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7776368 | The origins and consequences of asymmetry in the chaperonin reaction cycle. | The binding of nucleotides and chaperonin-10 (cpn10) to the Escherichia coli chaperonin-60 (cpn60) and their effect upon the molecular symmetry has been examined both kinetically and at equilibrium. ATP binds tightly and is hydrolysed on only one heptameric ring of the cpn60 tetradecamer at a time, thus inducing asymme... |
7767464 | Resolution of the enantiomers of oxamniquine by capillary electrophoresis and high-performance liquid chromatography with cyclodextrins and heparin as chiral selectors. | The methods of separation of the enantiomers of the chiral drug oxamniquine are compared, between HPLC with either cyclodextrins and their related derivatives as chiral selectors in the mobile phase or immobilised in a chiral stationary phase (as Cyclobond I and II) and between capillary zone electrophoresis (CZE) wher... |
7766615 | Effects of oligosaccharide binding on glycogen debranching enzyme activity and conformation. | Glycogen debranching enzyme contains two catalytic activities (4-alpha-glucanotransferase and amylo-1,6-glucosidase) on its single polypeptide chain, and they are affected differently by the binding of oligosaccharides. Glucose, maltose, and maltotriose are competitive inhibitors of the amylo-1,6-glucosidase activity m... |
7766402 | Improved pertussis toxin production by Bordetella pertussis through adjusting the growth medium's ionic composition. | Ionic composition and total ionic concentration of the growth medium were important factors in limiting productivities in aerated reactors used for the production of pertussis toxin and other antigens by Bordetella pertussis. Salt concentration has opposing effects on cell growth of wild-type B. pertussis and specific ... |
7761443 | Disruption of the gene for hsp30, an alpha-crystallin-related heat shock protein of Neurospora crassa, causes defects in thermotolerance. | The alpha-crystallin-related heat shock proteins are produced by all eukaryotes, but the role of these proteins in thermoprotection remains unclear. To investigate the function of one of these proteins, we disrupted expression of the single-copy hsp30 gene of Neurospora crassa, using repeat-induced point mutagenesis, a... |
7761401 | Mimics of the binding sites of opioid receptors obtained by molecular imprinting of enkephalin and morphine. | Molecular imprinting of morphine and the endogenous neuropeptide [Leu5]enkephalin (Leu-enkephalin) in methacrylic acid-ethylene glycol dimethacrylate copolymers is described. Such molecular imprints possess the capacity to mimic the binding activity of opioid receptors. The recognition properties of the resultant impri... |
7759020 | beta-Cyclodextrin: 52-week toxicity studies in the rat and dog. | A 52-wk toxicity study by dietary administration was performed in Sprague-Dawley rats and in pure-bred beagle dogs with beta-cyclodextrin, a starch derivative that acts as a molecular inclusion agent. Doses of 0 (control), 12,500, 25,000 and 50,000 ppm were selected for the rat study, and 0 (control), 6200, 12,500 and ... |
7755585 | Expression of human all-trans-retinoic acid receptor beta and its ligand-binding domain in Escherichia coli. | all-trans-Retinoic acid, one of the hormonally active derivatives of vitamin A, occurs physiologically in plasma at a concentration below 10 nmol/l. The methods currently used for its quantification are based on HPLC, need about 1 ml of serum, are relatively laborious and thus not well suited for mass analysis. The aff... |
7755573 | Kinetics and thermodynamics of the binding of forskolin to the galactose-H+ transport protein, GalP, of Escherichia coli. | The binding of the transport inhibitor, forskolin, to the galactose-H+ symporter, GalP, of Escherichia coli was evaluated by equilibrium and time-resolved fluorescence measurements. A quench in protein fluorescence of 8-12% was observed upon the binding of forskolin. The overall dissociation constant (Kd) for forskolin... |
7755559 | Use of 'soluble lipids' for biochemical processes: linoleic acid-cyclodextrin inclusion complexes in aqueous solutions. | The equilibria of linoleic acid (LA)-cyclodextrin (CD) complexes were studied to investigate the behaviour of 'soluble lipids' in solution as a function of factors that typically affect biochemical processes, such as pH, temperature and CD structure. The above complexes are formed with a stoicheiometry of 1:2 in soluti... |
7752196 | Structure-activity relationships of 9-alkyladenine and ribose-modified adenosine derivatives at rat A3 adenosine receptors. | 9-Alkyladenine derivatives and ribose-modified N6-benzyladenosine derivatives were synthesized in an effort to identify selective ligands for the rat A3 adenosine receptor and leads for the development of antagonists. The derivatives contained structural features previously determined to be important for A3 selectivity... |
7752099 | Inhibition of human vascular smooth muscle cell migration and proliferation by beta-cyclodextrin tetradecasulfate. | Smooth muscle cell migration and proliferation are important regulatory processes in the development of intimal thickening after vascular injury. beta-cyclodextrin tetradecasulfate, an orally active synthetic heparin mimic, is effective in inhibiting rabbit aortic smooth muscle cell proliferation in vitro and in limiti... |
