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9251899 | Antiarrhythmic and electrophysiological effects of the novel KATP channel opener, rilmakalim, in rabbit cardiac cells. | 1. The effects of rilmakalim, a potassium channel opener, were studied on rabbit cardiac Purkinje, ventricular muscle and atrial fibers, with the use of conventional microelectrode techniques. 2. Rilmakalim (0.24-7.2 microM) shortened, in a concentration-dependent manner, the action potential duration (APD) in Purkinje... |
9251822 | Formation of stable polypeptide monolayers at interfaces: controlling molecular conformation and orientation. | The molecular self-organization and structural properties of peptide assemblies at different interfaces, using either amphipathic or hydrophobic polypeptide helices, is described. The two peptides under investigation form stable monolayers on the water surface under the conservation of their molecular conformation, as ... |
9251812 | Local dynamics of DNA probed with optical absorption spectroscopy of bound ethidium bromide. | We have studied the local dynamics of calf thymus double-helical DNA by means of an "optical labeling" technique. The study has been performed by measuring the visible absorption band of the cationic dye ethidium bromide, both free in solution and bound to DNA, in the temperature interval 360-30 K and in two different ... |
9251799 | Pore formation and translocation of melittin. | Melittin, a bee venom, is a basic amphiphilic peptide, which mainly acts on the lipid matrix of membranes, lysing various cells. To elucidate the molecular mechanism, we investigated its interactions with phospholipid vesicles. The peptide formed a pore with a short lifetime in the membrane, as revealed by the release ... |
9251793 | Intrinsic rectification of ion flux in alamethicin channels: studies with an alamethicin dimer. | Covalent dimers of alamethicin form conducting structures with gating properties that permit measurement of current-voltage (I-V) relationships during the lifetime of a single channel. These I-V curves demonstrate that the alamethicin channel is a rectifier that passes current preferentially, with voltages of the same ... |
9251779 | The pore-lining region of shaker voltage-gated potassium channels: comparison of beta-barrel and alpha-helix bundle models. | Although there is a large body of site-directed mutagenesis data that identify the pore-lining sequence of the voltage-gated potassium channel, the structure of this region remains unknown. We have interpreted the available biochemical data as a set of topological and orientational restraints and employed these restrai... |
9251778 | Simulations of nucleation and early growth stages of protein crystals. | Analysis of known protein crystal structures reveals that interaction energies between monomer pairs alone are not sufficient to overcome entropy loss related to fixing monomers in the crystal lattice. Interactions with several neighbors in the crystal are required for stabilization of monomers in the lattice. A micros... |
9250108 | Acetylation of or beta-cyclodextrin addition to potato beneficial effect on glucose metabolism and appetite sensations. | Functional foods are gaining more and more interest from health scientists. One way to improve the nutritional properties of foods may be to modify the starch component, often included to stabilize the food product. In this study two chemically modified starches-a 1-2% acetylated potato starch and a starch enriched wit... |
9245790 | Spindle assembly in Xenopus egg extracts: respective roles of centrosomes and microtubule self-organization. | In Xenopus egg extracts, spindles assembled around sperm nuclei contain a centrosome at each pole, while those assembled around chromatin beads do not. Poles can also form in the absence of chromatin, after addition of a microtubule stabilizing agent to extracts. Using this system, we have asked (a) how are spindle pol... |
9245426 | Trapping and characterization of the reaction intermediate in cyclodextrin glycosyltransferase by use of activated substrates and a mutant enzyme. | Cyclodextrin glycosyltransferases (CGTases) catalyze the degradation of starch into linear or cyclic oligosaccharides via a glycosyl transfer reaction occurring with retention of anomeric configuration. They are also shown to catalyze the coupling of maltooligosaccharyl fluorides. Reaction is thought to proceed via a d... |
9241253 | RNA-protein interactions within the 3 ' untranslated region of vimentin mRNA. | Several functions have been attributed to protein binding within the 3'untranslated region (3'UTR) of mRNA, including mRNA localization, stability, and translational repression. Vimentin is an intermediate filament protein whose 3'untranslated sequence is highly conserved between species. In order to identify sequences... |
9239402 | Modification of apolipoprotein(a) lysine binding site reduces atherosclerosis in transgenic mice. | Lipoprotein(a) contributes to the development of atherosclerosis through the binding of its plasminogen-like apolipoprotein(a) component to fibrin and other plasminogen substrates. Apolipoprotein(a) contains a major lysine binding site in one of its kringle domains. Destruction of this site by mutagenesis greatly reduc... |
9244262 | Lipase secretion by bacterial hybrid ATP-binding cassette exporters: molecular recognition of the LipBCD, PrtDEF, and HasDEF exporters. | Serratia marcescens secretes several proteins, such as the lipase LipA, the metalloprotease PrtA, and the heme-binding protein HasA, which is required for heme acquisition, through two N-terminal signal peptide-independent systems that are classified as bacterial ATP-binding cassette (ABC) exporters. One is the ABC exp... |
