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7588597 | Structure of the binding site for inositol phosphates in a PH domain. | Phosphatidylinositol bisphosphate has been found to bind specifically to pleckstrin homology (PH) domains that are commonly present in signalling proteins but also found in cytoskeleton. We have studied the complexes of the beta-spectrin PH domain and soluble inositol phosphates using both circular dichroism and nuclea... |
7473715 | Purification of KorA protein from broad host range plasmid RK2: definition of a hierarchy of KorA operators. | The KorA protein of promiscuous plasmid RK2 is encoded in the central control operon, which coordinates expression of genes for replication, transfer and partitioning. KorA is known to repress transcription from seven promoters on the plasmid genome but at the trfA promoter, for the vegetative replication genes, it als... |
7585943 | Regulation of clathrin assembly and trimerization defined using recombinant triskelion hubs. | Clathrin polymerization into a polyhedral vesicle coat drives receptor sorting at cellular membranes during endocytosis and organelle biogenesis. To study clathrin self-assembly, we expressed the C-terminal third of the clathrin heavy chain in bacteria. The recombinant fragment trimerized, bound clathrin light chains, ... |
7559653 | The role of N-glycosylation for functional expression of the human platelet-activating factor receptor. Glycosylation is required for efficient membrane trafficking. | Streptococcus pneumoniae has been shown to utilize the platelet activating factor receptor for binding and invasion of host cells (Cundell, D. R., Gerard, N. P., Gerard, C., Idanpaan-Heikkila, I., and Tuomanen, E. I. (1995) Nature, in press). Because bacterial binding is in part carbohydrate dependent, and the human pl... |
7577941 | Comparison of lethal and nonlethal transthyretin variants and their relationship to amyloid disease. | The role that transthyretin (TTR) mutations play in the amyloid disease familial amyloid polyneuropathy (FAP) has been probed by comparing the biophysical properties of several TTR variants as a function of pH. We have previously demonstrated that the partial acid denaturation of TTR is sufficient to effect amyloid fib... |
7559784 | A chromatin binding site in the tail domain of nuclear lamins that interacts with core histones. | Interaction of chromatin with the nuclear envelope and lamina is thought to help determine higher order chromosome organization in the interphase nucleus. Previous studies have shown that nuclear lamins bind chromatin directly. Here we have localized a chromatin binding site to the carboxyl-terminal tail domains of bot... |
14732069 | A minimalist view of the secretory pathway in Plasmodium falciparum. | Would nature accept a eukaryotic cell that lacks a Golgi complex during a major part of its life cycle? Here, George Banting, Jürgen Benting and Klaus Lingelbach review recent morphological and biochemical data on the asexual intraerythrocytic stages of the protozoan parasite Plasmodium falciparum. They argue that thes... |
24226791 | Wavelength-selective fluorescence as a novel tool to study organization and dynamics in complex biological systems. | The dynamics exhibited by a given component of a large macromolecule such as a folded globular protein or an organized supramolecular assembly like the biological membrane is a function of its precise localization within the larger system. A set of approaches based on the red edge effect in fluorescence spectroscopy, w... |
24214430 | Electrospray ionization mass spectrometric study of encapsulation of amino acids by cyclodextrins. | Electrospray ionization (ESI) mass spectrometry has been used to study inclusion (host-guest) complexes of cyclodextrins (CDs) with amino acids. Host-guest complexes formed in solution are stable for characterization by ESI mass spectrometry: The relative abundances and the stoichiometry of the complexes formed in solu... |
18623437 | Domain E of Bacillus macerans cyclodextrin glucanotransferase: An independent starch-binding domain. | The starch-binding domains of glucoamylase I (SBD of GA-I) from Aspergillus awamori and of cyclodextrin glucanotransferase (domain E of CGTase) from Bacillus macerans were fused to the C-terminus of beta-galactosidase (beta-gal) The majority of the fusion proteins produced in Escherichia coli were found as inclusion bo... |
7575431 | Kinetic and spectroscopic studies on a superoxide dismutase from Propionibacterium shermanii that is active with iron or manganese: pH-dependence. | Kinetic studies were performed on the superoxide dismutases isolated from the anaerobic bacterium Propionibacterium shermanii as active enzymes with either iron or manganese, which were naturally incorporated into the same molecule depending on the metal supply. Both the Fe- and Mn- forms showed decreasing activity wit... |
7575427 | Molecular cloning and deduced amino acid sequences of the alpha- and beta- subunits of mammalian NAD(+)-isocitrate dehydrogenase. | A 153 bp fragment of the cDNA encoding the beta-subunit of pig heart NAD(+)-isocitrate dehydrogenase (NAD(+)-ICDH) was specifically amplified by PCR, using redundant oligonucleotide primers based on partial peptide sequence data [Huang and Colman (1990) Biochemistry 29, 8266-8273]. This PCR fragment was then used as a ... |
