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Sample records for acid terminated alkanethiol

  1. Improvements in the characterization of the crystalline structure of acid-terminated alkanethiol self-assembled monolayers on Au(111).

    PubMed

    Mendoza, Sandra M; Arfaoui, Imad; Zanarini, Simone; Paolucci, Francesco; Rudolf, Petra

    2007-01-16

    We report a study of acid-terminated self-assembled monolayers of alkanethiols of different length, 11-mercaptoundecanoic acid (11-MUA) and 16-mercaptohexadecanoic acid (16-MHDA), on Au(111). Scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and contact angle techniques were used for characterization, and the results were compared with those obtained from n-alkanethiols of similar chain length, providing a detailed description of the two-dimensional crystalline structure. Molecular resolution STM images show that 11-MUA forms a dense-packed monolayer arranged in a (square root 3 x square root 3)R30 degrees structure with a c(2 x 4) superlattice, where the simple hexagonal phase, the c(2 x 4) superlattice, and nonordered areas coexist. 16-MHDA assembles in a uniform monolayer with similar morphology to that of 11-MUA, but molecular resolution could not be reached in STM due to both the hydrophilicity of the acid groups and the poor conductivity of the thick monolayer. Nevertheless, the monolayer thicknesses estimated by XPS and electrochemistry and the highly blocking character of the film observed by electrochemistry as well as the low water contact angle are consistent with 16-MHDA molecules forming a compact monolayer on the Au(111) substrate with fully extended alkyl chains and acid groups pointing away from the surface. The results obtained for 16-MHDA were reproducible under different preparation conditions such as the addition or omission of acetic acid to the ethanolic solution. Contrary to other reports, we demonstrate that ordered acid-terminated self-assembled monolayers are obtained with the same preparation conditions as those of the methyl-terminated ones, without any additional treatment.

  2. Coadsorption of ferrocene-terminated and unsubstituted alkanethiols on gold: Electroactive self-assembled monolayers

    SciTech Connect

    Chidsey, C.E.D.; Bertozzi, C.R.; Putvinski, T.M.; Mujsce, A.M. )

    1990-05-23

    Self-assembled monolayers provide an ideal system for disentangling the fundamental events in interfacial electron transfer. Coadsorption of ferrocene-terminated alkanethiols with unsubstituted n-alkanethiols on evaporated gold films yields stable, electroactive self-assembled monolayers. Monolayers containing low concentrations of alkanethiols linked to ferrocene by a polar ester group (FcCO{sub 2}(CH{sub 2}){sub n}SH, Fc = ({eta}{sup 5}-C{sub 5}H{sub 5})Fe({eta}{sup 5}-C{sub 5}H{sub 4})) show thermodynamically ideal surface electrochemistry in 1 M HClO{sub 4}, indicating the ferrocene groups to be homogeneous and noninteracting. Higher surface concentrations or use of alkanethiols linked directly to the nonpolar ferrocene group (Fc(CH{sub 2}){sub n}SH) lead to broadened electrochemical features, indicating interactions among ferrocene groups or inhomogeneous sites. Longer chain lengths and lower ferrocene surface concentrations result in slower electron-transfer kinetics with the ferrocene groups. A fraction of the thiols in a monolayer exchange with thiols in an ethanol solution, but much of the monolayer remains unequilibrated after 10 days.

  3. Omega-Terminated Alkanethiolate Monolayers on Surfaces of Copper, Silver and Gold Have Similar Wettabilities

    DTIC Science & Technology

    1991-12-01

    metal cxides and form oriented, oleophobic monolayers,25 0-hydroxy- and W-amino-alkanoic acids adsorb and form poorly organized films that are not wet...gold. Experinental Materials . 1l-Bromo-undecyl t-butyldimethylsilyl ether and most alkanethiols were available from pcrevious studies;6, 2 1, 4 8 ctn...er materials were obtained from Aldrich and used as received unless Specified. Octadecanethiol was distilled under reduced pressure prior to use

  4. Preparation of Partially Poisoned Alkanethiolate-Capped Platinum Nanoparticles for Hydrogenation of Activated Terminal Alkynes.

    PubMed

    San, Khin Aye; Chen, Vivian; Shon, Young-Seok

    2017-03-22

    Stable and isolable alkanethiolate-stabilized Pt nanoparticles (PtNP) were synthesized using the two-phase thiosulfate method with sodium S-alkylthiosulfate as ligand precursor. The mechanistic formation of octanethiolate-capped PtNP (Pt-SC8) from both sodium S-octylthiosulfate and 1-octanethiol ligands was investigated by using (1)H NMR and UV-vis spectroscopies, which revealed the formation of different Pt complexes as the reaction intermediates. The synthesis using S-octylthiosulfate ligand precursor produced Pt-SC8 in higher yields than that using 1-octanethiol ligand. The obtained nanoparticles were characterized by (1)H NMR, UV-vis spectroscopy, infrared spectroscopy (IR), thermogravimetric analysis, and transmission electron microscopy (TEM). The results obtained from (1)H NMR, IR, and UV-vis spectroscopy were consistent with the formation of stable and pure alkanethiolate-capped PtNP. TEM images of PtNP confirmed their small average core size (∼1.5 nm) and high monodispersity. The partially poisoned PtNP with thiolate monolayer ligands were further investigated for the hydrogenation of various alkynes to understand the organic ligands-induced geometric and electronic surface properties of colloidal Pt nanoparticle catalysts. The high catalytic activity of activated terminal alkynes, but the significantly low activity of internal alkynes and unactivated terminal alkynes, were observed under the mild reaction conditions (room temperature and atmospheric pressure). These results indicated that the presence of alkanethiolate ligands could decrease the coordination activity of PtNP surface especially for the bulkier and unactivated substrates.

  5. Bacterial adhesion to hydroxyl- and methyl-terminated alkanethiol self-assembled monolayers.

    PubMed Central

    Wiencek, K M; Fletcher, M

    1995-01-01

    The attachment of bacteria to solid surfaces is influenced by substratum chemistry, but to determine the mechanistic basis of this relationship, homogeneous, well-defined substrata are required. Self-assembled monolayers (SAMs) were constructed from alkanethiols to produce a range of substrata with different exposed functional groups, i.e., methyl and hydroxyl groups and a series of mixtures of the two. Percentages of hydroxyl groups in the SAMs and substratum wettability were measured by X-ray photoelectron spectroscopy and contact angles of water and hexadecane, respectively. SAMs exhibited various substratum compositions and wettabilities, ranging from hydrophilic, hydroxyl-terminated monolayers to hydrophobic, methyl-terminated monolayers. The kinetics of attachment of an estuarine bacterium to these surfaces in a laminar flow chamber were measured over periods of 120 min. The initial rate of net adhesion, the number of cells attached after 120 min, the percentage of attached cells that adsorbed or desorbed between successive measurements, and the residence times of attached cells were quantified by phase-contrast microscopy and digital image processing. The greatest numbers of attached cells occurred on hydrophobic surfaces, because (i) the initial rates of adhesion and the mean numbers of cells that attached after 120 min increased with the methyl content of the SAM and the contact angle of water and (ii) the percentage of cells that desorbed between successive measurements (ca. 2 min) decreased with increasing substratum hydrophobicity. With all surfaces, 60 to 80% of the cells that desorbed during the 120-min exposure period had residence times of less than 10 min, suggesting that establishment of firm adhesion occurred quickly on all of the test surfaces. PMID:7721687

  6. Rectifications in organic single-molecule diodes alkanethiolate-terminated heterocyclics

    NASA Astrophysics Data System (ADS)

    An, Yipeng; Zhang, Mengjun; Wang, Tianxing; Wang, Guangtao; Fu, Zhaoming

    2016-02-01

    Based on the non-equilibrium Green's function formalism combined with the ab initio density functional theory, we investigate the rectifying behaviors of the organic single-molecule S(CH2)11-terminated with a variety of heterocyclics (i.e., BIPY, PHE, PHEPY, and PYR) coupled with two semi-infinite Au electrodes. Our quantum transport calculation results show that the BIPY and PHE nanojunctions show the high-efficiency rectifying effects. While, differently, the current-voltage (I-V) curves of PHEPY and PYR nanojunctions display the insulating and linear characters, respectively. The corresponding electronic transport mechanisms are analyzed in detail. Our calculation results demonstrate that these investigated organic single-molecule nanojunctions have the potential applications in rectifiers and molecular wires.

  7. Tribology of monolayer films: comparison between n-alkanethiols on gold and n-alkyl trichlorosilanes on silicon.

    PubMed

    Booth, Brandon D; Vilt, Steven G; McCabe, Clare; Jennings, G Kane

    2009-09-01

    This Article presents a quantitative comparison of the frictional performance for monolayers derived from n-alkanethiolates on gold and n-alkyl trichlorosilanes on silicon. Monolayers were characterized by pin-on-disk tribometry, contact angle analysis, ellipsometry, and electrochemical impedance spectroscopy (EIS). Pin-on-disk microtribometry provided frictional analysis at applied normal loads from 10 to 1000 mN at a speed of 0.1 mm/s. At low loads (10 mN), methyl-terminated n-alkanethiolate self-assembled monolayers (SAMs) exhibited a 3-fold improvement in coefficient of friction over SAMs with hydroxyl- or carboxylic-acid-terminated surfaces. For monolayers prepared from both n-alkanethiols on gold and n-alkyl trichlorosilanes on silicon, a critical chain length of at least eight carbons is required for beneficial tribological performance at an applied load of 9.8 mN. Evidence for disruption of chemisorbed alkanethiolate SAMs with chain lengths n alkanethiolate and silane monolayers shows that monolayers prepared from n-octadecyl dimethylchlorosilane and n-octadecyl trichlorosilane withstood normal loads at least 30 times larger than those that damaged octadecanethiolate SAMs. Collectively, our results show that the tribological properties of monolayer films are dependent on their internal stabilities, which are influenced by cohesive chain interactions (van der Waals) and the adsorbate-substrate bond.

