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14691140 | Isoform-specific insulin receptor signaling involves different plasma membrane domains. | In pancreatic beta-cells, insulin selectively up-regulates the transcription of its own gene and that of the glucokinase gene by signaling through the two isoforms of the insulin receptor, i.e., A-type (Ex11-) and B-type (Ex11+), using different signaling pathways. However, the molecular mechanism(s) that allows the di... |
14691137 | Recognition of dileucine-based sorting signals from HIV-1 Nef and LIMP-II by the AP-1 gamma-sigma1 and AP-3 delta-sigma3 hemicomplexes. | The sorting of transmembrane proteins to endosomes and lysosomes is mediated by signals present in the cytosolic tails of the proteins. A subset of these signals conform to the [DE]XXXL[LI] consensus motif and mediate sorting via interactions with heterotetrameric adaptor protein (AP) complexes. However, the identity o... |
14686851 | Trinuclear to dinuclear: a radii dependence lanthanide(III) self-assembly coordination behavior of an amide-type tripodal ligand. | Lanthanide nitrate complexes with the heptadentate ligand L (6-[2-(2-(diethylamino)-2-oxoethoxy)ethyl]-N,N,12-triethyl-11-oxo-3,9-dioxa-6,12-diazatetradecanamide), [Ln(2)L(NO(3))(6)] (Ln = La, Nd, Sm, Eu, Ho), have been prepared and characterized. The X-ray crystallographic studies show that, in [La(2)L(NO(3))(6)(H(2)O... |
14686848 | Diastereoselectivity and molecular recognition in the self-assembly of double-stranded dinuclear metal complexes of the type [M2[(R,S)-tetraphos]2](PF6)2 (M = Ag and Au). | The ligand (R,S)-Ph(2)PCH(2)CH(2)P(Ph)CH(2)CH(2)P(Ph)CH(2)CH(2)PPh(2), (R,S)-tetraphos, combines with silver(I) and gold(I) ions in the presence of hexafluorophosphate to diastereoselectively self-assemble the head-to-head (H,H) diastereomers of the double-stranded, dinuclear metal complexes [M(2)[(R,S)-tetraphos](2)](... |
14686839 | A [2]catenane constructed around a rhodium(III) center used as a template. | Rhodium(III) has been used as a templating metal center for building a [2]catenane. In the first stage, a Rh(phen)(2) motif has been incorporated into a large ring. Subsequently, a 2,2'-bipyridine derivative has been threaded through the ring, this process being driven by coordination of the chelate to the Rh(III) cent... |
14682767 | Supramolecular structures formed by calix[8]arene derivatives. | Octamethoxy calix[8]arenes substituted in the para position by amide, urea, and imide functions were synthesized from the octamethyl ether of tert-butylcalix[8]arene by ipso nitration, reduction, and acylation. Scanning force microscopy of spin coated samples on graphite suggests that these derivatives self-organize in... |
14682761 | Synthesis of the chlorofusin cyclic peptide: assignment of the asparagine stereochemistry. | An efficient synthesis of two diastereomers of the chlorofusin cyclic peptide bearing either the l-Asn3/d-Asn-4 or d-Asn3/l-Asn4 stereochemistry is detailed. Four key subunits were prepared, sequentially coupled, and cyclized to provide the two diastereomeric macrocycles. The absolute stereochemistry at the asparagine ... |
14682751 | Postcolumn HPLC detection of mono- and oligosaccharides with a chemosensor. | Novel chromophoric compound 1 promotes the HPLC postcolumn detection of mono- and oligosaccharides. The detection of chromatographic peaks in the visible region for glucose, fructose, maltodextrins, sialic acid, and a ganglioside can be accomplished with a standard UV-vis detector. The use of selective, reversible bind... |
14682742 | A novel ditopic receptor and reversal of anion binding selectivity in the presence and absence of bound cation. | A calix[4]arene-derived ditopic receptor 1 has been synthesized. In the absence of Na+, the receptor binds acetate in preference to diphenyl phosphate (as the tetrabutylammonium salts), but in the presence of Na+, the selectivity is reversed and the receptor, instead, binds diphenyl phosphate, and not acetate, which pr... |
14682733 | Proofs of macrocyclization of gable porphyrins as mimics of photosynthetic light-harvesting complexes. | Porphyrin macrocycles composed of five and six units of m-gable imidazolylporphyrinatozinc (1-Zn) were synthesized by self-assembled cyclization followed by ring-closing metathesis linkings. Each porphyrin macrocycle was isolated by GPC chromatography, and their molecular weights were determined by MALDI-TOF mass spect... |
14682730 | Rotaxane-stabilized thiophosphonium salt from disulfide and phosphine. | The reaction of a rotaxanated disulfide with hexamethylphosphorustriamide afforded a stable thiophosphonium salt in rotaxanated form. The structure of the thioposphonium salt was confirmed by spectroscopic and X-ray crystal structure analyses. The successful isolation of this salt was attributed to the special stabiliz... |
14682714 | Triton X-100 enhances ion-pair-driven molecular recognition in aqueous media. Further work on a chemosensor for inositol trisphosphate. | Molecular recognition in water based on ion-pairing is hampered by competition from the solvent. We have reported that synthetic receptor 1 recognizes inositol trisphosphate (IP3) with a binding constant of 10(8) M(-1) in methanol. In this paper, instead of working in methanol, we report that the surfactant Triton-X 10... |