8530844 | [Double valve replacement with mechanical prostheses--an operative results]. | From January 1980 to December 1993, sixty eight patients underwent double valve replacement with mechanical prostheses. There were forty males and twenty-eight females with a mean age of 49.6 years (ranging from 30 to 68 years). They were classified 10 of NYHA class IV, 28 of class III. Twelve patients had previous car... |
7561776 | Human enteric Caliciviridae: the complete genome sequence and expression of virus-like particles from a genetic group II small round structured virus. | Comparisons of the RNA polymerase and capsid sequences of small round structured viruses (SRSVs) have recently shown these are genetically diverse viruses which fall into two distinct groups. The genomes of two group I viruses, Southampton and Norwalk viruses have been characterized; however, similar data for the genet... |
7563055 | Thermodynamic mapping of the inhibitor site of the aspartic protease endothiapepsin. | The discovery that the protease from the human immunodeficiency virus (HIV) belongs to the aspartic protease family has generated renewed interest in this class of proteins. In this paper, the interactions of endothiapepsin, an aspartic proteinase from the fungus Endothia parasitica, with the inhibitor pepstatin A have... |
7585717 | Separation of cyclodextrins and their derivatives by thin-layer and preparative column chromatography. | Cyclodextrins, their derivatives and products of their partial hydrolysis are clearly separated by chromatography on silica gel by mobile phases containing aqueous ammonia and organic solvent (acetonitrile or 1-propanol). This system allows separation of compounds with different numbers of substituents on cyclodextrin,... |
7553685 | Immunotherapy of human colon cancer by antibody-targeted superantigens. | T lymphocytes generally fail to recognize human colon carcinomas, suggesting that the tumour is beyond reach of immunotherapy. Bacterial superantigens are the most potent known activators of human T lymphocytes and induce T cell cytotoxicity and cytokine production. In order to develop a T-cell-based therapy for colon ... |
7548164 | Comparison of primary structures and substrate specificities of two pullulan-hydrolyzing alpha-amylases, TVA I and TVA II, from Thermoactinomyces vulgaris R-47. | Thermoactinomyces vulgaris R-47 produces two alpha-amylases, TVA I, an extracellular enzyme, and TVA II, an intracellular enzyme. Both enzymes hydrolyze pullulan to produce panose, and also hydrolyze cyclodextrins. We cloned and sequenced the TVA I gene. The TVA I gene consisted of 1833 base pairs, and the deduced prim... |
7677193 | Differential expression of galectin-1 and galectin-3 in thyroid tumors. Potential diagnostic implications. | Carcinoma of the thyroid gland, the most frequently diagnosed endocrine malignancy, is often associated with early regional metastases. With the exception of papillary carcinoma, distinguishing benign from malignant thyroid neoplasms in the absence of metastatic disease is difficult. Recently, the vertebrate lectins ga... |
7673242 | Electrophoresis of chromatin on nondenaturing agarose gels containing Mg2+. Self-assembly of small chromatin fragments and folding of the 30-nm fiber. | We show that nondenaturing agarose gels can be used for the study of the structure and dynamic properties of native (uncross-linked) chromatin. In gels containing 1.7 mM Mg2+, chicken erythrocyte chromatin fragments having from about 6 to 50 nucleosomes produce well defined bands. These bands have an electrophoretic mo... |
7669918 | Core directed self-assemblies in the solid state of retro Aib bis-peptide dicarboxylic acids; a design strategy for control of molecular orientation in peptides. | Self-assembly patterns as a function of the central core insert in the retro bis-peptide dicarboxylic acids HO-Aib-X-Aib-OH, containing oxalyl (-CO-CO-; 1), fumaryl (-CO-CH = CH-CO-; 2), and adipoyl [-CO-(CH2)4-CO-; 3], have been characterized by single crystal x-ray diffraction analyses. Extensive hydrogen bonding occ... |
7545169 | P-glycoprotein. Associations between domains and between domains and molecular chaperones. | P-glycoprotein consists of two homologous halves, each composed of a transmembrane domain and a nucleotide-binding domain. In order to understand how the domains interact in P-glycoprotein, we expressed each domain as a separate polypeptide and tested for associations using coimmunoprecipitation assays. We found that t... |
7665533 | Pyridine carboxylic acids as inhibitors and substrates of the Escherichia coli gab permease encoded by gabP. | Although considered selective for its natural substrate, 4-aminobutyrate, gab permease was inhibited by 1,2,3,6-tetrahydro-3-pyridinecarboxylate and 1,2,3,6-tetrahydro-4-pyridinecarboxylate. The former is a transported substrate, since its preloading into metabolically poisoned cells stimulated transient accumulation o... |
7665522 | Unique cholesteryl glucosides in Helicobacter pylori: composition and structural analysis. | A chloroform-methanol-extracted lipid of Helicobacter pylori was studied. Three kinds of glycolipids, accounting for about 25% (wt/wt) of the total lipid, were detected and identified to be cholesteryl glucosides. The structures of two of them were determined to be cholesteryl-alpha-D-glucopyranoside and cholesteryl-6-... |
7665509 | Cloning and analysis of structural genes from Streptomyces pristinaespiralis encoding enzymes involved in the conversion of pristinamycin IIB to pristinamycin IIA (PIIA): PIIA synthase and NADH:riboflavin 5'-phosphate oxidoreductase. | In Streptomyces pristinaespiralis, two enzymes are necessary for conversion of pristinamycin IIB (PIIB) to pristinamycin IIA (PIIA), the major component of pristinamycin (D. Thibaut, N. Ratet, D. Bisch, D. Faucher, L. Debussche, and F. Blanche, J. Bacteriol. 177:5199-5205, 1995); these enzymes are PIIA synthase, a hete... |
