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11516271 | Theoretical and experimental determination of the effects governing the transannular Diels-Alder reaction of trans-trans-cis systems with or without activation of the dienophile. | A thorough study of the transannular Diels-Alder (TADA) reaction of trans-trans-cis macrocyclic trienes was carried out. It led to a better understanding of various parameters that govern the TADA reaction in particular and the Diels-Alder reaction in general. Thus, carbonyl activation of the dienophile and substitutio... |
11516268 | Cyclic homooligomers from sugar amino acids: synthesis, conformational analysis, and significance. | Sugar amino acids (SAAs) were designed as new building blocks carrying an amino group and a carboxyl group on a carbohydrate scaffold. By exploiting standard solid- and solution-phase coupling procedures, linear and cyclic homooligomers containing glucosyluronic acid methylamine (Gum) were synthesized. We achieved a hi... |
11514068 | Resistance of PC12 cells against nitric oxide (NO)-induced toxicity in long-term culture: implication of neuronal NO synthase expression. | We have previously reported that a nitric oxide (NO)-donor, (+/-)-(E)-4-ethyl-2-[(E)-hydroxyimino]-5-nitro-3-hexenamide (NOR3) induced cell death even at a low concentration in undifferentiated PC12 cells. In the present study, we found that PC12 cells which were cultured long-term for over 80 passages acquired resista... |
11514628 | Targeting of Shiga toxin B-subunit to retrograde transport route in association with detergent-resistant membranes. | In HeLa cells, Shiga toxin B-subunit is transported from the plasma membrane to the endoplasmic reticulum, via early endosomes and the Golgi apparatus, circumventing the late endocytic pathway. We describe here that in cells derived from human monocytes, i.e., macrophages and dendritic cells, the B-subunit was internal... |
11514627 | Amino acid substitutions of coiled-coil protein Tpr abrogate anchorage to the nuclear pore complex but not parallel, in-register homodimerization. | Tpr is a protein component of nuclear pore complex (NPC)-attached intranuclear filaments. Secondary structure predictions suggest a bipartite structure, with a large N-terminal domain dominated by heptad repeats (HRs) typical for coiled-coil--forming proteins. Proposed functions for Tpr have included roles as a homo- o... |
11514617 | Focal adhesion kinase and p130Cas mediate both sarcomeric organization and activation of genes associated with cardiac myocyte hypertrophy. | Hypertrophic terminally differentiated cardiac myocytes show increased sarcomeric organization and altered gene expression. Previously, we established a role for the nonreceptor tyrosine kinase Src in signaling cardiac myocyte hypertrophy. Here we report evidence that p130Cas (Cas) and focal adhesion kinase (FAK) regul... |
11514959 | Preoperative prediction of postoperative edema and effusion in pediatric cardiac surgery by altered antigen expression patterns on granulocytes and monocytes. | Postoperative edema and effusion (POEE) following cardiopulmonary bypass (CPB) surgery in children retards recovery and may aggravate postpericardiotomy (PPS), capillary leak syndrome (CLS), or multiorgan failure (MOF). Compared with complication-free children, POEE affected children have different preoperative serum l... |
11513573 | The gas-phase chemistry of cyclodextrin inclusion complexes. | Complexes of cyclodextrins with amino acid analytes are produced in the gas phase and are ideal for the study of molecular recognition. In this Account, we discuss the evidence for the presence of gas-phase inclusion complexes and the nature of the interaction. The use of cyclodextrins as chiral selectors in gas-phase ... |
11513392 | Leaching of 2,4-D from a soil in the presence of beta-cyclodextrin: laboratory columns experiments. | This study reports on the effect of the presence of beta-cyclodextrin (beta-CD) on the adsorption and mobility of the pesticide 2,4-dichlorophenoxyacetic acid (2,4-D) through soil columns. The previous application of beta-CD to the soil produced a retarded leaching of 2,4-D through the soil column, due probably to herb... |
11511242 | Supramolecular assistance to regioselectivity in the reactions of chlorocyclophosphazenes with sodium oxyanions: macrocyclic effect and anion dependence. | Comparative studies of the naphtholysis of crown-bearing tetrachlorocyclotriphosphazene 2 and its acyclic analogue, nongem-diethoxytetrachlorocyclotriphosphazene 5 (which was synthesized and isolated in the pure cis form for the purpose of this study), reveal a significant macrocyclic effect of the substituent on both ... |
11511237 | Synthesis, characterization, and optical response of dipolar and non-dipolar poly(phenylenevinylene) dendrimers. | New dipolar and non-dipolar poly(phenylenevinylene) dendrimers bearing electron-donating and electron-withdrawing groups have been efficiently synthesized using Heck and Horner-Wadsworth-Emmons reactions. The photoluminescence of these systems may be tuned in the blue zone by choosing the appropriate peripheral groups.... |
11511945 | Differential indication for mechanical circulatory support following heart transplantation. | <h4>Purpose</h4>We describe our experience with ventricular assist devices (VAD) in patients with cardiogenic shock refractory to pharmacological therapy and support using intraaortic balloon pump after cardiac transplantation.<h4>Patients</h4>Between July 1987 and August 1997, 848 patients underwent cardiac transplant... |
