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177814 | DNA synthesis in cultured human fibroblasts: regulation by 3':5'-cyclic AMP. | The addition of serum to density-inhibited human fibroblast cultures induced a wave of DNA synthesis, measured as [3H] thymidine incorporation into acid-precipitable material, beginning after 8-12 hr and reaching maximum levels of 16-24 hr. Addition of dibutyryl-3':5'-cyclic AMP (DBcAMP) together with serum inhibited [... |
1263509 | The cytochemical localization of adenylate cyclase activity in mucous and serous cells of the salivary gland. | The present study was undertaken to localize adenylate cyclase activity in salivary glands by cytochemical means. For the study, serous parotid glands and mixed sublingual glands of the rat were used. Pieces of the fixed glands were incubated with adenosine triphosphate (ATP) or adenylyl-imidodiphosphate (AMP-PNP) as s... |
177813 | ATP-stimulated transmitter release and cyclic AMP synthesis in isolated chromaffin granules. | ATP stimulates chromaffin granules from the bovine adrenal medulla to release epinephrine and specific soluble proteins. ATP analogs substituted in the beta-gamma position with either nitrogen or carbon were also found to be effective at inducing release from isolated chromaffin granules. However, an ATP analog substit... |
1263508 | The exchange of erythrocyte membrane phospholipids with rat liver extracts in vitro. | Intact rat or human erythrocytes and their isolated (ghost) membranes were incubated with the high speed supernatant fraction of homogenates derived from 32P-labeled rat livers. Phospholipid molecules were transferred between the red cell membranes and the liver extracts, as reflected by the convergence of their specif... |
1263507 | Heterogeneity in the conformation of different protein fractions from the human erythrocyte membrane. | We have isolated 5 families of proteins from human red blood cell membranes and characterized their secondary structure by ultraviolet circular dichroism measurements. The protein families were prepared by selective solubilization from ghosts under nondenaturing conditions. We find that the intact ghost has a mean alph... |
4657 | Proteins of the hepatoma tissue culture cell plasma membrane. | The specificity of lactoperoxidase-catalyzed iodination for the proteins of the hepatoma tissue culture cell plasma membrane was examined by histochemical, biochemical, and cell fractionation techniques. Light microscope autoradiography of sectioned cells shows the incorporated label to be localized primarily at the pe... |
176537 | Structure and function of cholera toxin and hormone receptors. | The enterotoxin from Vibrio cholerae is a protein of 100,000 mol wt which stimulates adenylate cyclase activity ubiquitously. The binding of biologically active 125I-labeled choleragen to cell membranes is of extraordinary affinity and specificity. The binding may be restricted to membrane-bound ganglioside GM1. This g... |
943675 | Binding to specific receptors on oocyte plasma membranes by serum phosvitin-lipovitellin. | Specific binding sites for the serum complex of phosvitin and lipovitellin have been shown to exist on the outer surface of rapidly growing chicken oocytes. The existence and specificity of these sites were demonstrated by competition for binding to unfixed oocyte membrane fragments and by displacement of already bound... |
176536 | Chromosomally depleted interspecific hybrid cell clones selected with cytotoxic antisera: utilization in the study of control of murine leukemia virus host-range. | A chromosomally stable mouse-Chinese hamster hybrid cell line was subjected to five rounds of selection with cytotoxic antisera raised in rabbits against either the parental mouse 3T3 cells or the parental Chinese hamster Wg-1 cells. Routine karyological analysis of clones isolated at each stage of serum selection reve... |
56527 | Fibroblast surface antigen (SF): molecular properties, distribution in vitro and in vivo, and altered expression in transformed cells. | We have recently described a cell type-specific surface (SF) antigen that is deleted in chick fibroblasts transformed by Rous sarcoma virus, SF antigen is a major surface component and makes up about 0.5% of the total protein on normal cultured fibroblasts. The antigen is shed from normal cells and is present in circul... |
1256062 | The size of adenylate cyclase and guanylate cyclase from the rat renal medulla. | The size distribution of adenylate cyclase from the rat renal medulla solubilized with the nonionic detergents Triton X-100 and Lubrol PX was determined by gel filtration and by centrifugation in sucrose density gradients made up in H2O or D2O. The physical parameters of the predominant form in Triton X-100 are s20,w, ... |
176535 | Nonrandom distribution of receptors for melanocyte-stimulating hormone on the surface of mouse melanoma cells. | An improved bubble method was developed for applying an ultrathin layer of nuclear track emulsion on the surface of cells labeled with I125-MSH. The autoradiographs of I125-MSH binding indicate a nonrandom distribution of receptors on the surface of mouse melanoma cells. It is suggested that MSH receptors are displayed... |
