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15825294 | [Cyclodextrin induced-room temperature phosphorescence for the determination of quinoline without deoxidization]. | A cyclodextrininduced-room temperature phosphorescence (CD-RTP) system for the determination of quinoline without deoxidization procedure was developed based on the external heavy atom effect of dibromopropane (DBP), the RTP maximum wavelengths lambda(ex)/lambda(em) = 273/496nm. The difference of heavy atom effect betw... |
10230040 | Isolation and characterization of di- and tri-mannosyl-cyclomaltoheptaoses (beta-cyclodextrins) produced by reverse action of alpha-mannosidase from jack bean. | Di- and tri-mannosyl-cyclomaltoheptaoses (beta-cyclodextrins, beta CDs), which were synthesized together with monomannosyl-beta CD in a large-scale production by reverse action of alpha-mannosidase from jack bean, were isolated and purified by HPLC. The structures of seven isomers of di-mannosyl-beta CD and six isomers... |
10099878 | Evolutionary conservation of whole homeologous chromosome arms in the Akodont rodents Bolomys and Akodon (Muridae, Sigmodontinae): maintenance of interstitial telomeric segments (ITBs) in recent event of centric fusion. | We have identified the almost complete correspondence of whole chromosome arms between the karyotypes of Bolomys lasiurus (2n = 33, 34) and Akodon montensis (2n = 24, 25) using comparative analysis of the GTG-banding patterns. To explain the karyotypic differentiation of the species, tandem and centric fusions, pericen... |
10099877 | Squash procedure for protein immunolocalization in meiotic cells. | Several techniques have been developed for protein immunolocalization in meiotic cells. However, most of them include treatments that lead to cell disruption and are only suitable for prophase-I cells. We describe a novel squash procedure of cell preparation for protein immunolabelling of different meiotic stages. This... |
10099876 | Molecular cytogenetic analysis of tetraploid and hexaploid Aegilops crassa. | The distribution of highly repetitive DNA sequences on chromosomes of tetraploid and hexaploid cytotypes of Aegilops crassa (Dcr1Xcr and Dcr1XcrDcr2 genomes) was studied using C-banding and in situ hybridization analyses with the pSc119, pAs1 and pTa794 DNA clones. In total, 14 tetraploid and five hexaploid accessions ... |
10099875 | Polymorphism of the nucleolus organizer regions (NORs) in Physalaemus petersi (Amphibia, Anura, Leptodactylidae) detected by silver staining and fluorescence in situ hybridization. | The nucleolus organizer regions (NORs) of both karyotypes I and II of Physalaemus petersi (Jiménez de la Espada, 1872) from the Brazilian Amazon were studied by Giemsa staining, and by the Ag-NOR method. Karyological group I specimens were also studied by the fluorescence in situ hybridization (FISH) technique. Multipl... |
10099874 | Sequence of DNA replication in Allium fistulosum chromosomes during S-phase. | Bromodeoxyuridine pulse labelling and immunodetection were applied to synchronized Allium fistulosum cells to study sequential changes in the chromosome replication pattern during S-phase. The replication patterns were classified into five main types depending on the location of the replication signals: (1) over the wh... |
10099873 | Mapping the distribution of the telomeric sequence (T2AG3)n in the Macropodoidea (Marsupialia), by fluorescence in situ hybridization. I. The swamp wallaby, Wallabia bicolor. | Thylogale spp. (pademelons) retain the plesiomorphic (ancestral) 2n = 22 karyotype for the marsupial family Macropodidae (kangaroos and wallabies). The swamp wallaby, Wallabia bicolor, has the most derived macropodid karyotype with the lowest chromosome number (2n = 10 female, 11 male), and a multiple sex chromosome sy... |
10099872 | Conformation of replicated segments of chromosome fibres in human S-phase nucleus. | Recent statistical analysis of the folding of G0/G1 chromosomes using fluorescence in situ hybridization (FISH) allowed development of a random walk/giant loop model of chromosome structure. According to this model there are two levels of organization of G0/G1 chromosome fibres. On the first level, the fibres are arran... |
10189280 | Effect of hydroxypropyl-beta-cyclodextrin and pH on the solubility of levemopamil HCl. | Levemopamil was solubilized by varying the concentration of hydroxypropyl-beta-cyclodextrin (HPbetaCD) and by the alteration of pH. The drug molecule has two sites for possible complexation with HPbetaCD, creating the possibility of either 1:1 or 1:2 complexation. The solubility as a function of HPbetaCD concentration ... |
10189267 | Inclusion complexation of ziprasidone mesylate with beta-cyclodextrin sulfobutyl ether. | Ziprasidone is an antipsychotic agent indicated primarily for the treatment of schizophrenia. An intramuscular dosage form of ziprasidone was developed using beta-cyclodextrin sulfobutyl ether (SBECD) to solubilize the drug by complexation. Inclusion complexation of ziprasidone mesylate (ZM) with SBECD was studied by c... |
9951729 | Clp protease complexes and their diversity in chloroplasts. | The Clp proteases represent a large, ancient ATP-dependent protease family which in higher plants is known to be located in chloroplasts. The soluble, presumably multisubunit, enzyme of the organelle stroma is of dual genetic origin. It consists of a nuclear-encoded, regulatory subunit ClpC, which is an ATPase, and a p... |
9934477 | Tracermer signal generators: an arborescent approach to the incorporation of multiple chemiluminescent labels. | The synthesis, conjugation, and chemiluminescent evaluation of zero, first, and second order acridinium-based Tracermer signal generators are described. Members of this family of labels have potential use as tracers in diagnostic assays and are structurally similar to arborol dendrimers. Tracermer-BSA conjugates showed... |
