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616162 | Regular folding chain conformation of the deoxyribonucleic acid in chromatin. X-ray diffraction and selforganization. | The following model is proposed for the structure of deoxyribonucleic acid (DNA) in chromatin: The DNA in a nucleosome is folded seven times to and fro on the surface of a cylindrical protein nucleus. There exist 3.5 DNA hairpins. The seven arms of the hairpins contain twenty DNA base pairs each. The six loops of the D... |
218169 | Selection of methionine tRNAs by avian oncornaviruses. | The free 4S RNA of avian RNA tumor viruses is greatly enriched in one of the four methionine tRNAs of the host cells, tRNA4Met. On the assumption that viral tRNAMet forms are identical to the corresponding tRNAs of mouse or chick cells, the following conclusions were drawn concerning the tRNAMet content of oncornavirus... |
370773 | A conserved and unique (AT)-rich segment in yeast mitochondrial DNA. | The mtDNA of the cytoplasmic petite mutant of yeast RD1A consists mainly of a perfect head-to-tail repetition of a known sequence of 66 consecutive AT and 2 GC base pairs. We have hybridized complementary RNA made on RD1A mtDNA with the mtDNAs of four different wild-type Saccharomyces strains that differ markedly in re... |
282604 | Interaction of bacteriophage lambda repressor with nonoperator DNA containing single-strand gaps. | In direct binding assays, purified lambdaind+ repressor displayed high affinity for nonoperator DNA containing single-strand gaps. Its affinity for this same DNA but completely double-stranded, nicked, or denatured was considerably lower. In contrast, purified lambdaind- repressor had 1/10th the affinity for the gapped... |
722476 | Phase solubility analysis and PMR study of complexing behavior of dinoprostone with beta-cyclodextrin in water. | The mechanism of inclusion compound formation by dinoprostone (prostaglandin E2) with beta-cyclodextrin was studied by phase solubility analysis and PMR spectroscopy. As indicated by the linear increase of aqueous solubility of dinoprostone with beta-cyclodextrin concentration, some types of molecular interactions defi... |
728526 | Dynamic light scattering from solutions of microtubules. | Calf brain microtubule protein was assembled in vitro to form dilute solutions of microtubules (240 A diameter) having lengths greater than 1 micrometer. The microtubule solutions were examined by dynamic laser light scattering techniques. The angular dependence of the correlation function leads to the conclusion that ... |
215240 | Large-scale rotational motions of proteins detected by electron paramagnetic resonance and fluorescence. | Direct spectroscopic measurements of rotational motions of proteins and large protein segments are crucial to understanding the molecular dynamics of protein function. Fluorescent probes and spin labels attached to proteins have proved to be powerful tools in the study of large-scale protein motions. Fluorescence depol... |
214789 | Rotational motion of the sarcoplasmic reticulum Ca2+-ATPase. | Using saturation transfer electron paramagnetic resonance, we have detected the rotational motion of a spin label rigidly attached to the sarcoplasmic reticulum Ca2+-ATPase (ATP phosphohydrolase, EC 3.6.1.3). At 4 degrees C, the spectrum indicates an effective rotational correlation time of 60 microsec, determined by c... |
82967 | Immunoreactivity and receptor binding of mixed recombinants of human growth hormone and chorionic somatomammotropin. | The behavior in six radioligand assays of the recombinant obtained by the noncovalent complementation of the reduced and carbamoylmethylated 134-residue amino-terminal fragment of human growth hormore with the reduced and carbamoylmethylated 51-residue carboxyl-terminal fragment of human chorionic somatomammotropin was... |
281676 | Energetics of enzyme catalysis. | Quantitative studies of the energetics of enzymatic reactions and the corresponding reactions in aqueous solutions indicate that charge stabilization is the most important energy contribution in enzyme catalysis. Low electrostatic stabilization in aqueous solutions is shown to be consistent with surprisingly large elec... |
569158 | The in vitro assembly of flagellar outer doublet tubulin. | Flagellar outer doublet microtubules were solubilized by use of sonication, and the tubulin was reassembled in vitro into single microtubules containing 14 and 15 protofilaments. The tubulin assembly was dependent on both the KCl and tubulin concentrations, exhibiting a critical concentration of 0.72 mg/ml at optimum s... |
569157 | Structure and biochemical composition of desmosomes and tonofilaments isolated from calf muzzle epidermis. | Complexes of plasma membrane segments with desmosomes and attached tonofilaments were separated from the stratum spinosum cells of calf muzzle by means of moderately alkaline buffers of low ionic strength and mechanical homogenization. These structures were further fractionated by the use of various treatments includin... |
81813 | Motor innervation of the urinary tract studied by retrograde axonal transport of protein. | A new method for tracing the nervous control of the bladder is described. A protein substance, horseradish peroxidase, has been shown to be absorbed and transported by nerve fibers. The substance was injected into the bladder neck region of a series of dogs. After uptake by motor neurons the horseradish was carried to ... |