7751289 | Effector-mediated stimulation of ATPase activity by the sigma 54-dependent transcriptional activator FHLA from Escherichia coli. | The FHLA protein is the transcriptional regulator of the genes of the formate regulon from Escherichia coli. The protein shares homology with the sigma 54-dependent regulators of the NTRC family in the central and C-terminal domains but differs in possessing an extended N terminus lacking the aspartate residue which is... |
7751277 | Physical and functional S-layer reconstitution in Aeromonas salmonicida. | The various functions attributed to the S-layer of Aeromonas salmonicida have been previously identified by their conspicuous absence in S-layer-defective mutants. As a different approach to establish the multifunctional nature of this S-layer, we established methods for reconstitution of the S-layer of A. salmonicida.... |
7745399 | Inter-relation between "classic" motor neuron disease and frontotemporal dementia: neuropsychological and single photon emission computed tomography study. | The purpose of this study was to examine the possible association between "classic" motor neuron disease (cMND) and frontotemporal dementia (FTD), using neuropsychological evaluation and single photon emission computed tomography (SPECT). Psychological tests assessing language, perceptuospatial, memory, and "frontal lo... |
7744005 | Functional analysis of mutant neurotrophins deficient in low-affinity binding reveals a role for p75LNGFR in NT-4 signalling. | The neurotrophins mediate their effects through binding to two classes of receptors, a tyrosine kinase receptor, member of the Trk family, and the low-affinity neurotrophin receptor, p75LNGFR, of as yet undefined signalling capacity. The need for a two-component receptor system in neurotrophin signalling is still not u... |
7537851 | Endothelial interferon regulatory factor 1 cooperates with NF-kappa B as a transcriptional activator of vascular cell adhesion molecule 1. | Transcription of the vascular cell adhesion molecule 1 (VCAM-1) gene in endothelial cells is induced by lipopolysaccharide and the inflammatory cytokines interleukin-1 beta and tumor necrosis factor alpha (TNF-alpha). Previous studies have demonstrated that tandem binding sites for the inducible transcription factor NF... |
7738643 | Anti-chelate antibodies after intraperitoneal yttrium-90-labeled monoclonal antibody immunoconjugates for ovarian cancer therapy. | <h4>Unlabelled</h4>The development of stable chelating agents for metal isotopes (e.g., 90Y) such as CITC-DTPA, a benzyl-analog of DTPA, allowed us to evaluate the efficacy of 90Y-labeled HMFG1 MAb administered intraperitoneally in patients with ovarian cancer. Our previous studies of 90Y-HMFG1 antibody, however, showe... |
7730398 | Laminin mediates tissue-specific gene expression in mammary epithelia. | Tissue-specific gene expression in mammary epithelium is dependent on the extracellular matrix as well as hormones. There is good evidence that the basement membrane provides signals for regulating beta-casein expression, and that integrins are involved in this process. Here, we demonstrate that in the presence of lact... |
7730281 | Purification and characterization of the major surface array protein from the avirulent Bacillus anthracis Delta Sterne-1. | Many prokaryotic organisms possess surface layer (S-layer) proteins that are components of the outermost cell envelope. With immunogold labeling, it was demonstrated that the protein extractable antigen 1 (EA1) was localized on the outer surface and specifically to cell wall fragments from Bacillus anthracis which reta... |
7730254 | Single amino acid changes in domain II of Bacillus thuringiensis CryIAb delta-endotoxin affect irreversible binding to Manduca sexta midgut membrane vesicles. | Deletion of amino acid residues 370 to 375 (D2) and single alanine substitutions between residues 371 and 375 (FNIGI) of lepidopteran-active Bacillus thuringiensis CryIAb delta-endotoxin were constructed by site-directed mutagenesis techniques. All mutants, except that with the I-to-A change at position 373 (I373A), pr... |
7729924 | Molecular cloning of Proteus mirabilis uroepithelial cell adherence (uca) genes. | Proteus mirabilis bacteria are a common cause of hospital-acquired urinary tract infection. In a previous study, we described a P. mirabilis fimbrial protein, UCA, that adhered to human uroepithelial cells. Genes sufficient for expression of UCA adherence were cloned into Escherichia coli K-12. E. coli bacteria that co... |
7729051 | Direct measurement of high-density lipoprotein cholesterol in serum with polyethylene glycol-modified enzymes and sulfated alpha-cyclodextrin. | We have developed an automated method for measuring high-density lipoprotein (HDL)-cholesterol in serum without prior separation, using polyethylene glycol (PEG)-modified enzymes and sulfated alpha-cyclodextrin. When cholesterol esterase and cholesterol oxidase enzymes were modified with PEG, they showed selective cata... |
7722469 | Molecular behavior adapts to context: heparanase functions as an extracellular matrix-degrading enzyme or as a T cell adhesion molecule, depending on the local pH. | Migration of lymphocytes into inflammatory sites requires their adhesion to the vascular endothelium and subendothelial extracellular matrix (ECM). The ensuing penetration of the ECM is associated with the expression of ECM-degrading enzymes, such as endo-beta-D glucuronidase (heparanase), which cleaves heparan sulfate... |
7536748 | Plasticity in epithelial cell phenotype: modulation by expression of different cadherin cell adhesion molecules. | A primary function of cadherins is to regulate cell adhesion. Here, we demonstrate a broader function of cadherins in the differentiation of specialized epithelial cell phenotypes. In situ, the rat retinal pigment epithelium (RPE) forms cell-cell contacts within its monolayer, and at the apical membrane with the neural... |
