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748682 | Transmembrane interactions and the mechanisms of transport of proteins across membranes. | We have made observations, by double fluorescence staining of the same cell, of the distributions of surface receptors, and of intracellular actin and myosin, on cultured normal fibroblasts and other flat cells, and on lymphocytes and other rounded cells. The binding of multivalent ligands (a lectin or specific antibod... |
748681 | Resistance of the intact and reconstituted adipocyte hexose transport system to irreversible inhibition by sulfhydryl and amino reagents. | Sensitivity of the adipocyte D-glucose transport system in intact plasma membranes or following solubilization and reconstruction into phospholipid vesicles to several protein-modifying reagents was investigated. When intact plasma membranes were incubated with N-ethylmaleimide (20 mM) or fluorodinitrobenzene (4 mM), D... |
219297 | A serological assay for the detection of cell surface receptors of nerve growth factor. | When single-cell suspensions prepared from embryonic day 8 (E8) chick sensory ganglia are incubated with nerve growth factor (NGF), anti-NGF antiserum, and complement, an NGF-dependent cytotoxic kill of 20 (+/- 3)% of the ganglia cells is observed. This percentage is increased by a factor of two when only the neuronal ... |
748680 | Transmembrane action of thrombin initiates chick cell division. | Thrombin immobilized on polystyrene beads initiates DNA synthesis and cell division in quiescent cultures of chick embryo (CE) cells in serum-free medium. These thrombin beads also produce morphological changes in CE cells similar to those produced by soluble thrombin. The amount of acid-precipitable material released ... |
34753 | Cation-dependent phosphatase activites in a rat pancreatic islet plasma membrane fraction prepared by one-step gradient centrifugation. | A plasma membrane-enriched fraction was prepared from homogenized rat pancreatic islets by a one-step sucrose gradient centrifugation. Using 125I-wheat germ agglutinin as a plasma membrane probe, a fraction was obtained at a sucrose density of about 1.10 that was enriched in 5'-nucleotidase, Mg2+-ATPase and alkaline ph... |
219296 | Spin label studies on rat liver and heart plasma membranes: effects of temperature, calcium, and lanthanum on membrane fluidity. | The structures of rat liver and heart plasma membranes were studied with the 5-nitroxide stearic acid spin probe, I(12,3). The polarity-corrected order parameters (S) of liver and heart plasma membranes were independent of probe concentration only if experimentally determined low I(12,3)/lipid ratios were employed. At ... |
748679 | Plasma membrane proteins and glycoproteins from Chinese hamster cells sensitive and resistant to actinomycin D. | Plasma membrane proteins and glycoproteins have been isolated from Chinese hamster cells of the spontaneously transformed DC-3F parental cell line and the DC-3F/AD X line with a high level of acquired resistance to actinomycin D. Plasma membrane preparations from both cell lines band at 1.16 g/ml after isopycnic centri... |
748678 | Membrane effects of imidoesters in hereditary stomatocytosis. | The marked increase in cation (Na+, K+) permeability that results in swollen, cup-shaped red cells in the hereditary stomatocytosis syndrome can be corrected in vitro with a bifunctional crosslinking reagent, dimethyl adipimidate (DMA). 45Ca influx in intact RBC, 45Ca efflux in red ghosts, and 45Ca retention in red gho... |
155181 | Modulator binding protein antagonizes activation of (Ca2+ + Mg2+)-ATPase and Ca2+ transport of red blood cell membranes. | Red blood cells contain a protein that activates membrane-bound (Ca2+ + Mg2+)-ATPase and Ca2+ transport. The red blood cell activator protein is similar to a modulator protein that stimulates cyclic AMP phosphodiesterase. Wang and Desai [Journal of Biological Chemistry 252:4175--4184, 1977] described a modulator-bindin... |
748677 | Binding of ricin A chain to rat liver ribosomes: relationship to ribosome inactivation. | Ricin A chain was radioactively labeled using reductive alkylation, lactoperoxidase catalyzed iodination, and reaction with iodoacetamide or N-ethylmaleimide (NEM). The inhibition of cell-free rat liver protein synthesis by the modified A chains and the ribosome binding characteristics of each of the labeled derivative... |
219295 | An avidin-biotinyl-propranolol complex for beta-adrenergic receptor characterization. | The synthesis of biotinyl-hexaglycyl-NEDA (abbreviation:BGN), a biotinyl derivative of propranolol, is described. This bifunctional molecule binds with high affinity to the biotin-binding protein, avidin. The duck erythrocyte was used as a model beta-receptor system. Formation of an avidin-BGN-beta-receptor complex was... |
748676 | Lipopolysaccharide effects on sensitive and resistant variant Chinese hamster ovary cell lines. | Chinese hamster ovary (CHO . K1 . PRO) cell growth was inhibited by addition of a gram-negative bacterial lipopolysaccharide (LPS) to the cell culture medium. Growth inhibition began after three or four days of incubation, was dose-dependent up to a maximum at an LPS concentration of 500 microgram/ml and was accompanie... |