9244252 | Identification and characterization of an operon of Helicobacter pylori that is involved in motility and stress adaptation. | We identified a novel stress-responsive operon (sro) of Helicobacter pylori that contains seven genes which are likely to be involved in cellular functions as diverse as chemotaxis, heat shock response, ion transport, and posttranslational protein modification. The products of three of these genes show amino acid homol... |
9238058 | A natural polymorphism in beta-lactamase is a global suppressor. | A M182T substitution was discovered as a second-site suppressor of a missense mutation in TEM-1 beta-lactamase. The combination of the M182T substitution with other substitutions in the enzyme indicates the M182T substitution is a global suppressor of missense mutations in beta-lactamase. The M182T substitution also is... |
9234993 | Imaging of individual biopolymers and supramolecular assemblies using noncontact atomic force microscopy. | A variety of biopolymers is imaged using noncontact atomic force microscopy. Samples are prepared by aerosol spray deposition of aqueous solutions on freshly cleaved mica followed by air drying. The distributions of contour lengths and chain or fibril thicknesses normal to the mica substrate can be measured for individ... |
9271090 | Evidence for the formation of a heterotrimeric complex of leukaemia inhibitory factor with its receptor subunits in solution. | Leukaemia inhibitory factor (LIF) is a polyfunctional cytokine that is known to require at least two distinct receptor components (LIF receptor alpha-chain and gp130) in order to form a high-affinity, functional, receptor complex. Human LIF binds with unusually high affinity to a naturally occurring mouse soluble LIF r... |
9271074 | Kinetoplastid glucose transporters. | Protozoa of the order kinetoplastida have colonized many habitats, and several species are important parasites of humans. Adaptation to different environments requires an associated adaptation at a cell's interface with its environment, i.e. the plasma membrane. Sugar transport by the kinetoplastida as a phylogenetical... |
9224602 | Synthesis and hybridization properties of inverse oligonucleotides. | The synthesis of adenine and thymine cyclopentylethyl nucleosides is presented. This novel constrained monomeric building block is very difficult to incorporate into oligonucleotides. It was introduced in 13mer oligodeoxynucleotide sequences at a single position using H-phosphonate chemistry. Phosphoramidite chemistry ... |
9221789 | AMPA receptor facilitation accelerates fear learning without altering the level of conditioned fear acquired. | Rats treated with the AMPA receptor-facilitating drug 1-(quinoxolin-6-ylcarbonyl)piperidine (BDP-12) during training acquired fear conditioning to a tone faster than vehicle-treated controls. The effect on acquisition was dependent on the dose given. BDP-12-treated rats and vehicle-treated controls reached the same lev... |
9223527 | Characterization of a human papillomavirus type 16 variant-dependent neutralizing epitope. | We have determined that three type-specific and conformationally dependent monoclonal antibodies, H16.E70, H16.U4, and H16.V5, neutralize pseudotype human papillomavirus type 16 (HPV16) virions in vitro. H16.U4 and H16.V5 neutralized pseudotype virions derived from the German HPV16 variant 114K and the Zairian variant ... |
9223495 | Enhancement of human immunodeficiency virus type 1 envelope-mediated fusion by a CD4-gp120 complex-specific monoclonal antibody. | The entry of human immunodeficiency virus type 1 (HIV-1) into cells is initiated by binding of the viral glycoprotein gp120-gp41 to its cellular receptor CD4. The gp120-CD4 complex formed at the cell surface undergoes conformational changes that may allow its association with an additional membrane component(s) and the... |
9223492 | Immunodominant CD4+ T-cell epitope within nonstructural protein 3 in acute hepatitis C virus infection. | In acute hepatitis C virus infection, 50 to 70% of patients develop chronic disease. Considering the low rate of spontaneous viral clearance during chronic hepatitis C infection, the first few months of interaction between the patient's immune system and the viral population seem to be crucial in determining the outcom... |
9223482 | Consequences of a subtle sialic acid modification on the murine polyomavirus receptor. | Polyomaviruses are small, nonenveloped DNA tumor viruses with restricted host ranges. Virus binding to cell surface receptors is one determinant of viral tropism. Although murine polyomavirus is among the best characterized viruses, little is known about the sialic acid-containing receptor and its interaction with vira... |
21639386 | Characterizing oligosaccharides using injected-ion mobility/mass spectrometry. | Injected-ion mobility/mass spectrometry techniques have been used to measure the reduced ion mobilities for negatively charged raffinose, melezitose and α-, β-, and γ-cyclodextrins formed by electrospray ionization. At low injection energies, the mass spectra are dominated by negatively charged (deprotonated) parent io... |
