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15161287 | A controlled supramolecular approach toward cation-specific chemosensors: alkaline earth metal ion-driven exciton signaling in squaraine tethered podands. | Three different squaraine tethered bichromophoric podands 3a-c with one, two, and three oxygen atoms in the podand chain and an analogous monochromophore 4a were synthesized and characterized. Among these, the bichromophores 3a-c showed high selectivity toward alkaline earth metal cations, particularly to Mg(2+) and Ca... |
15161283 | In situ gamma ray-initiated polymerization to stabilize surface micelles. | Surfactant molecules containing hydrophobic long alkyl chains and hydrophilic groups can organize into various micellar structures both in bulk solution and at interface. However, because of the dynamical nature of surfactant micelles, efforts directed at fixing their structures in bulk solution by polymerization have ... |
15161267 | Electron conduction across electrode-immobilized neutravidin bound with biotin-labeled ruthenium pentaamine. | Voltammetry is reported here of a self-assembled redox-protein conjugate consisting of neutravidin conjugated with a biotin derivative redox probe, Ru(NH3)5(N-[(N-[(4-pyridyl)methyl]biotinamide], immobilized on gold electrodes modified by self-assembled monolayers of mercaptoundecanoic acid. This voltammetry indicates ... |
15161257 | A quantum dot conjugated sugar ball and its cellular uptake. On the size effects of endocytosis in the subviral region. | The lipophilic CdSe quantum dot (QD) coated with trioctylphosphine oxide (TOPOQD) can be extracted from chloroform into water upon interaction with macrocyclic glycocluster amphiphile 1. The QD-conjugated and highly fluorescent sugar ball of a size of 15 nm (TOPOQD1) thus solubilized in water readily invades Hela cells... |
15161638 | Keratinocytes from patients lacking collagen XVII display a migratory phenotype. | Acquired or inherited junctional epidermolysis bullosa are skin diseases characterized by a separation between the epidermis and the dermis. In inherited nonlethal junctional epidermolysis bullosa, genetic analysis has identified mutations in the COL17A1 gene coding for the transmembrane collagen XVII whereas patients ... |
15159064 | A role for lipid rafts in C1q-triggered O2- generation by human neutrophils. | Calreticulin, a candidate C1q receptor, was shown recently to be present on the surface of human neutrophils in association with glycosylphosphatidylinositol (GPI) anchored proteins, particularly CD59. In this study, we show that antibodies to CD59, as well as to every other GPI-anchored protein tested, inhibited the C... |
15157194 | Using microscopic techniques to reveal the mechanism of anion exchange in crystalline co-ordination polymers. | Co-ordination polymers are currently attracting extensive interest due to their potential applications as supramolecular hosts, vessels, and frameworks for storage and separations. Many applications rely on the ion exchange capabilities of these compounds, and considerable debate surrounds the mechanism by which ion ex... |
15158961 | A novel spray-drying technique to produce low density particles for pulmonary delivery. | To date, all marketed DPI products rely on jet-milled, micronized drugs. Micronization often leads to drug powders exhibiting a large hydrophobic surface area resulting in strong cohesive forces, agglomeration and unsuitable aerosolization properties. In the current study, a new approach to prepare low density drug par... |
15158952 | Evaluation of new propofol aqueous solutions for intravenous anesthesia. | The aim of this study was to evaluate the potential of using three new aqueous formulations of propofol for intravenous (i.v.) anesthesia. The first formulation can be prepared by using hydroxypropyl-gamma-cyclodextrin (HP-gamma-CD) as a solubilizer. Phase-solubility analysis showed a linear increase in the solubility ... |
15157082 | Assembly of an active group II intron-maturase complex by protein dimerization. | Group II intron-encoded proteins promote both splicing and mobility of the intron RNA through formation of a specific RNA-protein complex. The Lactococcus lactis L1.LtrB intron encodes a maturase, LtrA, with reverse transcriptase homology and specific binding affinity for two domains of the intron RNA. The catalyticall... |
15155678 | Induction of de novo subcortical actin filament assembly by Treponema denticola major outer sheath protein. | Treponema denticola and its major outer sheath protein (Msp) induce actin reorganization in fibroblasts. We adapted a barbed-end labeling/imaging assay to monitor Msp-induced subcortical actin filament assembly in neutrophils and fibroblasts. Msp, at an actin-reorganizing concentration, inhibited migration of these dis... |
15155657 | The novel fibrinogen-binding protein FbsB promotes Streptococcus agalactiae invasion into epithelial cells. | Streptococcus agalactiae is a major cause of bacterial sepsis and meningitis in human newborns. The interaction of S. agalactiae with host proteins and the entry into host cells thereby represent important virulence traits of these bacteria. The present report describes the identification of the fbsB gene, encoding a n... |