219294 | The Escherichia coli adenylate cyclase complex: activation by phosphoenolpyruvate. | A model for the regulation of the activity of Escherichia coli adenylate cyclase is presented. It is proposed that Enzyme I of the phosphoenolpyruvate:sugar phosphotransferase system (PTS) interacts in a regulatory sense with the catalytic unit of adenylate cyclase. The phosphoenolpyruvate (PEP)-dependent phosphorylati... |
107369 | Neural uptake of catecholamines and their molecular structures: a histopharmacologic study. | Using ultrastructural and histofluorescence methods, we investigated the uptake mechanism of catecholamines by the nerve terminals in the cutaneous smooth muscles of stump-tailed macaques (Macaca arctoides). This in vivo approach ultilized the observed cytotoxic effects of 6-hydroxydopamine on these catecholamine-conta... |
219293 | Catecholamine binding to CNS adrenergic receptors. | The properties of 3H-catecholamine binding to alpha- and beta-adrenergic receptors in CNS are reviewed. 3H-epinephrine and 3H-norepinephrine label one class of alpha-receptors throughout the brain, with high affinities for agonists and some antagonists. Agonist affinities at this site are increased in low temperature c... |
219292 | Regulation of the receptor-mediated cyclic AMP response of kidney to parathyroid hormone in the vitamin D-deficient rat. | Rats fed a diet deficient in vitamin D were found to exhibit a refractory cyclic AMP response of kidney slices to parathyroid hormone and a marked decrease in membrane parathyroid hormone-dependent adenylate cyclase activity. Both the characteristic calcium deficiency (hypocalcemia) and secondary elevation of circulati... |
748675 | Glycolipids as indicators of tumorigenesis. | Hyperplastic liver nodules and hepatocellular carcinomas were induced in rats by oral administration of the carcinogen N-2-fluorenylacetamide. Neoplastic tissue was compared with control, fetal, neonatal, and precancerous liver tissues. The development of the tumors was slow, such that temporal changes in the biochemic... |
748674 | Independence of normal phenotypic properties and cell surface receptor mobility in variant cell lines. | We report the use of three classes of variants from the long-established, malignantly transformed LM cell line to demonstrate that the apparent mobility of cell surface receptors need not be dependent on the expression of the transformed phenotype in vitro. |
746608 | Axonal transport of horseradish peroxidase: a new method for tracing nervous control of the bladder. | A new method for tracing the nervous control of the bladder is described. A protein substance, horseradish peroxidase, has been shown to be absorbed and transported by nerve fibers. The substance was injected into the bladder neck region of a series of dogs. After uptake by motor neurons the horseradish was carried to ... |
742940 | Subunit structure of Eutherian sperm chromatin. | The beta-mercaptoethanol induced decondensation of spermatozoon cell nuclei from several Eutherian species has been followed from the intact spermatazoon cell to the solubilized linear unit sperm chromosomal fiber using fluorescence and electron microscopy. Data from nuclease digestion studies in conjunction with elect... |
569956 | [Secondary structure of condensed DNA. wide-angle, small-angle x-ray scattering and circular dichroism]. | Ethanol precipitated DNA shows a CD spectrum of the +psi-type which is similar to that of DNA in the A-form. DNA condensed with cetyl-trimethylammonium-bromide shows, depending on the condensation velocity, a CD spectrum of the -psi-type, or a CD spectrum only slightly modified from that of DNA in solution. The first s... |
32438 | Phosphorylation and dephosphorylation of spectrin. | The phosphorylation of spectrin polypeptide 2 is thought to be involved in the metabolically dependent regulation of red cell shape and deformability. Spectrin phosphorylation is not affected by cAMP. The reaction in isolated membranes resembles the cAMP-independent, salt-stimulated phosphorylation of an exogenous subs... |
732312 | Glycophorins A, B, and C: a family of sialoglycoproteins. Isolation and preliminary characterization of trypsin derived peptides. | Two new sialoglycoproteins, glycophorin B and glycophorin C, were isolated from erythrocyte membranes by extraction with lithium diiodosalicylate, partition in aqueous phenol, gel filtration in detergent, and preparative polyacrylamide gel electrophoresis in sodium dodecyl sulfate. The two proteins were characterized b... |
215839 | Glucocorticoid-mediated alteration in growth factor binding and action: analysis of the binding change. | The addition of the glucocorticoid analog dexamethasone (DX) to serum-free cultures of human fibroblasts caused a twofold enhancement of the mitogenic response to epidermal growth factor (EGF), although DX by itself was not mitogenic. A basis for this effect was suggested by studies showing that DX also increased the c... |
215838 | Use of photoaffinity nucleotide analogs to determine the mechanism of ATP regulation of a membrane-bound, cAMP-activated protein kinase. | Using a radioactively tagged, photoaffinity analog of cAMP, 8-azidoadenosine-3',5'-cyclic monophosphate (8-N3 cAMP) and [gamma32P]ATP, the membrane-binding properties of both the regulatory and catalytic subunits of the cAMP-activated protein kinase of human erythrocyte membranes were investigated. [32P]8-N3 cAMP was u... |
