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194223 | Specificity of DNA basic polypeptide interactions. II+ Influence of aromatic amino acid residues investigated with agarose bound lysine copolypeptides. | Binding affinities towards DNA and base pair specificities of lysine copolymers, containing different amounts of Phe, Tyr or Trp residues, were estimated using a previously described chromatographic method. Incorporation of few aromatic residues into polylysine causes a decrease in the binding affinity, however, furthe... |
139610 | Reconstitution of thermostable ATPase capable of energy coupling from its purified subunits. | Purified dicyclohexylcarbodiimide-sensitive ATPase (TF0-F1) from thermophilic bacterium PS3 is composed of a water soluble part with ATP hydrolytic activity (TF1) and a water insoluble moiety (TF0). All of the five subunits (alpha, beta, gamma, delta, and epsilon) of TF1 were isolated. TF1 was reconstituted from the fi... |
265545 | Human somatotropin: restoration of full biological activity by noncovalent interaction of a natural and a synthetic fragment of the hormone. | The recombinant hormone obtained by noncovalent interaction of the natural NH2-terminal fragment (consisting of 134 amino acid residues) with a synthetic COOH-terminal fragment of 52 amino acids of the reduced-carbamidomethylated human somatotropin molecule is found to exhibit full biological activity of the native hor... |
15136 | Receptor interaction between eastern equine encephalitis virus and chicken embryo fibroblasts. | The attachment of eastern equine encephalitis virus to chicken embryo fibroblasts was studied at 0 degrees C. The binding specifically responsible for initiating infection was studied in the initial experiments by employing plaque-forming ability as the measured response. Results from these initial studies were closely... |
845115 | Formation and function of Vibrio parahaemolyticus lateral flagella. | Formation of the lateral flagella (L-flagella) of Vibrio parahaemolyticus was studied immunologically, using specific antiserum against L-flagella. On solid medium, L-flagella were formed at both high (37 degrees C) and low (25 degrees C) temperatures, although at high temperatures they became dissociated from the cell... |
843521 | A 13C nuclear magnetic resonance study of gel-forming (1 goes to 3)-beta-d-glucans. Evidence of the presence of single-helical conformation in a resilient gel of a curdlan-type polysaccharide 13140 from Alcaligenes faecalis var. myxogenes IFO 13140. | A 13C nuclear magnetic resonance (NMR) study of a resilient gel of a curdlan-type polysaccharide 13140, a (1 goes to 3)-beta-D-glucan, from Alcaligenes faecalis var. myxogenes IFO 13140, was performed in an effort to understand the gel structure. It was found that very broad 13C resonance peaks of line widths ca. 150 (... |
65355 | Arrangement of high molecular weight associated proteins on purified mammalian brain microtubules. | The arrangement of the high molecular weight proteins associated with the walls of reconstituted mammalian brain microtubules has been investigated by electron microscopy of negatively stained preparations. The images are found to be consistent with an arrangement whereby the high molecular weight molecules are spaced ... |
870592 | Temporary contacts formed between developing optic fibers in the chick. | Temporary junctions were observed between developing optic fibers of the chick embryo and were distributed along the entire length of the axons from the cell body to the tip of the growth cone. These junctions were present in all material studied between days E-3 and E-18, the latter being the start of myelin formation... |
849271 | Mechanism of "L"-type pyruvate kinase from rabbit liver. Evidence against phosphoenzyme formation. | The "L"-type pyruvate kinase from rabbit liver does not catalyse exchange between phosphoenol[1-14C]pyruvate and pyruvate at either pH 8.5 or 6.2. Spectrophotometric experiments at pH 8.5 and 6;2 and gel-filtration experiments with [32P]phosphoenolpyruvate at pH 8,5 also fail to demonstrate phosphoenzyme formation. It ... |
576803 | [Ultrastructural morphometric analysis of the spiral ganglion in guinea pigs (author's transl)]. | This is the first morphometric analysis of the cochlear spiral ganglion. Therefore the ganglion was subdivided in precisely defined compartments. We found that the normal, untreated spiral ganglion in guinea pigs contains 58% ganglion cells of the granular type, 26% satellite cells and Schwann cells, 8.6% extracellular... |
139608 | Roles of proteins from inner face of plasma membranes in susceptibility of of (Na+ + K+)-stimulated Mg2+ adenosinetriphosphatase to ouabain. | Purified right-side-out (RSO) and inside-out (IO) plasma membrane vesicles release 35% of the total plasma membrane proteins after EDTA treatment. After such a treatment both types of vesicles exhibited the same total activity of (Na+ + K+)-stimulated Mg2+ adenosinetriphosphatase (ATPase; ATP phosphohydrolase, EC 3.6.1... |
265520 | Assembly of tobacco mosaic virus in vitro: elongation of partially reconstituted RNA. | It was reported that the rate of elongation of partially reconstituted RNA, if prepared without centrifugation, showed dependency upon the state of protein aggregation like that found when free RNA was used as the nucleic acid source [Butler, P. J. G. (1974) J. Mol. Biol. 82, 333-341]. Butler concluded from this result... |
