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2824815 | In vivo and in vitro models of demyelinating disease: activation of the adenylate cyclase system influences JHM virus expression in explanted rat oligodendrocytes. | The specificity of JHM virus (JHMV) tropism for rat oligodendrocytes, as one of the primary host cells in the central nervous system, is maintained after explanation (S. Beushausen and S. Dales, Virology 141:89-101, 1985). The temporal correlation between onset of resistance to JHMV infection in vivo, completion of mye... |
3500185 | Regulation of factor XIa activity by platelets and alpha 1-protease inhibitor. | We have studied the complex interrelationships between platelets, Factor XIa, alpha 1-protease inhibitor and Factor IX activation. Platelets were shown to secrete an inhibitor of Factor XIa, and to protect Factor XIa from inactivation in the presence of alpha 1-protease inhibitor and the secreted platelet inhibitor. Th... |
2960665 | Mutational analysis of the lambda int gene: DNA sequence of dominant mutations. | We have combined techniques of genetic and physical mapping with rapid DNA sequence analysis to identify the nucleotide change in lambda int mutations. These mutations define two dominant phenotypic classes: (i) recombination that is partially independent of accessory factors, and (ii) inhibition of wild-type Int by mi... |
2824451 | Transposition of Tn1000: activity of single or directly repeated termini. | Tn1000 (gamma delta) termini IRR and IRL, or direct repetitions of IRR-IRL carried by pBR322 derivatives mediate cointegration with pOX38 at similar rates. Structures of product plasmids indicate that the transposed segments correspond to DNA bounded by IR segments in the donor plasmid. Such structures could arise by s... |
3316191 | Genes encoding two lipoproteins in the leuS-dacA region of the Escherichia coli chromosome. | The coding of two rare lipoproteins by two genes, rlpA and rlpB, located in the leuS-dacA region (15 min) on the Escherichia coli chromosome was demonstrated by expression of subcloned genes in a maxicell system. The formation of these two proteins was inhibited by globomycin, which is an inhibitor of the signal peptid... |
2820828 | Amelioration of hepatic encephalopathy by pharmacologic antagonism of the GABAA-benzodiazepine receptor complex in a rabbit model of fulminant hepatic failure. | Three separate, but allosterically interacting, sites on the gamma-aminobutyric acid (GABA) supramolecular complex in the brain were pharmacologically blocked in rabbits with hepatic encephalopathy due to galactosamine-induced fulminant hepatic failure to determine whether decreased GABAergic neurotransmission can amel... |
2484752 | Microbial amylases. | Amylases are of tremendous importance in the food industry. Different enzymes used separately or together convert starch into glucose, maltose, dextrins or cyclodextrins. Most enzymes of industrial importance are of microbial origin, and the list of amylases produced by molecular cloning is rapidly expanding. |
19431707 | A kinetic model for the energy transfer in phycobilisomes. | A kinetic model for the energy transfer in phycobilisome (PBS) rods of Synechococcus 6301 is presented, based on a set of experimental parameters from picosecond studies. It is shown that the enormous complexity of the kinetic system formed by 400-500 chromophores can be greatly simplified by using symmetry arguments. ... |
18964438 | Liquid-liquid extraction of metal ions by the 6-membered N-containing macrocycle hexacyclen. | The nitrogen-containing analogue of 18-crown-6, 1,4,7,10,13,16-hexa-azaoctadecane (hexacyclen)] was studied as a reagent for complexation and extraction of some metal ions. It was found that with this reagent and methyl isobutyl ketone, metal ions such as silver(I), mercury(II), copper(II), platinum(II) and palladium(I... |
3327449 | Immunofluorescent studies of the anti-microtubule effects of the anti-cancer drug estramustine. | Immunofluorescent studies in human prostatic carcinoma cells (DU 145) and cultured squirrel fish epithelial cells (a non-cancer cell) revealed that estramustine, a conjugate of estradiol and nor-nitrogen mustard, possessed microtubule disassembly properties. Sixty microM estramustine produced disassembly at both the pr... |
3325507 | Molecular assembly of the lipoprotein trimer on the peptidoglycan layer of Escherichia coli. | The molecular assembly of the major outer membrane lipoprotein on the peptidoglycan layer was studied using two hybrid genes coding for different OmpF-lipoprotein hybrid proteins. One gene codes for a "lipoprotein" in which the diacylglyceryl cysteine residue is replaced with the Ala-Glu residue of the NH2 terminus of ... |
3436965 | Interactions of pig brain cytosolic sialidase with gangliosides. The formation of catalytically inactive enzyme-ganglioside complexes requires homogeneous ganglioside micelles and is a reversible phenomenon. | Cytosolic sialidase A, obtained from pig brain and purified, interacts with ganglioside GT1b giving two catalytically inactive enzyme-ganglioside complexes. Treatment of these complexes with Triton X-100 under given conditions (1% detergent; 1 h at 37 degrees C; 0.1 M acetic acid-sodium acetate buffer, pH 4.8) leads to... |
3481262 | Supramolecular structure of tripeptidyl peptidase II from human erythrocytes as studied by electron microscopy, and its correlation to enzyme activity. | Tripeptidyl peptidase II is an extralysosomal serine peptidase of an unusually large size, i.e. Mr greater than 10(6) for the native enzyme and Mr 135000 for the subunit. The enzyme from human erythrocytes was studied by electron microscopy on samples negatively stained by ammonium molybdate. Two different structural r... |