11511220 | Anion binding with two polyammonium macrocycles of different dimensionality. | A comparative study of the binding of nitrate and sulfate with a polyammonium monocycle L(1), (3,6,9,17,20,23-hexaazatricyclo[23.3.1.1(11,15)]-triaconta-1(29),11,13,15(30),25,27-hexaene), and the corollary bicycle L(2), (1,4,12,15,18,26,31,39-octaazapentacyclo-[13.13.13.1(6,10).1(20,24).1(33,37)]-tetratetraconta-6,7,9,... |
11510842 | Influence of structural variation in room-temperature ionic liquids on the selectivity and efficiency of competitive alkali metal salt extraction by a crown ether. | An improved method for the preparation of 1-alkyl-3-methylimidazolium hexafluorophosphates provides a series of room-temperature ionic liquids (RTILs) in which the 1-alkyl group is varied systematically from butyl to nonyl. For competitive solvent extraction of aqueous solutions of alkali metal chlorides with solutions... |
11506608 | Thermally responsive dendrons and dendrimers based on reversible furan-maleimide Diels-Alder adducts. | [reaction: see text]. Benzyl aryl ether dendrons and dendrimers containing thermally reversible furan-maleimide Diels-Alder adducts were prepared up to the third generation. The covalent cleavage and reassembly of the dendrons and dendrimers were evaluated by 1H NMR. |
11506599 | Synthesis of photo- and electroactive stilbenoid dendrimers carrying dibutylamino peripheral groups. | [structure: see text]. A novel convergent synthetic route for the preparation of functionalized and fluorescent stilbenoid dendrons built on the 1,3,5-benzene core and endowed with a periphery of dibutylamino groups has been developed. Long alkyl chains have been incorporated on the peripheral amino moieties to increas... |
11506596 | Synthesis and liquid membrane transport properties of photolabile molecular clips based on dithiane-spiro-crown ethers. | [reaction: see text]. Synthesis of novel dithiane-spiro-crown ethers starting from 5,5-di(hydroxymethyl)-1,3-dithiane is developed. These compounds can be used as building blocks to assemble photolabile bis-crown ethers via addition to dicarbonyl-containing tethers, e.g., isophthalic aldehyde. It is found that unlike t... |
11506567 | Polyphenylene dendrimers with different fluorescent chromophores asymmetrically distributed at the periphery. | A new synthetic approach leading to asymmetrically substituted polyphenylene dendrimers is presented. Following this method, polyphenylene dendrimers decorated with an increasing number of chromophores at the periphery have been obtained up to the second generation. Especially the synthesis of a polyphenylene dendrimer... |
11506032 | Effect of beta-cyclodextrin on the excited state proton transfer in 1-naphthol-2-sulfonate. | The photophysical properties of 1-naphthol-2-sulfonate (1-NOH-2-S) in various solvents and in aqueous beta-cyclodextrin (CD) solution have been investigated. The fluorescence quantum yields in non-aqueous solvents are approximately 0.5, while in water the fluorescence quantum yield is 0.1. The fluorescence quantum yiel... |
11506025 | Effects of cyclodextrins on the complexation between Methylene Blue and tetrakis(4-sulfonatophenyl)porphyrin in aqueous solutions. | In aqueous solutions buffered at pH 10.1, Methylene Blue (MB) forms a complex with tetrakis(4-sulfonatophenyl)porphyrin (TSPP). The equilibrium constant for the formation of the MB-TSPP complex has been evaluated to be 2.35 x 10(5) mol(-1) dm3 from the fluorescence quenching of MB by TSPP. Effects of alpha-, beta-, and... |
11504936 | Interchain hydrogen-bonding interactions may facilitate translocation of K+ ions across the potassium channel selectivity filter, as suggested by synthetic modeling chemistry. | A 4-fold symmetric arrangement of TVGYG polypeptides forms the selectivity filter of the K+ channel from Streptomyces lividans (KcsA). We report the synthesis and properties of synthetic models for the filter, p-tert-butyl-calix[4]arene-(OCH(2)CO-XOBz)(4) (X = V, VG, VGY), 1-3. The first cation (Na+, K+) binds to the f... |
11504893 | The hybridization-stabilization assay: a solution-based isothermal method for rapid screening and determination of sequence preference of ligands that bind to duplexed nucleic acids. | The gene-to-drug quest will be most directly served by the discovery and development of small molecules that bind to nucleic acids and modulate gene expression at the level of transcription and/or inhibit replication of infectious agents. Full realization of this potential will require implementation of a complete suit... |
11504874 | Standard atomic volumes in double-stranded DNA and packing in protein--DNA interfaces. | Standard volumes for atoms in double-stranded B-DNA are derived using high resolution crystal structures from the Nucleic Acid Database (NDB) and compared with corresponding values derived from crystal structures of small organic compounds in the Cambridge Structural Database (CSD). Two different methods are used to co... |
11502207 | A further clue to understanding the mobility of mitochondrial yeast cytochrome c: a (15)N T1rho investigation of the oxidized and reduced species. | A new approach was developed to overproduce 15N-enriched yeast iso-1-cytochrome c in the periplasm of Escherichia coli in order to perform a study of the motions in the ms-micros time scale on the oxidized and reduced forms through rotating frame 15N relaxation rates and proton/deuterium exchange studies. It is confirm... |
11502267 | Investigation of inclusion complexation of paclitaxel by cyclohenicosakis-(1-->2)-(beta-D-glucopyranosyl), by cyclic-(1-->2)-beta-D-glucans (cyclosophoraoses), and by cyclomaltoheptaoses (beta-cyclodextrins). | Inclusion complexation of the poorly soluble drug, paclitaxel, was investigated with various host cyclooligosaccharides such as a family of isolated neutral cyclohenicosakis-(1-->2)-(beta-D-glucopyranosyl) (cyclic-(1-->2)-beta-D-glucans, cyclosophoraoses), dimethyl cyclomaltoheptaose (cyclodextrins, DM-beta-CD) and hyd... |