1256061 | The expression and localization of surface neoantigens in transformed and untransformed cultured cells infected with avian tumor viruses. | The presence and localization of neoantigens induced in cultured cells, infected or transformed with avian tumor viruses (ATV), were studied ultrastructurally on carbon platinum replicas of cell surfaces. The use of antibody, labeled with hemocyanin molecules, provided sensitive detection and analysis of cell surface a... |
1256060 | Cell surface receptors and their dynamics on toxin-treated malignant cells. | The binding, mobility, and mode of cell entry of the plant toxin ricin (or RCAII) were investigated on susceptible and partially resistant murine cell lines. When susceptible cells (SV40-transformed 3T3 fibroblast cells and BW5147 lymphoma cells) were examined, ricin bound rapidly, induced endocytosis, and entered the ... |
176534 | The effect of transformation-defective avian oncornavirus mutants on tumor antigen expression. | The recent isolation of conditional (temperature sensitive) and nonconditional transformation-defective mutants of avian sarcoma virus strains has facilitated the investigation of the effect of virus transformation on the cell's phenotype, e.g., with respect to morphology, growth pattern, or cell surface antigenicity. ... |
1256059 | Selective modification of cell surface proteins and thymidine transport in hamster cells exposed to cholera toxin. | The increased adherence and morphological response which occurs in Chinese hamster ovary cells as a result of exposure to cholera toxin is paralleled by modification in the relative exposure of outer proteins. Mild proteolysis treatment of the cells prelabeled with [3H] glucosamine reveals a markedly different kinetics... |
130516 | Concanavalin A perturbation of membrane enzymes of mammary gland. | The plant lectin concanavalin A (Con A) specifically inactivates the 5'-nucleotidase of a plasma membrane-enriched fraction from lactating mammary gland. The lectin also causes an activation of the membrane Mg++-ATPase, but does not affect galactosyltransferase or alkaline phosphatase. The enzyme perturbations are prev... |
1256058 | Investigations of the possible role of proteases in altering surface proteins of virally transformed hamster fibroblasts. | Virally transformed fibroblasts have on their surfaces zero or reduced amounts of a large external transformation-sensitive (LETS) glycoprotein. This protein is extremely sensitive to proteolysis. When prelabeled normal fibroblasts are cocultivated with transformed cells, the LETS glycoprotein of the normal cells shows... |
1247741 | Experience of coronary care in diabetes. | During 1968-1973, 94 patients with diabetes were admitted to a coronary care unit (CCU) on 99 occasions with proved myocardial infarction. Altogether 24 of them (25-5%) died, giving an overall mortality at the time of discharge of 24% for the total admissions. This was just significantly higher than the 19% mortality r... |
174735 | Differences between cytosol receptor complexes with corticosterone and dexamethasone in hippocampal tissue from rat brain. | The binding of [3H]corticosterone and [3H]dexamethasone to soluble macromolecules in cytosol of the hippocampal region of the brain has been studied in adrenalectomized male rats. Unlabeled dexamethasone appears to be a less effective competitor than corticosterone in the binding of [3H]corticosterone, while both unlab... |
1061127 | Magnetic circular dichroism of ferrous carbonyl adducts of cytochromes P-450 and P-420 and their synthetic models: further evidence for mercaptide as the fifth ligand to iron. | Absorption and magnetic circular dichroism (MCD) spectra have been obtained for the ferrous carbonyl adducts of cytochromes P-450 and P-420 as well as synthetic model systems. Ferrous porphyrins with sodium methyl mercaptide and CO in benzene give MCD and absorption spectra which are almost identical to those of the na... |
1061125 | Carbohydrate moieties of procollagen: incorporation of isotopically labeled mannose and glucosamine into propeptides of procollagen secreted by matrix-free chick embryo tendon cells. | Cells obtained from chick embryo tendons incorporate isotopically labeled glucosamine and mannose into the pro-alpha1 and pro-alpha2 chains of procollagen as judged by sodium dodecyl sulfate-gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The label was further localized to the propeptides ... |
128562 | The Raji cell radioimmune assay for detecting immune complexes in human sera. | A sensitivie and simple procedure for the detection and quantitation of soluble complement (C)- fixing immune complexes in sera of patients with various disease states has been developed by utilizing C receptors on Raji cells. These cells lack membrane-bound immunoglobulin but have receptors for IgG Fc, C3b, C3d, and p... |
1245458 | Substructure and in vitro assembly of the outer, structured layer of Spirillum serpens. | Electron micrographs of disintegrating units of the outer, structured (HP) layer of Spirillum serpens and of the isolated protein obtained from the HP layer revealed V- and Y-shaped and linear profiles. Interpretation of these forms, influenced by the seemingly trimeric form of the isolated protein and by biochemical d... |
53267 | Expression of individual Ia specificities on T and B cells. I. Studies with mitogen-induced blast cells. | Ia specificities 1-10 were detected on LPS-stimulated splenic lymphocytes and on Con A-stimulated spleen, lymph node, and thymus blasts by direct cytotoxic tests. Since Ia antigens are not readily detectable on resting thymocytes, our results suggest that T cells require some signal before they exhibit full expression ... |
