intrinsic selectivity is representative of the very nature of the complexing agent. When more than one complexing agent are present in the background electrolyte, it is possible to define several intrinsic selectivities according t... |
21639190 | Selectivity in capillary electrophoresis: application to chiral separations with cyclodextrins. | In order to accurately evaluate the performances of any electrolyte medium, a clear concept of selectivity in capillary electrophoresis and related electroseparation techniques is proposed. Selectivity is defined as the ratio of the affinity factors of both analytes for a separating agent (phase, pseudophase, or comple... |
21639186 | Capillary Electrokinetic Chromatography Employing p-(Carboxyethyl)calix[n]arenes as Running Buffer Additives. | Calixarenes, a class of macrocyclic phenolic compounds with a basket-like shape, are used as capillary electrophoresis reagents for separations of native and substituted polycyclic aromatic hydrocarbons. The p-(carboxyethyl)calix[n]arenes reported herein are a series of charged, moderately water soluble macrocyclic mol... |
17029832 | Significant discrepancies between van't Hoff and calorimetric enthalpies. III. | The study of a wide variety of reversible reactions in solution indicates that the enthalpy, DeltaH(vH), which controls the temperature variation of the equilibrium constant for a reaction, can seldom, if ever, be taken to be independent of the temperature. It is also found in most cases that the values for DeltaH(vH),... |
9056326 | Inclusion of Volatile Organic Compounds into Natural Cyclodextrins and Their Branched Cyclodextrins in the Gaseous Phase | The adsorption isotherms of water, the differential heat of adsorption, and the entropy of adsorbed water were investigated to elucidate the structure of stability of cyclodextrins (CyD) and branched CyD's. The amount adsorbed on branched CyD's increased with increasing relative humidity. The steep rise in the amount a... |
12223613 | Polyamines and Pectins (I. Ion Exchange and Selectivity). | The ion-binding and -exchange properties of putrescine, spermidine, and spermine on purified walls of carrot (Daucus carota L.) cell suspensions were investigated by producing ion-exchange isotherms and comparing them with the behavior of Na+, Mg2+, and Ca2+. The cation exchange capacity of the carrot cell walls was 0.... |
9127274 | Simultaneous determination of the elimination profiles of the individual enantiomers of racemic isoproterenol using capillary electrophoresis and microdialysis sampling. | Microdialysis sampling and capillary electrophoresis with electrochemical detection (CE-EC) were used in combination to simultaneously define the elimination profile of each enantiomer of isoproterenol (ISP) administered as a racemic mixture to Sprague-Dawley rats. Resolution of the enantiomers of ISP was accomplished ... |
9113402 | Assemblases and coupling proteins in thick filament assembly. | Thick filaments are stable assemblies of myosin that are characteristic of specific muscle types from both vertebrates and invertebrates. In general, their structure and assembly require remarkably precise determination of lengths and diameters, structural differentiation and nonequivalence of myosins, a high degree of... |
9157846 | [Cyclic oligonucleotides. II. Regularities in the formation of polycyclic structures]. | Cyclization of a 38-mer oligodeoxyribonucleotide on a cyclic template was studied by the chemical and enzymic ligation methods. Both structures and yields of the reaction products depended on the ligation method and the nucleotide and template sequences. The chemical ligations resulted in the formation of catenanes, wh... |
9109641 | Rewarding affective properties of intra-nucleus accumbens injections of testosterone. | On alternating days, adult male Long-Evans rats implanted with bilateral cannulas in the nucleus accumbens received intracerebral injections of testosterone in a water-soluble cyclodextrin inclusion complex (0.125, 0.25, or 0.5 microg/0.5 microl saline) or saline immediately prior to being confined for 30 min to 1 of 2... |
9118001 | Human enzymatic activities related to the therapeutic administration of chitin derivatives. | Three cases are presented where modified chitins have been extensively administered to volunteers, as dressings for wounded soft and bone tissues, as anticholesterolemic dietary foods, and in the controlled delivery of anti-inflammatory drugs. The interactions of the modified chitins with human enzymes is critically ex... |
9088644 | Isolation and characterization of X chromosome-derived DNA sequences from a dioecious plant Melandrium album. | A number of X chromosome DNA sequences have been isolated from a dioecious plant, Melandrium album (syn. Silene latifolia), using chromosome microdissection followed by degenerate oligonucleotideprimed polymerase chain reaction (DOP-PCR) amplification. Six DNA clones were selected and further characterized by DNA/DNA h... |