11502175 | Human ferrochelatase: characterization of substrate-iron binding and proton-abstracting residues. | The terminal step in heme biosynthesis, the insertion of ferrous iron into protoporphyrin IX to form protoheme, is catalyzed by the enzyme ferrochelatase (EC 4.99.1.1). A number of highly conserved residues identified from the crystal structure of human ferrochelatase as being in the active site were examined by site-d... |
11502169 | Yeast mitochondrial dehydrogenases are associated in a supramolecular complex. | Separation of yeast mitochondrial complexes by colorless native polyacrylamide gel electrophoresis led to the identification of a supramolecular structure exhibiting NADH-dehydrogenase activity. Components of this complex were identified by N-terminal Edman degradation and matrix-assisted laser desorption ionization ma... |
11500385 | Human origin recognition complex binds to the region of the latent origin of DNA replication of Epstein-Barr virus. | Epstein-Barr virus (EBV) replicates in its latent phase once per cell cycle in proliferating B cells. The latent origin of DNA replication, oriP, supports replication and stable maintenance of the EBV genome. OriP comprises two essential elements: the dyad symmetry (DS) and the family of repeats (FR), both containing c... |
11500359 | New EMBO members' review: actin cytoskeleton regulation through modulation of PI(4,5)P(2) rafts. | The phosphoinositide lipid PI(4,5)P(2) is now established as a key cofactor in signaling to the actin cytoskeleton and in vesicle trafficking. PI(4,5)P(2) accumulates at membrane rafts and promotes local co-recruitment and activation of specific signaling components at the cell membrane. PI(4,5)P(2) rafts may thus be p... |
11499873 | Bone reinnervation after fracture: a study in the rat. | Reinnervation after tibial fracture in the rat was studied by analyzing the occurrence of growth-associated protein 43 (GAP-43), a marker for regenerating nerve fibers, and protein gene product 9.5 (PGP-9.5), a marker for mature nerve fibers, by immunohistochemistry. At 3 days postfracture, GAP-43--immunoreactive nerve... |
11499626 | Use of molecularly imprinted polymers in the solid-phase extraction of clenbuterol from animal feeds and biological matrices. | Clenbuterol molecularly imprinted polymers (MIPs) as chromatographic stationary phase for the solid-phase extraction (SPE) of the drug from biological samples have been prepared. Propylene columns filled with 500 mg of clenbuterol MIPs have been tested with respect to their loading capacity, memory effects, selectivity... |
11499479 | Determination of an arylether antiarrhythmic and its N-dealkyl metabolite in rat plasma and hepatic microsomal incubates using liquid chromatography-tandem mass spectrometry. | A method was developed and validated for the quantification of (+/-)-trans-[2-morpholino-1-(1-naphthalene-ethyloxy]cyclohexane monohydrochloride (RSD1070) and its N-dealkyl metabolite in rat plasma and hepatic microsomal incubates. Chromatographic separations were achieved using reversed-phase high-performance liquid c... |
11498035 | Why and how are peptide-lipid interactions utilized for self defence? | Animals defend themselves against invading pathogenic micro-organisms by utilizing cationic anti-microbial peptides, which rapidly kill various micro-organisms without exerting toxicity against the host. Physicochemical peptide-lipid interactions provide attractive mechanisms for innate immunity. Many of these peptides... |
11497996 | HMG1 and 2: architectural DNA-binding proteins. | HMG1 and 2 (high mobility group proteins 1 and 2; renamed HMGB1 and 2) contain two DNA-binding HMG-box domains (A and B) and a long acidic C-terminal domain. They bind DNA without sequence specificity, but have a high affinity for bent or distorted DNA, and bend linear DNA. The individual A and B boxes (which, although... |
11495585 | Fluorosulfonyl- and bis-(beta-chloroethyl)amino-phenylamino functionalized pyrazolo[4,3-e]1,2,4-triazolo[1,5-c]pyrimidine derivatives: irreversible antagonists at the human A3 adenosine receptor and molecular modeling studies. | A series of pyrazolotriazolopyrimidines was previously reported to be highly potent and selective human A(3) adenosine receptor antagonists (Baraldi et al. J. Med. Chem. 2000, 43, 4768-4780). A derivative having a methyl group at the N(8) pyrazole combined with a 4-methoxyphenylcarbamoyl moiety at N(5) position, displa... |
11495739 | The design of self-replicating helical peptides. | The self-assembly of helical peptides and information transfer through autocatalysis and cross-catalysis are the foundation of peptide-based molecular evolution models. Many fundamental properties of living systems, such as environmental sensitivity, chiroselectivity, cross-catalysis, dynamic error correction and condi... |
11495736 | Structures of lipid-DNA complexes: supramolecular assembly and gene delivery. | Recently, there has been a flurry of experimental work on understanding the supramolecular assemblies that are formed when cationic liposomes (CLs) are mixed with DNA. From a biomedical point of view, CLs (vesicles) are empirically known to be carriers of genes (sections of DNA) in nonviral gene delivery applications. ... |
