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3514462 | Flow cytometric analysis of the effects exerted by monoclonal antibodies on binding and uptake of Leishmania mexicana subsp. mexicana promastigotes by murine peritoneal macrophages. | A flow cytometric assay was developed to quantitate the binding kinetics of Leishmania mexicana subsp. mexicana promastigotes to murine peritoneal macrophages and to determine if selected membrane-specific monoclonal antibodies would exert an effect on the binding process. A total of three monoclonal antibodies, all re... |
3485524 | Labelling of chlorophylls and precursors by [2-14C]glycine and 2-[1-14C]oxoglutarate in Rhodopseudomonas spheroides and Zea mays. Resolution of the C5 and Shemin pathways of 5-aminolaevulinate biosynthesis by thin-layer radiochromatography. | The C-5 of 5-aminolaevulinate, a tetrapyrrole precursor which accumulates when inhibitory laevulinate is present, is derived from either the C-2 of glycine by the 5-aminolaevulinate-synthase-mediated Shemin pathway or the C-1 of 2-oxoglutarate by the C5 pathway. Thin-layer-radiochromatographic procedures are described ... |
2419473 | Expression and function of a nonglycosylated major histocompatibility class I antigen. | The major histocompatibility class I antigens, expressed in most somatic cells, have carbohydrate moieties. We constructed mutant mouse MHC class I genes in which codons for the N-linked glycosylation sites were replaced by those of other amino acids. L cell transformants expressing the nonglycosylated class I antigens... |
3022127 | Absence of a structural basis for intracellular recognition and differential localization of nuclear and plasma membrane-associated forms of simian virus 40 large tumor antigen. | The simian virus 40 large tumor antigen (T-ag) is found in both the nuclei (nT-ag) and plasma membranes (mT-ag) of simian virus 40-infected or -transformed cells. It is not known how newly synthesized T-ag molecules are recognized, sorted, and transported to their ultimate subcellular destinations. One possibility is t... |
3487315 | T-cell recognition of human haemoglobin. Localization of the full T-cell recognition profile of the beta-chain by a comprehensive synthetic strategy. | This paper reports the localization of the regions on the beta-chain that are recognized by T cells from mice immunized with haemoglobin. The 14 overlapping peptides encompassing the entire beta-chain were examined in vitro for their ability to stimulate lymph-node cells from haemoglobin-primed B10.D2 (H-2d) and SJL (H... |
2424430 | Antigenic structure of human haemoglobin. Localization of the antigenic sites of the beta-chain in three host species by synthetic overlapping peptides representing the entire chain. | A comprehensive synthetic approach is applied here to localize the continuous antigenic sites of the beta-chain of haemoglobin. The approach was based on the synthesis and purification of the following consecutive 15-residue peptides (each overlapping by five residues at both ends with the peptides preceding it and fol... |
3521485 | Novobiocin antagonism of amastigotes of Trypanosoma cruzi growing in cell-free medium. | Inhibitors of the enzyme bacterial topoisomerase II (DNA gyrase) were evaluated for activity against Trypanosoma cruzi (Brazil strain), based on the theoretical need for a topoisomerase II in the replication of the kinetoplast DNA network. Novobiocin (500 micrograms/ml) antagonized amastigotes of T. cruzi growing in a ... |
3716791 | Fatal hepatic necrosis after shock. | A clinicopathological study was undertaken in 15 cases of massive hepatic necrosis after shock. The GOT and GPT level exceeded 1000 units in 10 cases. The 15 cases consisted of 3 diagnosed as fulminant hepatitis clinically and 12 diagnosed as disseminated intravascular coagulation (DIC) or multiple systemic organ failu... |
3709520 | The major surface protein of Leishmania promastigotes is anchored in the membrane by a myristic acid-labeled phospholipid. | Promastigotes of the protozoan parasite Leishmania major were biosynthetically labeled with myristic acid. Solubilization and phase separation in the non-ionic detergent Triton X-114 shows that the label is not incorporated into soluble hydrophilic proteins, but is incorporated into a few insoluble proteins. The bulk o... |
3709444 | Roles of metallothionein and related proteins in metal metabolism and toxicity: problems and perspectives. | This summary examines some of the known and hypothesized roles of metallothionein and related proteins in mediating the metal metabolism and toxicity from a chemical perspective. It attempts to examine in kinetic terms how such molecules may exert homeostatic control over the intracellular bioavailability of metal ions... |
2423098 | Separation and characterization of four different amylases of Entamoeba histolytica. II. Characterization of amylases. | Purified E. histolytica amylases III to VI were characterized by their hydrolytic behaviour towards 4-nitrophenyl alpha-malto-oligosaccharides, malto-oligosaccharides, amylose, amylopectin, glycogen and Y-cyclodextrin. The influence of specific inhibitors on the amylase activity of E. histolytica was examined and compa... |
2939646 | Activation of streptolysin S in vitro by oligonucleotides. | When washed streptococci were incubated in a phosphate buffer containing MgSO4 and maltose (Bernheimer's basal medium) and centrifuged, no hemolytic activity was detected in the supernatant. Although incubation of the spent medium with carrier oligonucleotide did not yield active hemolysin, the mixture turned to be sig... |