732311 | Studies of the diphtheria toxin receptor on Chinese hamster cells. | Concanavalin A, wheat germ agglutinin and the ovalbumin glycopeptide are all inhibitors of the cytotoxic effect of diphtheria toxin on Chinese hamster cells. Ovalbumin glycopeptide loses its inhibitory property after treatment with beta-N-acetylglucosaminidase. This demonstrates the importance of the glycopeptide struc... |
310496 | Mitogenic response to epidermal growth factor: relationship to number, affinity, and down-regulation of EGF receptors in three murine embryo cell lines. | Swiss 3T3 and C3H-M2 cells have a greater mitogenic response to epidermal growth factor (EGF) than do C3H10T 1/2 cells. The latter cell line, however, has a number of EGF receptors per cell intermediate between the two cell lines that have a more vigorous response to EGF. Scatchard analysis of binding data indicate tha... |
743340 | Elucidation of the receptor-bound conformation of the enkephalins. | The biologically relevant conformers of enkephalin predicted by solid state, solution state, and theoretical energy studies have been compared with the published structure-activity data on these compounds. No conformational technique proposes a model consistent with all the pharmacological data; the shortcomings of eac... |
732310 | Properties and action mechanism of the toxic lectin modeccin: interaction with cell lines resistant to modeccin, abrin, and ricin. | The toxic lectin modeccin, which inhibits protein synthesis in eukaryotic cells, is cleaved upon treatment with 2-mercaptoethanol into two peptide chains which move in polyacrylamide gels at rates corresponding to molecular weights 28,000 and 38,000. After reduction, the toxin loses its effect on cells, while its abili... |
153437 | Erythrocyte troponin inhibitor-like protein: isolation and characterization. | A protein was isolated from a human erythrocyte lysate with an apparent molecular weight of 23,000--24,000 daltons. This protein was purified by batch DEAE cellulose followed by column DEAE cellulose chromatography and a gradient of NaCl. On sodium dodecyl sulfate acrylamide electrophoresis, the erythrocyte protein com... |
215837 | Erythrocyte membrane alterations in Huntington disease: effects of gamma-aminobutyric acid. | The interaction of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) with erythrocyte membranes from patients with Huntington disease and normal controls has been studied by electron spin resonance. GABA affects the physical state of erythrocyte membrane proteins in control and Huntington disease different... |
732309 | Actin--membrane interactions: association of G-actin with the red cell membrane. | Chemically tritiated actin from rabbit skeletal muscle was used to investigate the association of G-actin with the red cell membrane. The tritiated actin was shown to be identical to unmodified actin in its ability to polymerize and to activate heavy meromyosin ATPase. Using sealed and unsealed red cell ghosts we have ... |
32437 | Isolation and partial characterization of human erythrocyte membrane NADH: (acceptor) oxidoreductase. | The NADH: (acceptor) oxidoreductase (EC 1.6.99.3) was isolated from human erythrocyte ghosts by a procedure including Triton X-100 solubilization, affinity chromatography on an NAD+-Sepharose 4B column, ammonium sulfate precipitation, and isoelectric focusing. This enzyme preparation was characterized by a single band ... |
215836 | Gycoprotein and protein precursors to plasma membranes in vesicular stomatitis virus infected HeLa cells. | Vesicular stomatitis virus is known to mature at HeLa cell plasma membranes. To study the process, cells, infected with vesicular stomatitis virus, were fractionated after short term labeling studies (1 min pulse, 1 min chase) to determine the assembly kinetics of G protein and M protein into plasma membranes. Newly sy... |
83451 | Dimensions and specificities of recognition sites on lectins and antibodies. | A comparison is made of the specific combining sites of a number of lectins and of antibodies with emphasis on those reacting with blood group A, B, and H determinants. The ranges of site sizes and specificities of both groups are similar both from immunochemical studies and from the limited x-ray diffraction data avai... |
732308 | Sialic acid: a specific role in hematopoietic spleen colony formation. | Vibrio cholerae neuraminidase (VCN) treatment of donor bone marrow cells results in a reduction in the number of hematopoietic colonies (CFUs) formed in the spleens of lethally irradiated mice. Treatment of marrow cells with sodium periodate under mild conditions, known to preferentially oxidize sialic acid, also reduc... |
732307 | Enzymatic conversion of proteins to glycoproteins by lipid-linked saccharides: a study of potential exogenous acceptor proteins. | Previous studies have shown that a membrane preparation from hen oviduct catalyzes transfer of oligosaccharide from oligosaccharide-P-P-dolichol to denatured RNase and alpha-lactalbumin. To gain further insight into the structural requirements of a protein that allow it to serve as a substrate for glycosylation, the ac... |
569744 | Immunochemical purification of probe-labeled plasma membrane proteins: an approach to the molecular anatomy of the cell surface. | The probe 2,4,6-trinitrobenzene sodium sulfonate may be used under appropriate conditions for selective labeling of plasma membrane proteins exposed at the outer cell surface. Labeled proteins, solubilized by detergents, can be purified by reverse immunoadsorption using antiprobe antibodies covalently linked to Sepharo... |