  8. Characterization of hydroxyphenol-terminated alkanethiol self-assembled monolayers: interactions with phosphates by chemical force spectrometry.

    PubMed

    Azmi, Alyza A; Ebralidze, Iraklii I; Dickson, Steven E; Horton, J Hugh

    2013-03-01

    Tannins and humic substances, commonly referred to as natural organic matter (NOM), constitute an important component of natural water and soil systems. These species contain numerous hydroxyl and carboxyl functional groups whose reactivity is strongly dependent on both the quantity and location of these moieties on the aromatic ring. In the present study, self-assembled monolayers (SAMs) of 4-(12-mercaptododecyl)benzene-1,2-diol (o-hydroxyphenol-terminated); 5-(12-mercaptododecyl)benzene-1,3-diol (m-hydroxyphenol-terminated); bis(11-thioundecyl) hydrogen phosphate (monoprotic phosphate); and 11-thioundecyl dihydrogen phosphate (diprotic phosphate) were prepared and characterized using X-ray photoelectron spectroscopy (XPS), attenuated total reflectance infrared spectroscopy (ATR-IR), and water contact angle measurements. The interactions between phenolic groups with phosphates were examined as a function of pH using the chemical force spectrometry (CFS) technique. The observations are discussed in the context of hydrogen bonding and electrostatic repulsion interaction between corresponding species. Adhesion force profiles of hydroxyphenol isomers interacting with monoprotic phosphate are dominated by ionic H-bonding; however the strength of o-hydroxyphenol interactions is significantly higher. The difference in location of hydroxyl groups on the interface also results in significantly different force-distance profiles for the isomeric hydroxyphenols when interacting with diprotic phosphate.

  9. Influence of Self-Assembled Alkanethiol Monolayers on Stochastic Amperometric On-Chip Detection of Silver Nanoparticles.

    PubMed

    Krause, Kay J; Adly, Nouran; Yakushenko, Alexey; Schnitker, Jan; Mayer, Dirk; Offenhäusser, Andreas; Wolfrum, Bernhard

    2016-04-05

    We investigate the influence of self-assembled alkanethiol monolayers at the surface of platinum microelectrode arrays on the stochastic amperometric detection of citrate-stabilized silver nanoparticles in aqueous solutions. The measurements were performed using a microelectrode array featuring 64 individually addressable electrodes that are recorded in parallel with a sampling rate of 10 kHz for each channel. We show that both the functional end group and the total length of the alkanethiol influence the charge transfer. Three different terminal groups, an amino, a hydroxyl, and a carboxyl, were investigated using two different molecule lengths of 6 and 11 carbon atoms. Finally, we show that a monolayer of alkanethiols with a length of 11 carbon atoms and a carboxyl terminal group can efficiently block the charge transfer of free nanoparticles in an aqueous solution.

  10. A modular molecular photovoltaic system based on phospholipid/alkanethiol hybrid bilayers: photocurrent generation and modulation.

    PubMed

    Xie, Hong; Jiang, Kai; Zhan, Wei

    2011-10-21

    Monolayer quantities of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), incorporated with either fullerenes or ruthenium tris(bipyridyl) (Ru(bpy)(3)(2+)) complexes, were formed on ferrocene-terminated C11-alkanethiol self-assembled monolayers (SAMs) through lipid fusion. Thus formed hybrid structures are characterized by quartz crystal microbalance, UV-vis spectroscopy, cyclic voltammetry and impedance analysis. In comparison to lipid monolayers deposited on C12-alkanethiol SAMs, photocurrent generation from these ferrocene-based structures is significantly modulated, displaying attenuated anodic photocurrents and enhanced cathodic photocurrents. While a similar trend was observed for the two photoagents studied, the degree of such modulations was always found to be greater in fullerene-incorporated bilayers. These findings are evaluated in the context of the film structure, energetics of the involved photo(electrochemical) species and cross-membrane electron-transfer processes.

  11. Model of self assembled monolayer based molecular diodes made of ferrocenyl-alkanethiols

    NASA Astrophysics Data System (ADS)

    Duche, David; Planchoke, Ujwol; Dang, Florian-Xuan; Le Rouzo, Judikael; Bescond, Marc; Simon, Jean-Jacques; Balaban, Teodor Silviu; Escoubas, Ludovic

    2017-03-01

    There has been significant work investigating the use of self assembled monolayers (SAMs) made of ferrocenyl terminated alkanethiols for realizing molecular diodes, leading to remarkably large forward-to-reverse current rectification ratios. In this study, we use a multiband barrier tunneling model to examine the electrical properties of SAM-based molecular diodes made of HSC9Fc, HSC11Fc, and HSCiFcC13-i (0 ≤ i ≤ 13). Using our simple physical model, we reproduce the experimental data of charge transport across various ferrocenyl substituted alkanethiols performed by Nijhuis, Reus, and Whitesides [J. Am. Chem. Soc. 132, 18386-184016 (2010)] and Yuan et al. [Nat. Commun. 6, 6324 (2015)]. Especially, the model allows predicting the rectification direction in HSCiFcC13-i (0 ≤ i ≤ 13) based molecular diodes depending on the position of the ferrocenyl (Fc) moiety within the molecules. We show that the asymmetry of the barrier length at both sides of the Highest Occupied Molecular Orbital of the ferrocenyl moiety strongly contributes to the rectifying properties of ferrocenyl-alkanethiol based molecular junctions. Furthermore, our results reveal that bound and quasi-bound states play an important role in the charge transport.

  12. Spontaneously adsorbed monolayer films: Fabrication, characterization, and application of monolayers of alkanethiol and sulfur-bearing cyclodestrin derivatives

    SciTech Connect

    Chinkap, Chung.

    1991-03-12

    Monolayers of n-alkanethiols (CH{sub 3}(CH{sub 2}){sub n}SH, n=1--17) and sulfur-bearing cyclodextrin derivatives spontaneously adsorbed on Ag and Au have been studied with a variety of surface characterization methods, such as infrared inflection spectroscopy, contact angle measurements, electro-chemistry, optical ellipsometry, and scanning tunneling microscopy. Long chain n-alkanethiols monolayers on Ag and Au are insulating to electron transfer and have contact angles indicative of well-ordered hydrocarbon terminated structures. Infrared and contact angle data indicate a different orientation of the methyl group with respect to the surface for chains with odd and even numbers of methylene groups. Compared to monolayers on Au, the alkanethiol monolayers on Ag are oriented more towards the surface normal. The observed odd-even effect methyl group orientation for these monolayers on Ag is offset by a methylene group from that on Au. The relationships between the structure and packing of the monolayers on Ag and Au and the composition, roughness, and crystallinity of the substrate are also discussed. Monolayers of sulfur-bearing cyclodextrin derivatives on Au and Ag are fabricated by spontaneous adsorption and characterized by the above techniques. Size-selectively and molecular recognition of the {alpha}- and {beta}- cyclodextrin cavity are shown with our monolayers. Because of molecular recognition, p-nitrophenol is retained preferrentially by the cyclodextrin monolayers over o-nitrophenol. 146 refs., 44 figs., 5 tabs.

  13. Kinetics of alkanethiol monolayer desorption from gold in air.

    PubMed

    Shadnam, Mohammad Reza; Amirfazli, A

    2005-10-14

    Thermal desorption of an alkanethiol monolayer from a gold substrate into a gaseous medium under ambient pressure was investigated using XPS and it was found that there exist 2 consecutive 1st order kinetics mechanisms with activation energies of 29.9 and 32.7 kcal mol(-1), respectively, i.e. on average approximately 15% higher than reports for liquid media desorption.

  14. AMINO ACID COMPOSITION AND C-TERMINAL RESIDUES OF ALGAL BILIPROTEINS,

    DTIC Science & Technology

    R-phycoerythrin from Ceramium rubrum and C- phycocyanin from Nostoc nuscorum were obtained in purified form by fractional crystallization, followed by...as amino acids. Alanine was identified as the only C-terminal amino acid of R-phycoerythrin, each molecule of which contained about 12 terminal groups. Serine was identified as the only C-terminal group of C- phycocyanin . (Author)

  15. Supported phospholipid/alkanethiol biomimetic membranes: insulating properties.

    PubMed Central

    Plant, A L; Gueguetchkeri, M; Yap, W

    1994-01-01

    A novel model lipid bilayer membrane is prepared by the addition of phospholipid vesicles to alkanethiol monolayers on gold. This supported hybrid bilayer membrane is rugged, easily and reproducibly prepared in the absence of organic solvent, and is stable for very long periods of time. We have characterized the insulating characteristics of this membrane by examining the rate of electron transfer and by impedance spectroscopy. Supported hybrid bilayers formed from phospholipids and alkanethiols are pinhole-free and demonstrate measured values of conductivity and resistivity which are within an order of magnitude of that reported for black lipid membranes. Capacitance values suggest a dielectric constant of 2.7 for phospholipid membranes in the absence of organic solvent. The protein toxin, melittin, destroys the insulating capability of the phospholipid layer without significantly altering the bilayer structure. This model membrane will allow the assessment of the effect of lipid membrane perturbants on the insulating properties of natural lipid membranes. PMID:7811924

  16. Self-assembly of alkanethiolates directs sulfur bonding with GaAs(100)

    NASA Astrophysics Data System (ADS)

    Mancheno-Posso, Pablo; Muscat, Anthony J.

