id stringlengths 4 8 | title stringlengths 1 642 | abstract stringlengths 50 17.9k |
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29711019 | Silicon Phthalocyanines with Axial Dendritic Substituents. | Nonscattering glasses that are indefinitely stable with respect to crystallization can be prepared from the title compounds. In these solid solutions, the dendritic substituents effectively suppress interactions between the phthalocyanine units (see the structure depicted on the right). |
29711009 | Porphyrins Like Boron After All. | The central core and the macrocycle skeleton of porphyrins both offer room for boron, and a gap in the chemistry of nonmetal-containing porphyrins has now been filled. In one case a four-membered B<sub>2</sub> O<sub>2</sub> ring coordinates to a porphyrin cavity that has been distorted to a rectangle (A), and in the ot... |
29711008 | Polysaccharide Derivatives for Chromatographic Separation of Enantiomers. | The first resolution of enantiomers was performed 150 years ago-mechanically. Today a powerful method for carrying out this task is HPLC on polysaccharide derivatives as chiral stationary phases. Most racemates, from an analytical to a preparative scale, now appear to be resolved by this technique. As an example, the c... |
18967126 | Gas chromatographic characteristics and application studies of the stationary phase of CH-B-15-C-5. | In this paper, separations of organic compounds, such as, n-alkanes, alcohols, ethyl asters of C(1)-C(8) carboxylic acid, halogen derivatives, position-isomers of the replacement aromatic hydrocarbon, optical isomers of ethyl lactate and isoamyl alcohol, etc. were studied using 4'-cholestenoxycarbonyl-benzo-15-crown-5 ... |
10099268 | Cyclodextrin effects on the ex-situ bioremediation of a chronically polychlorobiphenyl-contaminated soil | The possibility of enhancing the intrinsic ex-situ bioremediation of a chronically polychlorinated biphenyl-contaminated soil by using cyclodextrins was studied in this work. The soil, contaminated with a large array of polychlorinated biphenyls and deriving from a dump site where it has been stored for about 10 years,... |
9632897 | Stress protein of cyanobacteria CP36: interaction with photoactive complexes and formation of supramolecular structures | Cyanobacterium Anacystis nidulans R2, Synechocystis sp. PCC 6803 (wild-type strain and mutants Delta2 and Delta3 lacking PSII and PSI, respectively), and Synechocystis sp. BO 9201 synthesize the pigment--protein complex CP36 (CPIV-4, CP43') under iron deficiency in the medium. Accumulation of CP36 is accompanied by str... |
9600902 | Is polarization important in cation-pi interactions? | The importance of cation->aromatic polarization effects on cation-pi interactions has been explored. Theoretical calculations demonstrate that polarization is a large contribution to cation-aromatic interactions, and particularly to cation-pi interactions. For a series of compounds with a similar aromatic core, polariz... |
11670364 | Substituent-Induced Perturbation Symmetries and Distortions of meso-tert-Butylporphyrins. | The out-of-plane and in-plane distortions of a series of nickel(II) meso-substituted porphyrins with 0, 1, 2, or 4 tert-butyl groups [nickel(II) porphine (NiP), nickel(II) mono-tert-butylporphyrin (NiMtBuP), nickel(II) di-tert-butylporphyrin (NiDtBuP), and nickel(II) tetra-tert-butylporphyrin (NiTtBuP)] are investigate... |
12567960 | [Study on the inclusion of isodoniol-beta-cyclodextrin]. | The inclusion compound of isodoniol-beta-cyclodextrin was prepared by the liquidphase method in aqueous solution. And it was confirmed by thinlayer chromatography, differentical thermal analysis and specific rotation. The change (delta A) of ultraviolet spectrum was determined. The composition ratio of the inclusion co... |
12017004 | [Host-guest molecule interaction mechanism of hemostatics with liposomes and red blood cells studied with fluorescence polarimetric method]. | The supermolecule compounds of adrenobazone, p-aminomethylbenzoic acid, vitamin K1, 6-amino caproic acid with liposomes and red blood cells were studied by fluorescence polarimetric method. The mechanisms of formation of the supermolecule compounds were examined by fluorescence probe of the link of 1,6-dipheny-1,3,5-he... |
10797881 | Determination of drugs used as anti-Parkinson's disease drugs in urine and serum by capillary electrophoresis. | A new capillary electrophoresis method to determine simultaneously eight of the most important anti-Parkinson's disease compounds has been developed. The generic names of the drugs studied are benactyzine (BA), trihexyphenidyl (TP), fenpiverin (FP), diphemin (DF), scopolamine (BL), adiphenine (TS), diethylaminoethylest... |
10797879 | Determination of related impurities of bile acids in bulk drugs by cyclodextrin-modified micellar electrokinetic chromatography. | A cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC) method has been developed and validated for purity determination of two bile acids, ursodeoxycholic acid (UDCA) and deoxycholic acid (DCA). Quantitation of related impurities such as lithocholic acid (LCA), chenodeoxycholic acid (CDCA), cholic aci... |
10797874 | Determination of short-chain free fatty acids in lipolyzed milk fat by capillary electrophoresis. | The objective of this study was to monitor the release of short-chain free fatty acids (FFA) from milk fat during hydrolysis with lipase using capillary electrophoresis. Sample and run buffer allowed FFA to be maintained in solution by using cyclodextrin and methanol. Indirect UV detection at 270 nm was used, employing... |