322127 | Conditionally lethal ribosomal protein mutants: characterization of a locus required for modification of 50S subunit proteins. | Mutagenized P1 bacteriophage were used to transduce a marker (aroE) adjacent to the cluster or ribosomal protein genes located at 72 min on the Escherichia coli chromosome. Linked temperature-sensitive transductants were isolated and characterized. A mutant unable to grow at 44 degrees was found to be defective in prot... |
844544 | On the location of the tetrapyrrole macrocycle of chlorophyll a in phospholipid vesicles and in hexadecane. | The state of chlorophyll a in phosphatidylcholine vesicles was examined. The results indicate that the chlorophylls are present in monomeric form. A kinetic study of chlorophyll reactions with K2S2O8 and piperidine showed that these substances react with the porphyrin rings of pigments located on both vesicle faces, mo... |
189812 | Outer membrane of Salmonella typhimurium. Electron spin resonance studies. | The supramolecular structure of the outer membrane of Salmonella typhimurium that produces an Rc-type lipopolysaccharide was studied by adding spin-labeled fatty acid probes to membranes as well as model bilayers. Lipopolysaccharide of this organism apparently formed a bilayer structure in 0.2 M NaCl/0.01 M MgCl2, and ... |
319253 | Gene D of bacteriophage phi X 174: absence of transcriptional and translational regulatory properties. | The only evidence that a gene product of phi chi 174 is involved in the regulation of phage transcription was presented by Clements and Sinsheimer (1974) for gene D. I. found, in attempting to investigate this possibility further, that the D protein had no regulatory effect. When the D protein was eliminated by various... |
299859 | Emergence of insulin receptors upon alloimmune T cells in the rat. | Insulin, as well as other ligands which increase intracellular guanosine 3',5'-cyclic monophosphate (cGMP), augments thymic-derived (T)- lymphocyte effector activity as revealed by alloimmune lymphocyte-mediated cytotoxicity. The observation that insulin binds only to monocytes among circulating nonimmune human mononuc... |
565254 | The sub-structure of nucleosomes. | A model for the sub-structure of the core particle of the nucleosome in chromatin, based on results from neutron and x-ray scattering and other physico-chemical observations, is presented. Two disc-shaped heterotypic tetramers of histones, opposed face-to-face, form the core protein. Each tetramer is enclasped by an an... |
604697 | Distribution of glycoconjugates in mouse fibroblasts with varying degrees of tumorigenicity. | Analysis of glucosamine labeled glycoconjugates in cultured cells has been made comparing 2 clones and the parent embryonic mouse cell line. Hyaluronic acid, heparan sulphate, and chondrotin sulphate as well as a complex mixture of glycopeptides were found in the medium, the trypsinate, and the trypsinized cells, altho... |
24139 | Localization of some glycolipid glycosylating enzymes in the Golgi apparatus of rat kidney. | Cell fractions from rat kidney were isolated and studied for their ability to synthesize several possible intermediates in the biosynthesis of sulfatides and gangliosides. The enzymes studied include UDP-Gal:ceramide galactosyltransferase, UDP-Gal:glucosylceramide galactosyltransferase, UDP-Gal:galactosylceramide galac... |
415185 | The inhibitory effect of the artificial electron donor system, phenazine methosulfate-ascorbate, on bacterial transport mechanisms. | The artificial electron donor system, phenazine methosulfate (PMS)-ascorbate, inhibited active transort of solutes in Pseudomonas aeruginosa irrespective of whether the active transport systems were shock sensitive or shock resistant. N,N,N',N'-tetramethylphenylenediamine could be substituted for PMS but a higher conce... |
564429 | Involvement of membrane sulfhydryls in the activation and maintenance of nutrient transport in chick embryo fibroblasts. | At 5 microgram/ml, insulin stimulates hexose, A-system amino acid, and nucleoside transport by serum-starved chick embryo fibroblasts (CEF). This stimulation, although variable, is comparable to that induced by 4% serum. The sulfhydryl oxidants diamide (1-20 micrometer). hydrogen peroxide (500 micrometer), and methylen... |
415184 | On the rate limiting step in downhill transport via the LacY permease of Escherichia coli. | Strains of Escherichia coli K12 were constructed for the specific purpose of evaluating the inducibility of the influx mechanism controlled by the lacY gene. These strains are heteromerodiploids characterized by a high and relatively constant level of beta-D-galactosidase which is not affected significantly by inductio... |
604696 | Structural analysis of a membrane glycoprotein: glycophorin A. | Glycophorin A is the major sialoglycoprotein of the human erythrocyte membrane. Structural studies indicate that this molecule is made up of 3 domains composed of 2 hydrophilic segments which are separated by a region of 22 nonpolar amino acids. The N-terminal half of the molecule contains all the carbohydrate associat... |
604695 | Kinetics of Na+-dependent D-glucose transport. | The kinetic parameters of the Na+-dependent glucose transport system have been determined in isolated membrane vesicles for D-glucose, Na+, and phlorhizin. The D-glucose flux measurements were carried out by the equilibrium exchange procedure at constant external and internal Na+ concentrations and zero potential. Equa... |