9931456 | Selection of a cDNA clone for chicken high-mobility-group 1 (HMG1) protein through its unusually conserved 3'-untranslated region, and improved expression of recombinant HMG1 in Escherichia coli. | Screening of cDNA libraries for the homologous vertebrate proteins high mobility group (HMG) 1 and 2 using DNA probes based on the coding sequences is likely to result in isolation of both HMG1 and HMG2 clones, as well as pseudogenes, which may be transcribed at low levels. However, the 3'-untranslated regions (UTRs) o... |
9932808 | Separation of oligonucleotides and DNA fragments by capillary electrophoresis in dynamically and permanently coated capillaries, using a copolymer of acrylamide and beta-D-glucopyranoside as a new low viscosity matrix with high sieving capacity. | New copolymers of acrylamide and beta-D-glucopyranoside were synthesized and characterized. The different reactivity of the two monomers towards radical polymerization meant we could control the growth of the polymer chains whose length was inversely related to the number of glucose residues incorporated in the copolym... |
9924974 | Supramolecular ligands: monomer structure and protein ligation capability. | The aim of this work was to define the chemical structure of compounds self-assembling in water solutions, which appear to interact with proteins as single ligands with their supramolecular nature preserved. For this purpose the ligation to proteins of bis azo dyes, represented by Congo red and its derivatives with des... |
9922152 | Characterization of the transthyretin acid denaturation pathways by analytical ultracentrifugation: implications for wild-type, V30M, and L55P amyloid fibril formation. | Analytical ultracentrifugation methods were utilized to further characterize the acid denaturation pathways of wild-type, V30M, and L55P transthyretin (TTR) that generate intermediates leading to amyloid fibril formation and possibly the diseases senile systemic amyloidosis and familial amyloid polyneuropathy. Equilibr... |
9920403 | Thiol-disulfide redox buffers maintain a structure of immunoglobulin A that is essential for optimal in vitro binding to secretory component. | We have shown that human secretory component (SC) binds in vitro to different samples of human and murine dimeric immunoglobulin A (IgA). The binding ratio in the IgA/SC complex is 1:1. IgA which is stably bound to SC is separated from unreacted IgA by anion exchange chromatography. A part of IgA/SC complexes formed in... |
9919997 | Evaluation and optimisation of separation buffers for the determination of corticosteroids with micellar electrokinetic capillary chromatography (MECC). | Separation buffers for the determination of the corticosteroids cortisone, hydrocortisone, prednisone and prednisolone with micellar electrokinetic chromatography were developed with respect to separation efficacy and the migration times, depending on the type and the concentration of the organic modifier acetonitrile ... |
9919995 | An improved HPLC method overcoming Beer's law deviations arising from supramolecular interactions in tolfenamic acid and cyclodextrins complexes. | Inclusion complexes of tolfenamic acid (TA), a non-steroidal anti-inflammatory drug, with methyl-beta cyclodextrin and hydroxypropyl-beta cyclodextrin were prepared and characterised. Spectrophotometric, chromatographic (RP-HPLC) and 1H NMR studies of the complexes were conducted. It was observed that cyclodextrins inf... |
9919982 | Stereoselective determination of S-naproxen in tablets by capillary electrophoresis. | A capillary electrophoresis (CE) method was developed for the stereoselective determination of the non-steroidal anti-inflammatory drug (NSAID), S-naproxen, in tablets. Several beta-cyclodextrin derivatives (CDs) were tested as chiral selectors, including sulfobutyl-beta-CD (SBCD), carboxymethyl-beta-CD (CMCD), dimethy... |
9919962 | Capillary electrophoretic separation of weak base enantiomers using the single-isomer heptakis-(2,3-dimethyl-6-sulfato)-beta-cyclodextrin as resolving agent and methanol as background electrolyte solvent. | The sodium salt of the single-isomer, heptakis-(2,3-dimethyl-6-sulfato)-beta-cyclodextrin (HDMS-betaCD) was used as resolving agent in the capillary electrophoretic (CE) separation of weak base enantiomers in pure methanol background electrolytes (BEs). According to the requirements of the charged resolving agent migra... |
9919961 | Enantiomeric separation of pirlindole by liquid chromatography using different types of chiral stationary phases. | The enantioseparation of pirlindole by liquid chromatography (LC) was investigated using three different chiral stationary phases (CSPs) containing either cellulose tris-(3,5-dimethylphenylcarbamate) (Chiralcel OD-R), ovomucoid (OVM) or beta-cyclodextrin (beta-CD). The effects of the mobile phase pH on retention, enant... |
9914193 | Applications of dendrimers in bio-organic chemistry. | Dendrimers represent a new class of highly branched polymers whose interior cavities and multiple peripheral groups facilitate potential applications in biomedicine and bio-organic chemistry. Major advances in the past year were made in the synthesis and study of new carbohydrate, nucleic acid, and peptide dendrimers, ... |
