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9764486 | Nonaqueous capillary electrophoresis chiral separations with quaternary ammonium beta-cyclodextrin. | Chiral separation of nonsteroidal anti-inflammatory drugs (profens), 1,1'-binaphthyl-2,2'-diyl-hydrogen phosphate, N-[1-(1-naphthyl)ethyl]phthalamic acid, and derivatized amino acids by a cationic cyclodextrin, quaternary ammonium beta-cyclodextrin (QA-beta-CD), was investigated by capillary electrophoresis (CE) in bot... |
9760990 | The angiogenins. | The angiogenic and other biological functions of the angiogenins, members of the pancreatic RNase superfamily of proteins, are reviewed in the context of their primary and tertiary structures. The ribonucleolytic activity and interactions with the placental ribonuclease inhibitor have seen much study in the last few ye... |
9760989 | Ribonuclease 4, an evolutionarily highly conserved member of the superfamily. | The structural and enzymatic properties of RNase 4 are reviewed. This RNase shows a much higher interspecies similarity (approximately 90%) than the other members of the RNase A superfamily. The enzyme is ubiquitous, with the highest amounts present in liver and lung. Its unique uridine specificity results from alterat... |
9751418 | The in vivo behavior of copper-64-labeled azamacrocyclic complexes. | The use of copper radioisotopes in imaging and therapy applications has created a greater need for bifunctional chelates (BFCs) for complexing copper radioisotopes to biomolecules. It has been demonstrated that the charge and lipophilicity of the Cu-BFC complex has a significant effect on the in vivo behavior of the ra... |
9750012 | Protective effects of a PAF receptor antagonist and a neutrophil elastase inhibitor on multiple organ failure induced by cerulein plus lipopolysaccharide in rats. | The inhibitory effects of YM264, a selective platelet activating factor (PAF) receptor antagonist, and 2-(3-methylsulfonylamino-2-oxo-6-phenyl-1,2-dihydro-1-pyridyl)-N-( 3,3,3-trifluoro-1-isopropyl-2-oxopropyl)acetamide (compound 1), a neutrophil elastase inhibitor, on mortality, and pancreatic, hepatic, renal and pulm... |
9746262 | Stereoselective determination of clenbuterol in human urine by capillary electrophoresis. | The effectiveness of capillary electrophoresis (CE) in the field of stereoselective determination of drugs in biological matrices is demonstrated by analyzing clenbuterol in human urine. Due to the very low therapeutical doses of 20-40 microg per day the total concentrations in urine are 1-10 ng/ml. The sample was extr... |
9746240 | Novel electrolyte for the analysis of cations in low explosive residue by capillary electrophoresis. | A novel electrolyte has been developed for the effective separation by capillary electrophoresis of cations detected in low explosive residue. This electrolyte, with a pH of 4.4, employs 17.5 mM alpha-hydroxyisobutyric acid (HIBA) as the complexing agent, 6 mM imidazole as the ultraviolet visualization agent, 4 mM 18-c... |
9746236 | Determination of chiral pharmaceutical compounds, terbutaline, ketamine and propranolol, by on-line capillary electrophoresis-electrospray ionization mass spectrometry. | On-line capillary electrophoresis-electrospray ionization mass spectrometry (CE-ESI-MS) has been employed for the determination of racemic mixtures of the chiral drugs, terbutaline, ketamine, and propranolol. Separation of the different chiral forms has been achieved by introducing cyclodextrins (CDs), which act as chi... |
9739086 | A domain flip as a result of a single amino-acid substitution. | <h4>Background</h4>The self-assembly properties of beta domains are important features of diverse classes of proteins that include cell-adhesion molecules, surface receptors and the immunoglobulin superfamily. Immunoglobulin light-chain variable domains are well suited to the study of structural factors that determine ... |
9742560 | Complexation and solubility behavior of albendazole with some cyclodextrins. | The main purpose of this work was to study the albendazole-cyclodextrins complexation equilibrium and to propose a suitable excipient to improve the solubility behavior and dissolution rate of albendazole. The complexation of albendazole with four cyclodextrins, alpha-CD, beta-CD, gamma-CD, and hydroxypropylated (HP)-b... |
9742551 | Binding, molecular mechanics, and thermodynamics of cyclodextrin inclusion complexes with ketoprofen in aqueous medium. | The purpose of this work was to study the interaction forces involved in the inclusion processes of ketoprofen with several cyclodextrins and to assess the best cyclodextrin for complexing this anti-inflammatory drug. The behavior of the inclusion complexes of ketoprofen with alpha-, beta-, and gamma-cyclodextrins was ... |
9742549 | Transdermal permeation modulation by cyclodextrins: a mechanistic study. | The purpose of this study was to investigate permeation modulation by beta- and 2-hydroxypropyl-beta-cyclodextrins (beta-CD and HP-beta-CD, respectively) alone and complexed with penetration enhancers for the test drugs 5-fluorouracil and estradiol through human skin, and to probe the value of the CDs in a barrier crea... |
9735227 | Expression of testosterone conditioned place preference is blocked by peripheral or intra-accumbens injection of alpha-flupenthixol. | Previous evidence indicates that peripheral and intranucleus accumbens injections of testosterone have rewarding effects in male rats as measured in a conditioned place preference (CPP) paradigm. The present study investigated the neurochemical bases of the rewarding properties of testosterone by examining the effect o... |