7721948 | In vivo analysis of cadherin function in the mouse intestinal epithelium: essential roles in adhesion, maintenance of differentiation, and regulation of programmed cell death. | A model system is described for defining the physiologic functions of mammalian cadherins in vivo. 129/Sv embryonic stem (ES) cells, stably transfected with a dominant negative N-cadherin mutant (NCAD delta) under the control of a promoter that only functions in postmitotic enterocytes during their rapid, orderly, and ... |
7721864 | Mapping of network-forming, heparin-binding, and alpha 1 beta 1 integrin-recognition sites within the alpha-chain short arm of laminin-1. | Cell-interactive and architecture-forming functions are associated with the short arms of basement membrane laminin-1. To map and characterize these functions, we expressed recombinant mouse laminin-1 alpha-chain extending from the N terminus through one third of domain IIIb. This dumbbell-shaped glycoprotein (r alpha ... |
7721857 | Increased ubiquitin expression suppresses the cell cycle defect associated with the yeast ubiquitin conjugating enzyme, CDC34 (UBC3). Evidence for a noncovalent interaction between CDC34 and ubiquitin. | The yeast ubiquitin (Ub) conjugating enzyme CDC34 plays a crucial role in the progression of the cell cycle from the G1 to S phase. In an effort to identify proteins that interact with CDC34 we undertook a genetic screen to isolate genes whose increased expression suppressed the cell cycle defect associated with the cd... |
7721775 | Catalyzed thermal isomerization between previtamin D3 and vitamin D3 via beta-cyclodextrin complexation. | To examine the effect of microenvironments on previtamin D3<==>vitamin D3 isomerization, we have conducted kinetic studies of the reaction in an aqueous solution of beta-cyclodextrin. Our results showed that at 5 degrees C, the forward (k1) and reverse (k2) rate constants for previtamin D3<==>vitamin D3 isomerization w... |
7721714 | In vivo sulfhydryl modification of the ligand-binding site of Tsr, the Escherichia coli serine chemoreceptor. | The Escherichia coli chemoreceptor Tsr mediates an attractant response to serine. We substituted Cys for Thr-156, one of the residues involved in serine sensing. The mutant receptor Tsr-T156C retained serine- and repellent-sensing abilities. However, it lost serine-sensing ability when it was treated in vivo with sulfh... |
7721684 | Tn916 target DNA sequences bind the C-terminal domain of integrase protein with different affinities that correlate with transposon insertion frequency. | The conjugative transposon Tn916 inserts with widely different frequencies into a variety of target sites with related nucleotide sequences. The binding of chimeric proteins, consisting of maltose-binding protein fused to Tn916 integrase, to three different target sequences for Tn916 was examined by DNase I protection ... |
7718244 | Mapping the binding-site crevice of the dopamine D2 receptor by the substituted-cysteine accessibility method. | The binding site of the dopamine D2 receptor, like that of other homologous G protein-coupled receptors, is contained within a water-accessible crevice formed among its seven membrane-spanning segments. We have developed a method to map systematically all the residues forming the surface of this binding-site crevice, a... |
7536419 | Cyclodextrin glycosyltransferase may be the only starch-degrading enzyme in Bacillus macerans. | Cyclodextrin glycosyltransferase (CGTase) was released into the culture fluid by Bacillus macerans predominantly in the late stationary phase of growth and during autolysis in the presence of either glucose or starch as a carbon source. In both cases significant soluble intracellular enzyme activity could be observed i... |
7718160 | Characterization, subsite mapping and partial amino acid sequence of glucoamylase from the filamentous fungus Trichoderma reesei. | The pH optimum, temperature-dependence, thermal stability, substrate specificity and subsite affinities of the 66 kDa, pI 4.0 glucoamylase of the filamentous fungus Trichoderma reesei were determined. It had a pH optimum of 5.5 and a temperature optimum (5 min reaction time) of 70 degrees C with soluble starch as subst... |
7717985 | Expression of wild-type and mutated rabbit osteopontin in Escherichia coli, and their effects on adhesion and migration of P388D1 cells. | Recombinant wild-type rabbit osteopontin (rOP) and the protein with an aspartate-to-glutamate transposition induced by a point mutation in the rabbit OP cDNA within the Gly-Arg-Gly-Asp-Ser (GRGDS) sequence were expressed in Escherichia coli and purified to homogeneity. P388D1 cells bound rOP in a saturable manner. rOP ... |
7711051 | Characterization of bacterial reaction centers having mutations of aromatic residues in the binding site of the bacteriopheophytin intermediary electron carrier. | We report the initial characterization of a series of reaction centers (RCs) from the photosynthetic bacterium Rhodobacter capsulatus having single or double mutations of phenylalanines 97 and 121 on the L polypeptide. Substitution of these aromatic amino acids, which may interact with the photoactive bacteriopheophyti... |
7710936 | Effect of axial ligation and delivery system on the tumour-localising and -photosensitising properties of Ge(IV)-octabutoxy-phthalocyanines. | Four Ge(IV)-octabutoxy-phthalocyanines (GePcs) bearing two alkyl-type axial ligands were assayed for their pharmacokinetic properties and phototherapeutic efficiency in Balb/c mice bearing an intramuscularly transplanted MS-2 fibrosarcoma. The GePcs were i.v. injected at a dose of 0.35 mumol kg-1 body weight after inco... |