11493006 | Mapping of binding sites for nidogens, fibulin-2, fibronectin and heparin to different IG modules of perlecan. | Perlecan, a major basement membrane proteoglycan, has a complex modular structure designed for the binding of many cellular and extracellular ligands. Its domain IV, which consists of a tandem of immunoglobulin-like modules (IG2-IG15), is rich in such binding sites, which have been mapped to different modules obtained ... |
11493004 | DNA cleavage reactions by type II restriction enzymes that require two copies of their recognition sites. | Several type II restriction endonucleases interact with two copies of their target sequence before they cleave DNA. Three such enzymes, NgoMIV, Cfr10I and NaeI, were tested on plasmids with one or two copies of their recognition sites, and on catenanes containing two interlinked rings of DNA with one site in each ring.... |
11493063 | High-frequency and field EPR investigation of (8,12-diethyl-2,3,7,13,17,18-hexamethylcorrolato)manganese(III). | High-field and frequency electron paramagnetic resonance (HFEPR) of solid (8,12-diethyl-2,3,7,13,17,18-hexamethylcorrolato)manganese(III), 1, shows that in the solid state it is well described as an S = 2 (high-spin) Mn(III) complex of a trianionic ligand, [Mn(III)C(3)(-)], just as Mn(III) porphyrins are described as [... |
11493062 | "Dip-Pen" nanolithography on semiconductor surfaces. | Dip-Pen Nanolithography (DPN) uses an AFM tip to deposit organic molecules through a meniscus onto an underlying substrate under ambient conditions. Thus far, the methodology has been developed exclusively for gold using alkyl or aryl thiols as inks. This study describes the first application of DPN to write organic pa... |
11493061 | Conformational gating of long distance electron transfer through wire-like bridges in donor-bridge-acceptor molecules. | A series of five donor-bridge-acceptor (DBA) molecules in which the donor is tetracene, the acceptor is pyromellitimide, and the bridge molecules are oligo-p-phenylenevinylenes (OPV) of increasing length has been shown to undergo electron transfer (ET) by means of two mechanisms. When the bridge is short, strongly dist... |
11493058 | Dynamics of an inclusion complex of chloroform and cryptophane-E: evidence for a strongly anisotropic van der Waals bond. | The motional dynamics of a van der Waals inclusion complex of cryptophane-E and chloroform has been investigated by a combined NMR exchange and relaxation study. The kinetics of exchange of chloroform between the bulk solution and the complex was investigated by means of proton EXSY measurements. The carbon-13 relaxati... |
11489296 | Investigation of the metabolism of substance P in rat striatum by microdialysis sampling and capillary electrophoresis with laser-induced fluorescence detection. | The metabolism of substance P (SP) was investigated in rat striatum using in vivo microdialysis. Substance P was perfused for 5 h at 0.2 microl/min, and its metabolism was followed for over 13 h. The resulting samples were derivatized precolumn with naphthalene-2,3-dicarboxaldehyde (NDA)/cyanide, separated and detected... |
11489946 | Phosphoinositide 3-kinase-dependent membrane recruitment of p62(dok) is essential for its negative effect on mitogen-activated protein (MAP) kinase activation. | A major pathway by which growth factors, such as platelet-derived growth factor (PDGF), regulate cell proliferation is via the receptor tyrosine kinase/Ras/mitogen-activated protein kinase (MAPK) signaling cascade. The output of this pathway is subjected to tight regulation of both positive and negative regulators. One... |
11489921 | High resolution mapping of mast cell membranes reveals primary and secondary domains of Fc(epsilon)RI and LAT. | In mast cells, cross-linking the high-affinity IgE receptor (Fc(epsilon)RI) initiates the Lyn-mediated phosphorylation of receptor ITAMs, forming phospho-ITAM binding sites for Syk. Previous immunogold labeling of membrane sheets showed that resting Fc(epsilon)RI colocalize loosely with Lyn, whereas cross-linked Fc(eps... |
11489551 | Cyclodextrins in topical drug formulations: theory and practice. | Cyclodextrins are cyclic oligosaccharides with a hydrophilic outer surface and a somewhat lipophilic central cavity. Cyclodextrins are able to form water-soluble inclusion complexes with many lipophilic water-insoluble drugs. In aqueous solutions drug molecules located in the central cavity are in a dynamic equilibrium... |
11488624 | Chloroplast biogenesis 84: solubilization and partial purification of membrane-bound [4-vinyl]chlorophyllide a reductase from etiolated barley leaves. | [4-Vinyl] chlorophyllide a reductase (4VCR) is a key enzyme of the chlorophyll (Chl) biosynthetic pathway. It catalyzes the conversion of divinyl chlorophyllide (Chlide) a to monovinyl Chlide a by reduction of the vinyl group at position 4 of the macrocycle to ethyl. 4VCR is a membrane-bound enzyme, embedded in etiopla... |
11487355 | Saccharinate as a versatile polyfunctional ligand. Four distinct coordination modes, misdirected valence, and a dominant aggregate structure from a single reaction system. | The reaction system consisting of copper, saccharinate, and the auxiliary ligands H(2)O, PPh(3), and NH(3) produces a sequence of compounds in which saccharinate is coordinated to copper in four distinct manners. The complex trans-[Cu(sacch)(2)(H(2)O)(4)] (2) (produced by thermal dehydration of trans-[Cu(sacch)(2)(H(2)... |
11487349 | Interaction of ferrocenoyl-dipeptides with 3-aminopyrazole derivatives: beta-sheet models? A synthetic, spectroscopic, structural, and electrochemical study. | The use of 3-aminopyrazole derivatives as beta-sheet templates is investigated using a series of ferrocenoyl (Fc)-dipeptides (Fc-Gly(2)-OEt, Fc-Ala(2)-OBzl, Fc-Leu-Phe-OMe, Fc-Val-Phe-OMe, Fc-Phe(2)-OMe, Fc-Leu(2)-OMe, Fc-Val(2)-OMe). The synthesis and full characterization are reported. The solid-state structures of F... |