9088643 | Meiotic behaviour of holocentric chromosomes: orientation and segregation of autosomes in Triatoma infestans (Heteroptera). | The meiotic behaviour of the holocentric chromosomes of the heteropteran species Triatoma infestans has been analysed by means of orcein staining and C-banding on squashed spermatocytes. We have focused our analysis on chromosome 3, which shows a large distal heterochromatic band at one of the ends of both homologues. ... |
9088642 | CMA3-banding pattern and fluorescence in situ hybridization with 18S rRNA genes in zebrafish chromosomes. | This study provides new data on zebrafish chromosomes, obtained from the chromomycin A3-banding pattern and mapping of 18S rRNA genes by fluorescence in situ hybridization (FISH). C-banding and Agstaining were also performed to analyse whether variation in heterochromatin and Ag-nucleolus organizer regions (NORs) exist... |
9088641 | Molecular cytogenetics of Alstroemeria: identification of parental genomes in interspecific hybrids and characterization of repetitive DNA families in constitutive heterochromatin. | The genus Alstroemeria consists of diploid (2n = 2x = 16) species originating mainly from Chile and Brazil. Most cultivars are triploid or tetraploid interspecific hybrids. C-banding of eight species revealed obvious differentiation of constitutive heterochromatin within the genus. The present study focused on the mole... |
9088640 | High-resolution fluorescence in situ hybridization of human Y-linked genes on released chromatin. | Genes within the differential region of the human Y chromosome do not recombine, and therefore the determination of their location depends on physical mapping. Yeast artificial chromosome (YAC) contigs spanning the euchromatic region of the human Y have become a powerful tool for the generation of an overlapping clone ... |
9088639 | Cytogenetics of the genus Leporinus (Pisces, Anostomidae). 1. Karyotype analysis, heterochromatin distribution and sex chromosomes. | Cytogenetic analyses (Giemsa staining, C-banding, AgNO3 labelling of nucleolus organizer regions (NORs) and staining with base-specific fluorochromes) were performed on the South American fish species Leporinus friderici, L. obtusidens and L. elongatus. The overall karyotypic structure, position of NORs, as well as the... |
9088638 | Zoo-FISH analysis: the American mink (Mustela vison) closely resembles the cat karyotype. | The 24 human chromosome-specific DNA probes were used to visualize segments of conserved synteny on metaphase chromosomes of the American mink (Mustela vison). A comparison with the hitherto known gene mapping data shows a high degree of correspondence. The human chromosomes were found conserved in only 34 segments of ... |
9084038 | Characterization of an acetylcholine receptor gene of Haemonchus contortus in relation to levamisole resistance. | The anthelminitic drug levamisole is thought to bind to nicotinic acetylcholine receptors of nematodes. It is possible that resistance to this drug is associated with either a change in binding characteristics or a reduction in the number of nicotinic acetylcholine receptors. Therefore, the molecular mechanism of levam... |
9080316 | Assay for the (R)- and (S)-enantiomers of salsolinols in biological samples and foods with ion-pair high-performance liquid chromatography using beta-cyclodextrin as a chiral mobile phase additive. | A chromatographic procedure was devised for the quantitative determination of the enantiomers of salsolinol and N-methylsalsolinol, which are biologically important alkaloids. The enantiomers of salsolinol and N-methylsalsolinol were completely separated using beta-cyclodextrin in a reversed-phase ion-pair system. The ... |
9080136 | Analysis of domoic acid and isomers in seafood by capillary electrophoresis. | Methods for the analysis of domoic acid (DA) based upon capillary electrophoresis (CE) combined with UV absorbance detection were investigated. DA could be analyzed using bare fused-silica capillaries in either the cationic or anionic mode with acidic or basic buffer systems, respectively. Highest performance, in terms... |
9080133 | The effect of cyclodextrin modifiers on electrophoretic separation of aromatic hydrocarbons. | Cyclodextrin-modified capillary electrophoresis has been developed for separation and analysis of benzene and its derivatives. The procedure used a mixture of negatively charged sulfobutyl ether-beta-cyclodextrin (SB beta CD) and neutral hydroxypropyl-beta-cyclodextrin (HP beta CD) to effect differential distribution (... |
9080132 | Capillary electrophoresis of organotin compounds with indirect UV detection. | A capillary electrophoresis (CE)-indirect UV absorbance detection method for organotin compounds is described. The five triorganotin cations, viz., trimethyltin (TMT), triethyltin (TET), tripropyltin (TPT), tributyltin (TBT) and triphenyltin (TPhT), were efficiently separated by CE in 10 min with a 5 mM acetate buffer ... |
