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7606360 | Comparative mapping of YRRM- and TSPY-related cosmids in man and hominoid apes. | Using chromosomal in situ hybridization it has been demonstrated that specific members of the YRRM and the TSPY families are multicopy and Y chromosome specific in hominoids. After hybridization with the YRRM-related cosmid A5F and the TSPY-related cosmids cos36 and cY91, a reverse and complementary pattern of main and... |
7606359 | Microdissection of the Y chromosome and fluorescence in situ hybridization analysis of the sex chromosomes of lake trout, Salvelinus namaycush. | Lake trout, Salvelinus namaycush, is one of the few salmonids with morphologically differentiated sex chromosomes. Genetic analysis suggested that the sex-determining region of this species lies on the short arm of the Y chromosome. The differential arm of the Y chromosome was microdissected and the resulting DNA ampli... |
7606358 | DNA, histone H1 and meiotin-1 immunostaining patterns along whole-mount preparations of Lilium longiflorum pachytene chromosomes. | Meiotin-1 is a chromatin protein found in lily microsporocytes preceding and during meiosis. It reaches peak levels in the leptotene-pachytene interval. Here we report the pattern of immunostaining of meiotin-1 along pachytene chromosomes prepared using a whole-mount, synaptonemal complex spreading technique. Meiotin-1... |
7606357 | Recently amplified satellite DNA in Callithrix argentata (primates, Platyrrhini). | A satellite DNA has been cloned from the neotropical primate Callithrix argentata and designated CarB. The presence of the satellite was assayed in New and Old World primates by blot hybridization: CarB is highly amplified in the genomes of all three species belonging to the C. argentata species group (C. argentata, C.... |
7603409 | Mechanisms of membrane toxicity of hydrocarbons. | Microbial transformations of cyclic hydrocarbons have received much attention during the past three decades. Interest in the degradation of environmental pollutants as well as in applications of microorganisms in the catalysis of chemical reactions has stimulated research in this area. The metabolic pathways of various... |
7602130 | Ligand binding analysis of interleukin-2 receptor complexes using surface plasmon resonance. | In this study we have employed surface plasmon resonance to examine the kinetic binding constants of a new class of soluble cytokine receptor complexes. The solution assembly of both homomeric and heteromeric interleukin-2 receptor ectodomain complexes has been achieved using coiled-coil molecular recognition. These co... |
7601335 | Omega loops: nonregular secondary structures significant in protein function and stability. | Omega (omega-) loops, a nonregular secondary structure found in globular proteins, are characterized by a polypeptide chain that follows a loop-shaped course in three-dimensional space. They do not contain repeating backbone dihedral angles or regular patterns of hydrogen bonding; however, many omega-loops contain a la... |
7601157 | Differences in the DNA-binding properties of the HMG-box domains of HMG1 and the sex-determining factor SRY. | High-mobility-group protein 1 (HMG1) is an abundant, non-sequence-specific, chromosomal protein with two homologous, HMG-box, DNA-binding domains, A and B, and an acidic tail. The HMG-box motif also occurs, as a single copy, in some sequence-specific transcription factors, e.g. the sex-determining factor, SRY. We have ... |
7597064 | An allosteric switch controls the procoagulant and anticoagulant activities of thrombin. | Thrombin is an allosteric enzyme existing in two forms, slow and fast, that differ widely in their specificities toward synthetic and natural amide substrates. The two forms are significantly populated in vivo, and the allosteric equilibrium can be affected by the binding of effectors and natural substrates. The fast f... |
7597040 | T-cell receptor (TCR) usage in Lewis rat experimental autoimmune encephalomyelitis: TCR beta-chain-variable-region V beta 8.2-positive T cells are not essential for induction and course of disease. | Predominant usage of V beta 8.2 gene segments, encoding a T-cell receptor (TCR) beta chain variable region, has been reported for pathogenic Lewis rat T cells reactive to myelin basic protein (MBP). However, up to 75% of the alpha/beta T cells in a panel of MBP-specific T-cell lines did not display TCR V beta 8.2, V be... |
7797538 | A two-step model for lipoprotein(a) formation. | Lipoprotein(a) (Lp(a)), a risk factor for coronary artery disease, is a LDL-like particle with apolipoprotein(a) (apo(a)) covalently linked to apolipoprotein B (apoB), the main protein component of LDL. Apo(a) is highly homologous to plasminogen and its gene probably arose by duplication of the plasminogen gene. It has... |
7796882 | Pamlin, a primary mesenchyme cell adhesion protein, in the basal lamina of the sea urchin embryo. | Pamlin, a primary mesenchyme cell (PMC) adhesion protein, was isolated from the blastocoel of embryos of the sea urchin Hemicentrotus pulcherrimus. PMCs isolated from mesenchyme blastulae bound exclusively to pamlin. Pamlin is a distinctive extracellular matrix (ECM) component from reported ECM molecules in sea urchin ... |
7796819 | Macromolecular recognition through electrostatic repulsion. | In the process of genetic translation, each aminoacyl-tRNA synthetase specifically aminoacylates its cognate tRNAs and rejects the 19 other species of tRNAs. A decrease in the specificity of this reaction can result in misincorporations of amino acids into proteins and be deleterious to the cell. In the case of tyrosyl... |