15155653 | Role of transferrin receptor from a Neisseria meningitidis tbpB isotype II strain in human transferrin binding and virulence. | Neisseria meningitidis acquires iron through the action of the transferrin (Tf) receptor, which is composed of the Tf-binding proteins A and B (TbpA and TbpB). Meningococci can be classified into isotype I and II strains depending on whether they harbor a type I or II form of TbpB. Both types of TbpB have been shown to... |
15155629 | Binding and internalization of Clostridium perfringens iota-toxin in lipid rafts. | Clostridium perfringens iota-toxin is a binary toxin composed of an enzymatic component (Ia) and a binding component (Ib). The oligomer of Ib formed in membranes induces endocytosis. We examined the binding and internalization of Ib by using Cy3-labeled Ib. Labeled Ib was retained at the membranes of MDCK cells for 60 ... |
15155615 | Borrelia burgdorferi binds to, invades, and colonizes native type I collagen lattices. | Borrelia burgdorferi binds strongly to the extracellular matrix and cells of the connective tissue, a binding apparently mediated by specific proteins and proteoglycans. We investigated the interactions between B. burgdorferi cells and intact type I collagen using hydrated lattices that reproduce features of in vivo co... |
15025560 | Increased levels of insulin and insulin-like growth factor-1 hybrid receptors and decreased glycosylation of the insulin receptor alpha- and beta-subunits in scrapie-infected neuroblastoma N2a cells. | We have previously shown that ScN2a cells (scrapie-infected neuroblastoma N2a cells) express 2-fold- and 4-fold-increased levels of IR (insulin receptor) and IGF-1R (insulin-like growth factor-1 receptor) respectively. In addition, the IR alpha- and beta-subunits are aberrantly processed, with apparent molecular masses... |
15155234 | In vitro activity of OPT-80 against Clostridium difficile. | Clostridium difficile remains the major cause of nosocomial diarrhea. Reports on impaired susceptibility of C. difficile to metronidazole and vancomycin and frequent relapses of patients after therapy necessitate the search for new substances. With this study, the activity of OPT-80, a new macrocycle, against 207 C. di... |
15155230 | Mutations conferring resistance to a potent hepatitis C virus serine protease inhibitor in vitro. | BILN 2061 is a novel, specific hepatitis C virus (HCV) NS3 serine protease inhibitor discovered by Boehringer Ingelheim that has shown potent activity against HCV replicons in tissue culture and is currently under clinical investigation for the treatment of HCV infection. The poor fidelity of the HCV RNA-dependent RNA ... |
15155221 | Structure and association of human lactoferrin peptides with Escherichia coli lipopolysaccharide. | An 11-amino-acid amphipathic synthetic peptide homologous to a helical region on helix 1 of human lactoferrin HLP-2 exhibited bactericidal activity against Escherichia coli serotype O111, whereas an analogue synthesized with Pro substituted for Met, HLP-6, had greatly reduced antimicrobial activity. The bactericidal ac... |
15149719 | Low-voltage electron microscopy of polymer and organic molecular thin films. | We have demonstrated the capabilities of a novel low-voltage electron microscope (LVEM) for imaging polymer and organic molecular thin films. The LVEM can operate in transmission electron microscopy, scanning transmission electron microscopy, scanning electron microscopy, and electron diffraction modes. The microscope ... |
15150246 | Recognition of ferric catecholates by FepA. | Escherichia coli FepA transports certain catecholate ferric siderophores, but not others, nor any noncatecholate compounds. Direct binding and competition experiments demonstrated that this selectivity originates during the adsorption stage. The synthetic tricatecholate Fe-TRENCAM bound to FepA with 50- to 100-fold-low... |
15150223 | Stress response gene regulation in Chlamydia is dependent on HrcA-CIRCE interactions. | HrcA is a transcriptional repressor that regulates stress response genes in many bacteria by binding to the CIRCE operator. We have previously shown that HrcA regulates the promoter for the dnaK heat shock operon in Chlamydia. Here we demonstrate that HrcA represses a second heat shock promoter that controls the expres... |
15149865 | Impact of cholesterol depletion on shape changes, actin reorganization, and signal transduction in neutrophil-like HL-60 cells. | Stimulation of neutrophils with chemotactic peptide induces actin reorganization, formation of actin-rich protrusions, and development of polarity. Shape changes and actin polymerization can also be induced by phorbol ester-mediated direct activation of protein kinase C (PKC). We have investigated the role of cholester... |
15147845 | Recognition of functional sites in protein structures. | Recognition of regions on the surface of one protein, that are similar to a binding site of another is crucial for the prediction of molecular interactions and for functional classifications. We first describe a novel method, SiteEngine, that assumes no sequence or fold similarities and is able to recognize proteins th... |
15147567 | Sequence-specific binding of normal serum immunoglobulin M to exposed protein C-termini. | Both the timely clearance of degraded endogenous structures and the presence of secreted natural immunoglobulin M (IgM) are needed to avoid autoimmunity. These requirements may be causally related provided that natural IgM preferentially reacts with degraded antigens and, by activating complement, mediates their non-in... |