7706482 | Immune predispositions for cytomegalovirus retinitis in AIDS. The HNRC Group. | CMV retinitis develops in approximately 28-35% of all AIDS patients at later stages of disease, often leading to blindness. To determine whether the subset of AIDS patients who developed CMV retinitis (CMV-R) were immunologically predisposed, T cell proliferation responses to CMV were examined prospectively in an HIV i... |
7706477 | Tumor necrosis factor-alpha eliminates binding of NF-Y and an octamer-binding protein to the lipoprotein lipase promoter in 3T3-L1 adipocytes. | TNF alpha has been shown to reduce lipoprotein lipase (LPL) activity in adipose tissue. Regulation of LPL by TNF alpha occurs at the level of LPL gene transcription and posttranscriptionally. To elucidate further the transcriptional mechanism of TNF alpha inhibition of LPL gene transcription, transfection analysis was ... |
7535341 | Tumor dormancy and cell signaling. II. Antibody as an agonist in inducing dormancy of a B cell lymphoma in SCID mice. | Tumor dormancy can be induced in a murine B cell lymphoma (BCL1) by immunizing BALB/c mice with the tumor immunoglobulin (Ig) before tumor cell challenge. In this report, we have investigated the immunological and cellular mechanisms underlying the induction of dormancy. BCL1 tumor cells were injected into SCID mice pa... |
7899997 | Evolving concepts in the pathogenesis of postinjury multiple organ failure. | Early epidemiologic studies concluded that infection with systemic sepsis was the common pathway for the development of ARDS and eventual MOF. As a consequence, research investigation from 1977 to 1987 focused on later clinical events (e.g., immunosuppression, persistent hypercatabolism, and bacterial translocation). N... |
7891704 | Mechanisms for flexibility in DNA sequence recognition and VP16-induced complex formation by the Oct-1 POU domain. | DNA binding by the Oct-1 protein is directed by its POU domain, a bipartite DNA-binding domain made up of a POU-specific (POUS) domain and a POU-homeo (POUH) domain, two helix-turn-helix-containing DNA-binding modules that cooperate in DNA recognition. Although the best-characterized DNA target for Oct-1 binding is the... |
7891681 | Role of the Saccharomyces cerevisiae general regulatory factor CP1 in methionine biosynthetic gene transcription. | Saccharomyces cerevisiae general regulatory factor CP1 (encoded by the gene CEP1) is required for optimal chromosome segregation and methionine prototrophy. MET16-CYC1-lacZ reporter constructs were used to show that MET16 5'-flanking DNA contains a CP1-dependent upstream activation sequence (UAS). Activity of the UAS r... |
7890406 | Gonococcal opacity: lectin-like interactions between Opa proteins and lipooligosaccharide. | Previous evidence from our laboratory suggested that the tight intercellular adhesions between the outer membranes of gonococci displaying the opacity colony phenotype occurred because Opa proteins expressed on one gonococcus adhered to the lipooligosaccharide (LOS) of the opposing bacterium (M.S. Blake, p. 51-66, in G... |
7890381 | Differential susceptibility of yeast and hyphal forms of Candida albicans to proteolytic activity of macrophages. | The dimorphic transition of Candida albicans from the yeast (Y-Candida) to the hyphal (H-Candida) form is a complex event whose relevance in fungal pathogenicity is still poorly understood. Using a cloned macrophage (M phi) cell line (ANA-1), we have previously shown that a M phi can discriminate between the two fungal... |
7890377 | Biological activity of toxic shock syndrome toxin 1 and a site-directed mutant, H135A, in a lipopolysaccharide-potentiated mouse lethality model. | A recombinant of toxic shock syndrome toxin 1 (TSST-1) which contains a single histidine-to-alanine mutation at residue 135 (H135A) was analyzed for toxicity and vaccine potential in a lipopolysaccharide (LPS)-potentiated mouse lethality model. The 50% lethal dose (LD50) of TSST-1 in BALB/c mice was 47.2 micrograms/kg,... |
7884928 | Identification of two separable modules in the duck hepatitis B virus core protein. | Hepadnavirus replication requires the concerted action of the polymerase and core proteins to ensure packaging of the RNA pregenome and DNA maturation. The arginine-rich C terminus of the core protein plays an essential role in both of these steps while being dispensable for nucleocapsid formation. In an attempt to ide... |
7884896 | Tyrosine phosphorylation of measles virus nucleocapsid protein in persistently infected neuroblastoma cells. | Subacute sclerosing panencephalitis is a slowly progressing fatal human disease of the central nervous system which is a delayed sequel of measles virus (MV) infection. A typical pathological feature of this disease is the presence of viral ribonucleocapsid structures in the form of inclusion bodies and the absence of ... |
7884891 | The JC virus minimal core promoter is glial cell specific in vivo. | The glial cell specificity of the human papovavirus JC (JCV), an etiologic agent for progressive multifocal leukoencephalopathy, is thought to be due to the presence of both positive and negative regulatory elements upstream of the TATA region within the JCV promoter. Here we report that the JCV minimal core promoter, ... |