    2017-03-01

    Molecules that contain linear alkane chains self-assemble on a variety of surfaces changing the degree of wetting, lubricity, and reactivity. We report on the reoxidation of GaAs(100) in air after adsorbing five alkanethiols (CnH2n+1-SH where n = 3, 6, 12, 18, 20) and one alkanedithiol (HS-(CH2)8-SH) deposited from the liquid phase. The alignment of the alkane chains forms a self-assembled layer, however, air diffuses readily through the carbon layer and reaches the surface. The impact of alignment is to improve the bonding of sulfur with the surface atoms which reduces the oxidation rate based on fitting the data to a reaction-diffusion model. The layer thickness and molecular density scale linearly with the number of carbon atoms in the alkane chain. The thickness of the alkanethiolate (RS-) layer grows by 0.87 ± 0.06 Å for each C atom in the chain and the surface density by 0.13 ± 0.03 molecule per nm2 per C atom up to a coverage of 5.0 molecules/nm2 for n = 20 or 0.8 monolayer. The surface coverage increases with length because interactions between methylene (CH2) groups in neighboring chains reduce the tilt angle of the molecules with the surface normal. The tight packing yields areas per alkanethiolate as low as 20 Å2 for n = 20. The amount of C in the layer divided by the chain length is approximately constant up to n = 12 but increases sharply by a factor of 2-4× for n = 18 and 20 based on the C 1s X-ray photoelectron spectroscopy (XPS) peak. Fourier transform infrared (FTIR) spectroscopy shows that the asymmetric methylene stretch shifts continuously to lower wavenumber and the relative peak area increases sharply with the length of the alkane chain. Fitting the data to a reaction-diffusion model shows that for times less than 30 min the surface oxide coverage does not depend on the thickness of the self-assembled layer nor the diffusivity of oxygen through the layer. Instead increasing the layer thickness makes more S available for bonding with the

  17. The role of alkanethiol spacers in a metal surface-based label-free DNA detection system

    NASA Astrophysics Data System (ADS)

    Peng, Hsin-I.; Nuffer, Zachary M.; Miller, Benjamin L.

    2009-02-01

    We have been developing an array-based DNA biosensor, in which DNA oligonucleotides are readily immobilized onto Au surfaces via terminal thiol groups to serve as probes for the detection of oligonucleotides in solution. One common strategy to minimize steric effects and non-specific oligonucleotide-surface interactions derived from a high surface probe density employs thiol molecules as spacers. In this study, we tested nine different alkanethiol molecules with the goal of identifying a relationship between the chemical structure of each molecule and its performance as a spacer molecule. Among the nine different spacers, 4-mercapto-1-butanol and 1-decanethiol were found to yield the optimal performance as spacers, while spacers with a bulky tert-butyl group or a ring structure (2-methyl-2-propanethiol, cyclohexyl mercaptan and thiophenol) yielded poorer performance. Spacers with a short, branched carbon chain (1- mercapto-2-propanol and 3-mercapto-1,2-propanediol) provided an intermediate performance. These results suggest that DNA sensor response is highly sensitive to the chemical structure of the alkanethiol molecules that are employed as spacer molecules.

  18. Nucleic acid analysis using terminal-phosphate-labeled nucleotides

    DOEpatents

    Korlach, Jonas; Webb, Watt W.; Levene, Michael; Turner, Stephen; Craighead, Harold G.; Foquet, Mathieu

    2008-04-22

    The present invention is directed to a method of sequencing a target nucleic acid molecule having a plurality of bases. In its principle, the temporal order of base additions during the polymerization reaction is measured on a molecule of nucleic acid, i.e. the activity of a nucleic acid polymerizing enzyme on the template nucleic acid molecule to be sequenced is followed in real time. The sequence is deduced by identifying which base is being incorporated into the growing complementary strand of the target nucleic acid by the catalytic activity of the nucleic acid polymerizing enzyme at each step in the sequence of base additions. A polymerase on the target nucleic acid molecule complex is provided in a position suitable to move along the target nucleic acid molecule and extend the oligonucleotide primer at an active site. A plurality of labelled types of nucleotide analogs are provided proximate to the active site, with each distinguishable type of nucleotide analog being complementary to a different nucleotide in the target nucleic acid sequence. The growing nucleic acid strand is extended by using the polymerase to add a nucleotide analog to the nucleic acid strand at the active site, where the nucleotide analog being added is complementary to the nucleotide of the target nucleic acid at the active site. The nucleotide analog added to the oligonucleotide primer as a result of the polymerizing step is identified. The steps of providing labelled nucleotide analogs, polymerizing the growing nucleic acid strand, and identifying the added nucleotide analog are repeated so that the nucleic acid strand is further extended and the sequence of the target nucleic acid is determined.

  19. Communication: Site-dependent reactivity between chlorine atoms and mixed-chain-length alkanethiolate monolayers

    NASA Astrophysics Data System (ADS)

    Lee, David Y.; Kandel, S. Alex

    2013-10-01

    The chemical reaction of atomic chlorine with mixed monolayers of alkanethiolates having different chain lengths was investigated. In situ scanning tunneling microscopy was used to acquire time-lapsed series of images, allowing the measurement of the effect of monolayer structure and composition on reactivity. The rate of chemical reaction is strongly site-dependent. In particular, the boundary between two different-length alkanethiolates greatly promotes the reactivity of nearby molecules, much more so than any other native defect typical of single-component alkanethiolate monolayers.

  20. Engineering cytochrome P450 BM3 of Bacillus megaterium for terminal oxidation of palmitic acid.

    PubMed

    Brühlmann, Fredi; Fourage, Laurent; Ullmann, Christophe; Haefliger, Olivier P; Jeckelmann, Nicolas; Dubois, Cédric; Wahler, Denis

    2014-08-20

    Directed evolution via iterative cycles of random and targeted mutagenesis was applied to the P450 domain of the subterminal fatty acid hydroxylase CYP102A1 of Bacillus megaterium to shift its regioselectivity towards the terminal position of palmitic acid. A powerful and versatile high throughput assay based on LC-MS allowed the simultaneous detection of primary and secondary oxidation products, which was instrumental for identifying variants with a strong preference for the terminal oxidation of palmitic acid. The best variants identified acquired up to 11 amino acid alterations. Substitutions at F87, I263, and A328, relatively close to the bound substrate based on available crystallographic information contributed significantly to the altered regioselectivity. However, non-obvious residues much more distant from the bound substrate showed surprising strong contributions to the increased selectivity for the terminal position of palmitic acid.

  1. Acute effects of N-terminal progastrin fragments on gastric acid secretion in man.

    PubMed

    Goetze, Jens P; Hansen, Carsten P; Rehfeld, Jens F

    2017-03-01

    We previously identified an N-terminal fragment of progastrin in human antrum and plasma, where it circulates in high concentrations. In this study, we examined the effects of N-terminal progastrin fragments on gastric acid secretion by infusion in healthy individuals. Increasing doses of progastrin fragment 1-35 were infused intravenously during constant gastric acid stimulation by gastrin-17. In addition, the effects of progastrin fragment 1-35, fragment 6-35, and fragment 1-19 on gastrin-17 stimulated acid secretion were tested. The gastrin-17 stimulated acid secretion decreased 30% after administration of a high dose of progastrin fragment 1-35 (P < 0.05). In extension, a 1-h infusion of fragment 1-35 also decreased gastric acid output. In contrast, fragment 6-35 did not affect acid secretion, and a single infusion of gastrin-17 alone did not reveal fading of gastric acid output during the time course of the experiments. The results show that N-terminal fragments of progastrin may acutely affect gastrin-stimulated gastric acid secretion in vivo. Structure-function analysis suggests that the N-terminal pentapeptide of progastrin is required for the effect.

  2. Atmospheric corrosion of Cu, Zn, and Cu-Zn alloys protected by self-assembled monolayers of alkanethiols

    NASA Astrophysics Data System (ADS)

    Hosseinpour, Saman; Forslund, Mattias; Johnson, C. Magnus; Pan, Jinshan; Leygraf, Christofer

    2016-06-01

    In this article results from earlier studies have been compiled in order to compare the protection efficiency of self-assembled monolayers (SAM) of alkanethiols for copper, zinc, and copper-zinc alloys exposed to accelerated indoor atmospheric corrosion conditions. The results are based on a combination of surface spectroscopy and microscopy techniques. The protection efficiency of investigated SAMs increases with chain length which is attributed to transport hindrance of the corrosion stimulators in the atmospheric environment, water, oxygen and formic acid, towards the copper surface. The transport hindrance is selective and results in different corrosion products on bare and on protected copper. Initially the molecular structure of SAMs on copper is well ordered, but the ordering is reduced with exposure time. Octadecanethiol (ODT), the longest alkanethiol investigated, protects copper significantly better than zinc, which may be attributed to the higher bond strength of Cu-S than of Zn-S. Despite these differences, the corrosion protection efficiency of ODT for the single phase Cu20Zn brass alloy is equally efficient as for copper, but significantly less for the heterogeneous double phase Cu40Zn brass alloy.