21639372 | Applications of sol-gel-derived membranes to neutral carrier-type ion-sensitive field-effect transistors. | Sol-gel-derived membranes encapsulating neutral carriers, such as valinomycin and a bis(crown ether) derivative, were fabricated as novel ion-sensing membranes for neutral carrier-type ion-sensitive field-effect transistors (ISFETs). The neutral carrier-type sol-gel-derived membranes obtained with an initial diethoxydi... |
11669943 | Selective Binding of Trivalent Metals by Hexahomotrioxacalix[3]arene Macrocycles: Determination of Metal-Binding Constants and Metal Transport Studies. | The hexahomotrioxacalix[3]arene macrocycles 1a,b are observed to bind Sc(3+), Lu(3+), Y(3+), and La(3+) more strongly than alkali or alkaline earth metal ions. Binding constants have been determined for the trivalent metal ions using an NMR titration method and are observed to increase with increasing charge-to-radius ... |
11038556 | Polycaps: reversibly formed polymeric capsules. | Described are assemblies consisting of polymeric capsules, "polycaps," formed from two calix[4]arene tetraureas covalently connected at their lower rims. In these structures self-assembly leads to reversibly formed capsule sites along a chain, reminiscent of beads on a string. Their dynamic behavior is characterized by... |
15739464 | [Chiral separation of racemic 5-(p-hydroxyphenyl)-5-phenylhydantoin by RP-HPLC using eluents containing beta-cyclodextrin]. | A chiral RP-HPLC method was developed to assay the 5-(p-hydroxyphenyl)-5-Phenylhydantoin (p-HPPH) enantiomers, the major metabolite of antiepileptic drug phenytoin, in rat hepatic microsomes. A 50 mm FLC-C8 column was used as the analytical column, beta-cyclodextrin (beta-CD) as chiral mobile phase additive and phenoba... |
15299915 | Structure of apo duck ovotransferrin: the structures of the N and C lobes are in the open form. | The structure of apo duck ovotransferrin (APODOT) has been determined at a resolution of 4.0 A by the molecular replacement method using the structure of duck ovotransferrin (DOT) as the search model. The DOT structure contains two iron binding sites; one in the N-terminal lobe lying between domains N1 and N2 and one i... |
9476523 | The mobility of troponin C and troponin I in muscle. | In vertebrate skeletal muscle, contraction is initiated by the elevation of the intracellular Ca2+ concentration. The binding of Ca2+ to TnC induces a series of conformational changes which ultimately release the inhibition of the actomyosin ATPase activity by Tnl. In this study we have characterized the dynamic behavi... |
9476522 | Dynamic aspects of the incorporation of proteins into biological membranes. | The contributions of intramembranous and extramembranous segments of transmembrane proteins to frictional forces have been studied by covalently attached 14N- and 15N-indane dione and maleimide spin labels using saturation transfer electron spin resonance spectroscopy. The role of molecular size and membrane viscosity ... |
9476521 | Studies of metabolic control using NMR and molecular genetics. | The techniques of NMR spectroscopy and molecular genetics have provided new and powerful approaches to studying the control and organisation of cellular metabolism in vivo. We review here our recent applications of these methodologies to the study of energy metabolism in yeast and mammalian cells. |
9476520 | Recognition of E. coli tryptophan synthase by single-chain Fv fragments: comparison of PCR-cloning variants with the parental antibodies. | The use of a recombinant antibody fragment instead of a complete antibody, as a conformational probe for protein structure and folding studies, can be technically advantageous provided that the recombinant fragment and its parental antibody recognize the antigen through the same mechanism. Monoclonal antibodies mAb19 a... |
9476519 | A computational study of a host-guest complex. | The geometry and energetics of a complex involving pyrazine and an acridine diacid cleft-like host designed by Rebek were investigated at several levels of theory. Molecular mechanics (using the Tripos and CHARMm force fields), semiempirical quantum chemical approaches (with the AM1 and PM3 methods), and an ab initio q... |
9312402 | Protein folding: concepts and perspectives. | In this review, the main concepts of protein folding, as deduced from both theoretical and experimental in vitro studies, are presented. The thermodynamic aspects from Anfinsen's postulate, Levinthal's paradox to the concept of folding funnel as proposed by Wolynes and coworkers are described. Concerning the folding pa... |
9296361 | A basic compositional requirement of agents having heparin-like cell-modulating activities. | Heparin has been recognized as possessing a large variety of cell-modulating activities. Using compositionally simple, structurally rigid, and low molecular weight saccharide molecules (cyclodextrins), we demonstrated that these activities depend primarily on a single, gross compositional parameter: a minimum intramole... |
9281852 | Peptide epitope mapping in vaccine development: introduction. | Protection from infectious disease by the host immune response requires specific molecular recognition of unique antigenic determinants of a given pathogen. An epitope is an antigenic determinant which: 1) specifically stimulates the immune response (either B or T cell mediated); and 2) is acted upon by the products of... |
9276678 | Glycosylation of human bone collagen I in relation to lysylhydroxylation and fibril diameter. | Posttranslational modifications (lysylhydroxylation, glycosylation, and crosslink formation) of collagen I and the trabecular bone volume (TBV) as well as the supramolecular organization of human vertebrae were studied by analyzing vertebral bones of 55 individuals (22-93 years of age). The degree of lysylhydroxylation... |