7796807 | The 5-HT4 receptor: molecular cloning and pharmacological characterization of two splice variants. | Molecular cloning efforts have provided primary amino acid sequence and signal transduction data for a large collection of serotonin receptor subtypes. These include five 5-HT1-like receptors, three 5-HT2 receptors, one 5-HT3 receptor, two 5-HT5 receptors, one 5-HT6 receptor and one 5-HT7 receptor. Molecular biological... |
7790353 | Oligomerization of epidermal growth factor receptors on A431 cells studied by time-resolved fluorescence imaging microscopy. A stereochemical model for tyrosine kinase receptor activation. | The aggregation states of the epidermal growth factor receptor (EGFR) on single A431 human epidermoid carcinoma cells were assessed with two new techniques for determining fluorescence resonance energy transfer: donor photobleaching fluorescence resonance energy transfer (pbFRET) microscopy and fluorescence lifetime im... |
7789516 | Arachidonic acid binds to apolipoprotein D: implications for the protein's function. | The lipocalin apolipoprotein D (ApoD) is associated in human plasma with lecithin-cholesterol acyl transferase. It has also been found in high concentration in the fluid of gross cystic disease of the mammary gland. Using protein fluorescence quenching, it is shown that ApoD binds arachidonic acid (Ka of 1.6 x 10(8) M-... |
7783191 | Conserved structural features on protein surfaces: small exterior hydrophobic clusters. | The extent to which side-chains at the surface of globular proteins adopt well-defined conformations is a matter of some controversy and, in turn, the idea that specific interactions amongst them might make a significant contribution to defining tertiary structures would be generally seen as questionable. In at least s... |
7540134 | Invasion of epithelial cells by Shigella flexneri induces tyrosine phosphorylation of cortactin by a pp60c-src-mediated signalling pathway. | Shigella flexneri causes bacillary dysentery in humans by invading epithelial cells of the colon. Cell invasion occurs via bacterium-directed phagocytosis, a process requiring polymerization of actin at the site of bacterial entry. We show that invasion of HeLa cells by S.flexneri induces tyrosine phosphorylation of co... |
7779110 | Cyclodextrins as protein folding aids. | Aggregation of proteins is a frequent occurrence during their transition from random coil to native structure. The influence of cyclodextrins in the refolding of carbonic anhydrase under aggregating conditions was studied. Cyclodextrin prevented formation of protein aggregates during renaturation of carbonic anhydrase.... |
7778283 | Sequence determination of human papillomavirus type 6a and assembly of virus-like particles in Saccharomyces cerevisiae. | Human papillomavirus 6a (HPV6a), the most abundant HPV6 subtype, was detected in a vulvar condyloma acuminatum. The complete genome of HPV6a was cloned, and its DNA sequence was shown to be over 97% identical to the HPV6b sequence. Of the eight open reading frames (ORFs) of HPV6a, only the imputed amino acid sequence o... |
7777581 | Endogenous mutagenesis by an insertion sequence element identifies Aeromonas salmonicida AbcA as an ATP-binding cassette transport protein required for biogenesis of smooth lipopolysaccharide. | Analysis of an Aeromonas salmonicida A layer-deficient/O polysaccharide-deficient mutant carrying a Tn5 insertion in the structural gene for A protein (vapA) showed that the abcA gene immediately downstream of vapA had been interrupted by the endogenous insertion sequence element ISAS1. Immunoelectron microscopy showed... |
7777555 | Significant discrepancies between van't Hoff and calorimetric enthalpies. | In this paper we show that the usual assumption in studies of the temperature variation of equilibrium constants for equilibria of the form A+B <-->AB that a plot of ln K vs. 1/T (K = equilibrium constant, T = temperature in degrees kelvin) is a straight line with slope equal to -delta HvH/R (delta HvH = van't Hoff or ... |
7777519 | Interferon gamma signals via a high-affinity multisubunit receptor complex that contains two types of polypeptide chain. | Signaling by interferon gamma (IFN-gamma) requires two structurally related cell surface proteins: a ligand-binding polypeptide, known as the IFN-gamma receptor (IFN-gamma R), and an accessory factor. However, it is not known whether IFN-gamma forms a ternary complex with the IFN-gamma R and accessory factor to initiat... |
7777501 | Direct measurement of hydrogen bonding in DNA nucleotide bases by atomic force microscopy. | We have used self-assembled purines and pyrimidines on planar gold surfaces and on gold-coated atomic force microscope (AFM) tips to directly probe intermolecular hydrogen bonds. Electron spectroscopy for chemical analysis (ESCA) and thermal programmed desorption (TPD) measurements of the molecular layers suggested mon... |
7775630 | 17 beta-estradiol stimulates prostacyclin, but not endothelin-1, production in human vascular endothelial cells. | The exact mechanisms by which estrogens protect against occlusive vascular disorders are not known. One possibility could be an effect on vascular endothelial vasoactive compounds, such as vasodilatory prostacyclin (PGI2) and vasoconstrictory endothelin (ET-1). Here we report on the effect of 17 beta-estradiol on the s... |
7775577 | Structure of growing microtubule ends: two-dimensional sheets close into tubes at variable rates. | Observation of microtubule growth at different rates by cryo-electron microscopy reveals that the ends range from blunt to long, gently curved sheets. The mean sheet length increases with the growth rate while the width of the distributions increases with the extent of assembly. The combination of a concentration depen... |
