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12935303 | A chromatographic approach to analyze dansyl amino acid-HP-beta-CD association using macrocyclic antibiotic as the stationary phase. | The retention mechanism for a series of D,L-dansyl amino acids in high-performance liquid chromatography is investigated using a teicoplanin stationary phase and hydroxypropyl-beta-cyclodextrin (HP-beta-CD) as the mobile phase additive (0-16mM). A theoretical treatment is developed to determine the HP-beta-CD influence... |
12934640 | Effect of active synthetic 2-substituted quinazolinones on anti-platelet aggregation and the inhibition of superoxide anion generation by neutrophils. | Quinazolinones, 2-substituted and 3-substituted, mainly synthesized by microwave irradiation, were subjected to anti-platelet aggregation and inhibition of superoxide anion generation assays. Interestingly, 2-phenyl-4-quinazolinone (4) exhibited significant inhibitory activities toward platelet aggregation and neutroph... |
12926044 | Matrix-dependent plasticity of the malignant phenotype of bladder cancer cells. | The purpose of this study was to investigate the effect of cancer- and normal basement membrane-derived extracellular matrix to modulate the phenotype of bladder cancer cell lines. Five lines, varying in malignancy from papilloma to highly undifferentiated and invasive and immortalized human urothelial cells, were grow... |
12924778 | Novel benzo-15-crown-5 sol-gel coating for solid-phase microextraction. | A novel dihydroxy-terminated benzo-15-crown-5 was synthesized and applied to prepare a solid-phase microextraction (SPME) fiber coating with sol-gel technology. The optimization of the sol-gel process was studied. The coating method with sol-gel was improved and completed in one run, which economized materials and allo... |
12924562 | Robustness testing of chiral separations by capillary electrophoresis using highly-sulfated cyclodextrins. | The robustness of a generic method for chiral separation in capillary electrophoresis using highly-sulfated cyclodextrins in a low pH phosphate buffer and the "short-end injection technique" was studied. In this study, we focused on the robustness of the separations and not of the quantitative analysis of the enantiome... |
12918818 | Postural and neurological deficits in broiler chicks after cervical vaccination with live vaccine. | A disease characterized by paresis and paralysis was seen in 7-9-day-old broiler chicks after vaccination in the neck area at day-of-age with a live virus vaccine containing viruses of Marek's disease, fowl pox, and infectious bursal disease. Affected birds presented with variable signs of ataxia, lateral recumbency, l... |
12909060 | Covalently attached sandwich structure from colloidal particles and diazoresin. | A covalently attached sandwich structure between layers and particles has been fabricated from z.sbnd;COOH-containing copolymer latex particles and z.sbnd;N(2)(+)-containing polymers by self-assembly combined with a UV irradiation technique. The ionic bonds involving the layers and particles change to covalent bonds un... |
12909044 | Adsorption and isotope effects by ion exchange with 1-aza-12-crown-4 bonded Merrifield peptide resin. | Magnesium isotope effects were investigated by chemical ion exchange with synthesized 1-aza-12-crown-4 bonded Merrifield peptide resin using elution chromatography. The capacity of azacrown ion exchanger was 0.89 meq/g dry resin. The heavier isotopes of magnesium were enriched in the resin phase, while the lighter isot... |
12909037 | Silica nanobottles templated from functional polymer spheres. | Nanosized hollow silica spheres with holes in the wall (denoted as silica nanobottles) have been successfully prepared by assembly of functional polymer nanospheres with tetraethoxysilane (TEOS) through hydrothermal methods, coupled with removal of the core by programmed calcination. The functional polymer nanospheres ... |
12898671 | Directional shape complementarity at the protein-DNA interface. | Nature utilizes various styles of architecture for DNA-binding proteins to recognize diverse DNA sequences, a process facilitated by a complementary surface between protein and DNA. However, the extent and ways this 'shape complementarity' occurs at the protein-DNA interface have yet to be characterized. Here, by analy... |
12898670 | Analysis of the pH-dependencies of the association and dissociation kinetics of HIV-1 protease inhibitors. | The kinetic constants for the interactions between HIV-1 protease and a selection of inhibitors were determined at different pH-values using a biosensor based interaction assay. Since this technique does not involve a substrate, it was possible to determine the pH-dependencies of the association and dissociation rates ... |
12898669 | Molecular electrostatic potential as a factor of drug-receptor recognition. | When a drug molecule approaches a non-specific acceptor both molecules are in electrostatic fields of equal sign which prevents drug-acceptor complex formation. At the same time, the drug-acceptor system does not achieve the thermodynamic global minimum. Otherwise, when a certain drug interacts with its specific recept... |