9271139 | Chiral separation of primary amino compounds using a non-chiral crown ether with beta-cyclodextrin by capillary electrophoresis. | A non-chiral crown ether (18-crown-6) along with beta-cyclodextrin (beta-CD) was used to achieve enantioselective separations of primary amino compounds in capillary electrophoresis. In this new method, the amino group of these compounds is protonated in a low pH separation buffer and forms a selective host-guest compl... |
9304360 | [The circulating adhesion molecules sICAM-1 and sP-selectin in patients with sepsis]. | <h4>Aim</h4>The aim of this study was to investigate whether the plasma levels of the circulating adhesion molecules sICAM-1 and sE-selectin could serve as early predictors of developing sepsis and its severity.<h4>Methods</h4>Twenty-four patients admitted to an intensive care unit with a high risk of developing septic... |
9266694 | The pipecolate-incorporating enzyme for the biosynthesis of the immunosuppressant rapamycin--nucleotide sequence analysis, disruption and heterologous expression of rapP from Streptomyces hygroscopicus. | An open reading frame (rapP) encoding the putative pipecolate-incorporating enzyme (PIE) has been identified in the gene cluster for the biosynthesis of rapamycin in Streptomyces hygroscopicus. Conserved amino acid sequence motifs for ATP binding, ATP hydrolysis, adenylate formation, and 4'-phosphopantetheine attachmen... |
9263638 | A limitation of two-state analysis for transitions between disordered and weakly ordered states. | <h4>Background</h4>The stability of the secondary structure of particular peptide regions is often used to investigate the involvement of the region in protein folding. When analysing the relatively small populations of associated states that are formed by weak interactions (i.e. those interactions that are comparable ... |
9260672 | HPCE determination of R(+) and S(-) mepivacaine in human serum using a derivatized cyclodextrin and ultraviolet detection. | A high performance capillary electrophoresis assay for the quantitative determination of R(+) and S(-) mepivacaine in human serum is reported using heptakis (2,6-di-O-methyl) beta-cyclodextrin as the chiral selector for the separation of the enantiomers. The background electrolyte was a 100 mM phosphate buffer (pH 2.5)... |
9261584 | Infected pancreatic necrosis complicated by multiple organ failure. | <h4>Background/aims</h4>Sixteen patients with bacteriologically proven severe infected pancreatic necrosis (IPN) undergoing sequential surgical treatment were studied prospectively.<h4>Methodology</h4>The severity of IPN was documented pre-operatively using the following scores: 1) degree of necrosis by CT scan [< 30% ... |
9257000 | Separation of chiral amino acids by micellular electrokinetic chromatography with derivatized cyclodextrins. | The chiral separation of several amino acid (AA) enantiomers derivatized with naphthalene-2,3-dialdehyde (NDA) was achieved by use of cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC). Both neutral hydroxypropyl beta-cyclodextrin (HP-beta-CD) and charged carboxymethyl beta-cyclodextrin (CM-beta-CD)... |
9256995 | Chiral separations of enantiomeric pharmaceuticals by capillary electrophoresis using sulphobutyl ether beta-cyclodextrin as isomer selector. | Capillary electrophoresis has developed into an extremely useful technique for the separation of optical isomers. High efficiencies and the availability of many types of isomer selectors allowing rapid and inexpensive methods development make capillary electrophoresis (CE) an attractive alternative to gas chromatograph... |
9255967 | Preparation of oligosaccharide units library and its utilization. | There is high current interest in developing synthetic routes to oligosaccharides involved in glycoconjugates. Significant attention has been focused on the application of glycosidase-catalyzed transglycosylation for practical synthesis of oligosaccharides. The enzymatic synthesis has become more practical by the use o... |
9253189 | Enantioselective determination of chiral organochlorine compounds in biota by gas chromatography on modified cyclodextrins. | Approaches to the gas chromatographic enantiomer separation of chiral organchlorines (alpha-hexachlorocyclohexane, cis- and trans-chlordane, heptachlor, heptachlorepoxide, oxychlordane, o,p'-DDT, compounds of technical toxaphene and stable atropisomeric polychlorinated biphenyls) are reviewed. Chiral stationary phases ... |
9251480 | [Surgical treatment of thoracic aorta for elderly patient]. | From 1986 to 1996, 237 patients underwent surgical treatment of thoracic aorta in our institute. We classified them as follows: group 1 is 41 patients older than 75: group 2 is 196 patients younger than 74. The number of patients of elective surgery, emergent surgery for acute dissection type A and emergent surgery for... |
9252051 | Analysis of some metabolites of organic solvents in urine by high-performance liquid chromatography with beta-cyclodextrin. | Chromatographic separation of the metabolites derived from toluene, ethylbenzene, styrene and xylene was carried out on untreated urine samples from factory workers. The elution sequence was as follows: phenylglyoxilic acid, 3-hydroxy-2-butanone, hippuric acid, o-methylhippuric acid, p-methylhippuric acid, m-methylhipp... |