9741064 | Cyclodextrins in acetazolamide eye drop formulations. | The interaction of acetazolamide with beta-cyclodextrin, (beta-CD), dimethyl-beta-cyclodextrin (DM-beta-CD) and trimethyl-beta-cyclodextrin (TM-beta-CD) was monitored spectrophotometrically. The results revealed formation of equimolar complexes. The apparent solubility of acetazolamide in water was found to increase li... |
9733989 | Intrinsic protein electric fields: basic non-covalent interactions and relationship to protein-induced Stark effects. | Knowledge of the interactions involving charged, polar and polarizable groups in proteins is fundamental, not only because they are important determinants for gaining insight into biophysical molecular recognition and assembly processes, but also for understanding how the matrix of a protein can be viewed as an electri... |
9738922 | Photoaffinity labeling as an approach to study supramolecular nucleoprotein complexes. | The modern approaches for studying the detailed structure of nucleoprotein complexes involved in replication and transcription, based on the use of nucleic acids with photoreactive groups incorporated into definite positions of polynucleotide chain, are considered. Methods of preparation of photoreactive nucleic acids ... |
9738921 | HIV: from molecular recognition to tissue pathogenesis. | Dramatic progress has been made recently in identifying both viral and cellular molecules responsible for binding and fusion of HIV-1 to target cells. In vivo, HIV-1 infection is transmitted by viruses that recognize chemokine receptor CCR5, while viruses isolated at later stages of HIV disease often recognize another ... |
9738912 | Substrate binding to a cyclodextrin glycosyltransferase and mutations increasing the gamma-cyclodextrin production. | Bacterial cyclodextrin glycosyltransferases use starch to produce cyclic maltooligosaccharides (cyclodextrins) which are of interest in various applications. The cyclization reaction gives rise to a spectrum of ring sizes consisting of predominantly six to eight glucosyl units. Using the enzyme from Bacillus circulans ... |
9738464 | Mutational analysis of caveolin-induced vesicle formation. Expression of caveolin-1 recruits caveolin-2 to caveolae membranes. | Caveolae are vesicular organelles with a characteristic uniform diameter in the range of 50-100 nm. Although recombinant expression of caveolin-1 is sufficient to drive caveolae formation, it remains unknown what controls the uniform diameter of these organelles. One hypothesis is that specific caveolin-caveolin intera... |
9733935 | Surface plasmon resonance analysis at a supported lipid monolayer. | Methods for the formation of supported lipid monolayers on top of a hydrophobic self assembled monolayer in a surface plasmon resonance instrument are described. Small unilamellar vesicles absorb spontaneously to the surface of the hydrophobic self-assembled monolayer to form a surface which resembles the surface of a ... |
9731219 | Cholesterol oxides induce programmed cell death in microglial cells. | N9 microglial cells were used as a model to examine the effect of cholesterol oxides on central nervous system microglia. Results indicated that 25-OH-cholesterol was the most cytotoxic agent among the cholesterol oxides tested. During the process of cell death, this agent caused prominent nuclei condensation and signi... |
9727198 | PNA molecular beacons for rapid detection of PCR amplicons. | The authors have developed a method for rapid detection of polymerase chain reaction (PCR) amplicons based on surface immobilized PNA-DNA hybrid probes ('molecular beacons') that undergo a fluorescent-linked conformational change in the presence of a complementary DNA target. Amplicons can be detected by simply adding ... |
9722604 | Microinjection of anti-coilin antibodies affects the structure of coiled bodies. | The coiled body is a distinct subnuclear domain enriched in small nuclear ribonucleoprotein particles (snRNPs) involved in processing of pre-mRNA. Although the function of the coiled body is still unknown, current models propose that it may have a role in snRNP biogenesis, transport, or recycling. Here we describe that... |
9710562 | Engineering of a minimal modular polyketide synthase, and targeted alteration of the stereospecificity of polyketide chain extension. | <h4>Background</h4>Polyketides are a large and structurally diverse group of natural products that include antibiotics, antifungal agents and immunosuppressant compounds. Polyketides are biosynthesised in filamentous bacteria on modular polyketide synthases (PKSs) in which each cycle of chain extension requires a diffe... |
9721973 | Systemic inflammatory response syndrome (SIRS), multiple organ dysfunction syndrome (MODS), multiple organ failure (MOF): are we winning the battle? | The problems of inflammation and infection leading to organ dysfunction and failure continue to be the major problems after injury and operations and with intensive care for many diseases and problems. When SIRS goes to MODS and MOF, the mortality becomes high, ranging from 30-80% depending on the number of failed orga... |
9720046 | Conservation of the amino-terminal epitope of elongation factor Tu in eubacteria and Archaea. | An epitope of elongation factor Tu (EF-Tu), which is found in organisms in both the bacterial and archaeal domains, was recently defined by mAb 900. To localize the conserved epitope within the EF-Tu molecule and to determine its sequence, SPOTScan analysis of synthetic peptides, Western blot analysis of purified EF-Tu... |