12898668 | Long-range and short-range mechanisms of hydrophobic attraction and hydrophilic repulsion in specific and aspecific interactions. | Among the three different non-covalent forces acting in aqueous media, i.e. Lifshitz-van der Waals (LW), Lewis acid-base (AB) and electrical double layer (EL) forces, the AB forces or electron-acceptor/electron-donor interactions are quantitatively by far the predominant ones. A subset of the AB forces acting in water ... |
12898667 | Solid supports for microarray immunoassays. | Stimulated by the achievements of the first phase in genomics and the resulting need of assigning functions to the acquired sequence information, novel formats of immunoassays are being developed for high-throughput multi-analyte studies. In principle, they are similar in nature to the microarray assays already establi... |
12898652 | Studies on the non-covalent complexes between oleanolic acid and cyclodextrins using electrospray ionization tandem mass spectrometry. | Non-covalent inclusion complexes formed between an anti-inflammatory drug, oleanolic acid (OA), and alpha-, beta- and gamma-cyclodextrins (CDs) were investigated by means of solubility studies and electrospray ionization tandem mass spectrometry (ESI-MS(n)). The order of calculated association constants (K(1 : 1)) of c... |
12895301 | Identification of essential histidines in cyclodextrin glycosyltransferase isoform 1 from Paenibacillus sp. A11. | The isoform 1 of cyclodextrin glycosyltransferase (CGTase, EC 2.4.1.19) from Paenibacillus sp. A11 was purified by a preparative gel electrophoresis. The importance of histidine, tryptophan, tyrosine, and carboxylic amino acids for isoform 1 activity is suggested by the modification of the isoform 1 with various group-... |
12893533 | Modulation of MRP1-like efflux activity in human erythrocytes caused by membrane perturbing agents. | The effect of membrane perturbing agents on the efflux (37 degrees C, 60 min) of the fluorescent probe 2', 7'-bis-(carboxypropyl)-5(6)-carboxyfluorescein (BCPCF) from human erythrocytes was studied. Several anionic amphiphiles (detergents) markedly inhibited BCPCF efflux (IC50 < or = 40 microM). Most zwitter-ionic amph... |
12889782 | Itraconazole formulation studies of the melt-extrusion process with mixture design. | Itraconazole is a poorly water soluble compound. One method to increase the aqueous solubility of itraconazole is through formation of a solid dispersion. The purpose of this study is to develop a 40% w/w itraconazole formulation through solid dispersion formation, using hydroxypropyl-beta-cyclodextrin (HP-beta-CD) and... |
12885409 | Characterization of rapid and high-affinity uptake of L-serine in neurons and astrocytes in primary culture. | The non-essential amino acid L-serine was shown to be required to support the survival of rat cerebellar Purkinje neurons because of lack of the expression of the L-serine biosynthesis enzyme 3-phosphoglycerate dehydrogenase in them. In the present study, we investigated L-[(3)H]serine uptake in primary cultures of neu... |
12885392 | Spray-dried redispersible oil-in-water emulsion to improve oral bioavailability of poorly soluble drugs. | A physically stabilized dry emulsion dosage form reforming the original emulsion after rehydration was developed by spray-drying a liquid oil-in-water emulsion containing maltodextrin as carrier and sodium caseinate as emulsifying agent. Several oil:water as well as maltodextrin:water ratios were tested, the homogeniza... |
12880700 | Dendrimer-mediated transdermal delivery: enhanced bioavailability of indomethacin. | The transdermal delivery of aqueous formulations of indomethacin, a model drug, with different concentrations of three types of dendrimer showed a linear increase in flux with increasing concentration of each of the dendrimers. This result was in contrast to phase solubility studies, where Higuchi's A(N) profile was ob... |
12880699 | Polymer vesicles in vivo: correlations with PEG molecular weight. | PEG-modified lipid vesicles have already shown considerable utility in delaying vesicle clearance from the circulation. They are, however, limited in their ability to stably integrate high molar ratios of PEG-lipid due to the high curvature and micellar preference of the very large hydrophilic PEG chain. Polymersomes, ... |
12879065 | Epitaxial self-assembly of block copolymers on lithographically defined nanopatterned substrates. | Parallel processes for patterning densely packed nanometre-scale structures are critical for many diverse areas of nanotechnology. Thin films of diblock copolymers can self-assemble into ordered periodic structures at the molecular scale (approximately 5 to 50 nm), and have been used as templates to fabricate quantum d... |
12877537 | Bis-functionalized fullerene-dibenzo[18]crown-6 conjugate: synthesis and cation-complexation dependent redox behavior. | A one-step synthesis of bis-pyrrolidine functionalized fullerene-dibenzo[18]crown-6 conjugate and its metal cation complexation to the crown ether entity dependent redox behavior is reported. |
12877527 | Synthesis of a novel crown ether derived from chiro-inositol and its catalytic activity on the asymmetric Michael addition. | A novel 18-membered chiral crown ether was prepared in four steps starting from L-quebrachitol, a chiro-inositol, and its catalytic activity in the Michael addition reaction of glycine imine with several Michael acceptors was studied. |