2449122 | Monoclonal antibodies to TEM-1 plasmid-mediated beta-lactamase. | At least 28 plasmid-mediated beta-lactamases have been described in gram-negative bacteria. To assess the relationship among these enzymes, we produced and characterized 28 murine monoclonal antibodies to the TEM-1 plasmid-mediated beta-lactamase. Radial immunodiffusion identified 3 monoclonal antibodies as immunoglobu... |
2963210 | Reconstitution of the U1 small nuclear ribonucleoprotein particle. | Although the U1 small nuclear ribonucleoprotein particle (snRNP) was the first mRNA-splicing cofactor to be identified, the manner in which it functions in splicing is not precisely understood. Among the information required to understand how U1 snRNP participates in splicing, it will be necessary to know its structure... |
3323882 | Genetic and biochemical characterization of clathrin-deficient Saccharomyces cerevisiae. | Clathrin is important but not essential for yeast cell growth and protein secretion. Diploid Saccharomyces cerevisiae cells heterozygous for a clathrin heavy-chain gene (CHC1) disruption give rise to viable, slow-growing, clathrin heavy-chain-deficient meiotic progeny (G. Payne and R. Schekman, Science 230:1009-1014, 1... |
3427582 | Formation of 6-O-alpha-maltosylcyclomalto-oligosaccharides by transfer action of three debranching enzymes. | O-Maltosylcyclomaltohexaoses (G2-cG6) were formed in yields of 24.3 and 23.2 mmol from 40 mmol of alpha-maltosyl fluoride (alpha-G2F) and 90 mmol of cyclomaltohexaose (cG6) by the transfer action of pullulanase from Aerobacter aerogenes (A-pullulanase) and isoamylase from Pseudomonas amyloderamosa, respectively. These ... |
3427579 | Reaction of cyclodextrins with propylene oxide or with glycidol: analysis of product distribution. | Reaction of cyclomalto-hexaose, -heptaose, or -octaose with propylene oxide in strong aqueous alkali gave products in which distribution of the degrees of substitution was relatively narrow and nearly symmetrical, and increased with the average degree of substitution. When an equimolar mixture of cyclomalto-hexaose, he... |
3427190 | Contrasting molecular dynamics in red and purple membrane fractions of the Halobacterium halobium. | 2H-nuclear magnetic resonance (NMR) has been used to study the dynamics of amino acid residues in bacteriorhodopsin with results that depend on the method of sample preparation. We show here that in [2H]-leucine-labeled samples the intensity of the isotropic signal varies according to the degree of residual contaminati... |
2827799 | The location of cytochrome c on the surface of ultrathin lipid multilayer films using x-ray diffraction. | X-ray diffraction and spectroscopic techniques were used to characterize ultrathin fatty acid multilayers having a bound surface layer of cytochrome c. Three to six monolayers of arachidic acid were deposited onto an alkylated glass surface, using the Langmuir-Blodgett method. These fatty acid multilayer films were sto... |
3427183 | Incorporation kinetics in a membrane, studied with the pore-forming peptide alamethicin. | The reaction of fluorescence-labeled alamethicin with unilamellar phospholipid vesicles (DOPC and DMPC) has been investigated in a stopped-flow apparatus. Clearly single exponential time functions have been observed at temperatures above the phase transition of the bilayer. This can be interpreted in terms of an essent... |
2962570 | Myosin from pancreatic acinar carcinoma cells. Isolation, characterization and demonstration of heavy- and light-chain phosphorylation. | Myosin has been identified in a variety of non-muscle cells, and is believed to play a role in maintenance of cell shape, locomotion, cytokinesis, exocytosis and other cellular functions. In this paper we describe the purification of myosin from a pancreatic acinar-cell carcinoma of the rat which forms solid tumours, b... |
3121799 | The neuromuscular pathology of experimental Chagas' disease. | In this work, we describe skeletal muscle, neuromuscular junction, nerve and spinal cord lesions in the mouse model system of Chagas' disease. Myositis was a common finding and Trypanosoma cruzi amastigote nests were frequently found in the muscle fibers. Angular atrophy, targetoid fibers, groups of atrophic fibers, fi... |
3693543 | High-performance liquid chromatography analysis of mycolic acids as an aid in laboratory identification of Rhodococcus and Nocardia species. | High-performance liquid chromatography analysis of the p-bromophenacyl esters of mycolic acids from whole organisms gave chromatographic patterns that were useful in differentiation of Rhodococcus and Nocardia species. Rhodococcus equi, R. erythropolis, and R. rhodochrous contained more-polar mycolic acids and were eas... |
2826514 | Determination of association constants of beta-cyclodextrin and beta-cyclodextrin-bearing polymers with drugs by high-performance liquid chromatography. | A high-performance liquid chromatographic (HPLC) support was prepared, based on silica beads coated with a beta-cyclodextrin-containing polymer, which allows the elution of solutes in order of their affinity for beta-cyclodextrin. Binding constants were determined from the retention data for drugs eluted with pure buff... |