9249950 | Direct preparation of cyclodextrin monophosphates. | Aqueous solutions of cyclodextrins and inorganic metaphosphate at pH 4, upon drying and subsequent warming, produce mixtures of isomeric monophosphate esters which are amenable to separation by anion-exchange chromatography. The products are characterised by enzymatic, mass, and NMR spectroscopic analysis. The methodol... |
9249524 | A novel cardioprotective function of adenosine A1 and A3 receptors during prolonged simulated ischemia. | The possible cardioprotective roles of adenosine A1 and A3 receptors were investigated in a cardiac myocyte model of injury. The adenosine A3 receptor is a novel cardiac receptor capable of mediating potentially important cardioprotective functions. Prolonged hypoxia with glucose deprivation was used to simulate ischem... |
9250692 | Intermediates in the assembly pathway of the double-stranded RNA virus phi6. | The double-stranded RNA bacteriophage phi6 contains a nucleocapsid enclosed by a lipid envelope. The nucleocapsid has an outer layer of protein P8 and a core consisting of the four proteins P1, P2, P4 and P7. These four proteins form the polyhedral structure which acts as the RNA packaging and polymerase complex. Simul... |
9250688 | Reprogramming the purine nucleotide cofactor requirement of Drosophila P element transposase in vivo. | Guanosine triphosphate (GTP)-binding proteins are involved in controlling a wide range of fundamental cellular processes. In vitro studies have indicated a role for GTP during Drosophila P element transposition. Here we show that P element transposase contains a non-canonical GTP-binding domain that is critical for its... |
9250665 | Normal development but differentially altered proliferative responses of lymphocytes in mice lacking CD81. | CD81 (TAPA-1) is a member of the transmembrane 4 superfamily (TM4SF) which is expressed on the cell surface of most cells of the body throughout their cellular differentiation. It has been recognized in several cell surface complexes of lymphocytes, suggesting that it may have diverse roles in lymphocyte development an... |
9247710 | Formation of homo- and heterooligomeric supramolecular structures by D-glyceraldehyde-3-phosphate dehydrogenase and lactate dehydrogenase in reversed micelles of aerosol OT in octane. | The supramolecular structure of oligomeric enzymes can be specifically regulated by changing the size of an inner cavity of Aerosol OT reversed micelles in octane. Both D-glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and lactate dehydrogenase (LDH) reveal an ability to exist and function in monomeric, dimeric and te... |
9249028 | Mode of primary binding to target membranes and pore formation induced by Vibrio cholerae cytolysin (hemolysin). | Vibrio cholerae cytolysin (VCC) is produced by many non-choleratoxigenic strains of V. cholerae, and possibly represents a relevant pathogenicity determinant of these bacteria. The protein is secreted as a pro-toxin that is proteolytically cleaved to yield the active toxin with a molecular mass of approximately 63 kDa.... |
9246772 | Influence of medium composition on the growth and antigen expression of Helicobacter pylori. | An evaluation of the ability of various solid and liquid media to support both growth and antigen expression, particularly lipopolysaccharide (LPS) expression, by Helicobacter pylori culture collection strains and clinical isolates was performed. Liquid-based basal media (brain heart infusion, Brucella broth, Mueller-H... |
9241857 | Polysulfated carbohydrates analyzed as ion-paired complexes with basic peptides and proteins using electrospray negative ionization mass spectrometry. | Electrospray ionization mass spectrometry was used in the negative ion mode to analyze complexes of sucrose octasulfate, sucrose heptasulfate and sulfated alpha-, beta- and gamma-cyclodextrins with synthetically prepared basic peptides, the basic protein ubiquitin and polyamines. The spectra presented demonstrate that ... |
9237897 | Dendritic nucleic acid structures. | Dendritic molecules are highly-branched arborescent structures and have found applications as chemical reagents, lubricants, contrast media for magnetic resonance, and others. Dendritic nucleic acids could be extremely useful for the development of nucleic acid diagnostics as signal amplification tools and potentially ... |
9241094 | Improved bioavailability and clinical response in patients with chronic liver disease following the administration of a spironolactone: beta-cyclodextrin complex. | <h4>Aims</h4>To compare the absorption and clinical effect of spironolactone from an inclusion complex with beta-cyclodextrin (SP-COMP) to Aldactone tablets (ALD) in chronic liver disease.<h4>Methods</h4>Patients, admitted with chronic liver disease, completed a randomized crossover steady state study. They received th... |
9233812 | Region 2.5 of the Escherichia coli RNA polymerase sigma70 subunit is responsible for the recognition of the 'extended-10' motif at promoters. | At some bacterial promoters, a 5'-TG-3' sequence element, located one base upstream of the -10 hexamer element, provides an essential motif necessary for transcription initiation. We have identified a mutant of the Escherichia coli RNA polymerase sigma70 subunit that has an altered preference for base sequences in this... |
9233809 | Transcriptional regulation in endoderm development: characterization of an enhancer controlling Hnf3g expression by transgenesis and targeted mutagenesis. | The hepatic nuclear factor 3gamma (Hnf3g) is a member of the winged helix gene family of transcription factors and is thought to be involved in anterior-posterior regionalization of the primitive gut. In this study, cis-regulatory elements essential for the expression of Hnf3g in vivo have been characterized. To this e... |