215835 | Cell surface glycosyltransferases--do they exist? | The presence of glycosyltransferases on surfaces of mammalian cells has been reported by many investigators and a biological role for these enzymes in cell adhesion and cell recognition has been postulated. Critical analysis, however, showed 2 major complications regarding the assay for cell surface glycosyltransferase... |
569743 | Direct modification of the glycocalyx of a cultured muscle cell line by incorporation of foreign gangliosides and an integral membrane glycoprotein. | As part of a program to better understand the cause-or-effect nature of the relationship between cell surface carbohydrate and cell properties and behaviour, experiments have been carried out on direct modification of the glycocalyx of cultured cells. Modification was by incorporation of gangliosides and an integral me... |
153436 | Purification and characteristics of hydrophobic membrane protein(s) required for DCCD sensitivity of ATPase in Mycobacterium phlei. | The energy-transducing N,N'-dicyclohexylcarbodiimide-sensitive (DCCD-sensitive) ATPase complex consists of two parts, a soluble catalytic protein (F1), and an intrinsic membrane protein (F0). The bacterial coupling factor complex, BCF0-BCF1, has recently been purified from Mycobacterium phlei, and used to reconstitute ... |
366282 | Ganglioside structures and distribution: are they localized at the nerve ending? | Gangliosides generally provide a small portion of the complex carbohydrate content of cell surfaces. An exception is the central nervous system where they comprise up to 5--10% of the total lipid of some membranes. This tissue is unique in that the quantity of lipid-bound sialic acid exceeds that of the protein-bound f... |
723280 | Effects of abnormal cation transport on deformability of desiccytes. | We have studied the deformability of subpopulations of red cells from a patient with "desiccytosis," a disorder characterized by increased membrane permeability to potassium and associated with a probable increase in sodium-sodium exchange. Cells become increasingly dehydrated after maturation because of continued pota... |
569229 | Metabolic stability of the nucleoside transport system of Novikoff rat hepatoma cells. | Rates of transport of uridine and thymidine, estimated with a rapid sampling technique, did not change with culture age. Inhibition of cellular RNA and protein synthesis for periods up to 6 h, did not lead to a loss of nucleoside transport activity. Mild treatment of cell suspensions with trypsin or neuraminidase had n... |
31515 | Beta-adrenergic receptors: regulatory role of agonists. | Direct radioligand binding studies have been used to probe the molecular mechanisms whereby agonist catecholamines regulate the function of beta-adrenergic receptors in a model system, the frog erythrocyte. The unique characteristics of agonist as opposed to antagonist action are first, the ability to stimulate the ade... |
309973 | Regulation of hemopoietic cell differentiation and proliferation. | Differentiation and proliferation of almost all hemopoietic cell lines can now be studied in vitro. Cloning techniques and suspension cultures allow the study of proliferation of the multipotential hemopoietic progenitor cell and the committed progenitors for granulocytes, macrophages, eosinophils, megakaryocytes, and ... |
214641 | Mechanism of action of choleragen. | Choleragen exerts its effect on cells through activation of adenylate cyclase. Choleragen initially interacts with cells through binding of the B subunit of the toxin to the ganglioside GM1 on the cell surface. Subsequent events are less clear. Patching or capping of toxin on the cell surface may be an obligatory step ... |
723279 | Analysis of the major polypeptides of spectrin by tryptic digestion. | The two major polypeptides of erythrocyte membrane spectrin have been isolated by preparative polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. The tryptic peptide maps of the two polypeptides have been prepared by thin-layer chromatography and electrophoresis. Radioactive peptides have been... |
723278 | Spectrin binding and the control of membrane protein mobility. | Transmembrane proteins of the human erythrocyte show restricted in-plane mobility. Many of the restrictions on mobility are attributable to the molecules of spectrin which are located on the protoplasmic surface of the erythrocyte membrane. These molecules are elongate, form end-to-end heterodimer associations, and bin... |
723277 | Characterization of the glucose transporter from human erythrocytes. | The D-glucose transporter from human erythrocytes has been purified and reconstituted by Kasahara and Hinkle (J Biol Chem 252:7394--7390). Using a similar purification scheme, we have isolated the protein with 65% of the extracted phospholipid at a lipid-protein ratio of 14:1 by weight. The KD (0.14 micrometer) and ext... |
214640 | The program of Friend cell erythroid differentiation: early changes in Na+/K+ ATPase function. | Treatment of Friend erythroleukemia cells with several different chemical agents causes an early decrease in the 86Rb+ influx mediated by Na+/K+ adenosine triphosphatase (ATPase). These agents, which induce Friend cells to differentiate, include dimethylsulfoxide (DMSO), ouabain, hypoxanthine, and actinomycin D. The ma... |