127797 | Studies on the fatty acid inactivation of phosphofructokinase. | Investigation of phosphofructokinase in normal and regenerating livers led to the discovery of an inactivating factor in the extracts of these livers. The inactivating factor was found to be a mixture of free fatty acids. The fatty acid compositions of the normal and regenerating livers are the same, but the concentrat... |
24424767 | A structural glycoprotein, containing hydroxyproline, isolated from the cell wall of Chlamydomonas reinhardii. | A soluble extract from purified cell walls of C. reinhardii has been separated by gel filtration into three fractions which together account for 94% of the cell wall. The major fraction (accounting for 70% of the extract) is a glycoprotein, with a molecular wt. in sodium perchlorate of 298,000, which can be split into ... |
612443 | Effect of enzyme induction on nephrotoxicity of halothane-related compounds. | Nephrotoxicity following administration of methoxyflurane has been shown to be directly related to anesthetic metabolism to inorganic fluoride. Enzyme induction should increase metabolic rate and the amount of inorganic fluoride that is released. In vivo studies in Fischer 344 rats show that enzyme induction with pheno... |
341886 | Incorporation of methionine-derived methyl groups into sirohaem by Escherichia coli. | Sirohaem is a new type of haem that has been detected as a prosthetic group of several bacterial and plant enzymes that catalyse the six-electron reductions of sulphite to sulphide or of nitrite to NH(3). When a methionine-requiring mutant of Escherichia coli K12 was grown on a minimal medium supplemented with d-glucos... |
603621 | The separation and characterization of bronchial glycoproteins by density-gradient methods. | 1. Sputum samples from a total of 18 asthmatic and chronic bronchitic patients were examined by analytical density-gradient ultracentrifugation. CsBr was used as the dispersal agent and dense electrolyte. 2. The patterns show two main groups of components, banding at about 1.3g/ml and 1.5g/ml; in addition, a few sample... |
271974 | New method for localizing proteins in periodic structures: Fab fragment labeling combined with image processing of electron micrographs. | Fab fragments prepared from antisera directed against purified bacteriophage T4 structural proteins and head-related structures were used to label proteins on the surface of T-even giant phage capsids. Optically filtered electron micrographs of the Fab-labeled capsids reveal both the location of specific proteins withi... |
202954 | Guanosinetriphosphatase activity of tubulin associated with microtubule assembly. | Tubulin, purified by cycles of assembly followed by phosphocellulose chromatography, exhibits a characteristic GTPase activity that is polymerization dependent and can be attributed to the tubulin itself. This activity has been observed, in a standard reassembly buffer containing low Mg2+, under three conditions that i... |
414220 | Method for detection of specific RNAs in agarose gels by transfer to diazobenzyloxymethyl-paper and hybridization with DNA probes. | We describe a technique for transferring electrophoretically separated bands of RNA from an agarose gel to paper strips. The RNA is coupled covalently to diazobenzyloxymethyl groups on the paper. After transfer and appropriate treatment of the paper to destroy remaining diazo groups, specific RNA bands can be detected ... |
563478 | Binding characteristics of Rauscher leukemia virus envelope glycoprotein gp71 to murine lymphoid cells. | The major envelope glycoprotein (gp71) purified from Rauscher leukemia virus (R-MuLV) binds efficiently to murine lymphoid cells but not to either murine nonlymphoid cells or lymphoid cells from other species. Binding of 125I-labeled R-MuLV gp71 was competitively inhibited by unlabeled glycoprotein, as well as by whole... |
562890 | Assembly of smooth muscle myosin into side-polar filaments. | The in vitro assembly of myosin purified from calf aorta muscle has been studied by electron microscopy. Two types of filament are formed: short bipolar filament similar to those formed from skeletal muscle myosin, and longer "side-polar" filaments having cross bridges with a single polarity along the entire length of ... |
144531 | The formation of phosphoenzyme of sarcoplasmic reticulum. Requirement for membrane-bound Ca2+. | Membrane-bound Ca or Mg of sarcoplasmic reticulum fragments were removed by treating the membrane with EDTA or an acidic solution, and the changes in the enzymatic activities of sarcoplasmic reticulum fragments induced by these treatments were examined. With the decrease in the amount of membrane-bound Ca below 1-3-10(... |
343723 | Diagnosis of acute bacterial pneumonia in Nigerian children. Value of needle aspiration of lung of countercurrent immunoelectrophoresis. | Eighty-eight Nigerian children with untreated, severe, acute pneumonia were investigated by standard bacteriological techniques (blood culture and culture of pharyngeal secretions) and by needle aspiration of the consolidated lung. Countercurrent immunoelectrophoresis (CIE) against grouped pneumococcal and Haemophilus ... |