3693495 | Benzyl esters of C2-C20 fatty acids and metabolically relevant carboxylic acids. Preparation and gas chromatography-mass spectrometry. | Short-, medium- and long-chain fatty acids, and other types of metabolically relevant carboxylic acids like hydroxy-, keto-, aromatic and dicarboxylic acids, were analyzed by capillary gas chromatography. For separation, benzyl ester derivatives were used, prepared by reaction of the potassium carboxylates with benzyl ... |
2891501 | The role of the multichain IL-2 receptor complex in the control of normal and malignant T-cell proliferation. | Antigen-induced activation of resting T-cells induces the synthesis of interleukin-2 (IL-2), as well as the expression of specific cell surface receptors for this lymphokine. There are at least two forms of the cellular receptors for IL-2, one with a very high affinity and the other with a lower affinity. We have ident... |
2825175 | Genetic analysis of the interaction of the insertion sequence IS903 transposase with its terminal inverted repeats. | The insertion sequence IS903 has perfect, 18-base-pair terminal repeats that are the presumed binding sites of its transposase. We have isolated mutations throughout this inverted repeat and analyzed their effect on transposition. We show that every position in the inverted repeat (with the possible exception of positi... |
2825167 | Efficient Tn10 transposition into a DNA insertion hot spot in vivo requires the 5-methyl groups of symmetrically disposed thymines within the hot-spot consensus sequence. | Transposon Tn10 inserts preferentially at particular insertion "hot spots" that share a symmetrical 6-base-pair consensus sequence: 5' GCTNAGC 3'. The protein that recognizes this sequence is not known but is likely to be the Tn10-encoded transposase protein. We present evidence that the 5-methyl groups of the two thym... |
3684568 | Sequence-targeted chemical modifications of nucleic acids by complementary oligonucleotides covalently linked to porphyrins. | Oligo-heptathymidylates covalently linked to porphyrins bind to complementary sequences and can induce local damages on the target molecule. In dark reactions, iron porphyrin derivatives exhibited various chemical reactivities resulting in base oxidation, crosslinking and chain scission reactions. Reactions induced by ... |
2824984 | A molecular model for activation of a 5-hydroxytryptamine receptor. | The extension of a model proposed previously for molecular recognition at a serotonin (5-hydroxytryptamine (5-HT) ) receptor makes possible the formulation of a molecular mechanism of receptor activation. The activation mechanism proposed here is based on the changes induced in the drug and in a model receptor by the i... |
3119790 | Two-stage expression of neurofilament polypeptides during rat neurogenesis with early establishment of adult phosphorylation patterns. | Monoclonal antibodies (mAbs) to rat neurofilament (NF) proteins NF-L, NF-M, and NF-H were used to examine the developmental programs of NF expression in rat embryos. The ability of these mAbs to recognize differentially phosphorylated states of NF-M and NF-H (Lee et al., 1987, the preceding paper) was exploited in orde... |
3680387 | Nucleated assembly of Chlamydomonas and Volvox cell walls. | The Chlamydomonas reinhardtii cell wall is made up of hydroxyproline-rich glycoproteins, arranged in five distinct layers. The W6 (crystalline) layer contains three major glycoproteins (GP1, GP2, GP3), selectively extractable with chaotropic agents, that self-assemble into crystals in vitro. A system to study W6 assemb... |
3316247 | Changes in heterogeneous nuclear RNP core polypeptide complements during the cell cycle. | Mammalian heterogeneous nuclear RNP (hnRNP) subcomplexes are shown to be comprised of 14-17 basic A and B core group polypeptides (chrp) when subjected to two-dimensional immunoblot analysis. These proteins are normally confined to the nucleus but are distributed throughout the cell during mitosis. However, not all of ... |
3316206 | Assembly of collagen fibrils de novo by cleavage of the type I pC-collagen with procollagen C-proteinase. Assay of critical concentration demonstrates that collagen self-assembly is a classical example of an entropy-driven process. | Type I procollagen was purified from the medium of cultured human fibroblasts incubated with 14C-labeled amino acids, the NH2-terminal propeptides were cleaved with procollagen N-proteinase, and the resulting pC-collagen was isolated by gel filtration chromatography. pC-collagen did not assemble into fibrils or large a... |
2960668 | A conformational change of N-iodoacetyl-N'-(5-sulfo-1-naphthyl)ethylenediamine-labeled sarcoplasmic reticulum Ca2+-ATPase upon ATP binding to the catalytic site. | Sarcoplasmic reticulum vesicles were modified with a fluorescent thiol reagent, N-iodoacetyl-N'-(5-sulfo-1-naphthyl)ethylenediamine. One mol of readily reactive thiols per mol of the Ca2+-ATPase was labeled without a loss of the catalytic activity. The fluorescence of the label increased by 8% upon binding of Ca2+ to t... |
2445592 | A 60-kDa polypeptide in mammalian cells with epitopes related to actin. | We have identified a novel actin-related 60-kDa polypeptide in mammalian cells. The relatedness of this polypeptide to actin is indicated by its affinity for DNase I, two monoclonal anti-actin antibodies, and two independent peptide-specific anti-actin antibodies which bind to actin at around amino acid 244. It is not ... |
