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544926 | Ganglioside patterns of metastatic and non-metastatic transplantable hepatocellular carcinomas of the rat. | In previous investigations, we correlated levels of sialic acid, gangliosides, and ganglioside glycosyltransferases with tumorigenesis over a 24-week continuum of growth of hepatocellular neoplasms of the rat induced by the carcinogen N-2-fluorenylacetamide. However, metastatic tumors developed only rarely and were not... |
232522 | Cholesterol levels and plasma membrane fluidity in 3T3 and SV101-3T3 cells. | Polyene antibiotics such as filipin selectively inhibit wheat germ agglutinin-induced agglutination of transformed and malignant cells compared to normal cells (Hatten ME, Burger MM: Biochemistry 18: 739, 1979). Since filipin binds specifically to cholesterol, we measured cholesterol levels in 3T3 cells and SV101-3T3 c... |
544925 | Growth rate and chromosome number of tumor cell lines with different metastatic potential. | We investigated whether the metastatic potential of various tumor cell lines was related to chromosome counts or to rate of growth in vitro or in vivo. Clones of known metastatic potential derived from a C3H- fibrosarcoma induced by UV radiation (UV-2237) and from C57BL/6 B16 melanoma were tested for these characterist... |
44535 | Alkaline phosphatase of basal lateral and brush border plasma membranes from intestinal epithelium. | The alkaline phosphatase present on isolated brush border and basal lateral membranes of rat duodenal epithelium were examined by means of a variety of biochemical assays and physical methods. The two alkaline phosphatases have similar pH optima of 9.6--9.8, similar substrate km's for p-nitrophenyl phosphate (PNPP) of ... |
544924 | Subcellular fractionation of brown adipose tissue. | The present study proposes a technique, using Metrizamide, which permits the preparation of brown adipose tissue plasma membranes from the crude mitochondria as well as from the crude microsome fraction. These plasma membranes have high relative specific activities of their marker enzyme, 5'-nucleotidase (15 +/- 3 and ... |
44534 | Effect of phospholipase A2 on purified gastric vesicles. | The phospholipid and fatty acid composition and role of phospholipids in enzyme and transport function of gastric (H+ + K+)-ATPase vesicles was studied using phospholipase A2 (bee venom). The composition (%) was phosphatidyl-choline (PC) 33%; sphingomyelin (sph) 25%; phosphatidylethanolamine (PE) 22%; phosphatidylserin... |
232521 | Fibronectin and proteoglycans as determinants of cell-substratum adhesion. | When normal or SV40-transformed Balb/c 3T3 cells are treated with the Ca++-specific chelator EGTA, they round up and pull away from their footpad adhesion sites to the serum-coated tissue culture substrate, as shown by scanning electron microscope studies. Elastic membranous retraction fibers break upon culture agitati... |
232520 | Isolation and immunological characterization of an iron-regulated, transformation-sensitive cell surface protein of normal rat kidney cells. | We have analyzed the surfacr proteins of cultured normal rat kidney (NRK) cells and virus-transformed NRK cells subjected to iron deprivation. Such a treatment specifically induces two transformation-sensitive plasma membrane-associated glycoproteins with a subunit molecular weight of 160,000 (160 K) and 130,000 (130 K... |
544923 | Stimulation of human vascular endothelial cell growth by a platelet-derived growth factor and thrombin. | Repair of a vascular wound is mediated by migration and subsequent replication of the endothelial cells that form the inner lining of blood vessels. We have measured the growth response of human umbilical vein endothelial cells (HuE) to two polypeptides that are transiently produced in high concentrations at the site o... |
544922 | The serum-free growth of Balb/c 3T3 cells in medium supplemented with bovine colostrum. | Bovine milk contains growth promoting factors that stimulate DNA synthesis and cell division in confluent monolayers of quiescent Balb/c 3T3 cells. The growth factor activity was highest in colostrum obtained within 24 hours after birth of a calf. Samples of milk obtained 32 hours and 60 hours after birth were 20% and ... |
120905 | Effect of vanadate on gill cilia: switching mechanism in ciliary beat. | Lateral (L) cilia of freshwater mussel (Margaritana margaritifera and Elliptio complanatus) gills can be arrested in one of two unique positions. When treated with 12.5 mM CaCl2 and 10(-5) M A23187 they arrest in a "hands up" position, ie, pointing frontally. When treated with approximately 10 mM vanadate (V) they arre... |
544921 | Pyrenesulfonyl azide as a fluorescent label for the study of protein-lipid boundaries of acetylcholine receptors in membranes. | Acetylcholine receptor (AcChR) enriched membrane fragments from Torpedo californica electroplax were labeled by in situ photogenerated nitrenes from a hydrophobic fluorescent probe, pyrene-1-sulfonyl azide. Preferential photolabeling of membrane proteins, mainly AcChR, has been achieved and there is a pronounced exposu... |
544920 | Fibrous projections from the core of a bacteriophage T7 procapsid. | A cylindrical core previously demonstrated in a bacteriophage T7 procapsid (capsid I) has been further examined by electron microscopy. Fibrous extensions of the core have been observed; these fibers appear to connect the core to the capsid I envelope. After infection of a nonpermissive host with bacteriophage T7 amber... |