9881754 | Conformational properties of a cycle oligosaccharide: cyclotrikis-(1-->6)-[alphaD-glucopyranosyl-(1-->4)-beta-D-glucopyranosy l]. | The title compound is a cyclic oligosaccharide having six glucopyranose residues linked alternatively by alpha-(1-->4) and beta-(1-->6) glycosidic linkages. Like cyclodextrin analogues it is expected to exhibit an internal cavity and to form inclusion complexes with other species. In order to investigate its conformati... |
9848178 | [Effect of preincubation on smooth muscle myosin light chain kinase activity]. | Phosphorylation of myosin regulatory light chain (RLC) catalysed by myosin light chain kinase (MLCK) is a key reaction in the regulation of actin-myosin interaction in smooth muscle. The activation of MLCK by calmodulin (CaM) and Ca2+ was investigated over a wide range of the enzyme concentrations using myosin or its R... |
9708333 | Tri-N-Boc-tetraazamacrocycle-nucleoside conjugates: synthesis and anti-HIV activities. | As far as linear N-Boc-polyamines conjugates elicited remarkable anti-HIV activity, the synthesis and anti-HIV properties of cyclic N-Boc-polyamines conjugates such as tetraazamacrocycle-nucleoside were studied. These new conjugates include an ester linkage between the two moieties. They were synthesized using Benzotri... |
9689900 | Interaction of per 3,6-anhydro-alpha cyclodextrins (alpha 36CD) and lead-alpha 36CD complex with biological systems. | The interactions of per (3,6 anhydro) alpha cyclodextrin (alpha 36CD) and of lead-alpha 36CD complex with biological systems were tested by NMR, ESR and electronic microscopy using erythrocytes and model membranes. It was found that the haemolytic activity of alpha 36CD alone was seven fold lower than that of natural a... |
9659176 | Autoantibodies against subunits of pyruvate dehydrogenase and citrate synthase in a case of paediatric biliary cirrhosis. | In a newborn girl with a history of connatal liver damage, histological examination of a liver biopsy sample taken during the seventh week of life revealed incipient destruction of bile ducts. Very high titres of antimitochondrial antibodies were later detected in the plasma. As the hepatic injury tended towards fibros... |
9657252 | The inflammatory basis of trauma/shock-associated multiple organ failure. | Multiple alterations in inflammatory and immunologic function have been demonstrated in clinical and experimental situations after trauma and hemorrhage, in particular the activation of various humoral (e.g. complement, coagulation) and cellular systems (neutrophils, endothelial cells, macrophages). As a consequence of... |
9654975 | [Epidemiology, clinical aspects and prognosis of severe progressive community-acquired pneumonia]. | <h4>Background</h4>Community-acquired pneumonia can lead to acute lung failure (parapneumonic ARDS) if the course is very severe. The clinical picture reflects a rapidly progressive and potentially fatal respiratory failure. Only occasional cases in which the clinical courses of community-acquired pneumonia lead to acu... |
9655636 | Two similar peptides from the venom of the scorpion Pandinus imperator, one highly effective blocker and the other inactive on K+ channels. | Two novel peptides, named Pi4 and Pi7, were purified from the venom of the scorpion Pandinus imperator, and their primary structures were determined. These peptides have 38 amino acids residues, compacted by four disulfide bridges, instead of the normal three found in most K+-channel specific toxins. Both peptides cont... |
9654080 | DNA-binding properties of the tandem HMG boxes of high-mobility-group protein 1 (HMG1). | High-mobility-group protein 1 (HMG1) is a conserved chromosomal protein with two homologous DNA-binding HMG-box domains, A and B, linked by a short basic region to an acidic carboxy-terminal tail. NMR spectroscopy on the free didomain (AB) shows that the two HMG boxes do not interact. The didomain has a higher affinity... |
9654055 | Engineering of factors determining alpha-amylase and cyclodextrin glycosyltransferase specificity in the cyclodextrin glycosyltransferase from Thermoanaerobacterium thermosulfurigenes EM1. | The starch-degrading enzymes alpha-amylase and cyclodextrin glycosyltransferase (CGTase) are functionally and structurally closely related, with CGTases containing two additional domains (called D and E) compared to the three domains of alpha-amylases (A, B and C). Amino acid residue 196 (Thermoanaerobacterium thermosu... |
9652191 | Adenosine A3 receptors: novel ligands and paradoxical effects. | The physiological role of the adenosine A3 receptor is being investigated using newly synthesized, selective ligands. Recently, in addition to agonists, selective antagonists have been developed that belong to three distinct, non-purine chemical classes: flavonoids, 1,4-dihydropyridine derivatives (e.g. MRS1191, which ... |
9652121 | Separation of ergot alkaloids and their epimers and determination in sclerotia by capillary electrophoresis. | Capillary electrophoresis has been shown to be a very useful analysis technique for secondary metabolites of plants. In the present study a method is described for the qualitative and quantitative determination of ergot alkaloids and their epimers. The extraction from the biological matrix yields recoveries of 50-97%, ... |