14682702 | Synthesis and supramolecular properties of conformationally restricted and flexible phospholipids. | Short synthetic routes are described to produce structurally related phospholipids that are either conformationally restricted or flexible. The conformationally restricted structures have a cyclopropyl ring in the interfacial region of the phospholipid. The key synthetic step is a cyclopropanation reaction between 2(5H... |
14685687 | Pathogenic enterococci: new developments in the 21st century. | Enterococci, traditionally viewed as Gram-positive commensal bacteria inhabiting the alimentary canals of humans and animals, are now acknowledged to be organisms capable of causing life-threatening infections in humans, especially in the nosocomial environment. The existence of enterococci in such a dual role is facil... |
14685685 | Forming facultative heterochromatin: silencing of an X chromosome in mammalian females. | Compensating for the dosage difference in X-linked genes between male and female mammals involves the formation of an extremely stable heterochromatin structure on one of the two X chromosomes in females. The inactive X acquires numerous features of silent chromatin, including the expression of a noncoding RNA, a switc... |
14680229 | Synthetic studies on ecteinascidin 743: rapid access to the fully functionalized tetrahydroisoquinoline with a bridged 10-membered sulfur containing macrocycle. | Synthesis of tetrahydroisoquinoline with a 1,4-bridged 10-membered sulfur containing macrolactone (5) is described. Phenolic aldolisation, Pictet-Spengler cyclisation of an acid sensitive amino diol under newly developed conditions (LiBr, toluene-TFE, 80 degrees C) and acid promoted intramolecular C-S bond formation le... |
14680228 | Efficient preparation of 1,4,8-trimethylcyclam and its conversion into a thioalkyl-pendant pentadentate chelate. | A facile synthesis of 1,4,8-trimethylcyclam and a thioalkyl-pendant derivative are reported, and the X-ray crystal structure of a nickel(II) complex illustrates structural consequences of appending the thiolate donor onto the macrocycle. |
14680220 | A supramolecular approach to lithium ion solvation at nanostructured dye sensitised inorganic/organic heterojunctions. | A novel arylamine based hole transporting material (HTM) with tetraethylene glycol (TEG) side groups is reported. Lithium ions solubilised by the TEG groups are employed to modulate interfacial electron transfer reactions at a dye sensitised TiO2/HTM interface. |
14680208 | A metallosupramolecular tetrahedron with a huge internal cavity. | A huge molecular tetrahedral complex forms quantitatively by self-assembly from four ligands L-H6 and four titanium(IV) ions; in the solid state it encapsulates four [K(DIMF)3]+ units in its interior. |
14677989 | Application of isomorphous replacement in the structure determination of a cubic liquid crystal phase and location of counterions. | A second generation monodendron with dodecyl end-groups based on the AB(3) monomer 3,4,5-trihydroxy benzoate has previously been shown to form a thermotropic cubic phase with Pmthremacr;n symmetry (Balagurusamy et al., J. Am. Chem. Soc. 1997, 119, 1539). A structure consisting of spherical "micelles" was proposed origi... |
14677984 | Structural characterization of crystalline ternary inclusion compounds at the air-water interface. | Crystalline ternary inclusion monolayers consisting of a two-dimensional hydrogen-bonded host network of guanidinium (G) ions and organosulfonate (S) amphiphiles, and biphenylalkane guests, can be generated at the air-water interface through synergistic structural enforcement by hydrogen bonding and host-guest packing.... |
14677954 | Chiral bisphosphine BINAP-stabilized gold and palladium nanoparticles with small size and their palladium nanoparticle-catalyzed asymmetric reaction. | The reduction of tetrachloroaurate or potassium tetrachloropalladate with sodium borohydride in the presence of optically active 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl [BINAP] gave the chiral (S)- or (R)-BINAP-stabilized gold or palladium nanoparticles which showed the small core (1.7 nm for BINAP-Au and 2.0 nm fo... |
14677944 | A novel supramolecular multicolor thermometer by self-assembly of a pi-extended zinc porphyrin complex. | A zinc complex of (3-pyridyl)porphyrin with an alkynyl sidearm (1) preferentially formed a cyclic tetramer in toluene, which showed supramolecular thermochromism at ambient temperatures of 0-100 degrees C. Because of an appropriate extension of pi-electronic conjugation of the porphyrin chromophore, the thermal-induced... |
14677927 | Geometric disassembly of dendrimers: dendritic amplification. | Geometric disassembly of dendritic structures was realized by a cascade cleavage reaction triggered by an initially stimulated group at the dendrimer core. Release of an exponential number of dendrimer fragments was a result of the branching nature of the cleavage pathway. Evidence for the completion of the disassembly... |
14679572 | Partial filling technique in capillary electrophoresis for the separation of phenolic isomers with sulfonatocalix[4]arene as a selector. | p-Sulfonatocalix[4]arene was used as a selector in capillary electrophoresis to separate phenolic positional isomers. To avoid the detection interference caused by the high UV absorption of calixarene, the partial filling technique was applied. The operation variables, including buffer, separation voltage, the concentr... |
14679528 | Synthesis of conjugated polyrotaxanes. | A series of conjugated polyrotaxane insulated molecular wires are synthesised by aqueous Suzuki polymerisation, using hydrophobic binding to promote threading of the cyclodextrin units. These polyrotaxanes have conjugated polymer cores based on poly(para-phenylene), polyfluorene, and poly(diphenylene-vinylene), threade... |