12877525 | Crystal structure of mono[3-(2-imidazolylthio)]-altro-beta-cyclodextrin: elliptical distortion of the cavity and unique 'Yin-Yang' stacking. | The title compound is elliptically distorted due to the unusual 1C4 geometry of the altrose portion. In packing, a unique fourfold helical structure is elaborated with head-to-head dimers as the repeating motif. The imidazolyl moieties mutually reside on each other's cavities thereby resembling the Yin-Yang type balanc... |
12877511 | Attachment of phosphonate-functionalised azo-dyes to oxide surfaces to give enhanced light and wet fastness. | Phosphonate-functionalised dyes have been shown to bind strongly to aluminium oxides and to form stable 1:1 complexes with cyclodextrins at the surface. |
12877477 | Donor-substituted peralkynylated "radiaannulenes": novel all-carbon macrocycles with an intense intramolecular charge-transfer. | A novel class of planar, highly conjugated all-carbon macrocycles, which we christened "radiaannulenes", have been prepared based on acetylenic scaffolding using tetraethynylethene (TEE) building blocks; these structures are powerful electron acceptors and, upon peripheral substitution with electron-donating N,N-dialky... |
12819774 | Ordered nanoporous polymer-carbon composites. | Nanostructured organic materials, particularly those constructed with uniform nanopores, have been sought for a long time in materials science. There have been many successful reports on the synthesis of nanostructured organic materials using the so-called, 'supramolecular liquid crystal templating' route. Ordered nano... |
12876278 | Regulation of phospholipase D1 subcellular cycling through coordination of multiple membrane association motifs. | The signaling enzyme phospholipase D1 (PLD1) facilitates membrane vesicle trafficking. Here, we explore how PLD1 subcellular localization is regulated via Phox homology (PX) and pleckstrin homology (PH) domains and a PI4,5P2-binding site critical for its activation. PLD1 localized to perinuclear endosomes and Golgi in ... |
12875408 | Effect of randomly methylated beta-cyclodextrin on physical properties of soils. | The application of cyclodextrins in several soil remediation technologies has been increasingly studied, but little is known about their effects on soil physical properties. One of the popular soil remediation additives, randomly methylated beta-cyclodextrin (RAMEB), was found to significantly alter surface and pore pr... |
12873145 | A novel, modification-dependent ATP-binding aptamer selected from an RNA library incorporating a cationic functionality. | An analogue of uridine triphosphate containing a cationic functional group was incorporated into a degenerate RNA library by enzymatic polymerization. In vitro selection experiments using this library yielded a novel receptor that binds ATP under physiological pH and salt conditions in a manner completely dependent on ... |
12873127 | Proteasome-cytochrome c interactions: a model system for investigation of proteasome host-guest interactions. | Owing to its high thermal stability and structural simplicity, the archaebacterium Thermoplasma Acidophilum 20S proteasome was selected for mechanistic studies in this work. This oligomeric enzyme complex consists of a barrel-shaped 20S core (approximately 700kDa) comprised of four stacked seven-membered rings with a a... |
12871288 | Molecular recognition in the protein C anticoagulant pathway. | The protein C (PC) anticoagulant system provides specific and efficient control of blood coagulation. The system comprises circulating or membrane-bound protein components that take part in complicated multimolecular protein complexes being assembled on specific cellular phospholipid membranes. Each of the participatin... |
12870963 | Structural, magnetic, and optoelectronic properties of (diimine)(dithiolato)platinum(II) and -palladium(II) complexes and their charge-transfer adducts with nitrile acceptors. | Two new diimine dithiolato complexes, (dbbpy)Pt(dmid), 1, and (dbbpy)Pd(dmid), 2, were prepared and characterized (dbbpy = 4,4'-di-tert-butyl-2,2'-bipyridine; dmid = 2-oxo-1,3-dithiole-4,5-dithiolate). Both complexes interact with the nitrile acceptor TCNQ, and 1 also interacts with TCNQF(4) and TCNE (TCNQ = 7,7,8,8-te... |
12870942 | Pulsed EPR and NMR spectroscopy of paramagnetic iron porphyrinates and related iron macrocycles: how to understand patterns of spin delocalization and recognize macrocycle radicals. | Pulsed EPR spectroscopic techniques, including ESEEM (electron spin echo envelope modulation) and pulsed ENDOR (electron-nuclear double resonance), are extremely useful for determining the magnitudes of the hyperfine couplings of macrocycle and axial ligand nuclei to the unpaired electron(s) on the metal as a function ... |
12871910 | Functional redundancy within roX1, a noncoding RNA involved in dosage compensation in Drosophila melanogaster. | Drosophila melanogaster males dosage compensate by twofold upregulation of the expression of genes on their single X chromosome. This process requires at least five proteins and two noncoding RNAs, roX1 and roX2, which paint the male X chromosome. We used a deletion analysis to search for functional RNA domains within ... |
12869322 | Nanoscale solid-state quantum computing. | Most experts agree that it is too early to say how quantum computers will eventually be built, and several nanoscale solid-state schemes are being implemented in a range of materials. Nanofabricated quantum dots can be made in designer configurations, with established technology for controlling interactions and for rea... |