601108 | Measurements of water proton NMR spin-lattice relaxation time in the rotating frame (T1p) for studying motions in solutions of giant macro-molecules and supramolecular particles (T2 virus). | Spin-spin relaxation time (T2), spin-lattice relaxation time (T1), and spin-lattice relaxation time in the rotating frame (T1p) of water protons in solutions of bacteriophage T2 were studied by pulsed nuclear magnetic resonance. The frequency dependence of the measurements exhibits a dispersion implying existence of a ... |
599936 | Biochemical characteristics, metabolism, and antitumor activity of several acetylated hexosamines. | We have synthesized several potential inhibitors and/or modifiers of the carbohydrate portion of plasma membrane glycoconjugates. These include fluorinated and actylated analogs of D-glucosamine, D-galactosamine, and D-mannosamine. These compounds have been tested to determine their effects on both[14C] glucosamine and... |
563956 | Cell surface carbohydrates of preimplantation embryos as assessed by lectin binding. | Preimplantation embryos were obtained from the uteri and oviducts of 2 strains of mice, Swiss CD-1 and B6CBA. After removal of the zona pellucida by treatment with pronase, FITC-lectins were bound to the embryonic cell surfaces at either 4 degrees C or 37 degrees C. Both morula and blastocyst stage embryos bound the fo... |
202808 | Glycosylation of VSV glycoprotein is similar in cystic fibrosis, heterozygous carrier, and normal human fibroblasts. | The single envelope glycoprotein of vesicular stomatitis virus was used as a specific probe of glycosyltransferase activities in fibroblasts from two cystic fibrosis patients, an obligate heterozygous carrier and a normal individual. Gel filtration of pronase-digested glycopeptides from both purified virions and infect... |
599935 | Effect of calcium on the pellet height response of Tetrahymena cilia. | The pellet height response (a measure of the increase in height of the pellet of cilia obtained by brief centrifugation in the presence of ATP as compared to the absence of ATP) of Tetrahymena cilia prepared by deciliation in the presence of Ca2+ is sensitive to the concentration of free Ca2+ during the pellet height a... |
340794 | Prediction for secondary structures of ten proteins from the 50S subunit of the Escherichia coli ribosome. | Predictions of the secondary structures of the following 10 proteins from the large subunit of the E. coli ribosome were made using their known amino acid sequences: L6, L16, L19, L27, L28, L30, L31, L32, L33, and L34. The predictions were made according to 4 different methods and the results for each protein are prese... |
599934 | Studies related to the head-maturation pathway of bacteriophages T4 And T2:II. nuclear disruption, protein synthesis and particle formation with the mutant 43-.30-.46-. | We describe the aberrant phage multiplication of the triple conditional lethal mutant 43-(polymerase).30-(ligase).46-(exonuclease) of bacteriophage T4D in which phage DNA replication is arrested but some late protein synthesis occurs (33). The nuclear disruption is indistinguishable from wild type. Forty-five empty sma... |
599933 | Studies related to the head-maturation pathway of bacteriophages T4 and T2:I. morphology and kinetics of intracellular particles produced by mutants in the maturation genes. | Mutants in the genes governing the maturation of the head of bacteriophage T4 and in gene 24 were studied by electron microscopy of thin sections. We define morphologically: black particles, comprising mature, stable heads and immature, fragile heads, which break down upon lysis; grizzled particles, which apparently ar... |
598700 | [Comparative analysis of the spectrum of radiation-induced structural mutations in diploid and tetraploid cells of mouse bone marrow]. | A comparative analysis of the spectrum of radiation-induced mutations was carried out in diploid mouse bone marrow cells and in tetraploid cells obtained from the latter by means of colchicine treatment. It is established that solitary chromatid deletions prevail among aberrations induced at the G2--S stage. This is th... |
73630 | Cell antigens recognized by rabbit antibodies specific for oligomannosyl determinants. | Rabbit antibodies to cell wall mannans of various microbial strains and their mutants were found to be cross-reactive to cell carbohydrates of mammalian sperm and 4-6-days-old blastocysts. Immunochemical studies indicate that oligomers of alpha1 yields to 2, alpha1 yields to 3, alpha1 yields to 6, and probably also alp... |
563497 | Characterization of the Fc receptors of the murine leukemia L1210. | A glycoprotein extract prepared from the plasma membranes of L1210 cells was passed over columns of Sepharose 4B to which either heat-aggregated human IgG or F(ab')2 fragments has been coupled. The intact IgG column bound 35.7 percent of the applied counts, whereas the F(ab')2 columns bound 2.8 percent. The bound glyco... |
592824 | Sialic acid uptake by BHK cells and subsequent incorporation into glycoproteins and glycolipids. | BHK cells can be grown in the presence of growth medium to which radiolabeled sialic acid has been added. After 24 h, 85 percent of the radioactivity in the cells is covalently bound to glycoproteins and glycolipids. No metabolism of the radiolabeled sialic acid could be detected. |