3699545 | Is there a biochemical basis for lower oesophageal sphincter (LOS) resting pressure? | Myosin plays a fundamental role in the contraction of muscle cells. Some structural differences of this protein are related to the different physical properties of muscle--that is, speed of shortening. The typical myosin protein has a molecular weight of 460 000 daltons and is made up of six subunits: two heavy chains ... |
2870898 | Metabolism of unsaturated derivatives of valproic acid in rat liver microsomes and destruction of cytochrome P-450. | 2-n-Propyl-4-pentenoic acid (delta 4-VPA), an unsaturated metabolite of valproic acid (VPA), and the ethyl ester of delta 4-VPA were tested for their ability to cause NADPH- and time-dependent loss of cytochrome P-450 in hepatic microsomal preparations from phenobarbital-pretreated rats. Ethyl delta 4-VPA gave a large ... |
3697472 | Polymorphic phase behavior of platelet-activating factor. | Vibrational Raman and 31P NMR spectroscopic experiments have been performed as a function of temperature on aqueous dispersions of 1-0-octadecyl-2-acetoyl-sn-glycero-3-phosphocholine, a chemically synthesized platelet-activating factor. In the temperature range of -7 to 30 degrees C, the C(18)/PAF-H2O system is shown, ... |
3456591 | Bryostatin, an activator of the calcium phospholipid-dependent protein kinase, blocks phorbol ester-induced differentiation of human promyelocytic leukemia cells HL-60. | Phorbol esters bind to and activate a calcium phospholipid-dependent protein kinase (C kinase). Some researchers believe that activation of C kinase is necessary for the induction of phorbol ester biologic effects. Our research indicates that bryostatin, a macrocyclic lactone that binds to the phorbol ester receptor in... |
3456590 | Metastable photoproducts from carbon monoxide myoglobin. | The photoproduct of carbon monoxide myoglobin generated at 4 K and lower has a resonance Raman spectrum characteristic of a high-spin heme but in which the high-frequency core size-sensitive lines are at lower frequency than those in the deoxy preparation. Such differences are not detected in the photoproduct generated... |
3005339 | Nerve-induced remodeling of muscle basal lamina during synaptogenesis. | To identify mechanisms that regulate the deposition of the junctional basal lamina during synaptogenesis, immunocytochemical experiments were carried out on cultured nerve and muscle cells derived from Xenopus laevis embryos. In some experiments successive observations were made on individual muscle cells after pulse-l... |
2936752 | Evidence for a polarity in the distribution of proteins from the cytoskeleton in Torpedo marmorata electrocytes. | The subcellular distribution of the 43,000-D protein (43 kD or v1) and of some major cytoskeletal proteins was investigated in Torpedo marmorata electrocytes by immunocytochemical methods (immunofluorescence and immunogold at the electron microscope level) on frozen-fixed sections and homogenates of electric tissue. A ... |
2419310 | Cloning and characterization of the beta-amylase gene from Bacillus polymyxa. | The gene for beta-amylase was isolated from Bacillus polymyxa by molecular cloning in B. subtilis. B. subtilis cells containing this gene express and secrete an amylase which resembles the B. polymyxa beta-amylase and barley beta-amylase in terms of the products it generates during carbohydrate hydrolysis. Starch hydro... |
3512520 | Properties of an ordered ring structure formed by recombinant Treponema pallidum surface antigen 4D. | Ultrastructural and biochemical studies of a recombinant Treponema pallidum surface antigen designated 4D have been conducted due to its likely biological significance. Electron microscopy demonstrated that the 190-kilodalton (kDa) 4D molecule is an ordered ring structure of 10-nm diameter. The 90-kDa proteinase K-trea... |
3512306 | Effect of the integrity of the myofibrillar structure on the tryptic accessibility of a hinge region of the myosin rod. | Limited proteolysis has been used to study the influence of actin, in the absence or presence of regulatory proteins of the thin filament (tropomyosin and troponin), as well as that of the myofibrillar structure on the tryptic cleavage of the heavy meromyosin (HMM)/light meromyosin (LMM) hinge region in myosin heavy ch... |
2855797 | Expression of ACTH-induced corticosteroid biosynthesis in newborn rat adrenocortical cells cultured in serum-free and carrier protein-free medium containing a cholesterol-alpha-cyclodextrin complex. | Newborn rat adrenocortical cells were successfully cultured in a serum-free carrier protein-free medium (SPFM) by using alpha-cyclodextrin as a cholesterol carrier and have expressed corticosteroid biosynthesis in this medium. A stable inclusion complex of cholesterol-alpha-cyclodextrin with a molar ratio of almost 1 w... |
2431270 | Three tightly linked genes encoding human type I keratins: conservation of sequence in the 5'-untranslated leader and 5'-upstream regions of coexpressed keratin genes. | We have isolated and subcloned three separate segments of human DNA which share strong sequence homology with a previously sequenced gene encoding a type I keratin, K14 (50 kilodaltons). Restriction endonuclease mapping has demonstrated that these three genes are tightly linked chromosomally, whereas the K14 gene appea... |