9718308 | Relationship of membrane curvature to the formation of pores by magainin 2. | Magainin 2, an antimicrobial peptide from the Xenopus skin, kills bacteria by permeabilizing the cell membranes. We have proposed that the peptide preferentially interacts with acidic phospholipids to form a peptide-lipid supramolecular complex pore, which allows mutually coupled transbilayer traffic of ions, lipids, a... |
9714812 | Construction of new vectors for high-level expression in actinomycetes. | A new integrative vector (pCJR24) was constructed for use in the erythromycin producer Saccharopolyspora erythraea and in other actinomycetes. It includes the pathway-specific activator gene actII-ORF4 from the actinorhodin biosynthetic gene cluster of Streptomyces coelicolor. The actI promoter and the associated ribos... |
9715187 | Cellular injury score for multiple organ failure severity scoring system. | <h4>Background</h4>Cellular Injury Score (CIS) is an index of cellular injury, being calculated from three parameters of intracellular metabolism: arterial ketone body ratio, osmolality gap, and blood lactate.<h4>Methods</h4>The usefulness of CIS as a severity scoring system for patients with multiple organ failure was... |
9715186 | Multiple organ failure can be predicted as early as 12 hours after injury. | <h4>Background</h4>The failure of therapies aimed at modulating systemic inflammatory response syndrome and decreasing multiple organ failure (MOF) has been attributed in part to the inability to identify early the population at risk. Our objective, therefore, was to develop predictive models for MOF at admission and a... |
9712847 | Cholesterol depletion delocalizes phosphatidylinositol bisphosphate and inhibits hormone-stimulated phosphatidylinositol turnover. | Caveolae and detergent-insoluble, glycosphingolipid-enriched domains (DIGs) are cholesterol-enriched membrane domains that have been implicated in signal transduction because a variety of signaling proteins as well as phosphatidylinositol bisphosphate (PtdInsP2) are compartmentalized in these domains. We report here th... |
9714156 | Flexible docking allowing induced fit in proteins: insights from an open to closed conformational isomers. | Here we dock a ligand onto a receptor surface allowing hinge-bending domain/substructural movements. Our approach mimics and manifests induced fit in molecular recognition. All angular rotations are allowed on the one hand, while a conformational space search is avoided on the other. Rather than dock each of the molecu... |
9707626 | The m2 form of the Helicobacter pylori cytotoxin has cell type-specific vacuolating activity. | The Helicobacter pylori toxin VacA causes vacuolar degeneration in mammalian cell lines in vitro and plays a key role in peptic ulcer disease. Two alleles, m1 and m2, of the mid-region of the vacA gene have been described, and the m2 cytotoxin always has been described as inactive in the in vitro HeLa cell assay. Howev... |
9707570 | Mechanism of capsid maturation in a double-stranded DNA virus. | Folding mechanisms of proteins incorporated within supramolecular assemblies, including viruses, are little understood and may differ fundamentally from folding mechanisms of small globular proteins. We describe a novel Raman dynamic probe of hydrogen-isotope exchange to investigate directly these protein folding/assem... |
9707559 | A 1.3-A resolution crystal structure of the HIV-1 trans-activation response region RNA stem reveals a metal ion-dependent bulge conformation. | The crystal structure of an HIV-1 trans-activation response region (TAR) RNA fragment containing the binding site for the trans-activation protein Tat has been determined to 1.3-A resolution. In this crystal structure, the characteristic UCU bulge of TAR adopts a conformation that is stabilized by three divalent calciu... |
9707558 | New enzyme lineages by subdomain shuffling. | Protein functions have evolved in part via domain recombination events. Such events, for example, recombine structurally independent functional domains and shuffle targeting, regulatory, and/or catalytic functions. Domain recombination, however, can generate new functions, as implied by the observation of catalytic sit... |
9706061 | Evaluation of cytotoxicity of various ophthalmic drugs, eye drop excipients and cyclodextrins in an immortalized human corneal epithelial cell line. | <h4>Purpose</h4>An immortalized human corneal epithelial cell line (HCE) was tested as a screening tool for prediction of topical ocular irritation/toxicity by pharmaceuticals<h4>Methods</h4>Effects of various drugs, excipients and cyclodextrins (CDs) on viability of HCE cells were evaluated using two in vitro cytotoxi... |
9707114 | Design and self-assembly of two-dimensional DNA crystals. | Molecular self-assembly presents a 'bottom-up' approach to the fabrication of objects specified with nanometre precision. DNA molecular structures and intermolecular interactions are particularly amenable to the design and synthesis of complex molecular objects. We report the design and observation of two-dimensional c... |
9703464 | Structure-activity relationships and molecular modeling of 3, 5-diacyl-2,4-dialkylpyridine derivatives as selective A3 adenosine receptor antagonists. | The structure-activity relationships of 6-phenyl-1,4-dihydropyridine derivatives as selective antagonists at human A3 adenosine receptors have been explored (Jiang et al. J. Med. Chem. 1997, 39, 4667-4675). In the present study, related pyridine derivatives have been synthesized and tested for affinity at adenosine rec... |