9916995 | Death associated proteins (DAPs): from gene identification to the analysis of their apoptotic and tumor suppressive functions. | The process of apoptosis (programmed cell death) has become the subject of intensive and extensive research over the past few years. Various approaches are being used to identify and study genes which function as positive mediators of apoptosis. Here, we address a novel approach of gene cloning aimed at isolating intra... |
9894808 | Purification and activity study of the A- and B-chains of cinnamomin, a type II ribosome-inactivating protein. | The strong hydrophobic interaction between the A- and B-chains of cinnamomin, a type II ribosome-inactivating protein, makes it difficult to separate A- and B-chains after the disulfide bond is broken. We failed to separate the A-chain from B-chain of cinnamomin using methods under usual conditions. A convenient method... |
9893711 | Identifying the conformational state of bi-liganded haemoglobin. | While most researchers agree on the global features of cooperative ligand binding to haemoglobin (Hb), the internal mechanisms remain open to debate. This is not due to inaccurate measurements, but is rather a consequence of the cooperative ligand binding that decreases the equilibrium populations of the partially liga... |
9893709 | Structure, function and metabolism of sialic acids. | Sialic acids represent a family of sugar molecules with an unusual and highly variable chemical structure that are found mostly in the terminal position of oligosaccharide chains on the surface of cells and molecules. These special features enable them to fulfil several important and even diametrical biological functio... |
9892079 | Determination of 2-hydroxypropyl-gamma-cyclodextrin in plasma of cynomolgus monkeys after oral administration by gas chromatography-mass spectrometry. | This report describes a specific and highly sensitive gas chromatography-mass spectrometry (GC-MS) assay for the analysis of industrially produced 2-hydroxypropyl-gamma-cyclodextrin, a heterogeneous mixture of homologues and isomers, in plasma of cynomolgus monkeys. Instead of analyzing the polysaccharide mixture as a ... |
9885899 | The effect of epitope variation on the profile of cytotoxic T lymphocyte responses to the HIV envelope glycoprotein. | To address the relationship between viral and host factors during HIV infection, we analyzed the effect of viral mutations on T cell responses in seropositive, asymptomatic HLA-A2+ individuals using four envelope (env)-specific peptides with the HLA-A*0201 binding motif. We showed that the natural sequence variation wa... |
9885875 | Acquired neuromuscular disorders in critically ill patients: a systematic review. Groupe de Reflexion et d'Etude sur les Neuromyopathies En Reanimation. | <h4>Objective</h4>To summarize the prospective clinical studies of neuromuscular abnormalities in intensive care unit (ICU) patients. STUDY IDENTIFICATION AND SELECTION: Studies were identified through MEDLINE, EMBASE, references in primary and review articles, personal files, and contact with authors. Through duplicat... |
9884082 | Pharmacological modulation of GABA(A) receptor-mediated postsynaptic potentials in the CA1 region of the rat hippocampus. | It is unclear whether GABA(A) receptor-mediated hyperpolarizing and depolarizing synaptic potentials (IPSP(A)s and DPSP(A)s, respectively) are evoked by (a) the same populations of GABAergic interneurones and (b) exhibit similar regulation by allosteric modulators of GABA(A) receptor function. We have attempted to addr... |
9880905 | Cyclofructins with six to ten beta-(1-->2)-linked fructofuranose units: geometries, electrostatic profiles, lipophilicity patterns, and potential for inclusion complexation. | Cyclofructins composed of six (1, "CF6") to ten (5, "CF10") beta-(1-->2)-linked fructofuranose units were subjected to conformational analysis using Monte Carlo simulations based on the PIMM91 force-field. Breaking the molecular symmetry partially by alternating inclination of the spiro-type anellated fructofuranoses r... |
9878347 | Analysis of X-ray diffraction from fibres of Pf1 Inovirus (filamentous bacteriophage) shows that the DNA in the virion is not highly ordered. | X-ray fibre diffraction patterns of well-aligned Pf1 filamentous bacteriophage show sharp layer-lines attributable to an ordered helical array of protein subunits. Electron density maps calculated from the intensity on these layer-lines show no evidence for DNA following the symmetry of the protein, nor is there eviden... |
9876874 | Transglutaminase-catalyzed protein cross-linking in the molecular program of apoptosis and its relationship to neuronal processes. | 1. One type of transglutaminase is usually accumulated in various forms of naturally occurring cell death and apoptosis. The accumulated enzyme is activated during the death process, leading to the formation of cross-linked protein structures. Degradation of the cross-linked apoptotic bodies results in the elevation of... |
9874235 | Biophysical characterisation of lysozyme binding to LPS Re and lipid A. | The binding of lysozyme to bacterial deep rough mutant lipopolysaccharide (LPS) Re and to its lipid moiety lipid A, the 'endotoxic principle' of LPS, was investigated using biophysical techniques. The beta<-->alpha gel to liquid crystalline phase transition, the nature of the functional groups of the endotoxins, the se... |
9874216 | Expression of genes encoding the E2 and E3 components of the Bacillus stearothermophilus pyruvate dehydrogenase complex and the stoichiometry of subunit interaction in assembly in vitro. | Genes encoding the dihydrolipoyl acetyltransferase (E2) and dihydrolipoyl dehydrogenase (E3) components of the pyruvate dehydrogenase (PDH) multienzyme complex from Bacillus stearothermophilus were overexpressed in Escherichia coli. The E2 component was purified as a large soluble aggregate (molecular mass > 1 x 10(6) ... |
