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15583033 | Neuronal membrane cholesterol loss enhances amyloid peptide generation. | Recent experimental and clinical retrospective studies support the view that reduction of brain cholesterol protects against Alzheimer's disease (AD). However, genetic and pharmacological evidence indicates that low brain cholesterol leads to neurodegeneration. This apparent contradiction prompted us to analyze the rol... |
15583031 | Vesicles carry most exocyst subunits to exocytic sites marked by the remaining two subunits, Sec3p and Exo70p. | Exocytosis in the budding yeast Saccharomyces cerevisiae occurs at discrete domains of the plasma membrane. The protein complex that tethers incoming vesicles to sites of secretion is known as the exocyst. We have used photobleaching recovery experiments to characterize the dynamic behavior of the eight subunits that m... |
15582521 | A proteomic analysis of malaria biology: integration of old literature and new technologies. | The genomic revolution has brought a new vitality into research on Plasmodium, its insect and vertebrate hosts. At the cellular level nowhere is the impact greater than in the analysis of protein expression and the 'assembly' of the supramolecular machines that together comprise the functional cell. The repetitive phas... |
15582795 | Quantum dots and other nanoparticles: what can they offer to drug discovery? | Nanocrystals (quantum dots) and other nanoparticles (gold colloids, magnetic bars, nanobars, dendrimers and nanoshells) have been receiving a lot of attention recently with their unique properties for potential use in drug discovery, bioengineering and therapeutics. In this review, structural, optical and biological as... |
15581420 | The problem of amino acid complementarity and antisense peptides. | The review presents three hypotheses concerning the amino acid complementarity: 1) the Mekler-Blalock antisense hypothesis; 2) the Root-Bernstein approach based on stereochemical complementarity of amino acids and anti-amino acids coded by anticodons read in parallel with the coding DNA strand; 3) Siemion hypothesis re... |
15582399 | Structural aspects of non-ribosomal peptide biosynthesis. | Small peptides have powerful biological activities ranging from antibiotic to immune suppression. These peptides are synthesized by non-ribosomal peptide synthetases (NRPS). Structural understanding of NRPS took a huge leap forward in 2002; this information has led to several detailed biochemical studies and further st... |
15583867 | Neurofilament proteins in neurodegenerative diseases. | The function of neurofilaments, the major component in large myelinated neurons, is not well understood even though they were discovered as structures over 100 years ago. Recent studies have suggested that neuro-filaments are closely related to many neurodegenerative diseases, such as amyotrophic lateral sclerosis, Par... |
15583866 | The role of the trans-Golgi network in varicella zoster virus biology. | The task of assembling nascent virions presents a formidable challenge to large, enveloped DNA viruses such as varicella zoster virus (VZV). After parasitising the host cell's compartmentalised biosynthetic machinery, viral constituents must be brought together in appropriate proportions for packaging and export. Recen... |
15583865 | Directed evolution of enzymes for biocatalysis and the life sciences. | Engineering the specificity and properties of enzymes and proteins within rapid time frames has become feasible with the advent of directed evolution. In the absence of detailed structural and mechanistic information, new functions can be engineered by introducing and recombining mutations, followed by subsequent testi... |
15581861 | Membrane cholesterol content modulates activation of BK channels in colonic epithelia. | Changes in the level of membrane cholesterol regulate a variety of signaling processes including those mediated by acylated signaling molecules that localize to lipid rafts. Recently several types of ion channels have been shown to have cholesterol-dependent activity and to localize to lipid rafts. In this study, we ha... |
15581374 | Membrane translocation mechanism of the antimicrobial peptide buforin 2. | The antimicrobial peptide magainin 2 isolated from the skin of the African clawed frog Xenopus laevis crosses lipid bilayers by transiently forming a peptide-lipid supramolecular complex pore inducing membrane permeabilization and flip-flop of membrane lipids [Matsuzaki, K., Murase, O., Fujii, N., and Miyajima, K. (199... |
15581356 | Synchronized conformational fluctuations and binding site desolvation during molecular recognition. | Binding site desolvation is a poorly understood prerequisite to ligand binding. Although structural fluctuations may be expected to have an important role, little is known about which fluctuations are important or the mechanism by which they promote desolvation. This investigation examines whether and how specific stru... |
15581551 | Dispersions of polymer ionomers: I. | The principal subject discussed in the current paper is the effect of ionic functional groups in polymers on the formation of nontraditional polymer materials, polymer blends or polymer dispersions. Ionomers are polymers that have a small amount of ionic groups distributed along a nonionic hydrocarbon chain. Specific i... |