11487341 | Crystal chemistry of the 4,4'-dimethyl-2,2'bipyridine/copper bromide system. | The reaction of 4,4'-dimethyl-2,2-bipyridine (henceforth dmbp) with copper(I) and/or copper(II) bromide under a wide variety of conditions has led to the isolation of 10 different crystalline materials. These include one Cu(I) salt, [Cu(dmbp)(2)]Br (a distorted tetrahedral Cu species and a lattice Br(-) ion); two mixed... |
11487337 | Chelators for radioimmunotherapy: I. NMR and ab initio calculation studies on 1,4,7,10-tetra(carboxyethyl)-1,4,7,10-tetraazacyclododecane (DO4Pr) and 1,4,7-tris(carboxymethyl)-10-(carboxyethyl)-1,4,7,10-tetraazacyclododecane (DO3A1Pr). | This work describes the modification of the chelating agent 1,4,7,10-tetraazacyclododecane-N,N',N' ',N' "-tetraacetic acid (DOTA) to improve the rate of metal loading for radioimmunotherapy applications. Previous ab initio calculations predicted that the compounds 1,4,7,10-tetra(carboxyethyl)-1,4,7,10-tetraazacyclodode... |
11487315 | Preparation, characterization, and luminescence properties of gallium-metal face-to-face diporphyrins (M = H(2), GaL, Ru(CO)(OH), Co). | The preparation and characterization of a new series of mixed metal cofacial anthracene-bridged diporphyrins (DPA) containing a GaL fragment (L = OMe, OH) and another metallic center (M = GaL, Ru(CO)(OH), Co, and H(2) (i.e. free base)) are reported. The luminescence properties at 298 and 77 K, in degassed EtOH solution... |
11485472 | Intramolecular AR--O--AR bond formation in calixarenes. | The formal dehydration of two vicinal phenol moieties of p-tert-butylcalix[6]arene was achieved in two steps by mild oxidation of the calixarene followed by treatment of the resulting monospirodienone derivative (9c) with an ionic hydrogenation mixture (Et(3)SiH/CF(3)COOH). Reaction of 9c yielded the unsubstituted xant... |
11485471 | ((15)N(5))-labeled adenine derivatives: synthesis and studies of tautomerism by (15)N NMR spectroscopy and theoretical calculations. | Since the nitrogens of nucleosides and nucleotides play an important role in the molecular recognition of these compounds, (15)N NMR became a method of choice in this field. Fully (15)N-labeled adenine, required in the latter studies, was obtained in four synthetic steps, in a good yield. Likewise, ((15)N(5))-2-hexylth... |
11485462 | Water-soluble adamantane-terminated dendrimers possessing a rhenium core. | A novel type of radiometal-containing dendrimer with potential radiotherapeutical applications is described. Different generations of this adamantane-terminated, Fréchet-type dendrimer (28, 29, 30), each consisting of two dendritic wedge ligands around a rhenium core, have been synthesized in organic solvent via reacti... |
11485568 | Kinetics of CO binding to the haem domain of murine inducible nitric oxide synthase: differential effects of haem domain ligands. | The binding of CO to the murine inducible nitric oxide synthase (iNOS) oxygenase domain has been studied by laser flash photolysis. The effect of the (6R)-5,6,7,8-tetrahydro-L-biopterin (BH(4)) cofactor L-arginine and several Type I L-arginine analogues/ligands on the rates of CO rebinding has been evaluated. The prese... |
11485554 | Apolipoprotein A-I stimulates the transport of intracellular cholesterol to cell-surface cholesterol-rich domains (caveolae). | We have studied the effect of lipid-free human plasma apolipoprotein A-I (apoA-I) on the transport of newly synthesized cholesterol to cell-surface cholesterol-rich domains, which in human skin fibroblasts are mainly represented by caveolae. Changes in transport of newly synthesized cholesterol were assessed after labe... |
11485173 | Elucidation of solution state complexation in wet-granulated oven-dried ibuprofen and beta-cyclodextrin: FT-IR and 1H-NMR studies. | The effect of oven-dried wet granulation on the complexation of beta-cyclodextrin with ibuprofen (IBU) in solution was investigated using Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (1H NMR), and molecular modeling. Granulation was carried out using 5 mL of three different granula... |
11485172 | Enhancement of ibuprofen dissolution via wet granulation with beta-cyclodextrin. | The purpose was to investigate the effect of wet granulation with beta-cyclodextrin (betaCD) on the enhancement of ibuprofen (IBU) dissolution. The effect of the granulation variables on the physical properties as well as the dissolution of tablets prepared from these granules was also examined. Granulation was perform... |
11483041 | Facile synthesis of rotaxanes through condensation reactions of DCC-[2]rotaxanes. | [reaction: see text] In this Letter, we present an easy method for the synthesis of rotaxanes using a novel DCC-[2]rotaxane. The DCC-[2]rotaxane is composed of dibenzo-24-crown-8 ether, an amino acid tether, and di-tert-butyl phenyl rings as blocking groups. It is relatively stable and can be purified by column chromat... |
11483030 | Solid-state supramolecular structures of resorcinol-arylboronic acid compounds. | [structure: see text] An X-ray crystallographic study of unique hydrogen-bonded supramolecular solid-state networks comprised of a tetraarylboronic acid resorcinarene is described. When 1 is recrystallized from 9:1 MeOH:EtOH, partial esterification takes place to give compound 2, the corresponding half methyl ester, wh... |