9703463 | Synthesis and biological activity of a new series of N6-arylcarbamoyl, 2-(Ar)alkynyl-N6-arylcarbamoyl, and N6-carboxamido derivatives of adenosine-5'-N-ethyluronamide as A1 and A3 adenosine receptor agonists. | A new series of 1-(6-amino-9H-purin-9-yl)-1-deoxy-N-ethyl-beta-D-ribofuranuronamide++ +-b earing N-arylureas or N-arylcarboxamido groups at the purine 6 position and N-arylureas combined with halogens or alkynyl chains at the 2 position have been synthesized and tested for affinity at A1 and A2A adenosine receptors in ... |
9705135 | A stereological study of dorsal root ganglion cells and nerve root fibers from rats exposed to mercury vapor. | Although mercury vapor is known to produce tremor and peripheral neuropathy, neuropathological studies of the effects of the vapor are few in number. The aim of the present study has been to evaluate the effect of mercury vapor on the morphology of the dorsal root ganglion and the spinal nerve roots. Adult male rats we... |
9700157 | A membrane coat complex essential for endosome-to-Golgi retrograde transport in yeast. | We have recently characterized three yeast gene products (Vps35p, Vps29p, and Vps30p) as candidate components of the sorting machinery required for the endosome-to-Golgi retrieval of the vacuolar protein sorting receptor Vps10p (Seaman, M.N.J., E.G. Marcusson, J.-L. Cereghino, and S.D. Emr. 1997. J. Cell Biol. 137:79-9... |
9694863 | Cholesterol depletion of caveolae causes hyperactivation of extracellular signal-related kinase (ERK). | Previously we showed that activation of Erk in quiescent cells occurs in the caveolae fraction isolated from fibroblasts. Since the structure and function of caveolae is sensitive to the amount of cholesterol in the membrane, it might be that a direct link exists between the concentration of membrane cholesterol and mi... |
9696764 | The Escherichia coli citrate carrier CitT: a member of a novel eubacterial transporter family related to the 2-oxoglutarate/malate translocator from spinach chloroplasts. | Under anoxic conditions in the presence of an oxidizable cosubstrate such as glucose or glycerol, Escherichia coli converts citrate to acetate and succinate. Two enzymes are specifically required for the fermentation of the tricarboxylic acid, i.e., a citrate uptake system and citrate lyase. Here we report that the ope... |
9696762 | Influence of the secondary cell wall polymer on the reassembly, recrystallization, and stability properties of the S-layer protein from Bacillus stearothermophilus PV72/p2. | The high-molecular-weight secondary cell wall polymer (SCWP) from Bacillus stearothermophilus PV72/p2 is mainly composed of N-acetylglucosamine (GlcNAc) and N-acetylmannosamine (ManNAc) and is involved in anchoring the S-layer protein via its N-terminal region to the rigid cell wall layer. In addition to this binding f... |
9693377 | ATP- and cytosol-dependent release of adaptor proteins from clathrin-coated vesicles: A dual role for Hsc70. | Clathrin-coated vesicles (CCV) mediate protein sorting and vesicular trafficking from the plasma membrane and the trans-Golgi network. Before delivery of the vesicle contents to the target organelles, the coat components, clathrin and adaptor protein complexes (APs), must be released. Previous work has established that... |
9692995 | Origin of starter units for erythromycin biosynthesis. | Modular polyketide synthases (PKSs), such as the 6-deoxyerythronolide B synthase (DEBS), are multifunctional proteins that govern the synthesis of a number of clinically important natural products. The modular arrangement of active sites within these enzymes suggests the possibility of a combinatorial approach to the s... |
9692987 | Recombinant soluble human alpha 3 beta 1 integrin: purification, processing, regulation, and specific binding to laminin-5 and invasin in a mutually exclusive manner. | Using insect cells, we expressed large quantities of soluble human integrin alpha 3 beta 1 ectodomain heterodimers, in which cytoplasmic and transmembrane domains were replaced by Fos and Jun dimerization motifs. In direct ligand binding assays, soluble alpha 3 beta 1 specifically bound to laminin-5 and laminin-10, but... |
9693115 | Expression, characterization and engineered specificity of rat epididymal retinoic acid-binding protein. | Epididymal retinoic acid-binding protein (ERABP) is the major androgen-dependent protein present in the lumen of the epididymis and is thought to be involved in sperm maturation. It displays a high degree of three-dimensional structural similarity to serum retinol-binding protein (RBP). Although both proteins interact ... |
9693103 | Site-directed mutations in fungal laccase: effect on redox potential, activity and pH profile. | A Myceliophthora thermophila laccase and a Rhizoctonia solani laccase were mutated on a pentapeptide segment believed to be near the type-1 Cu site. The mutation L513F in Myceliophthora laccase and the mutation L470F in Rhizoctonia laccase took place at a position corresponding to the type-1 Cu axial methionine (M517) ... |
9689087 | Underlying assumptions of developmental models. | These 10 obvious propositions make a model of the specification of form, intended to expose underlying assumptions of developmental biology for examination and future experimentation. (I) The control of development is by means of local interactions, rather than global control mechanisms. (II) A macromolecule near a spe... |