2423326 | Modelling of the combining sites of three anti-lysozyme monoclonal antibodies and of the complex between one of the antibodies and its epitope. | Models of the antigen combining sites of three monoclonal antibodies, which recognise different but overlapping epitopes within the 'loop' region of hen egg lysozyme (HEL), have been generated from the cDNA sequences of their Fv regions (the VL and VH domains) and the known crystal structures of immunoglobulin fragment... |
3697836 | Attenuation of the responses to repeated cholinergic interventions in the isolated dog atrium. | In the isolated, blood-perfused canine right atrium, which was pretreated with propranolol, negative chronotropic and inotropic responses were evoked by stimulation of the intramural parasympathetic nerve fibers or by intra-arterial infusion of acetylcholine (ACh). Successive cholinergic interventions were applied; fir... |
3486001 | Biosynthesis of porphyrins and corrins. 1. 1H and 13C NMR spectra of (hydroxymethyl)bilane and uroporphyrinogens I and III. | High-field NMR spectroscopic methods have been applied to study the reactions catalyzed by porphobilinogen (PBG) deaminase and uroporphyrinogen III (uro'gen III) cosynthase, which are the enzymes responsible for the formation of the porphyrin macrocycle. The action of these enzymes in the conversion of PBG, [2,11-13C]P... |
3514904 | An immunofluorescent study of the microtubule organization in Trichomonas vaginalis using antitubulin antibodies. | The flagellated protozoon Trichomonas vaginalis, parasite of the human urogenital tract, possesses a well developed microtubule system organized in highly differentiated structures. We have shown by immunoblotting that monospecific anti-sheep brain tubulin antibodies are able to react with the microtubular tubulin of T... |
3958926 | Hydrophilic cyclodextrin derivatives enable effective oral administration of steroidal hormones. | Condensation products of beta-cyclodextrin with propylene oxide or epichlorohydrin, which are amorphous and thus very soluble in water, were used to form complexes with testosterone, progesterone, and estradiol. Sublingual/buccal administration of tablets of these complexes led to effective absorption and entry of the ... |
2420383 | Equilibrium binding constants for Tl+ with gramicidins A, B and C in a lysophosphatidylcholine environment determined by 205Tl nuclear magnetic resonance spectroscopy. | Nuclear Magnetic Resonance (NMR) 205Tl spectroscopy has been used to monitor the binding of Tl+ to gramicidins A, B, and C packaged in aqueous dispersions of lysophosphatidylcholine. For 5 mM gramicidin dimer in the presence of 100 mM lysophosphatidylcholine, only approximately 50% or less of the gramicidin appears to ... |
3006033 | Bacteriophage T4 DNA topoisomerase mediates illegitimate recombination in vitro. | We have found that purified T4 DNA topoisomerase promotes recombination between two phage lambda DNA molecules in an in vitro system. In this cross, T4 DNA topoisomerase alone is able to catalyze the recombination and produce a linear monomer recombinant DNA that can be packaged in vitro. ATP is not required for this r... |
3456569 | Theoretical calculation of relative binding affinity in host-guest systems. | The relative free energy of binding the anions Cl- and Br- to the macrotricyclic receptor SC24 in water has been computed by a computer simulation technique. This result and an incidental result for the relative free energy of hydration of the anions are in excellent agreement with experimental data. The simulation app... |
2937018 | Effect of SSB protein on cleavage of single-stranded DNA by phi X gene A protein and A* protein. | Gene A protein of bacteriophage phi X174 plays a role as a site-specific endonuclease in the initiation and termination of phi X rolling circle DNA replication. To clarify the sequence requirements of this protein we have studied the cleavage of single-stranded restriction fragments from phi X and G4 viral DNAs using p... |
3456171 | Study of an octadecaneuropeptide derived from diazepam binding inhibitor (DBI): biological activity and presence in rat brain. | An endogenous brain neuropeptide with 104 amino acid residues that modulates gamma-aminobutyric acid receptor function was termed DBI because it displaces diazepam from its specific brain binding sites. Tryptic digestion of DBI generates an octadecaneuropeptide (ODN) that is more potent than the parent compound in the ... |
3003386 | Properties of the simian virus 40 (SV40) large T antigens encoded by SV40 mutants with deletions in gene A. | The biochemical properties of the large T antigens encoded by simian virus 40 (SV40) mutants with deletions at DdeI sites in the SV40 A gene were determined. Mutant large T antigens containing only the first 138 to 140 amino acids were unable to bind to the SV40 origin of DNA replication as were large T antigens contai... |
3511095 | Control of heme metabolism with synthetic metalloporphyrins. | Studies with synthetic metal-porphyrin complexes in which the central iron atom of heme is replaced by other elements indicate that those heme analogues that cannot be enzymatically degraded to bile pigments possess novel biological properties that may have considerable clinical as well as experimental value. Such stud... |
3944134 | The structural bases for the unique ligand binding properties of Glycera dibranchiata hemoglobins. A resonance Raman study. | The hemoglobin of the marine annelid Glycera dibranchiata possesses several unique features: the hemoglobin consists of multiple monomeric and polymeric components, quaternary structure is lacking, the distal histidine is replaced by leucine in at least one monomeric constituent, and 4) the protein exhibits extremely r... |