9652897 | Hereditary angioneurotic edema and thromboembolic diseases: I: How symptoms of acute attacks change with aging. | Localized edema of the larynx and pharynx leading to death from asphyxia has long been recognized as a characteristic symptom of hereditary angioneurotic edema (HANE). Long-term follow-up of younger HANE patients has revealed that transient localized acute attacks of edema affect tissues where the microcirculation main... |
9652760 | SupraMolecular BioVectors (SMBV) improve antisense inhibition of erbB-2 expression. | New therapeutic strategies are now being developed against adenocarcinoma associated with erbB-2 amplification, particularly by inhibiting p185erbB-2 expression. Antisense oligodeoxynucleotides seem promising for this purpose as long as they are efficiently protected against degradation and targeted into the cells. We ... |
9645223 | Mechanisms controlling cellular suicide: role of Bcl-2 and caspases. | Apoptosis is an essential and highly conserved mode of cell death that is important for normal development, host defense and suppression of oncogenesis. Faulty regulation of apoptosis has been implicated in degenerative conditions, vascular diseases, AIDS and cancer. Among the numerous proteins and genes involved, memb... |
9645221 | Screening of conformationally constrained random polypeptide libraries displayed on a protein scaffold. | The selection of novel proteins or enzymes from random protein libraries has come to be a major objective in current biology, and these enzymes should prove useful in various biological and biomedical fields. New technologies such as in vitro selection of proteins in cell-free systems have high potential to realize evo... |
9644953 | ["Open abdomen" in the treatment of necrosis in acute pancreatitis]. | Eleven cases of acute necrotic pancreatitis had been treated by "open abdomen" at the author's departments. Nine patients survived, but 2 patients had been lost in MOF. Indication, technics and complications are discussed. The author's opinion is, that--on the basis of a suitable indication--"open abdomen" is a good me... |
9641552 | Respiratory and cardiovascular effects of the mu-opioid receptor agonist [Lys7]dermorphin in awake rats. | 1. Changes in respiratory variables, arterial blood pressure and heart rate were studied in awake rats after injection of the opioid peptide [Lys7]dermorphin and its main metabolites, [1-5]dermorphin and [1-4]dermorphin. 2. Fifteen minutes after injection, doses of [Lys7]dermorphin producing antinociception (i.c.v., 36... |
9632898 | Changes in E. coli inorganic pyrophosphatase structure induced by binding of metal activators. | The three-dimensional structures of E. coli inorganic pyrophosphatase (PPase) and its complexes with Mn2+ in a high affinity site and with Mg2+ in high and low affinity sites determined by authors in 1994-1996 at 1.9-2.2 A resolution are compared. Metal ion binding initiates the shifts of alpha-carbon atoms and of func... |
9630335 | Competitive and selective antagonism of P2Y1 receptors by N6-methyl 2'-deoxyadenosine 3',5'-bisphosphate. | The antagonist activity of N6-methyl 2'-deoxyadenosine 3',5'-bisphosphate (N6MABP) has been examined at the phospholipase C-coupled P2Y1 receptor of turkey erythrocyte membranes. N6MABP antagonized 2MeSATP-stimulated inositol phosphate hydrolysis with a potency approximately 20 fold greater than the previously studied ... |
9629908 | Dual chiral recognition system involving cyclodextrin derivatives in capillary electrophoresis II. Enhancement of enantioselectivity. | The enantiomer separation of hexobarbital was investigated by open tubular electrochromatography (OTEC) using the chiral stationary phase (CSP) CHIRASIL-DEX (a permethylated beta-cyclodextrin covalently linked to a dimethylpolysiloxane) and by cyclodextrin-electrokinetic chromatogaphy (CD-EKC) using anionic beta-cyclod... |
9629907 | Enantioseparation of anaesthetic drugs by capillary zone electrophoresis using cyclodextrin-containing background electrolytes. | The enantiomers of five racemic anaesthetic drugs were resolved with cyclodextrins using capillary zone electrophoresis. Parameters which affected the chiral resolution, such as type and concentration of cyclodextrin, temperature, and addition of organic modifier were investigated. The results show that the enantiomeri... |
9629906 | Mixed-mode separation of polycyclic aromatic hydrocarbons (PAHs) in electrokinetic chromatography. | A mixed-mode separation technique has been developed and optimized for the separation of the 16 Environmental Protection Agency (EPA) priority polycyclic aromatic hydrocarbons (PAHs). The procedure utilized two different buffer additives as pseudo-stationary phases with different selectivities towards the analytes. Sod... |
9629899 | Affinity isoelectric focusing of human serum apolipoprotein B-containing lipoproteins on agarose gels with cyclodextrins. | In an attempt to subfractionate apolipoprotein B-containing lipoproteins (apoB-Lp), agarose isoelectric focusing (IEF) of apoB-Lp in human sera was carried out in the presence of two kinds of cyclodextrins (CDs), which have different affinities for cholesterol. ApoB-Lp in the agarose gels was detected by immunofixation... |
9626889 | Structure-activity relationship of macrocyclic and linear gadolinium chelates: investigation of transmetallation effect on the zinc-dependent metallopeptidase angiotensin-converting enzyme. | Transmetallation between commercially available solutions of gadolinium (Gd) chelates and the zinc (Zn)-dependent angiotensin-converting enzyme (ACE) was investigated. In vitro, the strongest inhibitions were observed for the linear Gd complexes, Gd diethylenetriamine pentaacetic acid (DTPA) bis-methylamide (BMA) (IC50... |