7775460 | Site-directed mutagenesis identifies residues involved in ligand recognition in the human A2a adenosine receptor. | The A2a adenosine receptor is a member of the G-protein coupled receptor family, and its activation stimulates cyclic AMP production. To determine the residues which are involved in ligand binding, several residues in transmembrane domains 5-7 were individually replaced with alanine and other amino acids. The binding p... |
7775454 | The influence of beta subunit structure on the interaction of Na+/K(+)-ATPase complexes with Na+. A chimeric beta subunit reduces the Na+ dependence of phosphoenzyme formation from ATP. | High-affinity ouabain binding to Na+/K(+)-ATPase (sodium- and potassium-transport adenosine triphosphatase (EC 3.6.1.37)) requires phosphorylation of the alpha subunit of the enzyme either by ATP or by inorganic phosphate. For the native enzyme (alpha/beta 1), the ATP-dependent reaction proceeds about 4-fold more slowl... |
7772016 | The structure of the quinoprotein alcohol dehydrogenase of Acetobacter aceti modelled on that of methanol dehydrogenase from Methylobacterium extorquens. | The 1.94 A structure of methanol dehydrogenase has been used to provide a model structure for part of a membrane quinohaemoprotein alcohol dehydrogenase. The basic superbarrel structure and the active-site region are retained, indicating essentially similar mechanisms of action, but there are considerable differences i... |
7770773 | Repositioning of a domain in a modular polyketide synthase to promote specific chain cleavage. | Macrocyclic polyketides exhibit an impressive range of medically useful activities, and there is great interest in manipulating the genes that govern their synthesis. The 6-deoxyerythronolide B synthase (DEBS) of Saccharopolyspora erythraea, which synthesizes the aglycone core of the antibiotic erythromycin A, has been... |
7769129 | Fc gamma receptor IIIb enhances Fc gamma receptor IIa function in an oxidant-dependent and allele-sensitive manner. | Two classes of receptors for IgG, Fc gamma RIIa and Fc gamma RIIIb, both of which exist in two allelic forms, are expressed on human neutrophils. Neutrophils from normal donors, homozygous for the different allelic phenotypes of Fc gamma RIIIb, have significantly different levels of Fc gamma receptor-mediated phagocyto... |
7769092 | Purification of human very-long-chain acyl-coenzyme A dehydrogenase and characterization of its deficiency in seven patients. | Mitochondrial very-long-chain acyl-coenzyme A dehydrogenase (VLCAD) was purified from human liver. The molecular masses of the native enzyme and the subunit were estimated to be 154 and 70 kD, respectively. The enzyme was found to catalyze the major part of mitochondrial palmitoylcoenzyme A dehydrogenation in liver, he... |
7768815 | aldB, an RpoS-dependent gene in Escherichia coli encoding an aldehyde dehydrogenase that is repressed by Fis and activated by Crp. | Escherichia coli aldB was identified as a gene that is negatively regulated by Fis but positively regulated by RpoS. The complete DNA sequence determined in this study indicates that aldB encodes a 56.3-kDa protein which shares a high degree of homology with an acetaldehyde dehydrogenase encoded by acoD of Alcaligenes ... |
7768809 | Purification and characterization of a cam repressor (CamR) for the cytochrome P-450cam hydroxylase operon on the Pseudomonas putida CAM plasmid. | The cytochrome P-450cam hydroxylase operon of Pseudomonas putida PpG1 (ATCC 17543) encodes proteins responsible for early steps of the degradation of D-camphor. Transcription of this operon is negatively controlled by the cam repressor (CamR), and the expression of camR is autoregulated. CamR was purified from Escheric... |
7768617 | Affinity, conservation, and surface exposure of hemopexin-binding proteins in Haemophilus influenzae. | Haemophilus influenzae can acquire heme from hemopexin for use as a source of both essential porphyrin and iron. In classical ligand-binding studies, we observed time-dependent, saturable, and displaceable binding of human 125I-labelled hemopexin to intact cells of H. influenzae type b (Hib) strain 760705 grown in an i... |
7768601 | Characterization of a Helicobacter pylori neutrophil-activating protein. | Helicobacter pylori-associated gastritis is mainly an inflammatory cell response. In earlier work we showed that activation of human neutrophils by a cell-free water extract of H. pylori is characterized by increased expression of neutrophil CD11b/CD18 and increased adhesiveness to endothelial cells. The work reported ... |
7768599 | Characterization of the structural elements in lipid A required for binding of a recombinant fragment of bactericidal/permeability-increasing protein rBPI23. | Both human bactericidal/permeability-increasing protein (BPI) and a recombinant amino-terminal fragment of BPI (rBPI23) have been shown to bind with high affinity to the lipid A region of lipopolysaccharide (LPS) (H. Gazzano-Santoro, J. B. Parent, L. Grinna, A. Horwitz, T. Parsons, G. Theofan, P. Elsbach, J. Weiss, and... |
7766827 | Atypical Gly-X-Y sequences surround interruptions in the repeating tripeptide pattern of basement membrane collagen. | The triple-helical domains of type IV collagen chains have more than 20 sites at which the repeating (Gly-X-Y)n pattern is interrupted. Analysis of alpha 1 (IV) and alpha 2 (IV) chains indicates the residues in the three Gly-X-Y triplets preceding or following interruptions differ statistically from the rest of the cha... |