7665471 | Structure of peptidoglycan from Thermus thermophilus HB8. | The composition and structure of peptidoglycan (murein) extracted from the extreme thermophilic eubacterium Thermus thermophilus HB8 are presented. The structure of 29 muropeptides, accounting for more than 85% of total murein, is reported. The basic monomeric subunit consists of N-acetylglucosamine-N-acetylmuramic aci... |
7665463 | A consensus sequence for binding of Lrp to DNA. | Lrp (leucine-responsive regulatory protein) is a major regulatory protein involved in the expression of numerous operons in Escherichia coli. For ilvIH, one of the operons positively regulated by Lrp, Lrp binds to multiple sites upstream of the transcriptional start site and activates transcription. An alignment of 12 ... |
9383462 | Polyketide synthesis in vitro on a modular polyketide synthase. | <h4>Background</h4>The 6-deoxyerythronolide B synthase (DEBS) of Saccharopolyspora erythraea, which synthesizes the aglycone core of the antibiotic erythromycin A, contains some 30 active sites distributed between three multienzyme polypeptides (designated DEBS1-3). This complexity has hitherto frustrated mechanistic a... |
9384781 | Capillary electrophoresis enantioseparation of noncharged and anionic chiral compounds using anionic cyclodextrin derivatives as chiral selectors. | The electrophoretic profiles of anionic cyclodextrin derivatives were studied in benzoic acid and phosphate buffers. All anionic derivatives studied exhibited a multicomponent profile. The mobilities of beta-cyclodextrin (beta-CD) sulfates do not depend substantially on the pH. Carboxymethyl ether of beta-cyclodextrin ... |
9384778 | Direct chiral resolution of tiaprofenic acid in pharmaceutical formulations by capillary zone electrophoresis using cyclodextrins as chiral selector. | Capillary zone electrophoresis (CZE) was used for the enantiomeric separation of (R,S)-tiaprofenic acid ([R,S]-Tia) in a pharmaceutical formulation employing an acetate buffer at pH 4.5 and 2,3,6-tri-O-methyl-beta-cyclodextrin (tri-OMe-beta-CD) as the chiral selector. The effect of the concentration of trimethylated-be... |
8619952 | Conservation of water molecules in an antibody-antigen interaction. | The solvation of the antibody-antigen Fv D1.3-lysozyme complex is investigated through a study of the conservation of water molecules in crystal structures of the wild-type Fv fragment of antibody D1.3, 5 free lysozyme, the wild-type Fv D1.3-lysozyme complex, 5 Fv D1.3 mutants complexed with lysozyme and the crystal st... |
8619951 | Blocking of CD4 cell receptors for the human immunodeficiency virus type 1 (HIV-1) by chemically modified bovine milk proteins: potential for AIDS prophylaxis. | The chemical transformation of synthetic combinatorial libraries to increase the diversity of compounds of medicinal interest was reported recently. Chemical modification of natural products represents a complementary approach to accomplish this aim. Modification of lysines by aromatic acid anhydrides, preferentially b... |
8619950 | Searching for pharmacophoric patterns in databases of three-dimensional chemical structures. | This paper provides an overview of the research that has been carried out in Sheffield over the last decade into searching techniques for databases of three-dimensional (3D) chemical structures. A 3D structure or query pattern is represented by a labelled graph, in which the nodes and the edges of the graph are used to... |
8619949 | S1 nuclease: immunoaffinity purification and evidence for the proximity of cysteine 25 to the substrate binding site. | A simple procedure, involving heat treatment, gel filtration on Sephadex-G 100 followed by chromatography on anti-S1 nuclease antibodies bound to Sepharose, was developed for purification of S1 nuclease to homogeneity with an overall yield of 72%. S1 nuclease was rapidly inactivated, at pH 6.0 and 37 degrees C, in pres... |
8570709 | Octa-alkyl zinc phthalocyanines: potential photosensitizers for use in the photodynamic therapy of cancer. | The synthesis, characterization and electronic spectra of a series of nine 1,4,8,11,15,18,22,25-octa-alkyl zinc phthalocyanines (ZnPc), potential photosensitizers for the photodynamic therapy of cancer, are described. The substituents on the phthalocyanine (Pc) macrocycle "red-shift" the absorbance maximum, in cyclohex... |
8581044 | [The effect of inhibitors of sodium permeability (novocaine and tetrodotoxin) on the trace depolarization of myelinated nerve fibers]. | Partial block of the sodium permeability by local anesthetics does not induce significant aftereffect of depolarisation in intact Ranvier nodes of the frog isolated myelinated nerve fibres. The sodium current seems to take no part in generation of the depolarisation aftereffect. |
8572599 | Evaluation of in vitro cytotoxicity of carboranyl amino acids, their chemical precursors and nido carboranyl amino acids for boron neutron capture therapy. | The purpose of the present study was to define the in vitro cellular toxicity of three carborane-containing amino acids: p-(o-carboran-yl)-phenylalanine (CBPA), O-(o-carboran-1-ylmethyl)-tyrosine (CBT), and o-carboranylalanine (CBA), which are analogues of phenylalanine, tyrosine, and alanine respectively. In addition,... |
