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1924326 | A soluble, single-chain T-cell receptor fragment endowed with antigen-combining properties. | A strategy for the production of small, soluble, single-chain T-cell receptor (scTCR) fragments that carry an intact TCR antigen-combining site is presented. The rationale is based on structural similarity between TCR and antibody molecules and use of computer modeling methods to derive a model structure of a human scT... |
1717976 | Signal transduction by integrins: increased protein tyrosine phosphorylation caused by clustering of beta 1 integrins. | The integrin family of cell adhesion receptors mediates many of the interactions between cells and the extracellular matrix. Because the extracellular matrix has profound influences on cell behavior, it seems likely that integrins transduce biochemical signals across the cell membrane. The nature of these putative sign... |
1681509 | Codon choice and potential complementarity between mRNA downstream of the initiation codon and bases 1471-1480 in 16S ribosomal RNA affects expression of glnS. | A cis-acting expression mutation, GAG to GAA, in the third codon of the glnS gene is analyzed. Both codons code for glutamic acid but the mutation is known to increase gene expression by four fold. We show that the mutation has an effect only if it is located in the beginning of a gene but not if located internally. Da... |
1922033 | Activation of skeletal alpha-actin gene transcription: the cooperative formation of serum response factor-binding complexes over positive cis-acting promoter serum response elements displaces a negative-acting nuclear factor enriched in replicating myoblasts and nonmyogenic cells. | Three upstream CBAR cis-acting promoter elements, containing the inner core CC(A/T)6GG of the serum response element (SRE), are required for myogenic cell type-restricted expression of the avian skeletal alpha-actin gene (K.L. Chow and R.J. Schwartz, Mol. Cell. Biol. 10:528-538, 1990). These actin SRE elements display ... |
1922026 | Thyroid-specific enhancer-binding protein (T/EBP): cDNA cloning, functional characterization, and structural identity with thyroid transcription factor TTF-1. | A cDNA clone encoding a thyroid-specific enhancer-binding protein (T/EBP) was isolated from a rat thyroid-derived FRTL-5 cell lambda gt 11 expression library, using a double-stranded oligonucleotide probe. This oligonucleotide was previously demonstrated to have the strongest binding affinity among three cis-acting DNA... |
1920121 | Behavioral effects of A1- and A2-selective adenosine agonists and antagonists: evidence for synergism and antagonism. | The locomotor effects in mice of selective A1 and A2 adenosine agonists, antagonists and combinations of agonists were investigated using a computerized activity monitor. The A2-selective agonist 2-[(2-aminoethylamino)carbonylethylphenylethylamino[-5'-N- ethylcarboxamidoadenosine (APEC), an amine derivative of 2-(carbo... |
1717482 | Nebulin as a length regulator of thin filaments of vertebrate skeletal muscles: correlation of thin filament length, nebulin size, and epitope profile. | Nebulin, a family of giant proteins with size-variants from 600 to 900 kD in various skeletal muscles, have been proposed to constitute a set of inextensible filaments anchored at the Z line (Wang, K., and J. Wright. 1988. J. Cell Biol. 107:2199-2212). This newly discovered filament of the skeletal muscle sarcomere is ... |
1833383 | Frameshift mutations in the bacteriophage Mu repressor gene can confer a trans-dominant virulent phenotype to the phage. | Virulent mutations in the bacteriophage Mu repressor gene were isolated and characterized. Recombination and DNA sequence analysis have revealed that virulence is due to unusual frameshift mutations which change several C-terminal amino acids. The vir mutations are in the same repressor region as the sts amber mutation... |
1680848 | Involvement of GroEL in nif gene regulation and nitrogenase assembly. | Several approaches were used to study the role of GroEL, the prototype chaperonin, in the nitrogen fixation (nif) system. An Escherichia coli groEL mutant transformed with the Klebsiella pneumoniae nif gene cluster accumulated very low to nondetectable levels of nitrogenase components compared with the isogenic wild-ty... |
1717435 | Dissolution and immunochemical analysis of the sheath of the archaeobacterium Methanospirillum hungatei GP1. | The sheath of Methanospirillum hungatei GP1 was degraded by three dissolution techniques, which produced a range of soluble products. By using 0.05 M L-arginine buffer (pH 12.6) at 90 degrees C for 10 min, 74% (dry weight) of the sheath was dissolved; however, the solubilized polypeptides were extensively degraded. Tre... |
1917847 | Analysis of the active center of Bacillus stearothermophilus neopullulanase. | The active center of the neopullulanase from Bacillus stearothermophilus was analyzed by means of site-directed mutagenesis. The amino acid residues located in the active center of the neopullulanase were tentatively identified according to a molecular model of Taka-amylase A and homology analysis of the amino acid seq... |
1655697 | Nucleotide sequence and genetic analysis of a 13.1-kilobase-pair Pseudomonas denitrificans DNA fragment containing five cob genes and identification of structural genes encoding Cob(I)alamin adenosyltransferase, cobyric acid synthase, and bifunctional cobinamide kinase-cobinamide phosphate guanylyltransferase. | A 13.1-kb DNA fragment carrying Pseudomonas denitrificans cob genes has been sequenced. The nucleotide sequence and genetic analysis revealed that this fragment contained five different cob genes named cobN to cobQ and cobW. Based on the similarity of NH2-terminal sequences and molecular weights of the purified Cob pro... |