3510983 | Environmental modulation of lipopolysaccharide chain length alters the sensitivity of Escherichia coli to the neutrophil bactericidal/permeability-increasing protein. | We have shown previously that the sensitivity of Escherichia coli to the neutrophil bactericidal/permeability-increasing protein (BPI) depends mainly on the polysaccharide chain length of outer membrane lipopolysaccharides (LPS) (J. Weiss, S. Beckerdite-Quagliata, and P. Elsbach, J. Clin. Invest. 65:619-628, 1980). Thu... |
3610990 | Wever and Lawrence revisited: effects of nulling basilar membrane movement on concomitant whole-nerve action potential. | It has been assumed for decades that mechanically stimulating hair cells, both inner and outer (IHC, OHC), leads to CM and subsequent neural activity. A test of that assumption was attempted in this experiment. Tone-pips of 300 msec duration at 4 or 5 kc/s with fast rise times were simultaneously presented to the cochl... |
2951300 | Cyclodextrin-glycosyltransferase from Klebsiella pneumoniae M5a1: cloning, nucleotide sequence and expression. | The structural gene encoding cyclodextrin-glycosyltransferase of Klebsiella pneumoniae strain M5a1 was cloned; it is expressed both in Escherichia coli and in K. pneumoniae and the gene product is secreted into the extracellular space. Determination of the nucleotide sequence revealed an open reading frame coding for a... |
3816509 | A comparison of the effect of Lipo PGE1 and other related compounds on experimental peripheral arterial occlusive disease in rats. | The effect of Lipo PGE1 (prostaglandin E1 incorporated in lipid microspheres) on laurate-induced peripheral arterial occlusive disease in rats was evaluated and compared with that of other related compounds. Lipo PGE1 showed a potent inhibitory effect on the progression of lesions in this model, but Lipo PGA1 had no su... |
3792141 | Calcium and the regulation of cytoskeletal assembly, structure and contractility. | Calcium plays a central role in the regulation of cytoskeletal assembly, structure and contractility. In the case of actin there are a number of functional classes of actin-binding proteins which confer on a given actin filament its specific function in the cell. Among these various classes of actin-binding proteins ar... |
3788367 | Structure of thick filaments from insect flight muscle. | The supramolecular organization of thick (myosin) filaments isolated from insect flight muscle was studied using negative staining and shadowing techniques. The electron microscopical findings favour the two-stranded arrangement of double cross-bridges rather than a four- or six-stranded structures of single cross-brid... |
3024198 | The possible modulation of morphine analgesia by the supramolecular GABA receptor complex. | In the present study, the mechanism of the antagonistic action of 0.5 mg/kg diazepam on the analgesic effect of morphine was investigated. While Ro 15-1788, a benzodiazepine receptor antagonist, was found to partially reverse the inhibitory action of diazepam on morphine analgesia, a chloride channel blocking agent, pi... |
3782260 | Inhibition of experimental pulmonary metastasis in mice by beta-cyclodextrin-benzaldehyde. | The effect of beta-cyclodextrin-benzaldehyde (CDBA) on experimental pulmonary metastasis in C3H/He mice was examined. In an in vitro assay, the growth of RCT(+) cells was inhibited by 1200 micrograms/ml CDBA using unrenewed media, and by 600 micrograms/ml CDBA in that using daily renewed media. When mice were treated d... |
3095768 | Physicochemical hair conformation of patients with Sanfilippo disease type IIIA. | Sanfilippo disease type IIIA is an inborn error of metabolism with a deficiency in the heparan sulfamidase. Besides severe psychomotor retardation hair changes are obligatory. Hair is found to be coarse like a brush. We applied X-ray diffraction and infrared spectroscopy to characterize the conformation of hair samples... |
3760319 | A retrospective study of 130 consecutive multiple trauma patients in an intensive care unit. | A retrospective study of 130 multiple trauma patients admitted to an intensive care unit is presented. Overall mortality was 33% for a mean ISS of 39.4. Craniocerebral trauma, multiple organ failure, sepsis and ARDS are the main causes of death, although there is no statistical difference for these between survivors an... |
3743368 | Mechanism of interstrand cross-linking of DNA by anticancer 2-haloethylnitrosoureas. | E and Z-2-haloethyldiazotates, which have been postulated as the ultimate electrophiles responsible for the biological activity of 2-haloethylnitrosoureas (HENUs), have been synthesized and characterized by 15N-nmr. Their stability and solubility in organic solvents are increased by forming crown ether complexes. While... |
3701868 | Self-association of haemoglobin Olympia (alpha 2 beta 2 20 (B2) Val----Met). A human haemoglobin bearing a substitution at the surface of the molecule. | Oxygenation measurements at equilibrium were carried out for solutions of pure haemoglobin (Hb) Olympia (alpha 2 beta 2 20 (B2) Val----Met) at 200 microM (haem) and revealed a high oxygen affinity (P50 = 4.2 torr at pH 7.20, 25 degrees C) compared to HbA (P50 = 5.6 torr), with the Hill coefficient (eta H) reduced from ... |
3700607 | Relationships between alternative complement pathway activation, C-reactive protein, and pneumococcal infection. | In the absence of specific antibody, opsonization of Streptococcus pneumoniae may be mediated by the alternative complement pathway (AP) or by C-reactive protein (CRP) via C1 binding. To determine the role of these mechanisms in pneumococcal (PNC) disease, we studied 19 patients with differing severities of PNC infecti... |