7884882 | Sequence requirements for encapsidation of deletion mutants and chimeras of human immunodeficiency virus type 1 Gag precursor into retrovirus-like particles. | Interacting domains in human immunodeficiency virus type 1 (HIV-1) Gag precursor (Pr55gag) expressed in recombinant baculovirus-infected cells were investigated by three different methods: (i) trans rescue and coencapsidation of C-terminal deletion (amber) Gag mutants and Gag chimeras into retrovirus-like particles in ... |
7884856 | RNA secondary structure and binding sites for gag gene products in the 5' packaging signal of human immunodeficiency virus type 1. | The selective encapsidation of retroviral RNA requires sequences in the Gag protein, as well as a cis-acting RNA packaging signal (psi site) near the 5' end of the genomic transcript. Gag protein of human immunodeficiency virus type 1 (HIV-1) has recently been found to bind specifically to the HIV-1 psi element in vitr... |
7884846 | Specific binding of host cellular proteins to multiple sites within the 3' end of mouse hepatitis virus genomic RNA. | The initial step in mouse hepatitis virus (MHV) RNA replication is the synthesis of negative-strand RNA from a positive-strand genomic RNA template. Our approach to begin studying MHV RNA replication is to identify the cis-acting signals for RNA synthesis and the proteins which recognize these signals at the 3' end of ... |
25125793 | Effects of Discrete Protein-Surface Interactions in Scanning Force Microscopy Adhesion Force Measurements. | The potential for measuring specific molecular recognition forces between probe-bound ligands and surface-bound proteins using a scanning force microscope (SFM) has recently gained much attention. Generally, observed discontinuities in the SFM force-displacement curves are attributed to the breaking of discrete, specif... |
17814788 | Spin crossover in a catenane supramolecular system. | The compound [Fe(tvp)(2)(NCS)(2)] . CH(3)OH, where tvp is 1,2-di-(4-pyridyl)-ethylene, has been synthesized and characterized by x-ray single-crystal diffraction. It consists of two perpendicular, two-dimensional networks organized in parallel stacks of sheets made up of edge-shared [Fe(II)](4) rhombuses. The fully int... |
16534999 | Purification and Properties of Extracellular Amylase from the Hyperthermophilic Archaeon Thermococcus profundus DT5432. | A hyperthermophilic archaeon, Thermococcus profundus DT5432, produced extracellular thermostable amylases. One of the amylases (amylase S) was purified to homogeneity by ammonium sulfate precipitation, DEAE-Toyopearl chromatography, and gel filtration on Superdex 200HR. The molecular weight of the enzyme was estimated ... |
16534996 | Analysis of factors affecting the accuracy, reproducibility, and interpretation of microbial community carbon source utilization patterns. | We determined factors that affect responses of bacterial isolates and model bacterial communities to the 95 carbon substrates in Biolog microtiter plates. For isolates and communities of three to six bacterial strains, substrate oxidation rates were typically nonlinear and were delayed by dilution of the inoculum. When... |
9696568 | Effect of temperature on separation of estradiol stereoisomers and equilin by liquid chromatography using mobile phases modified with beta-cyclodextrin. | The unusual temperature effect on the retention of 17 alpha-estradiol, 17 beta-estradiol and equilin in reversed-phase liquid chromatography has been observed. Capacity factors (k') of the steroids were measured using mobile phase with different concentrations of beta-cyclodextrin (from 0 to 16 mM) in a fixed mobile ph... |
9696567 | Interaction of taxol and other anticancer drugs with alpha-cyclodextrin. | The interaction between 23 anticancer drugs and alpha-cyclodextrin (alpha-CD) was studied by reversed-phase charge-transfer thin-layer chromatography and the relative strength of interaction was calculated. As alpha-CD has smaller cavity than beta- and tau-CD it interacted only with 10 anticancer drugs proving the rela... |
9696566 | Use of principal component analysis for the evaluation of the retention behaviour of monoamine oxidase inhibitory drugs on beta-cyclodextrin column. | The retention of 17 monoamine oxidase inhibitory drugs (proparlgylamine derivatives) were determined on a beta-cyclodextrin polymer (beta CDP)-coated silica column using ethanol-0.05 M K2HPO4 (6:4 v/v) as the eluent. The relative strength of interaction between the drugs and a water soluble beta-cyclodextrin polymer wa... |
9383422 | Engineering of a synthetic receptor to alter peptide binding selectivity. | <h4>Background</h4>Molecular recognition processes are ubiquitous in nature: substrate binding by enzymes, antigen recognition by antibodies, and hormone activation of receptors provide three classic examples. To better understand these large systems it is valuable to study smaller, well defined host molecules. Previou... |
7588518 | Enantiomeric separation of amino acids using micellar electrokinetic chromatography after pre-column derivatization with the chiral reagent 1-(9-fluorenyl)-ethyl chloroformate. | Direct enantiomeric separations of some racemic amino acids derivatized with 9-fluorenylmethyl chloroformate were obtained using cyclodextrin-modified micellar electrokinetic chromatography (CD/MEKC) with a buffer made up of 5 mM sodium borate (pH 9.2), 150 mM sodium dodecyl sulfate (SDS) and 40 mM gamma-CD. Alternativ... |
7567922 | Protein docking for low-resolution structures. | A typical problem for a docking procedure is how to match two molecules with known 3-D structure so as to predict the configuration of their complex. A very serious obstacle to docking is an inherent inaccuracy in the 3-D structures of the molecules. In general, existing molecular recognition techniques are not designe... |