9232654 | Mutational analysis of hydrophobic domain interactions in gamma B-crystallin from bovine eye lens. | gamma B-crystallin is a monomeric member of the beta gamma-superfamily of vertebrate eye lens proteins. It consists of two similar domains with all-beta Greek key topology associating about an approximate two-fold axis. At pH 2, with urea as the denaturant, the domains show independent equilibrium unfolding transitions... |
9232653 | Structural studies of receptor binding by cholera toxin mutants. | The wide range of receptor binding affinities reported to result from mutations at residue Gly 33 of the cholera toxin B-pentamer (CTB) has been most puzzling. For instance, introduction of an aspartate at this position abolishes receptor binding, whereas substitution by arginine retains receptor affinity despite the l... |
9232520 | Nasal absorption of dihydroergotamine from liquid and powder formulations in rabbits. | Nasal drug delivery is an interesting route of administration for dihydroergotamine in migraine therapy. The currently available formulation contains dihydroergotamine at 4 mg/mL. For a nasal dose of 2 mg, a volume of 0.5 mL has to be administered, which sometimes leads to spillage of the formulation. The aim of the pr... |
9228019 | Constitutive activation of the beta2 adrenergic receptor alters the orientation of its sixth membrane-spanning segment. | The binding site of the beta2 adrenergic receptor, like that of other homologous G-protein-coupled receptors, is contained within a water-accessible crevice formed among its seven membrane-spanning segments. Methanethiosulfonate ethylammonium (MTSEA), a charged, hydrophilic, lipophobic, sulfhydryl-specific reagent, had... |
9227858 | Yeast killer systems. | The killer phenomenon in yeasts has been revealed to be a multicentric model for molecular biologists, virologists, phytopathologists, epidemiologists, industrial and medical microbiologists, mycologists, and pharmacologists. The surprisingly widespread occurrence of the killer phenomenon among taxonomically unrelated ... |
9225751 | 17 beta-estradiol attenuates fimbrial lesion-induced decline of ChAT-immunoreactive neurons in the rat medial septum. | We investigated the neuroprotective effects of 17 beta-estradiol (E2) on medial septal cholinergic neurons following partial unilateral lesion of the fimbriafornix. Adult female rats were ovariectomized (OVX) and, 5 days later, treated with a single intravenous (iv) injection of an estradiol (E2)-chemical delivery syst... |
9221761 | Human peripheral blood eosinophils express a functional c-kit receptor for stem cell factor that stimulates very late antigen 4 (VLA-4)-mediated cell adhesion to fibronectin and vascular cell adhesion molecule 1 (VCAM-1). | We evaluated mature peripheral blood eosinophils for their expression of the surface tyrosine kinase, c-kit, the receptor for the stromal cell-derived cytokine, stem cell factor (SCF). Cytofluorographic analysis revealed that c-kit was expressed on the purified peripheral blood eosinophils from 8 of 8 donors (4 nonatop... |
9223178 | Mean field analysis of FKBP12 complexes with FK506 and rapamycin: implications for a role of crystallographic water molecules in molecular recognition and specificity. | Mean field analysis of FKBP12 complexes with FK506 and rapamycin has been performed by using structures obtained from molecular docking simulations on a simple, yet robust molecular recognition energy landscape. When crystallographic water molecules are included in the simulations as an extension of the FKBP12 protein ... |
9222552 | Interaction of a new bis-indol derivative, KAR-2 with tubulin and its antimitotic activity. | 1. KAR-2 (3"-(beta-chloroethyl)-2",4"-dioxo-3,5"-spiro-oxazolidino- 4-deacetoxy-vinblastine), is a bis-indol derivative; catharantine is coupled with the vindoline moiety which contains a substituted oxazolidino group. Our binding studies showed that KAR-2 exhibited high affinity for bovine purified brain tubulin (Kd-3... |
9220982 | Fluoride binding in hemoproteins: the importance of the distal cavity structure. | The electronic absorption and resonance Raman spectra of the fluoride complexes of various peroxidases and selected site-directed mutants have been studied at pH 5.0, and compared to the spectra obtained for the myoglobin-F adduct. It is shown that the electronic absorption maxima depend on the degree of conjugation be... |
9220158 | Expression, characterization, and immunoreactivities of a soluble hepatitis E virus putative capsid protein species expressed in insect cells. | The hepatitis E virus (HEV) open reading frame-2 (ORF-2) is predicted to encode a 71-kDa putative capsid protein involved in virus particle formation. When insect Spodoptera frugiperda (Sf9) cells were infected with a recombinant baculovirus containing the entire ORF-2 sequence, two types of recombinant proteins were p... |
9219841 | Effect of chemical structure and hydrophobicity on the pharmacokinetic properties of porphycenes in tumour-bearing mice. | The efficiency and selectivity of tumour targeting by several tetra-n-propylporphycene (TPPn) and tetrakis(methoxyethyl)porphycene (TMPn) derivatives have been studied by administering 3.76 micromol/kg of aqueous or liposomal porphycene formulations to BALB/c mice bearing an i.m. implanted MS-2 fibrosarcoma. These 2 pa... |