23107 | Characterization and serology of the matrix protein from a nuclear-polyhedrosis virus of Trichoplusia ni before and after degradation by an endogenous proteinase. | The intact matrix protein from a nuclear-polyhedrosis virus of the cabbage looper (Trichoplusia ni), isolated after inhibition of an endogenous serine-type proteinase, was further purified by molecular-sieve chromatography. The matrix protein was associated with carbohydrate moieties, and the carbohydrate content was d... |
337309 | Domains involving nonrandom distribution of lipopolysaccharide in the outer membrane of Escherichia coli. | The present data demonstrate that the outer membrane of Escherichia coli contains domains of lipopolysaccharide that do not intermix freely with each other. A strain of E. coli lacking galactose epimerase was grown with galactose, for varying periods of time, which permits formation of a long polysaccharide, and withou... |
337301 | Escherichia coli ribosomal protein S1 has two polynucleotide binding sites. | The interaction of Escherichia coli ribosomal protein S1 with a variety of RNA and DNA oligomers and polymers has been studied, using both a sedimentation technique and the quenching of intrinsic protein fluorescence upon nucleic acid binding to obtain equilibrium binding parameters. Two polynucleotide binding sites ha... |
21305 | Properties of deoxynucleoside 5'-monophosphatase induced by bacteriophage T5 after infection of Escherichia coli. | Bacteriophage T5 induced a deoxynucleoside 5'-monophosphatase during its infection of Escherichia coli. The enzyme was purified about 100-fold. It was clearly distinct from the host 5'-nucleotidase activity in its physical characteristics and substrate specificity. The enzyme was active on deoxynucleoside 5'-monophosph... |
410808 | Mechanism of palmityl coenzyme A inhibition of liver glycogen synthase. | Palmityl-CoA inhibits free liver glycogen synthase; the concentration required for half-maximum inhibition is 3 to 4 micrometer. Almost complete inhibition was observed at 50 micrometer. Palmityl-CoA inhibition is associated with dissociation of the tetrameric enzyme into monomers, and binding of palmityl-CoA to the mo... |
198432 | Collagen-mediated platelet aggregation. Evidence for multivalent interactions of intermediate specificity between collagen and platelets. | We have shown previously that periodate oxidation of collagen carbohydrate does not affect its ability to aggregate platelets. We now describe an additional characterization of periodate-modified collagen which demonstrates that collagen devoid of intact carbohydrate is fully capable of fibril formation, and we confirm... |
233748 | Is there a role for actin in virus budding? | Electrophoretic data from both sodium dodecyl sulfate-polyacrylamide gels (SDS-PAGE) and acid-urea gels reveal a protein in purified murine mammary tumor virus (MuMTV) which co-migrates with purified chick skeletal muscle actin. 125I-labeling of intact and disrupted virus preparations shows that the actin-like protein ... |
264118 | Isolation and characterization of the vitelline layer of sea urchin eggs. | The vitelline layers (VLs) of unfertilized sea urchin eggs were isolated by homogenization in a hypotonic medium containing Triton X-100 and EDTA. The surface topography of the VL is not changed by isolation. The thickness of the isolated VLs (300-400 A) is greater than that reported for VLs on intact eggs (100-200 A).... |
16592462 | Biogenic amine-ionophore interactions: Structure and dynamics of lasalocid (X537A) complexes with phenethylamines and catecholamines in nonpolar solution. | The ionophore lasalocid A forms 1:1 complexes with phenethylamines (1-amino-1-phenylethane and 1-amino-2-phenylethane) and catecholamines (dopamine and norepinephrine) in nonpolar solution. We have undertaken high-resolution proton nuclear magnetic resonance studies to deduce structural and kinetic information on the i... |
579316 | [A comparative ultrastructural-morphometric study of the cochlear spiral ganglion in rats and guinea pigs (author's transl)]. | The cochlear spiral ganglion of rats consists of 61.8% granular ganglion cells, 22.4% satellite cells and Schwann cells, 9.3% extracellular space, 4.8% myelinated nerve fibers and 1.4% filamentous ganglion cells. The granular ganglion cells consist of 76% cytoplasmic components and 24% nuclei. Their cytoplasm contains ... |
337240 | Complex formation between ribosomal protein S1, oligo-and polynucleotides: chain length dependence and base specificity. | In order to examine the nature of the complex formation between the ribosomal protein S1 and nucleic acids three methods were used: Inhibition of the reaction of n-ethyl[2.3 14C]-maleimide with S1 by the addition of oligonucleotides; adsorption of the complexes to nitrocellulose filters; and equilibrium dialysis. The c... |
923572 | Differences in the modulations of the soluble of plasma-membrane-bound 5'-nucleotidase. | The treatment of plasma membranes by a French pressure cell in sucrose medium devoid of detergents solubilized 20% of the total protein and 95--100% of 5'-nucleotidase activity. The soluble enzyme was 40--90-fold purified by centrifugation in a sucrose gradient with a 10--20% yield with respect to the orginal lysate. T... |
334259 | The dynamic structure of the Escherichia coli cell envelope as probed by 15N nuclear magnetic resonance spectroscopy. | Proton decoupled 15N NMR spectroscopy is shown to be a useful tool for probin the dynamic structure of the bacterial cell envelope. The proton decoupled 15N NMR spectra of Escherichia coli whole cells, cell envelopes and outer membranes were obtained and displayed resonances originating from protein side-chain groups, ... |