1917840 | Genetic and sequence analyses of a Pseudomonas denitrificans DNA fragment containing two cob genes. | A genetic analysis of a 12-kb DNA fragment containing Pseudomonas denitrificans cob genes was performed by transposon-mediated insertional mutagenesis. The nucleotide sequence and genetic analysis have shown that a 4.8-kb DNA subfragment carried two cob genes (cobS and cobT). Biochemical data concerning the complemente... |
1917839 | Biosynthesis of vitamin B12: stepwise amidation of carboxyl groups b, d, e, and g of cobyrinic acid a,c-diamide is catalyzed by one enzyme in Pseudomonas denitrificans. | The cobalamin biosynthetic pathway enzyme that catalyzes amidation of 5'-deoxy-5'-adenosyl-cobyrinic acid a,c-diamide was purified to homogeneity from extracts of a recombinant strain of Pseudomonas denitrificans by a four-column procedure. The purified protein had an isoelectric point of 5.6 and molecular weights of 9... |
1833380 | A genetic analysis of Xis and FIS interactions with their binding sites in bacteriophage lambda. | The bacteriophage P22-based challenge-phage system was used to study the binding of Xis and FIS to their sites in attP of bacteriophage lambda. Challenge phages were constructed that contained the X1, X2, and F sites within the P22 Pant promoter, which is required for expression of antirepressor. If Xis and FIS bind to... |
1917393 | Angiostatic steroids potentiated by sulfated cyclodextrins inhibit corneal neovascularization. | It is known that hydrocortisone can be converted to a potent angiogenesis inhibitor by coadministration with heparin or with a sulfated cyclodextrin. The activity of tetrahydrocortisol-S, a purely angiostatic corticosteroid, can be potentiated by beta-cyclodextrin tetradecasulfate as shown in this study. This drug "pai... |
1916105 | Collagen family of proteins. | Collagen molecules are structural macro-molecules of the extracellular matrix that include in their structure one or several domains that have a characteristic triple helical conformation. They have been classified by types that define distinct sets of polypeptide chains that can form homo- and heterotrimeric assemblie... |
1915365 | Sequence-specific 1H-NMR assignments and secondary structure of the lipoyl domain of the Bacillus stearothermophilus pyruvate dehydrogenase multienzyme complex. | The lipoyl domain (residues 1-85) of the lipoate-acetyltransferase polypeptide chain of the pyruvate dehydrogenase multienzyme complex of Bacillus stearothermophilus has been subjected to detailed structural analysis by means of two-dimensional (2D) 1H-NMR spectroscopy at 400 MHz. Sequence-specific proton resonance ass... |
1915260 | Electrostatic destabilization of the cytochrome b6f complex in the thylakoid membrane. | Three of the membrane-spanning polypeptides of the chloroplast cytochrome (cyt) b6f complex were sequentially released from the thylakoid membrane, in the order cyt b6, suIV and Rieske iron-sulfur protein, as the pH was increased from 10 to 12, a protocol usually employed to remove peripheral proteins from membranes. T... |
1655402 | A glycosylphosphatidylinositol protein anchor from procyclic stage Trypanosoma brucei: lipid structure and biosynthesis. | Cells of the insect (procyclic) stage of the life cycle of the African trypanosome, Trypanosoma brucei, express an abundant stage-specific glycosylated phosphatidylinositol (GPI) anchored glycoprotein, the procyclic acidic repetitive protein (PARP). The anchor is insensitive to the action of bacterial phosphatidylinosi... |
1911215 | Phorbol ester and bryostatin effects on growth and the expression of oestrogen responsive and TGF-beta 1 genes in breast tumour cells. | The phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA) (10 nM) produce a marked reduction in the growth, measured by thymidine uptake, of MCF-7 cells in full growth medium, but had only a small effect on MDA-MB-231 and T47D cells. Bryostatin alone also inhibited growth but to a lesser extent than seen with TPA. ... |
1895386 | Mutational analysis of N-linked glycosylation sites of Friend murine leukemia virus envelope protein. | The roles played by the N-linked glycans of the Friend murine leukemia virus envelope proteins were investigated by site-specific mutagenesis. The surface protein gp70 has eight potential attachment sites for N-linked glycan; each signal asparagine was converted to aspartate, and mutant viruses were tested for the abil... |
1832664 | Expression of Fc gamma RIII on HeLa 229 cells: possible effect on in vitro neutralization of Chlamydia trachomatis. | The neutralizing activities of a murine immunoglobulin G3 (IgG3) monoclonal antibody specific for the major outer membrane protein of Chlamydia trachomatis and its monovalent Fab fragments were studied by using Syrian hamster kidney (HaK) cells and human epithelial (HeLa 229) cells. The intact IgG3 antibody was neutral... |
1680106 | Proteus mirabilis flagella and MR/P fimbriae: isolation, purification, N-terminal analysis, and serum antibody response following experimental urinary tract infection. | Urinary tract infection with Proteus mirabilis may lead to serious complications, including cystitis, acute pyelonephritis, fever, bacteremia, and death. In addition to the production of hemolysin and the enzyme urease, fimbriae and flagellum-mediated motility have been postulated as virulence factors for this species.... |