14679519 | Novel podands and macrocycles with diacetal (tetraoxadecalin) cores: synthesis, structure, stereochemistry and cation inclusion. | A series of functionalized 2,6-dialkyl-cis-1,3,5,7-tetraoxadecalin podands (3-10, alkyl = hydroxy-, mesyloxy-, halo-, azido- and aminomethyl and -ethyl) were prepared, characterized, and used as precursors for a new and interesting class of macrocycles and cryptands (12-21), with the aim to use these as host-guest incl... |
14679515 | Photocurrent generation in multilayer self-assembly films fabricated from water-soluble poly(phenylene vinylene). | A novel, water-soluble, cationic PPV derivative poly[(2,5-bis(3-bromotrimethylammoniopropoxy)-phenylene-1,4-divinylene)-alt-1,4-(2,5-bis(2-(2-hydroxyethoxy)ethoxy))phenylene vinylene] (BH-PPV) has been synthesized by a Heck coupling reaction. Multilayered assemblies of the BH-PPV and the sodium salt of hexa(sulfobutyl)... |
14679511 | Assembled dendritic titanium catalysts for enantioselective hetero-Diels-Alder reaction of aldehydes with Danishefsky's diene. | A new type of dendritic 2-amino-2'-hydroxy-1,1'-binaphthyl (NOBIN)-derived Schiff-base ligands have been synthesized and applied to the titanium-catalyzed hetero-Diels-Alder reaction of Danishefsky's diene with aldehydes. These reactions afforded the corresponding 2-substituted 2,3-dihydro-4H-pyran-4-ones in quantitati... |
14679510 | Installation of a ratchet tooth and pawl to restrict rotation in a cyclodextrin rotaxane. | Eight new [2]rotaxanes have been prepared, incorporating an alpha-cyclodextrin as the rotor, a stilbene as the axle, and trinitrophenyl substituents as capping groups. Strategies have been devised to elaborate these by linking the rotor to the axle, to produce two new [1]rotaxanes. Rotational motion in a selection of t... |
14679509 | Separated and aligned molecular fibres in solid state self-assemblies of cyclodextrin [2]rotaxanes. | The conformations of two [2]rotaxanes, each comprising alpha-cyclodextrin as the rotor, a stilbene as the axle and 2,4,6-trinitrophenyl substituents as the capping groups, have been examined in solution and in the solid state, using (1)H NMR spectroscopy and X-ray crystallography, respectively. In solution, introducing... |
14676297 | CD226 (DNAM-1) is involved in lymphocyte function-associated antigen 1 costimulatory signal for naive T cell differentiation and proliferation. | Upon antigen recognition by the T cell receptor, lymphocyte function-associated antigen 1 (LFA-1) physically associates with the leukocyte adhesion molecule CD226 (DNAM-1) and the protein tyrosine kinase Fyn. We show that lentiviral vector-mediated mutant (Y-F322) CD226 transferred into naive CD4+ helper T cells (Ths) ... |
14675543 | Molecular shredders: how proteasomes fulfill their role. | The 20S proteasome is a large, cylinder-shaped protease that is found in all domains of life and plays a crucial role in cellular protein turnover. It has multiple catalytic centers located within the hollow cavity of a molecular cage. This architecture prevents unwanted degradation of endogenous proteins and promotes ... |
14676813 | Selectivity of the photosensitiser Tookad for photodynamic therapy evaluated in the Syrian golden hamster cheek pouch tumour model. | The response to photodynamic therapy (PDT) with the photosensitiser (PS) Tookad was measured in the Syrian hamster cheek pouch model on normal mucosae and chemically induced squamous cell carcinoma. This PS is a palladium-bacteriopheophorbide presenting absorption peaks at 538 and 762 nm. The light dose, drug dose and ... |
14674784 | Ligand-bridged oligomeric and supramolecular arrays of the hexanuclear rhenium selenide clusters--exploratory synthesis, structural characterization, and property investigation. | Transition metal clusters, by virtue of their well-defined structures and unique properties, present themselves as an attractive class of structural and functional building blocks for molecular and supramolecular construction. Summarized in this Account are highlights of our efforts utilizing face-capped octahedral [Re... |
14674783 | Molecular tweezers and clips as synthetic receptors. Molecular recognition and dynamics in receptor-substrate complexes. | The molecular tweezers (1, 2) and clips (3-7) containing naphthalene and benzene spacer units can be synthesized via repetitive Diels-Alder reactions by the use of a molecular "Lego" set consisting of bisdienophiles (8, 9, 14) and dienes (10, 13). The new receptors selectively bind electron-deficient neutral and cation... |
14667296 | Organic materials for second-harmonic generation: advances in relating structure to function. | The relationships between molecular structure and the nonlinear optical phenomenon second-harmonic generation (SHG) are discussed. New-found relationships built up from basic structural axioms that were deduced in the 1970s and 1980s are the particular focus of this article, using structural results from X-ray and neut... |
14657385 | NMR-detected hydrogen exchange and molecular dynamics simulations provide structural insight into fibril formation of prion protein fragment 106-126. | PrP106-126, a peptide corresponding to residues 107-127 of the human prion protein, induces neuronal cell death by apoptosis and causes proliferation and hypertrophy of glia, reproducing the main neuropathological features of prion-related transmissible spongiform encephalopathies, such as bovine spongiform encephalopa... |