8572598 | In vitro and in vivo evaluation of o-carboranylalanine as a potential boron delivery agent for neutron capture therapy. | o-Carboranylalanine (B10H10C2CH2CHNH2COOH) is a carborane-containing amino acid, which has been synthesized as a potential capture agent for boron neutron capture therapy (BNCT) of cancer. The purpose of the present study was to develop a rational approach for the in vitro and in vivo evaluation of boron containing com... |
8544084 | Efficacy of oral saperconazole in systemic murine aspergillosis. | Saperconazole is a fluorinated bis-triazole. Groups of ten 5-week-old female CD-1 mice were infected intravenously with 5.5 x 10(7) Aspergillus conidia. Saperconazole, dissolved in hydroxypropyl-beta-cyclodextrin (HPBC), was given orally twice a day for 11 days, beginning 1 day post-infection, at 50, 100 or 200 mg kg-1... |
8585086 | Cloning and characterization of the cDNAs encoding Na+ channel-specific toxins 1 and 2 of the scorpion Centruroides noxius Hoffmann. | Using a cDNA library prepared from venomous glands of the Mexican scorpion Centruroides noxius Hoffmann the genes that encode toxins 1 and 2 were identified, cloned and sequenced. In view of the proposed mechanism for processing the mature peptides coded by these two genes, the corresponding peptide-toxins were sequenc... |
8578804 | The use of synthetic peptides can be a misleading approach to generate vaccines against scorpion toxins. | Seven peptides corresponding to the amino acid sequence of toxin 2 from the scorpion Centruroides noxius were chemically synthesized, purified and assayed in mice for their putative neutralizing properties against scorpion toxins. All the peptides were immunogenic and some produced neutralizing antibodies, as verified ... |
8570537 | Hydroxypropyl-beta-cyclodextrin increases the aqueous solubility and stability of pilocarpine prodrugs. | <h4>Purpose</h4>The effects of 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CD) on the aqueous solubility and stability of two lipophilic bispilocarpine prodrugs were investigated at pH 7.4.<h4>Methods</h4>The solubility of prodrugs was studied by phase-solubility method (0-72.5 mM HP-beta-CD). The stability of one of th... |
8570530 | Drug delivery studies in Caco-2 monolayers. IV. Absorption enhancer effects of cyclodextrins. | <h4>Purpose</h4>The purpose of the present study was to use the human colorectal carcinoma cell line. Caco-2, as a human intestinal epithelial model for studying the effects of cyclodextrins as absorption enhancers.<h4>Methods</h4>Cyclodextrins of varying sizes and physicochemical characters were investigated. The effe... |
8573280 | Amylolytic enzymes and products derived from starch: a review. | This review provides current information on starch and its molecular composition, common and potential sources, and manufacturing processes. It also deals with the five groups of enzymes involved in the hydrolysis of starch: the endo- and exoamylases, which act primarily on the alpha-1,4 linkages; the debranching enzym... |
8619310 | Ribosomal frameshifting in yeast viruses. | Proper maintenance of translational reading frame by ribosomes is essential for cell growth and viability. In the last 10 years it has been shown that a number of viruses induce ribosomes to shift reading frame in order to regulate the expression of gene products having enzymatic functions. Studies on ribosomal framesh... |
8564412 | The polypeptide 3(10)-helix as a template for molecular recognition studies. Structural characterization of a side-chain functionalized octapeptide. | A N alpha-blocked, Aib-rich octapeptide methylamide containing two N omega-benzoylated L-Lys residues at positions 3 and 6 was synthesized by solution methods and fully characterized. A solution and crystal-state conformational analysis, performed by using FT-IR, 1H NMR, CD, and X-ray diffraction techniques, showed tha... |
8528088 | Influence of divalent cations in protein crystallization. | We have tested the effect of several cations in attempts to crystallize the ligand-bound forms of the leucine/isoleucine/valine-binding protein (LIVBP) (M(r) = 36,700) and leucine-specific binding protein (LBP) (M(r) = 37,000), which act as initial periplasmic receptors for the high-affinity osmotic-shock-sensitive act... |
8529418 | Ophthalmic arachidonylethanolamide decreases intraocular pressure in normotensive rabbits. | Arachidonylethanolamide (AEA) was the first anandamide to be identified as an endogenous ligand for the cannabinoid receptor of porcine brain. Since cannabinoids have shown some value in the reduction of ocular hypertension, the title compound was evaluated in normotensive rabbits as a possible topically applied agent ... |
7503421 | Biosynthetic preparation of isotopically labeled heme. | An efficient method for the preparation of isotopically enriched heme has been developed. This method utilizes a commercially available bacterial host and plasmid, into which a synthetic gene encoding for rat liver outer mitochondrial membrane cytochrome b5, a heme-binding protein, has been inserted. The method describ... |
7498094 | Comparisons of estimated human body burdens of dioxinlike chemicals and TCDD body burdens in experimentally exposed animals. | Humans are exposed to mixtures of polyhalogenated aromatic hydrocarbons, and the potential health effects of these exposures are uncertain. A subset of this class of compounds produce similar spectra of toxicity in experimental animals as does 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and these chemicals have been cl... |