9689064 | Cocaine alters the accessibility of endogenous cysteines in putative extracellular and intracellular loops of the human dopamine transporter. | Cocaine and other psychostimulants act by blocking the dopamine transporter. Binding of the cocaine analog, [3H]2-beta-carbomethoxy-3-beta-(4-fluorophenyl) tropane (CFT) to the dopamine transporter is sensitive to polar sulfhydryl-specific derivatives of methanethiosulfonate (MTS). These reagents preferentially react w... |
9691026 | In vivo identification of intermediate stages of the DNA inversion reaction catalyzed by the Salmonella Hin recombinase. | The Hin recombinase catalyzes a site-specific recombination reaction that results in the reversible inversion of a 1-kbp segment of the Salmonella chromosome. The DNA inversion reaction catalyzed by the Salmonella Hin recombinase is a dynamic process proceeding through many intermediate stages, requiring multiple DNA s... |
9687335 | Increased shelf-life of fosphenytoin: solubilization of a degradant, phenytoin, through complexation with (SBE)7m-beta-CD. | Fosphenytoin, a water-soluble prodrug of phenytoin, degrades primarily to phenytoin at pH values <8 during long term storage; phenytoin readily precipitates when formed from fosphenytoin due to its limited aqueous solubility. The objective of this study was to develop stable formulations of fosphenytoin in the pH range... |
9687493 | Structure, function and tissue forms of the C-terminal globular domain of collagen XVIII containing the angiogenesis inhibitor endostatin. | The C-terminal domain NC1 of mouse collagen XVIII (38 kDa) and the shorter mouse and human endostatins (22 kDa) were prepared in recombinant form from transfected mammalian cells. The NC1 domain aggregated non-covalently into a globular trimer which was partially cleaved by endogenous proteolysis into several monomers ... |
9687463 | Phage display of a biologically active Bacillus thuringiensis toxin. | Activated forms of Bacillus thuringiensis insecticidal toxins have consistently been found to form insoluble and inactive precipitates when they are expressed in Escherichia coli. Genetic engineering of these proteins to improve their effectiveness as biological pesticides would be greatly facilitated by the ability to... |
9687389 | Site-specific mutations in the 23S rRNA gene of Helicobacter pylori confer two types of resistance to macrolide-lincosamide-streptogramin B antibiotics. | Clarithromycin resistance in Helicobacter pylori is mainly due to A-to-G mutations within the peptidyltransferase region of the 23S rRNA. In the present study, cross-resistance to macrolide, lincosamide, and streptogramin B (MLS) antibiotics (MLS phenotypes) has been investigated for several clinical isolates of H. pyl... |
9685503 | 2-Aminopurine fluorescence studies of base stacking interactions at abasic sites in DNA: metal-ion and base sequence effects. | Metal-ion and sequence dependent changes in the stacking interactions of bases surrounding abasic (AB) sites in 10 different DNA duplexes were examined by incorporating the fluorescent nucleotide probe 2-aminopurine (2-AP), opposite to the site (AB-APopp) or adjacent to the site (AB-APadj) on either strand. A detailed ... |
9685654 | Metyrapone pretreatment prevents the behavioral and neurochemical sequelae induced by stress. | In the present study, we examined the effect of metyrapone, an inhibitor of corticosterone (CS) synthesis, on the behavioral and neurochemical sequelae induced by a brief restraint session. A 15-min stress period induced an anxiogenic-like behavior on the elevated plus-maze (EPM), which was reversed with metyrapone (75... |
9683613 | Smith-Lemli-Opitz syndrome is caused by mutations in the 7-dehydrocholesterol reductase gene. | Smith-Lemli-Opitz syndrome is a frequently occurring autosomal recessive developmental disorder characterized by facial dysmorphisms, mental retardation, and multiple congenital anomalies. Biochemically, the disorder is caused by deficient activity of 7-dehydrocholesterol reductase, which catalyzes the final step in th... |
9683494 | Genetic analysis of dioxin dioxygenase of Sphingomonas sp. Strain RW1: catabolic genes dispersed on the genome. | The dioxin dioxygenase of Sphingomonas sp. strain RW1 activates dibenzo-p-dioxin and dibenzofuran for further metabolism by introducing two atoms of oxygen at a pair of vicinal carbon atoms, one of which is involved in one of the bridges between the two aromatic rings, i.e., an angular dioxygenation. The dxnA1 and dxnA... |
9683485 | YscO of Yersinia pestis is a mobile core component of the Yop secretion system. | The Yersinia pestis low-Ca2+ response stimulon is responsible for the temperature- and Ca2+-regulated expression and secretion of plasmid pCD1-encoded antihost proteins (V antigen and Yops). We have previously shown that lcrD, yscC, yscD, yscG, and yscR encode proteins that are essential for high-level expression and s... |
9680483 | Insights into the mechanism of heterodimerization from the 1H-NMR solution structure of the c-Myc-Max heterodimeric leucine zipper. | The oncoprotein c-Myc (a member of the helix-loop-helix-leucine zipper (b-HLH-LZ) family of transcription factors) must heterodimerize with the b-HLH-LZ Max protein to bind DNA and activate transcription. It has been shown that the LZ domains of the c-Myc and Max proteins specifically form a heterodimeric LZ at 20 degr... |