11483507 | Ergosterol is required for the Sec18/ATP-dependent priming step of homotypic vacuole fusion. | In vitro homotypic fusion of yeast vacuoles occurs in three stages: priming, the Sec18 (NSF)-mediated changes that precede vacuole association; docking, the Ypt7 and SNARE-mediated pairing of vacuoles; and fusion, mediated by calmodulin/V0/t-SNARE interactions. Defects in catalysts of each stage result in fragmented (u... |
11483498 | Structure and ligand recognition of the PB1 domain: a novel protein module binding to the PC motif. | PB1 domains are novel protein modules capable of binding to target proteins that contain PC motifs. We report here the NMR structure and ligand-binding site of the PB1 domain of the cell polarity establishment protein, Bem1p. In addition, we identify the topology of the PC motif-containing region of Cdc24p by NMR, anot... |
11480989 | Intramolecular energy hopping and energy trapping in polyphenylene dendrimers with multiple peryleneimide donor chromophores and a terryleneimide acceptor trap chromophore. | Intramolecular Förster-type excitation energy transfer (FRET) processes in a series of first-generation polyphenylene dendrimers substituted with spatially well-separated peryleneimide chromophores and a terryleneimide energy-trapping chromophore at the rim were investigated by steady-state and time-resolved fluorescen... |
11480974 | Self-assembly and anion encapsulation properties of cavitand-based coordination cages. | Two novel classes of cavitand-based coordination cages 7a--j and 8a--d have been synthesized via self-assembly procedures. The main factors controlling cage self-assembly (CSA) have been identified in (i) a P--M--P angle close to 90 degrees between the chelating ligand and the metal precursor, (ii) Pd and Pt as metal c... |
11480972 | Thermodynamic stabilities of linear and crinkled tapes and cyclic rosettes in melamine--cyanurate assemblies: a model description. | In this paper we describe model calculations for the self-assembly of N,N-disubstituted melamines 1 and N-substituted cyanuric acid or 5,5-disubstituted barbituric acid derivatives 2 into linear or crinkled tapes and cyclic rosettes via cooperative hydrogen bond formation. The model description considers all possible s... |
11479367 | Molecular recognition by induced fit: how fit is the concept? | Induced fit explains why biomolecules can bind together even if they are not optimized for binding. However, induced fit can lead to a kinetic bottleneck and does not describe every interaction in the absence of prior complementarity. Preselection of a fitting conformer is an alternative to induced fit. |
11478902 | Stability and function of interdomain linker variants of glucoamylase 1 from Aspergillus niger. | Several variants of glucoamylase 1 (GA1) from Aspergillus niger were created in which the highly O-glycosylated peptide (aa 468--508) connecting the (alpha/alpha)(6)-barrel catalytic domain and the starch binding domain was substituted at the gene level by equivalent segments of glucoamylases from Hormoconis resinae, H... |
11478875 | Identification of a subunit interface in transthyretin amyloid fibrils: evidence for self-assembly from oligomeric building blocks. | Amyloid and prion diseases appear to stem from the conversion of normally folded proteins into insoluble, fiber-like assemblies. Despite numerous structural studies, a detailed molecular characterization of amyloid fibrils remains elusive. In particular, models of amyloid fibrils proposed thus far have not adequately d... |
11472217 | Design, synthesis, and structure-activity relationships of macrocyclic hydroxamic acids that inhibit tumor necrosis factor alpha release in vitro and in vivo. | To search for TNF-alpha (tumor necrosis factor alpha) converting enzyme (TACE) inhibitors, we designed a new class of macrocyclic hydroxamic acids by linking the P1 and P2' residues of acyclic anti-succinate-based hydroxamic acids. A variety of residues including amide, carbamate, alkyl, sulfonamido, Boc-amino, and ami... |
11472812 | Polysaccharides in colon-specific drug delivery. | Natural polysaccharides are now extensively used for the development of solid dosage forms for delivery of drug to the colon. The rationale for the development of a polysaccharide based delivery system for colon is the presence of large amounts of polysaccharidases in the human colon as the colon is inhabited by a larg... |
11472901 | Biotransformation of various substituted aromatic compounds to chiral dihydrodihydroxy derivatives. | The biotransformation of four different classes of aromatic compounds by the Escherichia coli strain DH5alpha(pTCB 144), which contained the chlorobenzene dioxygenase (CDO) from Pseudomonas sp. strain P51, was examined. CDO oxidized biphenyl as well as monochlorobiphenyls to the corresponding cis-2,3-dihydro-2,3-dihydr... |
11470609 | Polymers in drug delivery. | Advances in polymer science have led to the development of several novel drug-delivery systems. A proper consideration of surface and bulk properties can aid in the designing of polymers for various drug-delivery applications. Biodegradable polymers find widespread use in drug delivery as they can be degraded to non-to... |
11468361 | Molecular mimicry of substrate oxygen atoms by water molecules in the beta-amylase active site. | Soybean beta-amylase (EC 3.2.1.2) has been crystallized both free and complexed with a variety of ligands. Four water molecules in the free-enzyme catalytic cleft form a multihydrogen-bond network with eight strategic residues involved in enzyme-ligand hydrogen bonds. We show here that the positions of these four water... |