8534917 | Vinblastine suppresses dynamics of individual microtubules in living interphase cells. | We have characterized the effects of vinblastine on the dynamic instability behavior of individual microtubules in living BS-C-1 cells microinjected with rhodamine-labeled tubulin and have found that at low concentrations (3-64 nM), vinblastine potently suppresses dynamic instability without causing net microtubule dep... |
8537886 | A new pH-metric methodology for the determination of thermodynamic inclusion constants of guest/cyclodextrin complexes. | A new methodology of pH-metric data treatment was developed to extract the stoichiometry and the thermodynamic association constants of guest-cyclodextrin inclusion complexes in dilute aqueous solution when the guest is a participant in an acid-base equilibrium. pH-metric titration curves in the presence of cyclodextri... |
7474577 | [Analysis of tracheostomy for patients after thoracic esophageal cancer resection]. | Tracheostomy is an available method for respiratory management, but a consensus has not been reached with regard to the significance of postoperative respiratory management. So, we analyzed postoperative tracheostomy patients of esophageal cancer and clarified its significance. We analyzed 26 patients from among 85 who... |
8527291 | Dose proportional pharmacokinetics of alprostadil (prostaglandin E1) in healthy volunteers following intravenous infusion. | Prostaglandin E1 (PGE1) (30, 60, 120 micrograms) was administered by intravenous infusion over a 120 min period in an open, three way randomized, cross-over study to 12 healthy male volunteers. For the evaluation of PGE1, PGE0 and 15-keto-PGE0, blood samples were drawn prior to, during and after the infusion. Analytica... |
7495558 | Using oligonucleotide probe arrays to access genetic diversity. | As the Human Genome Project and related efforts identify and determine the DNA sequences of human genes, it is important that highly reliable and efficient mechanisms are found to access individual genetic variation. It is only through a greater understanding of genetic diversity that the true benefit of the Human Geno... |
7575987 | DNA alkylation by minor groove-binding N1-alkoxyalkyl-bis-benzimidazoles. | Two groups of isomeric N1-alkoxyalkyl-bis-benzimidazoles differing in the orientation of the N-alkoxyalkyl group (R) with respect to the DNA minor groove have been examined as to their reaction with DNA. Agarose gel mobility shift assay demonstrates that the 'R-inward' isomers alkylate and cause thermally induced stran... |
7484264 | [Severe poisoning by organophosphate compounds. An analysis of mortality and of the value of serum cholinesterase in monitoring the clinical course]. | Ingestion of organophosphate (OP) compounds usually results in severe poisoning. We undertook a retrospective study of 52 consecutive patients admitted with severe OP poisoning to determine the value of serum cholinesterase (SChE) in monitoring clinical course. Considering survivors and non-survivors, we evaluate clini... |
7495475 | Evaluation of polysaccharides intended for ophthalmic use in ocular dosage forms. | Different water-soluble polysaccharides were evaluated for their intended use in ocular dosage forms. The physicochemical characteristics and the viscosity of the solutions prepared with several iso-osmotic vehicles were measured. The influence of ions present in lacrimal fluid, mucin and cyclodextrin on the rheologica... |
8519963 | Femtosecond probe of structural analogies between chlorosomes and bacteriochlorophyll c aggregates. | Bacteriochlorophyll c pigments extracted from light harvesting chlorosomes in green photosynthetic bacteria are known to self-assemble into aggregates whose electronic spectroscopy resembles that of intact chlorosomes. Femtosecond optical experiments reveal that the chlorosomes and their reconstituted aggregates exhibi... |
8519962 | Direct observation of sub-picosecond equilibration of excitation energy in the light-harvesting antenna of Rhodospirillum rubrum. | Excitation energy transfer in the light-harvesting antenna of Rhodospirillum rubrum was studied at room temperature using sub-picosecond transient absorption measurements. Upon excitation of Rs. rubrum membranes with a 200 fs, 600 nm laser flash in the Qx transition of the bacteriochlorophyll-a (BChl-a) absorption, the... |
8519958 | Analysis of the structure of dimeric DNA catenanes by electron microscopy. | We analyzed the structure of open-circular and supercoiled dimeric DNA catenanes generated by site-specific recombination in vitro. Electron microscopy of open-circular catenanes shows that the number of duplex crossings in a plane is a linear function of the number of catenane interlinks (Ca/2), and that the length of... |
8519992 | The hemifusion intermediate and its conversion to complete fusion: regulation by membrane composition. | To fuse, membranes must bend. The energy of each lipid monolayer with respect to bending is minimized at the spontaneous curvature of the monolayer. Two lipids known to promote opposite spontaneous curvatures, lysophosphatidylcholine and arachidonic acid, were added to different sides of planar phospholipid membranes. ... |
8519980 | Kinetics of microtubule catastrophe assessed by probabilistic analysis. | Microtubules are cytoskeletal filaments whose self-assembly occurs by abrupt switching between states of roughly constant growth and shrinkage, a process known as dynamic instability. Understanding the mechanism of dynamic instability offers potential for controlling microtubule-dependent cellular processes such as ner... |