9677311 | Tryprostatin A, a specific and novel inhibitor of microtubule assembly. | We have investigated the cell cycle inhibition mechanism and primary target of tryprostatin A (TPS-A) purified from Aspergillus fumigatus. TPS-A inhibited cell cycle progression of asynchronously cultured 3Y1 cells in the M phase in a dose- and time-dependent manner. In contrast, TPS-B (the demethoxy analogue of TPS-A)... |
9675213 | Oligomeric state of human erythrocyte band 3 measured by fluorescence resonance energy homotransfer. | The oligomeric state of the erythrocyte anion exchange protein, band 3, has been assayed by resonance energy homotransfer. Homotransfer between oligomeric subunits, labeled with eosin-5-maleimide at Lys430 in the transmembrane domain, has been demonstrated by steady-state and time-resolved fluorescence spectroscopy, an... |
9675205 | Characterization of lipid DNA interactions. I. Destabilization of bound lipids and DNA dissociation. | We have recently described a method for preparing lipid-based DNA particles (LDPs) that form spontaneously when detergent-solubilized cationic lipids are mixed with DNA. LDPs have the potential to be developed as carriers for use in gene therapy. More importantly, the lipid-DNA interactions that give rise to particle f... |
9675203 | A spectroscopic and thermodynamic study of porphyrin/DNA supramolecular assemblies. | Assemblies of trans-bis(N-methylpyridinium-4-yl)diphenylporphine ions on the surface of calf thymus DNA have been studied using several spectroscopic techniques: absorbance, circular dichroism, and resonance light scattering. The aggregation equilibrium can be treated as a two-state system-monomer and assembly-each bou... |
9675199 | Trematode hemoglobins show exceptionally high oxygen affinity. | Ligand binding studies were made with hemoglobin (Hb) isolated from trematode species Gastrothylax crumenifer (Gc), Paramphistomum epiclitum (Pe), Explanatum explanatum (Ee), parasitic worms of water buffalo Bubalus bubalis, and Isoparorchis hypselobagri (Ih) parasitic in the catfish Wallago attu. The kinetics of oxyge... |
9675198 | Circular dichroism of DNA frayed wires. | Ultraviolet circular dichroism spectra are reported for the oligonucleotide d(A15G15) in aqueous solutions containing 5 mM MgCl2 at several temperatures and in the presence of partially complementary oligonucleotides. Oligonucleotides with several consecutive terminal guanine residues self-associate to form aggregates,... |
9675177 | Hydration and conformational equilibria of simple hydrophobic and amphiphilic solutes. | We consider whether the continuum model of hydration optimized to reproduce vacuum-to-water transfer free energies simultaneously describes the hydration free energy contributions to conformational equilibria of the same solutes in water. To this end, transfer and conformational free energies of idealized hydrophobic a... |
9675173 | Topological defects and the optimum size of DNA condensates. | Under a wide variety of conditions, the addition of condensing agents to dilute solutions of random-coil DNA gives rise to highly compact particles that are toroidal in shape. The size of these condensates is remarkably constant and is largely independent of DNA molecular weight and basepair sequence, and of the nature... |
9673293 | Vag8, a Bordetella pertussis bvg-regulated protein. | Bordetella pertussis expresses a bvg-regulated 95-kDa protein, Vag8, encoded by vag-8. Southern blot analysis indicates that strains of Bordetella bronchiseptica and Bordetella parapertussis have DNA homologous to vag-8. Antiserum raised to a fusion of maltose binding protein to an N-terminal 60-kDa fragment of Vag8 re... |
9673272 | The globoseries glycosphingolipid sialosyl galactosyl globoside is found in urinary tract tissues and is a preferred binding receptor In vitro for uropathogenic Escherichia coli expressing pap-encoded adhesins. | Women with a history of recurrent Escherichia coli urinary tract infections (UTIs) are significantly more likely to be nonsecretors of blood group antigens than are women without such a history, and vaginal epithelial cells (VEC) from women who are nonsecretors show enhanced adherence of uropathogenic E. coli isolates ... |
9673238 | Iron starvation of Bordetella avium stimulates expression of five outer membrane proteins and regulates a gene involved in acquiring iron from serum. | Iron starvation of Bordetella avium induced expression of five outer membrane proteins with apparent molecular masses of 95, 92, 91.5, 84, and 51 kDa. Iron-responsive outer membrane proteins (FeRPs) of similar sizes were detected in six of six strains of B. avium, suggesting that the five FeRPs are common constituents ... |
9671475 | Introduction of hereditary disease-associated mutations into the beta-amyloid precursor protein gene of mouse embryonic stem cells: a comparison of homologous recombination methods. | Two different approaches for introducing pathogenic mutations into the beta-amyloid precursor protein gene in mouse embryonic stem cells were compared. Both approaches require two sequential modifications of the targeting locus by homologous recombinations. One approach was a "targeting-in-out" procedure that is based ... |
9664032 | Assembly of connexins and MP26 in lens fiber plasma membranes studied by SDS-fracture immunolabeling. | The SDS-fracture immunolabeling technique, unlike conventional freeze-fracture, provides direct evidence for the biochemical nature of membrane constituents. SDS-fracture immunolabeling shows that during differentiation of lens fiber cells the onset of junctional assembly is characterized by the presence of small clust... |