3674205 | Anti-Fx1A induces association of Heymann nephritis antigens with microfilaments of cultured glomerular visceral epithelial cells. | Binding of anti-Fx1A to Heymann nephritis antigens (HA) on rat glomerular epithelial cells (GECs) in culture leads to capping and disappearance of antigens from the cell surface. This process may contribute to the formation of glomerular subepithelial immune deposits in vivo. The authors differentially extracted GECs t... |
3118376 | Comparison of the effects of microtubule-associated protein 2 and tau on the packing density of in vitro assembled microtubules. | I have compared the effects of microtubule-associated protein 2 (MAP-2) and tau on the packing density of sedimented microtubules. Microtubules assembled in vitro in taxol were pelleted by centrifugation. The volumes of the resulting pellets were calculated from their weights assuming a specific gravity of 1 and then w... |
2959961 | Type II insulin-like growth factor receptor is present in rat serum. | We previously identified in fetal rat serum a component capable of specifically binding radiolabeled insulin-like growth factor type II (IGF-II) that is considerably larger than both the fetal (40 kDa) and the adult (150 kDa) carrier proteins. We now present immunologic and affinity crosslinking data to show that this ... |
3478708 | Spin glasses and the statistical mechanics of protein folding. | The theory of spin glasses was used to study a simple model of protein folding. The phase diagram of the model was calculated, and the results of dynamics calculations are briefly reported. The relation of these results to folding experiments, the relation of these hypotheses to previous protein folding theories, and t... |
3118369 | Myristoylated alpha subunits of guanine nucleotide-binding regulatory proteins. | Antisera directed against specific subunits of guanine nucleotide-binding regulatory proteins (G proteins) were used to immunoprecipitate these polypeptides from metabolically labeled cells. This technique detects, in extracts of a human astrocytoma cell line, the alpha subunits of Gs (stimulatory) (alpha 45 and alpha ... |
2822929 | A 500-MHz proton nuclear magnetic resonance study of mu opioid peptides in a simulated receptor environment. | The structure-activity relationship of several mu selective opioid peptides has been evaluated on the basis of both experimental and theoretical approaches. The conformations of Tyr-D-Ala-Phe-Gly-NH2, the tetrapeptide N-fragment of dermorphin, and two analogues have been studied in solution by 1H NMR spectroscopy. The ... |
2822666 | Replication properties of pIM13, a naturally occurring plasmid found in Bacillus subtilis, and of its close relative pE5, a plasmid native to Staphylococcus aureus. | A naturally occurring plasmid from Bacillus subtilis, pIM13, codes for constitutively expressed macrolide-lincosamide-streptogramin B (MLS) resistance, is stably maintained at a high copy number, and exists as a series of covalent multimers. The complete sequence of pIM13 has been reported (M. Monod, C. Denoya, and D. ... |
3667523 | Three-dimensional structure of the regular tetragonal surface layer of Azotobacter vinelandii. | Fragments of the Azotobacter vinelandii tetragonal surface (S) layer, free of outer membrane material, were obtained by treating whole cells with 100 microM EDTA. The three-dimensional structure of the S layer was reconstructed from tilted-view electron micrographs of the S-layer fragments, after computer-assisted imag... |
3666956 | The immunogenicity and antigenicity of lipid A are influenced by its physicochemical state and environment. | We investigated the immunogenicity and antigenicity of synthetic lipid A and partial structures thereof. Included in the study were compounds which varied in the position of phosphate (1-mono-, 4'-mono-, and 1,4'-bisphosphates) and in the acylation (type, number, and distribution of fatty acids) and, in the case of mon... |
2822257 | The localization of replication origins on ARS plasmids in S. cerevisiae. | Replication intermediates from the yeast 2 microns plasmid and a recombinant plasmid containing the yeast autonomous replication sequence ARS1 have been analyzed by two-dimensional agarose gel electrophoresis. Plasmid replication proceeds through theta-shaped (Cairns) intermediates, terminating in multiply interlocked ... |
3310236 | Computer-aided molecular design. | Theoretical chemistry, as implemented on fast computers, is beginning to yield accurate predictions of the thermodynamic and kinetic properties of large molecular assemblies. In addition to providing detailed insights into the origins of molecular activity, theoretical calculations can be used to design new molecules w... |
3477803 | The heavy chain of Acanthamoeba myosin IB is a fusion of myosin-like and non-myosin-like sequences. | Acanthamoeba castellanii myosins IA and IB demonstrate the catalytic properties of a myosin and can support analogues of contractile and motile activity in vitro, but their single, low molecular weight heavy chains, roughly globular shapes, and inabilities to self-assemble into filaments make them structurally atypical... |
3655980 | Severe hypervitaminosis A in siblings: evidence of variable tolerance to retinol intake. | A 2-year-old boy had signs and symptoms of chronic hypervitaminosis A. A course of increasing severity led to eventual death. A younger brother later had similar clinical features. Chicken liver spread containing up to 420 IU/g vitamin A was the likely source of intoxication. Markedly elevated circulating retinyl ester... |