12868880 | Polymer-supported bisBINOL ligands for the immobilization of multicomponent asymmetric catalysts. | [reaction: see text] Polymer-supported bisBINOL ligands were successfully utilized for the immobilization of multicomponent asymmetric catalysts. The polymer-supported Al-Li-bis(binaphthoxide) (ALB) catalyst was more effective than the dendrimer-supported ALB in the Michael reaction of 2-cyclohexen-1-one with dibenzyl ... |
12868866 | Angular ligand constraint yields an improved olefin aziridination catalyst. | [reaction: see text] The use of a pyridinophane, a macrocycle composed of three pyridines linked, via all ortho positions through CH(2) or CH(2)CH(2) groups, bound to copper, gives good performance (rate and yield) catalyzing the conversion of substituted aliphatic olefins and PhINTs to aziridines. Advantages also deri... |
12868946 | "Lego" chemistry for the straightforward synthesis of dendrimers. | A new straightforward method of synthesis of dendrimers, using two branched monomers (CA(2) and DB(2)), is described. Each generation is obtained in a single quantitative step, with only N(2) or H(2)O as byproducts; generation 4 is obtained in only four steps. The end groups are alternatively phosphines and hydrazines;... |
12868933 | Palladium-catalyzed benzannulation from alkynes and allylic compounds. | Various alkynes reacted with allyl tosylates in the presence of palladium catalysts, giving polysubstituted benzenes with good to high regioselectivity. Pentasubstituted and trisubstituted benzenes were readily prepared by reaction of internal alkynes and terminal alkynes, respectively. The combination of allyl alcohol... |
12868912 | Synthesis and structure of macrocyclic bis(hydroxynaphthoic amide)s connected by an achiral or chiral diamine. | Macrocyclic bis(hydroxynaphthoic amide)s 6, connected by an achiral or chiral diamine, were synthesized by the tandem Claisen rearrangement. CD spectra, X-ray crystallographic analyses, and variable-temperature NMR measurements of the chiral bis(hydroxynaphthoic amide)s revealed that the two hydroxynaphthalene rings in... |
12868726 | Induction of optical activity in oligosilanes within the internal cavity of cyclodextrins. | The first example of induced optical activity of oligosilanes within the internal cavity of gamma-cyclodextrins is reported. |
12868717 | Construction of the first cross-linked double helical polyiodide. | A homobimetallic supramolecular helicate has been used to template the formation of a polyiodide network which adopts an infinite cross-linked double helical structure, topologically analogous to DNA. |
12840783 | New molecular mechanism for Ullrich congenital muscular dystrophy: a heterozygous in-frame deletion in the COL6A1 gene causes a severe phenotype. | Recessive mutations in two of the three collagen VI genes, COL6A2 and COL6A3, have recently been shown to cause Ullrich congenital muscular dystrophy (UCMD), a frequently severe disorder characterized by congenital muscle weakness with joint contractures and coexisting distal joint hyperlaxity. Dominant mutations in al... |
12862487 | Orientation modulation of a synthetic polypeptide in self-assembled monolayers: a TOF-SIMS study. | Structure and orientation of molecules are key properties of functionalized surfaces. Using time-of-flight secondary ion mass spectrometry (TOF-SIMS), here we investigate how to modulate these parameters upon the immobilization process varying the conditions of self-assembly. The molecule of interest, a template-assemb... |
12862482 | Control of redox transitions and oxygen species binding in Mn centers by biologically significant ligands; model studies with [Mn]-bacteriochlorophyll a. | Mn-superoxide dismutase (Mn-SOD), which protects the cell from the toxic potential of superoxide radicals (O(2)(-*)), is the only type of SOD which resides in eukaryotic mitochondria. Up-to-date, the exact catalytic mechanism of the enzyme and the relationship between substrate moieties and the ligands within the activ... |
12862477 | Altering the strength of lectin binding interactions and controlling the amount of lectin clustering using mannose/hydroxyl-functionalized dendrimers. | Protein-carbohydrate interactions play a critical role in many biological recognition events. Multivalent therapeutic agents that utilize protein-carbohydrate interactions have proven difficult to design, primarily because the fundamental requirements of protein-carbohydrate interactions are not well understood. Here, ... |
12866081 | New molecular topologies by fourfold metathesis reactions within a hydrogen-bonded calix[4]arene dimer. | A calix[4]arene tetrapentyl ether in the cone conformation substituted at its wide rim by four m-(omega-octenyloxy)phenyl urea groups forms hydrogen-bonded dimeric capsules in dichloromethane/benzene (95:5). Metathesis reaction with Grubbs' catalyst under high-dilution conditions (1.1 x 10(-4) M) followed by hydrogenat... |
12866063 | Coordinated and clathrated guests in the 3infinity[Hg6As4]4+ bicompartmental framework: synthesis, crystal and electronic structure, and properties of the novel supramolecular complexes [Hg6As4](CrBr6)Br and [Hg6As4](FeBr6)Hg0.6. | Two new supramolecular complexes [Hg(6)As(4)](CrBr(6))Br (1) and [Hg(6)As(4)](FeBr(6))Hg(0.6) (2) have been prepared by the standard ampoule technique and their crystal structures determined. Both crystallize in the cubic space group Pa$\bar 3$ with the unit cell parameter a=12.275(1) (1) and 12.332(1) A (2), and Z=4. ... |