2422198 | Immunoblot analyses of Candida albicans-associated antigens and antibodies in human sera. | We tested 10 patient sera for the presence of immunoglobulin G (IgG) antibodies to Candida albicans and for C. albicans antigens by immunoblot analysis (i.e., electrotransfer blot radioimmunoassay) (G. E. Smith and M. D. Summers, J. Virol. 39:125-137, 1981). We evaluated sera from two patients at risk for candidiasis, ... |
3700601 | High-performance liquid chromatography of mycolic acids as a tool in the identification of Corynebacterium, Nocardia, Rhodococcus, and Mycobacterium species. | High-performance liquid chromatography of bromophenacyl esters of mycolic acid was used as an aid to assign a particular organism to one of four mycolic acid-containing genera. A gradient elution system, with methanol and chloroform, was used to distinguish representative mycolic acid patterns for the genera Corynebact... |
3515005 | Effect of a prostaglandin E1 derivative (OP-1206) and acetylsalicylic acid on electrically induced thrombosis in guinea-pig mesenteric artery and its modification by an inhibitor of prostaglandin I2 synthetase, tranylcypromine. | The antithrombotic effect of a prostaglandin E1 derivative, OP-1206 (17S-20-dimethyl-trans-delta 2-PGE1) X alpha-cyclodextrin clathrate (OP-1206 X alpha-CD), was compared with that of acetylsalicylic acid (ASA) in a electrically induced thrombosis model of guinea-pig mesenteric arteries using intact animals and animals... |
3514123 | Proteolytic processing and compartmentalization of the primary translation products of mammalian apolipoprotein mRNAs. | The steps involved in the initial assembly of apolipoproteins and lipids into supramolecular arrays (nascent lipoprotein particles) are largely unknown. Examination of the proteolytic processing and compartmentalization of the primary translation products of apolipoprotein mRNAs represents one approach to deciphering t... |
3485450 | Macromolecular assemblies of myosin. | The self-assembly of myosin into filamentous structures is a highly cooperative and rapid process. Nevertheless, the presence of nonequivalent bonding interactions within the filament permits differential stabilization of several macromolecular assemblies of myosin under well-controlled ionic conditions in citrate/Tris... |
3955169 | Principles in the assembly of annelid erythrocruorins. | Erythrocruorins are giant extracellular respiratory proteins found freely dissolved in the blood of annelids. We present here results from our ultracentrifugation, electron microscopy, spectroscopy, and diffraction experiments on these erythrocruorins. These data are rationalized in terms of a three-dimensional model o... |
3955167 | Resolving pathways of functional coupling within protein assemblies by site-specific structural perturbation. | Site-specific structural modification is a powerful tool for studying functional mechanisms in proteins where the structures may be manipulated by direct chemical modification, by selection of naturally-occurring mutants, or by site-directed mutagenesis. Here, we present a general strategy for such studies, which we te... |
3006755 | Monomers, dimers, and minifilaments of vertebrate skeletal myosin in the presence of sodium pyrophosphate. | The self-assembly of myosin in the presence of sodium pyrophosphate was studied in the pH range between 7.0 and 8.5. As evidenced by sedimentation velocity (S0(20,w) = 6.30 S) and light-scattering measurements (molecular weight of 470 000; radius of gyration = 45 nm), myosin existed in a predominantly monomeric form in... |
2936949 | [Supramolecular organization of glycolytic enzymes]. | On the basis of the analysis of the data on adsorption of glycolytic enzymes to structural proteins of skeletal muscle and to erythrocyte membranes, the data on enzyme-enzyme interactions and the data on the regulation of activity of glycolytic enzymes by cellular metabolites the structure of glycolytic enzyme complex ... |
3512975 | [Symmetry of multienzyme complexes]. | A model for studying the symmetry of stable states arising from polyenzymic complex conformations is proposed. A formal scheme of submolecular structure self-assembly, on which the model is based, enables it not only to limit the class of conformations but in some cases to determine the structure of a complex in an una... |
3951436 | [Accessibility of porphyrin macrocycle in myoglobin at various pH levels. Fluorescence study of the porphyrin-globin complex]. | The fluorescent properties of the complexes of apoMb-PPIX and dimethyl-PPIX were studied in a wide range of pH and ionic strength. The quenching of fluorescence of PPIX in the complex by I- is shown to be of dynamic type Increasing of the Stern--Volmer constant was observed in the acidic region of pH. From the sections... |
3948755 | [Changes in the supramolecular structure of chromatin and pepsinogen synthesis in the gastric mucosa of rats undergoing N-methyl-N'-nitro-N-nitrosoguanidine-induced carcinogenesis]. | A model of gastric tumour induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in rats made it possible to detect essential alterations of chromatin-DNA-protein complexes, that is a weakening of the DNA-protein linkage. The changes appear at early stages of carcinogenesis and persist in induced adenocarcinomas of the... |