15579117 | Effect of cyclodextrin on the activity and secondary structure of horseradish peroxidase. | The activity and secondary structure of horseradish peroxidase (HRP) was studied in aqueous solution containing alpha-, beta- and gamma-cyclodextrin (CD). The results showed that the activity of HRP was enhanced to different extents by the three kinds of CD. A Fourier Transform infrared (FTIR) spectroscopy study indica... |
15579116 | Synthetic approaches to the 2003 new drugs. | New drugs are introduced to the market every year and each individual drug represents a privileged structure for its biological target. In addition, these new chemical entities (NCEs) not only provide insights into molecular recognition, but also serve as drug-like leads for designing new future drugs. To these ends, t... |
15578852 | Preparation, structure characterization, and oxidation activity of ruthenium complexes with tripodal ligands bearing noncovalent interaction sites. | Ruthenium(II/III) complexes with tripodal tris(pyridylmethyl)amine ligands bearing one, two, or three pivalamide groups (MPPA, BPPA, TPPA: amide-series ligands) or neopentylamine ones (MNPA, BNPA, TNPA: amine-series ligands) at the 6-position of the pyridine ring have been synthesized and structurally characterized. Th... |
15579043 | Dendrimer-based nanosized MRI contrast agents. | Paramagnetic metals can induce T1 shortening by interaction with free water molecules. Two metal ions, Gadolinium and Manganese, are currently available for human use. Gadolinium-based MRI contrast agents (CAs) can operate using a approximately 100-fold lower concentration of Gadolinium ions in comparison to the necess... |
15579040 | Targeting cells with MR imaging probes based on paramagnetic Gd(III) chelates. | The low sensitivity is the major disadvantage of MRI as compared to PET. Therefore, amplification strategies are necessary for specific pathway labeling. This survey is aimed at exploring different routes to the entrapment of Gd(III) chelates in various type of cells at amounts sufficiently large to allow MRI visualiza... |
15579000 | Dendrotoxins: structure-activity relationships and effects on potassium ion channels. | Dendrotoxins are small proteins isolated from mamba (Dendroaspis) snakes. The original dendrotoxin was found in venom of the Eastern green mamba, Dendroaspis angusticeps, and related proteins were subsequently found in other mamba venoms. The dendrotoxins contain 57-60 amino acid residues cross-linked by three disulphi... |
15578935 | Anti-endotoxin agents. 2. Pilot high-throughput screening for novel lipopolysaccharide-recognizing motifs in small molecules. | Lipopolysaccharides (LPS), otherwise termed 'endotoxins', are an integral part of the outer leaflet of the outer-membrane of Gram-negative bacteria. Lipopolysaccharides play a pivotal role in the pathogenesis of 'Septic Shock', a major cause of mortality in the critically ill patient, worldwide. The sequestration of ci... |
15577263 | [Pharmaceutical application of cyclodextrins as multi-functional drug carriers]. | Owing to the increasingly globalized nature of the cyclodextrin (CyD)-related science and technology, development of the CyD-based pharmaceutical formulation is rapidly progressing. The pharmaceutically useful CyDs are classified into hydrophilic, hydrophobic, and ionic derivatives. Because of the multi-functional char... |
15575672 | Highly efficient two-step synthesis of C-sp3-centered geminal diiodides. | [reaction: see text] Trisubstituted gem-diiodoalkenes of functionalized chains are efficiently reduced to the corresponding terminal geminal diiodides in high yields upon treatment with the diazene precursor, diethyl 4-(hydrazinosulfonyl)-benzyl phosphonate. |
15575656 | Novel pi-expanded radialene macrocycles with inner cavity. | [structure: see text] Polyenyne macrocycles with pi-extended [9]- and [12]radialene frameworks have been synthesized. These radialenes exhibit restricted rotation of the aromatic rings, and the D3- and D4-symmetric structures in solutions have been determined by dynamic NMR. The macrocyclic radialenes bear small to med... |
15575779 | Synthesis of nitrogen-functionalized beta-cycloaltrins. | We report the synthesis of functionalized beta-cycloaltrins having azido groups at C-3, C-6, and both C-3 and C-6 by nucleophilic epoxy ring-opening of per-2,3-anhidro-beta-cyclomannin derivatives. The value of these compounds as templates for further functionalization is exemplified by the conversion of heptakis(3,6-d... |
15575751 | Mild and selective reduction of imines: formation of an unsymmetrical macrocycle. | During investigations of 5, a [3 + 3] Schiff-base macrocycle with six imines, a partially reduced Schiff-base macrocycle, 6, possessing one CH(2)NH and five imine groups was obtained. Control experiments and deuterium labeling indicate that the macrocycle is reduced by a benzimidazoline generated during the reaction. B... |
15575736 | Reversible chemistry of CO2 in the preparation of fluorescent supramolecular polymers. | The chemistry between CO(2) and primary amines was used to construct novel types of supramolecular polymers and networks. Fluorescent self-assembling gel 2 was prepared, which employs both hydrogen bonding and dynamic, thermally reversible carbamate bonds. As precursors, biscalixarenes 1, 3, 4, 6, and 7 were synthesize... |