2958580 | Thymocytes with the predicted properties of pre-T cells. | T cell receptor synthesis in thymocytes was examined by the differential immunoprecipitation of receptors from the surfaces and interiors of metabolically labeled newborn and adult thymocytes. Precipitated molecules were then analyzed for size, charge, and state of glycosylation. Our experiments identified cells within... |
3115901 | Use of monoclonal antibodies to protein F of Pseudomonas aeruginosa as opsonins for phagocytosis by macrophages. | Five protein F-specific monoclonal antibodies were found to opsonize Pseudomonas aeruginosa for complement-independent phagocytosis by unelicited mouse peritoneal macrophages, mouse macrophage cell line P388D1, and human monocyte-derived macrophages. Immunoglobulin G1 antibodies seemed to be a preferred isotype. |
3653983 | Bacteroides gingivalis-Actinomyces viscosus cohesive interactions as measured by a quantitative binding assay. | There is limited evidence, mostly indirect, to suggest that the adherence of Bacteroides gingivalis to teeth may be enhanced by the presence of gram-positive dental plaque bacteria like Actinomyces viscosus. The purpose of this study was to carry out direct quantitative assessments of the cohesion of B gingivalis and A... |
3041040 | Missense mutations in the VP1 gene of simian virus 40 that compensate for defects caused by deletions in the viral agnogene. | Simian virus 40 mutants lacking sequences in the late leader region are viable but produce smaller plaques than does wild-type virus. Within three passages at low multiplicities of infection, virus stocks of several such mutants accumulated variants that synthesized an altered form of the major virion protein, VP1, hav... |
24225865 | Correlation of photosystem-II complexes with exoplasmatic freeze-fracture particles of thylakoids of the cyanobacterium Synechococcus sp. | The supramolecular structure of the exoplasmic freeze-fracture particles of thylakoids of the thermophilic cyanobacterium Synechococcus sp. is compared with that of isolated photosystem-II complexes. The in-situ EF particles are scattered on the thylakoids or organized in rows of variable length; the latter aligned par... |
2833483 | Secondary palate development in the domestic duck (Khaki Campbell). An electron microscopic, histochemical, autoradiographic and biochemical study. | Prenatal development of the secondary palate in duck was studied using light and electron microscopic, histochemical, autoradiographic and biochemical techniques. The secondary palate of duck develops between Days 7-12 of incubation (HH 25-37). During this period the palatal shelves grow horizontally toward one another... |
3441012 | Description of the topological entanglement of DNA catenanes and knots by a powerful method involving strand passage and recombination. | We utilize a recently discovered, powerful method to classify the topological state of knots and catenanes. In this method, each such form is associated with a unique polynomial. These polynomials allow a rigorous determination of whether knotted or catenated DNA molecules that appear distinct actually are, and indicat... |
3430342 | gamma-Cyclodextrin:testosterone complex suitable for sublingual administration. | A crystalline complex of testosterone with gamma-cyclodextrin was evaluated for solubility and dissolution rate. Whereas these parameters were at least an order of magnitude lower than those of testosterone complexes with amorphous derivatives of cyclodextrins, the properties of the crystalline complex enabled the prep... |
3693168 | Cardiopulmonary function during 7 h of constant-dose halothane and methoxyflurane. | Cardiopulmonary effects of prolonged, constant-alveolar-dose halothane (HAL) and methoxyflurane (MOF) in O2 anesthesia on spontaneously breathing dogs were determined. One hour after anesthetic induction, end-tidal concentration was set at 1.04% HAL or 0.28% MOF [each representing 1.2 minimum alveolar concentration (MA... |
3319626 | Tumor promoter and fibronectin induce actin stress fibers and focal adhesion sites in spreading human erythroleukemia (HEL) cells. | The effects of plasma fibronectin (pFn) and the tumor promoter 12-0-tetradecanoyl-phorbol-13-acetate (TPA) on adhesion and cytoskeletal organization of human erythroleukemia (HEL) cells were studied. HEL cells, that normally grow in suspension, attached rapidly on pFn-coated growth substratum and some cells showed spre... |
3691475 | Structure and dynamics of the phosphatidylcholine and the phosphatidylethanolamine head group in L-M fibroblasts as studied by deuterium nuclear magnetic resonance. | Mouse fibroblast L-M cells were grown in tissue culture medium containing selectively deuterated choline or ethanolamine. Both compounds were incorporated into the corresponding phospholipids at levels greater than 50% thus leading to a selective deuteration of these phospholipid head groups. Choline and ethanolamine w... |
3689347 | High-performance liquid chromatography of type-III heptocarboxylic porphyrinogen isomers. | A reversed-phase h.p.l.c. system is described for the separation of the four type-III heptacarboxylic porphyrinogen isomers. The effects of buffer concentration, pH and type and proportion of organic modifier in the mobile phase on retention and resolution of isomers were studied. Optimum separation on an ODS-Hypersil ... |