1894351 | Specific T-cell response to a Pneumocystis carinii surface glycoprotein (gp120) after immunization and natural infection. | T cells have been shown to be important in recovery from Pneumocystis carinii pneumonitis, although no specific antigen of P. carinii has been defined as containing T-cell epitopes. P. carinii has an abundant mannosylated surface glycoprotein of approximately 120 kDa (gp120) which induces a prominent host antibody resp... |
1908555 | A codon change in beta-tubulin which drastically affects microtubule structure in Drosophila melanogaster fails to produce a significant phenotype in Saccharomyces cerevisiae. | The relative uniformity of microtubule ultrastructure in almost all eukaryotic cells is thought to be a consequence of the conserved elements of tubulin sequence. In support of this idea, a mutation in a beta-tubulin gene of Drosophila melanogaster, occurring at a highly conserved position, produces U-shaped microtubul... |
1715022 | Antifungal properties of the immunosuppressant FK-506: identification of an FK-506-responsive yeast gene distinct from FKB1. | FK-506 is a novel and potent antagonist of T-cell activation and an inhibitor of fungal growth. Its immunosuppressive activity can be antagonized by the structurally related antibiotic rapamycin, and both compounds interact with cytoplasmic FK-506-binding proteins (FKBPs) in T cells and yeast cells. In this paper, we s... |
1874787 | EA-1, a novel adhesion molecule involved in the homing of progenitor T lymphocytes to the thymus. | The mouse progenitor T lymphocyte (pro-T) cell line FTF1 binds in vitro to thymus blood vessels, the thymic capsule, and liver from newborn mice. A mAb, EA-1, raised against an embryonic mouse endothelial cell line, blocked adhesion. The antibody also interfered with pro-T cell adhesion to a thymus-derived mouse endoth... |
1871977 | Functional domains of HIV-1 gag-polyprotein expressed in baculovirus-infected cells. | Seven recombinants of AcNPV harboring various forms of complete or truncated gag gene from HIV-1 were constructed to determine which functional domains of the gag polyprotein are implicated in its self-assembly and cellular localization. The p6 carboxy-terminal portion of the p15 NCgag domain appeared to be dispensable... |
1870213 | Cytopathic variants of an attenuated isolate of human immunodeficiency virus type 2 exhibit increased affinity for CD4. | Naturally occurring isolates of human immunodeficiency virus (HIV) have been described which are deficient in their ability to fuse with and kill CD4+ target cells. Although the molecular basis for their attenuation has not yet been defined, several lines of evidence point toward the viral envelope gene as a key determ... |
1651418 | Nuclear assembly of polyomavirus capsids in insect cells expressing the major capsid protein VP1. | Polyomavirus normally assembles in the nucleus of infected mouse cells. Sf9 insect cells expressing the polyomavirus major capsid protein VP1 were examined by electron microscopy. Capsidlike particles of apparently uniform size were found in the nucleus. Immunogold electron microscopy demonstrated abundant VP1 in the c... |
1714520 | Epitope mapping of two immunodominant domains of gp41, the transmembrane protein of human immunodeficiency virus type 1, using ten human monoclonal antibodies. | Immunogenic regions of the gp41 transmembrane protein of human immunodeficiency virus type 1 (HIV-1) were previously mapped by examining polyclonal sera from HIV-infected patients and rodent polyclonal and monoclonal antibodies (MAbs) to peptides of gp41. To define the epitopes within these regions to which infected hu... |
1870202 | Recombinant CD4-selected human immunodeficiency virus type 1 variants with reduced gp120 affinity for CD4 and increased cell fusion capacity. | Variants of molecularly cloned human immunodeficiency virus type 1 (HIV-1) were analyzed following selection for the ability to replicate after exposure to soluble, recombinant CD4 protein (rCD4). Two variants, 4/1 and 16/2, show 8-fold and 16-fold reduced sensitivity to rCD4 neutralization yet remain as sensitive as t... |
1870199 | RGD-dependent entry of coxsackievirus A9 into host cells and its bypass after cleavage of VP1 protein by intestinal proteases. | The recently reported nucleotide sequence of coxsackievirus A9 (CAV-9) showed that unlike other enteroviruses, CAV-9 has an insertion of about 17 amino acids at the C-terminal end of VP1 (K. H. Chang, P. Auvinen, T. Hyypiä, and G. Stanway, J. Gen. Virol. 70:3269-3280, 1989). This sequence includes the RGD (arginine-gly... |
1870196 | A single point mutation activates the Moloney murine leukemia virus long terminal repeat in embryonal stem cells. | The expression of Moloney murine leukemia virus (Mo-MuLV) and Mo-MuLV-derived vectors is restricted in undifferentiated mouse embryonal carcinoma and embryonal stem (ES) cells. We have previously described the isolation of retroviral mutants with host range properties expanded to embryonal cell lines. One of these muta... |
1788164 | A redox-based chemical delivery system that enhances estradiol distribution to the brain: disposition studies in the rat. | The disposition of a chemical delivery system for estradiol (E2-CDS) which is based on a redox dihydropyridine-pyridinium salt conversion was investigated in rats. Tissue and plasma concentrations of E2-CDS and the oxidized metabolite (E2-Q+) were evaluated at times ranging from 1 to 14 days after intravenous administr... |