15576786 | In vivo bypass of chaperone by extended coiled-coil motif in T4 tail fiber. | The distal-half tail fiber of bacteriophage T4 is made of three gene products: trimeric gp36 and gp37 and monomeric gp35. Chaperone P38 is normally required for folding gp37 peptides into a P37 trimer; however, a temperature-sensitive mutation in T4 (ts3813) that suppresses this requirement at 30 degrees C but not at 4... |
15577853 | Increased noncanonical splicing of autoantigen transcripts provides the structural basis for expression of untolerized epitopes. | <h4>Background</h4>Alternative splicing is important for increasing the complexity of the human proteome from a limited genome. Previous studies have shown that for some autoantigens, there is differential immunogenicity among alternatively spliced isoforms.<h4>Objectives</h4>Herein, we tested the hypothesis that alter... |
15576490 | Obesity-related leptin regulates Alzheimer's Abeta. | Abeta peptide is the major proteinateous component of the amyloid plaques found in the brains of Alzheimer's disease (AD) patients and is regarded by many as the culprit of the disorder. It is well documented that brain lipids are intricately involved in Abeta-related pathogenic pathways. An important modulator of lipi... |
15577926 | Always look on the bright site of Rho: structural implications for a conserved intermolecular interface. | The signalling functions of Rho-family GTPases are based on the formation of distinctive protein-protein complexes. Invaluable insights into the structure-function relationships of the Rho GTPases have been obtained through the resolution of several of their structures in complex with regulators and downstream effector... |
15577234 | Interaction of heptakis (2,3,6-tri-O-methyl)-beta-cyclodextrin with cholesterol in aqueous solution. | The interaction of cholesterol with heptakis (2,3,6-tri-O-methyl)-beta-cyclodextrin (TOM-beta-CyD) was investigated in water using solubility method. It was found that TOM-beta-CyD forms two kinds of soluble complexes, with molar ratios of 1:1 and 1:2 (cholesterol:TOM-beta-CyD). The thermodynamic parameters for 1:1 and... |
15574598 | Su(var) genes regulate the balance between euchromatin and heterochromatin in Drosophila. | Histone lysine methylation is an epigenetic mark to index chromosomal subdomains. In Drosophila, H3-K9 di- and trimethylation is mainly controlled by the heterochromatic SU(VAR)3-9 HMTase, a major regulator of position-effect variegation (PEV). In contrast, H3-K27 methylation states are independently mediated by the Pc... |
15461589 | Exploitation of KESTREL to identify NDRG family members as physiological substrates for SGK1 and GSK3. | We detected a protein in rabbit skeletal muscle extracts that was phosphorylated rapidly by SGK1 (serum- and glucocorticoid-induced kinase 1), but not by protein kinase Ba, and identified it as NDRG2 (N-myc downstream-regulated gene 2). SGK1 phosphorylated NDRG2 at Thr330, Ser332 and Thr348 in vitro. All three residues... |
15574921 | Characterization of a novel amylolytic enzyme encoded by a gene from a soil-derived metagenomic library. | It has been estimated that less than 1% of the microorganisms in nature can be cultivated by conventional techniques. Thus, the classical approach of isolating enzymes from pure cultures allows the analysis of only a subset of the total naturally occurring microbiota in environmental samples enriched in microorganisms.... |
15573101 | Cyclodextrin-based pharmaceutics: past, present and future. | Cyclodextrins are cyclic oligomers of glucose that can form water-soluble inclusion complexes with small molecules and portions of large compounds. These biocompatible, cyclic oligosaccharides do not elicit immune responses and have low toxicities in animals and humans. Cyclodextrins are used in pharmaceutical applicat... |
15572693 | PRAM-1 is required for optimal integrin-dependent neutrophil function. | PML-retinoic acid receptor alpha (RARalpha) regulated adaptor molecule 1 (PRAM-1) is an intracellular adaptor molecule that is upregulated during the induced granulocytic differentiation of promyelocytic leukemic cells and during normal human myelopoiesis. This report describes the generation of PRAM-1-deficient mice a... |
15571397 | Synthetic ion channel activity documented by electrophysiological methods in living cells. | Hydraphiles are synthetic ion channels that use crown ethers as entry portals and that span phospholipid bilayer membranes. Proton and sodium cation transport by these compounds has been demonstrated in liposomes and planar bilayers. In the present work, whole cell patch clamp experiments show that hydraphiles integrat... |
15571376 | A strong positive dendritic effect in a peptide dendrimer-catalyzed ester hydrolysis reaction. | The contribution of the dendritic structure in catalysis of ester hydrolysis was investigated with a systematic peptide dendrimer series of increasing generation number (G1-G4) containing a catalytic consensus sequence His-Ser in all branches. A strong positive dendritic effect was observed with up to 100-fold increase... |
15571373 | Dendrimers with both polar and apolar nanocontainer characteristics. | Amphiphilic dendrimers with a custom-designed biaryl repeat unit have been synthesized. These dendrimers afford hydrophobic nanocontainers in polar solvents and hydrophilic nanocontainers in apolar solvents. These container properties were investigated using dye incorporation studies. The aggregation states of these de... |