688556 | Renal chemoreceptors in the rat. | There are afferent nerve fibers responsive to alterations of the kidney's chemical environment in the renal nerves of the rat. In anesthetized, artificially ventilated, male Sprague-Dawley rats, single unit recordings were prepared by dissection of the centrally cut nerves of the right kidney. The stimuli used included... |
16592579 | Bacteriochlorophyll electronic transition moment directions in bacteriochlorophyll a-protein. | The low-temperature 800-nm band absorption and circular dichroism spectra of the bacteriochlorophyll (Bchl) a-protein from Prosthecochloris aestuarii strain 2K are analyzed theoretically. These spectra show considerable structure that is attributed primarily to resonance (exciton) interactions among the lowest singlet ... |
368802 | Mechanism of action of the pyruvate dehydrogenase multienzyme complex from Escherichia coli. | The extent of cooperativity among the polypeptide chain components in the overall reaction catalyzed by the pyruvate dehydrogenase multienzyme complex from Escherichia coli has been studied. Selective inactivation of the pyruvate dehydrogenase component with thiamin thiazolone pyrophosphate demonstrates that no coopera... |
724501 | Study of DNA-spermine interactions by use of small-angle and wide-angle X-ray scattering and circular dichroism. | Circular dichroism measurements with DNA-spermine complexes at 0.075 M NaCl and at 0.15 M NaCl reveal +psi (type I) and -psi (type II) CD spectra respectively. From small-angle X-ray scattering studies it could be shown that type I has a long-range order, short-range order supramolecular structure, while type II is of ... |
102628 | The ultrastructural organization of the contractile peripheral protein layer of the human erythroycte membrane. | Erythroycte ghosts fixed in glutaraldehyde were dehydrated in (a) alcohol or acetone, (b) propylene glycol followed by Epon and embedded in an epoxy resin. A water-soluble urea/glutaraldehyde mixture was also used. The aim was to study the structure of the peripheral protein layer, which contains spectrin and actin, in... |
708817 | New electric field methods in chemical relaxation spectrometry. | New stationary relaxation methods for the investigation of ionic and dipolar equilibria are presented. The methods are based on the measurement of non-linearities in conductance and permittivity under high electric field conditions. The chemical contributions to the nonlinear effects are discussed in their static as we... |
702646 | Chemical cross-linking of proteins of Semliki Forest virus: virus particles and plasma membranes from BHK-21 cells treated with colchicine or dibucaine. | Chemical cross-linking of the proteins of Semliki Forest virus has been performed in virus particles and in baby hamster kidney-21 (BHK-21) cells infected with Semliki Forest virus. Most of the studies were done with the reversible cross-linkers dimethyl 3,3'-thiobis(propionimidate) and dithiobis(succinimidyl propionat... |
568145 | Synaptic proteins. Characterization of tubulin and actin and identification of a distinct postsynaptic density polypeptide. | The major proteins in isolated synaptic junctions (SJs) and postsynaptic densities (PSDs) have been compared to actin, tubulin, and the major neurofilament (NF) protein by two-dimensional gel electrophoresis and tryptic peptide map analysis. These studies show: (a) tubulin is present in SJ and PSD fractions and is iden... |
690074 | Stimulation of tetrapyrrole formation in Rhizobium japonicum by restricted aeration. | Cultures of Rhizobium japonicum were grown with vigorous aeration to stationary phase and were then incubated under restricted aeration for several days. Under these "microaerobic" conditions, cellular heme content increased 10-fold, and visible amounts of porphyrins were released into the culture medium. The two predo... |
99427 | Bacillus subtilis spore coats: complexity and purification of a unique polypeptide component. | Extensively washed, dormant spores of Bacillus subtilis were disrupted with glass beads in buffer at pH 7 in the presence of protease inhibitors. Approximately 31% of the total spore protein was soluble, and another 14% was removed from the insoluble fraction by hydrolysis with lysozyme and washing with 1 M KCl and 0.1... |
279906 | Kinetic factors and form determination of the head of bacteriophage T4. | The form of the bacteriophage T4 prehead is described by its icosahedral symmetry, its diameter, and its length. We show how each of these parameters is regulated during prehead formation and ascribe specific form-determining functions to the prehead proteins. The major protein of the head shell can assemble in several... |
29686 | Effects of narcotic analgesics on the uptake and release of 5-hydroxytryptamine in rat synaptosomal preparations. | 1 The effects of various narcotic analgesics on the uptake and release of labelled 5-hydroxytryptamine (5-HT) in brain and spinal cord synaptosomes were investigated.2 Methadone was most active in inhibiting 5-HT uptake (IC(50) 2.5 x 10(-7) M). Levorphanol also inhibited 5-HT uptake to a large extent (IC(50) 8.8 x 10(-... |