11466430 | Interactions between fibroblast growth factors and Notch regulate neuronal differentiation. | The differentiation of precursor cells into neurons has been shown to be influenced by both the Notch signaling pathway and growth factor stimulation. In this study, the regulation of neuronal differentiation by these mechanisms was examined in the embryonic day 10 neuroepithelial precursor (NEP) population. By downreg... |
11466771 | Chiral recognition of dipeptide methyl esters by an anionic beta-cyclodextrin. | Chiral recognition of dipeptide methyl esters by anionic heptakis[6-carboxymethylthio-6-deoxy]-beta-cyclodextrin (per-CO(2)(-)-beta-CD) was studied in D(2)O at pD 7.0 by means of (1)H NMR spectroscopy. The methyl esters of alanylalanine (Ala-Ala-OMe), alanylleucine (Ala-Leu-OMe), alanyltryptophan (Ala-Trp-OMe), glycylt... |
11466769 | Carbohydrate-derived alkylcobalt carbonyl:([(1,2:5,6-di-O,O-isopropylidene-alpha-D-glucofuranos-3-yl)oxycarbonyl]methyl)cobalt tricarbonyl triphenylphosphene. | A carbohydrate-derivative alkylcobalt carbonyl,([(1,2:5,6-di-O,O-isopropylidene-alpha-D-glucofuranos-3-yl)oxycarbonyl]methyl)cobalt tricarbonyl triphenylphosphene(3) was prepared and characterized by IR, NMR, and CD spectra, as well as by X-ray diffraction. The supramolecular chemistry in the crystalline P2(1)2(1)2(1) ... |
11466768 | Enantiomer separation of hydrocarbons in preparation for ROSETTA's "chirality-experiment". | Until now the favored method for separating racemic pairs of underivatized alcohols, diols, and phenylsubstituted amines has been gas chromatography on cyclodextrin phases. However, certain enantiomers of saturated chiral hydrocarbons could not be resolved in this way because they lack the functional groups necessary t... |
11463823 | Polynucleotide phosphorylase functions as both an exonuclease and a poly(A) polymerase in spinach chloroplasts. | The molecular mechanism of mRNA degradation in the chloroplast consists of sequential events including endonucleolytic cleavage, the addition of poly(A)-rich sequences to the endonucleolytic cleavage products, and exonucleolytic degradation by polynucleotide phosphorylase (PNPase). In Escherichia coli, polyadenylation ... |
11463655 | Spectral inhomogeneity of photosystem I and its influence on excitation equilibration and trapping in the cyanobacterium Synechocystis sp. PCC6803 at 77 K. | Ultrafast transient absorption spectroscopy was used to probe excitation energy transfer and trapping at 77 K in the photosystem I (PSI) core antenna from the cyanobacterium Synechocystis sp. PCC 6803. Excitation of the bulk antenna at 670 and 680 nm induces a subpicosecond energy transfer process that populates the Ch... |
11463622 | Free energy decomposition of protein-protein interactions. | A free energy decomposition scheme has been developed and tested on antibody-antigen and protease-inhibitor binding for which accurate experimental structures were available for both free and bound proteins. Using the x-ray coordinates of the free and bound proteins, the absolute binding free energy was computed assumi... |
11463614 | Polymer-induced membrane contraction, phase separation, and fusion via Marangoni flow. | Experiments have shown that the depletion of polymer in the region between two apposed (contacting or nearly contacting) bilayer membranes leads to fusion. In this paper we show theoretically that the addition of nonadsorbing polymer in solution can promote lateral contraction and phase separation of the lipids in the ... |
11462029 | Inhibition of p53 tumor suppressor by viral interferon regulatory factor. | The irreversible cell cycle arrest and apoptosis induced by p53 are part of the host surveillance mechanisms for viral infection and tumor induction. Kaposi's sarcoma-associated herpesvirus (KSHV), the most recently discovered human tumor virus, is associated with the pathogenesis of Kaposi's sarcoma, primary effusion ... |
11462020 | Human parainfluenza virus type 3 HN-receptor interaction: effect of 4-guanidino-Neu5Ac2en on a neuraminidase-deficient variant. | The envelope of human parainfluenza virus type 3 (HPF3) contains two viral glycoproteins, the hemagglutinin-neuraminidase (HN) and the fusion protein (F). HN, which is responsible for receptor attachment and for promoting F-mediated fusion, also possesses neuraminidase (receptor-destroying) activity. We reported previo... |
11462007 | Characterization of new syncytium-inhibiting monoclonal antibodies implicates lipid rafts in human T-cell leukemia virus type 1 syncytium formation. | We have previously shown that erythroleukemia cells (K562) transfected with vascular adhesion molecule 1 (VCAM-1) are susceptible to human T-cell leukemia virus type 1 (HTLV-1)-induced syncytium formation. Since expression of VCAM-1 alone is not sufficient to render cells susceptible to HTLV-1 fusion, K562 cells appear... |
11462004 | Simian virus 40 Vp1 DNA-binding domain is functionally separable from the overlapping nuclear localization signal and is required for effective virion formation and full viability. | A DNA-binding domain (DBD) was identified on simian virus 40 (SV40) major capsid protein Vp1, and the domain's function in the SV40 life cycle was examined. The DBD was mapped by assaying various recombinant Vp1 proteins for DNA binding in vitro. The carboxy-terminal 58-residue truncated Vp1DeltaC58 pentamer bound DNA ... |
11461995 | A virally encoded chaperone specialized for folding of the major capsid protein of African swine fever virus. | It is generally believed that cellular chaperones facilitate the folding of virus capsid proteins, or that capsid proteins fold spontaneously. Here we show that p73, the major capsid protein of African swine fever virus (ASFV) failed to fold and aggregated when expressed alone in cells. This demonstrated that cellular ... |