1788160 | Cyclodextrin sulfates: characterization as polydisperse and amorphous mixtures. | Alpha- and beta-cyclodextrins and their hydroxypropyl derivatives were converted by the reaction with chlorosulfonic acid in pyridine to the corresponding sulfates. Cyclodextrin sulfates were shown by fast-atom bombardment mass spectrometry (negative ion mode, triethanolamine matrix) to be mixtures with nearly symmetri... |
1786511 | Inositol 1,4,5-triphosphate-stimulated calcium release from permeabilized cerebellar granule cells. | 1. Muscarinic cholinoceptor stimulation of phosphoinositide hydrolysis in rat cultured cerebellar granule cells results in a rapid, transient accumulation of inositol 1,4,5-trisphosphate (Ins(1,4,5)P3), which has been implicated in the release of non-mitochondrial intracellular Ca2+ stores. In the present study, the re... |
1784634 | Regioselective photoreduction of zinc(II) porphyrins to give chlorins. | The ascorbic acid/organic base photoreduction of zinc(II) porphyrins was investigated. It was established that certain substituents can direct the photoreduction to the site of the macrocycle to which they are attached. For example, zinc(II) vinylporphyrins (8, 12, 16, 20) are photoreduced with cis stereochemistry on t... |
1752239 | The electrophoretic properties of a DNA cube and its substructure catenanes. | Electrophoretic properties have been measured for a DNA molecule whose helix axes have the connectivity of a cube. This molecule is a topologically bonded complex of six cyclic 80-mer molecules, in which each cycle corresponds to a face of the cube. Each cyclic molecule is doubly catenated to each of its four neighbors... |
1720798 | The distribution of myelinated nerve fibers in the mature opossum esophagus. | Myelination of nerve fibers could be important in establishing normal esophageal peristalsis. We therefore examined the general distribution and the age of appearance of myelinated nerve fibers in the smooth-muscle part of the esophagus of the American opossum. Tissues stained with thionein and Sudan black B were exami... |
1660308 | Nerve growth factor induces the association of a 130-Kd phosphoprotein with its receptor in PC-12 pheochromocytoma cells. | To explore the molecular mechanisms of nerve growth factor (NGF) action, we have attempted to identify proteins that immunoprecipitate with the NGF receptor. An anti-NGF receptor antibody was developed that immunoprecipitated the 75-Kd receptor in PC-12 cells. In [35S]methionine-labeled cells lysed with nonionic deterg... |
1955819 | Effects of schedule of reinforcement on a pentobarbital discrimination in rats. | The purpose of this study was to determine the effects of the schedule of reinforcement on a pentobarbital discrimination in rats. Five rats were trained to discriminate 10 mg/kg pentobarbital from saline under a multiple fixed-interval 180-s fixed-ratio 20 schedule of reinforcement. During both saline and pentobarbita... |
1944211 | [Immunological assessment of the pathogenesis of septic-MOF: relationship between complement activation and changes in neutrophil functions]. | We investigated the pathogenesis of septic-MOF through the relationship between changes in neutrophil functions and degree of complement activation. The patients' neutrophils exhibited enhanced adherence to HUVEC, suppressed chemotaxis toward C5a, enhanced production of oxygen radicals and lysosomal enzymes. These chan... |
1944210 | [Clinico-experimental analysis of backgrounds of the severe surgical infections]. | The purpose of this study was to analyse the clinical course of 410 patients of severe surgical infections (primary 251, postoperative 159) during recent 5 years and to evaluate the important background factors which make these patients serious. As a result, the following patients such as, (1) who have refractory prima... |
1682792 | Bacillus sphaericus as a mosquito pathogen: properties of the organism and its toxins. | In the course of sporulation, Bacillus sphaericus produces an inclusion body which is toxic to a variety of mosquito larvae. In this review we discuss the general biology of this species and concentrate on the genetics and physiology of toxin production and its processing in the midgut of the larval host. The larvicide... |
1943994 | Genetic competence in Bacillus subtilis. | Genetic competence may be defined as a physiological state enabling a bacterial culture to bind and take up high-molecular-weight exogenous DNA (transformation). In Bacillus subtilis, competence develops postexponentially and only in certain media. In addition, only a minority of the cells in a competent culture become... |
1932556 | Effect of bile salts on monolayer curvature of a phosphatidylethanolamine/water model membrane system. | A partial phase diagram of the ternary system dioleoylphosphatidylethanolamine (DOPE)/sodium cholate/water has been determined using 31P Nuclear Magnetic Resonance (NMR) spectroscopy. In the absence of cholate, it is well known that the DOPE/water system forms a reversed hexagonal (HII) phase. We have found that additi... |
1718469 | Mutations affecting agonist sensitivity of the nicotinic acetylcholine receptor. | The nicotinic acetylcholine receptor (AChR) is a pentameric transmembrane protein (alpha 2 beta gamma delta) that binds the neurotransmitter acetylcholine (ACh) and transduces this binding into the opening of a cation selective channel. The agonist, competitive antagonist, and snake toxin binding functions of the AChR ... |
1656992 | Xanthine oxidase-catalyzed reduction of estrogen quinones to semiquinones and hydroquinones. | Metabolic redox cycling between the stilbene estrogen diethylstilbestrol (DES) and diethylstilbestrol-4',4"-quinone (DES Q) has been demonstrated previously. The xanthine and xanthine oxidase-catalyzed reduction of estrogen quinone has been studied in this work to understand the role of metabolic redox cycling in estro... |