911827 | Theory of self-assembly of lipid bilayers and vesicles. | A simple theory is developed that explains the formation of bilayers and vesicles and accounts quantitatively for many of their physical properties: Properties including vesicle size distributions and bilayer elasticity emerge from a unified theory that links thermodynamics, interaction free energy, and molecular geome... |
302311 | In vitro analysis of allogeneic lymphocyte interaction. I. Characterization and cellular origin of an Ia-positive helper factor-allogeneic effect factor. | A soluble allogeneic effect factor (AEF) was produced by using H-2 congenic mouse strains and a serum.free cell culture medium. An AEF derived from untreated activated responder cells and irradiated stimulator cells provided helper cell function in a primary and secondary antibody response for both T-cell-depleted resp... |
73233 | Staining myelin in brain with gallein: a new method. | A procedure is described in which gallein, mordant violet 25, C.I. 45445, is used to demonstrate myelinated nerve fibers in animal brain. Specimens are fixed in 10% neutral buffered formalin and processed in a routine manner. Microsections are stained in an iron gallein solution with subsequent differentiation in 0.25%... |
72077 | Histopathological occurrence and characterisation of calcium oxalate: a review. | Oxalosis is the histological manifestation of a number of diverse clinicopathological states involving abnormalities of both endogenous and exogenous oxalate. Crystalline deposits of calcium oxalate, usually first detected by their birefringence, may be characterised by a combination of their physical and tinctorial pr... |
909797 | Complex mitochondrial DNA in Drosophila. | The larval mtDNA isolated from D. virilis, D. simulans and D. melanogaster exists in complex molecular forms in addition to the simple monomeric circular form. The frequency of circular dimers and oligomers is highly elevated in apparently normal larval tissues. These complex forms of mtDNA are separable on agarose gel... |
20447 | The contractile basis of amoeboid movement. V. The control of gelation, solation, and contraction in extracts from Dictyostelium discoideum. | Motile extracts have been prepared from Dictyostelium discoideum by homogenization and differential centrifugation at 4 degrees C in a stabilization solution (60). These extracts gelled on warming to 25 degrees Celsius and contracted in response to micromolar Ca++ or a pH in excess of 7.0. Optimal gelation occurred in ... |
71303 | Myosin subfragment binding for the localization of actin-like microfilaments in cultured cells. A light and electron microscope study. | Fluorescein-labeled heavy meromyosin subfragment-1 (F-S-1) has been purified by ion exchange chromatography and characterized in terms of its ability to bind specifically to actin. F-S-1 activates the Mg++-adenosine triphosphatase activity of rabbit skeletal muscle actin and decorates actin as shown by negative stains ... |
561787 | Heat-induced reversible hexagonal packing of spindle microtubules. | Epithelial cells cultured from the lung of the Northwest rough-skinned newt (Taricha granulosa granulosa) were subjected to brief (10-15 min) elevated temperature shocks of 33 degrees-36 degrees C during metaphase. Electron microscope studies on these cells reveal that the spindle microtubules (Mts) are differentially ... |
409673 | Heterogeneity of nonimmune immunoglobulin Fc reactivity among gram-positive cocci: description of three major types of receptors for human immunoglobulin G. | Two hundred and thirty strains of various gram-positive cocci were tested for quantitative, nonimmune binding of radiolabeled human polyclonal immunoglobulin G (IgG). The majority of coagulase-positive staphylococci and streptococci belonging to serogroups C and G showed a high uptake of IgG. The binding of immunoglobu... |
901783 | Refinement of the fluid-mosaic model of membrane structure. | Certain molecular packing criteria previously employed in a quantitative analysis of lipid micelles and bilayers are here extended to biological membranes. The inclusion of both thermodynamic and packing considerations point to a highly complex self-assembly mechanism in which the organization of lipids and proteins is... |
197269 | Dissociation of polyoma virus by the chelation of calcium ions found associated with purified virions. | Analysis of polyoma virions by X-ray fluorometry demonstrated that calcium (Ca2+) was associated with the purified virion. Treatment of purified virions with ethyleneglycol-bis-N,N'-tetraacetic acid (EGTA), which chelates Ca2+, and the reducing agent dithiothreitol caused the virions to dissociate. Electron microscopy ... |
19111 | Properties and biodegradation of a bioemulsifier from Corynebacterium hydrocarboclastus. | An extracellular polymer was produced by continuous fermentation of Corynebacterium hydrocarboclastus on kerosene in a 24 liter reactor. This polymer was composed of protein, lipid, and carbohydrates. The polymer possessed surface active properties, and had two critical micelle concentrations. Its effectiveness was qui... |