3002517 | [Interaction of piracetam with 3H-imipramine binding sites and the GAMA-benzodiazepine receptor complex of brain membranes]. | Piracetam at a concentration of 10(-6) M was shown to behave as a noncompetitive inhibitor of 3H-imipramine specific binding to rat brain membranes. At the same time piracetam failed to influence specific binding of 3H-mianserin to membranes of guinea-pig cerebellum, which is indicative of its inability to suppress his... |
3942034 | Novel dimeric configurations from bacteriophage G4 replicative form DNA. | The oligomeric fraction of the replicative form of phage G4 was prepared by sedimentation on three successive CsCl velocity gradients followed by resolution on CsCl-propidium diiodide equilibrium gradients and subfractions through the equilibrium gradients were examined by electron microscopy. The most frequent dimer s... |
2417234 | Functional channel formation associated with cytotoxic T-cell granules. | Lymphocyte granules from cytotoxic T-lymphocyte lines A2, A11, and R8 were enriched by subcellular fractionation using a Percoll gradient. Granule-enriched fractions showed potent hemolytic activity in the presence of Ca2+. Isolated granules induced rapid Ca2+-dependent membrane depolarization of J774 macrophage-like c... |
3941750 | Parathyroid hormone effect on the fragility of human young and old red blood cells in uremia. | Parathyroid hormone (PTH) is elevated in patients with chronic renal failure (CRF) and was suggested to be one of the factors responsible for the anemic syndrome of these patients because it raises the osmotic fragility of the red blood cells (RBC). In the present study, the youngest and oldest RBC were separated from ... |
3753614 | Molecular mimicry: frequency of reactivity of monoclonal antiviral antibodies with normal tissues. | More than 600 monoclonal antiviral antibodies made against 11 different viruses were screened against 14 different organs from normal uninfected mice. Of these antiviral antibodies, 21, or approximately 3.5%, reacted with specific cells in these organs. Several of these antibodies were of the multiple-organ-reactive ty... |
3001350 | Toward an in vitro system for picornavirus assembly: purification of mengovirus 14S capsid precursor particles. | Mengovirus 14S subviral protein particles generated in infected L cells and in a cell-free translation system primed with mengovirus RNA were purified by sucrose gradient centrifugation and immunoaffinity chromatography. The preparations from both sources contained essentially pure proteins epsilon, alpha, and gamma, a... |
3455706 | Fluorescent opsonization assay: binding of plasma fibronectin to fibrin-derivatized fluorescent particles does not enhance their uptake by macrophages. | A simple method for assessing the opsonic properties of plasma fibronectin is described. The method is based on the uptake of protein-derivatized fluorescent particles by mouse peritoneal macrophages. With this system, fibronectin stimulated the uptake of gelatin conjugated to carboxylated fluorescent particles. In con... |
3510264 | Relation of structure to function for the U. S. reference standard endotoxin after exposure to 60Co radiation. | The structure and function of the highly purified U.S. reference standard endotoxin (RSE) were studied after exposure to ionizing radiation from a 60Co source. With increasing doses of radiation, the trilaminar ribbon-like structure of untreated endotoxin exhibited focal swelling, after which only spherical particles w... |
3079769 | The pupal cuticle of Drosophila: differential ultrastructural immunolocalization of cuticle proteins. | Precise ultrastructural localization of Drosophila melanogaster pupal cuticle proteins (PCPs) was achieved by the immunogold labeling of frozen thin sections. PCPs were found in lamellate cuticle and intracellular vesicles but, curiously, were absent from the assembly zone of the cuticle. Antibodies that distinguish be... |
3079734 | Production of listeriolysin by beta-hemolytic strains of Listeria monocytogenes. | Listeriolysin was isolated from target rabbit erythrocyte membranes after lysis of the cells with partially purified toxin derived from a culture supernatant of Listeria ivanovii. The membrane form of the toxin exhibited properties similar to those previously found for streptolysin O. Detergent-solubilized, delipidated... |
24435362 | Organization of the photosynthetic units, and onset of electron transport and excitation energy distribution in greening leaves. | The development and organization of the Photosynthetic units follow a step-wise assembly process. First the core complexes of the PSI and PSII units are formed, followed by their light-harvesting components; then an assembly process of these components into supramolecular structures takes place. Parallel to this, the c... |
3479952 | Relationship between mouth-opening force and facial skeletal dimensions in human females. | Maximum (MOF) and average (AOF) isometric mouth-opening forces were measured with an extra-oral gnathodynamometer in 34 females. Mean MOF and AOF with the teeth in centric relation were respectively 99.6 +/- 22.2 and 89.0 +/- 19.4 N with significant relationships between both MOF and AOF and body mass. Analysis of ceph... |
3442774 | New approaches to synthetic receptors. Studies on the synthesis and properties of macrocyclic C-glycosyl compounds as chiral, water-soluble cyclophanes. | In an approach for the preparation of macrocyclic C-glycosyl compounds, the C-glycosyl residue is synthesized by acid-assisted reduction of a cyclic hemiacetal with sodium cyanoborohydride. Macrocycle formation is effected by the reaction of a symmetrical bis(C-glycosyl)derived diamine with a dicarboxylic acid dichlori... |