723275 | Influence of increased membrane cholesterol on membrane fluidity and cell function in human red blood cells. | Cholesterol and phospholipid are the two major lipids of the red cell membrane. Cholesterol is insoluble in water but is solubilized by phospholipids both in membranes and in plasma lipoproteins. Morever, cholesterol exchanges between membranes and lipoproteins. An equilibrium partition is established based on the amou... |
723274 | Triton shells of intact erythrocytes. | About 40% of human erythrocyte membrane protein is resistant to solubilization in 0.5% Triton X-114. These components comprise a structure called a Triton shell roughly similar in size and shape to the original erythrocyte and thus constitute a cytoskeleton. With increasing concentrations of Triton the lipid content of... |
723273 | The exchangeability of human erythrocyte membrane cholesterol. | A new method has been used to determine what fraction of human erythrocyte cholesterol is available for exchange with plasma unesterified cholesterol. Erythrocytes labeled with 3H-cholesterol by this exchange process were incubated with sonicated phosphatidylcholine vesicles, giving rise to a net movement of cholestero... |
723272 | Vesicles isolated from ATP-depleted erythrocytes and out of thrombocyte-rich plasma. | When human erythrocytes are depleted of endogenous ATP they release spectrin-free vesicles as a light vesicle fraction [Lutz et al: J Cell Biol 73: 548, 1977] and chains of rounded vesicles as well as flattened myelin forms in a heavy vesicle fraction. The heavy fraction retains some spectrin, and glycophorin is partia... |
723271 | Physical-chemical studies of spectrin. | In recent years considerable progress has been made in the understanding of the structure and function of the red blood cell membrane. The protein spectrin, of high molecular weight and propensity for self-association, appears to play a major role, in concert with actin, in maintaining the shape and integrity of the me... |
723270 | Molecular characteristics of the transferrin-receptor complex of the rabbit reticulocyte. | A macromolecular complex of transferrin and a membrane component was isolated by gel filtration chromatography from Triton X-100-solubilized ghosts of reticulocytes previously incubated with 125I-labeled transferrin. This complex is believed to be transferrin specifically associated with its primary receptors. Followin... |
723269 | Distribution of glycophorin on the surface of human erythrocyte membranes and its association with intramembrane particles: an immunochemical and freeze-fracture study of normal and En(a-) erythrocytes. | Human erythrocyte membranes of the En(a-) blood group lack the major sialoglycoprotein (glycophorin). By absorption of a crude antiglycophorin antiserum with En(a-) membranes a specific antiglycophorin antiserum was obtained. By immune electron microscopy we showed that glycophorin is randomly distributed on the surfac... |
723268 | Fine structure of the band 3 protein in human red cell membranes: freeze-fracture studies. | The major red cell membrane protein, band 3, is a glycoprotein which extends across the membrane from the extracellular space into the cytoplasmic compartment. It is widely held that band 3 is a component of the intramembrane particles (IMP) which can be demonstrated by freeze-fracture electron microscopy. In this stud... |
364194 | The band 3 protein of the human red cell membrane: a review. | Band 3 is the predominant polypeptide and the purported mediator of anion transport in the human erythrocyte membrane. Against a background of minor and apparently unrelated polypeptides of similar electrophoretic mobility, and despite apparent heterogeneity in its glycosylation, the bulk of band 3 exhibits uniform and... |
723267 | Membrane permeability of bifunctional, amino site-specific, cross-linking reagents. | The membrane permeability of a series of reversible cross-linking reagents which are diazide tartarate derivatives has been compared with that of dimethyl-3,3'-dithiobispropionimidate (DTBP). The diazide tartarate derivatives tested include tartryl-diazide (TDA), tartryl-di(glycylazide) (TDGA), tartryl-di(beta-alanylaz... |
723266 | Characterization of the ribosomal binding site in rat liver rough microsomes: ribophorins I and II, two integral membrane proteins related to ribosome binding. | Rat liver rough endoplasmic reticulum membranes (ER) contain two characteristic transmembrane glycoproteins which have been designated ribophorins I and II and are absent from smooth ER membranes. These proteins (MW 65,000 and 63,000 respectively) are related to the binding sites for ribosomes, as suggested by the foll... |
723265 | Retention of insulin-stimulated D-glucose transport activity by adipocyte plasma membranes following extraction of extrinsic proteins. | Plasma membrane vesicles prepared from adipocytes incubated with insulin exhibited accelerated D-glucose transport activity characteristic to insulin action on intact fat cells. Both control and insulin-stimulated D-glucose transport activities were inhibited by cytochalasin B and thiol reagents. Extraction of plasma m... |