7760798 | Inhibition of chloroplast DNA recombination and repair by dominant negative mutants of Escherichia coli RecA. | The occurrence of homologous DNA recombination in chloroplasts is well documented, but little is known about the molecular mechanisms involved or their biological significance. The endosymbiotic origin of plastids and the recent finding of an Arabidopsis nuclear gene, encoding a chloroplast-localized protein homologous... |
7760792 | Site-specific initiation of DNA replication in Xenopus egg extract requires nuclear structure. | Previous studies have shown that Xenopus egg extract can initiate DNA replication in purified DNA molecules once the DNA is organized into a pseudonucleus. DNA replication under these conditions is independent of DNA sequence and begins at many sites distributed randomly throughout the molecules. In contrast, DNA repli... |
7759596 | TLC of p-nitroanilines and their analogues with cyclodextrins in the mobile phase. | The addition of alpha-, beta-, gamma-, and hydroxypropyl-beta-cyclodextrins to aqueous mobile phases can be used to enhance the migration of p-nitroanilines and their analogues on thin-layer chromatography. Urea, which is used to solubilize the cyclodextrins in aqueous solutions, is also found to increase the migration... |
7754947 | Abnormalities in elastic fibers and other connective-tissue components of floppy mitral valve. | Histologic, immunohistochemical, and ultrastructural studies were performed on 12 floppy mitral valves, 4 mitral valves showing focal myxomatous changes without prolapse, and 3 normal mitral valves. All floppy mitral valves were thickened by deposits of proteoglycans and also showed diverse structural abnormalities in ... |
7745754 | Immunization with viruslike particles from cottontail rabbit papillomavirus (CRPV) can protect against experimental CRPV infection. | We tested the ability of vaccination with virus-like particles (VLPs) to protect domestic rabbits against papillomas induced by the cottontail rabbit papillomavirus (CRPV). A recombinant baculovirus system that expressed only the L1 major papillomavirus structural protein or L1 plus the minor L2 protein was used in ins... |
7745749 | Brain- and intestine-specific variants of reovirus serotype 3 strain dearing are selected during chronic infection of severe combined immunodeficient mice. | Mutants of mammalian reoviruses, enteric double-stranded-RNA-containing viruses that spread systemically after primary replication in intestinal tissue, have been extensively studied as models of viral pathogenesis. While reovirus serotype 3 strain Dearing (T3D) causes acute encephalitis in newborn mice, adult severe c... |
7745733 | The rubella virus RNA binding activity of human calreticulin is localized to the N-terminal domain. | The rubella virus RNA 3' cis-acting element, which is essential for viral negative-strand RNA synthesis, is specifically bound by autophosphorylated calreticulin. Autophosphorylation in recombinant human calreticulin occurs on serine and threonine residues. The RNA-binding and autophosphorylation activities were locali... |
7745720 | Growth of macrophage-tropic and primary human immunodeficiency virus type 1 (HIV-1) isolates in a unique CD4+ T-cell clone (PM1): failure to downregulate CD4 and to interfere with cell-line-tropic HIV-1. | Human immunodeficiency virus type 1 (HIV-1) isolates derived directly from clinical samples are usually unable to grow in cytokine-independent continuous cell lines, thus hindering the study of their biological features and their sensitivity to humoral and cellular protective immunity. To overcome these limitations, we... |
7745708 | RNA-protein interactions directed by the 3' end of human rhinovirus genomic RNA. | The replication of a picornavirus genomic RNA is a template-specific process involving the recognition of viral RNAs as target replication templates for the membrane-bound viral replication initiation complex. The virus-encoded RNA-dependent RNA polymerase, 3Dpol, is a major component of the replication complex; howeve... |
7707543 | Membrane vesiculation function and exocytosis of wild-type and mutant matrix proteins of vesicular stomatitis virus. | Transfection of mammalian CV1 cells with a recombinant M-gene pTM1 plasmid, driven by vaccinia virus-expressed phage T7 polymerase, resulted in the expression of matrix (M) protein, which is progressively released from the exterior surface of the transfected-cell plasma membrane. Exocytosis of M protein begins 2 to 4 h... |
7707534 | Mutations in the epsilon sequences of human hepatitis B virus affect both RNA encapsidation and reverse transcription. | Hepadnaviruses replicate by reverse transcription of an RNA intermediate within subviral core particles in the cytoplasm of infected hepatocytes. Recognition of the epsilon encapsidation signal located on the 5' end of the pregenomic RNA by the viral polymerase occurs early in core particle assembly. The epsilon sequen... |
7707526 | Replication of Epstein-Barr virus oriLyt: lack of a dedicated virally encoded origin-binding protein and dependence on Zta in cotransfection assays. | Using a transient replication assay in which cosmid DNAs were cotransfected into Vero cells, we had previously demonstrated that oriLyt replication required six Epstein-Barr virus (EBV)-encoded replication genes. No oriLyt origin-binding protein was identified in this study, but oriLyt replication in the cotransfection... |