592823 | The amino- and carboxyl-terminal sequence of bovine rhodopsin. | The amino terminus of bovine rhodopsin is blocked and has the sequence x-Met-Asn(CHO)-Gly-Thr-Glu-Gly-Pro-Asn-Phe-Tyr-Val-Pro-Phe-Ser-Asn(CHO)-Lys-Thr-Gly-Val-Val-Arg, where CHO represents sites of carbohydrate attachment. The carboxyl-terminal sequence of rhodopsin is Val-Ser-Lys-Thr-Glu-Thr-Ser-Gln-Val-Ala-Pro-Ala. U... |
563496 | Distribution of a major surface-associated glycoprotein, fibronectin, in cultures of adherent cells. | Fibronectin was present in media and cell layers of cultures of adherent cells from human skin, kidney, lung, chest wall, liver, and heart. Cell-surface fibronectin, visualized by immunofluorescence, was in dense fibrillar (cultures from lung), discrete fibrillar (e.g., cultures from skin), or punctate (some cultures f... |
592822 | Carbon-13 as a tool for the study of carbohydrate structures, conformations and interactions. | The application of 13C-NMR spectroscopy to problems involving the structures and interactions of carbohydrates is described. Both 13C-enriched and natural abundance compounds were used and some advantages of the use of the stable isotope are described. Carbon-carbon and carbon-proton coupling constants obtained from 1-... |
413010 | High-affinity phlorizin binding to brush border membranes from small intestine: identity with (a part of) the glucose transport system, dependence on Na +-gradient, partial purification. | In the presence of an NaSCN gradient phlorizin binds with a high affinity (Kd similar or equal to 4.7 micron) to vesicles derived from brush border membranes of intestinal cells of rabbits. The value for Kd corresponds closely to that of Ki determined from phlorizin inhibition of sugar transport. The apparent affinity ... |
338995 | The mechanism of sugar-dependent repression of synthesis of catabolic enzymes in Escherichia coli. | Previous studies have indicated that the Escherichia coli adenylate cyclase (AC) activity is controlled by an interaction with the phosphoenolpyruvate (PEP): sugar phosphotransferase system (PTS). A model for the regulation of AC involving the phosphorylation state of the PTS is described. Kinectic studies support the ... |
563495 | Hexose transport regulation in cultured hamster cells. | Hamster (nil) cells maintained overnight in culture medium containing cyclohemiximide and either glucose or fructose exhibit strikingly different rates of hexose transport and metabolism (i.e. uptake). Pretreatment of cultures with sulfhydryl reagents makes it possible to determine initial transport rates for a physiol... |
592821 | The sialoglycoprotein subunits of human placental brush border membranes characterized by two-two-dimensional electrophoresis. | A brush border membrane enriched fraction was isolated from human full-term placenta. This membrane fraction exhibited large membrane fragments with microvilli projecting from the basal membrane in electron micrographs and was enriched tenfold in alkaline phosphatase, a brush border enzyme marker. The sialoglycoprotein... |
592820 | Microbial carbohydrate specific antibodies distinguish between different stages of differentiating mouse cerebellum. | High titered anticarbohydrate antibodies were used to identify cell surface carbohydrates during different stages in histogenesis of mouse cerebellum in a micro tissue-culture system which mimics selected features of in vivo cerebellum development. Blockage of fiber formation within the first few days in vitro and inhi... |
338994 | Chemical and immunological studies of cell surfaces from normal and transformed cells. | Immunological and chemical studies of cell surfaces from normal and transformed BALB/c fibroblasts have shown alterations associated with transformation. The cells studied include normal lines which do not cause tumors when injected into BALB/c mice, viral transformants, and spontaneous transformants which cause tumors... |
304124 | Homogeneous antibodies directed against human cell surface antigens: I. The mouse spleen fragment culture response to T and B cell lines derived from the same individual. | The use of the mouse spleen fragment culture system is extended to the production of antibodies to human lymphoblastoid cell lines. These antibodies were tested for reactivity against the immunizing cell line, and against a second cell line which had been derived from the same human blood sample. Many of the antibodies... |
201808 | Relationship between thymidine transport and phosphorylation in Novikoff rat hepatoma cells as analyzed by a rapid sampling technique. | Incorporation of thymidine into Novikoff rat hepatoma cells was analyzed with a rapid sampling technique which allowed collection of 12 time points in 20 sec. Transport was a rapid, saturable, nonconcentrative process with a Km of about 85 micrometer. The intracellular thymidine pool was also rapidly labeled in cells w... |
338992 | L-Arabinose transport and the L-arabinose binding protein of Escherichia coli. | The active accumulation of L-arabinose by arabinose induced cultures of Escherichia coli is mediated by 2 independent transport mechanisms. One, specified by the gene locus araE, is membrane bound and possesses a relatively "low affinity". The other, specified in part by the genetic locus araF, contains as a functional... |
338991 | Methods for rapidly altering the permeability of mammalian cells. | Various agents alter mammalian cells so that they rapidly become nonspecifically permeable to substances that ordinarily do not penetrate intact cells. Thus, toluene renders liver cells permeable to nucleotides and macromolecules. Tween 80 and Tween 60 act on similar fashion, and the effect is reversible. Dextran sulfa... |