309972 | Mitogens for murine embryo cell lines. | The growth-promoting activities of fetal bovine serum, cortisol, phorbol myristate acetate, prostaglandin F2alpha, insulin, epidermal growth factor, and fibroblast growth factor were evaluated on four murine embryo cell lines (Swiss 3T3, Balb 3T3, M2, and C3H10T 1/2). Each cell has an unique response spectrum to this c... |
82677 | Existence of a common precursor to ACTH and endorphin in the anterior and intermediate lobes of the rat pituitary. | Extracts of rat anterior and intermediate-posterior pituitary were fractionated by sodium dodecyl sulfate polyacrylamide gel electrophoresis and assayed for immunoactive ACTH and endorphin. In both lobes the major forms of immunoactive ACTH have apparent molecular weights of 31,000 (31K), 20--21K, 14K, and 4.5K, and th... |
214639 | Inhibition of the binding of low-density lipoprotein to its cell surface receptor in human fibroblasts by positively charged proteins. | A group of proteins and polyamino acids with positively charged domains were shown to inhibit the binding of 125I-LDL to its receptor on the surface of human fibroblasts. The list of inhibitory proteins included platelet factor 4 (which has a cluster of lysine residues at its carboxyl terminus), two lysine-rich histone... |
540611 | Environmental contaminants and intestinal function. | THE ENVIRONMENTAL CONTAMINANTS WHICH HAVE THEIR MAJOR EFFECTS ON THE SMALL INTESTINE MAY BE CLASSIFIED INTO FIVE MAJOR CATEGORIES: (1) bacterial, viral, and parasitic agents, (2) food and plant substances, (3) environmental and industrial products, (4) pharmaceutical agents, and (5) toxic agents whose metabolic effects... |
293709 | Semisynthesis of human somatotropin analogs. | Complementation of the natural NH2-terminal 134-amino acid fragment of the reduced, carbamoylmethylated human somatotropin with synthetic analogs of COOH-terminal fragments of 57, 42, or 38 amino acids of reduced, carbamoyl-methylated human somatotropin has been investigated. It was found that synthetic fragments of 57... |
521456 | Evidence for rapid structural and functional changes of the melanophore microtubule-organizing center upon pigment movements. | Melanophores of the angelfish, pterophyllum scalare, have previously been shown to display approximately 2,400 microtubules in cells wih pigment dispersed; these microtubules radiate from a presumptive organizing center, the central apparatus (CA), and their number is reduced to approximately 1,000 in the state with ag... |
44705 | Quantitation of the adherence of an enteropathogenic Escherichia coli to isolated rabbit intestinal brush borders. | Two assays were developed to quantitate the adherence of an Escherichia coli strain (RDEC-1) known to colonize the mucosal surface of the small intestine of rabbits to brush borders isolated from rabbit intestinal epithelial cells. In the first assay, the mean adherence per rabbit brush border was determined by countin... |
534500 | Purification of fibronectin from human plasma by affinity chromatography under non-denaturing conditions. | Fibronectin was purified from human plasma by affinity chromatography under nondenaturing conditions. The method was based on the previously known binding of fibronectin to gelatin. The novel features of our method are the use of arginine in the elution of fibronectin from immobilized gelatin [Vuento & Vaheri (1978) Bi... |
160555 | Dynein binds to and crossbridges cytoplasmic microtubules. | Dynein isolated from Chlamydomonas flagellar axonemes binds to microtubules assembled in vitro from 6S brain tubulin dimers. The dynein arms bind periodically along the length of the microtubules with a center-to-center spacing of 24 nm, equal to the periodicity of dynein arms on intact axonemes. The arms project from ... |
293678 | Purification of cytoplasmic tubulin and microtubule organizing center proteins functioning in microtubule initiation from the alga Polytomella. | Cytoplasmic tubulin and the microtubule organizing centers (MTOCs) for the cytoskeletal microtubule system of the flagellate Polytomella have been isolated. The isolated MTOCs serve as sites for the in vitro assembly of the purified tubulin protein. The major proteins (four polypeptides of molecular weights 190,000-210... |
574640 | Spermine-DNA complexes build up metastable structures. Small-angle X-ray scattering and circular dichroism studies. | Spermine-DNA complexes have been examined by small-angle and wide-angle X-ray scattering as well as by circular dichroism studies. Condensed complexes are building up below a critical ionic strength. We have found that at one and the same ionic strength condensed complexes having two different supramolecular structures... |
388358 | RNA-linked nascent DNA pieces in phage T7-infected Escherchia coli. II. Primary structure of the RNA portion. | Short DNA chains were purified from phage T7 infected E. coli cells and 5' ends were labeled with 32P. By an alkali-treatment, pNp's rich in pAp and pCp were liberated from the T7 short DNA chains. After digestion of the [5'-32P] short DNA with the 3' to 5' exonuclease of T4 DNA polymerase, [5'-32P] mono- to pentaribon... |