889845 | Study on the mechanism of action of adenosylcobalamin-dependent glycerol dehydratase from Aerobacter aerogenes. I. Role of structural components of adenosylcobalamin the formation of the active site of glycerol dehydratase. | A new method of partial chemical synthesis of adenosylcobalamin (Co alpha-[alpha-5,6-diemethylbenzimidazolyl)]-Co beta-adenosylcobamide, AdoCbl) analogs has been developed. A series of derivatives of AdoCbl modified in the nucleoside and nucleotide ligands and corrin macrocycle have been obtained. The interaction of Ad... |
618344 | [Electron microscopy study of fibrin self-assembly]. | The process of fibrin selfassembly has been examined by electron microscopy. Its initial stage is found to consist in fibrin monomer conversion to thin filaments of random shape, probably identical with the well known intermediate polymers of fibrin. When the filaments attain an appropriate size they arrange themselfs ... |
921753 | Subtilisin modification of monodeamidated ribonuclease-A. | Limited proteolysis of RNAase-Aa(1) (monodeamidated ribonuclease-A) by subtilisin results in the formation of an active RNAase-S type of derivative, namely RNAase-Aa(1)S. RNAase-Aa(1)S was chromatographically distinct from RNAase-S, but exhibited very nearly the same enzymic activity, antigenic conformation and suscept... |
269406 | Addition of colchicine--tubulin complex to microtubule ends: the mechanism of substoichiometric colchicine poisoning. | Colchicine blocks microtubule polymerization by an unusual substoichiometric poisoning mechanism. We have investigated the mechanism by which this poisoning occurs with several experimental approaches, and have found that colchicine acts by addition to microtubule ends as a colchicine-tubulin complex. |
269403 | Random assembly of different kinds of small subunit polypeptides during formation of fraction I protein macromolecules. | Maternal inheritance determine the charge on the large subunit of fraction I protein whereas both parents of an interspecific F(1) hybrid plant make an equal contribution to the charge of the small subunit. Experiments were performed to test whether fraction I protein in the hybrid plant was a hybrid molecule or two ki... |
269394 | Thermodynamics of the self-association of glucagon. | In water, glucagon exists in an equilibrium between a trimer in which more than half of the peptide groups are in an alpha-helical configuration and a monomer which has a random coil configuration with few alpha-helical residues. The thermodynamics of this self-association have been evaluated by studying the temperatur... |
20622 | Fatty acid synthetase from Brevibacterium ammoniagenes: formation of monounsaturated fatty acids by a multienzyme complex. | A multienzyme fatty acid synthetase complex isolated from Brevibacterium ammoniagenes has been purified to a specific activity of 1440 nmol of malonyl-CoA incorporated per min/mg. The enzyme is homogeneous, as judged by gel electrophoresis on agarose gels, and has a molecular weight of 1.2 X 10(6). Both NADPH and NADH ... |
198773 | Enzyme associations in T4 phage DNA precursor synthesis. | A DIRECT APPROACH IS DESCRIBED TO THE QUESTION: Are enzymes of DNA precursor synthesis organized into a supramolecular structure? This approach involved sedimentation analysis of several T4 phage-coded early enzyme activities in crude lysates of infected Escherichia coli. One-third to one-half of several activities tes... |
560378 | Rearrangements of integral membrane components during in vitro aging of sheep erythrocyte membranes. | In vitro aged sheep erythrocytes and sheep erythrocyte ghosts spontaneously release vesicles that consist of long protrusions affixed to flattened headlike structures. The intramembranous particles seen on the protoplasmic face of freeze fracture electron micrographs of vesicle protrusions are arranged in paired partic... |
871526 | Reversal of granulocyte adherence to nylon fibers using local anesthetic agents: possible application to filtration leukapheresis. | The effects of the cationic anesthetic agents tetracaine and lidocaine on granulocyte function, morphology, and adherence to nylon fibers were studied in an attempt to improve current methods of granulocyte collection by filtration leukapheresis (FL). When dissolved in acid-citrate-dextrose (ACD) plasma, these drugs si... |
70787 | Cleavage of C2 by C1s into the antigenically distinct fragments C2a and C2b: demonstration of binding of C2b to C4b. | The activation of complement component C2 by C1s is a major reaction step leading to the assembly of two related macromolecular enzymes in the classical complement pathway C3 convertase and C5 convertase. The present studies clearly document the smaller fragment, C2b, that results when human C2 reacts with C1s. We have... |
331320 | Mobility and distribution of a cell surface glycoprotein and its interaction with other membrane components. | Fluorescence photobleaching recovery and immunofluorescence methods have been used to study the lateral mobility and topographical distribution of a major cell surface glycoprotein (CSP). Both endogenous CSP and fluorescent-labeled exogenous CSP bind to the cell surface in a fibrillar pattern and are immobile on the ex... |
197515 | Excited state lifetimes in cytochromes measured from Raman scattering data: evidence for iron-porphyrin interactions. | Resonance Raman scattering excitation profile data have been obtained on ferrocytochromes c and b5 in the alpha absorption band region. We observe in cytochrome c that the shape of the excitation profile agrees with the absorption band shape, while in cytochrome b5 it does not. In addition, we observe in cytochrome b5 ... |