9868914 | Enantiomeric separations of terbutaline by CE with a sulfated beta-cyclodextrin chiral selector: a quantitative binding study. | Sulfated beta-cyclodextrin, a negatively charged chiral selector, was used for the enantiomeric separation of racemic terbutaline by capillary electrophoresis. Chiral separation was found to increase with decreasing cyclodextrin concentration. Host-guest complex binding constants for this system were determined by UV d... |
9868766 | Feasibility of using prokaryote biosensors to assess acute toxicity of polycyclic aromatic hydrocarbons. | The aim of this study was to assess the acute toxicity of polycyclic aromatic hydrocarbons using lux-marked bacterial biosensors. Standard solutions of phenanthrene, pyrene and benzo[a]pyrene were produced using 50 mM hydroxpropyl-beta-cyclodextrin solution which contained each respective polycyclic aromatic hydrocarbo... |
9864375 | Autocrine tumor necrosis factor (TNF) and lymphotoxin (LT) alpha differentially modulate cellular sensitivity to TNF/LT-alpha cytotoxicity in L929 cells. | Tumor necrosis factor (TNF) and lymphotoxin (LT) alpha are structurally and functionally related cytokines. We expressed the TNF and LT-alpha genes in murine fibrosarcoma L929r2 cells, which can be sensitized to TNF/LT-alpha-dependent necrosis by inhibitors of transcription or translation. Autocrine production of murin... |
9864361 | Redundant and distinct functions for dynamin-1 and dynamin-2 isoforms. | A role for dynamin in clathrin-mediated endocytosis is now well established. However, mammals express three closely related, tissue-specific dynamin isoforms, each with multiple splice variants. Thus, an important question is whether these isoforms and splice variants function in vesicle formation from distinct intrace... |
9862800 | Evaluating precursor-directed biosynthesis towards novel erythromycins through in vitro studies on a bimodular polyketide synthase. | <h4>Background</h4>Modular polyketide synthases (PKSs) catalyse the biosynthesis of complex polyketides using a different set of enzymes for each successive cycle of chain extension. Directed biosynthesis starting from synthetic diketides is a potentially valuable route to novel polyketides. We have used a purified bim... |
9862795 | Strategies for protein-based nanofabrication: Ni2+-NTA as a chemical mask to control biologically imposed symmetry. | <h4>Background</h4>Technologies that improve control of protein orientation on surfaces or in solution, through designed molecular recognition, will expand the range of proteins that are useful for biosensors, molecular devices and biomaterials. A limitation of some proteins is their biologically imposed symmetry, whic... |
9865949 | Dominant role of local dipolar interactions in phosphate binding to a receptor cleft with an electronegative charge surface: equilibrium, kinetic, and crystallographic studies. | Stringent specificity and complementarity between the receptor, a periplasmic phosphate-binding protein (PBP) with a two-domain structure, and the completely buried and dehydrated phosphate are achieved by hydrogen bonding or dipolar interactions. We recently found that the surface charge potential of the cleft between... |
9865947 | Pulmonary surfactant-associated polypeptide C in a mixed organic solvent transforms from a monomeric alpha-helical state into insoluble beta-sheet aggregates. | In the 35-residue pulmonary surfactant-associated lipopolypeptide C (SP-C), the stability of the valyl-rich alpha-helix comprising residues 9-34 has been monitored by circular dichroism, nuclear magnetic resonance, and Fourier transform infrared spectroscopy in both a mixed organic solvent and in phospholipid micelles.... |
9860832 | Reassessment of acarbose as a transition state analogue inhibitor of cyclodextrin glycosyltransferase. | The binding of several different active site mutants of Bacillus circulans cyclodextrin glycosyltransferase to the inhibitor acarbose has been investigated through measurement of Ki values. The mutations represent several key amino acid positions, most of which are believed to play important roles in governing the prod... |
9861035 | A nucleated assembly mechanism of Alzheimer paired helical filaments. | Alzheimer's disease is characterized by two types of fibrous aggregates in the affected brains, the amyloid fibers (consisting of the Abeta-peptide, generating the amyloid plaques), and paired helical filaments (PHFs; made up of tau protein, forming the neurofibrillary tangles). Hence, tau protein, a highly soluble pro... |
9860943 | Molecular recognition of angiogenesis inhibitors fumagillin and ovalicin by methionine aminopeptidase 2. | Angiogenesis inhibitors are a novel class of promising therapeutic agents for treating cancer and other human diseases. Fumagillin and ovalicin compose a class of structurally related natural products that potently inhibit angiogenesis by blocking endothelial cell proliferation. A synthetic analog of fumagillin, TNP-47... |
9858623 | Polymorphic DNA markers in the genome of parasitic nematodes. | Polymorphic molecular markers are being identified to characterize the genomes of parasitic nematodes. The aim is to construct a map with markers evenly spread over the six chromosomes. With such a map, regions can be identified that are under selection pressure when attempts are being made to eradicate worms, be it by... |
9857196 | The structure of plasmid-encoded transcriptional repressor CopG unliganded and bound to its operator. | The structure of the 45 amino acid transcriptional repressor, CopG, has been solved unliganded and bound to its target operator DNA. The protein, encoded by the promiscuous streptococcal plasmid pMV158, is involved in the control of plasmid copy number. The structure of this protein repressor, which is the shortest rep... |