7640672 | Biological and serological characterization of Campylobacter jejuni lipopolysaccharides with deviating core and lipid A structures. | Lipopolysaccharides from Campylobacter jejuni were tested for their ability to induce toxic lethality in galactosamine-sensitized mice, pyrogenicity in rabbits and tumour necrosis factor (TNF) secretion from mouse peritoneal macrophages. Compared with those of Salmonella LPS, lethal toxicity was 50% lower, pyrogenicity... |
7640154 | Absorption of clonazepam after intranasal and buccal administration. | Serum concentrations of clonazepam after intranasal, buccal and intravenous administration were compared in a cross-over study in seven healthy male volunteers. Each subject received a 1.0 mg dose of clonazepam intranasally and buccally and 0.5 mg intravenously. A Cmax of 6.3 +/- 1.0 ng ml-1 (mean; +/- s.d.) was measur... |
7624899 | Monoethylglycinexylidide as an early predictor of posttraumatic multiple organ failure. | The prognostic value of a dynamic liver-function test, based on the hepatic conversion of lidocaine to monoethylglycinexylidide (MEGX), in predicting multiple organ failure (MOF) was prospectively investigated in 28 critically ill patients after multiple trauma. The MEGX test and conventional static liver tests (biliru... |
7621403 | Virus receptors: implications for pathogenesis and the design of antiviral agents. | A virus initiates infection by attaching to its specific receptor on the surface of a susceptible host cell. This prepares the way for the virus to enter the cell. Consequently, the expression of the receptor on specific cells and tissues of the host is a major determinant of the route of entry of the virus into the ho... |
7542558 | Antiviral therapy for human immunodeficiency virus infections. | Depending on the stage of their intervention with the viral replicative cycle, human immunodeficiency virus inhibitors could be divided into the following groups: (i) adsorption inhibitors (i.e., CD4 constructs, polysulfates, polysulfonates, polycarboxylates, and polyoxometalates), (ii) fusion inhibitors (i.e., plant l... |
7619788 | The application of stereolithography to the fabrication of accurate molecular models. | The process of stereolithography, which automatically fabricates plastic models from designs created in certain computer-aided design programs, has been applied to the production of accurate plastic molecular models. Atomic coordinates obtained from quantum mechanical calculations and from neutron diffraction data were... |
7613869 | The avian eye lens protein delta-crystallin shows a novel packing arrangement of tetramers in a supramolecular helix. | <h4>Background</h4>Little is known of the intermolecular organization of crystallins in the protein-packed eye lens. The tetrameric structure of the 200,000 Da avian delta-crystallin, which is closely related to the enzyme argininosuccinate lyase and is characteristic of the accommodating, soft lens of birds, has recen... |
7613469 | Secondary and tertiary structure of the A-state of cytochrome c from resonance Raman spectroscopy. | Ferricytochrome c can be converted to the partially folded A-state at pH 2.2 in the presence of 1.5 M NaCl. The structure of the A-state has been studied in comparison with the native and unfolded states, using resonance Raman spectroscopy with visible and ultraviolet excitation wavelengths. Spectra obtained with 200 n... |
7613463 | Proline cis-trans isomerization in staphylococcal nuclease: multi-substrate free energy perturbation calculations. | Staphylococcal nuclease A exists in two folded forms that differ in the isomerization state of the Lys 116-Pro 117 peptide bond. The dominant form (90% occupancy) adopts a cis peptide bond, which is observed in the crystal structure. NMR studies show that the relatively small difference in free energy between the cis a... |
7613460 | Competing interactions contributing to alpha-helical stability in aqueous solution. | The stability of a 15-residue peptide has been investigated using CD spectroscopy and molecular simulation techniques. The sequence of the peptide was designed to include key features that are known to stabilize alpha-helices, including ion pairs, helix dipole capping, peptide bond capping, and aromatic interactions. T... |
7609604 | Purification and properties of an extracellular lipase from the fungus Botrytis cinerea. | An extracellular lipase (EC 3.1.1.3) from the fungus Botrytis cinerea has been purified to homogeneity and characterized. The purification included ammonium sulfate fractionation and sequential column chromatography. The purification of the preparation was 31-fold and recovery yield was 21%. The purified enzyme was ass... |
7609600 | Thermotropic behavior of stratum corneum lipids containing a pseudo-ceramide. | The mechanism of the self-assembly of the lamellar structure of natural stratum corneum lipids (SCL) has been a subject of considerable interest. We have examined this question by using a synthetic pseudo-ceramide (sphingolipid E, SLE) which was analogous to the naturally occurring ceramide type 2. The thermotropic pro... |
7596992 | Effects of inclusion complexation on the transepithelial transport of a lipophilic substance in vitro. | Poor oral bioavailability of three experimental compounds, 1-III, observed in animals has been attributed to the low intrinsic solubility. To enhance their GI absorption, we attempted to increase the solubility of these compounds with hydroxypropyl beta-cyclodextrin (HPB)4 and gamma-cyclodextrin (HPG). Compound I showe... |