22779 | Energetics of galactose, proline, and glutamine transport in a cytochrome-deficient mutant of Salmonella typhimurium. | The effect of inhibitors and uncouplers on the osmotic shock-sensitive transport systems for glutamine and galactose (by the beta-methyl galactoside permease) was compared to their effect on the osmotic shock-resistant proline and galactose permease systems in cytochrome-deficient cells of Salmonella typhimurium SASY28... |
22778 | Effects of sodium ions on the electrical and pH gradients across the membrane of Streptococcus lactis cells. | Energized cells of Streptococcus lactis conserve and transduce energy at the plasma membrane in the form of an electrochemical gradient of hydrogen ions (deltap). An increase in energy-consuming processes, such as cation transport, would be expected to result in a change in the steady state deltap. We determined the el... |
145517 | Association of (Ca + Mg)-ATPase activity with ATP-dependent Ca uptake in vesicles prepared from human erythrocytes. | Ghost membranes prepared from human erythrocytes exhibit 2 distinct (Ca + Mg)-ATPase1 activities (Quist and Roufogalis, Arch Biochem Biophys 168:240, 1975). (Ca + Mg)-ATPase activity dependent on a water soluble protein fraction is selectively lost from ghost membranes during preparation of vesicles under low ionic str... |
145516 | Defective transport of thymidine by cultured cells resistant to 5-bromodeoxyuridine. | A line of HeLa cells resistant to 5-bromo-2'-deoxyuridine (BUdR) was established by continuous culture in growth medium containing BUdR; during the selection period, BUdR concentrations, initially 15 micrometer, were gradually increased to 100 micrometer. Cells of a clone (HeLa/B5) established from this line were also ... |
592819 | Control of amino acid transport in the mammary gland of the pregnant mouse. | The regulation of the uptake of the amino acid analog alpha-aminoisobutyric acid was studied in diced mammary glands from pregnant mice. Stimulation of uptake by insulin was not prevented by inhibitors of protein synthesis; protein synthesis inhibitors decreased uptake by 20%; this response occurred more promptly in in... |
145515 | Active calcium treatment transport via coupling between the enzymatic and the ionophoric sites of Ca2+ + Mg2+-ATPase. | The 20K dalton fragment of Ca2+ + Mg2+-ATPase obtained from th tryptically digested sarcoplasmic reticulum has been further purified using Bio-Gel P-100. This removed low-molecular-weight UV-absorbing and positive Lowry-reacting contaminants. The ionophoric activity of the 20K fragment in both oxidized cholesterol and ... |
145514 | Isolation of membrane vesicles with inverted topology by osmotic lysis of Azotobacter vinelandii spheroplasts. | Membrane vesicles were prepared from Azotobacter vinelandii spheroplasts by lysis in either potassium phosphate (pH 7.0) or Tris1-acetate (pH 7.8) buffers. These 2 types of preparations differ considerably in their properties: 1) Examination by scanning electron microscopy reveals that the Pi vesicles consist primarily... |
201807 | Hormonal regulation of membrane phenotype. | Incubation of rat hepatoma cells (HTC) in tissue culture with glucocorticoids alters several membrane properties characteristic of transformed cells, without affecting the growth rate of these cells. Variant cell lines resistant to dexamethasone inhibition of plasminogen activator production have been isolated using an... |
592818 | Thermodynamics, the structure of integral membrane proteins, and transport. | Membranes are structures whose lipid and protein components are at, or close to, equilibrium in the plane of the membrane, but are not at equilibrium across the membrane. The thermodynamic tendency of ionic and highly polar molecules to be in contact with water rather than with nonpolar media (hydrophilic interactions)... |
592817 | The sub-membrane reticulum of the human erythrocyte: a scanning electron microscope study. | A web-like reticulum underlying the human erythrocyte membrane was studied at a resolution of 5-10 nm by means of scanning electron microscope. The network was visualized in isolated membranes (ghosts) torn open to reveal their interior space and in residues derived from ghosts extracted with Triton X-100. It formed a ... |
592816 | Accessibility of the carbohydrate moiety of membrane-boound rhodopsin to enzymatic and chemical modification. | Galactose was specifically inserted into the carbohydrate moiety of rhodopsin by incubating retinal disk membranes with UDP-galactose: N-acetylglucosamine galactosyltransferase. The stoichiometry of labeling ranged from 1.2 to 1.8 (average = 1.5) residues of galactose per molecule of rhodopsin, indicating that some or ... |
409889 | Isolation and partial characterization of the heterophile antigen of infectious mononucleosis from bovine erythrocytes. | The heterophile antigen (Paul-Bunnell antigen, PBA) of infectious mononucleosis was isolated by extraction of an aqueous suspension of bovine erythrocyte stromata with chloroform-methanol (2:1). The upper aqueous layer contained gangliosides, PBA, and a high-molecular-weight glycoprotein. PBA and gangliosides were sepa... |