1656385 | Interaction of the Tn7-encoded transposition protein TnsB with the ends of the transposon. | We have used several high resolution methods to examine the interaction of TnsB, a transposition protein encoded by the bacterial transposon Tn7, with its binding sites at the ends of the transposon. These binding sites lie within the DNA segments that are directly involved in transposition. We show that the binding of... |
1656382 | Purification of the DNA binding domain of herpes simplex virus type 1 immediate-early protein Vmw175 as a homodimer and extensive mutagenesis of its DNA recognition site. | The herpes simplex virus type 1 (HSV-1) Immediate-Early (IE) polypeptide Vmw175 is essential for the activation of transcription from viral early and late promoters. Vmw175 also reduces the activity of its own (IE-3) promoter in transfection assays. Both transactivation and repression mediated by Vmw175 require the int... |
1920405 | Molecular characterization of cuticle and interstitial collagens from worms collected at deep sea hydrothermal vents. | Two different collagens were isolated and characterized from the body walls of the vestimentiferan tube worm Riftia pachyptila and the annelid Alvinella pompejana, both living around hydrothermal vents at a depth of 2600 m. The acid-soluble cuticle collagens consisted of a long triple helix (2.4 microns for Alvinella, ... |
1915863 | Hydrolysis of branched cyclodextrins by a cyclodextrin-hydrolyzing enzyme from Bacillus sphaericus E-244. | The action of a cyclodextrin-hydrolyzing enzyme from Bacillus sphaericus E-244 on branched alpha- and beta-cyclodextrins was investigated. Glucosyl-alpha-cyclodextrin (6-O-alpha-D-glucosylcyclomaltohexaose) and maltosyl-alpha-cyclodextrin (6-O-alpha-D-maltosylcyclomaltohexaose) were hydrolyzed to 6(3)-O-alpha-D-glucosy... |
1915839 | Modification of alpha-amylase from Bacillus licheniformis by the polyaldehyde derived from beta-cyclodextrine and alpha-amylase thermostability. | The cleavage of beta-cyclodextrine by sodium periodate at the seven 2-3 diols of the glucose unit gives rise to the polyaldehyde 1, used to modify alpha-amylase. The reductive modification of alpha-amylase from Bacillus licheniformis reduced the number of reactive lysine groups from 8 to 3.5 per mol of enzyme with an a... |
1898370 | Comparison of the catalytic properties of phospholipase A2 from pancreas and venom using a continuous fluorescence displacement assay. | Phospholipases A2 from pig pancreas and the venoms from bee, Naja naja and Crotalus atrox have been studied by using a new continuous fluorescence displacement assay that utilizes normal phospholipid substrates [Wilton (1990) Biochem. J. 266, 435-439]. With limiting amounts of substrate, the assay demonstrated stoichio... |
1654893 | Electron transfer between horse ferritin and ferrihaemoproteins. | Reactions of reduced horse spleen ferritin with horse and Saccharomyces cerevisiae ferricytochromes c, cow ferricytochrome b5, sperm-whale metmyoglobin and Pseudomonas aeruginosa ferricytochrome c-551 were investigated by u.v.-visible spectrophotometry. In all cases the reduced ferritin reduced the ferrihaemoproteins. ... |
1898328 | Synthesis of a gene for rat liver fatty-acid-binding protein and its expression in Escherichia coli. | A gene coding for rat liver fatty-acid-binding protein (FABP) has been constructed by the single-step ligation of ten synthetic oligonucleotides. The gene has been cloned into the bacterial expression vector pKK223-3. Induction of protein synthesis from this gene results in over expression of an FABP that is indistingu... |
1716880 | Kinetics of the urea-induced dissociation of human plasma alpha 2-macroglobulin as measured by small-angle neutron scattering. | The kinetics of the urea-induced dissociation of human plasma alpha 2-macroglobulin into two half-molecular fragments was investigated at 21.0 degrees C by using small-angle neutron scattering. The relative change in molecular mass that occurs upon dissociation was monitored by recording the forward scattering of neutr... |
1910319 | Affinity labeling of a subsite of Taka-amylase A by the fluorescent reagent o-phthalaldehyde. | A cross-linked modification of Lys residue located at the subsite of the enzyme active site of Taka-amylase A was attained by the use of the fluorescent reagent of o-phthalaldehyde (OPA). The fluorescence and uv absorption at 337 nm derived from the isoindole ring, which was produced by cross-linking through the epsilo... |
1896474 | Gene- and strand-specific repair in vitro: partial purification of a transcription-repair coupling factor. | In eukaryotic and prokaryotic cells, activity transcribed genes and, in some instances, the template strand of these genes have been found to be repaired 2-10 times more rapidly than nontranscribed genes or the coding strand of transcribed genes. We demonstrate here gene- and template strand-specific repair synthesis i... |
1896461 | C-terminal processing of barley alpha-amylase 1 in malt, aleurone protoplasts, and yeast. | C-terminal processing of low pI barley alpha-amylase (AMY1) results in multiple forms in malt, aleurone protoplasts, and transformed yeast. Expression of an AMY1 cDNA in yeast thus leads to four secreted forms with distinct pI values between 4.7 and 5.1 and essentially identical Mr. AMY1-1 and AMY1-2 lacking the C-term... |