279003 | A gene on human chromosome 6 functions in assembly of tissue-specific adenosine deaminase isozymes. | In human tissues, adenosine deaminase (ADA) (adenosine aminohydrolase; EC 3.5.4.4) activity can be separated by gel electrophoresis into several isozymes. A structural gene (ADA) on chromosome 20 codes for the "erythrocyte" isozyme, ADA-1, which is also expressed in some nonerythroid tissues. Nonerythroid cells also di... |
690180 | Freeze-fracture identification of sterol-digitonin complexes in cell and liposome membranes. | To advance our understanding of the organization of cholesterol within cell membranes, we used digitonin in freeze-fracture investigations of model lipid vesicles and tissues. Cholesterol suspensions or multilamellar liposomes composed of phosphatidylcholine with and without cholesterol were exposed to digitonin. Freez... |
687759 | Lecithin bilayers. Density measurement and molecular interactions. | Density measurement are reported for bilayer dispersions of a series of saturated lecithins. For chain lengths with, respectively, 14, 15, 16, 17, and 18 carbons per chain, the values for the volume changes at the main transition are 0.027, 0.031, 0.037, 0.040 and 0.045 ml/g. The main transition temperature extrapolate... |
687601 | Ligand binding sites and subunit interactions of Torpedo californica acetylcholine receptor. | A [3H]bisazido derivative of ethidium bromide was synthesized to identify sites of interaction of ethidium with the acetylcholine receptor from Torpedo californica and to aid in localization of ligand binding sites. For purified solubilized acetylcholine receptor it was shown (a) that the photolabel was competitive wit... |
697725 | Amino acid sequences of alpha-helical segments from S-carbosymethylkerateine-A. Complete sequence of a type-I segment. | The amino acid sequence of a type-I helical segment from the low-sulphur protein (S-carboxymethylkerateine-A) of wool was determined by combining automatic and manual-sequencing data. Whereas in the type-II helical segment most of the cationic groups occur in pairs, 11 of the 22 anionic residues in the sequence of the ... |
673863 | Synthesis, DNA-binding and biological activity of a double intercalating analog of ethidium bromide. | A bis-phenanthridinium salt has been synthesized and its DNA-binding studied. Evidence provided by UV and CD spectra, by thermal denaturation profiles and by equilibrium dialysis of the drug-DNA complex lead to the conclusion that both phenanthridine moieties intercalate in the helix. The double intercalator appears to... |
78958 | A study of proteases and protease-inhibitor complexes in biological fluids. | We have (a) screened a variety of cell lines and body fluids for plasminogen activators and (b) studied the activity of proteases bound to alpha2- macroglobulin after exposing the complexes to partial degradation and/or denaturing procedures to unmask proteolytic activity. The respective results show (a) that the plasm... |
34565990 | The Enthalpy of Formation of MoF<sub>6</sub>(<i>ℓ</i>) by Solution Calorimetry. | Enthalpies of reaction of MoF<sub>6</sub>(<i>ℓ</i>) in NaOH solutions, of MoO<sub>3</sub>(cr) in NaOH solutions, of NaF(cr) in MoO<sub>3</sub>-NaOH solutions, and of NaF(cr) in H<sub>2</sub>O(<i>ℓ</i>) were measured to obtain the enthalpy of reaction of MoF<sub>6</sub>(<i>ℓ</i>) in infinitely dilute NaOH solution: M... |
210248 | Biochemical actions of glucocorticoids on macrophages in culture. Specific inhibition of elastase, collagenase, and plasminogen activator secretion and effects on other metabolic functions. | The effects of glucocorticoids on biochemical functions of macrophages from man, mouse, rabbit, and guinea pig were examined. Secretion of plasminogen activator by human peripheral blood monocytes was decreased by 50% with 1 nM dexamethasone. Differentiation of murine monocytic and granulocytic colonies in agar from bo... |
308086 | Requirement for hexose, unrelated to energy provision, in T-cell-mediated cytolysis at the lethal hit stage. | The requirement for D-glucose in T-cell-mediated cytolysis was studied using mouse spleen cells sensitized against alloantigens in vitro. Glucose was required for cytolysis: (a) cytolysis proceeded in a simple buffered salt solution containing Ca++ and Mg++ (low phosphate-buffered saline, LPBS) in the presence but not ... |
681452 | Mitosis in Barbulanympha. II. Dynamics of a two-stage anaphase, nuclear morphogenesis, and cytokinesis. | Anaphase in Barbulanympha proceeds in two discrete steps. In anaphase-A, chromosomal spindle fibers shorten and chromosomes move to the stationary centrosomes. In anaphase-B, the central spindle elongates and ("telophasic") bouquets of chromosomes, with kinetochores still connected by the shortened chromosomal fibers t... |
78987 | Polyproteins related to the major core protein of mouse mammary tumor virus. | The mouse mammary tumor virus (MuMTV) contains several low-molecular-weight proteins which, together with the genomic RNA, constitute the core structure of the virion. The most abundant protein in the core is the 27,000-dalton protein (p27), and, by analogy to the type C viruses, this protein probably forms the core sh... |
27107 | [The importance of age dependent changes of the organism for therapy (author's transl)]. | Molecular and supramolecular mechanisms of ageing involve biochemical, physiological and morphological alterations of organs. Furthermore physiological disturbances are superimposed by pathological mechanisms of ageing. As a result the number of diseases in higher age increases as well as there are a lot of therapeutic... |