9080130 | Stereoselective analysis of herbicides by capillary electrophoresis using sulfobutyl ether beta-cyclodextrin as chiral selector. | Capillary zone electrophoresis has been used for the enantiomeric separation of several herbicides. Different beta-cyclodextrin (CD) derivatives have been investigated for chiral separations and among them the negatively charged sulfobutyl ether beta-cyclodextrin (SBE-beta-CD) proved to be effective for the stereo-sele... |
9078259 | Metabolism of 27-, 25- and 24-hydroxycholesterol in rat glial cells and neurons. | The metabolism of 27-, 25- and 24-hydroxycholesterol in cultures of rat astrocytes, Schwann cells and neurons was studied. 27- and 25-Hydroxycholesterol, but not 24-hydroxycholesterol, underwent 7 alpha-hydroxylation with subsequent oxidation to 7 alpha-hydroxy-3-oxo-delta 4 steroids in all three cell types. When cells... |
9070244 | Formation of recombinant triple-helical [alpha 1(IV)]2 alpha 2(IV) collagen molecules in CHO cells. | Collagen IV molecules represent a major structural component of basement membranes providing a network of support for the supramolecular structure. Like other collagens, collagen IV forms a triple-helical molecule composed of three alpha chains. Six different alpha chains exist for collagen IV, although the most common... |
9069675 | A monoclonal antibody, 169.1, against canine leukocyte surface antigen identifies cytoskeletal components in epithelial cells and peripheral neurons. | Monoclonal antibodies were produced by immunizing BALB/c mice with freshly prepared canine thymocytes and peripheral blood leukocytes. Flow cytometric analysis of canine peripheral blood leukocytes showed that an antibody, designated 169.1, recognized about 60% of non-lymphoid cells, but reacted with less than 3% of ly... |
9066314 | A novel aspect of photodynamic action: induction of recurrent spikes in cytosolic calcium concentration. | Effects of photodynamic action of gadolinium porphyrin-like macrocycle B (PLMGdB) on cytosolic Ca2+ concentration, [Ca2+]c, was investigated in isolated rat pancreatic acini. The PLMGdB alone or light alone (2 min) had no effect on [Ca2+]c. Cell-bound PLMGdB upon brief (0.5-2.0 min) light activation triggered recurrent... |
9065804 | In vitro mutagenicity of the plasmacytomagenic agent pristane (2,6,10,14-tetramethylpentadecane). | Pristane is known to induce a distinct type of B-cell-derived malignant lymphoma, plasmacytoma, after administration into the peritoneal cavity of genetically susceptible BALB/cAnPt mice. Since the mechanism of pristane-induced plasmacytoma development is poorly understood, we chose to examine the possibility that pris... |
9063563 | Proline is a protein solubilizing solute. | The effect of proline on the prevention of trichloroacetic acid (TCA)-induced protein precipitation is studied. It is found that proline at high concentrations (> 4.0 M) completely prevents TCA-induced precipitation of hen egg white lysozyme. Other osmolytes such as ethylene glycol, glycerol and sucrose fail to prevent... |
9063562 | Effect on product specificity of cyclodextrin glycosyltransferase by site-directed mutagenesis. | Cyclodextrin glycosyltransferase (CGTase; EC 2.4.1.19) catalyzes the degradation of starch into cyclodextrins through an intramolecular transglycosylation reaction. Tyr-89, Asn-94, and Tyr-100 are located near the putative active center. To analyze their roles in product specificity, Tyr-89, Asn-94, and Tyr-100 of CGTa... |
9061636 | Shaker B K+ conductance in Na+ solutions lacking K+ ions: a remarkably stable non-conducting state produced by membrane depolarizations. | 1. Shaker B K+ channels, expressed in the insect cell line Sf9, were studied in zero K+, Na+ or N-methyl-D-glucamine (NMG)-containing solutions. In the absence of K+ ions on both sides of the membrane, the K+ conductance collapsed with the delivery of short depolarizing pulses that activated the channels. The collapse ... |
9118452 | Spectroscopic characterization of the inclusion complex of a luteinizing hormone-releasing hormone agonist, buserelin acetate, with dimethyl-beta-cyclodextrin. | Inclusion complexation of buserelin acetate, and agonist of luteinizing hormone-releasing hormone, with dimethyl-beta-cyclodextrin (DM-beta-CyD) in aqueous solution was studied spectroscopically and its mode of interaction was assessed. Ultraviolet absorption and circular dichroism (CD) spectroscopies indicate that the... |
9057985 | Inhibitory effect of acyl-CoA and acyl-carnitine compounds on the ischemia-inducing activity of Bordetella heat-labile toxin in guinea pig skin. | The ability of Bordetella heat-labile toxin (HLT) to induce ischemic lesions after intracutaneous injection to guinea pig skin was lost following incubation at 37 degrees C with long-chain saturated acyl-CoA and acyl-carnitine compounds. Short-chain unsaturated acyl-CoA compounds, however, were less potent in inhibitin... |