11455610 | A new method to model membrane protein structure based on silent amino acid substitutions. | The importance of accurately modeling membrane proteins cannot be overstated, in lieu of the difficulties in solving their structures experimentally. Often, however, modeling procedures (e.g., global searching molecular dynamics) generate several possible candidates rather then pointing to a single model. Herein we pre... |
11454802 | Arginine induced acute pancreatitis alters the actin cytoskeleton and increases heat shock protein expression in rat pancreatic acinar cells. | Arginine induced acute pancreatitis was evaluated as a novel and distinct form of experimental pancreatitis with particular attention to the actin cytoskeleton and expression of heat shock or stress proteins. Arginine induced a dose related necrotising pancreatitis in rats, as shown by histological evaluation, and an i... |
11443082 | Identification, cloning, expression, and characterization of the extracellular acarbose-modifying glycosyltransferase, AcbD, from Actinoplanes sp. strain SE50. | An extracellular enzyme activity in the culture supernatant of the acarbose producer Actinoplanes sp. strain SE50 catalyzes the transfer of the acarviosyl moiety of acarbose to malto-oligosaccharides. This acarviosyl transferase (ATase) is encoded by a gene, acbD, in the putative biosynthetic gene cluster for the alpha... |
11438678 | Drosophila Med6 is required for elevated expression of a large but distinct set of developmentally regulated genes. | Mediator is the evolutionarily conserved coactivator required for the integration and recruitment of diverse regulatory signals to basal transcription machinery. To elucidate the functions of metazoan Mediator, we isolated Drosophila melanogaster Med6 mutants. dMed6 is essential for viability and/or proliferation of mo... |
11438677 | Recognition of RNA branch point sequences by the KH domain of splicing factor 1 (mammalian branch point binding protein) in a splicing factor complex. | Mammalian splicing factor 1 (SF1; also mammalian branch point binding protein [mBBP]; hereafter SF1/mBBP) specifically recognizes the seven-nucleotide branch point sequence (BPS) located at 3' splice sites and participates in the assembly of early spliceosomal complexes. SF1/mBBP utilizes a "maxi-K homology" (maxi-KH) ... |
11435605 | Adenovirus type 9 fiber knob binds to the coxsackie B virus-adenovirus receptor (CAR) with lower affinity than fiber knobs of other CAR-binding adenovirus serotypes. | The coxsackie B virus and adenovirus (Ad) receptor (CAR) functions as an attachment receptor for multiple Ad serotypes. Here we show that the Ad serotype 9 (Ad9) fiber knob binds to CAR with much reduced affinity compared to the binding by Ad5 and Ad12 fiber knobs as well as the knob of the long fiber of Ad41 (Ad41L). ... |
11435598 | Lipid rafts and pseudotyping. | Specific interactions between envelope and core proteins govern the membrane assembly of most enveloped viruses. Despite this, mixed infections lead to pseudotyping, the association of the viral cores of one virus with the envelopes of another. How does this occur? We show here that the detergent-insoluble lipid rafts ... |
11435594 | Functional analysis of adenovirus protein IX identifies domains involved in capsid stability, transcriptional activity, and nuclear reorganization. | The product of adenovirus (Ad) type 5 gene IX (pIX) is known to actively participate in the stability of the viral icosahedron, acting as a capsid cement. We have previously demonstrated that pIX is also a transcriptional activator of several viral and cellular TATA-containing promoters, likely contributing to the tran... |
11435583 | Therapeutic effect of a Gag-nuclease fusion protein against retroviral infection in vivo. | Recently, remarkable progress has been made in developing effective combination drug therapies that can control but not cure retroviral replication. Even when effective, these drug regimens are toxic, they require demanding administration schedules, and resistant viruses can emerge. Thus the need for new gene-based the... |
11435581 | Minute virus of mice initiator protein NS1 and a host KDWK family transcription factor must form a precise ternary complex with origin DNA for nicking to occur. | Parvoviral rolling hairpin replication generates palindromic genomic concatemers whose junctions are resolved to give unit-length genomes by a process involving DNA replication initiated at origins derived from each viral telomere. The left-end origin of minute virus of mice (MVM), oriL, contains binding sites for the ... |
11435574 | Selective regulation of human immunodeficiency virus-infected CD4(+) lymphocytes by a synthetic immunomodulator leads to potent virus suppression in vitro and in hu-PBL-SCID mice. | We have previously observed that the synthetic immunomodulator Murabutide inhibits human immunodeficiency virus type 1 (HIV-1) replication at multiple levels in macrophages and dendritic cells. The present study was designed to profile the activity of Murabutide on CD8-depleted phytohemagglutinin-activated lymphocytes ... |
11429179 | Treatment with beta-cyclodextrin of natural Cryptosporidium parvum infections in lambs under field conditions. | Following the unexpected activity of the excipient beta-cyclodextrin against experimental infection by Cryptosporidium parvum in suckling mice, its efficacy in the prevention and treatment of natural infections in lambs was evaluated under field conditions. Fifty-three crossbred neonatal lambs were randomly selected fo... |
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