14657383 | Induced-fit recognition of DNA by organometallic complexes with dynamic stereogenic centers. | Organometallic chemistry offers novel concepts in structural diversity and molecular recognition that can be used in drug design. Here, we consider DNA recognition by eta 6-arene Ru(II) anticancer complexes by an induced-fit mechanism. The stereochemistry of the dinuclear complex [((eta 6-biphenyl)RuCl(en))2-(CH2)6]2 +... |
14657372 | Chlorophyll breakdown: pheophorbide a oxygenase is a Rieske-type iron-sulfur protein, encoded by the accelerated cell death 1 gene. | Chlorophyll (chl) breakdown during senescence is an integral part of plant development and leads to the accumulation of colorless catabolites. The loss of green pigment is due to an oxygenolytic opening of the porphyrin macrocycle of pheophorbide (pheide) a followed by a reduction to yield a fluorescent chl catabolite.... |
14657358 | A class of sterol 14-demethylase inhibitors as anti-Trypanosoma cruzi agents. | Chronic infection with the protozoan parasite Trypanosoma cruzi is a major cause of morbidity and mortality in Latin America. Drug treatments for the associated illness, Chagas disease, are toxic and frequently unsuccessful. In a screening effort against the drug target protein farnesyltransferase, we identified a seri... |
14665680 | A continuum of anionic charge: structures and functions of D-alanyl-teichoic acids in gram-positive bacteria. | Teichoic acids (TAs) are major wall and membrane components of most gram-positive bacteria. With few exceptions, they are polymers of glycerol-phosphate or ribitol-phosphate to which are attached glycosyl and D-alanyl ester residues. Wall TA is attached to peptidoglycan via a linkage unit, whereas lipoteichoic acid is ... |
14665678 | Molecular basis of bacterial outer membrane permeability revisited. | Gram-negative bacteria characteristically are surrounded by an additional membrane layer, the outer membrane. Although outer membrane components often play important roles in the interaction of symbiotic or pathogenic bacteria with their host organisms, the major role of this membrane must usually be to serve as a perm... |
14664595 | Assembly of an electronically switchable rotaxane on the surface of a titanium dioxide nanoparticle. | This paper describes the self-assembly of a heterosupramolecular system consisting of a tripodal [2]rotaxane adsorbed at the surface of a titanium dioxide nanoparticle. The tripodal [2]rotaxane consists of a dumbbell-shaped molecule, incorporating two electron-poor viologens, threading an electron-rich crown ether. The... |
14664594 | Dendritic molecular capsules for hydrophobic compounds. | Reichardt's dye, a highly solvatochromic dye, was encapsulated within poly (glycerol succinic acid) ([Gn]-PGLSA-OH) dendrimers to investigate the interior environment of these dendritic macromolecules. The absorption maximum for the encapsulated Reichardt's dye in water was indicative of a relatively high dielectric co... |
14664570 | Synthesis, structure, and reaction of 1-alkynyl(aryl)-lambda3-bromanes. | Reported here for the first time are the synthesis, structure, and reaction of hypervalent 1-alkynyl(aryl)-lambda3-bromanes. BF3-catalyzed ligand exchange on bromine(III) of p-trifluoromethylphenyl(difluoro)-lambda3-bromane with 1-alkynyl(trimethyl)stannanes in dichloromethane at -78 degrees C afforded 1-alkynyl(aryl)-... |
14664569 | Orthogonal control of dissociation dynamics relative to thermodynamics in a main-chain reversible polymer. | A pair of homologous and soluble reversible polymers display nearly identical solution structures but dramatically different dissociation dynamics (1.0 vs ca. 100 s-1) along their main chains. The polymers are formed by organopalladium-pyridine coordination, and steric effects at the metal center control the dynamics. ... |
14665461 | EAP1, a Candida albicans gene involved in binding human epithelial cells. | Candida albicans adhesion to host tissues contributes to its virulence and adhesion to medical devices permits biofilm formation, but we know relatively little about the molecular mechanisms governing C. albicans adhesion to materials or mammalian cells. Saccharomyces cerevisiae provides an attractive model system for ... |
14665457 | Molecular identification of a calcium-inhibited catalytic subunit of casein kinase type 2 from Paramecium tetraurelia. | We have previously described the occurrence in Paramecium of a casein kinase (CK) activity (EC 2.7.1.37) with some unusual properties, including inhibition by Ca(2+) (R. Kissmehl, T. Treptau, K. Hauser, and H. Plattner, FEBS Lett. 402:227-235, 1995). We now have cloned four genes, PtCK2alpha1 to PtCK2alpha4, all of whi... |
14662915 | Growth of Helicobacter pylori in medium supplemented with cyanobacterial extract. | Solid and liquid media supplemented only with a cyanobacterial extract (CE) and free of fetal calf serum (FCS), blood, and its derivatives support the growth of Helicobacter pylori. A total of 11 strains of H. pylori isolated from gastric biopsy samples were successfully subcultured in Mueller-Hinton agar supplemented ... |