9623881 | The 2-5A system: modulation of viral and cellular processes through acceleration of RNA degradation. | The 2-5A system is an RNA degradation pathway that can be induced by the interferons (IFNs). Treatment of cells with IFN activates genes encoding several double-stranded RNA (dsRNA)-dependent synthetases. These enzymes generate 5'-triphosphorylated, 2',5'-phosphodiester-linked oligoadenylates (2-5A) from ATP. The effec... |
9619789 | Synthesis and physicochemical properties of lipophilic polyamide dendrimers. | <h4>Purpose</h4>To synthesise symmetrical dendritic macromolecules with external lipid surfaces, to investigate their behaviour at the air-water interface and their ability to form supramolecular aggregates, and to gain an understanding of their potential as drug carriers.<h4>Methods</h4>Dendrimeric compounds were synt... |
9619774 | In vitro myotoxicity of selected cationic macromolecules used in non-viral gene delivery. | <h4>Purpose</h4>Cationic lipid/DNA complexes have been proposed as a method of in vivo gene delivery via intravenous or intramuscular injection. A concern with using these polycationic molecules is whether they are associated with tissue toxicity at the injection site. Therefore, the objective of these studies was to i... |
9608435 | A computer-based expert system designs and analyzes a 2(k - p) fractional factorial design for the formulation optimization of novel multicomponent liposomes. | A computer-based technique based on a 2(k - p) fractional factorial design was applied for the optimization of recently described multicomponent protective liposomal formulations. These formulations contain sodium ascorbate (vitamin C) as a model drug sensitive to photochemical oxidation, as well as oil red O and/or ox... |
9608430 | HPLC determination of ketoprofen enantiomers in human serum using a nonporous octadecylsilane 1.5 microns column with hydroxypropyl beta-cyclodextrin as mobile phase additive. | A sensitive and stereospecific high-performance liquid chromatography (HPLC) method for the quantitation of ketoprofen enantiomers in human serum was developed. The assay involves the use of an octadecylsilane solid-phase extraction for serum sample clean-up prior to HPLC analysis. Chromatographic resolution of the ket... |
9605991 | The tumor necrosis factor-inducing potency of lipopolysaccharide and uronic acid polymers is increased when they are covalently linked to particles. | Lipopolysaccharide (LPS) and polymers of the uronic acid family stimulate monocytes to produce tumor necrosis factor (TNF). The TNF-inducing potency of these polysaccharides may depend on their supramolecular configuration. In this study detoxified LPS and uronic acid polymers have been covalently linked to particles w... |
9605326 | The role of tyrosine 121 in cofactor binding of 5-aminolevulinate synthase. | 5-Aminolevulinate synthase (EC 2.3.1.37) is the first enzyme in the heme biosynthesis in nonplant eukaryotes and some prokaryotes. It functions as a homodimer and requires pyridoxal 5'-phosphate as an essential cofactor. Tyr-121 is a conserved residue in all known sequences of 5-aminolevulinate synthases. Further, it c... |
9605317 | The role of polar interactions in the molecular recognition of CD40L with its receptor CD40. | CD40 Ligand (CD40L) is transiently expressed on the surface of T-cells and binds to CD40, which is expressed on the surface of B-cells. This binding event leads to the differentiation, proliferation, and isotype switching of the B-cells. The physiological importance of CD40L has been demonstrated by the fact that expre... |
9602323 | Effects of the pharmaceutical cosolvent hydroxypropyl-beta-cyclodextrin on porcine corneal endothelium. | <h4>Background</h4>The influence of the pharmaceutical cosolvent hydroxypropyl-beta-cyclodextrin (HPBCD) on porcine corneal endothelium was investigated. The purpose was to find out if this substance causes severe damage to the cornea. METHODS; One hundred and ninety-five pig corneas were preserved in Eagle's minimal e... |
9600988 | Cholesterol depletion inhibits the generation of beta-amyloid in hippocampal neurons. | The amyloid precursor protein (APP) plays a crucial role in the pathogenesis of Alzheimer's disease. During intracellular transport APP undergoes a series of proteolytic cleavages that lead to the release either of an amyloidogenic fragment called beta-amyloid (Abeta) or of a nonamyloidogenic secreted form consisting o... |
9600983 | Regulation of the pAD1 sex pheromone response of Enterococcus faecalis by direct interaction between the cAD1 peptide mating signal and the negatively regulating, DNA-binding TraA protein. | The Enterococcus faecalis conjugative plasmid pAD1 (60 kb) encodes a mating response to the recipient-produced peptide sex pheromone cAD1. The response involves two key plasmid-encoded regulatory proteins: TraE1, which positively regulates all or most structural genes relating to conjugation, and TraA, which binds DNA ... |
9600936 | Tyrosine kinase-dependent activation of a chloride channel in CD95-induced apoptosis in T lymphocytes. | CD95/Fas/APO-1 mediated apoptosis is an important mechanism in the regulation of the immune response. Here, we show that CD95 receptor triggering activates an outwardly rectifying chloride channel (ORCC) in Jurkat T lymphocytes. Ceramide, a lipid metabolite synthesized upon CD95 receptor triggering, also induces activa... |