7596987 | Ocular absorption and irritation of pilocarpine prodrug is modified with buffer, polymer, and cyclodextrin in the eyedrop. | The influence of buffer, viscosity and cyclodextrin on the ocular absorption and irritation of a pilocarpine prodrug, O,O'-dipropionyl-(1,4-xylylene) bispilocarpic acid diester, was studied in albino rabbits. The prodrug solutions, equivalent to 0.5% pilocarpine, were prepared in 0, 10, 20, 50, or 75 mM citrate buffer ... |
7787042 | Mesoscopic gel at low agarose concentration in water: a dynamic light scattering study. | Previous work in our laboratory has shown that at very low agarose concentration in water gelation still occurs within mutually disconnected, high concentration regions generated by spinodal demixing. The freely diffusing particles obtained in these conditions are studied in the present work by depolarized dynamic ligh... |
7787040 | Three-dimensional reconstruction of fibrin clot networks from stereoscopic intermediate voltage electron microscope images and analysis of branching. | Fibrin polymerizes to produce branching fibers forming a three-dimensional network, which has been difficult to visualize by conventional microscopy. Three-dimensional images of whole clots at high resolution were obtained from stereo-pair intermediate-voltage electron micrographs. Computer software was developed to pr... |
7540429 | Modeling success and failure of Langmuir-Blodgett transfer of phospholipid bilayers to silicon dioxide. | Formation of planar phospholipid bilayers on solid and porous substrates by Langmuir-Blodgett transfer of monolayers from the air-water interface could be of much greater utility if the process were not irreproducible and poorly understood. To that end the energetics of transferring two phospholipid monolayers to a hyd... |
7540427 | Charge selectivity of the designed uncharged peptide ion channel Ac-(LSSLLSL)3-CONH2. | Charge selectivity in ion channel proteins is not fully understood. We have studied charge selectivity in a simple model system without charged groups, in which an amphiphilic helical peptide, Ac-(Leu-Ser-Ser-Leu-Leu-Ser-Leu)3-CONH2, forms ion channels across an uncharged phospholipid membrane. We find these channels t... |
7787020 | Confinement as a determinant of macromolecular structure and reactivity. II. Effects of weakly attractive interactions between confined macrosolutes and confining structures. | The effect of weak, nonspecific interaction between molecules confined within restricted elements of volume ("pores") and the boundary surfaces of the pore, upon the reactivity and physical state of the confined molecules, is explored by means of simple models. A confined molecule is represented by a rectangular parall... |
7787019 | Seven-helix bundles: molecular modeling via restrained molecular dynamics. | Simulated annealing via restrained molecular dynamics (SA/MD) has been used to model compact bundles of seven approximately (anti)parallel alpha-helices. Seven such helix bundles occur, e.g., in bacteriorhodopsin, in rhodopsin, and in the channel-forming N-terminal domain of Bacillus thuringiensis delta-endotoxin. Two ... |
7787013 | Cell fission and formation of mini cell bodies by high frequency alternating electric field. | We report the use of high frequency alternating electric fields (AC) to induce deformation of sea urchin eggs, leading to budding of membrane vesicles or fission of cells. Several mini cell bodies can be prepared from a single egg by carefully manipulating the frequency and amplitude of the AC field and the ratio betwe... |
7779980 | [Supramolecular organization of erythrocyte glycolysis. II. Viscosity of the cytoplasm]. | Based on the molecular composition of the human erythrocyte cytoplasm, the contribution of each of the components (proteins, metabolites, electrolytes) in the overall values of the cytoplasm viscosity has been estimated. The viscosity of the human erythrocyte cytoplasm may be thought of as being determined by the prote... |
7779979 | [Supramolecular organization of erythrocyte glycolysis. I. Composition of the cytoplasm]. | The problems of supramolecular organization of glycolysis in human erythrocytes, molecular composition of the cytoplasm and putative forms of glycolysis organization have been reviewed. A hypothetical complex of glycolytic enzymes (metabolon) is discussed. Based on the molecular composition and experimental evidence, t... |
7774859 | [Inhibitory effects of prostaglandin E1.alpha-cyclodextrin (PGE1.CD) on dimethylnitrosamine-induced acute liver damage in rats]. | The effects of PGE1.CD on dimethylnitrosamine (DMN)-induced acute liver damage with intravascular coagulation in rats were biochemically and histopathologically investigated. PGE1.CD was administered i.v. from 30 min before to 24 hr after DMN-intoxication (pretreatment) and from 30 min after or from 4 hr after to 24 hr... |
7767838 | Methylated beta-cyclodextrins are able to improve the nasal absorption of salmon calcitonin. | The absorption enhancing effect of methylated beta-cyclodextrins on the nasal absorption of salmon calcitonin (sCT) was studied in rats and rabbits. The nasal absorption of sCT following administration without additives was low in both species. The absorption in rats could be largely improved by coadministration of cyc... |
7749627 | Haptoglobin in Carnivora: a unique molecular structure in bear, cat and dog haptoglobins. | Haptoglobin (Hp), a hemoglobin-binding protein in plasma, consists of alpha and beta subunits and has a tetra-chain arrangement (beta-alpha-alpha-beta) connected by disulfide bridges in most mammals so far examined. Dog Hp has been reported to be unique compared with other Hps in respect that (1) the two alpha beta uni... |