9055185 | Absorption of ciprofloxacin and norfloxacin when administered as niosome-encapsulated inclusion complexes. | An attempt has been made to design suitable niosome-encapsulated drug delivery system for ciprofloxacin and norfloxacin. Encapsulation of ciprofloxacin and norfloxacin in niosomes was investigated and the nasal and intestinal absorption of the products studied. More than 80% of the drugs were successfully encapsulated ... |
9055181 | Fluorimetric studies of the formation of riboflavin-beta-cyclodextrin inclusion complex: determination of the stability constant by use of a non-linear least-squares model. | The non-linear least-squares model for calculation of the stability constant (Kst) of a drug-cyclodextrin complex has been used in fluorimetry studies. Complexation of riboflavin with beta-cyclodextrin (beta-CyD) was monitored fluorimetrically by measuring changes in the fluorescence intensity of the vitamin in the pre... |
9081695 | Remodeling and shuttling. Mechanisms for the synergistic effects between different acceptor particles in the mobilization of cellular cholesterol. | In normal physiology, cells are exposed to cholesterol acceptors of different sizes simultaneously. The current study examined the possible interactions between two different classes of acceptors, one large (large unilamellar phospholipid vesicles, LUVs) and one small (HDL or other small acceptors), added separately or... |
9051290 | Alterations of the benzodiazepine site of rat alpha 6 beta 2 gamma 2-GABAA receptor by replacement of several divergent amino-terminal regions with the alpha 1 counterparts. | 1. The benzodiazepine site of the alpha 6 beta 2 gamma 2 subtype of gamma-aminobutyric acidA (GABAA) receptors is distinguishable from that of the alpha 1 beta 2 gamma 2 subtype by its inability to interact with classical benzodiazepines (i.e., diazepam) and its agonistic response to Ro 15-1788, which behaves as an ant... |
9050083 | Rewarding effect of the neuroactive steroid 3 alpha-hydroxy-5 alpha-pregnan-20-one in mice. | The GABAA-receptor agonist neuroactive steroid 3 alpha-hydroxy-5 alpha-pregnan-20-one (3 alpha,5 alpha-P) has anxiolytic and locomotor stimulant effects and shares some subjective properties with benzodiazepines, barbiturates and ethanol, but there have been no studies of its reinforcing or rewarding effects. The prese... |
9049302 | Rapid stimulation of a soybean protein-serine kinase that phosphorylates a novel bZIP DNA-binding protein, G/HBF-1, during the induction of early transcription-dependent defenses. | The G-box (CACGTG) and H-box (CCTACC) cis elements function in the activation of phenylpropanoid biosynthetic genes involved in the elaboration of lignin precursors, phytoalexins and the secondary signal salicylic acid as early responses to pathogen attack. We have isolated a soybean cDNA encoding a novel bZIP protein,... |
9048908 | Probing the substrate specificity for lipases. II. Kinetic and modeling studies on the molecular recognition of 2-arylpropionic esters by Candida rugosa and Rhizomucor miehei lipases. | Racemic arylpropionic esters 1-3, precursors of therapeutically important non-steroidal antiinflammatory drugs, were subjected to hydrolyses in the presence of either Candida rugosa or Rhizomucor miehei crude lipases. The hydrolyses of 1 and 2 proved to be highly enantioselective, whereas 3 was not transformed at all. ... |
9047366 | A 29 residue region of the sarcomeric myosin rod is necessary for filament formation. | Myosin is a motor protein whose functional unit in the sarcomere is the thick filament. The myosin molecule is capable of self-assembly into thick filaments through its alpha-helical coiled-coil rod domain. To define more precisely the sequence requirements for this assembly, segments of the human fast IId skeletal myo... |
9047309 | Modulation of magainin 2-lipid bilayer interactions by peptide charge. | Magainin 2, an antimicrobial peptide from Xenopus skin, assumes an amphiphilic helix when bound to acidic phospholipids, forming a pore composed of a dynamic, peptide-lipid supramolecular complex [Matsuzaki et al. (1996) Biochemistry 35, 11361-11368]. Upon the disintegration of the pore, a fraction of the peptide molec... |
9046341 | Meta-substituted benzofused macrocyclic lactams as zinc metalloprotease inhibitors. | The design, synthesis, and biochemical profile of meta-substituted benzofused macrocyclic lactams are described. The meta-substituted benzofused macrocyclic lactams were designed to have a degree of flexibility allowing the amide bond to occupy two completely different conformations while maintaining sufficient rigidit... |