14661748 | Development and validation of a liquid chromatography-ultraviolet absorbance detection assay using derivatisation for the novel marine anticancer agent ES-285 x HCl [(2S,3R)-2-amino-3-octadecanol hydrochloride] and its pharmaceutical dosage form. | ES-285 x HCl [(2S,3R)-2-amino-3-octadecanol hydrochloride] is a novel investigational anticancer agent, which has shown in vitro and in vivo cytotoxic activity against various tumor cell lines with selectivity for certain solid tumors. The pharmaceutical development of ES-285 x HCl warranted the availability of an assa... |
14659051 | [Clinical significance of detection of serum hyaluronic acid concentration in severe burn patients]. | <h4>Objective</h4>To study the relationship between the changes in serum hyaluronic acid (HA) concentrations and injury of hepatocytes in severe burn patients.<h4>Methods</h4>Radioimmunoassay and enzyme-linked immunosorbent assay (ELISA) were used to detect HA and tumor necrosis factor-alpha(TNF-alpha) concentrations i... |
14658911 | Systematic evaluation of molecular recognition phenomena. 3. Selective diphosphate binding to isomeric hexaazamacrocyclic ligands containing xylylic spacers. | The crystal structure of 3,7,11,18,22,26-hexaazatricyclo[26.2.2.2(13,16)]tetratriaconta-1(31),13(34),14,16(33),28(32),29-hexaene hexahydrobromide salt [(H6P3)Br6] has been determined by means of X-ray diffraction analysis. It crystallizes with an additional molecule of ethanol and half a molecule of water per molecule ... |
14658877 | The Pacman effect: a supramolecular strategy for controlling the excited-state dynamics of pillared cofacial bisporphyrins. | The molecular recognition properties of dizinc(II) bisporphyrin anchored by dibenzofuran (DPD), Zn2(DPD) (1), were evaluated as a strategy for utilizing the Pacman effect to control the excited-state properties of cofacial bisporphyrin motifs. Crystallographic studies establish that DPD furnishes a cofacial system with... |
14658875 | Coexistence of water dimer and hexamer clusters in 3D metal-organic framework structures of Ce(III) and Pr(III) with pyridine-2,6-dicarboxylic acid. | Ce(NO3)3.6H2O or Pr(NO3)3.6H2O and pyridine-2,6-dicarboxylic acid form a linear coordination polymeric structure under hydrothermal conditions. Hexameric water clusters join these linear chains through bonding to the metal ions. Other coordinated water and the carboxylate oxygen form an intricate array of hydrogen bond... |
14658869 | Tetraphosphinitoresorcinarene complexes: cationic silver(I) and copper(I) halide complexes as mercurate(II) anion receptors. | The reactions of mercury(II) halides with the tetraphosphinitoresorcinarene complexes [P4M5X5], where M=Cu or Ag, X=Cl, Br, or I, and P4=(PhCH2CH2CHC6H2)4(O2CR)4(OPPh2)4 with R=C6H11, 4-C6H4Me, C4H3S, OCH2CCH, or OCH2Ph, have been studied. The reactions of the complexes with HgX2 when M=Ag and X=Cl or Br occur with eli... |
14658868 | Octalkoxy-substituted phosphorus(V) triazatetrabenzcorroles via ring contraction of phthalocyanine precursors. | As part of efforts toward developing the synthesis of novel corrole analogues, the new triazatetrabenzcorrole (TBC) phosphorus(V) compounds (BuO)8(TBC)P(OCH3)2 (3), [(BuO)8(TBC)P(OH)]+OH- (4) ((BuO)8TBC=3,6,10,13,17,20,24,27-octabutoxytriazatetrabenzcorrolate), and [(BuO)8Cl8(TBC)P(OH)]+OH- (7) ((BuO)8Cl8TBC=3,6,10,13,... |
14658864 | Synthesis of open and closed metallacages using novel tripodal ligands: unusually stable silver(I) inclusion compound. | The tripodal ligand 1,3,5-(CH3)3C6[CH2OCH2C(pz)3]3 (L1, pz=pyrazolyl ring) reacts with AgBF4 to yield ([L12Ag3(CH3CN)](BF4)3).(CH3CN)4, an inclusion complex in which the encapsulated acetonitrile cannot escape the triangular cage unit in either the solid or solution phase. The analogous hexatopic ligand C6[CH2OCH2C(pz)... |
14661235 | Recent advances in the determination of enantiomeric drugs and their metabolites in biological fluids by capillary electrophoresis-mediated microanalysis. | This review summarizes the recent developments in the application of electromigration techniques for the enantioselective analysis of drugs and metabolites in biological fluids. During the period covered by this review, it has been observed an increase in the use of negatively charged chiral selectors, particularly sul... |
14661234 | Recent advances in enantioseparations of peptides by capillary electrophoresis. | The present review summarizes peptide enantioseparations by capillary electrophoresis with the focus on recent developments. These include the application of new chiral selectors and systematic studies involving series of di- and tripeptides with either common features or with a variety of structures. One section empha... |
14661275 | DNA mismatch-specific base flipping by a bisacridine macrocycle. | Most, if not all, enzymes that chemically modify nucleobases in DNA flip their target base from the inside of the double helix into an extrahelical position. This energetically unfavorable conformation is partly stabilized by specific binding of the apparent abasic site being formed. Thus, DNA base-flipping enzymes, li... |
14661272 | Chemoenzymatic synthesis of branched oligo- and polysaccharides as potential substrates for starch active enzymes. | Oligo- and polysaccharides embodying the alpha-maltotriosyl-6(II)-maltotetraosyl structure were readily synthesized by transglycosylation of maltosyl fluoride onto panose and pullulan catalysed by the bacterial transglycosylase cyclodextrin glycosyltransferase (CGTase). The two products obtained proved useful for incre... |
14660360 | Identification and characterization of benzimidazole resistance in Monilinia fructicola from stone fruit orchards in California. | Low and high levels of resistance to the benzimidazole fungicides benomyl and thiophanate-methyl were observed in field isolates of Monilinia fructicola, which is the causative agent of brown rot of stone fruit. Isolates that had low levels of resistance (hereafter referred to as LR isolates) and high levels of resista... |