198614 | Perspectives and limitations of resolutions-reconstitution experiments. | Reconstitutions of membranous activities can tell us how many components are required and what their functions are. The mitochondrial proton pump is used as an example. Moreover, the biological activity, such as Pi transport, can be used in reconstituted vesicles as an assay during the isolation of the transporter. Rec... |
198613 | Hormonal regulation of hepatic amino acid transport. | The transport of 2-aminoisobutyric acid (AIB) into liver tissue was increased by both insulin and glucagon. We have now shown that these hormones do not stimulate the same transport system. Glucagon, possibly via cAMP, increased the hepatic uptake of AIB by a mechanism which resembled system A. This glucagon-sensitive ... |
909311 | Role of the membrane potential in serum-stimulated uptake of amino acid in a diploid human fibroblast. | The Na+-dependent accumulation of alpha-aminoisobutyric acid (AIB), measured in normal growing and quiescent (serum-deprived) HSWP cells (human diploid fibroblast), was found to be twofold higher (AIB/in/AIBout = 20-25) under the normal growing conditions. Serum stimulation of quiescent cells increases their AIB concen... |
896462 | Complex forms and replicative intermediates of mitochondrial DNA in tissues from adult and senescent mice. | The occurrence and types of complex forms and replicative intermediates of mitochondrial DNA (mtDNA) were investigated in tissues from C57BL/6J mice aged 10-11 months or 29-30 months. Total mtDNA from brain, heart, kidney and liver was isolated in ethidium bromide-CsCl gradients and examined by electron microscopy afte... |
197319 | Mutations affecting the binding, internalization, and lysosomal hydrolysis of low density lipoprotein in cultured human fibroblasts, lymphocytes, and aortic smooth muscle cells. | Studies comparing the metabolism of low density lipoprotein (LDL) in normal cells and in cells cultured from patients with homozygous familial hypercholesterolemia have disclosed the existence of a receptor for plasma LDL. This receptor has been identified on the surface of human fibroblasts, lymphocytes, and aortic sm... |
197318 | Isolation of the alanine carrier from the membranes of a thermophilic bacterium and its reconstitution into vesicles capable of transport. | A carrier protein mediating alanine transport was purified from the membranes of the thermophilic bacterium PS3, by ion exchange chromatography in the presence of both Triton X-100 and urea. The alanine carrier was recovered in the nonadsorbed fraction from either DEAE- or CM-cellulose columns, suggesting that its isoe... |
197315 | Cell shape and hexose transport in normal and virus-transformed cells in culture. | The rate of hexose transport was compared in normal and virus-transformed cells on a monolayer and in suspension. It was shown that: 1) Both trypsin-removed cells and those suspended for an additional day in methyl cellulose had decreased rates of transport and lower available water space when compared with cells on a ... |
558945 | [Study of intracranial dynamics by applying a water-soluble contrast medium, N-methylglucamine iothalamate, to the dog brain]. | The water-soluble contrast medium, N-methylglucamine iothalamate (NMGI), when injected in a dose of 1 ml into the cerebral parenchyma space of dogs (Feldberg's method), diffused within the lateral ventricle at a constant rate of flow against the nerve fibers running therein. Such was recorded by X-ray television and 16... |
863340 | Some remarks on oxidation of aryl- and alkylamines in fibers of the central nervous system. A histochemcial study. | Experiments were performed on brains of white Wistar rats, of both sexes, weighing 180-200g and 24 cats from various sources. Frontal sections were fixed in Backer's formalin and thereafter cut in a cryostat on 10 microns thick slices, dried on air. The slices were: a) either preincubated 1 hr in room temperature in so... |
851610 | [Physico-chemical properties of the DNP-systems of leukemia cells with different chromosome numbers]. | The binding between the components of the isolated DNP-complex proved to be more stable in leukemic cells in comparison with the normal lymphoid spleen cells. This conclusion was based on the investigation of the thermomechanical and disaggregation properties of the supramolecular DNP systems isolated from leukemic cel... |
14746 | Production of Schardinger beta-dextrin by soluble and immobilized cyclodextrin glycosyltransferase of an alkalophilic Bacillus sp. | Succinylated cyclodextrin glycosyltransferase (EC 3.2.1.19) of an alkalophilic Bacillus sp. was adsorbed on a vinylpyridine copolymer. The enzyme had about 25% of the activity of soluble enzyme added. No increase of pH or thermal stability of the enzyme was observed by the adsorption, whereas optimum temperature for th... |
190762 | Axonal and cellular alterations in the inner ear of rats treated with chlorphentermine or iprindole. | An electron-microscopic study was carried out on the inner ear of rats, which had been treated with the anorectic drug chlorphentermine and the antidepressant drug iprindole, two cationic amphiphilic compounds known to induce a generalized lipidosis. After chronic drug treatment the following vestibular and cochlear al... |
319771 | [Cyclodextrin glucanotransferase from Klebsiella pneumoniae. 1. Formation, purification and properties of the enzyme from Klebsiella pneumoniae M 5 al (author's transl)]. | 1. The strain M 5 al of Klebsiella pneumoniae grows excellently with starches. We were able to show that besides the pullulanase associated with the external membrane of the cells the bacterium produces an inducible, extracellular cyclodextrin glucanotransferase [1,4-alpha-D-glucan-4-alpha-(1,4-alpha-glucano)-transfera... |