3316988 | Insertions of up to 17 amino acids into a region of alpha-tubulin do not disrupt function in vivo. | Microtubules in yeasts are essential components of the mitotic and meiotic spindle and are necessary for nuclear movement during cell division and mating. The yeast Saccharomyces cerevisiae has two alpha-tubulin genes, TUB1 and TUB3, either of which alone is sufficient for these processes when present in a high enough ... |
2824994 | DNA sequence requirements for replication of polyomavirus DNA in vivo and in vitro. | Cell extracts of FM3A mouse cells replicate polyomavirus (Py) DNA in the presence of immunoaffinity-purified Py large T antigen, deoxynucleoside triphosphates, ATP, and an ATP-generating system. This system was used to examine the effects of mutations within or adjacent to the Py core origin (ori) region in vitro. The ... |
3119991 | Regulation of histone and beta A-globin gene expression during differentiation of chicken erythroid cells. | The expression of the genes for several histones and beta A-globin was examined in the chicken erythroid cells lineage. During the transition from CFU-(E) to the mature erythrocyte, histone H5 gradually increased fourfold in nuclei with little concomitant displacement of the H1 histones. This resulted in a 70% net incr... |
3683394 | Metal-dependent binding of a factor in vivo to the metal-responsive elements of the metallothionein 1 gene promoter. | Using the technique of genomic footprinting, we demonstrate cadmium-inducible protection from dimethyl sulfate (DMS) modification of guanine residues in vivo in five metal-responsive elements (MREs) in the promoter of the rat metallothionein 1 (MT-1) gene. We also identify a site of extreme DMS hyperreactivity which, l... |
3478681 | Binary liquid phase separation and critical phenomena in a protein/water solution. | We have investigated the phase diagram of aqueous solutions of the bovine lens protein gamma II-crystallin. For temperatures T less than Tc = 278.5 K, we find that these solutions exhibit a reversible coexistence between two isotropic liquid phases differing in protein concentration. The dilute and concentrated branche... |
3478677 | Conformational studies of alpha-globin in 1-propanol: propensity of the alcohol to limit the sites of proteolytic cleavage. | Selective condensation of the unprotected fragments of alpha-globin--namely, alpha 1-30 and alpha 31-141--is catalyzed by Staphylococcus aureus V8 protease in the presence of 25% 1-propanol. The propensity of 1-propanol to induce the alpha-helical conformation and to generate a "native-like" topology for the polypeptid... |
2444601 | Electron microscopic observations of reconstituted proteoliposomes with the purified major intrinsic membrane protein of eye lens fibers. | The purified major intrinsic protein of the lens fiber plasma membrane (MP26) reconstituted into liposomes favored membrane-to-membrane close contacts as visualized by freeze fracture and immunoelectron microscopy. Reconstituted apposed unilamellar vesicles formed pentalaminar profiles, and multilamellar liposomes show... |
3662526 | The effect of bovine serum albumin on the synthesis of prostaglandin and incorporation of [3H]acetate into platelet-activating factor. | The binding of fatty acids by bovine serum albumin (BSA) is well documented. However, the interaction between the synthesis of prostaglandins (PGs) and the trapping of arachidonate released from cellular lipid stores is not as well understood. In this communication, we relate the trapping of fatty acids to the synthesi... |
2821510 | The production of hybrid Ty:IFN virus-like particles in yeast. | The yeast retrotransposon Ty encodes proteins that assemble into virus-like particles (Ty-VLPs) which can be readily purified. We have recently shown that expression of the pl protein encoded by the TYA gene of Ty is sufficient for particle formation. In this paper we show that when a heterologous coding sequence, huma... |
3309090 | An ultrastructural study of dermal nerves in early human leprosy. | Skin biopsies from the cutaneous lesions of seven patients with indeterminate, BT, BL, and LL leprosy of less than 1 year's duration were examined by light and electron microscopy. Inflammatory cells, which marked the location of Mycobacterium leprae in bacilliferous cases (BL and LL) were most frequently and consisten... |
2888772 | Lysyl oxidase activity and elastin/glycosaminoglycan interactions in growing chick and rat aortas. | Hydrophobic tropoelastin molecules aggregate in vitro in physiological conditions and form fibers very similar to natural ones (Bressan, G. M., I. Pasquali Ronchetti, C. Fornieri, F. Mattioli, I. Castellani, and D. Volpin, 1986, J. Ultrastruct. Molec. Struct. Res., 94:209-216). Similar hydrophobic interactions might be... |
2821013 | Gelsolin is expressed in early erythroid progenitor cells and negatively regulated during erythropoiesis. | We have identified an approximately 85-kD protein in chicken erythrocytes which is immunologically, structurally, and functionally related to the gelsolin found in many muscle and nonmuscle cell types. Cell fractionation reveals a Ca2+-dependent partitioning of gelsolin into the soluble cytoplasm and the membrane-assoc... |
2958483 | Structural changes accompanying phosphorylation of tarantula muscle myosin filaments. | Electron microscopy has been used to study the structural changes that occur in the myosin filaments of tarantula striated muscle when they are phosphorylated. Myosin filaments in muscle homogenates maintained in relaxing conditions (ATP, EGTA) are found to have nonphosphorylated regulatory light chains as shown by ure... |