91653 | Binding of purified, soluble major histocompatibility complex polypeptide chains onto isolated T-cell receptors. I. Reactivity against allo- and self-determinants. | In this study, we tried to get information about the fine antigen-binding ability of purified, soluble, idiotype-positive T-cell receptor molecules. Lewis anti-DA T-cell receptors were purified from normal Lewis serum by the use of anti-idiotypic immunosorbent and sodium dodecyl sulfate-polyacrylamide gel, and were cou... |
227913 | Involvement of microtubules and 10-nm filaments in the movement and positioning of nuclei in syncytia. | Previous studies (Holmes, K.V., and P.W. Choppin. J. Exp. Med. 124:501-520; J. Cell Biol. 39:526-543) showed that infection of baby hamster kidney (BHK21-F) cells with the parainfluenza virus SV5 causes extensive cell fusion, that nuclei migrate in the syncytial cytoplasm and align in tightly-packed rows, and that micr... |
16592716 | Sulfur base ligation to iron(II) and cobalt(II) porphyrins. | Equilibrium constants for the binding of sulfur bases to cobalt(II) porphyrins were measured in toluene solution by a spectrophotometric method. The order of decreasing binding strength of sulfur ligands to cobalt(II) porphyrins was found to be mercaptide ions >> thioethers > mercaptans. It is suggested that a similar ... |
92516 | Inhibition of H-Y cell-mediated cytolysis by H-2Db antiserum. | Assays of H-Y-specific cell-mediated cytolysis (CMC) in vitro were carried out with B6 female effector cells and B6 male target cells. This lytic system depends on compatibility for H-2Db but not for H-2Kb. Antibody to H-2Db but not to H-2Kb blocked the CMC assay. However, maximal blocking required exposure to the targ... |
512582 | H-Y antigen. Cell surface mapping and testosterone-induced supramolecular repatterning. | Previous work with the antibody-blocking technique showed that the map of surface components for thymocytes prefixed with paraformaldehyde is the same as the map for unfixed thymocytes, with the following exception: after exposure to anti-TL or anti-Db, TL and H-2Db occupy adjacent positions on unfixed cells but not on... |
511939 | Characteristics of the polar assembly and disassembly of microtubules observed in vitro by darkfield light microscopy. | We describe here the continuous observations of the polymerization of individual microtubules in vitro by darkfield microscopy. In homogeneous preparations we verify that polymerization can occur onto both ends of microtubules. The assembly of microtubules is polar, with one end growing at three times the rate of the o... |
228284 | Enzyme therapy in Fabry disease: differential in vivo plasma clearance and metabolic effectiveness of plasma and splenic alpha-galactosidase A isozymes. | A pilot trial of enzyme replacement with splenic and plasma alpha-galactosidase A (alpha-D-galactosidase; alpha-D-galactoside galactohydrolase, EC 3.2.1.22) isozymes was undertaken in two brothers with Fabry disease, an X-linked glycosphingolipid storage disease. Six unentrapped doses (2000 units/kg) of each isozyme we... |
18962548 | Extraction of alkali metal picrates with poly- and bis(crown ether)s. | Extraction of alkali metal picrates by new poly- and bis(crown ether)s containing benzo-15-crown-5 and benzo-18-crown-6 moieties was carried out with chloroform as water-immiscible solvent. The poly- and bis(crown ether)s were found to extract the picrates more effectively than the corresponding monocyclic crown ethers... |
18962544 | Photometric reagents for alkali metal ions, based on crown-ether complex formation--III. 4'-picrylaminobenzo-15-crown-5 derivatives. | An extraction study of alkali metal cations has been made with crown-ether reagents, 4'-picrylaminobenzo-15-crown-5 derivatives (HL). On dissociation in alkaline medium, the orange HL gives the blood-red anion L(-) and extracts alkali metal ions into chloroform as coloured complexes of composition ML.HL or ML. The ease... |
387724 | Role of gene flaFV on flagellar hook formation in Salmonella typhimurium. | Nine temperature-sensitive nonflagellate mutants defective in flaFV were isolated from a strain of Salmonella typhimurium. Among them three mutants were found to produce flagella with abnormally shaped (either straight or irregularly curved) hooks at the permissive temperature. Two mutations that rendered hooks straigh... |
91584 | Behavior of a surface antigenic determinant of lateral flagella of Vibrio parahaemolyticus. | The behavior of a surface antigenic determinant (SA) of lateral flagella of Vibrio parahaemolyticus was studied. SA, located on the surface of flagellar filaments, is responsible for H-agglutination and specific for serotype. Results of H-agglutination inhibition tests demonstrated that SA could not be detected on the ... |
387605 | Modulation of the immune response to sheep erythrocytes by lipid-free glycerol teichoic acid. | The 4-day response of C3H/HeJ mice to sheep erythrocytes was suppressed by a lipid-free teichoic acid with an average molecular weight of 2,900 when it was administered by the intraperitoneal route. Enhancement was not observed at that time, and neither suppression nor enhancement could be demonstrated by the intraveno... |
495691 | Lung injury induced by leukocytic proteases. | Human polymorphonuclear neutrophilic leukocytes (PMNs) contain large amounts of neutral proteases that can degrade elastin, collagen, proteoglycan, and basement membrane. The instillation of one of the purified enzymes (elastase) into dog lungs in vivo causes degradation of elastic fibers and other alveolar septal comp... |