9600905 | Two amino acid substitutions convert a guanylyl cyclase, RetGC-1, into an adenylyl cyclase. | Guanylyl cyclases (GCs) and adenylyl cyclases (ACs) have fundamental roles in a wide range of cellular processes. Whereas GCs use GTP as a substrate to form cGMP, ACs catalyze the analogous conversion of ATP to cAMP. Previously, a model based on the structure of adenylate cyclase was used to predict the structure of th... |
9601051 | Sequences within apolipoprotein(a) kringle IV types 6-8 bind directly to low-density lipoprotein and mediate noncovalent association of apolipoprotein(a) with apolipoprotein B-100. | Lipoprotein(a) [Lp(a)] particle formation is a two-step process in which initial noncovalent interactions between apolipoprotein(a) [apo(a)] and the apolipoprotein B-100 (apoB-100) component of low-density lipoprotein (LDL) precede disulfide bond formation. To identify kringle (K) domains in apo(a) that bind noncovalen... |
9599230 | Hydroxyphthalocyanines as potential photodynamic agents for cancer therapy. | A series of benzyl-substituted phthalonitriles, substituted at the 3-, 4-, and 4,5-positions, underwent varied condensations with phthalonitrile to give a series of protected (monohydroxy- and polyhydroxyphthalocyaninato)zinc(II) derivatives which were readily cleaved to give several hydroxyphthalocyanines (ZnPc) (phth... |
9593125 | In vitro activities of benzimidazoles against Echinococcus multilocularis metacestodes. | Alveolar echinococcosis, caused by the larval (metacestode) stage of the tapeworm Echinococcus multilocularis, is a lethal parasitosis of the liver prevalent in the Northern Hemisphere. For chemotherapy the benzimidazole derivatives mebendazole and albendazole were introduced, and their use has resulted in a significan... |
9593119 | Biological characterization of endotoxins released from antibiotic-treated Pseudomonas aeruginosa and Escherichia coli. | The supernatants taken from Pseudomonas aeruginosa and Escherichia coli cultures in human sera or chemically defined M9 medium in the presence of ceftazidime (CAZ) contained high levels of endotoxin, while those taken from the same cultures in the presence of imipenem (IPM) yielded a very low level of endotoxin. The bi... |
9584213 | Location of a high affinity Zn2+ binding site in the channel of alpha1beta1 gamma-aminobutyric acidA receptors. | Zn2+ inhibits currents through gamma-aminobutyric acid (GABA)A receptors. Its affinity depends on the subunit composition; alpha1beta1 receptors are inhibited with high affinity (IC50 = 0.54 micro M). We sought to identify the residues that form this high affinity Zn2+ binding site. beta1His267 aligns with alpha1Ser272... |
9585412 | Lipid domain structure of the plasma membrane revealed by patching of membrane components. | Lateral assemblies of glycolipids and cholesterol, "rafts," have been implicated to play a role in cellular processes like membrane sorting, signal transduction, and cell adhesion. We studied the structure of raft domains in the plasma membrane of non-polarized cells. Overexpressed plasma membrane markers were evenly d... |
9585411 | Ganglioside structure dictates signal transduction by cholera toxin and association with caveolae-like membrane domains in polarized epithelia. | In polarized cells, signal transduction by cholera toxin (CT) requires apical endocytosis and retrograde transport into Golgi cisternae and perhaps ER (Lencer, W.I., C. Constable, S. Moe, M. Jobling, H.M. Webb, S. Ruston, J.L. Madara, T. Hirst, and R. Holmes. 1995. J. Cell Biol. 131:951-962). In this study, we tested w... |
9585410 | Filipin-dependent inhibition of cholera toxin: evidence for toxin internalization and activation through caveolae-like domains. | The mechanism by which cholera toxin (CT) is internalized from the plasma membrane before its intracellular reduction and subsequent activation of adenylyl cyclase is not well understood. Ganglioside GM1, the receptor for CT, is predominantly clustered in detergent-insoluble glycolipid rafts and in caveolae, noncoated,... |
9585406 | Nucleocytoplasmic shuttling factors including Ran and CRM1 mediate nuclear export of NFAT In vitro. | We have developed a permeabilized cell assay to study the nuclear export of the shuttling transcription factor NFAT, which contains a leucine-rich export signal. The assay uses HeLa cells that are stably transfected with NFAT fused to the green fluorescent protein (GFP). Nuclear export of GFP-NFAT in digitonin-permeabi... |
9585405 | Evidence for a role of CLIP-170 in the establishment of metaphase chromosome alignment. | CLIPs (cytoplasmic linker proteins) are a class of proteins believed to mediate the initial, static interaction of organelles with microtubules. CLIP-170, the CLIP best characterized to date, is required for in vitro binding of endocytic transport vesicles to microtubules. We report here that CLIP-170 transiently assoc... |
9591688 | Characterization of the growth of 2D protein crystals on a lipid monolayer by ellipsometry and rigidity measurements coupled to electron microscopy. | We present here some sensitive optical and mechanical experiments for monitoring the process of formation and growth of two-dimensional (2D) crystals of proteins on a lipid monolayer at an air-water interface. The adsorption of proteins on the lipid monolayer was monitored by ellipsometry measurements. An instrument wa... |
9591686 | Protein modifications affecting triplet energy transfer in bacterial photosynthetic reaction centers. | The efficiency of triplet energy transfer from the special pair (P) to the carotenoid (C) in photosynthetic reaction centers (RCs) from a large family of mutant strains has been investigated. The mutants carry substitutions at positions L181 and/or M208 near chlorophyll-based cofactors on the inactive and active sides ... |