9046340 | Ortho-substituted benzofused macrocyclic lactams as zinc metalloprotease inhibitors. | The design and preparation of ortho-substituted benzofused macrocyclic lactams are described. The benzofused macrocyclic lactams were designed as neutral endopeptidase 24.11 (NEP) inhibitors. Docking studies were carried out in a model of thermolysin (TLN) using the MACROMODEL and QXP modeling programs to select suitab... |
9045882 | Cyclodextrins as catalysts for the removal of cholesterol from macrophage foam cells. | Low concentrations of cyclodextrins (< 1.0 mM) added to serum act catalytically, accelerating the exchange of cholesterol between cells and lipoproteins. J774 macrophages incubated with serum and 2-hydroxypropyl-beta-cyclodextrin (< or = 1 mM) released fivefold more labeled cholesterol than with serum alone. Increased ... |
9041642 | Conformational stability of pGEX-expressed Schistosoma japonicum glutathione S-transferase: a detoxification enzyme and fusion-protein affinity tag. | A glutathione S-transferase (Sj26GST) from Schistosoma japonicum, which functions in the parasite's Phase II detoxification pathway, is expressed by the Pharmacia pGEX-2T plasmid and is used widely as a fusion-protein affinity tag. It contains all 217 residues of Sj26GST and an additional 9-residue peptide linker with ... |
9041053 | Protein interactions during assembly of the enamel organic extracellular matrix. | Enamel is the outermost covering of teeth and contains the largest hydroxyapatite crystallites formed in the vertebrate body. Enamel forms extracellularly through the ordered assembly of a protein scaffolding that regulates crystallite dimensions. The two most studied proteins of the enamel extracellular matrix (ECM) a... |
9040102 | Binding of cyclodextrins to alicyclic and aromatic substrates: complex formation of alpha-, beta-, and gamma-cyclodextrins with substituted cyclohexanecarboxylic acids and phenylalkanoic acids. | Complex binding constants of the three native cyclodextrins with seven cyclohexane derivatives (all possessing the carboxylic acid group) and with the series C6H5(CH2)nCOOH (n = 0 to 4) were measured in aqueous solution at 25 degrees C by potentiometry and the solubility method. These results, combined with literature ... |
9040099 | Effect of alkyl chain length and degree of substitution on the complexation of sulfoalkyl ether beta-cyclodextrins with steroids. | This study was designed to test how the sulfoalkyl ether (SAE) modification of beta-cyclodextrin (beta-CD) affects the binding capacity of testosterone and progesterone, thereby enhancing their solubility. The SAE-beta-CD derivatives contain either sulfopropyl ether (SPE) or sulfobutyl ether (SBE) groups on the 2-, 3-,... |
9040088 | Pharmaceutical applications of cyclodextrins. III. Toxicological issues and safety evaluation. | The objective of this review is to summarize recent findings on the safety profiles of three natural cyclodextrins (alpha-, beta- and gamma-CDs) and several chemically modified CDs. To demonstrate the potential of CDs in pharmaceutical formulations, their stability against non-enzymatic and enzymatic degradations in va... |
9039959 | Computation of the binding of fully flexible peptides to proteins with flexible side chains. | Docking algorithms play an important role in the process of rational drug design and in understanding the mechanism of molecular recognition. An important determinant for successful docking is the extent to which the configurational space (including conformational changes) of the ligand/receptor system is searched. Her... |
9038348 | Possible roles of inositol 1,4,5-trisphosphate 3-kinase B in calcium homeostasis. | Some aspects of the roles of inositol trisphosphate (Insp3) and inositol tetrakisphosphate (Insp4) in Ca2+ homeostasis in terms of inositol trisphosphate 3-kinase B (IP3K-B) localization and activity are discussed. The model that we propose is also compatible with IP3K-B participating in the widely reported phenomenon ... |
9038341 | Nonhomologous RNA recombination in a cell-free system: evidence for a transesterification mechanism guided by secondary structure. | Extensive nonhomologous recombinations occur between the 5' and 3' fragments of a replicable RNA in a cell-free system composed of pure Qbeta phage replicase and ribonucleoside triphosphates, providing direct evidence for the ability of RNAs to recombine without DNA intermediates and in the absence of host cell protein... |
9037092 | Interconversion of red opsin isoforms by the cyclophilin-related chaperone protein Ran-binding protein 2. | Ran-binding protein 2 (RanBP2) (type II) is a retinal cyclophilin-related protein that binds Ran-GTPase. Type I cyclophilin is a shorter, alternatively spliced isoform of RanBP2. Recently, we showed that the Ran-binding domain 4 (RBD4)/cyclophilin (CY) supradomain of RanBP2 acts both in vitro and in vivo as a specific ... |
9037070 | Zinc porphyrins: potent inhibitors of hematopoieses in animal and human bone marrow. | The effects of selected heme analogues on heme oxygenase activity in tissues and on human and rabbit bone marrow hematopoietic colony growth were examined. Zinc protoporphyrin (ZnPP) and zinc mesoporphyrin (ZnMP), at concentrations ranging between 1 and 20 microM, produced significant inhibition of human and rabbit bon... |