161791 | Polypeptide subunits of dynein 1 from sea urchin sperm flagella. | A high-resolution sodium dodecyl sulfate polyacrylamide gel electrophoresis system has been used to show the presence, in both whole sperm and isolated flagellar axonemes, of eight polypeptides migrating in the 300,000--350,000 molecular weight range characteristic of the heavy chains of dynein ATPase. Previously, only... |
575662 | Threshold effects on the lectin-mediated aggregation of synthetic glycolipid-containing liposomes. | Cholesterol analogs containing sugar residues linked by spacer groups to the cholesterol O can be incorporated into egg yolk lecithin small unilamellar liposomes. The synthetic glycolipid analogs distribute evenly on both sides of the bilayer. These liposomes are aggregated by the appropriate lectin. For example, when ... |
583496 | Specific interaction of cytochalasins with muscle and platelet actin filaments in vitro. | The cytochalasins (CE, CD, CB and H2CB) inhibit numerous cellular processes which require the interaction of actin with other structural and contractile proteins. In this report we describe the effects of the cytochalasins on the viscosity and morphology of muscle and platelet actin. The cytochalasins decreased the vis... |
522486 | Cell surface fibronectin and oncogenic transformation. | Fibronectin is a large glycoprotein at the cell surface of many different cell types; a related protein is present in plasma. Fibronectin is a dimer of 230,000-dalton subunits and also occurs in larger aggregates; it forms fibrillar networks at the cell surface, between cells and substrata and between adjacent cells, a... |
118307 | Co-translational modification of nascent immunoglobulin heavy and light chains. | We have investigated the in vivo co-translational covalent modification of nascent immunoglobulin heavy and light chains. Nascent polypeptides were separated from completed polypeptides by ion-exchange chromatography of solubilized ribosomes on QAE-Sephadex. First, we have demonstrated that MPC 11 nascent heavy chains ... |
522485 | Synergistic stimulation of early events and DNA synthesis by phorbol esters, polypeptide growth factors, and retinoids in cultured fibroblasts. | 12-O-Tetradecanoyl-phorbol-13-acetate (TPA), in the absence of serum, acts synergistically with a range of polypeptide growth factors to stimulate DNA synthesis in quiescent Swiss 3T3 cells. These growth factors include epidermal growth factor (EGF), insulin, and the peptide produced by BHK cells transformed by SV-40 v... |
522483 | Extracellular lectin and its glycosaminoglycan inhibitor in chick muscle cultures. | Embryonic chick muscle contains two developmentally regulated lectins, which may be involved in cell interactions. These endogenous lectins are assayed as agglutinins of appropriate test erythrocytes. One of these, called lectin-2, interacts with specific glycosaminoglycans, especially heparin and dermatan sulfate. Lec... |
230391 | Endogenous cyclic AMP does not modulate transport of hexoses, nucleosides, or nucleobases in Chinese hamster ovary cells. | In a previous study we have demonstrated that neither extracellular nor intracellular cyclic adenosine monophosphate (AMP) levels directly affect the uptake of nucleosides, nucleobases, or hexoses by various types of cultured mammalian cells. Uptake of these nutrients into cells, however, involves two processes operati... |
230390 | Flow cytometry analysis of early DNA content changes in human and monkey cells following infection with Simian Virus 40. | Simian virus 40 (SV40) is capable of inducing cellular DNA synthesis in permissive and nonpermissive cells. Utilizing flow cytometry, we analyzed the DNA content changes in two diploid human cell strains and two monkey cell lines. The osteogenesis imperfecta (OI) human skin fibroblasts were induced into DNA synthesis, ... |
522481 | Tumor metastases and cell-mediated immunity in a model system in DBA/2 mice. VIII. Expression and shedding of Fc gamma receptors on metastatic tumor cell variants. | The expression of receptors for the Fc portion of IgG immunoglobin molecules was studied on tumor cell lines with high and low metastatic capacity. Two tumor cell lines from DBA/2 mice that had high metastatic activity, ESb and MDAY-D2, contained a high percentage of Fc receptor positive cells, as detected in a rosette... |
230389 | Detection of erythrocyte membrane structural abnormalities in lecithin: cholesterol acyltransferase deficiency using a spin label approach. | The membrane fluidity of erythrocytes from patients with Lecithin: cholesterol acyltransferase (LCAT) deficiency was studied by means of electron spin resonance. The temperature dependence of the separation of the outer extrema of the spectra of 2-(3-carboxy-propyl)-4,4-dimethyl, 2-tridecyl-3-oxazolidinyloxyl spin prob... |
118241 | Anti-riboflavin activity of 8-O-alkyl derivatives of riboflavin in some Gram-positive bacteria. | Two new 8-O-alkyl derivatives of riboflavin (RF), i.e., 8-methoxy- (MOF), and 8-ethoxy-8-demethyl-D-riboflavin (EOF), their tetraacetate, and the tetraacetate of 8-hydroxy-8-demethyl-D-riboflavin (HOF) were synthesized. The anti-RF activity of MOF, EOF and HOF was estimated from the ratio CR/CI, where CI is the concent... |