3308906 | Translocation and clustering of endosomes and lysosomes depends on microtubules. | Indirect immunofluorescence labeling of normal rat kidney (NRK) cells with antibodies recognizing a lysosomal glycoprotein (LGP 120; Lewis, V., S.A. Green, M. Marsh, P. Vihko, A. Helenius, and I. Mellman, 1985, J. Cell Biol., 100:1839-1847) reveals that lysosomes accumulate in the region around the microtubule-organizi... |
3651450 | Lipid specific penetration of melittin into phospholipid model membranes. | The relative depth of penetration of melittin into egg phosphatidylcholine and bovine heart cardiolipin model membranes was investigated using fluorescence spectroscopy techniques. The tryptophan intrinsic fluorescence shift suggests a more hydrophobic surrounding of this residue in cardiolipin, while the accessibility... |
2957695 | Cranin: a laminin-binding protein of cell membranes. | We report that a 120-kDa glycoprotein is the predominant laminin-binding protein detected within plasma membranes of rodent NG108-15 neural hybrid cells, embryonic chicken brain, and mouse 3T3 fibroblasts. This protein was detected when membrane extracts were separated by PAGE, transferred to nitrocellulose, and incuba... |
3624491 | Effect of intranasal histamine on nasal mucosal blood flow and the antidiuretic activity of desmopressin. | The effects of exogenous histamine on nasal mucosal blood flow and the systemic activity of intranasally administered desmopressin, a vasopressin analogue, were studied in normal volunteers. Ten subjects received either saline or histamine (1, 20, 100, and 500 micrograms) by intranasal spray. Maximal nasal mucosal bloo... |
2957361 | Nucleotide sequence of the beta-cyclodextrin glucanotransferase gene of alkalophilic Bacillus sp. strain 1011 and similarity of its amino acid sequence to those of alpha-amylases. | The nucleotide sequence of the gene for cyclodextrin glucanotransferase of alkalophilic Bacillus sp. strain 1011 was determined. The deduced amino acid sequence at the NH2-terminal side of the enzyme showed a high homology with the sequences of alpha-amylase in the three regions which constitutes the active centers of ... |
3624205 | Involvement of both cellulose fibrils and a Ca2+-dependent adhesin in the attachment of Rhizobium leguminosarum to pea root hair tips. | We have previously described an assay for the attachment of Rhizobium bacteria to pea root hair tips (cap formation) which was used as a model to study the attachment step in the nodulation process. Under all conditions tested, a positive correlation was observed between the percentage of fibrillated cells and the abil... |
2442137 | Molecular sieving through S layers of Bacillus stearothermophilus strains. | The permeability properties and the exclusion limits of the crystalline surface layers (S layers) of two selected strains of Bacillus stearothermophilus were investigated. Measurements were performed of passive solute uptake into the intracellular space of native or glutaraldehyde-treated sacculi. Native sacculi were p... |
3039516 | Morphological changes of an inflammatory myopathy in rhesus monkeys with simian acquired immunodeficiency syndrome. | Eleven of 25 rhesus monkeys which died of simian acquired immunodeficiency syndrome (SAIDS) caused by infection with a type D retrovirus related to Mason-Pfizer monkey virus showed evidence of muscle weakness and atrophy and had elevated levels of muscle enzymes. Biopsies of affected muscle studied with enzyme histoche... |
3039169 | The membrane glycoprotein of Friend spleen focus-forming virus: evidence that the cell surface component is required for pathogenesis and that it binds to a receptor. | The leukemogenic membrane glycoprotein of Friend spleen focus-forming virus (SFFV) has an apparent Mr of 55,000 (gp55), is encoded by a recombinant env gene, and occurs on cell surfaces and in intracellular organelles. There is evidence that the amino-terminal region of gp55 forms a dualtropic-specific domain that is c... |
2441076 | Rabies virus infection of cultured rat sensory neurons. | The axonal transport of rabies virus (challenge virus strain of fixed virus) was studied in differentiated rat embryonic dorsal root ganglion cells. In addition, we observed the attachment of rabies virus to neuronal extensions and virus production by infected neurons. A compartmentalized cell culture system was used, ... |
3039164 | Monoclonal antibody-aided characterization of cellular p220 in uninfected and poliovirus-infected HeLa cells: subcellular distribution and identification of conformers. | A monoclonal antibody directed against the Mr-220,000 subunit (p220) of the mRNA cap-binding complex has been prepared and used to analyze the sucrose gradient sedimentation and subcellular location of p220 and its poliovirus-induced cleavage products. The antibody reacted with p220 on immunoblots of cell lysates from ... |
2896225 | Release of pertussis toxin and its interaction with outer-membrane antigens. | The absence of subunit S3 in cell-associated pertussis toxin (PT) from a mutant of Bordetella pertussis which failed to produce cell-free toxin suggested that this subunit was involved in the release of PT into the culture medium. The addition of methylated beta-cyclodextrin (MCD) to the culture medium caused a small b... |
16578814 | Exciton interactions in reaction centers of the photosynthetic bacterium Rhodopseudomonas viridis probed by optical triplet-minus-singlet polarization spectroscopy at 1.2 K monitored through absorbance-detected magnetic resonance. | Linear dichroic triplet-minus-singlet [LD-(T - S)] spectra of isolated reaction centers of the photosynthetic bacterium Rhodopseudomonas viridis have been measured at 1.2 K with the linear dichroic absorbance-detected magnetic resonance (LD-ADMR) technique for two mutually perpendicular directions of the preferred axis... |