12865936 | Enhanced effects of aminolaevulinic acid-based photodynamic therapy through local hyperthermia in rat tumours. | The possibility of enhancing aminolaevulinic acid (ALA)-based photodynamic therapy (PDT) by simultaneous application of localised hyperthermia (HT) was evaluated. Treatments of rat DS-sarcomas included: (i) control, (ii) ALA administration (375 mg kg(-1), i.p.), no illumination, (iii) 'nonthermal' illumination, (iv) AL... |
12862427 | Enzymatic modification of self-assembled peptide structures with tissue transglutaminase. | A de novo peptide that self-assembles into fibrillar structures and serves as a substrate for the cross-linking enzyme tissue transglutaminase was developed (Ac-QQKFQFQFEQQ-Am). Congo red staining, circular dichroism, and FTIR spectroscopy showed that this 11-amino acid peptide produced predominantly beta-sheet structu... |
12860131 | Structural analysis of the epitope of the anti-HIV antibody 2F5 sheds light into its mechanism of neutralization and HIV fusion. | Inhibition of human immunodeficiency virus (HIV) fusion with the host cell has emerged as a viable therapeutic strategy, and rational design of inhibitors and vaccines, interfering with this process, is a prime target for antiviral research. To advance our knowledge of the structural biology of HIV fusion, we have stud... |
12860034 | Simultaneous enantioselective analysis of chiral urinary metabolites in patients with Zellweger syndrome. | Enantio-MDGC-MS analysis with heptakis-(2,3-di-O-methyl-6-O-tert.-butyl-dimethylsilyl)-beta-cyclodextrin as the chiral main column is a powerful tool for the separation of chiral compounds. This paper reports on the simultaneous stereodifferentiation of 2-hydroxyisocaproic acid (HICA), 3-methyladipic acid (3-MA), 2-hyd... |
12860429 | A new crystal form of beta-cyclodextrin-ethanol inclusion complex: channel-type structure without long guest molecules. | A new crystal form of beta-cyclodextrin (beta-CD)[bond]ethanol[bond]dodecahydrate inclusion complex [(C(6)H(10)O(5))(7).0.3C(2)H(5)OH.12H(2)O] belongs to monoclinic space group C2 (form II) with unit cell constants a=19.292(1), b=24.691(1), c=15.884(1) A, beta=109.35(1) degrees. The beta-CD macrocycle is more circular ... |
12860426 | Mutual conversion of substrate specificities of Thermoactinomyces vulgaris R-47 alpha-amylases TVAI and TVAII by site-directed mutagenesis. | Thermoactinomyces vulgaris R-47 produces two alpha-amylases, TVAI and TVAII, differing in substrate specificity from each other. TVAI favors high-molecular-weight substrates like starch, and scarcely hydrolyzes cyclomaltooligosaccharides (cyclodextrins) with a small cavity. TVAII favors low-molecular-weight substrates ... |
12857774 | Receptors, mediators, and mechanisms involved in bacterial sepsis and septic shock. | Bacterial sepsis and septic shock result from the overproduction of inflammatory mediators as a consequence of the interaction of the immune system with bacteria and bacterial wall constituents in the body. Bacterial cell wall constituents such as lipopolysaccharide, peptidoglycans, and lipoteichoic acid are particular... |
12857093 | Structural characterization of a lipase-catalyzed copolymerization of epsilon-caprolactone and D,L-lactide. | The copolymerization of epsilon-caprolactone (epsilon-CL) and d,l-lactide catalyzed by Candida antarctica lipase B was studied. Copolymerizations with different epsilon-CL-to-lactide ratios were carried out, and the product was monitored and characterized by MALDI-TOF MS, GPC, and (1)H NMR. The polymerization of epsilo... |
12857089 | Light scattering studies of the solution properties of chitosans of varying degrees of acetylation. | The use of two techniques, differential interferometry and quasi-elastic light scattering (QELS), allowed us to study solutions of chitosan varying in degree of acetylation (DA), degree of dissociation (alpha), and concentration (C(p)). With the first technique, we demonstrated the modification of the electric polariza... |
12857077 | Inclusion complex of beta-chitin and aliphatic amines. | Inclusion complexation of beta-chitin with linear aliphatic amines was studied by X-ray diffraction. All tested amines, C3 to C8 monoamines and C2 to C7 diamines with terminal amino groups, reversibly formed crystalline complexes with beta-chitin by immersion of dry chitin in pure liquid. Complex formation caused linea... |
12857065 | Nanoscale structure of poly(ethylene glycol) hybrid block copolymers containing amphiphilic beta-strand peptide sequences. | This paper discusses the solid state and melt nanoscale structure of a series of novel poly(ethylene glycol) (PEG) hybrid di- and triblock copolymers, which contain amphiphilic beta-strand peptide sequences. The block copolymers have been prepared via solid-phase synthesis, affording perfectly monodisperse peptide segm... |
12854157 | Construction of hpaA gene from a clinical isolate of Helicobacter pylori and identification of fusion protein. | <h4>Aim</h4>To clone hpaA gene from a clinical strain of Helicobacter pylori and to construct the expression vector of the gene and to identify immunity of the fusion protein.<h4>Methods</h4>The hpaA gene from a clinical isolate Y06 of H.pylori was amplified by high fidelity PCR. The nucleotide sequence of the target D... |