7747949 | Cyclodextrin formation by the thermostable alpha-amylase of Thermoanaerobacterium thermosulfurigenes EM1 and reclassification of the enzyme as a cyclodextrin glycosyltransferase. | Extensive characterization of the thermostable alpha-amylase of Clostridium thermosulfurogenes EM1, recently reclassified as Thermoanaerobacterium thermosulfurigenes, clearly demonstrated that the enzyme is a cyclodextrin glycosyltransferase (CGTase). Product analysis after incubation of the enzyme with starch revealed... |
7739896 | Tyrosine 27 of the specificity polypeptide of EcoKI can be UV crosslinked to a bromodeoxyuridine-substituted DNA target sequence. | The specificity (S) subunit of the restriction enzyme EcoKI imparts specificity for the sequence AAC(N6)GTGC. Substitution of thymine with bromodeoxyuridine in a 25 bp DNA duplex containing this sequence stimulated UV light-induced covalent crosslinking to the S subunit. Crosslinking occurred only at the residue comple... |
7739044 | Three-dimensional structure of a lipoyl domain from the dihydrolipoyl acetyltransferase component of the pyruvate dehydrogenase multienzyme complex of Escherichia coli. | The structure of a lipoyl domain from the pyruvate dehydrogenase multienzyme complex of Escherichia coli has been determined by means of nuclear magnetic resonance spectroscopy. A total of 549 nuclear Overhauser effect distance restraints, 52 phi torsion angle restraints and 16 slowly exchanging amide protons were empl... |
7739007 | Antitumor activity of 9(R)-dihydrotaxane analogs. | A novel reduced taxane, 13-acetyl-9(R)-dihydrobaccatin III (1) has been isolated from Taxus canadensis. The selective C-13 deacetylation of this isolate has allowed for the preparation of a wide variety of 9(R)-dihydrotaxane analogs. In general, this series has shown greater stability and water solubility than the 9-ca... |
7733901 | Evidence of a defined spatial arrangement of hyaluronate in the central filament of cartilage proteoglycan aggregates. | Aggregates of proteoglycans from the Swarm rat chondrosarcoma reassembled in vitro have been studied by rotary-shadowing electron microscopy, and shown to be similar to native structures that have never been dissociated [Mörgelin, Engel, Heinegård and Paulsson (1992) J. Biol. Chem. 267, 14275-14284]. A hyaluronate with... |
7733890 | Determination of the structure of an N-substituted protoporphyrin isolated from the livers of griseofulvin-fed mice. | Feeding mice with griseofulvin, a widely used anti-fungal agent which induces protoporphyria as a side-effect, leads to the formation in the liver of two green pigments which have been shown to be porphyrin adducts. In this work, the major porphyrin adduct isolated from the livers of griseofulvin-fed mice has been char... |
7732031 | Bipartite function of a small RNA hairpin in transcription antitermination in bacteriophage lambda. | Transcription of downstream genes in the early operons of phage lambda requires a promoter-proximal element known as nut. This site acts in cis in the form of RNA to assemble a transcription antitermination complex which is composed of lambda N protein and at least four host factors. The nut-site RNA contains a small s... |
7727505 | Purification and characterization of an alkaline amylopullulanase with both alpha-1,4 and alpha-1,6 hydrolytic activity from alkalophilic Bacillus sp. KSM-1378. | The novel alkaline amylopullulanase produced by alkalophilic Bacillus sp. KSM-1378 was purified to an electrophoretically homogeneous state from culture medium. The purified enzyme was a glycoprotein with an apparent molecular mass of about 210 kDa and an isoelectric point of pH 4.8. The N-terminal amino acid sequence ... |
7724608 | The glucocorticoid receptor type II complex is a target of the HIV-1 vpr gene product. | The vpr gene of human immunodeficiency virus type 1 (HIV-1) encodes a 15-kDa virion-associated protein that functions as a regulator of cellular processes linked to the HIV life cycle. We report the interaction of a 41-kDa cytosolic viral protein R interacting protein 1 (Rip-1) with Vpr in vitro. Rip-1 displays a wide ... |
7724602 | A constant radius of curvature model for the organization of DNA in toroidal condensates. | Toroidal DNA condensates have received considerable attention for their possible relationship to the packaging of DNA in viruses and in general as a model of ordered DNA condensation. A spool-like model has primarily been supported for DNA organization within toroids. However, our observations suggest that the actual o... |
7724581 | Heterogeneity in molecular recognition by restriction endonucleases: osmotic and hydrostatic pressure effects on BamHI, Pvu II, and EcoRV specificity. | The cleavage specificity of the Pvu II and BamHI restriction endonucleases is found to be dramatically reduced at elevated osmotic pressure. Relaxation in specificity of these otherwise highly accurate and specific enzymes, previously termed "star activity," is uniquely correlated with osmotic pressure between 0 and 10... |
7724554 | A sampling problem in molecular dynamics simulations of macromolecules. | Correlations in low-frequency atomic displacements predicted by molecular dynamics simulations on the order of 1 ns are undersampled for the time scales currently accessible by the technique. This is shown with three different representations of the fluctuations in a macromolecule: the reciprocal space of crystallograp... |
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