889329 | Numerical taxonomy and ecology of petroleum-degrading bacteria. | A total of 99 strains of petroleum-degrading bacteria isolated from Chesapeake Bay water and sediment were identified by using numerical taxonomy procedures. The isolates, together with 33 reference cultures, were examined for 48 biochemical, cultural, morphological, and physiological characters. The data were analyzed... |
328926 | Further studies on bacteriophage T4 DNA synthesis in sucrose-plasmolyzed cells. | This paper describes several technical improvements in the sucrose-plasmolyzed cell system used in earlier experiments on DNA synthesis in situ with Escherichia coli infected by DNA-defective mutants of bacteriophage T4 (W. L. Collinsworth and C. K. Mathews, J. Virol. 13:908-915, 1974). Using this system, which is base... |
196105 | Ammonium chloride inhibits cell fusion induced by syn mutants of herpes simplex virus type 1. | Cell fusion induced by syn mutants of herpes simplex virus type 1 is inhibited by NH4Cl. The inhibition of fusion is both rapid and rapidly reversible and apprears to be due to the NH4+ ion. Virus production was not significantly altered by NH4Cl, although cell growth was greatly diminished. |
885614 | Survey of the extrachromosomal gene pool of Streptococcus mutans. | Fifty strains of Streptococcus mutans independently isolated from human dental plaque were examined for the presence of covalently closed circular plasmid deoxyribonucleic acid (DNA). Cesium chloride-ethidium bromide centrifugation of [3H]thymidine-labeled, Sarkosyl-lysed cells revealed that 2 of the 50 strains contain... |
874075 | The rate of synthesis of glycosaminoglycans and collagen by fibroblasts cultured from adult human liver biopsies. | Adult human liver biopsies were cultured from normal, alcoholic hepatitis, chronic active hepatitis, fibrosis plus alcoholic hepatitis (active cirrhosis), inactive cirrhosis, and drug hepatitis. The synthesis of collagen was estimated in cultures from 58 livers by measuring the conversion of [(14)C]proline to the [(14)... |
30241432 | An unusual cytoplasmic organelle in oocytes of Ilyanassa obsoleta. | An unusual organelle in the oocytes of the marine mud snail Ilyanassa obsoleta is described and called a polymerosome, because of its several components. Polymerosomes appear at the beginning of vitellogenesis and persist, in part, through postvitellogenesis. The persistent part is similar to an organelle that has been... |
331264 | Inhibition of transcription of supercoiled PM2 DNA by carbodiimide modification. | PM2 superhelican DNA (form I), which as been reacted with the single strand specific reagent, N-cyclohexyl-N'-beta-(methylmorpholinium)ethyl carbodiimide (CMC) is more than 95% inhibited in its ability to support transcription with E. coli B RNA polymerase in vitro. Almost complete inhibition of transcription was achie... |
890027 | A mechanism for the entrapment of DNA at an air-water interface. | Addition of the intercalating dye quinacrine to a low ionic strength solution of DNA in quantities sufficient to saturate the high affinity sites in the DNA will result in the accumulation of the DNA at the solution interface. This entrapment of DNA at the air-water interface has been assayed by the adsorption of DNA t... |
329277 | Inactivation and proteolytic cleavage of phage lambda repressor in vitro in an ATP-dependent reaction. | We have reproduced in vitro the inactivation of bacteriophage lambda repressor that occurs in vivo when a lambda lysogen is treated with agents such as ultraviolet radiation that attack DNA. ATP and a divalent cation are required for the inactivation reaction. The ind- repressor is insensitive to the inactivation mecha... |
142250 | Uncouplers and the molecular mechanism of uncoupling in mitochondria. | Uncouplers are molecules with protonophoric and ionophoric capabilities that mediate coupled cyclical transport of cations--a transport that takes precedence over all other coupled processes. Uncouplers form cation-containing complexes with electrogenic ionophores that potentiate cyclical transport of cations. The mole... |
195576 | A comparison of the association of yeast phosphoglycerate mutase (EC2.7.5.3) with that of haemoglobin. An ultracentrifuge study. | 1. Previous work showed that yeast phosphoglycerate mutase (EC 2.7.5.3) has a mol.wt. of between 107000 and 110000. Preliminary examination showed that at dilutions less than 0.1 g/1 the enzyme dissociated into its subunits. 2. This dissociation was quantitatively examined by both equilibrium and velocity centrifugatio... |
559676 | The pericentriolar material in Chinese hamster ovary cells nucleates microtubule formation. | The structure and function of the centrosomes from Chinese hamster ovary (CHO) cells were investigated by electron microscopy of negatively stained wholemount preparations of cell lysates. Cells were trypsinized from culture dishes, lysed with Triton X-100, sedimented onto ionized, carbon-coated grids, and negatively s... |
892079 | [Restoration of the electrical activity and nervous apparatus following section of the stomach wall in dogs]. | In dogs, transection of the gastric wall at the level of incisura angularis, followed by end--to--end anastomosis, was made. The electrodes were implanted into the muscle wall of the two stomach segments. Electrical activity of the stomach wall on the 1st postoperative day showed dissociation in the spike activity betw... |