351613 | Cold pepsin digestion: a novel method to produce the Fv fragment from human immunoglobulin M. | A strategy for the proteolytic fragmentation of human IgM has been developed. This method is called "cold pepsin digestion" because of its unique feature of achieving restricted peptic cleavages at 4 degrees and pH 4.0. Cold pepsin digestion has been applied successfully to produce an Fv fragment from 14 human IgM prot... |
208068 | Conformationally restricted bicyclic analogs of somatostatin. | A model for a biologically active conformation of somatostatin is proposed. This model is based primarily on the biological results obtained with novel bicyclic somatostatin analogs having a covalent bridge replacing the side chains of residues 5 and 10, 6 and 11, and 5 and 12, respectively, rather than on physical mea... |
16592533 | Photoprocesses in covalently linked pyrochlorophyllide dimer: Triplet state formation and opening and closing of hydroxylic linkages. | Covalently linked pyrochlorophyllide a dimers exist in solution in either "pinned" or unfolded form, depending on the concentration of hydroxylic (H bonding) or non-H-bonding Lewis bases. Laser flash photolysis studies have been made on these dimer forms and on pyrochlorophyllide monomer at 30-nsec resolution. Spectra ... |
79183 | Mechanism of antigen-induced antibody biosynthesis from antibody precursors, the heavy and light immunoglobulin chains. | The immediate precursors of antibody molecules, the heavy (H) and light (L) peptide chains of the immunoglobulins, combine with each other by means of disulfide bonds formed by dehydrogenation of their cysteine residues. In the absence of an antigen this process yields the heterogeneous mixture of normal immunoglobulin... |
149984 | Two fragments from fibrinolysin digests of ovine prolactin: characterization and recombination to generate full immunoreactivity. | The action of fibrinolysin (plasmin; EC 3.4.21.7) on ovine prolactin has been investigated. It was found that the enzyme selectively cleaves the bond between Met-53 and Ala-54. The two fragments, PRL-(1-53) and PRL-(54-199), have been purified and characterized. A recombinant molecule has been obtained by noncovalent i... |
77912 | Interstrain variation of the major internal structural component (p30gag) of two murine oncornaviruses: comparative immunochemical, biochemical, and biophysical analysis. | The major internal structural protein (p30(gag)) of the Moloney leukemia virus and the endogenous Y-1 murine oncornavirus was examined for biochemical and biophysical manifestations of interstrain antigenic variation. Although the two viral proteins share murine group-specific antigenic determinants, the Y-1 virus p30 ... |
649654 | Electrophorus acetylcholinesterase. Biochemical and electron microscope characterization of low ionic strength aggregates. | The "tailed" molecules of Electrophorus (electric eel) acetylcholinesterase aggregate under conditions of low ionic strength. These aggregates have been studied by sedimentation analysis and high-resolution electron microscopy. They consist of bundles of at least half a dozen molecules, the tails of which are packed si... |
16592524 | Coherent stimulated light emission (lasing) in covalently linked chlorophyll dimers. | The covalently linked chlorophyll a dimer exhibits remarkably different properties in the folded and open configurations. In the folded configuration the absorption maximum is at 695 nm and the fluorescence maximum is at 730 nm. Laser output at 733 and 735 nm is obtained for solutions in wet benzene and 0.1 M ethanol/t... |
77862 | Electron microscope studies of pH effects on assembly of tubulin free of associated proteins. Delineation of substructure by tannic acid staining. | Bovine brain tubulin, purified by phosphocellulose chromatography (PC), was assembled in the presence of 10% dimethyl sulfoxide (DMSO), and the reaction was monitored turbidimetrically. Samples were fixed in glutaraldehyde-tannic acid after completion of polymerization, as indicated by no further change in absorbance, ... |
273900 | Noncovalent interaction of the NH2-terminal fragment of human somatotropin with the COOH-terminal fragment of human choriomammotropin to generate growth-promoting activity. | Complementation of the plasmin fragments of reduced-carbamoylmethylated (Cam) human somatotropin (hGH) with those of reduced-carbamoylmethylated human chorionic somatomammotropin (hCS) have been investigated. It was found that the recombinant obtained by noncovalent interaction of [Cys(Cam)53]hGH-(1-134) with [Cys(Cam)... |
205864 | Species-specific cellular DNA-binding proteins expressed in mouse cells transformed by chemical carcinogens. | Mouse cells transformed by DNA and RNA tumor viruses and by chemical carcinogens have been examined for the presence of specific DNA-binding proteins by DNA-cellulose chromatography. Using mouse DNA-cellulose we have obtained single-stranded DNA-binding proteins from two clones transformed by chemical carcinogens. Simi... |
680949 | The influence of chemotactic factors on neutrophil adhesiveness. | The ability of several chemotactic factors to alter polymorphonuclear neutrophil (PMN) adhesiveness to nylon fibers was studied. Partly purified bacterial chemotactic factor, the isolated chemotactic fragment of human C5, and the chemotactic synthetic tripeptide, formyl-methionyl-leucyl-phenylalanine, transiently enhan... |