15568833 | Solvent effects on supramolecular gel-phase materials: two-component dendritic gel. | The self-assembly of diaminododecane with dendritic l-lysine-based peptides to form gel-phase materials was investigated in a range of different solvents. The degree of structuring was modulated by the solvent employed, an effect which induced subtle changes in the mesoscale aggregate morphology and macroscopic behavio... |
15558739 | Sidechain biology and the immunogenicity of PDC-E2, the major autoantigen of primary biliary cirrhosis. | The E2 component of mitochondrial pyruvate dehydrogenase complex (PDC-E2) is the immunodominant autoantigen of primary biliary cirrhosis. Whereas lipoylation of PDC-E2 is essential for enzymatic activity and predominates under normal conditions, other biochemical systems exist that also target the lysine residue, inclu... |
15567494 | Assembly and budding of influenza virus. | Influenza viruses are causative agents of an acute febrile respiratory disease called influenza (commonly known as "flu") and belong to the Orthomyxoviridae family. These viruses possess segmented, negative stranded RNA genomes (vRNA) and are enveloped, usually spherical and bud from the plasma membrane (more specifica... |
15564499 | Inhibition of parainfluenza virus type 3 and Newcastle disease virus hemagglutinin-neuraminidase receptor binding: effect of receptor avidity and steric hindrance at the inhibitor binding sites. | Zanamivir (4-guanidino-Neu5Ac2en [4-GU-DANA]) inhibits not only the neuraminidase activity but also the receptor interaction of the human parainfluenza virus type 3 (HPIV3) hemagglutinin-neuraminidase (HN), blocking receptor binding and subsequent fusion promotion. All activities of the HPIV3 variant ZM1 HN (T193I/I567... |
15564476 | Oligomerization of Hantavirus N protein: C-terminal alpha-helices interact to form a shared hydrophobic space. | The structure of the nucleocapsid protein of bunyaviruses has not been defined. Earlier we have shown that Tula hantavirus N protein oligomerization is dependent on the C-terminal domains. Of them, the helix-loop-helix motif was found to be an essential structure. Computer modeling predicted that oligomerization occurs... |
15564460 | Two different molecular defects in the Tva receptor gene explain the resistance of two tvar lines of chickens to infection by subgroup A avian sarcoma and leukosis viruses. | The subgroup A to E avian sarcoma and leukosis viruses (ASLVs) are highly related and are thought to have evolved from a common ancestor. These viruses use distinct cell surface proteins as receptors to gain entry into avian cells. Chickens have evolved resistance to infection by the ASLVs. We have identified the mutat... |
15564450 | Identification of a naturally processed cytotoxic CD8 T-cell epitope of coxsackievirus B4, presented by HLA-A2.1 and located in the PEVKEK region of the P2C nonstructural protein. | The adaptive immune system generates CD8 cytotoxic T lymphocytes (CTLs) as a major component of the protective response against viruses. Knowledge regarding the nature of the peptide sequences presented by HLA class I molecules and recognized by CTLs is thus important for understanding host-pathogen interactions. In th... |
15563188 | Bimetallic palladium-gold dendrimer-encapsulated catalysts. | The synthesis, characterization, and catalytic properties of 1-3 nm-diameter bimetallic PdAu dendrimer-encapsulated catalysts are reported. Both alloy and core/shell PdAu nanoparticles were prepared. The catalytic hydrogenation of allyl alcohol was significantly enhanced in the presence of the alloy and core/shell PdAu... |
15563181 | Electromechanics of a redox-active rotaxane in a monolayer assembly on an electrode. | A rotaxane monolayer consisting of the cyclophane, cyclobis(paraquat-p-phenylene) (2), threaded on a "molecular string" that includes a pi-donor diiminobenzene unit and stoppered by an adamantane unit is assembled on a Au electrode. The surface coverage of the electroactive cyclophane unit, E degrees = -0.43 V vs SCE, ... |
15563180 | Dynamics of alkoxy-oligothiophene ground and excited states in nanochannels. | Two oligothiophenes, 4,4'-dipentoxy-2,2'-dithiophene and 4,4"-dipentoxy-2,2':5',2":5",2' ''-tetrathiophene, have been included in the nanochannels of the autoassembling host TPP (tris-o-phenylenedioxycyclotriphosphazene). The effect of the confinement on the structure and properties of the two dyes, as conformational a... |
15563168 | A general and high yielding fragment coupling synthesis of heteroatom-bridged calixarenes and the unprecedented examples of calixarene cavity fine-tuned by bridging heteroatoms. | A number of aza- and/or oxo-bridged calix[2]arene[2]triazines have been synthesized through an unusually high yielding and efficient fragment coupling approach starting from cyanuric chloride and resorcinol, 3-aminophenol, m-phenylenediamine, and N,N'-dimethyl-m-phenylenediamine. These novel macrocycles, which belong t... |
15563148 | Heterocyclic peptide backbone modifications in an alpha-helical coiled coil. | In this paper, we present 1,2,3-triazole epsilon2-amino acids incorporated as a dipeptide surrogate at three positions in the sequence of a known alpha-helical coiled coil. Biophysical characterization indicates that the modified peptides retain much of the helical structure of the parent sequence, and that the thermod... |