7707502 | Adaptation of human immunodeficiency virus type 1 to cells expressing a binding-deficient CD4 mutant (lysine 46 to aspartic acid). | Human immunodeficiency virus (HIV-1) was adapted to replicate efficiently in cells expressing an altered form of the CD4 viral receptor. The mutant CD4 (46 K/D) contained a single amino acid change (lysine 46 to aspartic acid) in the CDR2 loop of domain 1, which results in a 15-fold reduction in affinity for the viral ... |
7707501 | Constitutive activation of a variant of the env-mpl oncogene product by disulfide-linked homodimerization. | The myeloproliferative leukemia retrovirus (MPLV) has the v-mpl cellular sequences transduced in frame with the deleted and rearranged Friend murine leukemia virus env gene. The resulting env-mpl fusion oncogene is responsible for an acute myeloproliferative disorder induced in mice by MPLV. v-mpl is a truncated form o... |
11607546 | A multimer model for P680, the primary electron donor of photosystem II. | We consider a model of the photosystem II (PS II) reaction center in which its spectral properties result from weak (approximately 100 cm-1) excitonic interactions between the majority of reaction center chlorins. Such a model is consistent with a structure similar to that of the reaction center of purple bacteria but ... |
24214225 | False positives and the detection of cyclodextrin inclusion complexes by electrospray mass spectrometry. | The results of previous works that have claimed to detect cyclodextrin inclusion complexes via the "soft" ionization technique of electrospray ionization mass spectrometry are revisited. A more extensive study of cyclodextrin mixtures with amino acids and small peptides demonstrates that amino acid and peptide "complex... |
9383433 | Molecular recognition of the inhibitor AG-1343 by HIV-1 protease: conformationally flexible docking by evolutionary programming. | <h4>Background</h4>An important prerequisite for computational structure-based drug design is prediction of the structures of ligand-protein complexes that have not yet been experimentally determined by X-ray crystallography or NMR. For this task, docking of rigid ligands is inadequate because it assumes knowledge of t... |
8586614 | Differential scanning calorimetric studies on the domain structure of Aspergillus glucoamylase. | Thermal unfolding of two forms of Aspergillus niger glucoamylase was observed by adiabatic differential scanning calorimetry (DSC) at pH 7. The DSC traces of the larger form of the enzyme, G1, and the shorter form which lacks the C-terminal starch-binding domain of G1, G2, could be resolved by assuming two-state unfold... |
8573354 | Multiple molecular recognition properties of the lipocalin protein family. | The lipocalins, a diverse family of small extracellular ligand binding proteins, display a remarkable range of different molecular recognition properties. While their binding of small hydrophobic molecules, and to a lesser extent their binding to cell surface receptors, is well known, it is shown here that formation of... |
8573353 | Changes in kinetic properties of oxytocin receptors in longitudinal muscle membranes of rat uterus during gestation. | Receptors of oxytocin were found to occur in the membrane fraction obtained from longitudinal muscle of pregnant rat uterus. The affinity of the membrane receptor for oxytocin increased through an increase in the association rate and a decrease in the dissociation rate during gestation. The membrane oxytocin receptor c... |
8573352 | Detection and side-chain specificity of IgE antibodies to flucloxacillin in allergic subjects. | Unlike studies on the antigenicity of penicillins in laboratory animals, limited information is available on the allergenicity of penicillins in man, especially with regard to fine structural allergenic differences between the many different penicillins. Inconsistent with the earlier conclusions of others, our studies ... |
8552064 | [Structure-activity relationships in multienzyme complexes]. | Structures and molecular kinetic models of function of 2-oxo acid dehydrogenase complexes were analyzed. It was suggested that identical protein subunits in the multienzyme complexes as in the structure capable of self-assembly have identical contacts with the neighbors and identical environment. By sharing the enzyme ... |
7588562 | Cyclodextrin modified micellar electrokinetic chromatography for the chiral direct resolution of (+), (-)-trans-1,2-dihydrodiol metabolite of chrysene in vitro activated by rat liver microsome S9 fraction. | A gamma-cyclodextrin (gamma-CD) modified electrokinetic micellar capillary chromatography (MEKC) method was used for the enantiomer separation of a racemic trans-1,2-dihydro-1,2-dihydroxy-chrysene (chry-trans-1,2-diOH) mixture. The chiral resolution was strongly influenced by several important parameters: surfactant co... |
7553973 | New oral dosage form for elderly patients. II. Release behavior of benfotiamine from silk fibroin gel. | Silk fibroin gel (SFG) containing benfotiamine (BTMP) was prepared. The release behavior of BTMP from SFG was studied as a function of silk fibroin (SF) content and glycerol content, and the influence of the existence of beta-cyclodextrin (beta-CD) on the physicochemical properties of SFG were investigated. The release... |
7566347 | Alzheimer neurofibrillary lesions: molecular nature and potential roles of different components. | Neurofibrillary lesions found in Alzheimer disease (AD) are known to react with antibodies raised against different molecules. At least 20 components have been detected in neurofibrillary tangles. These components can be roughly categorized into five groups, which include structural proteins, kinases and other cytosoli... |