12853631 | Unusual intercalation of acridin-9-ylthiourea into the 5'-GA/TC DNA base step from the minor groove: implications for the covalent DNA adduct profile of a novel platinum-intercalator conjugate. | The binding of the novel cytotoxic acridine derivative, 1-[2-(acridin-9-ylamino)ethyl]-1,3-dimethylthiourea (ACRAMTU) to various self-complementary oligonucleotide duplexes has been studied by combined high-resolution NMR spectroscopy/restrained molecular dynamics and equilibrium binding assays to establish the sequenc... |
12853616 | Direct real-time molecular scale visualisation of the degradation of condensed DNA complexes exposed to DNase I. | The need to protect DNA from in vivo degradation is one of the basic tenets of therapeutic gene delivery and a standard test for any proposed delivery vector. The currently employed in vitro tests, however, presently provide no direct link between the molecular structure of the vector complexes and their success in thi... |
12853952 | Unidirectional rotation in a mechanically interlocked molecular rotor. | Molecular motor proteins are ubiquitous in nature and have inspired attempts to create artificial machines that mimic their ability to produce controlled motion on the molecular level. A recent example of an artificial molecular rotor is a molecule undergoing a unidirectional 120 degrees intramolecular rotation around ... |
12852759 | A conformationally locked analogue of the anti-HIV agent stavudine. An important correlation between pseudorotation and maximum amplitude. | The synthesis and biological evaluation of a bicyclo[3.1.0]hexene nucleoside designed as a conformational mimic of the anti-HIV agent stavudine (1, D4T) is described. The unsaturated methanocarbocyclic pseudosugar of N-MCD4T (2) was constructed from an iodo-substituted precursor by a DBU-catalyzed olefination reaction.... |
12853487 | A unique right end-enhancer complex precedes synapsis of Mu ends: the enhancer is sequestered within the transpososome throughout transposition. | Assembly of the Mu transpososome is dependent on interactions of transposase subunits with the left (L) and right (R) ends of Mu and an enhancer (E). We have followed the order and dynamics of association of these sites within a series of transpososomes prior to and during formation of a three-site complex (LER), engag... |
12853463 | Structure, function and evolution of the signal recognition particle. | The signal recognition particle (SRP) is a ribonucleoprotein particle essential for the targeting of signal peptide-bearing proteins to the prokaryotic plasma membrane or the eukaryotic endoplasmic reticulum membrane for secretion or membrane insertion. SRP binds to the signal peptide emerging from the exit site of the... |
12852850 | Fertility and taxon-specific sperm binding persist after replacement of mouse sperm receptors with human homologs. | The zona pellucida surrounding ovulated mouse eggs contains three glycoproteins, two of which (ZP2 and ZP3) are reported sperm receptors. After fertilization, the zona pellucida is modified ad minimus by cleavage of ZP2, and sperm no longer bind. Crosstaxa sperm binding is limited among mammals, and human sperm do not ... |
12853390 | Recombinant single-chain variable fragment antibodies directed against Clostridium difficile toxin B produced by use of an optimized phage display system. | Recombinant antibody cloning and phage display technologies were used to produce single-chain antibodies (scFv) against Clostridium difficile toxin B. The starting material was the mouse B cell hybridoma line 5A8, which generates a monoclonal antibody against the toxin. The integrated cloning, screening, and phage disp... |
12850432 | Structure-stability-function relationships of dendritic spines. | Dendritic spines, which receive most of the excitatory synaptic input in the cerebral cortex, are heterogeneous with regard to their structure, stability and function. Spines with large heads are stable, express large numbers of AMPA-type glutamate receptors, and contribute to strong synaptic connections. By contrast, ... |
12848572 | Electrochemically switchable hydrogen-bonded molecular shuttles. | A series of [2]rotaxanes containing succinamide and naphthalimide hydrogen-bonding stations for a benzylic amide macrocycle is described. Electrochemical reduction and oxidation of the naphthalimide group alters its ability to form hydrogen bonds to the macrocycle to such a degree that redox processes can be used to sw... |
12848568 | Ligand-directed molecular architectures: self-assembly of two-dimensional rectangular metallacycles and three-dimensional trigonal or tetragonal prisms. | Three angular ditopic ligands (1,3-bis(benzimidazol-1-ylmethyl)-4,6-dimethylbenzene L(1), 1,3-bis(benzimidazol-1-ylmethyl)-2,4,6-trimethylbenzene L(2), and 1,4-bis(benzimidazol-1-ylmethyl)-2,3,5,6-tetramethylbenzene L(3)) and one tripodal ligand 1,3,5-tris(benzimidazol-1-ylmethyl)-2,4,6-trimethylbenzene L(4) have been ... |
12848565 | Functionalization of single-walled carbon nanotubes with (R-)oxycarbonyl nitrenes. | Sidewall functionalization of single-walled carbon nanotubes (SWCNTs) via the addition of (R-)oxycarbonyl nitrenes allows for the covalent binding of a variety of different groups such as alkyl chains, aromatic groups, dendrimers, crown ethers, and oligoethylene glycol units. Such additions lead to a considerable incre... |