229358 | Preliminary molecular replacement results for a crystalline gene 4 protein-deoxyoligonucleotide complex. | Complexes of the gene 5 protein from bacteriophage fd with a variety of oligodeoxynucleotides, ranging in length from two to eight and comprised of several different sequences, have been formed and crystallized for X-ray diffraction analysis. The crystallographic parameters of four different unit cells, all of which ar... |
229357 | Reconstituted low density lipoprotein: a vehicle for the delivery of hydrophobic fluorescent probes to cells. | Previous studies have shown that the cholesteryl ester core of plasma low density lipoprotein (LDL) can be extracted with heptane and replaced with a variety of hydrophobic molecules. In the present report we use this reconstitution technique to incorporate two fluorescent probes, 3-pyrenemethyl-23, 24-dinor-5-cholen-2... |
229356 | Structure of the DNA binding cleft of the gene 5 protein from bacteriophage fd. | The structure of the gene 5 DNA unwinding protein from bacteriophage fd has been solved to 2.3-A resolution by X-ray diffraction techniques. The molecule contains an extensive cleft region that we have identified as the DNA binding site on the basis of the residues that comprise its surface. The interior of the groove ... |
92615 | The accessibility of antigenic determinants of ribosomal protein S4 in situ. | Antibodies to Escherichia coli ribosomal protein S4 react with S4 in subribosomal particles, eg, the complex of 16S RNA with S4, S7, S8, S15, S16, S17, and S19 and the RI reconstitution intermediate, but they do not react with intact 30S subunits. Antibodies were isolated by three different methods from antisera obtain... |
159982 | Phosphorprotein intermediate in the Ca2+-dependent ATPase reaction of macrophage plasma membrane. | ATPase activity and phosphorylation by [gamma-32P] ATP of isolated plasma membrane of alveolar macorphages are stimulated in a parallel fashion by physiologic concentrations of Ca2+, with half-maximal activating effect of this ion at (3--7) X 10(-7) M. For various membrane preparations, a direct proportionality exists ... |
513771 | Tubulin rings: curved filaments with limited flexibility and two modes of association. | Tubulin rings have been previously identified as composed of linear polymers of tubulin subunits, equivalent to a protofilament in the microtubule wall but in a curved rather than a straight conformation. We have examined and measured a number of different ring structures obtained under different conditions. The prefer... |
513770 | Comparison of the major polypeptides of the erythrocyte nuclear envelope. | The three most abundant nonhistone polypeptides (molecular weights 75,000, 71,000 and 61,000) of the avian erythrocyte nucleus have previously been isolated in the nuclear envelope fraction. They have been separated by sodium dodecylsulfate-polyacrylamide gel electrophoresis and peptide-mapped after limited enzymatic d... |
390251 | Structure of functional A salina -- E coli hybrid ribosome by electron microscopy. | Small 40S Artemia salina and large 50S Escherichia coli ribosomal subunits can be assembled into 73S hybrid monosomes active in model assays for protein synthesis. The reciprocal combination -- small 30S E coli and large 60S A salina -- fails to form hybrids. The 73S hybrid particles strongly resemble homologous 70S E ... |
117265 | Superstructures of wet inactive chromatin and the chromosome surface. | Superpacking of chromatin and the surface features of metaphase chromosomes have been studied by SiO replication of wet, unstained, and unfixed specimens in an exceedingly thin (less than or equal to nm) aqueous layer, keeping them wet. Hydrophilic Formvar substrates allow controlled thinning of the aqueous layer cover... |
573829 | Ribosome crystallization in nuclei of chick embryos. | Ribosome crystallization within nuclei has been studied in chick embryos with procedures which increase its frequency by various orders of magnitude as compared to previous findings. The extrusion of ribosome microcrystals from nuclei is reported for the first time, and a model for the transfer of ribosomes from nucleu... |
573828 | The role of temperature in the crystallization of ribosomes in chick embryos. | The relationship between ribosome crystallization and cell degeneration has been studied in chick embryos at various temperatures, and new methods of inducing ribosome microcrystals are described. A model is discussed that reinterprets the role of low temperatures in these phenomena and provides a unitary explanation o... |
573827 | Ribosome crystallization in homogenates and cell extracts of chick embryos. | Ribosome microcrystals have been obtained for the first time in homogenates and extracts of chick embryos mainly in the form of P422 stacks that have average linear dimensions some 40% greater than those obtained in vivo. |
158681 | Relationship between steps in 8-anilino-1-naphthalene sulfonate (ANS) fluorescence and changes in the energized membrane state and in intracellular and extracellular adenosine 5'-triphosphate (ATP) levels following bacteriophage T5 infection of Escherichia coli. | The addition of bacteriophage T5 to anaerobic, fermenting cells of Escherichia coli B or K-12 in the presence of 8-anilino-1-naphthalene sulfonate (ANS), N-phenylnaphthyl-1-amine (NPN), or dansyl ethylamine causes the fluorescence of these probes to rise in two steps, the first occurring immediately upon addition, the ... |