7556511 | Semiconduction of proteins as an attribute of the living state: the ideas of Albert Szent-Györgyi revisited in light of the recent knowledge regarding oxygen free radicals. | Oxyradicals have been considered as harmful byproducts causing molecular damage during aging. However, evidence is accumulating to show that the actual situation is more complex: the living state implicitly involves the production of oxyradicals. (1) Blast type cells produce much less oxyradicals than the differentiate... |
7556031 | Tinkering with the tinkerer: pollution versus evolution. | Pollutants can act as powerful selective forces by altering genetic variability, its intergenerational transfer, and the size, functional viability, adaptability, and survival of future generations. It is at the level of the cell and the individual that meiosis occurs, that genetic diversity is maintained, and behavior... |
8542503 | Kupffer cells in multiple organ failure--their activation as revealed by immunohistochemistry for lysozyme, alpha 1-antichymotrypsin, and lectins. | It has been recently suggested that multiple organ failure (MOF) is caused by activation of inflammatory cells and subsequent release soluble factors from these cells. However, morphologic data to support this hypothesis is lacking. Thus, the present study was conducted to evaluate the activation of Kupffer cells in mu... |
7663420 | Lectin-like center in the molecule of alpha-chymotrypsin: formation of complexes with peroxidase and artificially glycosylated alpha-chymotrypsin. | Using the system of reversed micelles of Aerosol OT1 in octane as an instrument revealing the possibility of supramolecular structures formation, we have shown that the native alpha-chymotrypsin can form complexes with glycoproteins. Dimers of the native alpha-chymotrypsin with the artificially glycosylated one and wit... |
7663287 | [The local anesthetic activity of inclusion compounds of pirbentan and trimecaine with beta-cyclodextrin]. | Whether the prolonged action of the topical anesthetics trimecaine and pirbentan can be achieved by using inclusion compounds was studied. beta-Cyclodextrin was used as an agent containing topical anesthetics in its molecule. In in vitro and in vivo experiments, the inclusion compounds trimecaine and pirbentan with bet... |
7658342 | Phase behavior of tyloxapol/Triton X100/water mixtures. | The influence of admixture of Triton X100 to the polymer tyloxapol and the phase behavior of the mixtures in contact with water was investigated by viscometry, polarization microscopy, and X-ray scattering. The viscosity of tyloxapol/Triton X100 mixtures is lower than that of pure tyloxapol. With increasing Triton X100... |
7656878 | Measurement of acidic aerosol species in eastern Europe: implications for air pollution epidemiology. | A large number of studies have indicated associations between particulate air pollution and adverse health outcomes. Wintertime air pollution in particular has been associated with increased mortality. Identification of causal constituents of inhalable particulate matter has been elusive, although one candidate has bee... |
7655305 | A novel method for the amino acid sequence/configuration determination of peptides containing D/L-amino acids utilizing a fluorogenic Edman reagent, 7-N,N-dimethylaminosulphonyl-4-(2,1,3-benzoxadiazolyl)isothiocyanate (DBD-NCS). | A novel method for the amino acid sequence and configuration determination of peptides containing D- or L-amino acids is presented. An enkephalin analogue, [D-Ala2, D-Leu5]enkephalin (Tyr-Ala-Gly-Phe-Leu) was derivatized with a fluorogenic Edman reagent, 7-N,N-dimethylaminosulphonyl-4-(2,1,3-benzoxadiazolyl) isothiocya... |
7655301 | Effect of column temperature and nitrogen flow rate on the separation of cis-permethrinic acid isomers on a (2,3,6-tri-O-methyl)-beta-cyclodextrin coated capillary column. | The separation efficiency of a capillary column coated with (2,3,6-tri-O-methyl)-beta-cyclodextrin was determined at the temperature and flow rate ranges of 80-120 degrees C and 0.3-1.5 mL/min respectively using (+) and (-) cis-permethrinic acid methylesters as test compounds. The dependence of the retention difference... |
7648207 | Conformational change due to esterification of hydroxy groups in erythromycin A and its major metabolite: analysis of these derivatives with different biological properties using NMR and molecular dynamics (MD) data. | A conformational study is performed on the acylated erythromycin and erythralosamine derivatives from comparison between experimental results (NMR) and theoretical calculations by Molecular Dynamics (MD) in attempts to correlate their conformations with their abilities to generate cytochrome P450-nitroso metabolite com... |
7647975 | Characterization of U-97775 as a GABAA receptor ligand of dual functionality in cloned rat GABAA receptor subtypes. | 1. U-97775 (tert-butyl 7-chloro-4,5-dihydro-5-[(1-(3,4,5-trimethyl)piperazino)carbonyl]- imidazo[1,5-a])quinoxaline-3-carboxylate) is a novel GABAA receptor ligand of dual functionality and was characterized for its interactions with cloned rat GABAA receptors expressed in human embryonic kidney cells. 2. The drug prod... |
7632796 | "Cleavable trifunctional" approach to receptor affinity labeling: chemical regeneration of binding to A1-adenosine receptors. | A general approach for reversible affinity labeling of receptors has been developed. The objective is to carry out a series of chemical modifications resulting in a covalently-modified, yet functionally-regenerated, receptor protein that also may contain a reporter group. The ligand recognition site of A1-adenosine rec... |