12848552 | Remarkably size-regulated cell invasion by artificial viruses. Saccharide-dependent self-aggregation of glycoviruses and its consequences in glycoviral gene delivery. | We here report a novel example of artificial glycoviral vectors constructed via number- and size-controlled gene (pCMVluc, 7040 bp) coating with micellar glycocluster nanoparticles (GNPs) of calix[4]resorcarene-based macrocyclic glycocluster amphiphiles having eight or five saccharide moieties with terminal alpha-gluco... |
12848509 | Stereoselectivity of the generation of 3-mercaptohexanal and 3-mercaptohexanol by lipase-catalyzed hydrolysis of 3-acetylthioesters. | The enantioselectivity of the generation of 3-mercaptohexanal and 3-mercaptohexanol, two potent sulfur-containing aroma compounds, by lipase-catalyzed hydrolysis of the corresponding 3-acetylthioesters was investigated. The stereochemical course of the kinetic resolutions was followed by capillary gas chromatography us... |
12846565 | The small protein CP12: a protein linker for supramolecular complex assembly. | CP12 is an 8.5-kDa nuclear-encoded chloroplast protein, isolated from higher plants. It forms part of a core complex of two dimers of phosphoribulokinase (PRK), two tetramers of glyceraldehyde 3-phosphate dehydrogenase (GAPDH), and CP12. The role of CP12 in this complex assembly has not been determined. To address this... |
12844307 | Synthesis, complexation, and coordination oligomerization of 1,8-pyrazine-capped 5,12-dioxocyclams. | (Methyl)(methoxy)-5,12-dioxocyclam 1 was alkylated on the secondary amines (capped) with 2,6-bis(bromomethyl)pyrazine. The resulting macrocycle was complexed to copper(II) to produce a five-coordinate complex 5a which was fully characterized by a range of spectroscopic methods (IR, UV-vis, ESR) as well as by X-ray crys... |
12844296 | Organic-organometallic crystal engineering: novel formation of a honeycomb supramolecular architecture of [Re2(mu-OMe)3(CO)6]- anions encapsulating a linear H-bonded chain of [DABCO-H]+ cations. | The title salt [Re(2)(mu-OMe)(3)(CO)(6)](-)[DABCO-H](+) (1) was prepared as colorless prismatic crystals by the reaction of DABCO with Re(CO)(5)(OTf) in refluxing methanol solution and was characterized by spectroscopic means including single-crystal X-ray diffraction techniques. The molecular structure of 1 revealed t... |
12842041 | Malignant brain tumor repeats: a three-leaved propeller architecture with ligand/peptide binding pockets. | We report on the X-ray structure of three 100-amino acid mbt repeats in h-l(3)mbt, a polycomb group protein involved in transcriptional repression, whose gene is located in a region of chromosome 20 associated with hematopoietic malignancies. Interdigitation between the extended arms and cores of the mbt repeats result... |
12842147 | Two very unusual macrocyclic flavonoids from the water lily Nymphaea lotus. | Three novel flavonols, myricetin-3'-O-(6"-p-coumaroyl)glucoside and two epimeric macrocyclic derivatives, as well as the known myricetin-3-O-rhamnoside and pentagalloyl glucose, have been isolated from the wild water lily Nymphaea lotus L. and identified using 2D NMR. This is the first report of such a macrocycle from ... |
12841777 | Synthesis of novel phenylazomethine dendrimers having a cyclam core and their zinc complex. | [structure: see text] Novel phenylazomethine dendrimers having a cyclam core were synthesized by the convergent method. The dendrimers showed selective coordination with zinc chloride on the cyclam ring and with tin chloride on the imine groups. The metal cyclam exhibits a metal-assembling function to provide a multinu... |
12841769 | Automatic chiral selection in a thermodynamically predisposed metathesis reaction. | [reaction: see text] Tryptophan-derived azoninoindole imines select partners of the same chirality for dimerization to helical macrocycles. |
12841747 | Stereoselective synthesis of 4-hydroxy-2,3,6-trisubstituted tetrahydropyrans. | [reaction: see text] Reaction of homoallylic alcohols with aldehydes in the presence of TFA gives, after hydrolysis of the ester, 4-hydroxy-2,3,6-trisubstituted tetrahydropyrans with the creation of three new stereocenters in a single-pot process. By varying the aldehyde component, a variety of functionalized side chai... |
12841737 | Diverse motifs of mannoside clustering on a beta-cyclodextrin core. | [reaction: see text] A new method for the synthesis of beta-cyclodextrin-based cluster mannosides by application of the Sonogashira cross-coupling reaction is described. The method allows for the persubstitution of the beta-cyclodextrin at either 2- and 3-positions to give two types of heptavalent clusters, at both 2- ... |
12843298 | Long-term depression of presynaptic release from the readily releasable vesicle pool induced by NMDA receptor-dependent retrograde nitric oxide. | Postsynaptic alterations are currently believed to be able to fully account for NMDA-receptor-dependent long-term depression (LTD) and long-term potentiation of synaptic strength, although there is also evidence supporting changes in presynaptic release. Using dualphoton laser scan microscopy of N-(3-triethylammoniumpr... |