15563147 | Anion-templated assembly of a [2]catenane. | The first example of a [2]catenane structure to be synthesized using anion templation is described. The nature of the anion template is demonstrated to be crucial to the assembly process, with only chloride anion producing the [2]catenane in acceptable yield. Anion binding studies reveal a dramatic catenation effect on... |
15560989 | Novel forms of chemical protein diversity -- in nature and in the laboratory. | Novel chemical variants of proteins have been found in nature, including potent 'microprotein' natural products and folded protein molecules that contain a cyclic polypeptide chain. Researchers have used chemical synthesis and genetic methods to make these proteins and more: protein catenanes, neoglycoproteins, and art... |
15551269 | Insulin and its receptor: structure, function and evolution. | I present here a personal perspective on more than three decades of research into the structural biology of the insulin-receptor interaction. The solution of the three-dimensional structure of insulin in 1969 provided a detailed understanding of the insulin surfaces involved in self-assembly. In subsequent years, hundr... |
15561872 | VanE-type vancomycin-resistant Enterococcus faecalis clinical isolates from Australia. | Three distinct Enterococcus faecalis VanE-type isolates-BM4574, BM4575, and BM4576-obtained in Australia were studied. Expression of the resistance genes was constitutive in BM4575, probably due to a 2-bp deletion into the vanSE gene, and inducible in BM4574 and BM4576. Transcription analysis of the vanE operons sugges... |
15561861 | Novel nonnucleoside inhibitor of hepatitis C virus RNA-dependent RNA polymerase. | A novel nonnucleoside inhibitor of hepatitis C virus (HCV) RNA-dependent RNA polymerase (RdRp), [(1R)-5-cyano-8-methyl-1-propyl-1,3,4,9-tetrahydropyano[3,4-b]indol-1-yl] acetic acid (HCV-371), was discovered through high-throughput screening followed by chemical optimization. HCV-371 displayed broad inhibitory activiti... |
15557258 | Solvation and the hidden thermodynamics of a zinc finger probed by nonstandard repair of a protein crevice. | The classical Zn finger contains a phenylalanine at the crux of its three architectural elements: a beta-hairpin, an alpha-helix, and a Zn(2+)-binding site. Surprisingly, phenylalanine is not required for high-affinity Zn2+ binding, but instead contributes to the specification of a precise DNA-binding surface. Substitu... |
15556511 | Current chemical tagging strategies for proteome analysis by mass spectrometry. | Proteomics, the analysis of the protein complement of a cell or an organism, has grown rapidly as a subdiscipline of the life sciences. Mass spectrometry (MS) is one of the central detection techniques in proteome analysis, yet it has to rely on prior sample preparation steps that reduce the enormous complexity of the ... |
15556495 | Separation methods for pharmacologically active xanthones. | Xanthones, as a kind of polyphenolic natural products with many strong bioactivities, are attractive for separation scientists due to the similarity and diversity of their structures resulting in difficult separation by chromatographic methods. High performance liquid chromatography (HPLC) and thin layer chromatography... |
15557670 | Lipid raft-mediated entry is not required for Chlamydia trachomatis infection of cultured epithelial cells. | Using pharmacologic and biochemical criteria, we evaluated whether uptake of four different Chlamydia trachomatis serovars, D, E, K, and L2, was dependent upon lipid rafts. Our data suggest that lipid raft-mediated entry is not required for C. trachomatis infection of cultured epithelial cells. |
15557650 | Transcriptional profiling of lipopolysaccharide-induced acute lung injury. | Mortality associated with acute lung injury (ALI) induced by lipopolysaccharide (LPS) remains high in humans, warranting improved treatment and prevention strategies. ALI is characterized by the expression of proinflammatory mediators and extensive neutrophil influx into the lung, followed by severe lung damage. Unders... |
15554924 | Major histocompatibility complex class I-intercellular adhesion molecule-1 association on the surface of target cells: implications for antigen presentation to cytotoxic T lymphocytes. | Polarization and segregation of the T-cell receptor (TCR) and integrins upon productive cytotoxic T-lymphocyte (CTL) target cell encounters are well documented. Much less is known about the redistribution of major histocompatibility complex class I (MHC-I) and intercellular adhesion molecule-1 (ICAM-1) proteins on targ... |
15556409 | Peptide self-assembly as a model of proteins in the pre-genomic world. | Excellent catalytic efficiency has been obtained within a series of self replicating peptides, and nucleobase inclusion into a salt-switchable self replicating peptide is found to override the switch. Interestingly, cross-catalytic formation of an RNA aptamer is reported with a cationic peptide, and novel, amide-based ... |
15556403 | Covalent capture: a natural complement to self-assembly. | The utility of peptide self-assembly can be extended by covalent capture of these supramolecular materials. Disulfide bond formation, native chemical ligation, olefin metathesis, radical capture and oxidative lysine cross-linking have been used recently to help stabilize and characterize a variety of self-assembled pep... |