9211910 | Two modes of ligand binding in maltose-binding protein of Escherichia coli. Functional significance in active transport. | In the preceding two papers (Hall, J. A., Gehring, K., and Nikaido, H. (1997) J. Biol. Chem. 272, 17605-17609; Hall, J. A., Thorgeirson, T. E., Liu, J., Shin, Y.-E., and Nikaido, H. (1997) J. Biol. Chem. 272, 17610-17614), we showed that ligands that bind to the Escherichia coli maltose-binding protein (MBP) without pr... |
9211909 | Two modes of ligand binding in maltose-binding protein of Escherichia coli. Electron paramagnetic resonance study of ligand-induced global conformational changes by site-directed spin labeling. | Binding of ligands to the maltose-binding protein (MBP) of Escherichia coli often causes a global conformational change involving the closure of its two lobes. We have introduced a cysteine residue onto each of these lobes by site-directed mutagenesis and modified these residues with spin labels. Using EPR spectroscopy... |
9211908 | Two modes of ligand binding in maltose-binding protein of Escherichia coli. Correlation with the structure of ligands and the structure of binding protein. | Ligands that are transported by the maltose transport system of Escherichia coli must first bind to the periplasmic maltose-binding protein (MBP). However, binding of a ligand does not always lead to its transport. As reported earlier, reduced or oxidized maltodextrins bind tightly to MBP but are not transported; some ... |
9214390 | Bi-transgenic mice reveal that K-rasVal12 augments a p53-independent apoptosis when small intestinal villus enterocytes reenter the cell cycle. | Studies in cell culture systems have indicated that oncogenic forms of Ras can affect apoptosis. Activating mutations of Ras occur in approximately 30% of all human tumors and 50% of colorectal carcinomas. Since these mutations appear at early or intermediate stages in multistep journeys to neoplasia, an effect on apop... |
9214377 | Human cytomegalovirus immediate early interaction with host nuclear structures: definition of an immediate transcript environment. | The development of an induced transcript environment was investigated at the supramolecular level through comparative localization of the human cytomegalovirus immediate early (IE) transcripts and specific nuclear domains shortly after infection. Compact aggregates of IE transcripts form only adjacent to nuclear domain... |
9230107 | The peptide LSARLAF causes platelet secretion and aggregation by directly activating the integrin alphaIIbbeta3. | A novel peptide (designed to bind to alphaIIbbeta3) caused platelet aggregation and aggregation-independent secretion of the contents of alpha-granules in an alphaIIbbeta3-dependent fashion. The agonist peptide induced secretion in the presence of prostaglandin E1. In cell-free assays, alphaIIbbeta3 bound specifically ... |
9218612 | CD44 regulates phagocytosis of apoptotic neutrophil granulocytes, but not apoptotic lymphocytes, by human macrophages. | Phagocytosis of apoptotic neutrophil granulocytes by macrophages at inflammatory sites is an important determinant of the process by which inflammation resolves. We demonstrate that phagocytosis of apoptotic neutrophils, but not apoptotic lymphocytes, by human monocyte-derived macrophages is augmented rapidly following... |
9212923 | Therapeutic and physiological artificial heart: future prospects. | Current left ventricular assist devices (LVADs) have demonstrated admirable results. However, approximately one-fourth of the patients who require LVADs suffer from right heart failure and require additional right ventricular (RV) assist devices (RVADs). The RV failure impairs the splanchnic circulation, subsequently d... |
9212747 | Reactive oxygen species cause direct damage of Engelbreth-Holm-Swarm matrix. | Reactive oxygen species (ROS) are produced and released into the extracellular spaces in numerous diseases and contribute to development and progression, for example, of inflammatory diseases, proteinuria, and tumor invasion. However, little is known about ROS-induced chemical changes of interstitial matrix proteins an... |
9212434 | A novel means to develop strain-specific DNA probes for detecting bacteria in the environment. | A simple means to develop strain-specific DNA probes for use in monitoring the movement and survival of bacteria in natural and laboratory ecosystems was developed. The method employed amplification of genomic DNA via repetitive sequence-based PCR (rep-PCR) using primers specific for repetitive extragenic palindromic (... |
9210684 | Activity of the triazole SCH 56592 against disseminated murine coccidioidomycosis. | SCH 56592 (SCH) is a new triazole antifungal with a broad spectrum of activity. In vitro susceptibility testing against five strains of Coccidioides immitis revealed MICs from 0.39 to 3.13 microg/ml and minimal fungicidal concentrations from 1.56 to 3.13 microg/ml. A murine model of systemic coccidioidomycosis was esta... |
9210678 | Discovery of cyanovirin-N, a novel human immunodeficiency virus-inactivating protein that binds viral surface envelope glycoprotein gp120: potential applications to microbicide development. | We have isolated and sequenced a novel 11-kDa virucidal protein, named cyanovirin-N (CV-N), from cultures of the cyanobacterium (blue-green alga) Nostoc ellipsosporum. We also have produced CV-N recombinantly by expression of a corresponding DNA sequence in Escherichia coli. Low nanomolar concentrations of either natur... |