264692 | Synthesis of two collagen types by embryonic chick corneal epithelium in vitro. | To better understand the mechanisms involved in matrix development, we have analyzed the collagen synthesized by embryonic corneal epithelium, the tissue known to produce the collagenous component of the primary corneal stroma. Isolated epithelia were cultured in vitro in medium containing [oH]proline and the newly syn... |
189304 | Synthesis and characterization of "face-to-face" porphyrins. | The syntheses of four binary porphyrins, two of which are constrained to a "face-to-face" conformation, and their Co2+ and Cu2+ derivatives are described. Electron spin resonance indicates that the intermetallic separation in the binuclear "face-to-face" porphyrins is about 6.5-6.8 A. Electronic spectra and proton magn... |
264669 | Inside-out model for self-assembly of tobacco mosaic virus. | Incompletely reconstituted particles of tobacco mosaic virus treated with moderate concentrations of dimethylsulfoxide prior to electron microscopy have two visible tails of unencapsidated RNA, a long one and a short one. The short tail has a constant length of 720 +/- 80 nucleotides in incomplete particles of diverse ... |
24425261 | Coumarin inhibition of microfibril formation at the surface of cultured protoplasts. | The effect of including coumarin in the culture medium of isolated tobacco leaf protoplasts has been studied by scanning microscopy. Fibre formation is completely suppressed for 48 h in concentrations of 200 and 250 mg/l of coumarin. Continuous culture in these concentrations of coumarin does not result in cell divisio... |
16592382 | Chlorophyll lasers: Stimulated light emission by chlorophylls and Mg-free chlorophyll derivatives. | Stimulated emission and lasing have been demonstrated for chlorophyll a, chlorophyll b, and bacteriochlorophyll a as well as for the Mg-free chlorophyll derivatives pheophytin a and methyl pheophorbide a. Population inversion was obtained by optically pumping with an N(2) laser. For the three chlorophylls, lasing was o... |
252453 | To stabilize a transition state. | Inspection of the active sites of the many enzymes whose structures are known at high resolution leads to the unsurprising conclusion that an enzyme may provide an environment that exquisitely stabilizes the transition state for an elementary catalytic step that is expected to be difficult. In an effort both to mimic s... |
616492 | The area-code hypothesis: the immune system provides clues to understanding the genetic and molecular basis of cell recognition during development. | Numberous studies of embryogenesis have provided evidence for highly specific cell-surface recognition phenomena. These include both the interactions of neighboring cells and the specific cellular migrations which occur as the developmental program of the embryo progresses. The area-code hypothesis elaborate here is an... |
211350 | Glycoprotein synthesis as a function of epithelial cell arrangement: biosynthesis and release of glycoproteins by human breast and prostate cells in organ culture. | We demonstrate that a technique is available to investigate glycoprotein synthesis in organ cultures of human breast and prostate surgical specimens where the 3-dimensional epithelial cell arrangement remains intact. Malignant breast and prostate epithelium maintained their capacity to synthesize glycoproteins for at l... |
616491 | Regulation of glucose carriers in chick fibroblasts. | The derepression of glucose transport initiated by removing glucose from the incubation medium requires both protein and RNA synthesis. The synthesis and accumulation of putative mRNA for the carrier protein(s) can be demonstrated by inhibiting protein synthesis with cycloheximide (2 microgram/ml). Release from inhibit... |
616490 | The structure of intrinsic membrane proteins. | Intrinsic membrane proteins are embedded in the lipid bilayer so that the polypeptides come in contact with the non-polar region of the bilayer. There are two major types of intrinsic proteins: those with most of their mass outside the cytoplasm (Type I) and those with most of their mass inside the cytoplasm (Type II).... |
567720 | Reconstitution of neutral amino acid transport from partially purified membrane components from Ehrlich ascites tumor cells. | Solubilized protein fractions have been obtained from plasma membranes of Ehrlich ascites cells either by extraction with 0.5% Triton X-100 or by extraction with 2% cholate. Partial purification of the solubilized protein fraction has been obtained by utilizing a combination of ammonium sulfate precipitation and column... |
357845 | The molecular mechanism of dicarboxylic acid transport in Escherichia coli K 12. | It is the purpose of this communication to review the properties of the dicarboxylic acid transport system in Escherichia coli K 12, in particular the role of various dicarboxylate transport proteins, and the disposition of these components in the cytoplasmic membrane. The dicarboxylate transport system is an active pr... |