9037005 | A new approach for containment of microorganisms: dual control of streptavidin expression by antisense RNA and the T7 transcription system. | The use of microorganisms in the open environment would be of less concern if they were endowed with programmed self-destruction mechanisms. Here, we propose a new genetic design to increase the effectiveness of cell suicide systems. It ensures very tight control of the derepression of cell death by the combination of ... |
9034147 | Epitope location in the Cryptococcus neoformans capsule is a determinant of antibody efficacy. | Monoclonal antibodies (mAbs) to the polysaccharide capsule of Cryptococcus neoformans can prolong survival in mice. However, the properties of antibodies that mediate protection are not fully understood. The IgM mAbs 12A1 and 13F1 originated from the same B cell and differ only by somatic mutations in their variable re... |
9033287 | Intestinal epithelial restitution. Involvement of specific laminin isoforms and integrin laminin receptors in wound closure of a transformed model epithelium. | Disruptions in the mucosal lining of the gastrointestinal tract reseal by epithelial cell migration, a process termed restitution. We examined the involvement of laminin isoforms and their integrin receptors in restitution using the intestinal epithelial cell line T84. T84 cells express primarily laminins 5, 6, and 7 a... |
9032467 | Influence of mutations in tissue factor on the fine specificity of macromolecular substrate activation. | The C-terminal fibronectin-type-III-like module of the tissue factor (TF) extracellular domain plays a requisite role in the activation of macromolecular substrates by factor VIIa (VIIa) in complex with TF. Unlike the mutations Lys165-->Ala, Lys166-->Ala in TF, which prevent efficient proteolysis of factor X, we found ... |
9032456 | The pseudoazurin gene from Thiosphaera pantotropha: analysis of upstream putative regulatory sequences and overexpression in Escherichia coli. | The pseudoazurin gene from Thiosphaera pantotropha has been cloned and sequenced. The deduced amino acid sequence showed that the protein contains an unusually alanine-rich signal peptide, 22 amino acid residues in length, which targets the protein to the periplasm. This pseudoazurin was expressed in large amounts in t... |
9032450 | Quality control of glycosylphosphatidylinositol anchor attachment in mammalian cells: a biochemical study. | hGHDAF28 is a chimaeric protein consisting of human growth hormone fused to a crippled signal sequence for glycosylphosphatidylinositol (GPI)-anchor addition from decay-accelerating factor, and serves as a model for quality control of GPI-anchor addition. hGHDAF28 is retained in a pre-Golgi compartment and degraded int... |
9030362 | Itraconazole cyclodextrin solution: the role of in vitro susceptibility testing in predicting successful treatment of HIV-related fluconazole-resistant and fluconazole-susceptible oral candidosis. | <h4>Objectives</h4>This study assessed the ability of in vitro susceptibility testing of clinical Candida isolates to predict in vivo response to itraconazole cyclodextrin solution.<h4>Methods</h4>One hundred specimens were obtained from HIV-positive patients with oral thrush, of which 72 speciments were from patients ... |
9025272 | The crystal and molecular structure of (HgL2)n (L = 4,6-dimethylpyrimidine-2-thiolate)--an unusual helical supramolecular assembly in solid phase: in search of a new antidote to mercury poisoning. | An X-ray crystallographic study reveals that in solid phase, 4,6-dimethylpyrimidine-2-thiol (4,6Me2 Pm2SH) forms a multinuclear complex with mercury, containing an open HgN3S2 core and exhibiting a helix-like polymerization through repetitive distant Hg(sp3d) ... N(sp2) interactions along the b axis of the lattice. The... |
9024688 | A multistep, ATP-dependent pathway for assembly of human immunodeficiency virus capsids in a cell-free system. | To understand the mechanism by which human immunodeficiency virus type 1 (HIV) capsids are formed, we have reconstituted the assembly of immature HIV capsids de novo in a cell-free system. Capsid authenticity is established by multiple biochemical and morphologic criteria. Known features of the assembly process are clo... |
9024684 | Identification of protein p270/Tpr as a constitutive component of the nuclear pore complex-attached intranuclear filaments. | Using a monoclonal antibody, mAb 203-37, we have identified a polypeptide of M(r) approximately 270 kD (p270) as a general constituent of the intranuclear filaments attached to the nucleoplasmic annulus of the nuclear pore complex (NPC) in diverse kinds of vertebrate cells. Using cDNA cloning and immunobiochemistry, we... |