15146081 | Secondary structure models of the 3' untranslated regions of diverse R2 RNAs. | The RNA structure of the 3' untranslated region (UTR) of the R2 retrotransposable element is recognized by the R2-encoded reverse transcriptase in a reaction called target primed reverse transcription (TPRT). To provide insight into structure-function relationships important for TPRT, we have created alignments that re... |
15140999 | Human immunodeficiency virus type 1 Gag contains a dileucine-like motif that regulates association with multivesicular bodies. | Multivesicular bodies (MVBs) are cholesterol-enriched organelles formed by the endocytic pathway. The topology of vesicle formation in MVBs is identical to that of retroviral budding from the plasma membrane, and budding of human immunodeficiency virus type 1 (HIV-1) into MVBs in macrophages has recently been visualize... |
15140958 | T-cell epitopes in severe acute respiratory syndrome (SARS) coronavirus spike protein elicit a specific T-cell immune response in patients who recover from SARS. | The immunogenicity of HLA-A2-restricted T-cell epitopes in the S protein of the Severe acute respiratory syndrome coronavirus (SARS-CoV) and of human coronavirus strain 229e (HCoV-229e) was analyzed for the elicitation of a T-cell immune response in donors who had fully recovered from SARS-CoV infection. We employed on... |
15140957 | Parvovirus infection of cells by using variants of the feline transferrin receptor altering clathrin-mediated endocytosis, membrane domain localization, and capsid-binding domains. | The feline and canine transferrin receptors (TfRs) bind canine parvovirus to host cells and mediate rapid capsid uptake and infection. The TfR and its ligand transferrin have well-described pathways of endocytosis and recycling. Here we tested several receptor-dependent steps in infection for their role in virus infect... |
15140447 | A suite of 3D NMR methods for characterizing complex hydrocarbon structure fragments. | A suite of triple resonance 3D NMR experiments is presented for the complete connectivity assignment of the hydrocarbon network in complex macromolecular and supramolecular organic structures. These new 3D NMR methods rely only on the presence of a unique set of (13)C resonances (from (13)C(X)) which are separated from... |
15140440 | Wavelet-based ultra-high compression of multidimensional NMR data sets. | The application of a lossy data compression algorithm based on wavelet transform to 2D NMR spectra is presented. We show that this algorithm affords rapid and extreme compression ratios (e.g., 800:1), providing high quality reconstructed 2D spectra. The algorithm was evaluated to ensure that qualitative and quantitativ... |
15140767 | Appropriate and effective management of rheumatoid arthritis. | Early referral (at <3 months) and early DMARD treatment enable the course of RA to be changed. Once the disease has become aggressive it is much harder to treat and improvements will not be as great as they would have been with earlier treatment. The latest strategies and treatments enable remission to be achieved in m... |
15139024 | P2X3 receptor localizes into lipid rafts in neuronal cells. | P2X receptors are a family of seven (P2X(1-7)) cation channels gated by extracellular ATP, widely expressed in neurons and nonneuronal cells. Lipid rafts are cholesterol/sphingolipid-rich membrane domains, involved in many cellular processes, including transmembrane receptor signaling, vesicle traffic, and protein sort... |
15130537 | Improved antiviral activity in vitro of ribavirin against measles virus after complexation with cyclodextrins. | Despite vaccination, measles remains a burden in both developed and developing countries and complications may necessitate an efficient therapy. Measles virus (MEV) is susceptible to ribavirin (RBV), but the use of this drug is limited by its toxicity. Cyclodextrins (CDs) can form complexes with numerous molecules, imp... |
15120294 | Surfactant-encapsulated polyoxometalloeuropate: polarized Eu3+ emission in the highly ordered self-organizing film. | An organic/inorganic composite, (DODA)(9)EuW(10)O(36).9H(2)O, can form a highly ordered self-organizing film with a layered structure and almost fully interdigitated alkyl chains at solid supports. EuW10O36(9-) is deduced to be oriented in its self-organizing film, resulting in its polarized emission, which offers an a... |
15120276 | Synthesis and characterization of tri(ethylene oxide)-attached poly(amidoamine) dendrimer layers on gold. | This paper describes the synthesis of a tri(ethylene oxide)-attached fourth-generation poly(amidoamine) dendrimer (EO3-dendrimer) and the characterization of its layers on gold. NMR analysis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry revealed that about 61 amine groups of a G4 PAMA... |
15120272 | Formation and stability of rare earth metalloporphyrin monolayer films on amino-terminated silanized quartz surfaces studied by ultraviolet-visible and X-ray photoelectron spectroscopy. | We investigated the fabrication of self-assembled monolayers of 5,10,15,20-tetra-(p-chlorophenyl)-porphyrin metal hydroxyl compounds (MOH; M=Gd, Tb, Er, Lu) on amino-terminated silanized quartz surfaces using ultraviolet-visible (UV-vis) and X-ray photoelectron spectroscopy (XPS). The orientation of MOH molecules in th... |