8536994 | 5 S rRNA is involved in fidelity of translational reading frame. | Chromosomal mutants (maintenance of frame = mof) in which the efficiency of -1 ribosomal frameshifting is increased can be isolated using constructs in which lacZ expression is dependent upon a -1 shift of reading frame. We isolate a new mof mutation, mof9, in Saccharomyces cerevisiae and show that it is complemented b... |
7565413 | mRNA stability in mammalian cells. | This review concerns how cytoplasmic mRNA half-lives are regulated and how mRNA decay rates influence gene expression. mRNA stability influences gene expression in virtually all organisms, from bacteria to mammals, and the abundance of a particular mRNA can fluctuate manyfold following a change in the mRNA half-life, w... |
7565410 | Molecular basis of cell integrity and morphogenesis in Saccharomyces cerevisiae. | In fungi and many other organisms, a thick outer cell wall is responsible for determining the shape of the cell and for maintaining its integrity. The budding yeast Saccharomyces cerevisiae has been a useful model organism for the study of cell wall synthesis, and over the past few decades, many aspects of the composit... |
7565409 | Protein trafficking in kinetoplastid protozoa. | The kinetoplastid protozoa infect hosts ranging from invertebrates to plants and mammals, causing diseases of medical and economic importance. They are the earliest-branching organisms in eucaryotic evolution to have either mitochondria or peroxisome-like microbodies. Investigation of their protein trafficking enables ... |
7574649 | New polymeric model substrates for the study of microbial ligninolysis. | Lignin model dimers are valuable tools for the elucidation of microbial ligninolytic mechanisms, but their low molecular weight (MW) makes them susceptible to nonligninolytic intracellular metabolism. To address this problem, we prepared lignin models in which unlabeled and alpha-14C-labeled beta-O-4-linked dimers were... |
7559451 | Acid-facilitated supramolecular assembly of G-quadruplexes in d(CGG)4. | Molar [K+] induces aggregate formation in d(CGG)4, as evidenced by absorbance, circular dichroic (CD), and gel measurements. The kinetics of this transformation are extremely slow at pH 8 but are found to be greatly facilitated in acidic conditions. Kinetic profiles via absorbance or CD monitoring at single wavelength ... |
7548174 | Fermentable carbohydrates exert a more potent cholesterol-lowering effect than cholestyramine. | The purpose of this work was to assess the respective role of bile acid excretion and of the end-products of cecal fermentations in the cholesterol-lowering effect of complex carbohydrates. The effects of two different fermentable carbohydrates (guar gum, beta-cyclodextrin), and sequestrant resin (cholestyramine) have ... |
7563060 | DNA cleavage at two recognition sites by the SfiI restriction endonuclease: salt dependence of cis and trans interactions between distant DNA sites. | At low ionic strength, the SfiI restriction enzyme cleaved at similar rates both supercoiled and linear DNA with two SfiI sites and linear DNA with one SfiI site. For the substrates with two sites, the majority of the DNA was converted directly to products cut at both sites; the enzyme appears to bind to two sites befo... |
7551555 | In situ quantification of hsp70 and alpha-beta transcripts at 87A and 87C loci in relation to hsr-omega gene activity in polytene cells of Drosophila melanogaster. | The hsp70-coding duplicate loci at the 87A and 87C sites (the 87C site also carries heat-inducible alpha-beta repeats) in polytene nuclei are known to puff to different levels under conditions in which heat shock does not induce the non-protein-coding hsr-omega gene at the 93D site. To understand the basis of this uneq... |
7551554 | Restriction endonuclease/nick translation procedure on fixed chromosomes of the Atlantic salmon fish cell line. | We have used a restriction endonuclease/nick translation (RE/NT) procedure to study the ability of restriction enzymes to cleave DNA in fixed chromosomes of a fish cell line. This technique has proved to be very useful in revealing the chromatin heterogeneity underlying the chromosome structure that remains cryptic to ... |
7551553 | Direction of DNA sequences within chromatids determined using strand-specific FISH. | The 5' to 3' direction of DNA strands within chromatids of metaphase chromosomes can be determined by using simultaneous hybridization of a single strand of the telomere probe and a single strand of a repetitive sequence to slides pretreated for strand-specific hybridization. The telomere probe identifies the direction... |
7551552 | Imaging of DNA in human and plant chromosomes by high-resolution scanning electron microscopy. | We describe a DNA-specific staining procedure, using a blue platinum organic dye, which allows DNA imaging of chromosomes by detection of back-scattered electrons in the scanning electron microscope. DNA distribution is visualized within chromosomal details of the centromeric and satellite regions, or in interphase chr... |
7551551 | Molecular analysis of chromosomal polymorphism in the South American cricetid, Graomys griseoflavus. | Graomys griseoflavus is a South American phyllotine rodent widespread in Argentina that shows a high frequency of Robertsonian fusions (RFs). DNA restriction with EcoRI produced a 250-bp repeated family (EG250) specific for the genus. Southern hybridization and sequencing analysis indicate that the EG250 family is hete... |