9024683 | Assembly of CENP-A into centromeric chromatin requires a cooperative array of nucleosomal DNA contact sites. | We investigated the requirements for targeting the centromeric histone H3 homologue CENP-A for assembly at centromeres in human cells by transfection of epitope-tagged CENP-A derivatives into HeLa cells. Centromeric targeting is driven solely by the conserved histone fold domain of CENP-A. Using the crystal structure o... |
9023929 | Proteinaceous factor(s) in culture supernatant fluids of bifidobacteria which prevents the binding of enterotoxigenic Escherichia coli to gangliotetraosylceramide. | We have examined the competitive binding of several species of Bifidobacterium and Escherichia coli Pb176, an enterotoxigenic E. coli (ETEC) strain, to gangliotetraosylceramide (asialo GM1 or GA1), a common bacterium-binding structure, and identified a factor(s) in the Bifidobacterium culture supernatant fluid that inh... |
9023207 | DNA-binding determinants of sigma 54 as deduced from libraries of mutations. | PCR mutagenesis was used to obtain libraries of mutations in the region between amino acids 300 and 400 in the DNA-binding domain of Escherichia coli sigma 54. Two hundred changes that did not alter function were identified. These were compared with a somewhat smaller number of changes that did alter function. Several ... |
9023183 | Critical base pairs and amino acid residues for protein-DNA interaction between the TyrR protein and tyrP operator of Escherichia coli. | In Escherichia coli K-12, the repression of tyrP requires the binding of the TyrR protein to the operator in the presence of coeffectors, tyrosine and ATP. This operator contains two 22-bp palindromic sequences which are termed TyrR boxes. Methylation, uracil, and ethylation interference experiments were used to identi... |
9023179 | X-ray photoelectron spectroscopy analysis of whole cells and isolated cell walls of gram-positive bacteria: comparison with biochemical analysis. | The surface chemical composition of whole cells and isolated cell walls of four coryneform bacteria and of a Bacillus brevis strain has been determined by X-ray photoelectron spectroscopy (XPS). The XPS data were converted into concentrations of model compounds: peptides, polysaccharides, and hydrocarbonlike compounds.... |
9020071 | A functional model related to cytochrome c oxidase and its electrocatalytic four-electron reduction of O2. | A cytochrome c oxidase model that consists of a cobalt(II) porphyrin with a copper(I) triazacyclononane macrocycle fastened on the distal face and an imidazole covalently attached to the proximal face has been synthesized and characterized. Redox titrations with molecular oxygen (O2) and cobaltocene were carried out, a... |
9017222 | High-resolution scanning tunneling microscopy of fully hydrated ripple-phase bilayers. | A modified freeze-fracture replication technique for use with the scanning tunneling microscope (STM) has provided a quantitative, high-resolution description of the waveform and amplitude of rippled bilayers in the P beta' phase of dimyristoylphosphatidylcholine (DMPC) in excess water. The ripples are uniaxial and asy... |
9017221 | The conformation of DNA packaged in bacteriophage G. | When packaged in a bacteriophage capsid, double-stranded DNA occupies a cavity whose volume is roughly twice the volume of the DNA double helix. The data thus far have not revealed whether the compactness of packaged bacteriophage DNA is achieved by folding of the DNA, undirectional winding of the DNA, or a combination... |
9017220 | On the role of assembly kinetics in determining the structure of clathrin cages. | The process of clathrin self-assembly into closed shells with the Fullerene structure is investigated. It is argued that the shell size distribution is governed by the kinetics of assembly and depends on the rate of growth controlled by the free clathrin concentration. The particularly abundant small structures--the "t... |
9017219 | On a possible microscopic mechanism underlying the vapor pressure paradox. | We investigate the free energy and the profile of the displacement field in a stack of sterically interacting smectic multilayers bounded by surfaces under tension. We show that this tension can lead to a significant change in the multilayer free energy. It creates an additional long-range attraction (a pseudo-Casimir ... |
9017192 | Simulation studies of alamethicin-bilayer interactions. | Alamethicin is an alpha-helical peptide that forms voltage-activated ion channels. Experimental data suggest that channel formation occurs via voltage-dependent insertion of alamethicin helices into lipid bilayers, followed by self-assembly of inserted helices to form a parallel helix bundle. Changes in the kink angle ... |