9857175 | FRET microscopy demonstrates molecular association of non-specific lipid transfer protein (nsL-TP) with fatty acid oxidation enzymes in peroxisomes. | The fate of fluorescently labeled pre-nsL-TP (Cy3-pre-nsL-TP) microinjected into BALB/c 3T3 fibroblasts was investigated by confocal laser scanning microscopy. The protein exhibited a distinct punctate fluorescence pattern and colocalized to a high degree with the immunofluorescence pattern for the peroxisomal enzyme a... |
9852149 | The localization of myosin VI at the golgi complex and leading edge of fibroblasts and its phosphorylation and recruitment into membrane ruffles of A431 cells after growth factor stimulation. | Myosin VI is an unconventional myosin that may play a role in vesicular membrane traffic through actin rich regions of the cytoplasm in eukaryotic cells. In this study we have cloned and sequenced a cDNA encoding a chicken intestinal brush border myosin VI. Polyclonal antisera were raised to bacterially expressed fragm... |
9852049 | Artificial chaperone-assisted refolding of citrate synthase. | The power of genetic engineering methods, along with increasing genomic information, makes heterologous expression of proteins an extremely important biochemical tool. Unfortunately, proteins obtained in this way often are not in their native form, and folding becomes a crucial step in protein production. We have recen... |
9852032 | Identification of two binding domains, one for peptidoglycan and another for a secondary cell wall polymer, on the N-terminal part of the S-layer protein SbsB from Bacillus stearothermophilus PV72/p2. | First studies on the structure-function relationship of the S-layer protein from B. stearothermophilus PV72/p2 revealed the coexistence of two binding domains on its N-terminal part, one for peptidoglycan and another for a secondary cell wall polymer (SCWP). The peptidoglycan binding domain is located between amino aci... |
9852023 | Superimposition of tyrR protein-mediated regulation on osmoresponsive transcription of Escherichia coli proU in vivo. | Osmotic regulation of proU expression in the enterobacteria is achieved, at least in part, by a repression mechanism involving the histone-like nucleoid protein H-NS. By the creation of binding sites for the TyrR regulator protein in the vicinity of the sigma70-controlled promoter of proU in Escherichia coli, we were a... |
9852011 | Functional similarities between the Listeria monocytogenes virulence regulator PrfA and cyclic AMP receptor protein: the PrfA* (Gly145Ser) mutation increases binding affinity for target DNA. | Most Listeria monocytogenes virulence genes are positively regulated by the PrfA protein, a transcription factor sharing sequence similarities with cyclic AMP (cAMP) receptor protein (CRP). Its coding gene, prfA, is regulated by PrfA itself via an autoregulatory loop mediated by the upstream PrfA-dependent plcA promote... |
9852010 | Expression of the Bacillus subtilis acsA gene: position and sequence context affect cre-mediated carbon catabolite repression. | In Bacillus subtilis, carbon catabolite repression (CCR) of many genes is mediated at cis-acting carbon repression elements (cre) by the catabolite repressor protein CcpA. Mutations in transcription-repair coupling factor (mfd) partially relieve CCR at cre sites located downstream of transcriptional start sites by abol... |
9844026 | Carbohydrate binding and resistance to proteolysis control insecticidal activity of Griffonia simplicifolia lectin II. | Griffonia simplicifolia leaf lectin II (GSII), a plant defense protein against certain insects, consists of an N-acetylglucosamine (GlcNAc)-binding large subunit with a small subunit having sequence homology to class III chitinases. Much of the insecticidal activity of GSII is attributable to the large lectin subunit, ... |
9844002 | Isolation and characterization of iron-independent positive dominant mutants of the diphtheria toxin repressor DtxR. | It is well known that the functional activity of the diphtheria toxin repressor DtxR is controlled by iron, which serves as an essential cofactor necessary for activation of target DNA binding by this regulatory element. In this communication, we describe the isolation and characterization of a unique series of DtxR mu... |
9844000 | Suppression of an absolute defect in type IV pilus biogenesis by loss-of-function mutations in pilT, a twitching motility gene in Neisseria gonorrhoeae. | Type IV pili of Neisseria gonorrhoeae, the Gram-negative etiologic agent of gonorrhea, facilitate colonization of the human host. Gonococcal PilT, a protein belonging to a large family of molecules sharing a highly conserved nucleotide binding domain motif, has been shown to be dispensable for organelle biogenesis but ... |
9843959 | A cytosolic activity distinct from crm1 mediates nuclear export of protein kinase inhibitor in permeabilized cells. | The leucine-rich nuclear export signal (NES) is used by a variety of proteins to facilitate their delivery from the nucleus to the cytoplasm. One of the best-studied examples, protein kinase inhibitor (PKI), binds to the catalytic subunit of protein kinase A in the nucleus and mediates its rapid export to the cytoplasm... |
9843876 | Pregnancy-induced changes in central response to atrial distension mimicked by progesterone metabolite. | In virgin female rats, atrial distension (an index of blood volume expansion) causes an increase in c-fos expression in the paraventricular nucleus of the lateral hypothalamus. During pregnancy, this response is markedly attenuated. We tested the effects of 3alpha-hydroxy-5alpha-pregnan-20-one (3alpha-OH-DHP) on activa... |