9591683 | The protein environment surrounding tyrosyl radicals D. and Z. in photosystem II: a difference Fourier-transform infrared spectroscopic study. | Photosystem II contains two redox-active tyrosine residues, termed D and Z, which have different midpoint potentials and oxidation/reduction kinetics. To understand the functional properties of redox-active tyrosines, we report a difference Fourier-transform infrared (FT-IR) spectroscopic study of these species. Vibrat... |
9591679 | A topological approach to nucleosome structure and dynamics: the linking number paradox and other issues. | The linking number paradox of DNA in chromatin (two negative crossings around the octamer, associated with a unit linking number reduction), which is 21 years old this year, has come of age. After stirring much debate in the past, the initially hypothetical explanation of the paradox by DNA overtwisting on the nucleoso... |
9570841 | Methyl-beta-cyclodextrins and liposomes as water-soluble carriers for cholesterol incorporation into membranes and its evaluation by a microenzymatic fluorescence assay and membrane fluidity-sensitive dyes. | A variety of methods to incorporate cholesterol into lipid membrane systems have been applied with varying success. We tested an incorporation method based on cholesterol-loaded methyl-beta-cyclodextrins and compared it to a method that uses cholesterol-loaded liposomes. With methyl-beta-cyclodextrin, we increased the ... |
9580700 | Oligomeric properties and DNA binding specificities of repressor isoforms from the Streptomyces bacteriophage phiC31. | Three protein isoforms (74, 54 and 42 kDa) are expressed from repressor gene c in the Streptomyces temperate bacteriophage phiC31. Because expression of the two smaller isoforms, 54 and 42 kDa, is sufficient for superinfection immunity, the interaction between these isoforms was studied. The native 42 kDa repressor (Na... |
9580689 | Step-wise DNA relaxation and decatenation by NaeI-43K. | Nae I protein was originally isolated for its restriction endonuclease properties. Nae I was later discovered to either relax or cleave supercoiled DNA, depending upon whether Nae I position 43 contains a lysine (43K) or leucine (43L) respectively. Nae I-43K DNA relaxation activity appears to be the product of coupling... |
9576904 | DNA ligands that bind tightly and selectively to cellobiose. | Cell surface oligosaccharides have been shown to play essential biological roles in such diverse biological phenomena as cellular adhesion, molecular recognition, and inflammatory response. The development of high-affinity ligands capable of selectively recognizing a variety of small motifs in different oligosaccharide... |
9576751 | Blockade of CC chemokine receptor 5 (CCR5)-tropic human immunodeficiency virus-1 replication in human lymphoid tissue by CC chemokines. | The CC chemokines MIP-1alpha, MIP-1beta, and RANTES suppress replication of certain HIV-1 strains in cultured PBMC and T cell lines by blocking interaction of gp120 with CC chemokine receptor 5 (CCR5). However, the same chemokines can enhance HIV-1 replication in cultured macrophages. The net effect of chemokines on HI... |
9576876 | Bile salts stimulate mucin secretion by cultured dog gallbladder epithelial cells independent of their detergent effect. | 1. Bile salts stimulate mucin secretion by the gallbladder epithelium. We have investigated whether this stimulatory effect is due to a detergent effect of bile salts. 2. The bile salts taurocholic acid (TC) and tauroursodeoxycholic acid (TUDC) and the detergents Triton X-100 (12.5-400 microM) and Tween-20 (0.1-3.2 mM)... |
9576857 | Release of the glycosylphosphatidylinositol-anchored enzyme ecto-5'-nucleotidase by phospholipase C: catalytic activation and modulation by the lipid bilayer. | Many hydrolytic enzymes are attached to the extracellular face of the plasma membrane of eukaryotic cells by a glycosylphosphatidylinositol (GPI) anchor. Little is currently known about the consequences for enzyme function of anchor cleavage by phosphatidylinositol-specific phospholipase C. We have examined this questi... |
9575185 | Molecular recognition of cyclic urea HIV-1 protease inhibitors. | As long as the threat of human immunodeficiency virus (HIV) protease drug resistance still exists, there will be a need for more potent antiretroviral agents. We have therefore determined the crystal structures of HIV-1 protease in complex with six cyclic urea inhibitors: XK216, XK263, DMP323, DMP450, XV638, and SD146,... |
9573161 | Joint transcriptional control of xpsR, the unusual signal integrator of the Ralstonia solanacearum virulence gene regulatory network, by a response regulator and a LysR-type transcriptional activator. | Ralstonia (Pseudomonas) solanacearum is a soil-borne phytopathogen that causes a wilting disease of many important crops. It makes large amounts of the exopolysaccharide EPS I, which it requires for efficient colonization, wilting, and killing of plants. Transcription of the eps operon, encoding biosynthetic enzymes fo... |
9573156 | Isolation and characterization of three Streptococcus pneumoniae transformation-specific loci by use of a lacZ reporter insertion vector. | Although more than a dozen new proteins are produced when Streptococcus pneumoniae cells become competent for genetic transformation, only a few of the corresponding genes have been identified to date. To find genes responsible for the production of competence-specific proteins, a random lacZ transcriptional fusion lib... |