7629305 | Ultrastructural examination of the targets of serotonin-immunoreactive descending interneurons in the guinea pig small intestine. | Serotonin neurons are descending interneurons in the myenteric plexus of the guinea pig small intestine. Preembedding single- and double-label immunocytochemistries at the ultrastructural level were used to identify the targets of these serotonin interneurons. Serial ultrathin sections were taken through a myenteric ga... |
7625808 | Activities of the triazole SCH 51048 against Coccidioides immitis in vitro and in vivo. | The activity of the novel triazole SCH 51048 was tested against Coccidioides immitis. SCH 51048 inhibited C. immitis in vitro; MICs for 13 isolates ranged from < or = 0.39 to 0.78 micrograms/ml, and minimum fungicidal concentrations ranged from < or = 0.39 to 1.6 micrograms/ml. In vivo, no mice treated with SCH 51048 a... |
7624971 | Functional domains of GABAA receptors. | The transmitter-gated ion channels mediate rapid synaptic transmission, for example, at the neuromuscular junction using acetylcholine and in the CNS using primarily the amino acids glutamate and GABA. GABAA-receptor Cl- channels share sequence homology with a superfamily of these channels including nicotinic acetylcho... |
7615731 | Comparison of phenotypic characteristics, DNA-DNA hybridization results, and results with a commercial rapid biochemical and enzymatic reaction system for identification of viridans group streptococci. | The rapid ID 32 Strep system (bioMérieux, Marcy l'Etoile, France) was evaluated for its ability to identify 21 species of viridans group streptococci; results were compared with DNA-DNA hybridization results and results of conventional physiological tests. A total of 171 strains of the 21 species including 147 clinical... |
7612856 | Sequential assembly of collagen revealed by atomic force microscopy. | Most polymers which comprise biological filaments assemble by two mechanisms: nucleation and elongation or a sequential, stepwise process involving a hierarchy of intermediate species. We report the application of atomic force microscopy (AFM) to the study of the early events in the sequential or stepwise mode of assem... |
7612848 | Antagonistic effects of hydrostatic pressure and osmotic pressure on cytochrome P-450cam spin transition. | The combined effects of hydrostatic pressure and osmotic pressure, generated by polyols, on the spin equilibrium of fenchone-bound cytochrome P-450cam were investigated. Hydrostatic pressure indices a high spin to low spin transition, whereas polyols induce the reversed reaction. Of the four solutes used, glycerol, glu... |
7612833 | Structure and phase behavior of lipid suspensions containing phospholipids with covalently attached poly(ethylene glycol). | Liposomes containing phospholipids with covalently attached poly(ethylene glycol) (PEG-lipids) are being developed for in vivo drug delivery. In this paper we determine the structure and phase behavior of fully hydrated distearoylphosphatidylcholine (DSPC) suspensions containing PEG-lipids composed of distearoylphospha... |
7612827 | Phase diagram of soybean phosphatidylcholine-diacylglycerol-water studied by x-ray diffraction and 31P- and pulsed field gradient 1H-NMR: evidence for reversed micelles in the cubic phase. | The phase equilibria of the system soybean phosphatidylcholine, diacylglycerol, and water has been determined using a combination of classical methods together with x-ray diffraction and NMR techniques. In particular, the extent of the phase regions of the lamellar, the reversed hexagonal, and the cubic phases have bee... |
7612822 | Functional role of a conserved aspartate in the external mouth of voltage-gated potassium channels. | Mutation of the glycines in a conserved Gly-Tyr-Gly-Asp sequence in the P-region of voltage-gated K channels has identified determinants of Na/K selectivity. But the function of the negatively charged Asp is not known because mutations at this position are not tolerated, owing to the fourfold replication of mutations i... |
7612808 | Radial packing, order, and disorder in collagen fibrils. | Collagen fibrils resemble smectic, liquid crystals in being highly ordered axially but relatively disordered laterally. In some connective tissues, x-ray diffraction reveals three-dimensional crystallinity in the molecular packing within fibrils, although the continued presence of diffuse scatter indicates significant ... |
7612807 | Imaging biomolecule arrays by atomic force microscopy. | We describe here a method for constructing ordered molecular arrays and for detecting binding of biomolecules to these arrays using atomic force microscopy (AFM). These arrays simplify the discrimination of surface-bound biomolecules through the spatial control of ligand presentation. First, photolithography is used to... |
7596338 | [Endotoxin eliminating therapy in patients with severe sepsis--direct hemoperfusion using polymyxin B immobilized fiber column]. | <h4>Background and methods</h4>PMX is a blood purifier containing chemically immobilized polymyxin B fiber (PMX-F). To evaluate its effectiveness on the severe septic human, direct hemoperfusion (DHP) using a PMX-F was performed for 2 hours. The changes in various circulatory parameters, symptoms of septic shock, and b... |
7797119 | South Asian and European colitics show characteristic differences in colonic mucus glycoprotein type and turnover. | South Asians in Britain have a high incidence of ulcerative colitis and a low incidence of colorectal cancer. The pattern of mucus production in 12 South Asian and 16 European colitics and a control group of 19 South Asians was studied. Three types of mucin were identified after organ culture of colonic biopsy specimen... |