9843582 | Functional characterization of a Nup159p-containing nuclear pore subcomplex. | Nup159p/Rat7p is an essential FG repeat-containing nucleoporin localized at the cytoplasmic face of the nuclear pore complex (NPC) and involved in poly(A)+ RNA export and NPC distribution. A detailed structural-functional analysis of this nucleoporin previously demonstrated that Nup159p is anchored within the NPC throu... |
9843515 | Localization of a protein-DNA interface by random mutagenesis. | The type I restriction and modification enzymes do not possess obvious DNA-binding motifs within their target recognition domains (TRDs) of 150-180 amino acids. To identify residues involved in DNA recognition, changes were made in the amino-TRD of EcoKI by random mutagenesis. Most of the 101 substitutions affecting 79... |
9843510 | Recruitment of a protein complex containing Tat and cyclin T1 to TAR governs the species specificity of HIV-1 Tat. | Human cyclin T1 (hCycT1), a major subunit of the essential elongation factor P-TEFb, has been proposed to act as a cofactor for human immunodeficiency virus type 1 (HIV-1) Tat. Here, we show that murine cyclin T1 (mCycT1) binds the activation domain of HIV-1 Tat but, unlike hCycT1, cannot mediate Tat function because i... |
9843489 | Peptides that block hepatitis B virus assembly: analysis by cryomicroscopy, mutagenesis and transfection. | Peptides selected to bind to hepatitis B virus (HBV) core protein block interaction with the long viral surface antigen (L-HBsAg) in vitro. High resolution electron cryomicroscopy showed that one such peptide binds at the tips of the spikes of the core protein shell. The peptides contain two basic residues; changing ei... |
9841883 | Identification of the separate domains in the hepatic glycogen-targeting subunit of protein phosphatase 1 that interact with phosphorylase a, glycogen and protein phosphatase 1. | Deletion and mutational analyses of the rat liver glycogen-targeting subunit (GL) of protein phosphatase 1 (PP1) have identified three separate domains that are responsible for binding of PP1, glycogen and phosphorylase a. The glycogen-binding domain spans the centre of GL between residues 144 and 231 and appears to be... |
9841861 | Tocopherol synthesis from homogentisate in Capsicum anuum L. (yellow pepper) chromoplast membranes: evidence for tocopherol cyclase. | The present study shows for the first time appreciable tocopherol cyclase activities in plastidial membrane preparations of Capsicum annuum L. (yellow pepper) fruits. When chromoplast membranes from yellow peppers were incubated with [3H]homogentisate and phytyl pyrophosphate under strictly reducing conditions, all bio... |
9841679 | Posttranscriptional control of gene expression in yeast. | Studies of the budding yeast Saccharomyces cerevisiae have greatly advanced our understanding of the posttranscriptional steps of eukaryotic gene expression. Given the wide range of experimental tools applicable to S. cerevisiae and the recent determination of its complete genomic sequence, many of the key challenges o... |
9841669 | Virus maturation by budding. | Enveloped viruses mature by budding at cellular membranes. It has been generally thought that this process is driven by interactions between the viral transmembrane proteins and the internal virion components (core, capsid, or nucleocapsid). This model was particularly applicable to alphaviruses, which require both spi... |
9841667 | Molecular biology and pathogenicity of mycoplasmas. | The recent sequencing of the entire genomes of Mycoplasma genitalium and M. pneumoniae has attracted considerable attention to the molecular biology of mycoplasmas, the smallest self-replicating organisms. It appears that we are now much closer to the goal of defining, in molecular terms, the entire machinery of a self... |
9836609 | Polyanion inhibitors of HIV and other viruses. 7. Polyanionic compounds and polyzwitterionic compounds derived from cyclodextrins as inhibitors of HIV transmission. | New polyanionic compounds were obtained from radical addition of thiomalic acid and mercaptopropionic acid onto perallylated cyclodextrins (CDs) under UV irradiation with a catalytic amount of alpha,alpha'-azobis(isobutyronitrile). All these polyanions, bearing 18-48 carboxylate groups, inhibited human immunodeficiency... |
9836717 | Comparison of two homogeneous assays with a precipitation method and an ultracentrifugation method for the measurement of HDL-cholesterol. | We report on the performance of four HDL-cholesterol assays: a homogeneous method based on polyethylene glycol-modified enzymes/alpha-cyclodextrin sulfate (PEGME; Kyowa); a homogeneous method based on polyanion-polymer/detergent (PPD; Daiichi); the usual precipitation method with phosphotungstic acid/MgCl2 (PTA); and a... |
9836576 | Lowering the entropic barrier for binding conformationally flexible inhibitors to enzymes. | The design of inhibitors with enhanced potency against proteolytic enzymes has many applications for the treatment of human diseases. In addition to the optimization of chemical interactions between the enzyme and inhibitor, the binding affinity can be increased by constraining the inhibitor to the conformation that is... |
9835575 | Procaryotic expression of single-chain variable-fragment (scFv) antibodies: secretion in L-form cells of Proteus mirabilis leads to active product and overcomes the limitations of periplasmic expression in Escherichia coli. | Recently it has been demonstrated that L-form cells of Proteus mirabilis (L VI), which lack a periplasmic compartment, can be efficiently used in the production and secretion of heterologous proteins. In search of novel expression systems for recombinant antibodies, we compared levels of single-chain variable-fragment ... |