7551550 | Mapping functional domains of the polycomb protein of Drosophila melanogaster. | In Drosophila the Polycomb group (Pc-G) proteins are responsible for the stable and heritable silencing of genes. The Pc-G apparently uses heterochromatin-like mechanisms to transcriptionally inactivate developmental regulators such as the homeotic genes. The Polycomb (Pc) protein is part of a large multimeric complex ... |
7551549 | Chromosomal location of endogenous geminivirus-related DNA sequences in Nicotiana tabacum L. | The N. tabacum (tobacco) nuclear genome carries approximately 25 multiple direct repeats of a geminivirus-related DNA (GRD) sequence that probably arose by illegitimate recombination, following geminivirus infection, during Nicotiana evolution. Each GRD repeat carries sequences similar to the geminiviral AL1 gene of th... |
7551548 | Analysis and chromosomal localization of retrotransposons in sugar beet (Beta vulgaris L.): LINEs and Ty1-copia-like elements as major components of the genome. | DNA sequences of the reverse transcriptase gene of long terminal repeat (LTR) and non-LTR (non-viral) retrotransposons have been isolated and cloned from the genome of sugar beet (Beta vulgaris). Both retrotransposon types are highly amplified in sugar beet and may account for 2-5% of the genome. The BNR1 family, repre... |
7473901 | Early neutrophil sequestration after injury: a pathogenic mechanism for multiple organ failure. | Polymorphonuclear neutrophils (PMNs) play a pivotal role in the inflammation that precedes multiple organ failure (MOF). In a rat model of MOF, PMNs become primed for enhanced superoxide anion (O2-) release and CD11b expression, sequester in end organs, and produce organ failure. Therefore, we hypothesized that circula... |
7568141 | Identification of the overtone of the Fe-CO stretching mode in heme proteins: a probe of the heme active site. | Two CO-isotope sensitive lines have been detected in the overtone region of the resonance Raman spectra of CO-bound hemeproteins. One line is assigned as the overtone of the Fe-CO stretching mode and is located in the 1000- to 1070-cm-1 region. The other line is found in the 1180- to 1210-cm-1 region and is assigned as... |
7568102 | Lattice model for rapidly folding protein-like heteropolymers. | Protein folding is a relatively fast process considering the astronomical number of conformations in which a protein could find itself. Within the framework of a lattice model, we show that one can design rapidly folding sequences by assigning the strongest attractive couplings to the contacts present in a target nativ... |
7568084 | Redirecting the specificity of ubiquitination by modifying ubiquitin-conjugating enzymes. | Depletion of specific cellular proteins is a powerful tool in biological research and has many medical and agricultural benefits. In contrast to genetic methods currently available to attenuate protein levels, we describe an alternative approach that redirects the ubiquitin-dependent proteolytic pathway to facilitate s... |
7568063 | Molecular organization of histidine-tagged biomolecules at self-assembled lipid interfaces using a novel class of chelator lipids. | In molecular biology, the expression of fusion proteins is a very useful and well-established technique for the identification and one-step purification of gene products. Even a short fused sequence of five or six histidines enables proteins to bind to an immobilized metal ion chelate complex. By synthesis of a class o... |
7581849 | Combined polymerized chiral micelle and gamma-cyclodextrin for chiral separation in capillary electrophoresis. | A combination of a polymerized chiral micelle, poly(sodium N-undecylenyl-D-valinate) [poly(D-SUV)] and gamma-cyclodextrin (gamma-CD) is used for the first time for chiral separation in capillary electrophoresis. A simple theory is presented to rationalize the synergistic effect of the enantioselectivity obtained by use... |
7661114 | Muscle thickness, measured with ultrasound, may be an indicator of lean tissue wasting in multiple organ failure in the presence of edema. | Multiple organ failure (MOF) is accompanied by muscle wasting, but changes in body composition are frequently obscured by fluid retention (edema), mainly in superficial and visceral tissue. There is a need to assess body composition and changes in body composition in these circumstances independently of edema. A relati... |
7660123 | Direct evaluation of electronic coupling mediated by hydrogen bonds: implications for biological electron transfer. | Three supramolecular bischromophoric systems featuring zinc(II) and iron(III) porphyrins have been synthesized to evaluate the relative magnitudes of electronic coupling provided by hydrogen, sigma, and pi bonds. Laser flash excitation generates the highly reducing singlet excited state of the (porphinato)zinc chromoph... |
7658436 | Novel acridine-triazenes as prototype combilexins: synthesis, DNA binding, and biological activity. | A series of bifunctional ligands has been developed as prototype DNA-binding combilexins using a DNA template-directed approach. These novel agents contain a 1,3-diaryltriazene linker moiety, present in the established DNA minor groove-binder berenil [1,3-bis(4'-amidinophenyl)-triazene], which is attached to an interca... |