18007450 | Synthesis and characterisation of macrocyclic diamino chiral crown ethers. | A benign and efficient synthesis of chiral macrocyclic 'aza-crown' ethers of varying ring size is reported. The synthesis involves a Schiff base condensation of ether linked dialdehydes of varying chain length and (1R,2R)-(-)-1,2-diaminocyclohexane under mild conditions to yield the macrocycles, which are subsequently ... |
18007443 | Nitrogen heterocycles as building blocks for new metallosupramolecular architectures. | The syntheses of representative examples of five classes of new heterocyclic ligands are described. These include N,N'-chelating bis-heterocycles, binucleating ligands, cyclometallated compounds, chiral ligands and a family of polyheteroaryl-linked arenes. |
15178853 | catena-Poly[[aqua(2,2'-bipyridine-kappa2N,N')manganese(II)]-mu-terephthalato-kappa3O,O':O"]. | The title complex, [Mn(C(8)H(4)O(4))(C(10)H(8)N(2))(H(2)O)](n), takes the form of a zigzag chain, with the terephthalate dianion (tp) acting as a tridentate ligand. The Mn(II) center is surrounded by two tp ligands, one water molecule and one 2,2'-bipyridine (bipy) ligand and exhibits a severely distorted octahedral co... |
15178851 | Bis(mu-1,10-phenanthrolin-2-olato-kappa3N,N':O)dicopper(I)(Cu-Cu) monohydrate. | The crystal structure of the title compound, [Cu(2)(C(12)H(7)N(2)O)(2)].H(2)O, shows that this dinuclear complex has shorter Cu-N, Cu-O and Cu-Cu distances within the coordination sphere than similar reported complexes. The complex molecule is located on a centre of symmetry and the water molecule is on a twofold axis ... |
15169869 | Lipid raft-dependent glucagon-like peptide-2 receptor trafficking occurs independently of agonist-induced desensitization. | The intestinotrophic and cytoprotective actions of glucagon-like peptide-2 (GLP-2) are mediated by the GLP-2 receptor (GLP-2R), a member of the class II glucagon-secretin G protein-coupled receptor superfamily. Although native GLP-2 exhibits a short circulating half-life, long-acting degradation-resistant GLP-2 analogu... |
15249947 | Tren centered tris-macrocycles as polytopic ligands for Cu(II) and Ni(II). | Two novel symmetric polytopic ligands L(1) and L(2) have been synthesized. They are composed of three 1,4,8,11-tetraazacyclotetradecane macrocycles which are connected to a central tren moiety via an ethylene and a trimethylene bridge, respectively. The complexation potential and the speciation diagrams of L(1) and L(2... |
15169956 | Affinity transfer by CDR grafting on a nonimmunoglobulin scaffold. | Neocarzinostatin (NCS) is a small "all beta" protein displaying the same overall fold as immunoglobulins. This protein possesses a well-defined hydrophobic core and two loops structurally equivalent to the CDR1 and CDR3 of immunoglobulins. NCS is the most studied member of the enediynechromoprotein family, and is clini... |
15216332 | Self-assembly of aluminium-salen coupled nanostructures from encoded modules with cleavable disulfide DNA-linkers. | DNA-directed coupling of organic modules by formation of stable aluminium-salen complexes, makes possible the subsequent reductive cleavage of disulfide linkers and release of the two oligonucleotide chains attached to each building-block. |
15167891 | Fast, DNA-sequence independent translocation by FtsK in a single-molecule experiment. | Escherichia coli FtsK is an essential cell division protein, which is thought to pump chromosomal DNA through the closing septum in an oriented manner by following DNA sequence polarity. Here, we perform single-molecule measurements of translocation by FtsK50C, a derivative that functions as a DNA translocase in vitro.... |
15166287 | Ferritin reactions: direct identification of the site for the diferric peroxide reaction intermediate. | Ferritins managing iron-oxygen biochemistry in animals, plants, and microorganisms belong to the diiron carboxylate protein family and concentrate iron as ferric oxide approximately 10(14) times above the ferric K(s). Ferritin iron (up to 4,500 atoms), used for iron cofactors and heme, or to trap DNA-damaging oxidants ... |
15186492 | START lipid/sterol-binding domains are amplified in plants and are predominantly associated with homeodomain transcription factors. | <h4>Background</h4>In animals, steroid hormones regulate gene expression by binding to nuclear receptors. Plants lack genes for nuclear receptors, yet genetic evidence from Arabidopsis suggests developmental roles for lipids/sterols analogous to those in animals. In contrast to nuclear receptors, the lipid/sterol-bindi... |
15168086 | Targeting of tumor cells by lymphocytes engineered to express chimeric receptor genes. | Adoptive cellular immunotherapy of cancer has been limited to date mostly due to the poor immunogenicity of tumor cells, the immunocompromised status of cancer patients in advanced stages of their disease, and difficulties in raising sufficient numbers of autologous tumor-specific T lymphocytes. On the other hand, the ... |
15163795 | A unified approach to the tedanolides: total synthesis of (+)-13-deoxytedanolide. | A unified approach for the construction of the potent marine antitumor agents (+)-tedanolide (1) and (+)-13-deoxytedanolide (2) is described. Highlights of the synthetic strategy include the development of a versatile bifunctional dithiane-vinyl iodide linchpin, the unorthodox use of the Evans-Tishchenko reaction, and ... |