14656441 | The yeast YPD1/SLN1 complex: insights into molecular recognition in two-component signaling systems. | In Saccharomyces cerevisiae, a branched multistep phosphorelay signaling pathway regulates cellular adaptation to hyperosmotic stress. YPD1 functions as a histidine-phosphorylated protein intermediate required for phosphoryl group transfer from a membrane-bound sensor histidine kinase (SLN1) to two distinct response re... |
14656597 | Improving microdialysis extraction efficiency of lipophilic eicosanoids. | Microdialysis recovery of the lipophilic analytes prostaglandin B2, leukotriene B4 and C4 was studied in vitro. Relative recovery (RR) through different commercially-available microdialysis probes for prostaglandin B2 and leukotrienes was examined using different flow rates. The enhancing effect at different concentrat... |
14656114 | Molecular recognition of alkylammonium contact ion-pairs using a ditopic receptor. | A ditopic, macrobicyclic receptor with adjacent anion and cation binding sites is able to distinguish between various monoalkylammonium salts by binding them as contact ion-pairs. The affinity for linear n-propylammonium chloride is at least 2 orders of magnitude greater than that for n-propylammonium acetate, n-propyl... |
14656110 | Synthesis and optical properties of polyphenylene dendrimers based on perylenes. | A series of polyphenylene-dendronized perylenes have been synthesized, and their physical and mesoscopic properties have been investigated. The attached polyphenylene dendrons have significant effects on the physical properties of the perylenes. They increase the solubility of perylenes in common organic solvents, supp... |
14656109 | Bidentate ligands capable of variable bond angles in the self-assembly of discrete supramolecules. | Flexible donor ligands like 1,2-bis(3-pyridyl)ethyne or 1,4-bis(3-pyridyl)-1,3-butadiyne self-assemble into discrete supramolecules instead of infinite networks upon combination with organoplatinum 90, 120, and 180 degree acceptor units. These systems are unique examples of versatile pyridine donors adjusting their bon... |
14656108 | Amphiphilic diblock dendrimers with a fullerene core. | Amphiphilic dendrimers with a C(60) core have been obtained by cyclization of dendritic 1,3-phenylenebis(methylene)-tethered bis-malonate derivatives at the carbon sphere. The relative position of the two cyclopropane rings in the resulting bis-methanofullerene derivatives has been determined based on the molecular sym... |
14656096 | Synthesis of poly(propyl ether imine) dendrimers and evaluation of their cytotoxic properties. | In this paper, we report the synthesis of several poly(propyl ether imine) dendrons and dendrimers. These dendrons and dendrimers were constructed by involving an ether as the linker component and an imine as the branching component. The divergent syntheses of dendrons and dendrimers were established with the aid of tw... |
14656081 | Synthesis of polyfunctionalized biphenyls as intermediates for a new class of liquid crystals. | A series of hexa- and octasubstituted biphenyls containing halogen, amino, nitro, and propylthio substituents were prepared by metal-mediated convergent synthesis from halobenzene precursors. The Pd-assisted C-C coupling methods were ineffective in the formation of the Ar-Ar bond except for the synthesis of 1b. All tet... |
14656079 | Analysis of conformational equilibria in aplidine using selective excitation 2D NMR spectroscopy and molecular mechanics/dynamics calculations. | Aplidine (dehydrodidemnin B), a natural product with potent antitumor activity currently in multicenter phase II clinical trials, exists in DMSO as a mixture of four slowly interconverting conformations in a ratio of 47:33:13:7. NMR spectroscopy shows that these arise as a consequence of cis/trans isomerization about t... |
14657186 | Distribution of postsynaptic density (PSD)-95 and Ca2+/calmodulin-dependent protein kinase II at the PSD. | Postsynaptic densities (PSDs) contain proteins that regulate synaptic transmission. We determined the positions of calcium/calmodulin-dependent protein kinase II (CaMKII) and PSD-95 within the three-dimensional structure of isolated PSDs using immunogold labeling, rotary shadowing, and electron microscopic tomography. ... |
14657168 | 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors protect cortical neurons from excitotoxicity. | 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase inhibitors, or statins, reduce the incidence of strokes and reduce infarct volume after cerebral ischemia in mice. Excitoxicity caused by overstimulation of glutamate receptors is a major cause of neuronal death after an ischemic brain insult. Experiments presented her... |
14657220 | Alveolar macrophage-mediated killing of Pneumocystis carinii f. sp. muris involves molecular recognition by the Dectin-1 beta-glucan receptor. | Innate immune mechanisms against Pneumocystis carinii, a frequent cause of pneumonia in immunocompromised individuals, are not well understood. Using both real time polymerase chain reaction as a measure of organism viability and fluorescent deconvolution microscopy, we show that nonopsonic phagocytosis of P. carinii b... |