655167 | Detection of genetic variation with radioactive ligands. III. genetic polymorphism of transcobalamin II in human plasma. | We detected genetically determined, electrophoretic variants of vitamin B12 binding proteins, most probably transcobalamin II, in human plasma. Polymorphic variants were observed in all populations tested; the two most common alleles (of at least four detected to date) attain frequencies of greater than 40% in Caucasia... |
349564 | Evidence for unaltered structure and in vivo assembly of microtubules in transformed cells. | By using immunoperoxidase cytochemistry at the light and electron microscopic level, microtubles were visualized in a number of "normal" nontumorigenic and transformed tumorigenic cell lines. A well-defined cytoplasmic microtubule complex exists in both normal and transformed interphase cells. The distribution of this ... |
206888 | Fluorescent photoaffinity labeling: adenosine 3',5'-cyclic monophosphate receptor sites. | An approach to the study of protein receptor sites in protein mixtures or supramolecular assemblies by using fluorescence spectroscopy is described. This approach, fluorescent photoaffinity labeling, combines the merits of photoaffinity labeling to attain site-directed reactivity with the probing power of fluorescent l... |
25712 | Purification and some properties of Bacillus macerans cycloamylose (cyclodextrin) glucanotransferase. | Bacillus macerans cycloamylose (cyclodextrin) glucanotransferase (EC 2.4.1.19) was purified by the technique of starch adsorption and DEAE-cellulose column chromatography, and then crystallized from an ammonium sulfate solution containing mM calcium chloride. The crystals of the enzyme were rod-shaped and showed a sing... |
646788 | The binding of porphyrins by ligandin. | Spectrophotometric and equilibrium-dialysis measurements show that ligandin (glutathione S-transferase B, EC 2.5.1.18) binds monomeric porphyrins at a single site with association constants in the range 10(4)-10(6) litre/mol at pH 7.0. Binding affinities are paralleled by the tendencies of the porphyrins to aggregate, ... |
344329 | Intracellular localization of the high molecular weight microtubule accessory protein by indirect immunofluorescence. | Microtubule accessory proteins were isolated from porcine brain microtubules by phosphocellulose chromatography, and the high molecular weight protein (HMW protein), purified from this microtubule-associated fraction by electrophoretic elution from SDS gels, was used to raise antisera in rabbits. In agarose double diff... |
629939 | S-trifluoroacetonyl-coenzyme A:a 19F analogue of acetyl-coenzyme A. | S-Trifluoroacetonyl-coenzyme A has been synthesized in 87% yield by reaction of 1,1,1-trifluoro-3-bromopropanone with trilithium coenzyme A in presence of pyridine. The compound was characterized by its ultraviolet absorption spectrum and 1H and 19F nuclear magnetic resonance spectra. The alpha-methylene protons of the... |
743496 | Nerve trunk excitability and excitability of individual nodes of Ranvier in frog nerve fibers. | It has been found that the duration of the absolute and relative refractory phases at individual nodes of Ranvier in myelinated nerve fibers is longer (by 39 and 33%, respectively) than in the nerve as a whole. In addition, at individual nodes of Ranvier in isolated nerve fibers the phases of facilitation and prolonged... |
647844 | Stereoselectivity and affinity in molecular pharmacology. IV. A search for eudismic-affinity correlations among angiotension II analogues. | In order to establish the applicability of eudismic analysis (correlation between potency and the ratio of isomer potencies), the extensive data reported on the biological activities of angiotensin II analogues were examined. For a series of 13 heptapeptides epimeric at the N-terminal residue, apparent correlations wer... |
644130 | beta-Cyclodextrin as an aid to peritoneal dialysis. Renal toxicity of beta-cyclodextrin in the rat. | A peritoneal dialysate containing beta-cyclodextrin has been shown to accelerate the removal of intravenously administered phenobarbital in rats. It was found that high concentrations of beta-cyclodextrin were toxic to the animals in the single exchange technique employed. The renal toxicity was estimated by measuring ... |
345276 | Interaction of mycobacterial polymethylpolysaccharides with paranaric acid and palmitoyl-coenzyme A: structural specificity and monomeric dissociation constants. | The long-chain polyenoic fatty acids alpha- and beta-paranaric acid form complexes with the 6-O-methylglucose polysaccharide from Mycobacterium smegmatis as demonstrated by an enhanced fluorescence emission of the paranaric acid. This interaction is eliminated by digestion of the methylglucose polysaccharide with alpha... |
273225 | Two regions of the adenovirus 2 genome specify families of late polysomal RNAs containing common sequences. | Late cytoplasmic RNAs specified by two regions of the adenovirus 2 genome (39.3--51.8 and 70.7--83.4 map units) were analyzed by size fractionation of poly(A)-[3H]RNA and subsequent hybridization to DNA fragments. Both regions encode RNAs whose sequence content exceeds the coding capacity of the region. These multiple ... |