15556402 | Self-assembly of reactive amphiphilic block copolymers as mimetics for biological membranes. | Over the years, polymers have attracted a great deal of interest because they offer a unique platform for the development of materials in fields as diverse as biomedicine and packaging. Many of these purposes use polymers that had been developed for totally different applications. Recently, however, chemical tailoring ... |
15556373 | Towards the design of host-guest complexes: biotin and urea derivatives versus artificial receptors. | Molecular mechanics calculations (Macromodel v.5.0 and v.8.1) have been used in order to correlate the minimized energies of the complexes with the binding constant Kb values measured on two hosts and five urea derivatives including methyl biotin. Kb values obtained by means of NMR titrations, in the right concentratio... |
15556365 | A molecular recognition strategy towards tetra-chlorinated dibenzo-p-dioxins, TCDDs. | Uniformly sized polymeric separation media were prepared using o- or p-xylene as porogenic template to investigate chromatographic selectivity towards tetra-chlorinated dibenzo-p-dioxins (TCDDs). TCDDs having chlorine atoms at ortho positions of phenyl rings were selectively retained on stationary phase prepared with o... |
15556364 | Sorption of amines by the Langmuir-Blodgett films of soluble cobalt phthalocyanines: evidence for the supramolecular mechanisms. | By means of microgravimetry, UV-Vis spectroscopy and optic microscopy, sorption of pyridine, primary aliphatic amines and benzylamine by the Langmuir-Blodgett (LB) films of tetra-4-tert-butyl- and tetra-(3-nitro-5-tert-butyl)-substituted cobalt phthalocyanines (CoPc' and CoPc*, respectively) was studied over a broad co... |
15556348 | The interaction of azacrown ether with fatty acid in nonpolar solvents and at the organic-aqueous interface. | In the paper, we show that lipophilic azacrown ether (22DD) in solvents of low to intermediate polarity forms the complexes with fatty acids, like lauric or palmitic acid. Due to the weak acid-base properties of the azacrown ether-fatty acid system, no proton transfer between the two molecules was observed, as shown by... |
15554935 | Factors associated with urea reduction ratio in acute renal failure. | Prescription and delivery of hemodialysis (HD) in acute renal failure (ARF) may be affected by patient-related factors such as hemodynamic instability, catabolism, variable extracellular fluid volume, and coagulation disturbances. This study was undertaken in a cohort of patients with ARF requiring HD, to quantify pati... |
15549949 | Surface-enhanced Raman scattering from ordered Ag nanocluster arrays. | We have examined the effect of ordered silver nanocluster substrates on the surface-enhanced Raman spectrum of rhodamine 6G (R6G). Triangular shaped silver nanocluster arrays with order on the approximately 100 mum range were prepared using nanosphere lithography. Direct comparisons of R6G surface-enhanced Raman spectr... |
15450003 | The protein structures that shape caspase activity, specificity, activation and inhibition. | The death morphology commonly known as apoptosis results from a post-translational pathway driven largely by specific limited proteolysis. In the last decade the structural basis for apoptosis regulation has moved from nothing to 'quite good', and we now know the fundamental structures of examples from the initiator ph... |
15324300 | Efficient production of active chicken avidin using a bacterial signal peptide in Escherichia coli. | Chicken avidin is a highly popular tool with countless applications in the life sciences. In the present study, an efficient method for producing avidin protein in the periplasmic space of Escherichia coli in the active form is described. Avidin was produced by replacing the native signal sequence of the protein with a... |
15287848 | Kinetic and structural optimization to catalysis at low temperatures in a psychrophilic cellulase from the Antarctic bacterium Pseudoalteromonas haloplanktis. | The cold-adapted cellulase CelG has been purified from the culture supernatant of the Antarctic bacterium Pseudoalteromonas haloplanktis and the gene coding for this enzyme has been cloned, sequenced and expressed in Escherichia coli. This cellulase is composed of three structurally and functionally distinct regions: a... |
15499567 | Generalized Poland-Scheraga model for DNA hybridization. | The Poland-Scheraga (PS) model for the helix-coil transition of DNA considers the statistical mechanics of the binding (or hybridization) of two complementary strands of DNA of equal length, with the restriction that only bases with the same index along the strands are allowed to bind. In this article, we extend this m... |
15547275 | Effector-mediated interaction of CbbRI and CbbRII regulators with target sequences in Rhodobacter capsulatus. | In Rhodobacter capsulatus, genes encoding enzymes of the Calvin-Benson-Bassham reductive pentose phosphate pathway are located in the cbb(I) and cbb(II) operons. Each operon contains a divergently transcribed LysR-type transcriptional activator (CbbR(I) and CbbR(II)) that regulates the expression of its cognate cbb pro... |