9835518 | Structure-based design of novel dihydroalkoxybenzyloxopyrimidine derivatives as potent nonnucleoside inhibitors of the human immunodeficiency virus reverse transcriptase. | Two highly potent dihydroalkoxybenzyloxopyrimidine (DABO) derivatives targeting the nonnucleoside inhibitor (NNI) binding site of human immunodeficiency virus (HIV) reverse transcriptase (RT) have been designed based on the structure of the NNI binding pocket and tested for anti-HIV activity. Our lead DABO derivative, ... |
9829990 | Glutamate residues required for substrate binding and cleavage activity in mitochondrial processing peptidase. | Mitochondrial processing peptidase, a metalloendopeptidase consisting of alpha- and beta-subunits, specifically recognizes a large variety of mitochondrial precursor proteins and cleaves off N-terminal extension peptides. The enzyme requires the basic amino acid residues in the extension peptides for effective and spec... |
9828175 | Cyclodextrin removes cholesterol from mouse sperm and induces capacitation in a protein-free medium. | Cyclodextrin, which stimulates cholesterol efflux from cells, was examined for its ability to induce capacitation of mouse spermatozoa. A chemically defined, protein-free medium was used for in vitro fertilization of cumulus-free mouse eggs. Fertilization did not occur in modified Krebs-Ringer bicarbonate medium (TYH) ... |
9826770 | Dehydromonocrotaline generates sequence-selective N-7 guanine alkylation and heat and alkali stable multiple fragment DNA crosslinks. | Monocrotaline is a pyrrolizidine alkaloid known to cause toxicity in humans and animals. Its mechanism of biological action is still unclear although DNA crosslinking has been suggested to a play a role in its activity. In this study we found that an active metabolite of monocrotaline, dehydromonocrotaline (DHM), alkyl... |
9826766 | Optimization of excimer-forming two-probe nucleic acid hybridization method with pyrene as a fluorophore. | A previously presented homogeneous assay method, named the excimer-forming two-probe nucleic acid hybridization (ETPH) method, is based on specific excimer formation between two pyrenes attached at the neighboring terminals of two sequential probe oligonucleotides complementary to a single target. In this study, we inv... |
9826753 | Cationic porphyrins: novel delivery vehicles for antisense oligodeoxynucleotides. | Cationic porphyrins form stable complexes with oligodeoxynucleotides. To evaluate delivery, we used a 20mer phosphorothioate oligomer (Isis 3521) targeted to the 3'-untranslated region of the PKC-alpha mRNA, and complexed it with porphyrin. The expression of PKC-alpha protein and mRNA in T24 bladder carcinoma cells was... |
9826611 | Experimental and Monte Carlo simulation studies of the thermodynamics of polyethyleneglycol chains grafted to lipid bilayers. | Experimental measurements of the affinity of binding of fluorescent acylated polyethyleneglycol (PEG) conjugates to bilayers containing varying levels of phosphatidylethanolamine-PEGs (PE-PEGs) have been combined with Monte Carlo simulations to investigate the properties of the polymer chains at a PEG-grafted lipid int... |
9826609 | Total lipids with short and long acyl chains from Acholeplasma form nonlamellar phases. | The cell-wall-less bacterium Acholeplasma laidlawii A-EF22 synthesizes eight glycerolipids. Some of them form lamellar phases, whereas others are able to form normal or reversed nonlamellar phases. In this study we examined the phase properties of total lipid extracts with limiting average acyl chain lengths of 15 and ... |
9826588 | Role of hydrophobicity and solvent-mediated charge-charge interactions in stabilizing alpha-helices. | A theoretical study to identify the conformational preferences of lysine-based oligopeptides has been carried out. The solvation free energy and free energy of ionization of the oligopeptides have been calculated by using a fast multigrid boundary element method that considers the coupling between the conformation of t... |
9826587 | Local rules simulation of the kinetics of virus capsid self-assembly. | A computer model is described for studying the kinetics of the self-assembly of icosahedral viral capsids. Solution of this problem is crucial to an understanding of the viral life cycle, which currently cannot be adequately addressed through laboratory techniques. The abstract simulation model employed to address this... |
9826338 | Sulfatide from the pig jejunum brush border epithelial cell surface is involved in binding of Escherichia coli enterotoxin b. | Using a quantitative dot blot overlay assay of polyvinylidene difluoride membranes, we investigated the ability of Escherichia coli heat-stable enterotoxin b (STb) to bind to various glycolipids of defined structure. STb bound strongly to acidic glycosphingolipids, including sulfatide (or 3'-sulfogalactosylceramide) an... |
9822721 | Requirement for the NINAC kinase/myosin for stable termination of the visual cascade. | Activation of the Drosophila photoresponse is a rapid process that results in plasma membrane Ca2+ and Na+ conductances. Ca2+ functions in negative feedback regulation of Drosophila vision including deactivation. Protein kinase C (PKC) binds directly to Ca2+ and is required for deactivation. However, the consequences o... |