273222 | Analysis of the phiX DNA replication cycle by electron microscopy. | We have monitored the development of intracellular phiX DNA forms during the course of a virus life cycle that duplicates as closely as possible the normal infection of individual cells by single virions. The viral DNA was isolated in a one-step purification procedure, and quantitative electron microscopy was performed... |
147464 | Biochemistry of actomyosin-dependent cell motility (a review). | Actins and myosins similar to the major proteins of muscle are the major molecular components of intricate mechanochemical systems that perform numerous vital motility and structural functions in all eukaryotic cells. In this article, after a brief summary of the morphological distribution and ultrastructure of actin, ... |
345243 | Electron microscopic visualization of tRNA genes with ferritin-avidin: biotin labels. | A method is described for indirect electron microscopic visualization and mapping of tRNA and other short transcripts hybridized to DNA. This method depends upon the attachment of the electron-dense protein ferritin to the RNA, the binding being mediated by the remarkably strong association of the egg white protein avi... |
416372 | Juvenile type of generalized ceroid-lipofuscinosis (Spielmeyer-Sjögren syndrome1 II. Biopsy findings. | Rectal biopsies were obtained from 11 children, clinically presumed to suffer from the juvenile type of generalized ceroid-lipofuscinosis. In addition, sural nerve biopsies were performed in 4 cases. Of the various staining procedures applied for light microscopy, Sundan Black B was found to be the most useful, reveali... |
631885 | Virulence of Streptococcus mutans: comparison of the effects of a coupling sugar and sucrose on certain metabolic activities and cariogenicity. | A coupling sugar preparation (sucrose-free [CSSF]), which contains a mixture of sugars, oligosaccharides, and oligosaccharides terminated at the reducing end by sucrose, served as a substrate for growth and acid production by Streptococcus mutans 6715. However, CSSF was a poor substrate for cellular aggregation, glucos... |
564877 | Lipid-free glycerol teichoic acids with potent membrane-binding activity. | Lipid analysis of several glycerol teichoic acid preparations strongly indicated that covalently bound lipid is not required for spontaneous adsorption of glycerol teichoic acid to erythrocyte membranes. Although fatty acids were detected in each of four batches, none were covalently bound. Chloroform-ether-extracted a... |
75240 | Characterization of human high molecular weight kininogen. Procoagulant activity associated with the light chain of kinin-free high molecular weight kininogen. | Human high molecular weight (HMW) kininogen has been isolated and was found to be a single chain protein of approximately equal to 120,000 daltons. Upon digestion with plasma kallikrein bradykinin is generated, and SDS gel electrophoresis of the kinin-free protein reveals an apparent loss in size of 15,000 daltons. The... |
627537 | Protein-lipid-lipopolysaccharide association in the superficial layer of Spirillum serpens cell walls. | The backing layer of the Spirillum serpens VHA cell wall, which supports and is bonded to the outer, structured protein layer, was isolated and shown to be similar in composition to the same elements of the outer membrane. It contained a lipopolysaccharide that was similar, but not identical, to that of the intact wall... |
340808 | Immunofluorescent study of histone H5 in chick erythroid cells from developing embryos and adults. | Indirect immunofluorescence has been used to detect the presence of histone H5 in single cells during avian erythropoiesis. Evidence is presented which demonstrates that this method specifically detects histone H5. The results show that the increase in the amount of H5 which can be extracted from nuclei during erythrop... |
10605456 | Proteins from morphologically differentiated neuroblastoma cells promote tubulin polymerization. | Clonal cells (N18) of the mouse neuroblastoma C-1300 can be induced to undergo a morphological differentiation characterized by the outgrowth of very long neurites (> 150 microns) that contain many microtubules. Because the marked increase in the number and length of microtubules is apparently not due to an increase in... |
256527 | Effects of ions and gravity forces on the supramolecular organization and excitation energy distribution in chloroplast membranes. | This study was designed to explore the possible relationship between chloroplast membrane stacking or particle aggregation in stacked membrane regions (or both) and excitation energy distribution between photosystems I and II. To this end we have quantitatively examined the effects of different concentrations of unival... |
222557 | Structure and function of photoreaction-centre chlorophyll. | Evidence from electron paramagnetic resonance (e.p.r.) studies suggests that the unpaired spin in oxidized P700+. or P865+. is shared by two special chlorophyll a (Chl a) or bacteriochlorophyll a (Bchl a) molecules respectively. Three classes of models have been proposed for special pair reaction centre chlorophyll: as... |
355086 | Protein-lipid interactions and the role of water. | The rigidity of the three-dimensional structure of a native protein is dependent on the network of hydrogen-bonded groups which provide the scaffolding for the other interactions. The structure is stabilized by the hydrophobic interactions of the nonpolar side chains. The latter are formed by the very unfavorable entro... |