491660 | Regulation of the cell cycle of 3T3 cells in culture by a surface membrane-enriched cell fraction. | Addition of a suspension of a surface membrane enriched fraction prepared from confluent 3T3 cells to sparse 3T3 cells in culture results in a concentration dependent and saturable decrease in the rate of DNA synthesis. The inhibition of cell growth by membranes resembles the inhibition of cell growth observed at confl... |
491659 | Characterization of antigenic sialoglycoprotein subunits of the placental brush border membranes: comparison with liver and kidney membrane subunits by two-dimensional electrophoresis. | The sialoglycoprotein subunits of human placental brush border membranes were labeled by sequential treatment with periodate and (3H)-sodium borohydride, which trititates sialic acid, and by lactoperoxidase-catalyzed (125I) iodination of tyrosine residues. The labeled subunits were characterized with respect to their a... |
226805 | Lipid-protein interactions in membranes: effect of lipid composition on mobility of spin-labeled cysteine residues in yeast plasma membrane. | In order to gain direct evidence for lipid-dependent protein conformation in membrane, effects of modification of lipid composition on mobility of spin-labeled cysteine residues were investigated in the plasma membrane of the yeast Saccharomyces cerevisiae. Conversion of the bulk of phospholipids to diglycerides by tre... |
112825 | Alteration of the enucleating erythroblast glycocalyx. | Plasmalemmal differentiation of the enucleating normoblast of rabbit and rat was studied by means of cytochemical methods and freeze-etching. Staining with colloidal iron revealed about identical amounts of iron particles bound to various areas of the normoblast membrane. Cationized ferritin and ruthenium red, likewise... |
461181 | Rapid synthesis of oligodeoxyribonucleotides on a grafted polymer support. | Rapid synthesis of oligodeoxyribonucleotides is described by a solid phase method. Polysterene grafted on the surface of polytetrafluoroethylene has been found to be an adequate support. The properties of the support were studied in the synthesis of a number of oligonucleotides 6 to 15 nucleotides long. A flow-type sem... |
459513 | Role of bound water in biological membrane structure: fluorescence and infrared studies. | Bound water is a major component of biological membranes and is required for the structural stability of the lipid bilayer. It has also been postulated that it is involved in water transport, membrane fusion, and mobility of membrane proteins and lipids. We have measured the fluorescence emission of membrane-bound 1-an... |
222969 | Erythrocyte spectrin alteration induced by low-density lipoprotein. | Addition of human plasma low-density lipoproteins (LDL) to intact human erythrocytes induces the erythrocytes to undergo morphologic transition from biconcave disks to echinocytes and spherocytes. The transformation is time-dependent. Two hours are required before echinocytes are detected by scanning electron microscop... |
222968 | Interaction between glycophorin and phospholipids in recombined systems. | Both the MN-glycoprotein from human erythrocytes and the hydrophobic fragment from the protein isolated with trypsin treatment, T(is), have been recombined with egg phosphatidylcholine in bilayers at various phospholipid/protein ratios. In order to investigate the effect of the protein on the phospholipid headgroups, 3... |
459512 | Substructure of human erythrocyte spectrin. | The human erythrocyte structural protein spectrin and its subunits I, II were isolated in the presence of Na-dodecyl-sulfate by gel filtration and preparative gel electrophoresis. After removal of the detergent, spectrin alpha-helical content is comparable to spectrin isolated without detergent. Subunits I and II forme... |
156819 | Properties of (Mg2 + Ca2+)-ATPase of erythrocyte membranes prepared by different procedures: influence of Mg2+, Ca2+, ATP, and protein activator. | Erythrocyte membranes prepared by three different procedures showed (Mg2+ + Ca2+)-ATPase activities differing in specific activity and in affinity for Ca2+. The (Mg2+ + Ca2+)-ATPase activity of the three preparations was stimulated to different extents by a Ca2+-dependent protein activator isolated from hemolysates. Th... |
313483 | Internalization and processing of the EGF receptor in the induction of DNA synthesis in cultured fibroblasts: the endocytic activation hypothesis. | The addition of EGF to cultured murine 3T3 cells produces a decrease in EGF binding activity with concomitant internalization and degradation of the initially bound EGF. When the EGF receptor on cultured 3T3 cells is affinity labeled with high specific activity 125I-EGF, and the fate of the affinity labeled EGF-recepto... |
459511 | Analysis of transmembrane dynamics of cholera toxin using photoreactive probes. | Using sodium dodecyl sulfate--polyacrylamide gel electrophoresis and autoradiography, we have shown that 125I-labeled cholera toxin binds to Newcastle disease virus. Pretreatment of Newcastle disease virus with "cold" cholera toxin (at 37 degrees C for 30 minutes) inhibits the binding of 125I-labeled toxin in a subsequ... |
222967 | Predictive value of the analogy between hormone-sensitive adenylate cyclase and light-sensitive photoreceptor cyclic GMP phosphodiesterase: a specific role for a light-sensitive GTPase as a component in the activation sequence. | We report experiments which involve a light sensitive GTPase in the light dependent activation of retinal rod 3'5'-cyclic guanosine monophosphate (cGMP) phosphodiesterase (PDE). The data suggest that the light activated GTPase is intermediate between rhodopsin and PDE in the light-dependent activation sequence. We list... |