9017191 | The contribution of electrostatic and van der Waals interactions to the stereospecificity of the reaction catalyzed by lactate dehydrogenase. | Continuum electrostatic calculations in conjunction with molecular dynamics simulations have been used to investigate the source of the stereospecificity in the hydride transfer reaction catalyzed by lactate dehydrogenase (LDH). These studies show that favorable electrostatic interactions between the carboxamide group ... |
9016648 | Simultaneous display of different peptides on the surface of filamentous bacteriophage. | We have developed a new system for producing hybrid virions of filamentous bacteriophage fd simultaneously displaying two different peptides by infecting cells harbouring a plasmid containing a modified gene VIII with an engineered bacteriophage carrying a second and different copy of a modified gene VIII. The simultan... |
9016620 | Characterization of a RecA/RAD51 homologue from the hyperthermophilic archaeon Pyrococcus sp. KOD1. | The Pk-rec gene, encoding a RecA/RAD51 homologue from the hyperthermophilic archaeon Pyrococcussp. KOD1, was expressed in Escherichia coli. The recombinant Pk-REC was purified to homogeneity and was shown to be in a dimeric form. A striking property of the purified recombinant Pk-REC was the unusual DNase activity on b... |
9016606 | Potassium-resistant triple helix formation and improved intracellular gene targeting by oligodeoxyribonucleotides containing 7-deazaxanthine. | Triple helix formation by purine-rich oligonucleotides in the anti-parallel motif is inhibited by physiological concentrations of potassium. Substitution with 7-deazaxanthine (c7X) has been suggested as a strategy to overcome this effect. We have tested this by examining triple helix formation both in vitro and in vivo... |
9116147 | In vitro inhibition of the biological activity of follicle-stimulating hormone by anti-peptide antisera representing the human follicle-stimulating hormone beta subunit sequence 33-53. | There are few male contraceptive methods, and research is required to broaden the scope of available male antifertility methods. Two approaches toward hormonal contraception are currently being investigated. The first relies on elimination of testosterone while the second is based upon immunizations against FSH. Howeve... |
9009349 | Porphyromonas gingivalis fimbria-stimulated bone resorption is inhibited through binding of the fimbriae to fibronectin. | Our most recent study demonstrated that fibronectin is one of the Porphyromonas gingivalis fimbria-binding proteins. In this present study, we demonstrate with mouse embryonic calvarial cells that P. gingivalis fimbria-stimulated bone resorption is inhibited by human fibronectin. The fibronectin inhibition was dose and... |
9006052 | Properties and gene structure of the Thermotoga maritima alpha-amylase AmyA, a putative lipoprotein of a hyperthermophilic bacterium. | Thermotoga maritima MSB8 has a chromosomal alpha-amylase gene, designated amyA, that is predicted to code for a 553-amino-acid preprotein with significant amino acid sequence similarity to the 4-alpha-glucanotransferase of the same strain and to alpha-amylase primary structures of other organisms. Upstream of the amyla... |
9006039 | Genetic analysis of the catalytic domain of the chemotaxis-associated histidine kinase CheA. | Escherichia coli cells express two forms of CheA, the histidine kinase associated with chemotaxis. The long form, CheA(L), plays a critical role in chemotactic signal transduction by phosphorylating two chemotaxis-associated response regulators, CheY and CheB. CheA(L) first autophosphorylates amino acid His-48 before i... |
9006033 | Lack of functional complementation between Bordetella pertussis filamentous hemagglutinin and Proteus mirabilis HpmA hemolysin secretion machineries. | The gram-negative bacterium Bordetella pertussis has adapted specific secretion machineries for each of its major secretory proteins. In particular, the highly efficient secretion of filamentous hemagglutinin (FHA) is mediated by the accessory protein FhaC. FhaC belongs to a family of outer membrane proteins which are ... |
9006024 | Pristinamycin I biosynthesis in Streptomyces pristinaespiralis: molecular characterization of the first two structural peptide synthetase genes. | Two genes involved in the biosynthesis of the depsipeptide antibiotics pristinamycins I (PI) produced by Streptomyces pristinaespiralis were cloned and sequenced. The 1.7-kb snbA gene encodes a 3-hydroxypicolinic acid:AMP ligase, and the 7.7-kb snbC gene encodes PI synthetase 2, responsible for incorporating L-threonin... |
9006023 | Purification of peptide synthetases involved in pristinamycin I biosynthesis. | Several assays of pristinamycin I synthetases based on adenylate or thioester formation were developed. Purification to near homogeneity of these enzymatic activities from cell extracts of Streptomyces pristinaespiralis showed that three enzymes could activate all pristinamycin I precursors. SnbA, a 3-hydroxypicolinic ... |
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