15163792 | A concise, total synthesis of the TMC-95A/B proteasome inhibitors. | A concise, total synthesis of the proteasome inhibitors TMC-95A/B has been accomplished. The synthesis features the use of an L-serine-derived E-selective modified Julia olefination reaction to ultimately control the stereochemical outcome of the highly oxidized tryptophan fragment. Additionally, the limited use of pro... |
15163794 | Selective deposition of a gadolinium(III) cluster in a hole opening of single-wall carbon nanohorn. | Selective synthesis of particles of angstrom to nanometer size consisting of one to many metal atoms is instrumental in various applications, but it has been hampered by the tendency of the metal atom to form large clusters. We found, as studied by the state-of-the-art electron microscopic technique, a strategy to prod... |
15160314 | Spectroscopic investigation of the nickel-containing porphinoid cofactor F(430). Comparison of the free cofactor in the (+)1, (+)2 and (+)3 oxidation states with the cofactor bound to methyl-coenzyme M reductase in the silent, red and ox forms. | Methyl-coenzyme M reductase (MCR) catalyzes the methane-forming step in methanogenic archaea. It contains the nickel porphinoid F(430), a prosthetic group that has been proposed to be directly involved in the catalytic cycle by the direct binding and subsequent reduction of the substrate methyl-coenzyme M. The active e... |
15216336 | Synthesis and X-ray crystal structures of the first antimony and bismuth calixarene complexes. | The reaction of the monosodium salt of p-tert-butylcalix[4]arene (But)C4) with 2 equivalents of SbCl3 provides ButC4(SbCl)2 and the first bismuth calixarene complex was prepared by treatment of p-tert-butylcalix[8]arene (ButC8) with Bi[N(SiMe3)2]3 in toluene. |
15381984 | Guest sorption and desorption in the metal-organic framework [Co(INA)(2)] (INA=isonicotinate)--evidence of intermediate phases during desorption. | The metal-organic framework [Co(INA)(2)]x0.5EtOH (INA = isonicotinate, NC(5)H(4)-4-CO(2)(-)), was synthesised under solvothermal conditions. Its X-ray crystal structure shows channels containing ethanol guests which are hydrogen-bonded to carboxylate oxygens of the framework. The pyridyl rings of the framework alternat... |
15188042 | Bis(phenylthienyl)ethene-tethered beta-cyclodextrin dimers as photoswitchable hosts. | Two beta-cyclodextrin dimers tethered by photoswitchable bis(phenylthienyl)ethene moieties were synthesized as potentially tunable receptor molecules. The cyclodextrin cavities of these dimers were linked via their secondary sides, with the photochromic bis(phenylthienyl)ethene unit either directly connected to the sec... |
15178874 | Three hexahydropyridopyrimidine-spiro-cyclohexanetriones: supramolecular structures generated by O-H...O, N-H...O, C-H...O and C-H...pi hydrogen bonds, and pi-pi stacking interactions. | 4',4'-Dimethyl-2-methylsulfanyl-3,4,5,6,7,8-hexahydropyrido[2,3-d]pyrimidine-6-spiro-1'-cyclohexane-2',4,6'-trione, C(15)H(19)N(3)O(3)S, (I), has a markedly polarized molecular-electronic structure, and the molecules are linked into a three-dimensional framework by a combination of N-H.O, C-H.O and C-H.pi hydrogen bond... |
15178870 | Molecular conformation and supramolecular aggregation in four 2,3,4,5-tetrahydro-3,4-diphenylbenzothiazepines. | In (2RS,4RS)-1-acetyl-2,3,4,5-tetrahydro-2,4-diphenyl-1,5-benzothiazepine, C(23)H(21)NOS, (I), and (2RS,4RS)-1-chloroacetyl-2,3,4,5-tetrahydro-2,4-diphenyl-1,5-benzothiazepine,C(23)H(20)ClNOS, (II), the seven-membered rings have boat conformations, whereas in (2RS,4RS)-1-benzoyl-2,3,4,5-tetrahydro-2,4-diphenyl-1,5-benz... |
15178847 | (1R,2R)-(-)-Bis[mu4-1-[[1,1-dimethyl-2-(trimethylsilyl)amidino]amino]-2-([1,1-dimethyl-2-[1,1-dimethyl-2-(trimethylsilyl)amidino]amidino]amino)cyclohexane]tetralithium(I). | The title compound, [Li(4)(C(21)H(46)N(8)Si(2))(2)], has been prepared and its structure determined. The whole molecule can be regarded as a molecular cage made up of the central eight-membered ring and six contiguous rings of three types. As the first example of a bridged amidinate-dicyanamide framework, this notewort... |
15178842 | Tris[bis[hydrotris(1-pyrazolyl)borato-kappa3N2,N2',N2"]iron(III)] hexaisothiocyanatoiron(III). | The title compound, [Fe(C(9)H(10)BN(6))(2)](3)[Fe(NCS)(6)] or [Fe(III)(Tp)(2)](3)[Fe(III)(NCS)(6)] [Tp is hydrotris(1-pyrazolyl)borate], crystallizes in space group R-3; the asymmetric unit comprises one-half of an [Fe(Tp)(2)](+) cation, with its Fe atom on a crystallographic inversion centre, and one-sixth of an [Fe(N... |
15159580 | Expression, purification and preliminary X-ray diffraction analysis of a ketoreductase from a type II polyketide synthase. | Polyketide metabolites produced by bacteria and other organisms include antibiotics, anticancer and antifungal compounds. In type II polyketide synthesis, three enzymes are sufficient to form a polyketide product of the requisite chain length, although the fidelity of the first cyclization is variable. Addition of keto... |
15159564 | Structure of concanavalin A at pH 8: bound solvent and crystal contacts. | Concanavalin A has been crystallized in the presence of the ligand (6-S-beta-D-galactopyranosyl-6-thio)-cyclomaltoheptaose. The crystals are isomorphous to those reported for ConA complexed with peptides at low resolution (3.00-2.75 angstroms). The structure was solved at 1.9 angstroms, with free R and R values of 0.20... |