3442657 | Resonance Raman studies of acetylheme-reconstituted myoglobins. Characterization of 2- versus 4-substituent/protein interactions. | Resonance Raman (RR) spectra are reported for the deoxy, oxy, and metcyano species of sperm whale myoglobin (Mb) reconstituted with deuteroheme, 2-acetyldeuteroheme, 4-acetyldeuteroheme, and 2,4-diacetyldeuteroheme. The functional inequivalence of the 2- and 4-positions of the heme moiety is manifested in the vibration... |
3442320 | Separation of optical isomers of scopolamine, cocaine, homatropine, and atropine. | Different drug stereoisomers can have different physiological and therapeutic effects. Difficulties in separating optical isomers often make it impractical to market stereochemically pure products or to monitor isomeric contamination. This is not thought to be a problem with drugs isolated from biological sources (the ... |
3437892 | Differential regulation of a hydroxyproline-rich glycoprotein gene family in wounded and infected plants. | We have characterized three different transcripts induced by fungal elicitor, wounding, or infection which encode apoproteins of cell wall hydroxyproline-rich glycoproteins involved in plant defense against infection. The proteins encoded by two of these transcripts contain a proline-rich domain involving tandem repeti... |
3435684 | The effect of SDS and 2-mercaptoethanol on the supramolecular structure of human gastric mucus gel. | The solubility of freshly obtained human gastric mucus gel was investigated using solutions of Tris buffer, urea, SDS, and 2-mercaptoethanol. The best solubility was achieved in SDS solution, whereas 2-mercaptoethanol did not solubilize mucus gel. The degree of mucus depolymerization with the solubilizers was evaluated... |
3435493 | A study of the interaction between cartilage proteoglycan and link protein. | The interaction between proteoglycan and link protein extracted from bovine articular cartilage (15-18-month-old animals) was investigated in 0.5 M-guanidinium chloride. The proteoglycans, radiolabelled as the aggregate (A1 fraction), were fractionated by two 'dissociative' density-gradient centrifugations (A1D1D1) fol... |
2449173 | Mouse alpha-macroglobulin. Structure, function and a molecular model. | Mouse alpha-macroglobulin (M-AMG) is believed to be a functional homologue of human alpha 2-macroglobulin (h-alpha 2M). The subunit composition, the tryptic cleavage pattern before and after methylamine incorporation and the two-dimensional tryptic-peptide mapping, however, indicate that these two proteins are structur... |
3429618 | Collagen binding in clinical isolates of Staphylococcus aureus. | Collagen binding was examined in 90 strains of Staphylococcus aureus derived from patient samples. Slightly under one-half (39 of 90) of the S. aureus strains bound collagen. Collagen binding in S. aureus did not correlate with either immunoglobulin G or fibronectin binding by these organisms. Chi-square analysis of is... |
3428926 | In vitro cellular immune response to measles viral glycoproteins: role of the antigen vector. | The capacity of measles virus and haemagglutinin (HA) and fusion (F) glycoproteins, presented either as soluble antigens, associated with liposomes or as Iscoms, to induce an in vitro primary and anamnestic cellular response was studied in syngeneic W/Fu rats using the MTT colorimetric assay. A primary cellular respons... |
3428690 | Significance of a fall in serum CEA concentration in patients treated with cytotoxic chemotherapy for disseminated colorectal cancer. | 'Tumour response', defined as clinical or radiological evidence of tumour shrinkage is frequently regarded as an objective of chemotherapy, rather than as a predictor of prolonged survival. This study has assessed whether a fall in the serum CEA concentration after chemotherapy for disseminated colorectal cancer is a p... |
3428274 | Promoter and enhancer elements containing a conserved sequence motif are recognized by nuclear factor III, a protein stimulating adenovirus DNA replication. | Nuclear factor III (NFIII) is a protein from HeLa cells that stimulates the initiation of adenovirus type 2 (Ad2) DNA replication by binding to a specific nucleotide sequence in the origin, adjacent to the nuclear factor I recognition site. DNA sequences sharing a high degree of homology to the NFIII binding site in Ad... |
2827761 | Experimental attempt to simulate receptor site environment. A 500-MHz 1H nuclear magnetic resonance study of enkephalin amides. | The amides of Leu5-enkephalin, Met5-enkephalin, and three analogues, D-Ala2,Leu5-enkephalin, (AcO)Tyr1,Met5-enkephalin, and (AcO)Tyr1,D-Ala2,Met5-enkephalin, have been studied by means of 1H NMR spectroscopy in two different solvent systems: Me2SO-d6 and CDCl3. In the latter solvent the peptides were dissolved as compl... |
3322021 | Brain amyloid in normal aging and cerebral amyloid angiopathy is antigenically related to Alzheimer's disease beta-protein. | Amyloid deposition is a prominent feature of a number of brain disorders, in which amyloid fibrils are found within blood vessel walls, the neuropil (neuritic plaques), neurons (neurofibrillary tangles). These include Alzheimer's disease (AD), AD changes associated with Down's syndrome, neurologically asymptomatic amyl... |
3480537 | A model of high-affinity antibody binding to type III group B Streptococcus capsular polysaccharide. | We recently reported that the single repeating-unit pentasaccharide of type III group B Streptococcus (GBS) capsular polysaccharide is only weakly reactive with type III GBS antiserum. To further elucidate the relationship between antigen-chain length and antigenicity, tritiated oligosaccharides derived from type III c... |