15547264 | Global transposon mutagenesis and essential gene analysis of Helicobacter pylori. | We have constructed a genome-saturating mutant library of the human gastric pathogen Helicobacter pylori. Microarray tracking of transposon mutants (MATT) allowed us to map the position of 5,363 transposon mutants in our library. While we generally found insertions well distributed throughout the genome, 344 genes had ... |
15544801 | Highly ordered supra-molecular organization of the mycobacterial lipoarabinomannans in solution. Evidence of a relationship between supra-molecular organization and biological activity. | The complex mycobacterial mannosylated lipoarabinomannans (ManLAMs) are currently considered to be the major virulence factors of the pathogenic Mycobacterium tuberculosis. The recognition and the interaction of ManLAMs with immune system receptors have been shown to promote M.tuberculosis phagocytosis but also to down... |
15542679 | Structural requirements of astrovirus virus-like particles assembled in insect cells. | Expression of the complete ORF2 of human astrovirus serotype 1 (HAstV-1) in the baculovirus system led to the formation of virus-like particles (VLPs) of around 38 nm. The same kind of VLPs were also obtained either with the expression of a truncated form of ORF2 lacking the first 70 amino acids (aa), or with the same ... |
15542644 | Epitope determinants of a chimpanzee Fab antibody that efficiently cross-neutralizes dengue type 1 and type 2 viruses map to inside and in close proximity to fusion loop of the dengue type 2 virus envelope glycoprotein. | The epitope determinants of chimpanzee Fab antibody 1A5, which have been shown to be broadly reactive to flaviviruses and efficient for cross-neutralization of dengue virus type 1 and type 2 (DENV-1 and DENV-2), were studied by analysis of DENV-2 antigenic variants. Sequence analysis showed that one antigenic variant c... |
15542641 | Requirement of Sur2 for efficient replication of mouse adenovirus type 1. | Mouse adenovirus type 1 (MAV-1) early region 1A (E1A) encodes a virulence gene in viral infection of mice. To broaden our understanding of the functions of E1A in MAV-1 pathogenesis, an unbiased experimental approach, glutathione S-transferase (GST) pulldown, was used to screen for cellular proteins that interact with ... |
15541916 | Enteric-coated layered double hydroxides as a controlled release drug delivery system. | Layered double hydroxides (LDHs) or so-called anionic clays consist of cationic brucite-like layers and exchangeable interlayer anions. Because of their biocompatibility, these layered inorganic solids can be used as host materials to create drug-LDH host-guest supramolecular structures. Because of the basicity of LDHs... |
15542511 | Acetylated sialic acid residues and blood group antigens localise within the epithelium in microvillous atrophy indicating internal accumulation of the glycocalyx. | <h4>Background</h4>Microvillous atrophy, a disorder of intractable diarrhoea in infancy, is characterised by the intestinal epithelial cell abnormalities of abnormal accumulation of periodic acid-Schiff (PAS) positive secretory granules within the apical cytoplasm and the presence of microvillous inclusions. The identi... |
15542089 | Structure and stability of columnar cyclomaltohexaose (alpha-cyclodextrin) hydrate. | Rapid recrystallization of cyclomaltohexaose (alpha-cyclodextrin, alpha-CD) from aqueous solution resulted in formation of the columnar crystal structure of alpha-CD containing only water as the guest molecule. Complementary water vapor sorption and wide-angle X-ray diffractometry (WAXD) experiments were performed on t... |
15542087 | In vitro enzymatic modification of puerarin to puerarin glycosides by maltogenic amylase. | Puerarin (daidzein 8-C-glucoside), the most abundant isoflavone in Puerariae radix, is prescribed to treat coronary heart disease, cardiac infarction, problems in ocular blood flow, sudden deafness, and alcoholism. However, puerarin cannot be given by injection due to its low solubility in water. To increase its solubi... |
15541053 | Correlation between tyrosine phosphorylation intensity of a 107 kDa protein band and A23187-induced acrosome reaction in human spermatozoa. | This study, performed using semen samples from 10 men, investigated the relationship between sperm protein tyrosine phosphorylation and acrosomal status in conditions supporting in vitro capacitation. Percoll-selected spermatozoa (cells from the 95% fraction) were incubated for 3 h at 37 degrees C under an atmosphere o... |
15539362 | Soap and sand: construction tools for nanotechnology. | Nanotechnology is the science of making and using very small structures. As the scales of the constructions become smaller, the existing methods of making these structures--lithography, etching and micromoulding--although constantly improving, will reach physical limits. To overcome the limitations and create smaller, ... |
15534918 | Dynamic changes in the expression of matrix metalloproteinases and their inhibitors, TIMPs, during hepatic fibrosis induced by alcohol in rats. | <h4>Aim</h4>To determine the dynamic changes in the expression of matrix metalloproteinases (MMPs) and the endogenous tissue inhibitors of MMPs inhibitors (TIMPs) during hepatic fibrosis induced by alcohol.<h4>Methods</h4>Male Sprague-Dawley rats were randomly divided into normal, 4 d, 2 wk, 4 wk, 9 wk and 11 wk groups... |