15188038 | Recognition of alpha-amino acid derivatives by N,N'-dibenzylated S,S-(+)-tetrandrine. | Complexation of free and N-acetylated alpha-amino acid anions (Gly, Ala, Phe) and some structurally related guests by a dicationic cyclophane-type N,N'-dibenzylated chiral derivative of a bisisoquinoline macrocyclic alkaloid S,S-(+)-tetrandrine (DBT) has been studied by (1)H-NMR titrations in D(2)O. In contrast to othe... |
15155882 | Woronin body function in Magnaporthe grisea is essential for efficient pathogenesis and for survival during nitrogen starvation stress. | The Woronin body is a peroxisome-derived dense-core vesicle that is specific to several genera of filamentous ascomycetes, where it has been shown to seal septal pores in response to cellular damage. The Hexagonal peroxisome (Hex1) protein was recently identified as a major constituent of the Woronin body and shown to ... |
15155376 | Eukaryotic cells and their cell bodies: Cell Theory revised. | <h4>Background</h4>Cell Theory, also known as cell doctrine, states that all eukaryotic organisms are composed of cells, and that cells are the smallest independent units of life. This Cell Theory has been influential in shaping the biological sciences ever since, in 1838/1839, the botanist Matthias Schleiden and the z... |
15155904 | Molecular sorting by stochastic resonance. | To sort a targeted species from a mixture, we introduce a procedure that relies on the enhancement of its effective diffusion coefficient. We use the formation of a host-guest complex between alpha-cyclodextrin and a dye to evidence the dye dispersion when the medium is submitted to an oscillating field. In particular,... |
15155851 | The high-affinity Sp1 binding site in the HTLV-1 promoter contributes to Tax-independent basal expression. | Transcriptional activation of human T-cell leukemia virus type 1 (HTLV-1) requires many cellular proteins and the virally encoded transcription factor Tax. Tax binds the three viral cAMP-response elements (CREs) with ATF/CREB (activating transcription factor/cAMP-response element-binding protein) and recruits the cellu... |
15155822 | Oligonucleotide hybridization studied by a surface plasmon diffraction sensor (SPDS). | A novel label-free biosensor concept based on surface plasmon-enhanced diffraction by micro- patterned interfaces was applied to the study of hybridization reactions of target DNA oligonucleotides (15mers and 75mers) from solution to probe DNA oligonucleotides attached via streptavidin to the sensor surface. The self-r... |
15381983 | Gold-thallium supramolecular arrays with 4,4'-bipyridine. Solvent induction of luminescent networks. | The reaction of [AuTl(C(6)Cl(5))(2)](n) with bipy at different molar ratios, solvents or crystallisation conditions affords a series of two- and three-dimensional luminescent complexes, [AuTl(C(6)Cl(5))(2)(bipy)(0.5)](n), [AuTl(C(6)Cl(5))(2)(bipy)](n), [[Tl(bipy)][Tl(bipy)(0.5)(THF)][Au(C(6)Cl(5))(2)](2)](n), [[Tl(bipy... |
15188035 | Conformational analysis of mixed oxathia crown ethers and their complexational ability towards Ag(I) and Pd(II)-an experimental solution NMR and theoretical molecular modelling study. | Both the conformation and flexibility of four mixed oxathia crown ethers and their Ag(I) and Pd(II) complexes were studied by (1)H NMR (delta, J, NOE, T(1)), (13)C NMR, dynamic (1)H NMR spectroscopy and molecular modelling. The stoichiometry and stability constants of the complexes were determined from corresponding Jo... |
15252582 | Conformational and stereochemical flexibility in cadmium(II) complexes of aza-thioether macrocycles. | The synthesis and crystal structures of four CdII macrocyclic complexes containing mixed N-, O- and S-donors, [Cd(NO3)2([12]aneN2S2)] (1), [Cd(NO3)2([12]aneNS3)] (2), [Cd(NO3)2([15]aneNO2S2)] (3) and [Cd(NO3)([15]aneN2O2S)]NO3 (4), are presented. The metal ion is coordinated outside of the macrocyclic cavity in the com... |
15150411 | Dynamers: polyacylhydrazone reversible covalent polymers, component exchange, and constitutional diversity. | Component exchange in reversible polymers allows the generation of dynamic constitutional diversity. The polycondensation of dihydrazides with dialdehydes generates polyacylhydrazones, to which the acylhydrazone functionality formed confers both hydrogen-bonding and reversibility features through the amide and imine gr... |
15148405 | Computational design of receptors for an organophosphate surrogate of the nerve agent soman. | We report the computational design of soluble protein receptors for pinacolyl methyl phosphonic acid (PMPA), the predominant hydrolytic product of the nerve agent soman. Using recently developed computational protein design techniques, the ligand-binding pockets of two periplasmic binding proteins, glucose-binding prot... |
15148394 | Membrane growth can generate a transmembrane pH gradient in fatty acid vesicles. | Electrochemical proton gradients are the basis of energy transduction in modern cells, and may have played important roles in even the earliest cell-like structures. We have investigated the conditions under which pH gradients are maintained across the membranes of fatty acid vesicles, a model of early cell membranes. ... |
15148370 | H5N1 influenza: a protean pandemic threat. | Infection with avian influenza A virus of the H5N1 subtype (isolates A/HK/212/03 and A/HK/213/03) was fatal to one of two members of a family in southern China in 2003. This incident was preceded by lethal outbreaks of H5N1 influenza in waterfowl, which are the natural hosts of these viruses and, therefore, normally ha... |