222966 | Effect of metabolic inhibitors on vasopressin-stimulated transport systems in the toad bladder. | Vasopressin increases the permeability of receptor cells to water and, in tissues such as toad bladder, to solutes such as urea. While cyclic AMP appears to play a major role in mediating the effects of vasopressin, there is evidence that activation of the water permeability system and the urea permeability system invo... |
582325 | Independence of the lethal actions of glucocorticoids on lymphoid cells from possible hormone effects on calcium uptake. | We have examined the possibility that hormone-induced increases in calcium uptake might initiate the lethal actions of glucocorticoids in two types of lymphoid cells. Hormone-induced increases in nuclear fragility are used as the measure of hormone action, since in both rat thymus cells and in mouse P1798 lymphosarcoma... |
222965 | Cholera toxin-catalysed ADP-ribosylation of erythrocyte proteins: general properties. | Upon incubation of lysed pigeon erythrocytes with NAD, adenosine diphosphate-ribose (ADP-ribose) is incorporated into nuclear poly ADP-ribose and into an unidentified acid-insoluble product of the cytosol. The properties of these incorporations have been examined and a method developed for reducing their amount whilst ... |
88548 | Structure, function, and antigenicity of cholera toxin. | Chemical modification of intact cholera toxin or its B subunit by either partial nitration or reduction and alkylation did not result in significant loss of biological activity as determined by measurement of cyclic AMP in Chinese hamster ovary cells. Complete nitration or succinylation in the presence of guanidine hyd... |
222964 | Activation of cyclic AMP-dependent protein kinase and stimulation of protein phosphorylation in response to adenosine in C-1300 murine neuroblastoma. | DEAE-cellulose chromatography of the 20,000g supernatant fraction of homogenates of C-1300 murine neuroblastoma (clone N2a) yields one major and two minor peaks of cyclic AMP-dependent protein kinase activity. Assessment of the endogenous activation state of the enzyme(s) reveals that the enzyme is fully activated by t... |
222963 | Growth factors and gangliosides: a possible new perspective in neuronal growth control. | For many permanent cell lines the transition from a growing (P) to a resting (R) state is reversibly controlled by growth factors present in serum. This P-to-R transition was studied in a neuronal cell line (B104) with respect to the action of serum, dibutyryl cyclic AMP (DBcAMP), gangliosides, and a glioma cell-produc... |
439896 | Cross-linkings between spectrin and band 3 in human erythroycte membranes. | A specific structural association between spectrin component 1 and band 3 in human erythrocyte membrane has been demonstrated by covalent cross-linkings, specific labeling, and the technique of two-dimensional gel electrophoresis. A complex of 330,000 daltons, representing 1 + 3, was produced in mildly oxidized membran... |
439895 | Differences in the redistribution of concanavalin A and wheat germ agglutinin binding sites on mouse neuroblastoma cells. | Concanavalin A (Con A), wheat germ agglutinin (WGA), and Ricinus communis agglutinin (RCA) bound with either 125I, fluorescent dyes, or fluorescent polymeric microspheres were used to quantitate and visualize the distribution of lectin binding sites on mouse neuroblastoma cells. As viewed by fluorescent light and scann... |
220466 | Requirement for guanosine triphosphate in the activation of adenylate cyclase by cholera toxin. | The activation of adenylate cyclase in lysed pigeon erythrocytes requires, among several cofactors, a nucleotide which may be ATP, GTP, or many other triphosphates. However, after removal of endogenous nucleotides by gel filtration or by adsorption onto charcoal the requirement can be met only by GTP, or an analog of G... |
571499 | A possible modulation of acetylcholine receptors of embryonic chick muscle cells by alpha-bungarotoxin. | Acetylcholine receptors were assayed with alpha-bugarotoxin on embryonic chick skeletal muscle growing in primary cell culture. Toxin was bound specifically to muscle cells and could be competed with D-tubocurarine. Two dissociation constants were obtained by equilibrium binding: 7.2 x 10(-9)M and 2.7 x 10(-7)M at 25 d... |
439893 | Tight junction development between cultured hepatoma cells: possible stages in assembly and enhancement with dexamethasone. | Freeze-fracture and thin-section methods were used to study tight junction formation between confluent H4-II-E hepatoma cells that were plated in monolayer culture in media with and without dexamethasone, a synthetic glucocorticoid. Three presumptive stages in the genesis of tight junctions were suggested by these stud... |
439892 | Proteolytic cleavage and structural transformation: their relationship in bacteriophage T4 capsid maturation. | Giant T4 phage capsoids formed in canavanine-treated cultures infected by phage mutants in genes 21 and 17, respectively, differ with regard to cleavage of the major capsid protein, gp23, and in the fine structure of their hexagonal surface lattices. Quantitative computer processing of electron micrographs shows that t... |
312157 | Reconsideration of influenza A virus nomenclature: a WHO memorandum. | The system of nomenclature for influenza A viruses recommended by WHO in 1971 provided a basis for the designation of these viruses into types based on their nucleoprotein antigens. Influenza A viruses were further divided into subtypes based on the antigenic character of their haemagglutinin and neuraminidase componen... |