357844 | Energetics and molecular biology of active transport in bacterial membrane vesicles. | Bacterial membrane vesicles retain the same sidedness as the membrane in the intact cell and catalyze active transport of many solutes by a respiration-dependent mechanism that does not involve the generation of utilization of ATP or other high-energy phosphate compounds. In E. coli vesicles, most of these transport sy... |
211349 | Small-angle x-ray scattering study of human serum low-density lipoproteins with differential reactivity for an arterial proteoglycan. | The structure and thermal behavior of human serum low-density lipoproteins showing either a high or a low reactivity against a proteoglycan isolated from human arteries have been found to be different from each other. It is suggested that modifications in the lipoprotein surface structure induced by the physical state ... |
616489 | An electron microscopic and enzymic study of rat liver peroxisomal nucleoid core and its association with urate oxidase. | The appearance of the characteristic crystalloid core of rat liver peroxisomes is emulated by the electron microscopic (EM) appearance of highly purified urate oxidase prepared from the same tissue. The purity of the enzyme preparation was established by gel electrophoresis under various conditions and the specific enz... |
616488 | The turnover of a tissue specific cell surface ligand which inhibits lectin induced capping. | Ten-day-old embryonic chick neural retina release into the environment glycoprotein ligands which bind to homologous cells, inhibiting the lectin-induced redistribution of cell surface receptors. Material with identical activity is released from trypsin-dissociated neural retina cells that are allowed to repair in cult... |
616487 | Synthesis, secretion, and attachment of LETS glycoprotein in normal and transformed cells. | LETS glycoprotein is a surface glycoprotein which is absent or greatly diminished on the surfaces of transformed cells. Normal cells secrete large amounts of this protein into the medium; transformed cell medium contains much less. The difference is not due to degradation of the soluble LETS protein. Biosynthesis of LE... |
616486 | The biosynthesis of mannolipids and mannose-containing complex glycans by the retina. | Large-scale incubations were carried out with homogenates of the retinas of the 15--16-day-old chick embryo in the presence of GDP[U-14C] mannose, from which there were isolated mannolipid (Lipid I), oligosaccharide-lipids (Lipid II), and glycoprotein (residue). These incubations were performed in the presence of endog... |
616485 | Comparison of the carbohydrate of Sinbis virus glycoproteins with the carbohydrate of host glycoproteins. | The carbohydrate portions of the Sindbis virus glycoproteins were compared with the carbohydrate portions of cell surface glycoproteins from uninfected host cells. Comparisons of the size of glycopeptides were made using gel filtrations. Comparisons of sugar linkages were made by methylation analysis. The conclusion wa... |
211348 | Membrane assembly: synthesis and intracellular processing of the vesicular stomatitis viral glycoprotein. | The glycoprotein (G) of vesicular stomatitis virus (VSV) is synthesized on membrane-bound polyribosomes. Approximately 30 min after its synthesis, it reaches the surface plasma membrane where it is incorporated into budding virus. The first part of this paper focuses on the 2 intracellular, membrane-bound, glycosylated... |
99603 | Organization and polysaccharides of sponge aggregation factor. | Aggregation factor, the macromolecular complex which mediates species-specific aggregation of dissociated sponge cells, was isolated from several species, partially characterized, and visualized by electron microscopy. All factors were large fibrous complexes with a backbone and side chains or arms. In some factors, th... |
357843 | Surface antigens of the embryonic chick myoblast: expression on freshly trypsinized cells. | Using an antiserum raised in rabbits against embryonic chick skeletal myoblasts (Anti-M-24), we have examined the trypsin and neuraminidase sensitivity and physiological expression of myoenic cell surface antigens. It was found that trypsin-released muscle cells more effectively inhibited, on a cell to cell basis, the ... |
616484 | Cell surface changes accompanying myoblast differentiation. | Myoblasts are mononucleated cells and associated with differentiation undergo cell fusion and become multinucleated. The current studies have examined cell surface dynamic changes of Concanavalin A lectin receptor mobility and the role of hormones in modulating myoblast differentiation. A uniform distribution of Con-A ... |
151172 | Interaction between cytoplasmic (Ca2+--Mg2+) ATPase activator and the erythrocyte membrane. | Human red blood cells (RBC) contain a cytoplasmic, nonhemoglobin protein which activates the (Ca2+-Mg2+)ATPase of isolated RBC membranes. Results presented in this paper confirm that activation of (Ca2+-Mg2+)ATPase is associated with binding of the cytoplasmic activator to the membrane. Binding of the cytoplasmic activ... |
616483 | Reconstitution of D-glucose transport in vesicles composed of lipids and intrinsic protein (zone 4.5) of the human erythrocyte membrane. | Elucidation of the mechanism of facilitated D-glucose transport in human erythrocytes is dependent on the identification and isolation of the membrane protein(s) mediating this process. Based on the fact that stereospecific D-glucose transport is reconstituted in liposomes prepared by sonication of a lipid suspension w... |
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