15148361 | Comprehensive search for HNF-1beta-regulated genes in mouse hepatoma cells perturbed by transcription regulatory factor-targeted RNAi. | The identification of genes targeted by a specific transcription regulatory factor (TRF) is essential to our understanding of the regulatory mechanism of gene expression. We constructed a system for the comprehensive identification of genes directly regulated by a TRF. It includes a combination of perturbation of gene ... |
15148360 | Gene delivery by dendrimers operates via a cholesterol dependent pathway. | Understanding the cellular uptake and intracellular trafficking of dendrimer-DNA complexes is an important prerequisite for improving the transfection efficiency of non-viral vector-mediated gene delivery. Dendrimers are synthetic polymers used for gene transfer. Although these cationic molecules show promise as versat... |
15148358 | A three-fluorophore FRET assay for high-throughput screening of small-molecule inhibitors of ribosome assembly. | In one of the first steps of prokaryotic ribosome assembly, the ribosomal protein S15 binds to a three-way junction in the central domain of the 16S rRNA. Binding causes a conformational change that is required for subsequent binding events. Using a novel fluorescence resonance energy transfer assay with three fluoroph... |
15148439 | Methods of crystallochemical analysis of supramolecular complexes by means of Voronoi-Dirichlet polyhedra: a study of cucurbituril host-guest compounds. | Crystallochemical analysis methods based on the Voronoi-Dirichlet partition of crystal space are extended to supramolecular complexes of any complexity. The sizes and shapes of receptor cavities and substrate molecules are shown to be successfully estimated as volumes and the second moments of inertia of the correspond... |
15146175 | Hierarchically mesostructured doped CeO2 with potential for solar-cell use. | Many properties provided by supramolecular chemistry, nanotechnology and catalysis only appear in solids exhibiting large surface areas and regular porosity at the nanometre scale. In nanometre-sized particles, the ratio of the number of atoms in the surface to the number in the bulk is much larger than for micrometre-... |
15169567 | Early steps of retrovirus replicative cycle. | During the last two decades, the profusion of HIV research due to the urge to identify new therapeutic targets has led to a wealth of information on the retroviral replication cycle. However, while the late stages of the retrovirus life cycle, consisting of virus replication and egress, have been partly unraveled, the ... |
15381979 | A novel self-assembling synthesis and crystal structure of 40-membered macrocyclic complex containing eight-tin. | The self-assembly reaction of 2-mercapto-4-methyl-5-thiazoleacetic acid, sodium methoxide and dimethyltin dichloride in moist dichloromethane affords a novel eight-tin macrocyclic complex, which is a 40-membered macrocycle containing two distannoxane ladders. |
15312215 | The influence of N-acetyl-L-cystein infusion on cytokine levels and gastric intramucosal pH during severe sepsis. | <h4>Introduction</h4>The purpose of the present study was to evaluate the effects of continuously infused N-acetyl-L-cystein (NAC) on serum cytokine levels and gastric intramucosal pH in humans suffering from severe sepsis.<h4>Methods</h4>Fifty-three patients were included in the study. In the NAC group (n = 27), after... |
15146065 | Cholera toxin toxicity does not require functional Arf6- and dynamin-dependent endocytic pathways. | Cholera toxin (CT) and related AB(5) toxins bind to glycolipids at the plasma membrane and are then transported in a retrograde manner, first to the Golgi and then to the endoplasmic reticulum (ER). In the ER, the catalytic subunit of CT is translocated into the cytosol, resulting in toxicity. Using fluorescence micros... |
15146059 | Characterization of a nonclathrin endocytic pathway: membrane cargo and lipid requirements. | Clathrin-independent endocytosis internalizes plasma membrane proteins that lack cytoplasmic sequences recognized by clathrin adaptor proteins. There is evidence for different clathrin-independent pathways but whether they share common features has not been systematically tested. Here, we examined whether CD59, an endo... |
15146056 | Mitosis-specific anchoring of gamma tubulin complexes by pericentrin controls spindle organization and mitotic entry. | Microtubule nucleation is the best known function of centrosomes. Centrosomal microtubule nucleation is mediated primarily by gamma tubulin ring complexes (gamma TuRCs). However, little is known about the molecules that anchor these complexes to centrosomes. In this study, we show that the centrosomal coiled-coil prote... |
15146057 | The entire Nup107-160 complex, including three new members, is targeted as one entity to kinetochores in mitosis. | In eukaryotes, bidirectional transport of macromolecules between the cytoplasm and the nucleus occurs through elaborate supramolecular structures embedded in the nuclear envelope, the nuclear pore complexes (NPCs). NPCs are composed of multiple copies of approximately 30 different proteins termed nucleoporins, of which... |