9210674 | Efficacy of SCH-56592 in a temporarily neutropenic murine model of invasive aspergillosis with an itraconazole-susceptible and an itraconazole-resistant isolate of Aspergillus fumigatus. | SCH-56592 (SCH) is a novel triazole antifungal agent with excellent in vitro activity against Aspergillus. We compared three doses (5, 10, and 25 mg/kg of body weight) of SCH with itraconazole (ITZ; 25 mg/kg) and amphotericin B (AB; 5 mg/kg) in a temporarily neutropenic murine model of disseminated aspergillosis (lungs... |
9207121 | Recombinant parvovirus-like particles as an antigen carrier: a novel nonreplicative exogenous antigen to elicit protective antiviral cytotoxic T cells. | To develop a strategy that promotes efficient antiviral immunity, hybrid virus-like particles (VLP) were prepared by self-assembly of the modified porcine parvovirus VP2 capsid protein carrying a CD8(+) T cell epitope from the lymphocytic choriomeningitis virus nucleoprotein. Immunization of mice with these hybrid pseu... |
9207080 | HLA class I and II antigens are partially co-clustered in the plasma membrane of human lymphoblastoid cells. | Major histocompatibility complex (MHC) class II molecules displayed clustered patterns at the surfaces of T (HUT-102B2) and B (JY) lymphoma cells characterized by interreceptor distances in the micrometer range as detected by scanning force microscopy of immunogold-labeled antigens. Electron microscopy revealed that a ... |
9209048 | Identification of a monooxygenase from Streptomyces coelicolor A3(2) involved in biosynthesis of actinorhodin: purification and characterization of the recombinant enzyme. | The oxidation of phenols to quinones is an important reaction in the oxidative tailoring of many aromatic polyketides from bacterial and fungal systems. Sequence similarity between ActVA-Orf6 protein from the actinorhodin biosynthetic cluster and the previously characterized TcmH protein that is involved in tetracenomy... |
9207044 | Stability, specificity and fluorescence brightness of multiply-labeled fluorescent DNA probes. | In this work, we studied the fluorescence and hybridization of multiply-labeled DNA probes which have the hydrophilic fluorophore 1-(straightepsilon-carboxypentynyl)-1'-ethyl- 3,3,3', 3'-tetramethylindocarbocyanine-5,5'-disulfonate (Cy3) attached via either a short or long linker at the C-5 position of deoxyuridine. We... |
9207024 | DNA containing 4'-thio-2'-deoxycytidine inhibits methylation by HhaI methyltransferase. | 4'-Thio-2'-deoxycytidine was synthesized as a 5'- protected phosphoramidite compatible with solid phase DNA synthesis. When incorporated as the target cytosine (C*) in the GC*GC recognition sequence for the DNA methyltransferase M. HhaI, methyl transfer was strongly inhibited. In contrast, these same oligonucleotides w... |
9207018 | A new peptide vector for efficient delivery of oligonucleotides into mammalian cells. | The development of antisense and gene therapy has focused mainly on improving methods for oligonucleotide and gene delivery into cells. In the present work, we describe a potent new strategy for oligonucleotide delivery based on the use of a short peptide vector, termed MPG (27 residues), which contains a hydrophobic d... |
9207003 | An interleukin 5 mutant distinguishes between two functional responses in human eosinophils. | Interleukin 5 (IL-5) is the key cytokine involved in regulating the production and many of the specialized functions of mature eosinophils including priming, adhesion, and survival. We have generated a point mutant of human IL-5, IL-5 (E12K), which is devoid of agonist activity in both a TF-1 cell proliferation assay a... |
9202017 | Seminiferous tubule basement membrane. Composition and organization of type IV collagen chains, and the linkage of alpha3(IV) and alpha5(IV) chains. | Seminiferous tubule basement membrane (STBM) plays an important role in spermatogenesis. In the present study, the composition and structural organization of type IV collagen of bovine STBM was investigated. STBM was found to be composed of all six alpha-chains of type IV collagen based upon immunocytochemical and bioc... |
9199805 | Hydrolysis of GTP associated with the formation of tubulin oligomers is involved in microtubule nucleation. | Hydrolysis of GTP is known to accompany microtubule assembly. Here we show that hydrolysis of GTP is also associated with the formation of linear oligomers of tubulin, which are precursors (prenuclei) in microtubule assembly. The hydrolysis of GTP on these linear oligomers inhibits the lateral association of GTP-tubuli... |
9199803 | Interpretation of multiple Q(0,0) bands in the absorption spectrum of Mg-mesoporphyrin embedded in horseradish peroxidase. | Mg-mesoporphyrin horseradish peroxidase (MgMP-HRP) and MgMP-HRP complexed with naphtohydroxamic acid (NHA) have been studied by fluorescence line narrowing (FLN) and pressure tuning spectral hole burning (SHB) techniques. In each sample, the low temperature absorption spectra show more than one transition in the origin... |
9199799 | Supramolecular self-assembly of d(TGG)4, synergistic effects of K+ and Mg2+. | Spectral evidence indicates that molar concentrations of K+ can induce aggregate formation in d(TGG)4. The 320-nm turbidity monitoring indicates that more than 1 M KCl is needed for the onset of aggregation to occur at 20 degrees C within the time span of 24 h. The kinetic profile is reminiscent of autocatalytic reacti... |
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