3321063 | Biochemical, immunological, and immunocytochemical evidence for the association of chalcone synthase with endoplasmic reticulum membranes. | Chalcone synthase [naringenin-chalcone synthase; malonyl-CoA:4-coumaroyl-CoA malonyltransferase (cyclizing), E.C. 2.3.1.74], the key enzyme of flavonoid pathways that was believed to be soluble, has been localized on ribosome-bearing endoplasmic reticulum membranes in the epidermis of buckwheat (Fagopyrum esculentum M.... |
2827160 | Enthalpy-entropy compensations in drug-DNA binding studies. | We present a comparative study of calorimetrically derived thermodynamic profiles for the binding of a series of drugs with selected DNA host duplexes. We use these data to demonstrate that comparisons between complete thermodynamic profiles (delta G zero, delta H zero, delta S zero, delta Cp) are required before drug ... |
3122208 | Helix stabilization by Glu-...Lys+ salt bridges in short peptides of de novo design. | Four alanine-based peptides were designed, synthesized, and tested by circular dichroism for alpha-helix formation in H2O. Each peptide has three glutamic/lysine residue pairs, is 16 or 17 amino acids long, and has blocked alpha-NH2 and alpha-COOH groups. In one set of peptides ("i+4"), the glutamic and lysine residues... |
3697085 | Selective inhibition of the cytopathic effect of type A influenza viruses by oligodeoxynucleotides covalently linked to an intercalating agent. | Oligodeoxynucleotides covalently linked to an acridine derivative were targeted to part of the 3'-terminal sequence which is common to the eight RNAs of type A influenza viruses. The cytopathic effect of the virus on MDCK cells in culture was strongly decreased by a heptanucleotide covalently attached to the acridine r... |
3697081 | Application of an immunoprecipitation procedure to the study of SV40 tumor antigen interaction with mouse genomic DNA sequences. | Simian Virus 40 (SV40) large T antigen is a DNA binding protein with high affinity for segments of the viral genome. To find out whether T antigen also binds to sequences of genomic cellular DNA we mixed T antigen and SAU 3 A restricted mouse DNA under stringent DNA binding conditions. Resulting protein-DNA complexes w... |
3320060 | Expression in Escherichia coli of a functional Dictyostelium myosin tail fragment. | The amino acid sequence of the myosin tail determines the specific manner in which myosin molecules are packed into the myosin filament, but the details of the molecular interactions are not known. Expression of genetically engineered myosin tail fragments would enable a study of the sequences important for myosin fila... |
3693404 | Effect of heavy chain phosphorylation on the polymerization and structure of Dictyostelium myosin filaments. | In Dictyostelium amebas, myosin appears to be organized into filaments that relocalize during cell division and in response to stimulation by cAMP. To better understand the regulation of myosin assembly, we have studied the polymerization properties of purified Dictyostelium myosin. In 150 mM KCl, the myosin remained i... |
2891714 | Temperature-dependent reversible assembly of taxol-treated microtubules. | Taxol is a plant alkaloid that binds to and strongly stabilizes microtubules. Taxol-treated microtubules resist depolymerization under a variety of conditions that readily disassemble untreated microtubules. We report here that taxol-treated microtubules can be induced to disassemble by a combination of depolymerizatin... |
3693401 | Erythrocyte adducin: a calmodulin-regulated actin-bundling protein that stimulates spectrin-actin binding. | Adducin is an erythrocyte membrane skeletal phosphoprotein comprised of two related subunits of 105,000 and 100,000 Mr. These peptides form a functional heterodimer, and the smaller of the two binds calmodulin in a calcium-dependent fashion. Although this protein has been physicochemically characterized, its function r... |
3320053 | Immunochemical localization of myosin heavy chain isoforms and paramyosin in developmentally and structurally diverse muscle cell types of the nematode Caenorhabditis elegans. | The nematode Caenorhabditis elegans contains two major groups of muscle cells that exhibit organized sarcomeres: the body wall and pharyngeal muscles. Several additional groups of muscle cells of more limited mass and spatial distribution include the vulval muscles of hermaphrodites, the male sex muscles, the anal-inte... |
3693393 | Basement membrane structure in situ: evidence for lateral associations in the type IV collagen network. | To determine molecular architecture of the type IV collagen network in situ, the human amniotic basement membrane has been studied en face in stereo relief by high resolution unidirectional metal shadow casting aided by antibody decoration and morphometry. The appearance of the intact basement membrane is that of a thi... |
2961742 | Self-assembly of a high molecular weight basement membrane heparan sulfate proteoglycan into dimers and oligomers. | A high molecular weight basement membrane heparan sulfate proteoglycan, isolated from murine Englebreth-Holm-Swarm tumor, is seen in platinum replicas as an elongated flexible core (Mr = 450,000) consisting of a series of tandem globular domains from which extend, at one end, two to three heparan sulfate chains (averag... |
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