1895289 | Design and synthesis of P2-P1'-linked macrocyclic human renin inhibitors. | Using a computer model of the active site of human renin developed at Merck, we designed a series of novel P2-P1'-linked, macrocyclic renin inhibitors 3-10. These unique inhibitors incorporate a transition-state isostere within a 13- or 14-membered ring. The three most active compounds in this family were 13-membered-r... |
1894610 | Chloroplast biogenesis. Detection of monovinyl protochlorophyll(ide) b in plants. | The occurrence of protochlorophyllide b and protochlorophyllide b phytyl ester in green plants is described. The chemical structure of protochlorophyllide b phytyl ester was established by proton nuclear magnetic resonance, fast atom bombardment mass spectroscopic analysis, and chemical derivatization coupled to electr... |
1909894 | Characterization of maize microtubule-associated proteins, one of which is immunologically related to tau. | Microtubule-associated proteins (MAPs) are identified as proteins that copurify with tubulin, promote tubulin assembly, and bind to microtubules in vitro. Higher plant MAPs remain mostly unknown. One example of non-tubulin carrot proteins, which bind to neural microtubules and induce bundling, has been reported so far ... |
1653702 | The role of the internal hydrogen bond network in first-order protein electron transfer between Saccharomyces cerevisiae iso-1-cytochrome c and bovine microsomal cytochrome b5. | An internal water molecule (designated WAT166) is found in iso-1-cytochrome c which is part of a redox-state-dependent hydrogen bond network. The position of this water molecule with respect to the polypeptide fold can be altered or even displaced by site-directed mutagenesis leading to structural perturbations and ass... |
1909324 | The cysP promoter of Salmonella typhimurium: characterization of two binding sites for CysB protein, studies of in vivo transcription initiation, and demonstration of the anti-inducer effects of thiosulfate. | The cysPTWA operons of Escherichia coli and Salmonella typhimurium encode components of periplasmic transport systems for sulfate and thiosulfate and are regulated as part of the cysteine regulons. In vitro transcription initiation from the cysP promoter was shown to require both CysB protein and either O-acetyl-L-seri... |
1885545 | Identification, isolation, and structural studies of extracellular polysaccharides produced by Caulobacter crescentus. | Caulobacters are adherent prosthecate bacteria that are members of bacterial biofouling communities in many environments. Investigation of the cell surface carbohydrates produced by two strains of the freshwater Caulobacter crescentus, CB2A and CB15A, revealed a hitherto undetected extracellular polysaccharide (EPS) or... |
1653211 | Gyrase inhibitors increase the content of knotted DNA species of plasmid pBR322 in Escherichia coli. | Treatment of Escherichia coli cells harboring pBR322 with the DNA gyrase inhibitors oxolinic acid and coumermycin A1 led to an increase in the content of knotted pBR322 molecules. This phenomenon was attributed to inhibition of gyrase-catalyzed unknotting of the plasmid DNA knotted by transcription. |
1679428 | Evidence that Porphyromonas (Bacteroides) gingivalis fimbriae function in adhesion to Actinomyces viscosus. | Porphyromonas (Bacteroides) gingivalis adheres to gram-positive bacteria, such as Actinomyces viscosus, when colonizing the tooth surface. However, little is known of the adhesins responsible for this interaction. A series of experiments were performed to determine whether P. gingivalis fimbriae function in its coadhes... |
1882840 | Sequence and localization of a partial cDNA encoding the human alpha 3 chain of type IV collagen. | A novel type IV collagen, alpha 3(IV), has recently been identified in human and bovine basement membranes. Here we describe the cloning and sequencing of a cDNA encoding 218 residues of the NC1 domain of the human alpha 3(IV) chain. Of interest is the possible role of abnormalities of the alpha 3(IV) chain in Alport s... |
1909031 | Envelope proteins from clinical isolates of human immunodeficiency virus type 1 that are refractory to neutralization by soluble CD4 possess high affinity for the CD4 receptor. | Recent evidence indicates that primary clinical isolates of human immunodeficiency virus type 1 (HIV-1) require significantly more soluble CD4 (sCD4) to block infection than the prototypic laboratory strain HTLV-IIIB. The currently accepted explanation for these observations is that the envelope glycoproteins from prim... |
1881913 | I-TevI, the endonuclease encoded by the mobile td intron, recognizes binding and cleavage domains on its DNA target. | Mobility of the phage T4 td intron depends on activity of an intron-encoded endonuclease (I-TevI), which cleaves a homologous intronless (delta In) target gene. The double-strand break initiates a recombination event that leads to intron transfer. We found previously that I-TevI cleaves td delta In target DNA 23-26 nuc... |
1881905 | Expression of a partially deleted gene of human type II procollagen (COL2A1) in transgenic mice produces a chondrodysplasia. | A minigene version of the human gene for type II procollagen (COL2A1) was prepared that lacked a large central region containing 12 of the 52 exons and therefore 291 of the 1523 codons of the gene. The construct was modeled after sporadic in-frame deletions of collagen genes that cause synthesis of shortened pro alpha ... |
1881884 | The carbohydrate domain of calicheamicin gamma I1 determines its sequence specificity for DNA cleavage. | We have investigated the DNA cleaving properties of calicheamicinone, the synthetic core aglycone of calicheamicin gamma I1, a natural product with extremely potent antitumor activity. Our experiments have shown that the synthetic analog binds and cleaves DNA, albeit without any sequence selectivity and with less effic... |