  3. Microwave-Accelerated Surface Modification of Plasmonic Gold Thin Films with Self-Assembled Monolayers of Alkanethiols

    PubMed Central

    Grell, Tsehai A.J.; Alabanza, Anginelle M.; Gaskell, Karen; Aslan, Kadir

    2013-01-01

    A rapid surface modification technique for the formation of self-assembled monolayers (SAMs) of alkanethiols on gold thin films using microwave heating in less than 10 min is reported. In this regard, SAMs of two model alkanethiols, 11-mercaptoundecanoic acid (11-MUDA, to generate a hydrophilic surface) and undecanethiol (UDET, a hydrophobic surface), were successfully formed on gold thin films using selective microwave heating in 1) a semi-continuous and 2) a continuous fashion and at room temperature (24 hours, control experiment, no microwave heating). The formation of SAMs of 11-MUDA and UDET were confirmed by contact angle measurements, Fourier–transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The contact angles for water on SAMs formed by the selective microwave heating and conventional room temperature incubation technique (24 hours) were measured to be similar for 11-MUDA and UDET. FT-IR spectroscopy results confirmed that the internal structure of SAMs prepared using both microwave heating and at room temperature were similar. XPS results revealed that the organic and sulfate contaminants found on bare gold thin films were replaced by SAMs after the surface modification process was carried out using both microwave heating and at room temperature. PMID:24083414

  4. Microwave-accelerated surface modification of plasmonic gold thin films with self-assembled monolayers of alkanethiols.

    PubMed

    Grell, Tsehai A J; Alabanza, Anginelle M; Gaskell, Karen; Aslan, Kadir

    2013-10-29

    A rapid surface modification technique for the formation of self-assembled monolayers (SAMs) of alkanethiols on gold thin films using microwave heating in <10 min is reported. In this regard, SAMs of two model alkanethiols, 11-mercaptoundecanoic acid (11-MUDA, to generate a hydrophilic surface) and undecanethiol (UDET, a hydrophobic surface), were successfully formed on gold thin films using selective microwave heating in (1) a semicontinuous fashion and (2) a continuous fashion at room temperature (24 h, control experiment, no microwave heating). The formation of SAMs of 11-MUDA and UDET was confirmed by contact angle measurements, Fourier transform infrared (FT-IR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The contact angles for water on SAMs formed by the selective microwave heating and conventional room temperature incubation technique (24 h) were measured to be similar for 11-MUDA and UDET. FT-IR spectroscopy results confirmed that the internal structures of SAMs prepared using both microwave heating and room temperature were similar. XPS results revealed that the organic and sulfate contaminants found on bare gold thin films were replaced by SAMs after the surface modification process had been conducted using both microwave heating and room temperature.

  5. Bordetella dermonecrotic toxin binds to target cells via the N-terminal 30 amino acids.

    PubMed

    Fukui-Miyazaki, Aya; Ohnishi, Shinya; Kamitani, Shigeki; Abe, Hiroyuki; Horiguchi, Yasuhiko

    2011-03-01

    Bordetella dermonecrotic toxin (DNT) affects the biological function of host cells by activating intracellular Rho GTPases. The toxin binds to unidentified receptor(s) via 54 N-terminal amino acids, undergoes intramolecular cleavage on the C-terminal side of Arg(44) by furin or furin-like protease, and eventually enters the cytoplasm where the Rho GTPases reside. The binding to the receptor(s) and intramolecular cleavage are essential for DNT to intoxicate cells, and the 54 amino-acid binding domain encompasses the cleavage site, however, it is unclear whether these two events are related. In this study, we could narrow down the cell-binding domain to the N-terminal amino acids 2-30. The region does not contain the furin-recognition site, indicating that the cell binding and the intramolecular cleavage are independent events.

  6. Imaging Pancreatic Cancer with Folic Acid Terminated Luminescent Silicon Nanocrystals

    NASA Astrophysics Data System (ADS)

    Erogbogbo, Folarin; Swihart, Mark T.

    2010-10-01

    Quantum dots have great potential for visualization of medically relevant targets such as cancer. However, potential toxicity, stemming from the use of heavy metal based semidonductor materials, has been a major impediment to use of quantum dots in vivo. Silicon is an inherently non-toxic element. By combining the unique optical properties of silicon quantum dots with fundamentals of cancer biology, we can develop probes that safely target and enable the visualization of cancer cells. Many cancer cells overexpress folate receptors, making the folate receptors a suitable target for cancer imaging evaluations. Here, we report the synthesis of folic acid coated silicon quantum dots for targeting pancreatic cancer cells. Folic acid on the silicon quantum dots improves selectivity and may decrease possible negative side effects. This demonstration adds to the evidence that silicon can be sucessfully used for biological imaging.

  7. Ascorbate as a pro-oxidant: mild N-terminal modification with vinylboronic acids.

    PubMed

    Ohata, Jun; Ball, Zachary T

    2017-02-04

    We describe divergent reactivity of vinylboronic acids for protein modification. In addition to previously reported copper-catalyzed backbone N-H modification, ascorbate in air mediates N-terminal functionalization with the same vinylboronate reagents. This mild and selective aqueous reactivity enables selective single-modification of the B chain of human insulin.

  8. Complete amino acid sequence of the N-terminal extension of calf skin type III procollagen.

    PubMed Central

    Brandt, A; Glanville, R W; Hörlein, D; Bruckner, P; Timpl, R; Fietzek, P P; Kühn, K

    1984-01-01

    The N-terminal extension peptide of type III procollagen, isolated from foetal-calf skin, contains 130 amino acid residues. To determine its amino acid sequence, the peptide was reduced and carboxymethylated or aminoethylated and fragmented with trypsin, Staphylococcus aureus V8 proteinase and bacterial collagenase. Pyroglutamate aminopeptidase was used to deblock the N-terminal collagenase fragment to enable amino acid sequencing. The type III collagen extension peptide is homologous to that of the alpha 1 chain of type I procollagen with respect to a three-domain structure. The N-terminal 79 amino acids, which contain ten of the 12 cysteine residues, form a compact globular domain. The next 39 amino acids are in a collagenase triplet sequence (Gly- Xaa - Yaa )n with a high hydroxyproline content. Finally, another short non-collagenous domain of 12 amino acids ends at the cleavage site for procollagen aminopeptidase, which cleaves a proline-glutamine bond. In contrast with type I procollagen, the type III procollagen extension peptides contain interchain disulphide bridges located at the C-terminus of the triple-helical domain. PMID:6331392

  9. Controlling noncovalent interactions between a lysine-rich α-helical peptide and self-assembled monolayers of alkanethiols on Au through functional group diversity

    NASA Astrophysics Data System (ADS)

    Raigoza, Annette F.; Onyirioha, Kristeen; Webb, Lauren J.

    2017-02-01

    Reliably attaching a structured biomolecule to an inorganic substrate would enable the preparation of surfaces that incorporate both biological and inorganic functions and structures. To this end, we have previously developed a procedure using the copper(I)-catalyzed click reaction to tether synthetic α-helical peptides carrying two alkyne groups to well-ordered alkanethiol self-assembled monolayers (SAM) on a Au(111) surface, in which the SAM is composed of a mixture of methyl and azide termination. Proteins, however, are composed of many diverse functional groups, and this composition directly effects protein structure, interactions, and reactivity. Here, we explore the utility of mixed SAMs with alternative terminating functional groups to tune and direct the reactivity of the surface through noncovalent peptide-surface interactions. We study both polar surfaces (OH-terminated) and charged surfaces (COOH- and NH3-terminated, which are negatively and positively charged, respectively, under our reaction conditions). Surfaces were functionalized with a bipolar peptide composed of Lys and Leu residues that could express different interactions through either hydrophilic and/or charge (Lys) or hydrophobic (Leu) influences. X-ray photoelectron spectroscopy (XPS) and surface infrared spectroscopy were used to characterize surfaces at all stages of the peptide functionalization procedure. This strategy resulted in a high density of surface-bound α-helices without aggregation. Mixed SAMs that included a positively charged alkanethiol along with the azide-terminated thiol resulted in a more efficient reaction and better alignment of the peptide with the azide on the surface. Negatively charged surfaces increased physisorption of the peptide, which was then removed during sample rinsing. This work demonstrates that varying easily controlled chemical inputs during the functionalization steps allows the reaction conditions to be balanced for the chemical needs of a

  10. Novel solid-phase synthesis of thiol-terminated-poly(alpha-amino acid)-drug conjugate.

    PubMed

    Palacios, P; Bussat, P; Bichon, D

    1991-01-01

    A new method using a controlled pore glass solid support for the preparation of a thiol-terminated-polymerdrug, notably poly-L-glutamate-daunomycin having a terminal thiol group, is described. The method consists of first polymerizing an ester-protected glutamic acid onto an amino-disulfide functionalized controlled pore glass support. The ester protecting group is then removed, freeing the gamma-carboxyl groups of the grafted polymer which then allows it to react with daunomycin. Finally, the disulfide bond linking the conjugated polymer-drug to the solid support is broken by thiolysis, thus releasing the desired product. The final product consists of only polymer-drug conjugates with terminal thiol groups (global yield 26%). This novel method is much simpler and more elegant than more conventional preparation methods requiring solution phase techniques.