9819417 | Inhibition of double-stranded RNA-dependent protein kinase PKR by vaccinia virus E3: role of complex formation and the E3 N-terminal domain. | The human double-stranded RNA (dsRNA)-dependent protein kinase PKR inhibits protein synthesis by phosphorylating translation initiation factor 2alpha (eIF2alpha). Vaccinia virus E3L encodes a dsRNA binding protein that inhibits PKR in virus-infected cells, presumably by sequestering dsRNA activators. Expression of PKR ... |
9811778 | Morbillivirus downregulation of CD46. | There is evidence that CD46 (membrane cofactor protein) is a cellular receptor for vaccine and laboratory-passaged strains of measles virus (MV). Following infection with these MV strains, CD46 is downregulated from the cell surface, and consequent complement-mediated lysis has been shown to occur upon infection of a h... |
9811773 | Alphavirus replicase protein NSP1 induces filopodia and rearrangement of actin filaments. | Expression of the NSP1 protein of Semliki Forest virus and Sindbis virus in cultured cells induced filopodia-like extensions containing NSP1 but not F actin. The actin stress fibers disappeared, whereas vimentin, keratin, and tubulin networks remained intact. The effects of NSP1 were dependent on its palmitoylation but... |
9811734 | Replicative functions of minute virus of mice NS1 protein are regulated in vitro by phosphorylation through protein kinase C. | NS1, the major nonstructural protein of the parvovirus minute virus of mice, is a multifunctional phosphoprotein which is involved in cytotoxicity, transcriptional regulation, and initiation of viral DNA replication. For coordination of these various functions during virus propagation, NS1 has been proposed to be regul... |
9811712 | The replication protein A binding site in simian virus 40 (SV40) T antigen and its role in the initial steps of SV40 DNA replication. | Physical interactions of simian virus 40 (SV40) large tumor (T) antigen with cellular DNA polymerase alpha-primase (Pol/Prim) and replication protein A (RPA) appear to be responsible for multiple functional interactions among these proteins that are required for initiation of viral DNA replication at the origin, as wel... |
9811700 | Interaction of poly(rC) binding protein 2 with the 5' noncoding region of hepatitis A virus RNA and its effects on translation. | Utilization of internal ribosome entry segment (IRES) structures in the 5' noncoding region (5'NCR) of picornavirus RNAs for initiation of translation requires a number of host cell factors whose distribution may vary in different cells and whose requirement may vary for different picornaviruses. We have examined the r... |
9799720 | Conversion of cyclodextrin into high-amylose starch of low molecular mass by means of cyclodextrin glucanotransferase. | alpha-Cyclodextrin (CD) was converted by Bacillus macerans cyclodextrin glucanotransferase into highly insoluble high-amylose starch with a low average degree of polymerization (56-73), in yields as high as 78% over a wide range of temperatures (25-70 degreesC). Ability to undergo this conversion was highly concentrati... |
9745698 | Radiostrontium analytical method using crown-ether compound and Cerenkov counting and its applications in environmental monitoring. | The radiostrontium content in environmental samples was determined by chemical analysis by means of the fuming nitric acid method and ion exchange method with low-level beta counting and the newly developed method using crown-ether compound. Counting was performed with a low-background counter and a liquid scintillatio... |
38239500 | Adenosine A<sub>3</sub> Receptors and Viability of Astrocytes. | We investigated the role of the A<sub>3</sub> adenosine receptor in cells of the astroglial lineage (both rat primary astrocytes and human astrocytoma ADF cells) by means of the selective A<sub>3</sub> agonists N<sup>6</sup>-(3-iodobenzyl)-adenosine-5'-N-methyluronamide (IB-MECA) and CI-IB-MECA, and by utilizing the se... |
31808655 | A<sub>3</sub> Adenosine Receptors: Protective vs. Damaging Effects Identified Using Novel Agonists and Antagonists. | Investigation of the physiologic role of the A<sub>3</sub> adenosine receptor has been facilitated by the availability of selective agonists and antagonists. Selective agonists include IB-MECA and the 2-chloro derivative Cl-IB-MECA. Selective antagonists have been identified and designed with the aid of molecular model... |
29711148 | Supramolecular Assembly of Heterogeneous Multiporphyrin Arrays-Structures of [{Zn<sup>II</sup> (tpp)}<sub>2</sub> (tpyp)] and the Coordination Polymer [{[Mn<sup>III</sup> (tpp)]<sub>2</sub> (tpyp)(ClO<sub>4</sub> )<sub>2</sub> }<sub>∞</sub> ]. | Channels make up 46% of the crystal volume: A two-dimensional coordination polymer of exceptional structural regularity (see schematic drawing; tpp=tetraphenylporphyrin, tpyp=tetrapyridylporphyrin) was assembled from [Mn<sup>III</sup> (tpp)]⋅ClO<sub>4</sub> and tpyp. The crystal packing of these polymers yields an open... |
29711147 | A New Strategy for the Destabilization of Double-Stranded Nucleic Acids by Phenylalkylamine Derivatives. | Drastic reduction in the melting points indicates considerable destabilization of double-stranded (ds) nucleic acids by stabilization of unfolded polymer parts with phenylalkylamine derivatives. These ligands cannot intercalate into ds duplex forms, but can stack with unfolded parts if the spacers separating the phenyl... |
29711144 | Windmill-Like Porphyrin Arrays as Potent Light-Harvesting Antenna Complexes. | Up to 14 porphyrin rings are present in the title compounds 1, which are readily available with high regioselectivity from linear nickel-zinc porphyrins. Upon irradiation with light a rapid energy transfer from the peripheral porphyrin rings to the diporphyrin core takes place. |
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