15533420 | Electrochemical properties of protoporphyrin IX zinc(II) films. | The electrochemical properties of protoporphyrin IX zinc(II) (ZnPP) films on indium-tin oxide (ITO) substrate have been studied for three types of films with different arrangements, which were an adsorbed film of ZnPP and LB films of ZnPP and its hybrid with hexadecyltrimethylammonium bromide. Cyclic voltammetry (CV) m... |
15515180 | Thyroxine revisited. | The crystal structure of the common therapeutic agent, the pentahydrated sodium salt of L-thyroxine hormone (3-[4-(4-hydroxy-3,5-diiodophenoxy)-3,5-diiodophenyl]-L-alanine), has been determined and discussed in relation to the drug's stability. The stoichiometry and absolute configuration (-)-C(8)S-[C15H10I4NO4]-.Na+.5... |
15514924 | Structural characterization and enantioseparation of the chiral compound praziquantel. | In this study, we aimed to characterize the chiral compound type of a leading antischistosomal drug, praziquantel. The optically pure praziquantel enantiomers were recovered from the racemic mixture by enantiomeric separation, which was performed on preparative scale chromatography by using a novel beta-cyclodextrin ty... |
15459947 | Kinetics and mechanism of degradation of epothilone-D: an experimental anticancer agent. | The objective of this study was to investigate the stability and the degradation pathway of epothilone-D (Epo-D), an experimental anticancer agent. In pH range 4-9, Epo-D displayed pH-independent stability and the highest stability was observed at pH 1.5-2 where its thiazole group is protonated. Increasing the pH >9 or... |
15468065 | Protein conformational transitions coupled to binding in molecular recognition of unstructured proteins: hierarchy of structural loss from all-atom Monte Carlo simulations of p27Kip1 unfolding-unbinding and structural determinants of the binding mechanism. | Conformational transitions coupled to binding are studied for the p27(Kip1) protein which undergoes a functional disorder-to-order folding transition during tertiary complex formation with the phosphorylated cyclin A-cyclin-dependent kinase 2 (Cdk2) binary complex. Temperature-induced Monte Carlo simulations of p27(Kip... |
15457436 | Gelation of gellan gum aqueous solutions studied by polarization modulation spectroscopy. | Circular birefringence (CB, or optical rotation) and linear birefringence (LB) were measured for gellan gum aqueous solutions with and without salt to examine the gelling system in the helical structure as well as in the orientation. It was found that gelling samples with salt show nonzero LB values, whereas LB is zero... |
15522688 | The effect of polyamidoamine dendrimers on human erythrocyte membrane acetylcholinesterase activity. | Polyamidoamine (PAMAM) dendrimers impact on activity of acetylcholinesterase was studied. It has been shown that dendrimers induce a biphasic effect: depending on their concentrations they increase or decrease enzyme activity. It may be due to two types of interactions: direct--between dendrimers and the enzyme; indire... |
15507309 | Monoclonal antibody analysis of porcine reproductive and respiratory syndrome virus epitopes associated with antibody-dependent enhancement and neutralization of virus infection. | Enhanced infection and replication of porcine reproductive and respiratory syndrome (PRRS) virus in the presence of specific antibody has been demonstrated in vitro and in vivo, a phenomenon known as antibody-dependent enhancement (ADE). ADE is considered to be a significant obstacle to developing effective vaccines fo... |
15501572 | In vitro biochemical and thermodynamic characterization of nucleocapsid protein of SARS. | The major biochemical and thermodynamic features of nucelocapsid protein of SARS coronavirus (SARS_NP) were characterized by use of non-denatured gel electrophoresis, size-exclusion chromatographic and surface plasmon resonance (SPR) techniques. The results showed that SARS_NP existed in vitro as oligomer, more probabl... |
15501570 | Activation of ryanodine receptors in the nuclear envelope alters the conformation of the nuclear pore complex. | Nuclear pore complexes (NPCs) are supramolecular protein pores that traverse the nuclear envelope and form the only known direct route of transport between the cytoplasmic and nuclear spaces. Detailed studies have identified both active and passive mechanisms of transport through the NPC and structural studies have rev... |
15388119 | Molecular recognition and stability of 99mTc-UBI 29-41 based on experimental and semiempirical results. | 99mTc-UBI 29-41 is an antimicrobial peptide fragment that directly radiolabeled with 99mTc shows high in vitro and in vivo stability, rapid background clearance, minimal accumulation in non-target tissues and rapid detection of infection sites. Molecular mechanics (MM) calculation has been an essential tool in explaini... |
15172497 | Modification of fibrous poly(L-lactic acid) scaffolds with self-assembling triblock molecules. | Molecular self-assembly offers an effective method to modify the surface properties of common biomaterials by presenting biologically relevant chemistry in a controlled, ordered fashion. This work reports on self-assembling triblock molecules containing rigid cholesteryl segments followed by flexible oligomers of L-(la... |
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