14656972 | The clustered olfactory receptor gene family 262: genomic organization, promotor elements, and interacting transcription factors. | For six mouse olfactory receptor genes from family 262 which are expressed in clustered populations of olfactory sensory neurons, the genomic as well as cDNA structures were deciphered. All genes contained several exons which in some cases were alternatively spliced. Immediately upstream of the transcription start site... |
14570590 | Emerging and diverse roles of protein kinase C in immune cell signalling. | Members of the protein kinase C (PKC) family are expressed in many different cell types, where they are known to regulate a wide variety of cellular processes that impact on cell growth and differentiation, cytoskeletal remodelling and gene expression in the response to diverse stimuli. The broad tissue distribution an... |
12959641 | Oligomerization of the cardiac ryanodine receptor C-terminal tail. | The C-terminal 100 amino acids of the RyR (ryanodine receptor), referred to as the C-terminal tail, is a highly conserved sequence that is present in all known RyR isoforms and which has been implicated in channel function. Deleting the final 15 amino acids from the full-length skeletal muscle RyR resulted in an inacti... |
14654705 | The poly(A) binding protein Hfq protects RNA from RNase E and exoribonucleolytic degradation. | The Hfq protein, which shares sequence and structural homology with the Sm and Lsm proteins, binds to various RNAs, primarily recognizing AU-rich single-stranded regions. In this paper, we study the ability of the Escherichia coli Hfq protein to bind to a polyadenylated fragment of rpsO mRNA. Hfq exhibits a high specif... |
14654690 | The base pairing properties of 8-aza-7-deaza-2'-deoxyisoguanosine and 7-halogenated derivatives in oligonucleotide duplexes with parallel and antiparallel chain orientation. | The base pairing properties of oligonucleotide duplexes containing 8-aza-7-deaza-2'-deoxyisoguanosine, its 7-bromo or its 7-iodo derivative are described. The nucleosides were synthesized on a convergent route, protected and converted into phosphoramidites. Oligonucleotides were prepared on a solid-phase and were hybri... |
14654688 | Altered structural fluctuations in duplex RNA versus DNA: a conformational switch involving base pair opening. | DNA and RNA are known to have different structural properties. In the present study, molecular dynamics (MD) simulations on a series of RNA and DNA duplexes indicate differential structural flexibility for the two classes of oligonucleotides. In duplex RNA, multiple base pairs experienced local opening events into the ... |
14653749 | Water-mediated association provides an ion pair receptor. | In this paper, we report on the formation and properties of a water-stabilized dimer comprising calix[4]arene-guanosine conjugate cG 2. The 1,3-alternate calixarene cG 2 was poorly soluble in dry CDCl(3) and gave an ill-resolved NMR spectrum, consistent with its nonspecific aggregation. The compound was much more solub... |
14653748 | Hydrazide-based quadruply hydrogen-bonded heterodimers. Structure, assembling selectivity, and supramolecular substitution. | This paper describes the synthesis, self-assembly, and characterization of a new class of highly stable hydrazide-based quadruply hydrogen-bonded heterodimers. All of the hydrazide-derived heterodimers possess the complementary ADDA-DAAD hydrogen-bonding sequences. Hydrazide derivatives 1, which has two intramolecular ... |
14653744 | Hydrogen bonding interfaces in fullerene*TTF ensembles. | Novel thermodynamically stable supramolecular donor-acceptor dyads have been synthesized. In particular, we assembled successfully C(60), as an electron acceptor, with the strong electron donor TTF through a complementary guanidinium-carboxylate ion pair. Two strong and well-oriented hydrogen bonds, in combination with... |
14653738 | Crystal structures of two complexes of the rare-earth-DOTA-binding antibody 2D12.5: ligand generality from a chiral system. | We report the crystal structures of antibody 2D12.5 Fab bound to an yttrium-DOTA analogue and separately to a gadolinium-DOTA analogue. The rare earth elements have many useful properties as probes, and 2D12.5 binds the DOTA (1,4,7,10-tetraazacyclododecane-N,N',N' ',N' "-tetraacetic acid) complexes of all of them (Corn... |
14653716 | Self-assembled nanotubes that reversibly bind acetic acid guests. | A large bis-urea macrocycle was synthesized and assembled into columnar nanotubes containing a sizable cavity. This purely organic nanotube is held together primarily by hydrogen bonding and yet shows remarkable thermal stability up to 180 degrees C in the presence and absence of acetic acid guest. This enables the nan... |
14645541 | Organization of mammalian cytoplasm. | Although the role of macromolecular interactions in cell function has attracted considerable attention, important questions about the organization of cells remain. To help clarify this situation, we used a simple protocol that measures macromolecule release after gentle permeabilization for the examination of the statu... |
14645519 | Role played by microphthalmia transcription factor phosphorylation and its Zip domain in its transcriptional inhibition by PIAS3. | Mutation of microphthalmia transcription factor (MITF) results in deafness, bone loss, small eyes, and poorly pigmented eyes and skin. A search for MITF-associated proteins, using a mast cell library that was screened with a construct that encodes the basic helix-loop-helix leucine zipper (Zip) domain of MITF, resulted... |