373751 | Polarization of chlorotetracycline fluorescence in pancreatic islet cells and its response to calcium ions and D-glucose. | Suspensions rich in pancreatic beta-cells were prepared from non-inbred ob/ob-mice, incubated with 10 micrometer-chlorotetracycline, and analysed for fluorescence polarization in a microscope. Throughout the temperature range 16--38 degrees C, fluorescence was enhanced by 5 mM-Ca2+ in the incubation medium; 20 mM-D-glu... |
430595 | Physical characterization of the superhelical DNA genome of an enveloped mycoplasmavirus. | Mycoplasmavirus MVL2 is a nonlytic enveloped virion containing DNA. This DNA has been shown to be a double-stranded circular superhelical molecule of 11.8 kilobase pairs (7.8 X 10(6) daltons). The superhelix density is greater than that of phi X174 RFI but less than that of PM2 phage DNA. A physical map of the MVL2 gen... |
284377 | Competitive inhibition of colchicine binding to tubulin by microtubule-associated proteins. | Microtubule-associated proteins (MAPs) promote tubulin polymerization, whereas colchicine inhibits this process. In this paper, MAPs have been shown to inhibit colchicine binding to tubulin in a competitive manner. Attempts were made to identify which of the MAPs fraction(s) was responsible; both tau protein (a thermos... |
284344 | Self-assembly of microtubules in extracts of cultured HeLa cells and the identification of HeLa microtubule-associated proteins. | Microtubule protein from HeLa cell extracts was purified by multiple cycles of polymerization and depolymerization in the absence of glycerol or other exogenous polymerization-stimulatory agents. Approximately 4-5% of the extract protein was tubulin, of which more than one-half was competent to participate in polymeriz... |
284334 | Biosynthesis and self-assembly of protein S, a development-specific protein of Myxococcus xanthus. | Myxococcus xanthus is a Gram-negative bacterium that has a complex life cycle including a temporal sequence of cellular aggregation, mound formation, and myxosporulation. During development, protein S (molecuar weight 23,000) is induced and accumulates in very large amounts. Protein S was found in the soluble fraction ... |
570568 | Copurification of actin and desmin from chicken smooth muscle and their copolymerization in vitro to intermediate filaments. | Desmin is a 50,000-mol wt protein that is enriched along with 100-A filaments in chicken gizzard that has been extracted with 1 M KI. Although 1 M KI removes most of the actin from gizzard, a small fraction of this protein remains persistently insoluble, along with desmin. The solubility properties of this actin are th... |
419928 | Granule-containing cells in the human superior cervical ganglion. | The fine structure of granule-containing cells in the human superior cervical ganglion is described. These cells are larger than the typical SIF cells in mammals and exhibit green-yellow fluorescence. They are characterized by numerous granular vesicles (80-140 nm in diameter) in the cytoplasm, but have many features i... |
367575 | A randomized study of two different schedules of methyl CCNU, 5-FU and vincristine for metastatic colorectal carcinoma. | Sixty-seven patients with measurable colorectal carcinoma were randomized to receive two different schedules of Methyl CCNU, 5-FU and Vincristine (MOF). The treatment schedule consisted of Methyl CCNU 150 mg/m2 po q 70 days, 5-FU 300 mg/m2 iv for 5 consecutive days q 35 days, and Vincristine 1 mg/m2 IV q 35 days. The s... |
6169338 | The antibody response to myoglobin is independent of the immunized species. Analysis in terms of replacements in the antigenic sites and in environmental residues of the cross-reactions of fifteen myoglobins with sperm-whale myoglobin antisera raised in different species. | The recent determination of the entire antigenic structure of sperm-whale myoglobin with rabbit and goat antisera has permitted the examination of whether the antigenic structure recognized by antibodies depends on the species in which the antisera are raised. Also, by knowledge of the antigenic structure, the molecula... |
6266539 | Orientation of spin-labeled myosin heads in glycerinated muscle fibers. | We have used electron paramagnetic resonance (EPR) spectra to study spin labels selectively and rigidly attached to myosin heads in glycerinated rabbit psoas muscle fibers. Because the angle between the magnetic field and the principal axis of the probe determines the position of the EPR absorption line, spectra from l... |
6266538 | Submillisecond rotational dynamics of spin-labeled myosin heads in myofibrils. | The rotational motion of crossbridges, formed when myosin heads bind to actin, is an essential element of most molecular models of muscle contraction. To obtain direct information about this molecular motion, we have performed saturation transfer EPR experiments in which spin labels were selectively and rigidly attache... |
6263181 | Anti-herpes simplex virus and anti-human cell growth activity of E-5-propenyl-2'-deoxyuridine and the concept of selective protection in antivirus chemotherapy. | E-5-Propenyl-2'-deoxyuridine (E-5-propenyl-dUrd) inhibited the growth of herpes simplex virus (HSV) types 1 (HSV-1) and 2 in culture. The concentration of drug required to give a 2-log reduction in virus titer was 5 microM for HSV-1 and 23 microM for HSV-2. The anti-HSV-1 activity of this agent was more potent than 5-p... |