  11. Dielectric properties and frequency response of self-assembled monolayers of alkanethiols.

    PubMed

    Wang, Bing; Luo, Jianglong; Wang, Xiaoping; Wang, Haiqian; Hou, J G

    2004-06-08

    This paper presents dielectric properties of alkanethiol self-assembled monolayers (SAMs) under an ac electric field. Using a Hg-SAM/SAM-Hg junction, we measured the ac impedance of alkanethiol SAMs using a sinusoidal perturbation of 30 mV (peak-to-peak) with frequency ranging from 1 Hz to 1 MHz at zero bias. Semicircles at higher frequencies and at middle frequencies along with Warburg lines at lower frequencies were observed in complex plane impedance plots, that is, Nyquist plots. The frequency response of SAMs was analyzed by modeling the junction using an equivalent circuit and fitting the Nyquist plots. The semicircles at higher frequencies are attributed to the effect of the SAM/SAM interfaces, and the ones at middle frequencies are attributed to the effect of alkanethiol SAMs. The comparison in the plots of the imaginary part of the impedance Z against frequency for the bare Hg electrodes (in pure ethanal) and the SAM-covered Hg electrodes (in alkanethiol solution) supports the analysis. The Warburg lines are attributed to a certain ionic impurity. The dielectric loss spectra are further analyzed. Chain-length-dependent peaks, which correspond to different relaxation mechanisms, at higher frequencies and middle frequencies were observed in the spectra of the dissipation factor (tan delta vs frequency). The peaks move to small frequency with the increase of chain length of alkanethiols. Using a correlation of peak position with the chain length, we then derived active energies of 39-99 meV for alkanethiol SAMs of C7-C18 under an ac electric field.

  12. Uncoupling of retinoic acid signaling from tailbud development before termination of body axis extension.

    PubMed

    Cunningham, Thomas J; Zhao, Xianling; Duester, Gregg

    2011-10-01

    During the early stages of body axis extension, retinoic acid (RA) synthesized in somites by Raldh2 represses caudal fibroblast growth factor (FGF) signaling to limit the tailbud progenitor zone. Excessive RA down-regulates Fgf8 and triggers premature termination of body axis extension, suggesting that endogenous RA may function in normal termination of body axis extension. Here, we demonstrate that Raldh2-/- mouse embryos undergo normal down-regulation of tailbud Fgf8 expression and termination of body axis extension in the absence of RA. Interestingly, Raldh2 expression in wild-type tail somites and tailbud from E10.5 onwards does not result in RA activity monitored by retinoic acid response element (RARE)-lacZ. Treatment of wild-type tailbuds with physiological levels of RA or retinaldehyde induces RARE-lacZ activity, validating the sensitivity of RARE-lacZ and demonstrating that deficient RA synthesis in wild-type tail somites and tailbud is due to a lack of retinaldehyde synthesis. These studies demonstrate an early uncoupling of RA signaling from mouse tailbud development and show that termination of body axis extension occurs in the absence of RA signaling.

  13. Microscopic mechanism of electron transfer through the hydrogen bonds between carboxylated alkanethiol molecules connected to gold electrodes

    SciTech Connect

    Li, Yang; Tu, Xingchen; Wang, Minglang; Wang, Hao; Hou, Shimin; Sanvito, Stefano

    2014-11-07

    The atomic structure and the electron transfer properties of hydrogen bonds formed between two carboxylated alkanethiol molecules connected to gold electrodes are investigated by employing the non-equilibrium Green's function formalism combined with density functional theory. Three types of molecular junctions are constructed, in which one carboxyl alkanethiol molecule contains two methylene, –CH{sub 2}, groups and the other one is composed of one, two, or three –CH{sub 2} groups. Our calculations show that, similarly to the cases of isolated carboxylic acid dimers, in these molecular junctions the two carboxyl, –COOH, groups form two H-bonds resulting in a cyclic structure. When self-interaction corrections are explicitly considered, the calculated transmission coefficients of these three H-bonded molecular junctions at the Fermi level are in good agreement with the experimental values. The analysis of the projected density of states confirms that the covalent Au–S bonds localized at the molecule-electrode interfaces and the electronic coupling between –COOH and S dominate the low-bias junction conductance. Following the increase of the number of the –CH{sub 2} groups, the coupling between –COOH and S decreases deeply. As a result, the junction conductance decays rapidly as the length of the H-bonded molecules increases. These findings not only provide an explanation to the observed distance dependence of the electron transfer properties of H-bonds, but also help the design of molecular devices constructed through H-bonds.

  14. Inhibition of Escherichia coli Biofilm Formation by Self-Assembled Monolayers of Functional Alkanethiols on Gold▿ †

    PubMed Central

    Hou, Shuyu; Burton, Erik A.; Simon, Karen A.; Blodgett, Dustin; Luk, Yan-Yeung; Ren, Dacheng

    2007-01-01

    Bacterial biofilms cause serious problems, such as antibiotic resistance and medical device-related infections. To further understand bacterium-surface interactions and to develop efficient control strategies, self-assembled monolayers (SAMs) of alkanethiols presenting different functional groups on gold films were analyzed to determine their resistance to biofilm formation. Escherichia coli was labeled with green florescence protein, and its biofilm formation on SAM-modified surfaces was monitored by confocal laser scanning microscopy. The three-dimensional structures of biofilms were analyzed with the COMSTAT software to obtain information about biofilm thickness and surface coverage. SAMs presenting methyl, l-gulonamide (a sugar alcohol tethered with an amide bond), and tri(ethylene glycol) (TEG) groups were tested. Among these, the TEG-terminated SAM was the most resistant to E. coli biofilm formation; e.g., it repressed biofilm formation by E. coli DH5α by 99.5% ± 0.1% for 1 day compared to the biofilm formation on a bare gold surface. When surfaces were patterned with regions consisting of methyl-terminated SAMs surrounded by TEG-terminated SAMs, E. coli formed biofilms only on methyl-terminated patterns. Addition of TEG as a free molecule to growth medium at concentrations of 0.1 and 1.0% also inhibited biofilm formation, while TEG at concentrations up to 1.5% did not have any noticeable effects on cell growth. The results of this study suggest that the reduction in biofilm formation on surfaces modified with TEG-terminated SAMs is a result of multiple factors, including the solvent structure at the interface, the chemorepellent nature of TEG, and the inhibitory effect of TEG on cell motility. PMID:17483274

  15. Selective heterogeneous acid catalyzed esterification of N-terminal sulfyhdryl fatty acids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our interest in thiol fatty acids lies in their antioxidative, free radical scavenging, and metal ion scavenging capabilities as applied to cosmeceutical and skin care formulations. The retail market is filled with products containing the disulfide-containing free fatty acid, lipoic acid. These pr...

  16. New insights into the electrochemical desorption of alkanethiol SAMs on gold

    PubMed Central

    Pensa, Evangelina; Vericat, Carolina; Grumelli, Doris; Salvarezza, Roberto C.; Park, Sung Hyun; Longo, Gabriel S.; Szleifer, Igal

    2012-01-01

    A combination of Polarization Modulation Infrared Reflection Absorption Spectroscopy (PMIRRAS) under electrochemical control, Electrochemical Scanning Tunneling Microscopy (ECSTM) and Molecular Dynamics (MD) simulations has been used to shed light on the reductive desorption process of dodecanethiol (C12) and octadecanethiol (C18) SAMs on gold in aqueous electrolytes. Experimental PMIRRAS, ECSTM and MD simulations data for C12 desorption are consistent with formation of randomly distributed micellar aggregates stabilized by Na+ ions, coexisting with a lying-down phase of molecules. The analysis of pit and Au island coverage before and after desorption is consistent with the thiolate-Au adatoms models. On the other hand, PMIRRAS and MD data for C18 indicate that the desorbed alkanethiolates adopt a Na+ ion-stabilized bilayer of interdigitated alkanethiolates, with no evidence of lying down molecules. MD simulations also show that both the degree of order and tilt angle of the desorbed alkanethiolates change with the surface charge on the metal, going from bilayers to micelles. These results demonstrate the complexity of the alkanethiol desorption in the presence of water and the fact that chain length and counterions play a key role in a complex structure. PMID:22870508

  17. Amino acid residues 201-205 in C-terminal acidic tail region plays a crucial role in antibacterial activity of HMGB1

    PubMed Central

    2009-01-01

    Background Antibacterial activity is a novel function of high-mobility group box 1 (HMGB1). However, the functional site for this new effect is presently unknown. Methods and Results In this study, recombinant human HMGB1 A box and B box (rHMGB1 A box, rHMGB1 B box), recombinant human HMGB1 (rHMGB1) and the truncated C-terminal acidic tail mutant (tHMGB1) were prepared by the prokaryotic expression system. The C-terminal acidic tail (C peptide) was synthesized, which was composed of 30 amino acid residues. Antibacterial assays showed that both the full length rHMGB1 and the synthetic C peptide alone could efficiently inhibit bacteria proliferation, but rHMGB1 A box and B box, and tHMGB1 lacking the C-terminal acidic tail had no antibacterial function. These results suggest that C-terminal acidic tail is the key region for the antibacterial activity of HMGB1. Furthermore, we prepared eleven different deleted mutants lacking several amino acid residues in C-terminal acidic tail of HMGB1. Antibacterial assays of these mutants demonstrate that the amino acid residues 201-205 in C-terminal acidic tail region is the core functional site for the antibacterial activity of the molecule. Conclusion In sum, these results define the key region and the crucial site in HMGB1 for its antibacterial function, which is helpful to illustrating the antibacterial mechanisms of HMGB1. PMID:19751520

  18. Gold-Adatom-Mediated Bonding in Self-Assembled Short-Chain Alkanethiolate Species on the Au(111) Surface

    SciTech Connect

    Maksymovych, P.; Sorescu, D.C.; Yates, J.T., Jr.