14645511 | Mutation of a conserved hydrophobic patch prevents incorporation of ZP3 into the zona pellucida surrounding mouse eggs. | Three glycoproteins (ZP1, ZP2, and ZP3) are synthesized in growing mouse oocytes and secreted to form an extracellular zona pellucida that mediates sperm binding and fertilization. Each has a signal peptide to direct it into a secretory pathway, a "zona" domain implicated in matrix polymerization and a transmembrane do... |
14645595 | Sequence analysis of recent H7 avian influenza viruses associated with three different outbreaks in commercial poultry in the United States. | The hemagglutinin (HA) and neuraminidase (NA) genes of H7 avian influenza virus (AIV) isolated between 1994 and 2002 from live-bird markets (LBMs) in the northeastern United States and from three outbreaks in commercial poultry have been characterized. Phylogenetic analysis of the HA and NA genes demonstrates that the ... |
14645593 | Alpha interferon inhibits human T-cell leukemia virus type 1 assembly by preventing Gag interaction with rafts. | Alpha-2a interferon (IFN-alpha2a) has beneficial clinical effects on human T-cell leukemia virus type 1 (HTLV-1) infection, but its antiviral mechanism of action is unknown. Antiviral effects of IFN-alpha2a were studied in 293T cells expressing HTLV-1 proviral DNA and in HTLV-1-infected cells (HOS/PL, MT2, and HUT102).... |
14645580 | Signals that dictate nuclear localization of human papillomavirus type 16 oncoprotein E6 in living cells. | Human papillomavirus (HPV) type 16 E6 (16E6) is an oncogenic, multifunctional nuclear protein that induces p53 degradation and perturbs normal cell cycle control, leading to immortalization and transformation of infected keratinocytes and epithelial cells. Although it is unclear how 16E6 disrupts the epigenetic profile... |
14645577 | Infection and injury of neurons by West Nile encephalitis virus. | West Nile virus (WNV) infects neurons and leads to encephalitis, paralysis, and death in humans, animals, and birds. We investigated the mechanism by which neuronal injury occurs after WNV infection. Neurons in the anterior horn of the spinal cords of paralyzed mice exhibited a high degree of WNV infection, leukocyte i... |
14645565 | Barrier-to-autointegration factor BAF binds p55 Gag and matrix and is a host component of human immunodeficiency virus type 1 virions. | Barrier-to-autointegration factor (BAF) is a conserved human chromatin protein exploited by retroviruses. Previous investigators showed that BAF binds double-stranded DNA nonspecifically and is a host component of preintegration complexes (PICs) isolated from cells infected with human immunodeficiency virus type 1 (HIV... |
14645553 | Role of the cytoplasmic domain of the Newcastle disease virus fusion protein in association with lipid rafts. | To explore the association of the Newcastle disease virus (NDV) fusion (F) protein with cholesterol-rich membrane domains, its localization in detergent-resistant membranes (DRMs) in transfected cells was characterized. After solubilization of cells expressing the F protein with 1% Triton X-100 at 4 degrees C, ca. 40% ... |
14645551 | Stability and morphology comparisons of self-assembled virus-like particles from wild-type and mutant human hepatitis B virus capsid proteins. | Instead of displaying the wild-type selective export of virions containing mature genomes, human hepatitis B virus (HBV) mutant I97L, changing from an isoleucine to a leucine at amino acid 97 of HBV core antigen (HBcAg), lost the high stringency of selectivity in genome maturity during virion export. To understand the ... |
14645549 | Targeting of adenovirus via genetic modification of the viral capsid combined with a protein bridge. | A potential barrier to the development of genetically targeted adenovirus (Ad) vectors for cell-specific delivery of gene therapeutics lies in the fact that several types of targeting protein ligands require posttranslational modifications, such as the formation of disulfide bonds, which are not available to Ad capsid ... |
14643655 | The refined structure of a protein catenane: the HK97 bacteriophage capsid at 3.44 A resolution. | The HK97 bacteriophage capsid is a unique example of macromolecular catenanes: interlocked rings of covalently attached protein subunits. The chain mail organization of the subunits stabilizes a particle in which the maximum thickness of the protein shell is 18A and the maximum diameter is 550A. The electron density ha... |
14643252 | Morphological change of gold-dendrimer nanocomposites by laser irradiation. | Gold-dendrimer nanocomposites are prepared in aqueous solutions in the presence of poly(amidoamine)dendrimers (PAMAM) (generation 3 and 5) or poly(propyleneimine)dendrimers (PPI) (generation 3 and 4) by wet chemical NaBH(4) method. Thus prepared gold-dendrimer nanocomposites are irradiated by laser at 532 nm. UV-vis ab... |
14643500 | Chromatographic determination of the association constant between 8-methoxypsoralen and modified beta-cyclodextrin: protective effect of hydroxypropyl-beta-cyclodextrin on 8-methoxypsoralen toxicity in human keratinocytes. | The retention of 8-methoxypsoralen (8-MOP) on an immobilised hydroxypropyl-beta-cyclodextrin (HP-beta-CD) column was analysed in HPLC by the determination of its Langmuir distribution isotherm. A such method was used to confirm the potential drug complexing role of this cyclodextrin. The 8-MOP/HP-beta-CD association co... |
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