6452632 | Regulation of myosin self-assembly: phosphorylation of Dictyostelium heavy chain inhibits formation of thick filaments. | Dictyostelium myosin is composed of two heavy chains and two pairs of light chains in a 1:1:1 stoichiometry. Myosin purified from amoebae grown in medium containing [32P]phosphate had two of the subunits labeled (0.2-0.3 mol of phosphate per mol of 210,000-dalton heavy chains and approximately 0.1 mol of phosphate per ... |
7217291 | A microliter method for the gas chromatographic determination of long-chain non-esterified fatty acids in human serum or plasma. | Non-esterified fatty acids (NEFA) from C12 to C24 are assayed in human serum or plasma in a four-step procedure: extraction, volume reduction, methylation and gas chromatography. NEFA are extracted with chloroform--heptane--methanol from 50--100 microliter of serum or plasma buffered with phosphate. After adding ethyl ... |
7207469 | Changes in energy charge and block of protein synthesis in rabbit reticulocytes under the action of valinomycin. | Valinomycin blocks protein synthesis at the elongation stage in intact reticulocyte while being without action on a cell free system. We demonstrate here that this membrane mediated inhibition is accompanied by a change of the energy charge (ATP/ADP/AMP ratio) of the cells. There seems to be an accumulation of AMP with... |
6780572 | Widespread distribution of a 210,000 mol wt microtubule-associated protein in cells and tissues of primates. | Antisera prepared against a 210,000 mol wt microtubule-associated protein (210k MAP) isolated from the human cell line, HeLa, were used to survey a variety of cells and tissues for the presence of immunologically related proteins. The antisera were employed to test extracts of the cells and tissues, using a sensitive i... |
7007396 | Immunofluorescence localization of HeLa cell microtubule-associated proteins on microtubules in vitro and in vivo. | Rabbit antisera were prepared against the two major groups of microtubule-associated proteins (MAPs) from HeLa cells, proteins of approximately 210,000 molecular weight (210k MAPs), and 125,000 mol wt (125k MAPs). These antisera were characterized by a sensitive antigen detection technique that employs immunofluorescen... |
6893987 | Microfilaments and tropomyosin of cultured mammalian cells: isolation and characterization. | Microfilaments were isolated from cultured mammalian cells, utilizing procedures similar to those for isolation of "native" thin filaments from muscle. Isolated microfilaments from rat embryo, baby hamster kidney (BHK- 21), and Swiss mouse 3T3 cells appeared structurally similar to muscle thin filaments, exhibiting lon... |
7006663 | Report on the second myelomatosis trial after five years of follow-up. Medical Research Council's Working Party on Leukaemia in Adults. | Three hundred and seventy-two patients were randomized between 3 regimens of chemotherapy: cyclophosphamide, intermittent melphalan, and melphalan with prednisone, and were followed up to death or for at least 5 years. There was no difference in survival between the treatments, either overall or in any subgroup of pati... |
6161202 | Human autoantibodies that react with both cell nuclei and plasma membranes display specificity for the octamer of histones H2A, H2B, H3, and H4 in high salt. | Sera of some patients with systemic lupus erythematosus and related diseases contain a polyclonal antibody population (cross-reactive antinuclear antibodies [X-ANA]) that react specifically with both core mononucleosomes and plasma membranes of viable nucleated cells. Native mononucleosomes and nucleosome cores assembl... |
6450259 | Release of endogenous C3b inactivator from lymphocytes in response to triggering membrane receptors for beta 1H globulin. | Human bone marrow-derived lymphocytes and cells from B lymphoblastoid lines were shown to have specific membrane receptors for beta 1H globin. Lymphocytes responded to the presence of beta 1H by releasing endogenously-synthesized C3b-inactivator. Very little spontaneous release of C3b-inactivator occurred in the absenc... |
6160140 | Patterns of protein production in Myxococcus xanthus during spore formation induced by glycerol, dimethyl sulfoxide, and phenethyl alcohol. | Spore formation of Myxococcus xanthus can occur not only on agar plates during fruiting body formation, but also in a liquid culture by simply adding glycerol, dimethyl sulfoxide, or phenethyl alcohol to the culture. This chemically-induced spore formation occurs synchronously and much faster than that occurring during... |
7236213 | Purification of glutamate dehydrogenase from ox brain and liver. Evidence that commercially available preparations of the enzyme from ox liver have suffered proteolytic cleavage. | 1. A rapid procedure, involving ion-exchange chromatography on DEAE-cellulose and affinity chromatography on GTP-Sepharose, was used to purify glutamate dehydrogenase from ox brain and liver. 2. Preparations purified in this way differed from those of the ox liver enzyme that were obtained from commercial suppliers in ... |
6894314 | Morphological characterization of liposome suspensions by stereological analysis of freeze-fracture replicas from spray-frozen samples. | A method for size distribution analysis of liposome suspensions is described. Spray-freezing was used in order to avoid cryoprotectants and fixatives. Light scattering showed that, depending on their composition, liposomes can be modified by the spraying procedure. dipalmitoylphosphatidylcholine liposome suspensions di... |