    2006-10-06

    Microscopic evidence for Au-adatom-induced self-assembly of alkanethiolate species on the Au(111) surface is presented. Based on STM measurements and density-functional theory calculations, a new model for the low-coverage self-assembled monolayer of alkanethiolate on the Au(111) surface is developed, which involves the adsorbate complexes incorporating Au adatoms. It is also concluded that the Au(111) herringbone reconstruction is lifted by the alkanethiolate self-assembly because the reconstructed surface layer provides reactive Au adatoms that drive self-assembly.

  19. Germanium oxide removal by citric acid and thiol passivation from citric acid-terminated Ge(100).

    PubMed

    Collins, Gillian; Aureau, Damien; Holmes, Justin D; Etcheberry, Arnaud; O'Dwyer, Colm

    2014-12-02

    Many applications of germanium (Ge) are underpinned by effective oxide removal and surface passivation. This important surface treatment step often requires H-X (X = Cl, Br, I) or HF etchants. Here, we show that aqueous citric acid solutions are effective in the removal of GeOx. The stability of citric acid-treated Ge(100) is compared to HF and HCl treated surfaces and analyzed by X-ray photoelectron spectroscopy. Further Ge surface passivation was investigated by thiolation using alkane monothiols and dithiols. The organic passivation layers show good stability with no oxide regrowth observed after 3 days of ambient exposure.

  20. Adhesion of human leukocytes to biomaterials: an in vitro study using alkanethiolate monolayers with different chemically functionalized surfaces.

    PubMed

    Barbosa, Judite N; Barbosa, Mário A; Aguas, Artur P

    2003-06-15

    The adhesion of human leukocytes to self-assembled monolayers of well-defined surface chemistry was investigated in vitro. Polymorphonuclear (PMN) and mononuclear leukocytes were isolated from human blood by centrifugation techniques. The effect on adhesion of cell activation produced by pre-incubation of leukocytes with phytohemagglutinin (PHA) and phorbol 12-myristate 13-acetate (PMA) was also studied. Gold substrates were modified by treatment with alkanethiols with three different terminal chemical groups: COOH, OH, and CH(3). After incubation with the two subpopulations of leukocytes, the monolayers were washed, treated with fixative, stained with a Giemsa method, and observed by light microscopy to quantify the number of attached leukocytes. Comparative quantification of the density of leukocyte adhesion to the three types of self-assembled monolayers was determined. The hydrophobic surface expressing CH(3) was found to be the one that induced the highest adhesion density of leukocytes, both of PMN and mononuclear cells. In vitro activation of both mononuclear and PMN leukocytes further increased cell adhesion to the chemically defined monolayers that were used. This enhancement was higher for PHA-activated than for PMA-stimulated mononuclear cells, whereas PMA treatment of neutrophils resulted in a higher rate of adhesion of these cells than PHA stimulation.

  1. Terminal acidic shock inhibits sour beer bottle conditioning by Saccharomyces cerevisiae.

    PubMed

    Rogers, Cody M; Veatch, Devon; Covey, Adam; Staton, Caleb; Bochman, Matthew L

    2016-08-01

    During beer fermentation, the brewer's yeast Saccharomyces cerevisiae experiences a variety of shifting growth conditions, culminating in a low-oxygen, low-nutrient, high-ethanol, acidic environment. In beers that are bottle conditioned (i.e., carbonated in the bottle by supplying yeast with a small amount of sugar to metabolize into CO2), the S. cerevisiae cells must overcome these stressors to perform the ultimate act in beer production. However, medium shock caused by any of these variables can slow, stall, or even kill the yeast, resulting in production delays and economic losses. Here, we describe a medium shock caused by high lactic acid levels in an American sour beer, which we refer to as "terminal acidic shock". Yeast exposed to this shock failed to bottle condition the beer, though they remained viable. The effects of low pH/high [lactic acid] conditions on the growth of six different brewing strains of S. cerevisiae were characterized, and we developed a method to adapt the yeast to growth in acidic beer, enabling proper bottle conditioning. Our findings will aid in the production of sour-style beers, a trending category in the American craft beer scene.

  2. Self-Assembled Monolayers of n-Alkanethiols Suppress Hydrogen Evolution and Increase the Efficiency of Rechargeable Iron Battery Electrodes

    SciTech Connect

    Malkhandi, S; Yang, B; Manohar, AK; Prakash, GKS; Narayanan, SR

    2013-01-09

    Iron-based rechargeable batteries, because of their low cost, eco-friendliness, and durability, are extremely attractive for large-scale energy storage. A principal challenge in the deployment of these batteries is their relatively low electrical efficiency. The low efficiency is due to parasitic hydrogen evolution that occurs on the iron electrode during charging and idle stand. In this study, we demonstrate for the first time that linear alkanethiols are very effective in suppressing hydrogen evolution on alkaline iron battery electrodes. The alkanethiols form self-assembled monolayers on the iron electrodes. The degree of suppression of hydrogen evolution by the alkanethiols was found to be greater than 90%, and the effectiveness of the alkanethiol increased with the chain length. Through steady-state potentiostatic polarization studies and impedance measurements on high-purity iron disk electrodes, we show that the self-assembly of alkanethiols suppressed the parasitic reaction by reducing the interfacial area available for the electrochemical reaction. We have modeled the effect of chain length of the alkanethiol on the surface coverage, charge-transfer resistance, and double-layer capacitance of the interface using a simple model that also yields a value for the interchain interaction energy. We have verified the improvement in charging efficiency resulting from the use of the alkanethiols in practical rechargeable iron battery electrodes. The results of battery tests indicate that alkanethiols yield among the highest faradaic efficiencies reported for the rechargeable iron electrodes, enabling the prospect of a large-scale energy storage solution based on low-cost iron-based rechargeable batteries.

  3. Kinetics of electron transfer through ferrocene-terminated alkanethiol monolayers on gold

    SciTech Connect

    Smalley, J.F.; Feldberg, S.W.; Newton, M.D.; Liu, Y.P.; Chidsey, C.E.D.; Linford, M.R.

    1995-08-31

    The kinetics of electron transfer between a substrate gold electrode and a self-assembled monolayer formed from CH{sub 3}(CH{sub 2}){sub n-1}SH and ({eta}{sup 5} C{sub 5}H{sub 5})Fe ({eta}{sup 5}-C{sub 5}H{sub 4})CO{sub 2}(CH{sub 2}){sub n}SH were studied as a function of n, the number of methylenes in the alkyl chain tethering the ferrocene moiety to the electrode, using the indirect laser-induced temperature jump method (ILIT). For 5 {<=} n {<=} 9 the standard electron-transfer rate constants vary according to {kappa}{sub {tau}a,n=0} exp[-{beta}{sub n}n] where {kappa}{sub {tau}a,n=0} is the (extrapolated) rate constant for the electron transfer at n = 0. At {Tau} = 25{degree}C, {kappa}{sub {tau}a,n} 0 {approx_equal} 6 x 10{sup 8} s{sup -1} and {beta}{sub n} = 1.21 x 0.05. The ILIT method allows rates to be measured that are too fast to be measured by conventional chronoamperometry at a macroelectrode, which is limited to rate constants of {<=} 10{sup 4} s{sup -1}. Using a Marcus formalism, the reorganization energy, {lambda}, for the electron-transfer process at a given n was determined from the slope of an Arrhenius plot over the temperature range 15-55{degree}C. Values of {lambda} determined from Arrhenius slopes for n = 8 and 9 using ILIT are in reasonable agreement with the value of {lambda} previously deduced from the potential dependence of the rate constant for n = 16. 39 refs., 13 figs., 3 tabs.