880253 | Self-digestion of human erythrocyte membranes. Role of adenosine triphosphate and glutathione. | Intact human erythrocytes incubated at 37 degrees C, pH7.4, release a sialoglycopeptide similar in its chemical composition, immunological and aggregation properties to the glycopeptide released by isolated 'ghost' membranes. The presence of ATP or reduced glutathione at physiological concentrations in the incubation m... |
874756 | Utilization of cyclodextrin complexation for separation of E, A, and B prostaglandins by ion-exchange liquid chromatography. | Application of cyclodextrin complexation to the separation of E-, A-, and B-type prostaglandins by ion-exchange liquid chromatography is demonstrated. The addition of alpha-or beta-cyclodextrin into the mobile phase on an anion-exchange support decreased the retention times of the prostaglandins significantly because o... |
194248 | Biogenesis of poxviruses: analysis of the morphogenetic sequence using a conditional lethal mutant defective in envelope self-assembly. | A conditional lethal, temperature-sensitive mutant of vaccinia, defective in assembly of the virus envelope and maturation, was characterized and shown to mimic exactly the aberrations produced by rifampicin. Analyses of the infection at restrictive and permissive temperatures were conducted with electron microscopy, i... |
266719 | Disagreement between calorimetric and van't Hoff enthalpies of assembly of protein supramolecular structures. | The effect of temperature on the extent of association of self-assembling protein polymers is expressed mathematically in terms of the van't Hoff enthalpy of polymerization, deltaHV.H. This quantity has been experimentally defined in two ways--from the respective temperature derivatives of the critical polymerization c... |
266708 | In vitro assembly of pure tubulin into microtubules in the absence of microtubule-associated proteins and glycerol. | Microtubule protein from porcine cerebrum was fractionate into pure tubulin and microtubule-associated proteins by chromatography on phosphocellulose. In agreement with previous studies, pure tubulin does not form microtubules to a significant extent at 37 degrees in normal assembly buffers, which are characterized by ... |
324916 | Interaction of lipoteichoic acid of group A streptococci with human platelets. | The interaction of group A streptococcal lipoteichoic acid (LTA) with mammalian cell membranes was studied in human platelets. The binding of LTA to platelets was platelet concentration and time dependent. Binding approached a maximum within 10 min of incubation. The bound LTA could be displaced by adding a 50-fold exc... |
861215 | Evidence for intermediate formation in the mechanism of potato starch -hosphorylase from exchange of the ester and phosphoryl oxygens of alpha-D-glucopyranose 1-phosphate. | We have examined under a variety of conditions the ability of potato starch phosphorylase to cause exchange of the ester and phosphoryl oxygens of alpha-D-glucopyranose 1-phosphate (Glc-1-P). In the presence of phosphorylase and strach, under conditions where 40-50% of the glc-1-P is consumed in starch elongation, litt... |
870619 | Fine structure of the cerebellum of "staggerer-reeler", a double mutant of mice affected by staggerer and reeler conditions. II. Purkinje cell anomalies. | Purkinje cells in double mutant were very similar to those in staggerer both at days 7 and 15, and could not be distinguished from staggerer Purkinje cells by morphological criteria. They were small and immature looking, and their nuclei were invariably eccentric in position both at days 7 and 15. The typical funnel st... |
870502 | Basal lamina of embryonic salivary epithelia. Nature of glycosaminoglycan and organization of extracellular materials. | The ultrastructural organization and the composition of newly synthesized glycosaminoglycan (GAG) in the epithelial basal lamina of mouse embryo submandibular glands were assessed. The labeled GAG accumulating in the lamina is distinct from that in its tissue of origin, the epithelium, or from that in the surrounding m... |
67603 | Identification of a purified complement-fixing antigen as the Epstein-Barr-virus determined nuclear antigen (EBNA) by its binding to metaphase chromosomes. | A soluble complement-fixing antigen carried by Epstein-Barr virus (EBV)-transformed human cells has been previously extracted from cell nuclei and purified by DNA-cellulose chromatography [Luka, J., Siegert, W. & Klein, G. (1977) J. Virol., in press]. On addition of this antigen to methanol/acetic acid-fixed metaphase ... |
266184 | Collagen degradation in rat skin but not in intestine during rapid growth: effect on collagen types I and III from skin. | Metabolic degradation of prelabeled collagen in whole body skin and whole intestine was compared to that of types I and III collagens from skin in young, rapidly growing rats. Pregnant rats were given [3H]proline during the last week of gestation; and after birth, littermates were compared. Between the second and sixth... |
266173 | Molecular description of dioxygen bonding in hemoglobin. | From ab initio quality calculations on model systems, we conclude that in unliganded Fe-porphyrin the FE lies in the plane for both the high-spin (q) and intermediate-spin (t) states. Thus, the high-spin d6 Fe is not too big to fit into the porphyrin plane (as often suggested). We find the q state lower for a porphyrin... |
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