15146055 | Transmembrane peptides as inhibitors of ErbB receptor signaling. | Receptor tyrosine kinases have a single transmembrane (TM) segment that is usually assumed to play a passive role in ligand-induced dimerization and activation of the receptor. However, mutations within some of these receptors, and recent studies with the epidermal growth factor (EGF) and ErbB2 receptors have indicated... |
15179481 | Effective cation-assisted chirality induction using a dibenzo-diaza-30-crown-10 with bis(zinc(II) porphyrin) units. | The first rationalized crown ether-bis(porphyrin) conjugate with a large ring-based conformation flexibility 1 has been synthesized; the achiral-to-chiral transformation upon complexation with chiral diamines is assisted by K(+) accommodated in the crowned moiety, and it is possible to determine the chirality of carbox... |
15141166 | Functional integration of the histone acetyltransferase MOF into the dosage compensation complex. | Dosage compensation in flies involves doubling the transcription of genes on the single male X chromosome to match the combined expression level of the two female X chromosomes. Crucial for this activation is the acetylation of histone H4 by the histone acetyltransferase (HAT) MOF. In male cells, MOF resides in a compl... |
15143068 | Cell growth regulation through GM3-enriched microdomain (glycosynapse) in human lung embryonal fibroblast WI38 and its oncogenic transformant VA13. | Cell growth control mechanisms were studied based on organization of components in glycosphingolipid-enriched microdomain (GEM) in WI38 cells versus their oncogenic transformant VA13 cells. Levels of fibroblast growth factor receptor (FGFR) and cSrc were 4 times and 2-3 times higher, respectively, in VA13 than in WI38 ... |
15143214 | NFAM1, an immunoreceptor tyrosine-based activation motif-bearing molecule that regulates B cell development and signaling. | A functional cDNA cloning system was developed by using a retrovirus library encoding CD8-chimeric proteins and a nuclear factor of activated T cells (NFAT)-GFP reporter cell line to identify molecules inducing NFAT activation. By using this strategy, NFAT activating molecule 1 (NFAM1) was cloned as an immunoreceptor t... |
15263926 | Perylene bisimide dyes as versatile building blocks for functional supramolecular architectures. | Perylene bisimide dyes and their organization into supramolecular architectures through hydrogen-bonding, metal ion coordination and pi-pi-stacking is discussed; further self-assembly leading to nano- and meso-scopic structures and liquid-crystalline compounds is also addressed. |
15141081 | Mechanical tweezer action by self-tightening knots in surfactant nanotubes. | Entanglements and trefoil knots on surfactant nanotubes in the liquid phase were produced by a combination of network self-organization and micromanipulation. The resulting knots are self-tightening, and the tightening is driven by minimization of surface free energy of the surfactant membrane material. The formation o... |
15179473 | Phase selectively soluble dendrimer-bound osmium complex: a highly effective and easily recyclable catalyst for olefin dihydroxylation. | A new switched biphasic catalysis system for highly effective olefin dihydroxylation has been described, in which the dendritic osmium catalyst preferred to dissolve in the non-polar organic layer and could be easily separated from the polar diol products through phase separation induced by addition of water at the end... |
15178861 | The supramolecular structure of 6-hydroxy-1,3-benzoxathiol-2-one (tioxolone). | The planar molecules of 6-hydroxy-1,3-benzoxathiol-2-one, C(7)H(4)O(3)S, are linked by extensive O-H.O and C-H.O hydrogen bonding and are further stablilized by face-to-face pi-pi interactions. |
15178856 | 4,4,6,6-Tetrachloro-2,2-(propylenedioxydi-o-phenylenediimino)-2lambda5,4lambda5,6lambda5-cyclotriphosphazene. | The title compound, C(15)H(16)Cl(4)N(5)O(2)P(3), is a cyclophosphazenic lariat (PNP-pivot) ether with a spiro-cyclic 12-membered macrocyclic ligand containing two ether O and two N atoms; the phosphazene ring is nearly planar. In the macrocyclic ring, there is a four-center (trifurcate) N-H.O/N-H.N hydrogen bond. The r... |
15138257 | Complex structures of Thermoactinomyces vulgaris R-47 alpha-amylase 2 with acarbose and cyclodextrins demonstrate the multiple substrate recognition mechanism. | Thermoactinomyces vulgaris R-47 alpha-amylase 2 (TVAII) has the unique ability to hydrolyze cyclodextrins (CDs), with various sized cavities, as well as starch. To understand the relationship between structure and substrate specificity, x-ray structures of a TVAII-acarbose complex and inactive mutant TVAII (D325N/D421N... |
15138258 | Cargo proteins facilitate the formation of transport vesicles in the cytoplasm to vacuole targeting pathway. | Selective incorporation of cargo proteins into the forming vesicle is an important aspect of protein targeting via vesicular trafficking. Based on the current paradigm of cargo selection in vesicular transport, proteins to be sorted to other organelles are condensed at the vesicle budding site in the donor organelle, a... |
15138299 | Programmable motion and patterning of molecules on solid surfaces. | Adsorbed on a solid surface, a molecule can migrate and carry an electric dipole moment. A nonuniform electric field can direct the motion of the molecule. A collection of the same molecules may aggregate into a monolayer island on the solid surface. Place such molecules on a dielectric substrate surface, beneath which... |
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