246779 | Studies on enzyme models and on the enzyme carboxypeptidase A. | The enzyme carboxypeptidase A has been extensively studied and is thus a good candiate for chemical models and imitation. A model system was constructec which combined two of the three catalytic functional groups of the enzyme together with the appropriate substrate group, and cooperative effective catalysis was demons... |
204588 | Design of a photoaffinity label for the hormone binding site of neurophysin. | The photolabile peptide, L-methionyl-L-tyrosyl-p-azido-L-phenylalaninamide, was synthesized by solution methods. This peptide, as well as the analogous species containing tritiated methionine, were found to bind reversibly and specifically, in the dark, to bovine neurophysin II. The dissociation constant, stoichiometry... |
272656 | Determination of capsid size by satellite bacteriophage P4. | Satellite bacteriophage P4 requires all morphogenic gene products provided by a helper phage, such as coliphage P2, to assemble its own capsid, which is one-third the volume of the larger helper capsid. We have isolated a satellite phage P4 sid (size determination) mutant that is unable to direct the assembly of the sm... |
272655 | Silkmoth chorion proteins: sequence analysis of the products of a multigene family. | Five polypeptide components have been isolated from the eggshell (chorions) of a silkmoth. Two are homogeneous on sodium dodecyl sulfate and isoelectric focusing gels, and three contain predominantly two proteins each. Amino acid analyses show that all five components are similar to each other. These proteins have been... |
343102 | Role of the host in virus assembly: cloning of the Escherichia coli groE gene and identification of its protein product. | Correct assembly of the heads of bacteriophages lambda and T4 requires the function of the groE gene of the Escherichia coli host. We have isolated a transducing derivative of lambda, called lambda gt-Ec.groE, that carries a functional copy of the groE gene. Unlike wild-type lambda, this phage is able to form plaques o... |
73547 | Characterization of the binding of a potent synthetic androgen, methyltrienolone, to human tissues. | The potent synthetic androgen methytrienolone (R 1881), which does not bind to serum proteins, was utilized to characterize binding to receptors in human androgen responsive tissues. Cytosol extracts prepared from hypertrophic prostates (BPH) were utilized as the source of receptor for the initial studies. High affinit... |
757382 | Cutaneous vasculitis. | In this paper the current concepts of cutaneous vasculitis are reviewed, with emphasis on clinical patterns, strict pathologic criteria and mechanisms of injury. A plea is made to classify vasculitis not as syndromes but (a) according to organ involvement (limited cutaneous or complicated multisystem), (b) by cause, (c... |
755685 | Neuronal cells from chick embryo cerebral hemispheres cultivated on polylysine-coated surfaces. | Dissociated cells from 5- to 12-day-old chick embryo cerebral hemispheres were cultivated in polylysine-coated plastic Petri dishes. The polylysine substrate was observed to be favorable for the growth of neuronal cells, whereas glioblast proliferation was inhibited. The optimal conditions for the production of a predo... |
755674 | Behavioral and neuropharmacological toxicology of the macrocyclic ether 18-crown-6. | 18-CROWN-6 was assessed for neurologic effects in rats, mice, and rabbits by intravenous (IV) and intraperitoneal (IP) routes of administration. Male rats and mice exhibited no effects with IV doses to 20 mg/kg. Given IP doses of 20 to 160 mg/kg/day, rats and mice exhibited numerous signs, including aggression, tremors... |
755079 | [Axon-like glial extensions in the pars ventralis of the corpus geniculatum laterale (CGLv) of the albino rat]. | In sections of the Corpus geniculatum laterale, pars ventralis (CGLv) of adult albino rats impregnated according to Golgi-Kopsch, structures are visible very similar to long unbranched axons with large boutons en passage. Within the CGLv these axon-like structures can be followed parallel to the optic tract. Generally ... |
108480 | Role of physiologic autoantibody in the removal of senescent human red cells. | The mechanism by which mononuclear phagocytes distinguish mature "self" from senescent "self" was investigated. Evidence is presented indicating that human mononuclear phagocytes distinguish senescent RBC from mature RBC on the basis of selective Ig attachment to the membranes of senescent cells. This Ig, eluted from s... |
750765 | Membrane alterations in irreversibly sickled cells: hemoglobin--membrane interaction. | Irreversibly sickled cells (ISCs) are sickle erythrocytes which retain bipolar elongated shapes despite reoxygenation and owe their biophysical abnormalities to acquired membrane alterations. Freeze-etched membranes both of ISCs produced in vitro and ISCs isolated in vivo reveal microbodies fixed to the internal (PS) s... |
750764 | Murine leukemia cell hybrids: the quantity of TL antigens expressed by parental and hybrid cells fails to correlate with their sensitivity to TL antibody and complement. | The quantity of thymus-leukemia (TL) antigens expressed by murine leukemia cells is significantly greater than that expressed by somatic hybrids of such cells. Based upon the results of 125I-lactoperoxidase labeling and antibody absorption procedures, and corrected for size differences between the two cell types, the q... |