9573146 | The periplasmic cyclodextrin binding protein CymE from Klebsiella oxytoca and its role in maltodextrin and cyclodextrin transport. | Klebsiella oxytoca M5a1 has the capacity to transport and to metabolize alpha-, beta- and gamma-cyclodextrins. Cyclodextrin transport is mediated by the products of the cymE, cymF, cymG, cymD, and cymA genes, which are functionally homologous to the malE, malF, malG, malK, and lamB gene products of Escherichia coli. Cy... |
9573050 | The ClpXP and ClpAP proteases degrade proteins with carboxy-terminal peptide tails added by the SsrA-tagging system. | Interruption of translation in Escherichia coli can lead to the addition of an 11-residue carboxy-terminal peptide tail to the nascent chain. This modification is mediated by SsrA RNA (also called 10Sa RNA and tmRNA) and marks the tagged polypeptide for proteolysis. Degradation in vivo of lambda repressor amino-termina... |
9571238 | Nuclear ferritin protects DNA from UV damage in corneal epithelial cells. | Previously, we identified the heavy chain of ferritin as a developmentally regulated nuclear protein of embryonic chicken corneal epithelial cells. The nuclear ferritin is assembled into a supramolecular form indistinguishable from the cytoplasmic form of ferritin found in other cell types and thus most likely has iron... |
9566981 | Bone matrix proteins: isolation and characterization of a novel cell-binding keratan sulfate proteoglycan (osteoadherin) from bovine bone. | A small cell-binding proteoglycan for which we propose the name osteoadherin was extracted from bovine bone with guanidine hydrochloride-containing EDTA. It was purified to homogeneity using a combination of ion-exchange chromatography, hydroxyapatite chromatography, and gel filtration. The Mof the proteoglycan was 85,... |
9566980 | Calcium determines the supramolecular organization of fibrillin-rich microfibrils. | Microfibrils are ubiquitous fibrillin-rich polymers that are thought to provide long-range elasticity to extracellular matrices, including the zonular filaments of mammalian eyes. X-ray diffraction of hydrated bovine zonular filaments demonstrated meridional diffraction peaks indexing on a fundamental axial periodicity... |
9573115 | Identification and characterization of heparin binding regions of the Fim2 subunit of Bordetella pertussis. | Bordetella pertussis fimbriae bind to sulfated sugars such as heparin through the major subunit Fim2. The Fim2 subunit contains two regions, designated H1 and H2, which show sequence similarity with heparin binding regions of fibronectin, and the role of these regions in heparin binding was investigated with maltose bi... |
9574693 | Gemella bergeriae sp. nov., isolated from human clinical specimens. | Six strains of a hitherto-undescribed gram-positive, catalase-negative, facultatively anaerobic coccus from human sources were characterized by phenotypic and molecular taxonomic methods. Comparative 16S rRNA gene sequencing studies demonstrated that the unknown strains are genealogically homogeneous and constitute a n... |
9574682 | Growth and survival of Helicobacter pylori in defined medium and susceptibility to Brij 78. | The gastrointestinal pathogen Helicobacter pylori requires supplementation with either fetal calf serum (FCS), bovine serum albumin (BSA), or (2,6-dimethyl)-beta-cyclodextrin (CD) for growth in a complex or defined medium. Because the availability of medium in which all components were chemically defined would facilita... |
9573179 | S-layered Aneurinibacillus and Bacillus spp. are susceptible to the lytic action of Pseudomonas aeruginosa membrane vesicles. | When S-layered strains of Bacillus stearothermophilus and Aneurinibacillus thermoaerophilus, possessing S-layers of different lattice type and lattice constant as well as S-(glyco)protein chemistry, and isogenic S-layerless variants were subjected to membrane vesicles (MVs) from P. aeruginosa during plaque assays on pl... |
9565404 | Self-inhibition in amiloride-sensitive sodium channels in taste receptor cells. | Electrophysiological recording techniques were used to study the Na+ dependence of currents through amiloride-sensitive sodium channels (ASSCs) in rat taste cells from the fungiform and vallate papillae. Perforated patch voltage clamp recordings were made from isolated fungiform and vallate taste receptor cells (TRCs) ... |
9563941 | An analysis of the origins of a cooperative binding energy of dimerization. | The cooperativity between binding of cell wall precursor analogs (ligands) to and antibiotic dimerization of the clinically important vancomycin group antibiotics was investigated by nuclear magnetic resonance. When dimerization was weak in the absence of a ligand, the increase in the dimerization constant in the prese... |
9562628 | An assay method for glycogen debranching enzyme using new fluorogenic substrates and its application to detection of the enzyme in mouse brain. | An assay method for glycogen debranching enzyme involving fluorogenic dextrins as substrates was developed. Two dextrins were prepared from 6-O-alpha-D-glucosyl-alpha-cyclodextrin and glucose by taking advantage of the action of Bacillus macerans cyclodextrin glucanotransferase, and converted by pyridylamination to flu... |