39676 | Purification and physiocochemical properties of an extra-cellular cycloamylose (cyclodextrin) glucanotransferase from Bacillus macerans. | An extracellular cycloamylose (cyclodextrin) glucanotransferase (EC 2.4.1.19) from Bacillus macerans was purified to homogeneity by adsorption on starch, ammonium sulfate fractionation, column chromatography on DEAE-cellulose, and gel filtration on Sephadex G-100. The enzyme had a molecular weight of 67,000 and consist... |
228773 | [Structural changes of synaptic membranes under the action of specific antisera using the spin probe technique]. | The spin probing technique was used to study the interaction of preparations of rat cerebral cortex synaptic membranes with specific antisera. It was found that the fluidity of membrane matrix largely depended on the nature of physiological processes involving synaptic membranes in vivo. The supramolecular structure of... |
291973 | Protein-heme interaction in hemoglobin: evidence from Raman difference spectroscopy. | Raman difference spectroscopy measurements on native and chemically modified human deoxyhemoglobins stabilized in either the R or the T quaternary structure revealed frequency differences in the oxidation state marker lines. The differences indicate that the R structure has an effective increase in the electron density... |
582885 | Current status of multichannel cochlear protheses. | Multichannel cochlear prostheses are being developed and evaluated with emphasis on providing sensory deaf individuals enough information about their acoustic environment to permit communication by ordinary speech. Studies of the safety of the electrode arrays and stimulus values indicate that the remaining nerve fiber... |
117749 | Inhibitory effects of carcinogenic mycotoxins on deoxyribonucleic acid-dependent ribonucleic acid polymerase and ribonuclease H. | Fourteen mycotoxins were tested for inhibitory effects on ribonucleic acid polymerase of rat liver and Escherichia coli and nuclear ribonuclease H of rat liver and Tetrahymena pyriformis. These enzymes were strongly inhibited by (-)-luteoskyrin, (+)-rugulosin, patulin, and PR toxin. |
574079 | Some aspects on the organization of microfilaments and microtubules in relation to nondisjunction. | One possible mechanism behind nondisjunction is a malfunctioning spindle. A defect or lack of spindle is a criterion for c-mitosis. In chemical mutagenesis research the c-mitotic effect is a well known cytological phenomemon, which can be induced by many different compounds. Pioneer work was performed during the 1940's... |
115008 | Mutation in a structural gene for a beta-tubulin specific to testis in Drosophila melanogaster. | By two-dimensional gel electrophoresis of tubulins prepared from tissues of Drosophila melanogaster we have identified a beta-tubulin subunit that is present only in the testis. Furthermore, we have isolated, as a male sterile, a third chromosome dominant mutation [ms(3)KKD] in the structural gene for this beta-tubulin... |
226984 | Protein influence on the heme in cytochrome c: evidence from Raman difference spectroscopy. | Raman difference spectra have been obtained for the cytochromes c of a number of species by simultaneous data acquisition from two samples. Frequency differences as small as 0.1 cm-1 can be measured reproducibly by the technique we have developed. In comparisons between cytochromes c isolated from two different species... |
480163 | Improvements of dissolution characteristics and chemical stability of 16,16-dimethyl-trans-delta 2-prostaglandin E1 methyl ester by cyclodextrin complexation. | Inclusion complexation of 16,16-dimethyl-trans-delta 2-prostaglandin E1 methyl ester (I), which is effective in early pregnancy termination, with cyclodextrins in water was ascertained by a solubility study. A solid complex of I-beta-cyclodextrin in a 1:2 molar ratio was obtained, and its dissolution behavior and chemi... |
479317 | Microtubule initiation at kinetochores and centrosomes in lysed mitotic cells. Inhibition of site-specific nucleation by tubulin antibody. | A lysed cell system was developed to determine whether tubulin antibody can block the nucleation of exogenous tubulin at kinetochores and centrosomes. Mitotic PtK2 cells were pretreated with colcemid to remove all endogenous microtubules and were lysed with Triton X-100 in PIPES-EGTA-Mg++ buffer. This procedure left ce... |
479316 | Micromanipulation studies of chromosome movement. II. Birefringent chromosomal fibers and the mechanical attachment of chromosomes to the spindle. | The degree of mechanical coupling of chromosomes to the spindles of Nephrotoma and Trimeratropis primary spermatocytes varies with the stage of meiosis and the birefringent retardation of the chromosomal fibers. In early prometaphase, before birefringent chromosomal fibers have formed, a bivalent can be displaced towar... |
458378 | Radioimmune analysis of an unexpected mouse allotype. | We have used a radioimmune assay to confirm our earlier findings of an unexpected immunoglobulin allotype in Igb-congenic BALB/c mice. Although these mice were bred to exclude the IgG2a allotype of BALB/c (Ig-la), an Ig-la-like antigen was detected in the 7S Ig fraction of two (of five) pooled serum samples, it represe... |
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