9658146 | Interleukin-12 p40 mRNA expression in bovine leukemia virus-infected animals: increase in alymphocytosis but decrease in persistent lymphocytosis. | Interleukin-12 (IL-12), a key cytokine in immune regulation, has an important role in activating the cell-mediated immune response in infectious diseases. Recently, a dichotomy between IL-12 and IL-10 regarding progression of a variety diseases has emerged. IL-12 activates type 1 cytokine production and has an antagoni... |
9658121 | Complete protein linkage map of poliovirus P3 proteins: interaction of polymerase 3Dpol with VPg and with genetic variants of 3AB. | Poliovirus has evolved to maximize its genomic information by producing multifunctional viral proteins. The P3 nonstructural proteins harbor various activities when paired with different binding partners. These viral polypeptides regulate host cell macromolecular synthesis and function as proteinases, as RNA binding pr... |
9658117 | Viral ribonucleoprotein complex formation and nucleolar-cytoplasmic relocalization of nucleolin in poliovirus-infected cells. | The poliovirus 3' noncoding region (3'NCR) is involved in the efficient synthesis of viral negative-stranded RNA molecules. A strong interaction between a 105-kDa host protein and the wild-type 3'NCR, but not with a replication-defective mutant 3'NCR, was detected. This 105-kDa protein was identified as nucleolin which... |
9658077 | Molecular mechanisms of serum resistance of human influenza H3N2 virus and their involvement in virus adaptation in a new host. | H3N2 human influenza viruses that are resistant to horse, pig, or rabbit serum possess unique amino acid mutations in their hemagglutinin (HA) protein. To determine the molecular mechanisms of this resistance, we characterized the receptor-binding properties of these mutants by measuring their affinity for total serum ... |
29711521 | Organometallic Triskelia: Novel Tris(vinylideneruthenium(II)), Tris(alkynylruthenium(II)), and Triruthenium-Triferrocenyl Complexes. | Incorporation of a redox-passive bridge affords three identical redox systems in the triskelion-shaped, carbon-rich, polyvinylidenemetal complex 1. The complex was isolated from the activation of the tripodal polyyne 1,3,5-(HC≡CC<sub>6</sub> H<sub>4</sub> C≡C)<sub>3</sub> C<sub>6</sub> H<sub>3</sub> with [RuCl<sub>2</s... |
29711515 | A New Base-Pairing Motif Based on Modified Guanosines. | Stable even in dimethyl sulfoxide, dimer I does not dissociate to monomers 1 in organic media. The unique base-pairing interaction involving four hydrogen bonds in the readily available compound 1 was characterized by NMR spectroscopy. |
29711507 | Ring-Closing Metathesis of Functionalized Acetylene Derivatives: A New Entry into Cycloalkynes. | A tungsten alkylidyne catalyst is the key to achieving ring-closing metatheses of diynes to form functionalized macrocycles [Eq. (a)]. Partial reduction of the cycloalkynes provides stereoselective Z-configured cycloalkenes, which are currently inaccessible by conventional alkene metathesis. |
21644769 | Potentiometric detection of alkali and alkaline Earth metal cations in capillary electrophoresis with simplified electrode alignment and enhanced separation and sensitivity. | Coated-wire electrodes were employed as potentiometric detectors for the analysis of alkali and alkaline earth metals by capillary electrophoresis. Easy electrode alignment was achieved by a Plexiglas capillary-electrode holder, which makes it unnecessary to employ a microscope and a micromanipulator. The addition of a... |
21644765 | Hydrophilic interaction chromatography-electrospray mass spectrometry analysis of polar compounds for natural product drug discovery. | For the drug discovery efforts currently taking place within the pharmaceutical industry, natural product extracts have been found to provide a valuable source of molecular diversity which is complementary to that provided by traditional synthetic organic methods or combinatorial chemistry. However, there exists a need... |
19649786 | Predicting ligand binding energies. | Computer-aided drug design is a burgeoning discipline, in part, because of the fundamental role that molecular recognition plays in chemistry and biology, and partly due to the obvious commercial implications. This review focuses on methods rather than applications and a selection of novel techniques for predicting lig... |
18408295 | Pathogenesis of acute renal failure: shock-kidneys. | Causes of acute renal failure (ARF) are summarized. The article focuses on "shock kidneys" as they occur following traumatic or septic shock. There may be low-grade intermittent but persisting endotoxemia in the former together with other factors like rhabdomyolysis, and marked endotoxemia at least for a few hours in t... |
17029729 | Self-assembly of melanin studied by laser light scattering. | The unknown molecular weight and chemical structure of melanin place the study of these pigments outside the range of the classical biochemical techniques; thus in this paper the problem of characterizing these heterogeneous biopolymers was approached by means of light scattering techniques, static and dynamic. The sta... |