9560325 | cDNA sequence and heterologous expression of monomeric spinach pullulanase: multiple isomeric forms arise from the same polypeptide. | The spinach pullulanase gene was cloned and sequenced using peptide sequences of the purified enzyme as a starting point and employing PCR techniques and cDNA library screening. Its open reading frame codes for a protein of 964 amino acids which represents a precursor of the pullulanase. The N-terminal transit peptide ... |
9560324 | Protein heterogeneity of spinach pullulanase results from the coexistence of interconvertible isomeric forms of the monomeric enzyme. | Purified pullulanase (starch-debranching enzyme, R-enzyme, EC 3.2.1. 41) from spinach (Spinacia oleracea L.) chloroplasts separated into at least seven individual enzymically active proteins (isomers, numbered 1-7) on isoelectric focusing or column chromatofocusing. At their isoelectric points (between pH 4.7 and 5.2) ... |
9560306 | Thiol-independent interaction of protein disulphide isomerase with type X collagen during intra-cellular folding and assembly. | Protein disulphide isomerase (PDI) has been shown to be a multifunctional protein capable of catalysing disulphide-bond formation and isomerization, and of participating as a non-catalytic subunit of prolyl 4-hydroxylase (P4-H) and microsomal triacylglycerol transfer protein. It has also been proposed to function as a ... |
9566885 | Increased c-fos mRNA expression by human fibroblasts contracting stressed collagen matrices. | We studied early changes in gene expression during fibroblast contraction of stressed collagen matrices. The level of c-fos mRNA increased dramatically and peaked 50 to 60 min after matrix contraction was initiated. This response did not require serum and could not be accounted for simply by disruption of the actin cyt... |
9555094 | Novel vectors for gene delivery formed by self-assembly of DNA with poly(L-lysine) grafted with hydrophilic polymers. | Complexes formed between DNA and cationic polymers are attracting increasing attention as novel synthetic vectors for delivery of genes. We are trying to improve biological properties of such complexes by oriented self-assembly of DNA with cationic-hydrophilic block copolymers, designed to enshroud the complex within a... |
9559325 | Effect of hydroxypropyl-beta-cyclodextrin on the central stimulant activity of (-)-ephedrine and an oxazolidine prodrug in rats. | 1. Hydroxypropyl-beta-cyclodextrin (HP-beta-CD) increases the stability of the oxazolidine prodrug toward hydrolysis. 2. The binding constant (Kb) and rate constant (Kc) for the hydrolysis of the prodrug-HP-beta-CD complex were calculated from the kinetic data. 3. Ion-spray mass spectra confirmed prodrug-HP-beta-CD com... |
9557701 | Role of matrix in an early postentry step in the human immunodeficiency virus type 1 life cycle. | The matrix protein of human immunodeficiency virus type 1 (HIV-1) has been reported to play a crucial role in the targeting of the Gag polyprotein precursor to the plasma membrane and in the incorporation of viral envelope glycoproteins into budding virions. In this report, we present evidence that mutation of a highly... |
9547238 | Selective fasciculation and divergent pathfinding decisions of embryonic chick motor axons projecting to fast and slow muscle regions. | Proper motor function requires the precise matching of motoneuron and muscle fiber properties. The lack of distinguishing markers for early motoneurons has made it difficult to determine whether this matching is established by selective innervation during development or later via motoneuron-muscle fiber interactions. T... |
9538696 | Unusual behavior exhibited by multistranded guanine-rich DNA complexes. | The structural properties of oligonucleotides containing two different types of G-rich sequences at the 3'-ends were compared. It is shown that oligonucleotides with uninterrupted runs of guanine residues at the 3'-end, e.g., d(T15G12), form multistranded structures stabilized by guanine-guanine interactions. The chemi... |
29711479 | C<sub>60</sub> and C<sub>70</sub> Compounds in the Pincerlike Jaws of Calix[6]arene. | Isostructural species are found in the solid state for the supramolecular 1:2 complexes of a calix[6]arene molecule and either C<sub>60</sub> or C<sub>70</sub> (see the structure of the [(calix[6]arene)(C<sub>60</sub> )<sub>2</sub> ] complex on the right). The calixarene assumes a double-cone conformation, and the over... |
29711478 | Hemicarceplexes That Release Guests upon Irradiation. | Cleavage of one of the four bridging units in the two new types of hemicarceplexes presented here is sufficient to effect immediate guest release into the chloroform solvent (shown schematically on the right). The thermal stability and photoactivity of these hemicarceplexes indicate that incarceration is potentially us... |
29711475 | Ligand Self-Recognition in the Self-Assembly of a [{Cu(L)}<sub>2</sub> ]<sup>2+</sup> Complex: The Role of Chirality. | The chirality alone of a conformationally restricted, bifunctional ligand (L) is the basis for the self-recognition process schematically represented below. A racemic mixture of these ligands reacts with Cu<sup>+</sup> ions quantitatively to generate a racemic mixture of a [(CuL)<sub>2</sub> ]<sup>2+</sup> homochiral c... |
29711474 | Fullerenes Enclosed in Bridged Calix[5]arenes. | Host systems that bind C<sub>70</sub> preferentially to C<sub>60</sub> are found in the bridged calix[5]arenes 1 (X= alkyne bridge). The complexation-induced shifts of the bound fullerene guests provide valuable information on the structure and dynamics of the supramolecular complex. |
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