3326683 | Regulatory properties of brain glutamate decarboxylase. | 1. Glutamate decarboxylase is a focal point for controlling gamma-aminobutyric acid (GABA) synthesis in brain. Several factors that appear to be important in the regulation of GABA synthesis have been identified by relating studies of purified glutamate decarboxylase to conditions in vivo. 2. The interaction of glutama... |
3122479 | The substrate specificity of the enzyme amyloglucosidase (AMG). Part I. Deoxy derivatives. | The eight possible monodeoxy derivatives of methyl beta-maltoside and two bisdeoxy derivatives have been synthesized. The unprotected glycosides have all been investigated by NMR (1H and 13C) spectroscopy in order to confirm their structures and to obtain supporting information about their preferred solution conformati... |
3321723 | Cytotoxic cellular mediators of the immune response to neoplasia: a review. | Immunotherapy in the management of neoplastic disease has recently been a major focus of scientific attention. Studies in vitro and in animal systems have provided the basis for the first trials of cellular immunotherapy for neoplasia in humans. Work over the past ten years has identified several distinct populations o... |
3693463 | Chromatographic separation of racemic amino acids by use of chiral crown ether-coated reversed-phase packings. | Chromatographic packings for optical resolution of underivatized racemic amino acids were prepared by dynamic coating of a chiral crown ether on reversed-phase packings, and their characteristics were examined. Almost all the amino acids commonly found in proteins were finely separated into their enantiomers when a dil... |
3318939 | [Malignant transformation and changes in various physico-chemical properties of macromolecules and supramolecular structures. I. Nucleic acids]. | The relations between heat and hydrate properties of nucleic acids, proteins and supramolecular structures and concentration of various metal ions in them are shown. Global disturbance of metabolism of metal ions accompanying malignization is described. This disturbance causes some changes in the activity of the centra... |
3683373 | [Supramolecular organization of enzymes of the tricarboxylic acid cycle]. | In virtue of analysis of data on the interaction of tricarboxylic acid cycle enzymes with the mitochondrial inner membrane and data on the enzyme-enzyme interactions, the spatial structure for the tricarboxylic acid cycle enzyme complex (tricarboxylic acid cycle metabolon) is proposed. The alpha-ketoglutarate dehydroge... |
3678322 | Clinical pharmacology of sodium butyrate in patients with acute leukemia. | Since cancer may be regarded as a disease of differentiation and sodium butyrate induces differentiation of malignant cells in vitro, a study of the clinical pharmacology of sodium butyrate was undertaken. Nine patients with acute myeloid (n = 1), acute monocytic (n = 1), acute myelomonocytic (n = 6) and acute undiffer... |
2445561 | Analysis of cytokeratin domains by cloning and expression of intact and deleted polypeptides in Escherichia coli. | Using recombination of an appropriate expression vector system (pINDU) with a complete cDNA encoding a basic (type II) cytokeratin, i.e. cytokeratin 8 (1) of Xenopus laevis, we transformed Escherichia coli cells to synthesize considerable amounts of an insoluble eukaryotic cytoskeletal protein. The cytokeratin was depo... |
2823885 | Molecular recognition between oligopeptides and nucleic acids. Monocationic imidazole lexitropsins that display enhanced GC sequence dependent DNA binding. | A series of monocationic lexitropsins, or information-reading oligopeptides, were synthesized to minimize and offset the AT bias for doubly cationic ligands bound in the minor groove of DNA. The compounds possess an N-formyl group in place of the guanidinium moiety normally present in netropsin. By systematic replaceme... |
3118809 | Factors affecting the production of pyrroloquinoline quinone by the methylotrophic bacterium W3A1. | Two variants of the methylotrophic bacterium W3A1, designated W3A1-S (slimy) and W3A1-NS (nonslimy), were compared with respect to their ability to grow in batch culture on the C1 substrates methylamine, methanol, and trimethylamine. Substrate utilization, cell density, pH, cellular and soluble polysaccharide productio... |
3667839 | Use of chemically-bonded cyclodextrin stationary phase for high performance liquid chromatographic determination of feldene capsules. | A novel high performance liquid chromatographic method (HPLC) is presented for the quantitative determination of piroxicam in capsule formulation (Feldene capsule). Samples are separated on a chemically bonded beta-cyclodextrin column (Cyclobond I) with a mobile phase of 75% 0.05M phosphate buffer (pH 7.0) and 25% meth... |
3665571 | Evidence that fibroblast growth factor promotes lens fibre differentiation. | Lens epithelial cells from newborn rats undergo changes characteristic of fibre differentiation when cultured with rat neural retina or with a soluble mitogenic factor present in calf retina-conditioned medium. Mitogens have been isolated from retina in other laboratories, but have not previously been shown to promote ... |
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