1679125 | Pontomedullary glutamate receptors mediating locomotion and muscle tone suppression. | Microinjection of NMDA and non-NMDA agonists into the same sites in pontomedullary motor "inhibitory" areas of decerebrate animals produced opposite effects on muscle tone. Microinjection of non-NMDA agonists into peri-locus coeruleus alpha (peri-LC alpha) and nucleus magnocellularis (NMC) suppressed muscle tone, while... |
1652558 | Regulation of leukotriene B4 generation from human polymorphonuclear granulocytes after stimulation with formyl-methionyl-leucyl phenylalanine: effects of pertussis and cholera toxins. | The effects of holotoxins and toxin subunits from Bordetella pertussis and Vibrio cholerae strains on intact and digitonin-permeabilized human polymorphonuclear neutrophils were studied. Our data clearly demonstrate that formyl-methionyl-leucyl-phenylalanine (fMLP)-induced generation of chemotactic active leukotriene B... |
1872807 | Differential expression of the mouse U1a and U1b SnRNA genes is not dependent on sequence differences in the octamer motif. | The mouse U1b SnRNA gene is expressed in only a limited range of cell types, whereas the U1a SnRNA gene is expressed in all cells. These two genes differ in the sequence of the octamer motif, which plays a critical role in SnRNA gene regulation. We show that the U1b octamer binds the octamer-binding protein Oct-1 with ... |
1714564 | Synthesis of RNA containing inosine: analysis of the sequence requirements for the 5' splice site of the Tetrahymena group I intron. | Two protected derivatives of the ribonucleoside inosine have been prepared to serve as building blocks for phosphoramidite-based synthesis of RNA. Two different synthetic routes address the unusual solubility characteristics of inosine and its derivatives. The final products of the different synthetic pathways, 5'-O-(d... |
1714461 | A potential role for the COOH-terminal domain in the lateral packing of type III intermediate filaments. | To identify sites of self-association in type III intermediate filament (IF) proteins, we have taken an "anti-idiotypic antibody" approach. A mAb (anti-Ct), recognizing a similar feature near the end of the rod domain of vimentin, desmin, and peripherin (epsilon site or epsilon epitope), was characterized. Anti-idiotyp... |
1907974 | Reconstitution of GTP-binding Sar1 protein function in ER to Golgi transport. | In the yeast secretory pathway, two genes SEC12 and SAR1, which encode a 70-kD integral membrane protein and a 21-kD GTP-binding protein, respectively, cooperate in protein transport from the ER to the Golgi apparatus. In vivo, the elevation of the SAR1 dosage suppresses temperature sensitivity of the sec12 mutant. In ... |
1714389 | Comparative study of the structure/function relationship of wild-type and structurally modified maltopentaose-producing amylase. | Amylase A-180, which is secreted by a new alkaliphilic organism, isolate 163-26, consists of a single type of polypeptide chain of 186.5 kDa and hydrolyses starch by exo-attack releasing malto-pentaose as preferential product. The structure/function relationship of this unusual starch-degrading enzyme was analysed by i... |
1714243 | Expression of endothelial leukocyte adhesion molecule-1 in septic but not traumatic/hypovolemic shock in the baboon. | Baboons were subjected to septic or traumatic/hypovolemic shock and their tissues were examined for the de novo expression of endothelial leukocyte adhesion molecule 1 (ELAM-1), using immunohistochemical techniques. In animals with septic shock induced with live Escherichia coli, there was widespread expression of ELAM... |
1866601 | Human MHC class I antigens are associated with a 90-kDa cell surface protein. | Human MHC class I proteins are expressed on almost all nucleated cells as a heavy chain (about 45 kDa) non-covalently associated with beta 2-microglobulin (12 kDa). In this report we show that MHC class I (MHC-I) proteins can also be associated with a 90-kDa protein in the cell membrane. Surface-radiolabelled cells wer... |
1650794 | Dissociation and redistribution of Na+,K(+)-ATPase from its surface membrane actin cytoskeletal complex during cellular ATP depletion. | Establishment and maintenance of a polar distribution of Na+,K(+)-ATPase is essential for efficient Na+ reabsorption by proximal tubule cells and is dependent upon the formation of a metabolically stable, detergent-insoluble complex of Na+,K(+)-ATPase with the actin membrane cytoskeleton. The present studies show that ... |
1677770 | Stop codon in the procollagen II gene (COL2A1) in a family with the Stickler syndrome (arthro-ophthalmopathy). | Linkage analysis with restriction fragment length polymorphisms for the gene for type II procollagen (COL2A1) was carried out in a family with the Stickler syndrome, or arthro-ophthalmopathy, an autosomal dominant disorder that affects the eyes, ears, joints, and skeleton. The analysis demonstrated linkage of the disea... |
1907372 | Mutations in 16S rRNA that affect UGA (stop codon)-directed translation termination. | Site-directed mutagenesis was performed on a sequence motif within the 3' major domain of Escherichia coli 16S rRNA shown previously to be important for peptide chain termination. Analysis of stop codon suppression by the various mutants showed an exclusive response to UGA stop signals, which was correlated directly wi... |