9680444 | The Melt Viscosity of Dendritic Poly(benzyl ether) Macromolecules. | The zero shear melt viscosity, eta0, for a variety of dendritic poly(benzyl ether) macromolecules has been measured. The viscosity of low generation dendrimers exhibits a strong molecular mass, M, dependence, yet, direct proportionality between eta0 and M is observed at higher generations. The viscosity scales with M f... |
9680408 | A Novel Synthesis of Poly(ester-alt-sulfide)s by the Ring-Opening Alternating Copolymerization of Oxiranes with gamma-Thiobutyrolactone Using Quaternary Onium Salts or Crown Ether Complexes as Catalysts. | Poly(ester-alt-sulfide) (polymer 1) was synthesized by the alternating copolymerization of glycidyl phenyl ether (GPE) with gamma-thiobutyrolactone (TBL) catalyzed by either quaternary onium salts or crown ether complexes. The copolymerization proceeded to produce polymer 1 with good yields in neat or in various organi... |
9677189 | Rotation of a single molecule within a supramolecular bearing | Experimental visualization and verification of a single-molecule rotor operating within a supramolecular bearing is reported. Using a scanning tunneling microscope, single molecules were observed to exist in one of two spatially defined states laterally separated by 0.26 nanometers. One was identified as a rotating sta... |
11670493 | Intense Photosensitized Emission from Stoichiometric Compounds Featuring Mn(2+) in Seven- and Eightfold Coordination Environments. | Synthetic, structural and luminescence studies of stoichiometric crown ether compounds of Mn(2+) in well-defined coordination environments were undertaken in an effort to understand the origin of emitting crystal defects found in cubic F23 [(K18C6)(4)MnBr(4)][TlBr(4)](2) crystals (Fender, N. S.; et al. Inorg. Chem. 199... |
11670475 | Dithiocarbamate-Functionalized Dendrimers as Ligands for Metal Complexes. | Zeroth- and first-generation poly(amido)amine dendrimers have been functionalized with dithiocarbamate end groups and reacted with ruthenium complexes, to form metallodendrimers. Monomeric ruthenium dithiocarbamate complexes were also prepared as model compounds and their spectroscopic data compared with those of the m... |
11670469 | Structural, EPR, and Electrochemical Studies of Binuclear Copper(II) Complexes of Bis(pentadentate) Ligands Derived from Bis(1,4,7-triazacyclonane) Macrocycles. | Structural, electrochemical, and EPR studies of binuclear copper(II) complexes of bis(pentadentate) ligands, obtained by attaching 2-pyridylmethyl arms to the four secondary nitrogens of bis(tacn) macrocycles linked by ethyl (tmpdtne, [Cu(2)(tmpdtne)](ClO(4))(4).2H(2)O 2), propyl (tmpdtnp, [Cu(2)(tmpdtnp)](ClO(4))(4) 3... |
11670465 | Heterometallic Homo- and Heteroleptic Porphyrinate Dimers with a Rhodium-Thallium Bond. | The synthesis and spectroscopic characterization of four heterometallic porphyrinate dimers containing rhodium-thallium metal-metal bonds are reported. The investigated compounds are represented by the formula (Porph)Rh-Tl(Porph'), where Porph and Porph' are OEP and/or TPP. UV/visible spectroscopy of the title complexe... |
11670438 | Calixarenes Derivatized with Sulfur-Containing Functionalities as Selective Extractants for Heavy and Precious Metal Ions. | The calix[4]arenes 5,11,17,23-tert-butyl-25,26,27,28-(2-methylthioethoxy)calix[4]arene, 25,26,27,28-(2-methylthioethoxy)calix[4]arene, and 5,11,17,23-tert-butyl-25,26,27,28-(2-(2-thiophenecarboxy)ethoxy)calix[4]arene have been prepared. The structure of 25,26,27,28-(2-methylthioethoxy)calix[4]arene has been verified by... |
11670437 | [CuCN.Me(3)SnCN.0.5bpy] (bpy = 4,4'-Bipyridine): A Novel Supramolecular Assembly Involving the No Longer Unusual {Cu(2)(&mgr;-CN)(2)(CN)(2)} Motif. | Reaction of K(3)[Cu(CN)(4)] with Me(3)SnCl and 4,4'-bipyridine (bpy) affords the novel ternary adduct [CuCN.Me(3)SnCN.0.5bpy], 2, as yellow, cubelike crystals. The supramolecular architecture of 2 consists, according to a single-crystal X-ray study, of remarkably porous, approximately planar sheets held together by alm... |
11670435 | Structural and (99)Tc NMR Investigations of Complexes with fac-[Tc(CO)(3)](+) Moieties and Macrocyclic Thioethers of Various Ring Sizes: Synthesis and X-ray Structure of the Complexes fac-[Tc(9-ane-S(3))(CO)(3)]Br, fac-[Tc(2)(tosylate)(2)(18-ane-S(6))(CO)(6)], and fac-[Tc(2)(20-ane-S(6)-OH)(CO)(6)][tosylate](2). | Starting originally from the organometallic precursor [NEt(4)](2)[TcBr(3)(CO)(3)] (1b), substitution reactions were performed with the macrocyclic thioethers 1,4,7-trithiacyclononane (9-ane-S(3)), 1,4,7,10,13,16-hexathiacyclooctadecane (18-ane-S(6)), and 3,6,9,13,16,19-hexathiacycloicosanol (20-ane-S(6)-OH). The corres... |
12016885 | [Simultaneous determination of the enantiomers of verapamil and norverapamil in plasma by high performance capillary electrophoresis]. | An analytical method has been developed to determine simultaneously plasma concentration of the enantiomers of verapamil and its major metabolite, norverapamil, using capillary zone electrophoresis. Trimethyl-beta-cyclodextrin was selected as chiral selector. Good separation was achieved under the conditions as below: ... |
10474657 | Bioelectrorheological model of the cell. 8. Cellular deformation under prolonged and recurrent shear stress. | The influence of a prolonged and recurrent shear stress created by a periodic electric field on the mechanical properties of Neurospora crassa cells was investigated. Conditions were found under which modifications of cellular structures responding to stress become irreversible, and plastic flow of the viscoelastic str... |
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