12843245 | Antibody cross-linking of myelin oligodendrocyte glycoprotein leads to its rapid repartitioning into detergent-insoluble fractions, and altered protein phosphorylation and cell morphology. | Myelin oligodendrocyte glycoprotein (MOG) is, quantitatively, a relatively minor component of the myelin membrane. Nevertheless, peritoneal administration of MOG evokes potent cellular and humoral immunoreactivity, resulting in an experimental allergic encephalitis with immunopathology similar to multiple sclerosis. Mo... |
12842348 | Ternary systems of naproxen with hydroxypropyl-beta-cyclodextrin and aminoacids. | The purpose of the present study was to investigate the combined effect of hydroxypropyl-beta-cyclodextrin and different aminoacids (L-lysine, LYS; L-valine, VAL; L-iso-leucine, LEU; and L-arginine, ARG) on the solubility of naproxen, a poorly water-soluble anti-inflammatory drug. Aqueous solubilities of naproxen in bi... |
12843598 | An antitumor agent of beta-cyclodextrin-modified titanocene complex: synthesis and characterization. | The complex of a derivative of beta-cyclodextrin, that is mono[6-deoxy-6-(2-butenedinitrile-2,3-dimercapto sodium salt)]-beta-cyclodextrin (6-mnt-beta-CD), with titanocene (titanocene di[mono[6-deoxy-6-(2-butenedinitrile-2,3-dimercapto)]-beta-cyclodextrin], Cp2Ti[6-mnt-beta-CD]2) has been synthesized and characterized ... |
12693993 | Induction of glycosylation in human C-reactive protein under different pathological conditions. | As an acute-phase protein, human C-reactive protein (CRP) is clinically important. CRPs were purified from several samples in six different pathological conditions, where their levels ranged from 22 to 342 microg/ml. Small, but significant, variations in electrophoretic mobilities on native PAGE suggested differences i... |
12839989 | Structural basis of the interaction between RalA and Sec5, a subunit of the sec6/8 complex. | The sec6/8 complex or exocyst is an octameric protein complex that functions during cell polarization by regulating the site of exocytic vesicle docking to the plasma membrane, in concert with small GTP-binding proteins. The Sec5 subunit of the mammalian sec6/8 complex binds Ral in a GTP-dependent manner. Here we repor... |
12839987 | Annexin II regulates multivesicular endosome biogenesis in the degradation pathway of animal cells. | Proteins of the annexin family are believed to be involved in membrane-related processes, but their precise functions remain unclear. Here, we have made use of several experimental approaches, including pathological conditions, RNA interference and in vitro transport assays, to study the function of annexin II in the e... |
12839783 | Contributions of atmospheric CO and hydrogen uptake to microbial dynamics on recent Hawaiian volcanic deposits. | A series of sites were established on Hawaiian volcanic deposits ranging from about 18 to 300 years old. Three sites occurred in areas that supported tropical rain forests; the remaining sites were in areas that supported little or no plant growth. Sites >26 years old consumed atmospheric CO and hydrogen at rates rangi... |
12837101 | Host-[2]rotaxanes as cellular transport agents. | Host-[2]rotaxanes, containing a diarginine-derivatized dibenzo-24-crown-8 (DB24C8) ether as the ring and a cyclophane pocket or an aromatic cleft as one blocking group, are cell transport agents. These hosts strongly associate with a variety of amino acids, dipeptides, and fluorophores in water (1 mM phosphate buffer, ... |
12837099 | Guanidinium receptors as enantioselective amino acid membrane carriers. | A number of artificial carriers for the transport of zwitterionic aromatic amino acids across bulk model membranes (U-tube type) have been prepared and evaluated. 1,2-Dichloroethane and dichloromethane were employed in the organic phase. All compounds are based on a bicyclic chiral guanidinium scaffold that ideally com... |
12837096 | Structural effects on encapsulation as probed in redox-active core dendrimer isomers. | Three pairs of isomeric, iron-sulfur core dendrimers were prepared. Each isomer pair was distinguished by a 3,5-aromatic substitution pattern (extended) versus 2,6-aromatic substitution pattern (backfolded). Several observations were made that supported the hypothesis that the iron-sulfur cluster cores were encapsulate... |
12837079 | Rapid synthesis of polyamide dendrimers from unprotected AB2 building blocks. | A rapid synthetic method for the preparation of polyamide dendrimer without protection and deprotection steps has been developed. A symmetrically branched third-generation polyamide dendrimer was prepared by a convergent method involving activation of focal point with a condensing agent, diphenyl (2,3-dihydro-2-thioxo-... |
12837071 | Novel triarylamine dendrimers as a hole-transport material with a controlled metal-assembling function. | A series of phenylazomethine dendrimers with a triarylamine core (TPA-DPA) were synthesized by dehydration using TiCl4. The complexation of the fourth genereration (G4) TPA-DPA with SnCl2 proceeds in not a random but a stepwise fashion from the core to the terminal imines of the G4 dendrimer. The molecular size of TPA-... |
12837065 | The pentapeptide GGAGG has PII conformation. | Most of what we know about proteins reflects their native folded structure. Much less is understood about the structure of unfolded proteins, which tends to be referred to as "random coil", lacking extended alpha-helix or beta-strand structure. Recent work suggests that unfolded proteins might adopt significant populat... |
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