7443534 | Mechanism of RNA-protein interactions in tobacco mosaic virus: analysis of the pH stability of virus protein complexes with synthetic polynucleotides. | TMV-like RNP complexes were reconstituted from TMV protein and synthetic polynucleotides. Analysis of the pH stability of RNP with polynucleotides containing U, G, or their analogues reveals a correlation between the stability of their structure and the pK values of the bases, and indicates that the -NH-CO-groups of U ... |
6160107 | Interaction of Mycoplasma gallisepticum with sialyl glycoproteins. | The binding of several glycoproteins to freshly grown and harvested cells of Mycoplasma gallisepticum was examined. Only human glycophorin, the major sialoglycoprotein of the erythrocyte membrane, bound tightly as judged by direct binding assays with 125I-labeled glycoproteins. Neuraminidase-treated glycophorin did not... |
7434003 | Calcofluor white ST Alters the in vivo assembly of cellulose microfibrils. | The fluorescent brightener, Calcofluor White ST, prevents the in vivo assembly of crystalline cellulose microfibrils and ribbons by Acetobacter xylinum. In the presence of more than 0.01 percent Calcofluor, Acetobacter continues to synthesize high-molecular-weight beta-1,4 glucans. X-ray crystallography shows that the ... |
6159496 | Water-soluble, dextran-linked retinal: preparation, vitamin A-like activity in rats, and effects on melanoma cells. | A new, water-soluble, polymer-linked form of retinal was synthesized and tested for its ability to support the growth of vitamin A-deficient noninbred Holtzman rats and to inhibit the proliferation of melanoma cells in culture. Retinal was conjugated to the hydrazide of carboxymethyldextran in the presence of alpha-and... |
6448863 | Structural basis of motility in the microtubular axostyle: implications for cytoplasmic microtubule structure and function. | The gross morphology of the protozoan microtubule axostyle of Saccinobaculus ambloaxostylus can now be described in macromolecular detail. The left-handed coil of the axostyle is seen to be dependent upon the asymmetry inherent in the constituent microtubules as expressed by the specific array of linkages between micro... |
6776096 | Differences in the architecture of cytoplasmic and intracytoplasmic membranes of three chemotrophically and phototrophically grown species of the Rhodospirillaceae. | Freeze-fracture faces of membranes of either chemotrophically or phototrophically grown Rhodospirillum rubrum, Rhodopseudomonas sphaeroides, and Rhodospirillum tenue were analyzed. All three species differed from each other with respect to size as well as numerical density (number per square micrometer) of intramembran... |
6253080 | E. coli and M. luteus DNA topoisomerase I can catalyze catenation of decatenation of double-stranded DNA rings. | Escherichia coli and Micrococcus luteus DNA topoisomerase I are found to promote catenation of double-stranded DNA rings. At low DNA concentration dimeric catenanes are the major catenated products; at high DNA concentration or when spermidine is present, catenanes containing more than two rings are formed. There is no... |
7191514 | Lumbosacral spinal evoked potentials in humans. | Evoked potentials in response to submaximal electrical stimuli to the peroneal or tibial nerves were recorded from the lumbosacral region in 18 normal subjects. Averaging of 128 responses from recording electrodes over spinous processes S1 to T11, with a reference electrode on the contralateral iliac crest, demonstrate... |
7018608 | Nuclear magnetic resonance of the filamentous bacteriophage fd. | The filamentous bacteriophage fd and its major coat protein are being studied by nuclear magnetic resonance (NMR) spectroscopy. 31P NMR shows that the chemical shielding tensor of the DNA phosphates of fd in solution is only slightly reduced in magnitude by motional averaging, indicating that DNA-protein interactions s... |
7018607 | Regulation of coat protein polymerization by the scaffolding protein of bacteriophage P22. | In the morphogenesis of double stranded DNA phages, a precursor protein shell empty of DNA is first assembled and then filled with DNA. The assembly of the correctly dimensioned precursor shell (procapsid) of Salmonella bacteriophage P22 requires the interaction of some 420 coat protein subunits with approximately 200 ... |
7248453 | Patterns in the quinary structures of proteins. Plasticity and inequivalence of individual molecules in helical arrays of sickle cell hemoglobin and tubulin. | The four recognized levels of organization of protein structure (primary through quaternary) are extended to add the designation quinary structure for the interactions within helical arrays, such as found for sickle cell hemoglobin fibers or tubulin units in microtubules. For sickle cell hemoglobin the main quinary str... |
7248452 | Energetics of subunit assembly and ligand binding in human hemoglobin. | An extensive and self-consistent set of thermodynamic properties has recently been established for the coupled processes of subunit assembly and ligand binding (oxygen and protons) in human hemoglobin. The resulting thermodynamic values permit a consideration of the possible sources of energetic terms accounting for st... |
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