1862083 | Reversed siderophores act as antimalarial agents. | We describe here a family of biomimetic iron carriers that display high binding efficiency for ferric ions and favorable permeation properties across erythrocytic membranes. These carriers inhibit in vitro growth of Plasmodium falciparum by scavenging intracellular iron. The chemical features were realized by reproduci... |
1860888 | Macromolecular organization of chicken type X collagen in vitro. | The macromolecular structure of type X collagen in the matrices of primary cultures of chick hypertrophic chondrocytes was initially investigated using immunoelectron microscopy. Type X collagen was observed to assemble into a matlike structure with-in the matrix elaborated by hypertrophic chondrocytes. The process of ... |
1860831 | Transcriptional analysis of the Staphylococcus aureus plasmid pI258 mercury resistance determinant. | Northern blot DNA-RNA hybridization analysis of Staphylococcus aureus cells bearing pI258 showed that upon induction the amount of mer operon transcript present increased 49-fold over that observed in uninduced cells. Maximum induction occurred after 45 min in the presence of 5 microM HgCl2. Two transcripts, 5.0 and 5.... |
1860813 | Genetic evidence for interaction between the CheW and Tsr proteins during chemoreceptor signaling by Escherichia coli. | This study presents two lines of genetic evidence consistent with the premise that CheW, a cytoplasmic component of the chemotactic signaling system of Escherichia coli, interacts directly with Tsr, the membrane-bound serine chemoreceptor. (i) We demonstrated phenotypic suppression between 10 missense mutant CheW prote... |
1677356 | Type 1 fimbriae of Salmonella enteritidis. | Salmonella enteritidis was previously shown to produce fimbriae composed of 14,000-molecular-weight (Mr) fimbrin monomers (J. Feutrier, W. W. Kay, and T. J. Trust, J. Bacteriol. 168:221-227, 1986). Another distinct fimbrial structure, comprising 21,000-Mr fimbrin monomers, has now been identified. These fimbriae are si... |
1830294 | Genetic and immunological analysis of Mycobacterium tuberculosis fibronectin-binding proteins. | Recombinant phage clones, TB1 and TB2, were selected from a Mycobacterium tuberculosis lambda gt11 DNA expression library by screening with a polyclonal antiserum raised against the antigen 85 complex of Mycobacterium bovis BCG. Analysis of recombinant DNA inserts and expressed fusion proteins showed that two new genes... |
1855469 | The effects of a brain-enhanced estradiol delivery system on testosterone and androgen-dependent tissues. I. Dose-response and time-course evaluation. | The primary objective underlying hormone treatment of prostatic adenocarcinoma is to induce an effective androgen deprivation, and high dose estrogen therapy is as effective as surgical castration in abolishing the growth-promoting effects of androgens on prostatic tissue. An estradiol-chemical delivery system (E2-CDS)... |
1830128 | E1A induces phosphorylation of the retinoblastoma protein independently of direct physical association between the E1A and retinoblastoma products. | We have studied the initial effects of adenovirus E1A expression on the retinoblastoma (RB) gene product in normal quiescent cells. Although binding of the E1A products to pRB could, in theory, make pRB phosphorylation unnecessary for cell cycle progression, we have found that the 12S wild-type E1A product is capable o... |
2072900 | In vivo assembly of yeast mitochondrial alpha-ketoglutarate dehydrogenase complex. | The assembly of alpha-ketoglutarate dehydrogenase complex (KGDC) has been studied in wild-type Saccharomyces cerevisiae and in respiratory-deficient strains (pet) with mutations in KGD1 and KGD2, the structural genes for alpha-ketoglutarate dehydrogenase (KE1) and dihydrolipoyl transsuccinylase (KE2) components, respec... |
1649315 | A temperature-sensitive lesion in the small subunit of the vaccinia virus-encoded mRNA capping enzyme causes a defect in viral telomere resolution. | Using pulsed-field gel electrophoresis, we demonstrated that the temperature-sensitive (ts) conditional lethal mutant ts9383 is, at the nonpermissive temperature, defective in the resolution of concatemeric replicative intermediate DNA to linear 185-kb monomeric DNA genomes. The resolution defect was shown to be the re... |
1830110 | Molecular characterization of human immunodeficiency virus type 1 cloned directly from uncultured human brain tissue: identification of replication-competent and -defective viral genomes. | All presently available replication-competent proviral clones of human immunodeficiency virus type 1 (HIV-1) are derived from cell culture-amplified virus. Since tissue culture is highly selective for viral strains with an in vitro growth advantage, such clones may not be representative of the biologically relevant vir... |
2065666 | Affinity purification of transcription factor IIA from HeLa cell nuclear extracts. | One of the general transcription factors, TFIIA, was purified to homogeneity from HeLa cell nuclear extracts by yeast TFIID affinity chromatography. Human TFIIA had a molecular weight of approximately 38 kd. It was able to associate with the complex formed by yeast TFIID and the TATA elements of the adenovirus E4 and M... |
1712291 | Molecular requirements for the mu-induced light chain gene rearrangement in pre-B cells. | During B cell differentiation rearrangement of immunoglobulin (Ig) genes is partially regulated by the Ig proteins. Rearrangement of heavy (H) chain genes is inhibited, whilst that of light (L) chain genes is induced by the membrane form of the mu H chain. In order to analyse additional structural requirements of mu in... |
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