750763 | Steroid hormone receptor characterization of several histologic variants of a rat prostatic adenocarcinoma. | Several histologic variants of the transplantable R-3327 prostatic adenocarcinoma carried in male Copenhagen rats have been characterized and the histologic types have been correlated with steroid hormone receptor content. One type is clearly an adenocarcinoma; this tumor is hormonally responsive and contains substanti... |
220467 | Gap junctions and ACTH sensitivity in Y-1 adrenal tumor cells. | Initial studies of adrenocorticotropin-sensitivity (ACTH-sensitive) and ACTH-insensitive Y-1 adrenal cortical tumor cell lines suggest a relationship between responsiveness to ACTH and the presence of gap junctions. An ACTH-sensitive clone of Y-1 cells possesses gap junctions and these junctions appear to enlarge with ... |
750762 | Increase in the affinity of the uridine phosphorylation system for ATP after serum or insulin activation of 3T3 fibroblasts. | The stimulation of uridine uptake, brought about by the addition of serum or insulin to quiescent 3T3 fibroblasts, is associated in the half-saturation concentration of the uridine phosphorylating system for the substrate ATP, with relatively little change in the maximum uptake or in the affinity for uridine. In stimul... |
750761 | Intracellular compartmentation and transport of metabolites. | The intracellular locations of enzymes and metabolites were determined for ornithine metabolism in Neurospora. Pulse label experiments were used to measure the rates of intracellular translocations and the sizes of compartmented pools of metabolites in the mitochondrial, cytosolic and vesicular compartments. The result... |
108479 | Effects of divalent-cation chelators and chloramphenicol on the spatial relationship of the nuclear envelope to chromatin in micronuclei of Chinese hamster cells. | In the presence of the spindle poison Colcemid in the culture medium to prevent anaphase, approximately 20% of Chinese hamster metaphase cell were converted to micronucleated cells during 7 h. In the micronuclei the chromosome had become enclosed by a nuclear envelope (NE). In the light-microscope the micronuclei were ... |
748684 | Bilayer balance and regulation of red cell shape changes. | Discocytic human red cells undergo discocyte-echinocyte and discocyte-stomatocyte transformations under the action of a wide variety of lipid-soluble anionic and cationic agents respectively. These shape transformations are explained by the bilayer couple hypothesis of Sheetz and Singer to be the result of preferential... |
219299 | Redistribution of intramembrane particles of human erythrocytes induced by HVJ (Sendai virus): a prerequisite for the virus-induced cell fusion. | Aggregation of intramembrane particles of human erythrocytes was found to be induced by HVJ (Sendai virus) under conditions which lead to cell fusion. Degree of polyerythrocyte formation was compared under a variety of conditions with extent of cluster formation observed with the same preparations. Both structural chan... |
34754 | Formation of gamma-glutamyl-epsilon-lysine bridges between membrane proteins by a Ca2+-regulated enzyme in intact erythrocytes. | A rise in the intracellular concentration of Ca2+-ions in human erythrocytes causes the formation of high-molecular-weight membrane protein polymers, cross-linked by gamma-glutamyl-epsilon-lysine side chain bridges. Cross-linking involves proteins at the cytoplasmic side of the membrane (band 4.1, spectrin, and band 3 ... |
85807 | Inhibition by protease inhibitors of binding of adrenal and sex steroid hormones. | Binding of steroid hormones is inhibited by protease inhibitors and substrates. The protease inhibitors phenylmethyl sulphonylfluoride, tosyl-lysine chloromethyl ketone, and tosylamide-phenylethyl-chloromethyl ketone and the protease substrates tosyl arginine methyl ester and tryptophan methyl ester eliminate specific ... |
571032 | The spontaneous release of a high-molecular-weight aggregate containing immunoglobulin G from the surface of Ehrlich ascites tumor cells. | The spontaneous release of tumor cell antigens from the cell surface into the circulation has been proposed as a mechanism whereby tumors may escape the immune response of the host. In this study we have found that Ehrlich ascites tumor cells after removal from the host (mouse) spontaneously release significant amounts... |
219298 | Photolabile and paramagnetic reagents for the investigation of transmembrane signaling events. | To investigate the dynamics of membrane processes that may be integral components of specific transmembrane signaling events we have synthesized several novel paramagnetic probes and their photoreactive counterparts. The structure of these probes was designed to (1) restrict "flipping" across the membrane bilayer; (2) ... |
748683 | Effects of PTH and Ca2+ on renal adenyl cyclase. | The effects of calcium ion on the adenylate cyclase system was studied in isolated, renal basal-lateral plasma membranes of the rat. Bovine parathyroid hormone (bPTH) and a guanyl triphosphate analogue, Gpp(NH)p were used to stimulate cyclase activity. Under conditions of maximal stimulation, calcium ions inhibited cyc... |
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