7544809 | Hepatitis B virus (HBV) sequence variation of cytotoxic T lymphocyte epitopes is not common in patients with chronic HBV infection. | It has been suggested that immune selection pressure exerted by the cytotoxic T lymphocyte (CTL) response could be responsible for viral persistence during chronic hepatitis B virus infection. To address this question, in the current study we compared the DNA and amino acid sequences of, and the CTL responses to, multi... |
7657696 | Crystal structure and subunit dynamics of the abalone sperm lysin dimer: egg envelopes dissociate dimers, the monomer is the active species. | Lysin is a 16-kD acrosomal protein used by abalone spermatozoa to create a hole in the egg vitelline envelope (VE) by a nonenzymatic mechanism. The crystal structure of the lysin monomer is known at 1.9 A resolution. The surface of the molecule reveals two tracks of basic residues running the length of one surface of t... |
7651423 | Genetic identification of the site of DNA contact in the yeast heat shock transcription factor. | The heat shock transcription factor (HSF), a trimeric transcription factor, activates the expression of heat shock genes in eukaryotes. We have isolated mutations in the HSF1 gene from Saccharomyces cerevisiae that severely compromise the ability of HSF to bind to its normal binding site, repeats of the module nGAAn. O... |
7651405 | Virus-mediated expression of firefly luciferase in the parasitic protozoan Giardia lamblia. | Giardia lamblia, a prevalent human pathogen and one of the lineages that branched earliest from prokaryotes, can be infected with a double-stranded RNA virus, giardiavirus (GLV). The 6,277-bp viral genome has been previously cloned (A.L. Wang, H.-M. Yang, K.A. Shen, and C.C. Wang, Proc. Natl. Acad. Sci. USA 90:8595-859... |
7650479 | Staphylococcal enterotoxin A has two cooperative binding sites on major histocompatibility complex class II. | The superantigen staphylococcal enterotoxin A (SEA) binds to major histocompatibility complex (MHC) class II molecules at two sites on either side of the peptide groove. Two separate but cooperative interactions to the human class II molecule HLA-DR1 were detected. The first high affinity interaction to the DR1 beta ch... |
7637026 | Two independent pathways of expression lead to self-assembly of the rabbit hemorrhagic disease virus capsid protein. | The rabbit hemorrhagic disease virus capsid protein was expressed in insect cells either as an individual protein species, from a mRNA analogous to the viral subgenomic RNA, or as part of a polyprotein that included the viral 3C-like protease and the RNA polymerase. Both pathways of expression led to the assembly of vi... |
7637011 | BHK cell proteins that bind to the 3' stem-loop structure of the West Nile virus genome RNA. | The first 83 3' nucleotides of the genome RNA of the flavivirus West Nile encephalitis virus (WNV) form a stable stem-loop (SL) structure which is followed in the genome by a smaller SL. These 3' structures are highly conserved among divergent flaviviruses, suggesting that they may function as cis-acting signals for RN... |
7636981 | Transcriptional enhancer activity of hr5 requires dual-palindrome half sites that mediate binding of a dimeric form of the baculovirus transregulator IE1. | The hr5 enhancer element stimulates early viral transcription and may function as an origin of DNA replication for Autographa californica nuclear polyhedrosis virus (AcMNPV). The smallest functional unit of hr5 is a 28-bp repeat consisting of an imperfect palindrome (28-mer). To identify essential sequences and examine... |
7543581 | Mimicry of the immunodominant conformation-dependent antigenic site of hepatitis A virus by motifs selected from synthetic peptide libraries. | Hepatitis A virus (HAV) is a positive-strand RNA virus with a genome length of approximately 7,480 nucleotides. Although HAV morphogenesis is thought to be similar to that of poliovirus, the prototype picornavirus, the complete characterization of the antigenic structure of this virus remains elusive. All the available... |
7636964 | In vitro selection and characterization of human immunodeficiency virus type 1 (HIV-1) isolates with reduced sensitivity to hydroxyethylamino sulfonamide inhibitors of HIV-1 aspartyl protease. | Human immunodeficiency virus type 1 (HIV-1) variants with reduced sensitivity to the hydroxyethylamino sulfonamide protease inhibitors VB-11,328 and VX-478 have been selected in vitro by two independent serial passage protocols with HIV-1 in CEM-SS and MT-4 cell lines. Virus populations with greater than 100-fold-incre... |
17758810 | Two-dimensional imaging of potential waves in electrochemical systems by surface plasmon microscopy. | The potential dependence of resonance conditions for the excitation of surface plasmons was exploited to obtain two-dimensional images of the potential distribution of an electrode with high temporal resolution. This method allows the study of spatiotemporal patterns in electrochemical systems. Potential waves travelin... |
16535108 | Purification and Characterization of a Maltotetraose-Forming Alkaline (alpha)-Amylase from an Alkalophilic Bacillus Strain, GM8901. | An alkalophilic bacterium, Bacillus sp. strain GM8901, grown at pH 10.5 and 50(deg)C, produced five alkaline amylases in culture broth. At an early stage of the bacterial growth, amylase I (Amyl I) was produced initially and then, as cultivation progressed, four alkaline amylases, Amyl II, Amyl III, Amyl IV, and Amyl V... |
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