  4. Infrared spectroelectrochemical characterization of ferrocene-terminated alkanethiolate monolayers at gold

    SciTech Connect

    Popenoe, D.D.; Deinhammer, R.S.; Porter, M.D. Iowa State Univ., Ames, IA )

    1992-10-01

    Cyclic voltammetry and in situ infrared reflection-absorption spectroscopy with electrochemical modulation were applied to the study of monolayers self-assembled from 11-mercaptoundecyl ferrocene-carboxylate (FcCOOC[sub 11]SH) at gold. Voltammetry was used to assess both the reactivity and stability of the surface film in various aqueous electrolytes. The results of these studies indicated that the ferrocenyl monolayers are relatively unstable at pH > 2, except when perchlorate is the dominant anion present. A large change in double-layer capacitance observed upon oxidation of the ferrocenyl end group was attributed to the creation of cationic sites in the diffuse layer. Compositional and structural correlations between the monolayer and the redox chemistry of the ferrocenyl end group were probed using the in situ spectroscopic technique. The features observed in the differential spectra of the oxidized form of the film were ascribed to changes in the bond strengths of the adsorbate as a result of generation of a ferricinium ion. No detectable changes in orientation of the polymethylene chains as a function of applied voltage were observed. The spectral data also suggest that the redox chemistry leads to a reorientation of the water molecules in the region near the ferrocenyl end group. Vibrational mode assignments for FcCOOC[sub 11]SH, based on studies of several analogs with different alkoxy groups, are presented along with infrared spectra and band assignments for several isotopically labeled ferrocenyl esters (i.e., ethyl ferrocenecarboxylate, ethyl-d[sub 5] ferrocenecarboxylate, and 2-(dimethylamino)ethyl ferrocenecarboxylate). 55 refs., 7 figs., 2 tabs.

  5. Change of cobalt magnetic anisotropy and spin polarization with alkanethiolates self-assembled monolayers

    NASA Astrophysics Data System (ADS)

    Campiglio, Paolo; Breitwieser, Romain; Repain, Vincent; Guitteny, Solène; Chacon, Cyril; Bellec, Amandine; Lagoute, Jérôme; Girard, Yann; Rousset, Sylvie; Sassella, Adele; Imam, Mighfar; Narasimhan, Shobhana

    2015-06-01

    We demonstrate that the deposition of a self-assembled monolayer of alkanethiolates on a 1 nm thick cobalt ultrathin film grown on Au(111) induces a spin reorientation transition from in-plane to out-of-plane magnetization. Using ab initio calculations, we show that a methanethiolate layer changes slightly both the magnetocrystalline and shape anisotropy, both effects almost cancelling each other out for a 1 nm Co film. Finally, the change in hysteresis cycles upon alkanethiolate adsorption could be assigned to a molecular-induced roughening of the Co layer, as shown by STM. In addition, we calculate how a methanethiolate layer modifies the spin density of states of the Co layer and we show that the spin polarization at the Fermi level through the organic layer is reversed as compared to the uncovered Co. These results give new theoretical and experimental insights for the use of thiol-based self-assembled monolayers in spintronic devices.

  6. Nucleation and island growth of alkanethiolate ligand domains on gold nanoparticles.

    PubMed

    Wang, Yifeng; Zeiri, Offer; Neyman, Alevtina; Stellacci, Francesco; Weinstock, Ira A

    2012-01-24

    The metal oxide cluster α-AlW(11)O(39)(9-) (1), readily imaged by cryogenic transmission electron microscopy (cryo-TEM), is used as a diagnostic protecting anion to investigate the self-assembly of alkanethiolate monolayers on electrostatically stabilized gold nanoparticles in water. Monolayers of 1 on 13.8 ± 0.9 nm diameter gold nanoparticles are displaced from the gold surface by mercaptoundecacarboxylate, HS(CH(2))(10)CO(2)(-) (11-MU). During this process, no aggregation is observed by UV-vis spectroscopy, and the intermediate ligand-shell organizations of 1 in cryo-TEM images indicate the presence of growing hydrophobic domains, or "islands", of alkanethiolates. UV-vis spectroscopic "titrations", based on changes in the surface plasmon resonance upon exchange of 1 by thiol, reveal that the 330 ± 30 molecules of 1 initially present on each gold nanoparticle are eventually replaced by 2800 ± 30 molecules of 11-MU. UV-vis kinetic data for 11-MU-monolayer formation reveal a slow phase, followed by rapid self-assembly. The Johnson, Mehl, Avrami, and Kolmogorov model gives an Avrami parameter of 2.9, indicating continuous nucleation and two-dimensional island growth. During nucleation, incoming 11-MU ligands irreversibly displace 1 from the Au-NP surface via an associative mechanism, with k(nucleation) = (6.1 ± 0.4) × 10(2) M(-1) s(-1), and 19 ± 8 nuclei, each comprised of ca. 8 alkanethiolates, appear on the gold-nanoparticle surface before rapid growth becomes kinetically dominant. Island growth is also first-order in [11-MU], and its larger rate constant, k(growth), (2.3 ± 0.2) × 10(4) M(-1) s(-1), is consistent with destabilization of molecules of 1 at the boundaries between the hydrophobic (alkanethiolate) and the electrostatically stabilized (inorganic) domains.

  7. Cyclic Voltammetric Analysis of Ferrocene Alkanethiol Monolayer Electrode Kinetics Based on Marcus Theory

    DTIC Science & Technology

    1994-07-01

    Analysis of Ferrocene Alkanethiol Monolayer Electrode Kinectics Based on Marcus Theory & AUTHOR(S) N00014-90-J-1230 L. Tender, M. T. Carter, and R. W. Murray...immobilized monolayers in cyclic voltammetry is developed based on the Marcus free energy -rate relation. Numerical calculations show that when the...applied over-potential exceeds ca. 30% of the reorganizational energy of the electrode reaction, voltammetry predicted from Marcus theory differs from

  8. From Alkanes to Carboxylic Acids: Terminal Oxygenation by a Fungal Peroxygenase.

    PubMed

    Olmedo, Andrés; Aranda, Carmen; Del Río, José C; Kiebist, Jan; Scheibner, Katrin; Martínez, Angel T; Gutiérrez, Ana

    2016-09-26

    A new heme-thiolate peroxidase catalyzes the hydroxylation of n-alkanes at the terminal position-a challenging reaction in organic chemistry-with H2 O2 as the only cosubstrate. Besides the primary product, 1-dodecanol, the conversion of dodecane yielded dodecanoic, 12-hydroxydodecanoic, and 1,12-dodecanedioic acids, as identified by GC-MS. Dodecanal could be detected only in trace amounts, and 1,12-dodecanediol was not observed, thus suggesting that dodecanoic acid is the branch point between mono- and diterminal hydroxylation. Simultaneously, oxygenation was observed at other hydrocarbon chain positions (preferentially C2 and C11). Similar results were observed in reactions of tetradecane. The pattern of products formed, together with data on the incorporation of (18) O from the cosubstrate H2 (18) O2 , demonstrate that the enzyme acts as a peroxygenase that is able to catalyze a cascade of mono- and diterminal oxidation reactions of long-chain n-alkanes to give carboxylic acids.

  9. Charge transport through dicarboxylic-acid-terminated alkanes bound to graphene-gold nanogap electrodes

    NASA Astrophysics Data System (ADS)

    Liu, Longlong; Zhang, Qian; Tao, Shuhui; Zhao, Cezhou; Almutib, Eman; Al-Galiby, Qusiy; Bailey, Steven W. D.; Grace, Iain; Lambert, Colin J.; Du, Jun; Yang, Li

    2016-07-01

    Graphene-based electrodes are attractive for single-molecule electronics due to their high stability and conductivity and reduced screening compared with metals. In this paper, we use the STM-based matrix isolation I(s) method to measure the performance of graphene in single-molecule junctions with one graphene electrode and one gold electrode. By measuring the length dependence of the electrical conductance of dicarboxylic-acid-terminated alkanes, we find that the transport is consistent with phase-coherent tunneling, but with an attenuation factor of βN = 0.69 per methyl unit, which is lower than the value measured for Au-molecule-Au junctions. Comparison with density-functional-theory calculations of electron transport through graphene-molecule-Au junctions and Au-molecule-Au junctions reveals that this difference is due to the difference in Fermi energies of the two types of junction, relative to the frontier orbitals of the molecules. For most molecules, their electrical conductance in graphene-molecule-Au junctions is higher than that in Au-molecule-Au junctions, which suggests that graphene offers superior electrode performance, when utilizing carboxylic acid anchor groups.Graphene-based electrodes are attractive for single-molecule electronics due to their high stability and conductivity and reduced screening compared with metals. In this paper, we use the STM-based matrix isolation I(s) method to measure the performance of graphene in single-molecule junctions with one graphene electrode and one gold electrode. By measuring the length dependence of the electrical conductance of dicarboxylic-acid-terminated alkanes, we find that the transport is consistent with phase-coherent tunneling, but with an attenuation factor of βN = 0.69 per methyl unit, which is lower than the value measured for Au-molecule-Au junctions. Comparison with density-functional-theory calculations of electron transport through graphene-molecule-Au junctions and Au

  10. Size does matter: 18 amino acids at the N-terminal tip of an amino acid transporter in Leishmania determine substrate specificity

    PubMed Central

    Schlisselberg, Doreen; Mazarib, Eldar; Inbar, Ehud; Rentsch, Doris; Myler, Peter J.; Zilberstein, Dan

    2015-01-01

    Long N-terminal tails of amino acid transporters are known to act as sensors of the internal pool of amino acids and as positive regulators of substrate flux rate. In this study we establish that N-termini of amino acid transporters can also determine substrate specificity. We show that due to alternative trans splicing, the human pathogen Leishmania naturally expresses two variants of the proline/alanine transporter, one 18 amino acid shorter than the other. We demonstrate that the longer variant (LdAAP24) translocates both proline and alanine, whereas the shorter variant (∆18LdAAP24) translocates just proline. Remarkably, co-expressing the hydrophilic N-terminal peptide of the long variant with ∆18LdAAP24 was found to recover alanine transport. This restoration of alanine transport could be mediated by a truncated N-terminal tail, though truncations exceeding half of the tail length were no longer functional. Taken together, the data indicate that the first 18 amino acids of the negatively charged N-terminal LdAAP24 tail are required for alanine transport and may facilitate the electrostatic interactions of the entire negatively charged N-terminal tail with the positively charged internal loops in the transmembrane domain, as this mechanism has been shown to underlie regulation of substrate flux rate for other transporters. PMID:26549185