7787301 | Comparison of o-phthalaldehyde modification of alpha-amylases from porcine pancreas and Bacillus subtilis with Taka-amylase A. | A fluorescent reagent, o-phthalaldehyde (OPA), competitively inhibited porcine pancreatic alpha-amylase (PPA) with Ki values of 0.7-0.9 mM, while alpha-amylase from Bacillus subtilis (BS) was uncompetitively inhibited, with Ki values of 5.8-7.6 mM. In both cases, OPA gave a time-dependent irreversible inactivation, whe... |
7786289 | A radical approach to enzyme catalysis. | Free radicals are generally perceived as highly reactive species which are harmful to biological systems. There are, however, a number of enzymes that use carbon-based radicals to catalyse a variety of important and unusual reactions. The most prominent example is ribonucleotide reductase, an enzyme which is crucial fo... |
7784211 | Tandem repeats of the 5' non-transcribed spacer of Tetrahymena rDNA function as high copy number autonomous replicons in the macronucleus but do not prevent rRNA gene dosage regulation. | The rRNA genes in the somatic macronucleus of Tetrahymena thermophila are normally on 21 kb linear palindromic molecules (rDNA). We examined the effect on rRNA gene dosage of transforming T.thermophila macronuclei with plasmid constructs containing a pair of tandemly repeated rDNA replication origin regions unlinked to... |
7784206 | Direct measurement via phage titre of the dissociation constants in solution of fusion phage-substrate complexes. | Studies of interactions between filamentous fusion phage particles and protein or nucleic acid molecules have gained increasing importance with recent successes of screening techniques based upon random phage display libraries (biopanning). Since a number of different phage are usually obtained by biopanning, it is use... |
7780664 | Yeast artificial chromosome cloning of the beta-catenin locus on human chromosome 3p21-22. | beta-Catenin has emerged as an important component of the adherens junctions between epithelial cells. As a result of studies of its interaction with the APC gene product, it has been implicated in the development of colorectal cancer. alpha-Catenin, beta-catenin, E-cadherin and APC appear to mediate contact inhibition... |
7780663 | General characteristics of the polytene chromosome from ovarian pseudonurse cells of the Drosophila melanogaster otu11 and fs(2)B mutants. | Polytene chromosomes of good cytological quality from pseudonurse cells (PNCs) of fs(2)B and otu11 mutants were obtained, photomaps for otu11 mutants were constructed and the general characteristics of polytene chromosomes from salivary glands (SGs) and PNCs were compared. Three conditions were found to improve the cyt... |
7780662 | Synaptonemal complex analysis in spermatocytes and oocytes of rainbow trout, Oncorhynchus mykiss (Pisces, Salmonidae): the process of autosome and sex chromosome synapsis. | The surface-spreading synaptonemal complex (SC) technique was employed to analyze spermatocytes and oocytes of rainbow trout in order to visualize the process of autosome and sex chromosome synapsis in this species. The structure of lateral elements (LEs) of the SC and the chromosome synapsis process at the stages of l... |
7780661 | Identification of highly conserved loci by genome painting. | Fluorescence in situ hybridization was used to identify patterns of DNA similarity among the genomes of several rodent taxa. Total genomic or Cot-1 DNAs were used as hybridization probes against metaphase preparations across different taxonomic levels, including three species of Microtus (suborder Sciurognathi), three ... |
7780660 | The developmental stage of inactivation of rye origin rRNA genes in the embryo and endosperm of wheat x rye F1 hybrids. | To identify the developmental stage during which the preferential inactivation of rRNA genes from the rye parent occurs in wheat x rye hybrids, nucleolar activity was evaluated in the embryo and endosperm of developing seeds of the hybrids. The hybrids were obtained from crosses of euploid and aneuploid lines of hexapl... |
7780659 | Do chiasmata disappear? An examination of whether closely spaced chiasmata are liable to reduction or loss. | The questions of whether closely spaced crossovers could be misidentified as single chiasmata or could cancel out each other and whether exchange could occur without chiasma formation were examined in Locusta migratoria. Monochiasmate bivalents that showed differential sister chromatid staining following bromodeoxyurid... |
7540096 | RNA metabolism in situ at the 93D heat shock locus in polytene nuclei of Drosophila melanogaster after various treatments. | Quantitative in situ hybridization to RNA on polytene chromosome spreads, using the 93D exon-, intron- and repeat-specific 35S-labeled antisense RNA probes, revealed treatment- (heat shock, benzamide, colchicine, heat shock followed by benzamide and heat shock in the presence of colchicine) specific differences in the ... |
7780658 | Karyotype evolution in holocentric chromosomes of three related species of triatomines (Hemiptera-Reduviidae). | C-banded karyotypes, DNA content and the male meiiotic process of Triatoma platensis and Triatoma delpontei are compared with those of Triatoma infestans, the main vector of Chagas disease in South America. These three species present the same diploid chromosome number 2n = 22 (20 autosomes + XX male/XY female). They a... |
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