  11. Determination of self-exchange rate of alkanethiolates in self-assembled monolayers on gold using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

    PubMed

    Kang, Hyunook; Kim, Yongbin; Choi, Inseong; Chang, Rakwoo; Yeo, Woon-Seok

    2014-09-16

    In this paper, we describe a new method for determining the exchange rates of alkanethiolates in self-assembled monolayers (SAMs) on gold using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to analyze the compositions of the alkanethiolate in SAMs rapidly and directly. In particular, to investigate the self-exchange of alkanethiols, we prepared a deuterated alkanethiol that has the same molecular properties as the non-deuterated alkanethiol but a different molecular weight. SAMs consisting of deuterated alkanethiolates were immersed in a solution of the non-deuterated alkanethiol, and the influences of the immersion time, temperature, concentration, and solvent on the self-exchange rates were investigated. Furthermore, we assessed the exchange rates among alkanethiols with different carbon chain lengths and different size of ethylene glycol units. In addition, we performed molecular dynamics simulations using a model SAM system in order to understand the molecular mechanism of the exchange process.

  12. [omega]-Hydroxylation of Oleic Acid in Vicia sativa Microsomes (Inhibition by Substrate Analogs and Inactivation by Terminal Acetylenes).

    PubMed Central

    Pinot, F.; Bosch, H.; Alayrac, C.; Mioskowski, C.; Vendais, A.; Durst, F.; Salaun, J. P.

    1993-01-01

    Oleic acid (18:1) is hydroxylated exclusively on the terminal methyl by a microsomal cytochrome P-450-dependent system ([omega]-OAH) from clofibrate-induced Vicia sativa L. (var minor) seedlings (F. Pinot, J.-P. Salaun, H. Bosch, A. Lesot, C. Mioskowski, F. Durst [1992] Biochem Biophys Res Commun 184: 183-193). This reaction was inactivated by two terminal acetylenes: (Z)-9-octadecen-17-ynoic acid (17-ODCYA) and the corresponding epoxide, (Z)-9,10-epoxyoctadecan-17-ynoic acid (17-EODCYA). Inactivation was mechanism-based, with an apparent binding constant of 21 and 32 [mu]M and half-lives of 16 and 19 min for 17-ODCYA and 17-EODCYA, respectively. We have investigated the participation of one or more [omega]-hydroxylase isoforms in the oxidation of fatty acids in this plant system. Lauric acid (12:0) is [omega]-hydroxylated by the cytochrome P-450 [omega]-hydroxylase [omega]-LAH (J.-P. Salaun, A. Simon, F. Durst [1986] Lipids 21: 776-779). Half-lives of [omega]-OAH and [omega]-LAH in the presence of 40 [mu]M 17-ODCYA were 23 and 41 min, respectively. Inhibition of oleic acid [omega]-hydroxylation was competitive with linoleic acid (18:2), but noncompetitive with lauric acid (12:0). In contrast, oleic acid did not inhibit [omega]-hydroxylation of lauric acid. Furthermore, 1-pentadecyltriazole inhibited [omega]-hydroxylation of oleic acid but not of lauric acid. These results suggest that distinct monooxygenases catalyze [omega]-hydroxylation of medium- and long-chain fatty acids in V. sativa microsomes. PMID:12231907

  13. Anodic passivation of tin by alkanethiol self-assembled monolayers examined by cyclic voltammetry and coulometry.

    PubMed

    Worley, Barrett C; Ricks, William A; Prendergast, Michael P; Gregory, Brian W; Collins, Ross; Cassimus, John J; Thompson, Raymond G

    2013-10-22

    The self-assembly of medium chain length alkanethiol monolayers on polycrystalline Sn electrodes has been investigated by cyclic voltammetry and coulometry. These studies have been performed in order to ascertain the conditions under which their oxidative deposition can be achieved directly on the oxide-free Sn surface, and the extent to which these electrochemically prepared self-assembled monolayers (SAMs) act as barriers to surface oxide growth. This work has shown that the potentials for their oxidative deposition are more cathodic (by 100-200 mV) than those for Sn surface oxidation and that the passivating abilities of these SAMs improve with increasing film thickness (or chain length). Oxidative desorption potentials for these films have been observed to shift more positively, and in a highly linear fashion, with increasing film thickness (~75 mV/CH2). Although reductive desorption potentials for the SAMs are in close proximity to those for reduction of the surface oxide (SnOx), little or no SnOx formation occurs unless the potential is made sufficiently anodic that the monolayers start to be removed oxidatively. Our coulometric data indicate that the charge involved with alkanethiol reductive desorption or oxidative deposition is consistent with the formation of a close-packed monolayer, given uncertainties attributable to surface roughness and heterogeneity phenomena. These experiments also reveal that the quantity of charge passed during oxidative desorption is significantly larger than what would be predicted for simple alkylsulfinate or alkylsulfonate formation, suggesting that oxidative removal involves a more complex oxidation mechanism. Analogous chronocoulometric experiments for short-chain alkanethiols on polycrystalline Au electrodes have evidenced similar oxidative charge densities. This implies that the mechanism for oxidative desorption on both surfaces may be very similar, despite the significant differences in the inherent dissolution

  14. Sequence dependent N-terminal rearrangement and degradation of peptide nucleic acid (PNA) in aqueous solution

    NASA Technical Reports Server (NTRS)

    Eriksson, M.; Christensen, L.; Schmidt, J.; Haaima, G.; Orgel, L.; Nielsen, P. E.

    1998-01-01

    The stability of the PNA (peptide nucleic acid) thymine monomer inverted question markN-[2-(thymin-1-ylacetyl)]-N-(2-aminoaminoethyl)glycine inverted question mark and those of various PNA oligomers (5-8-mers) have been measured at room temperature (20 degrees C) as a function of pH. The thymine monomer undergoes N-acyl transfer rearrangement with a half-life of 34 days at pH 11 as analyzed by 1H NMR; and two reactions, the N-acyl transfer and a sequential degradation, are found by HPLC analysis to occur at measurable rates for the oligomers at pH 9 or above. Dependent on the amino-terminal sequence, half-lives of 350 h to 163 days were found at pH 9. At pH 12 the half-lives ranged from 1.5 h to 21 days. The results are discussed in terms of PNA as a gene therapeutic drug as well as a possible prebiotic genetic material.

  15. Effect of gamma radiation on alkanethiolate-capped gold nanoparticles: Theoretical studies

    NASA Astrophysics Data System (ADS)

    Fernández-García, M. E.; Pérez-Alvarez, M.; Mendoza-Anaya, D.; Gutiérrez-Wing, C.

    2016-03-01

    Theoretical studies of the effect of gamma irradiation on alkanethiolate-capped gold nanoparticles are presented. Icosahedral, decahedral and fcc nanoparticles protected with 1-dodecanethiolate (SC12) were obtained by molecular mechanics simulations, analyzing the effect of gamma irradiation through MonteCarlo. The studied doses were 1, 10 and 20 kGy. It was observed that slight structural modifications of the metallic core might occur and these are dependent on the shape of the nanoparticle. However, the most significant effect was observed on the organic passivating layer, where torsions, bending and scission of the alkyl chains were detected.

  16. Unusual mechanism for the short-range electron transfer within gold-alkanethiol-ionic-liquid films of subnanometer thickness

    SciTech Connect

    Khoshtariya, Dimitri E.; Dolidze, Tina D.; Eldik, Rudi van

    2009-12-15

    Exploiting nanoscopically tunable composite gold-alkanethiol-ionic-liquid/ferrocene self-assembled systems with tunable electron transfer distance, we discovered in the case of thinner alkanethiol films a thermally activated electron transfer pattern totally controlled by the viscosity-related slow relaxation mode(s) of the ionic liquid acting as the reactant's fluctuating environment. This pattern manifested through the activation enthalpy and volume parameters that are identical to those for viscous flow was explained in terms of the extreme adiabatic mechanism with a vanishing Marcus barrier (via the exponential Franck-Condon-like term approaching unity).

  17. Unusual mechanism for the short-range electron transfer within gold-alkanethiol-ionic-liquid films of subnanometer thickness

    NASA Astrophysics Data System (ADS)

    Khoshtariya, Dimitri E.; Dolidze, Tina D.; van Eldik, Rudi

    2009-12-01

    Exploiting nanoscopically tunable composite gold-alkanethiol-ionic-liquid/ferrocene self-assembled systems with tunable electron transfer distance, we discovered in the case of thinner alkanethiol films a thermally activated electron transfer pattern totally controlled by the viscosity-related slow relaxation mode(s) of the ionic liquid acting as the reactant’s fluctuating environment. This pattern manifested through the activation enthalpy and volume parameters that are identical to those for viscous flow was explained in terms of the extreme adiabatic mechanism with a vanishing Marcus barrier (via the exponential Franck-Condon-like term approaching unity).

  18. Synthesis of 1,3-Amino Alcohols, 1,3-Diols, Amines, and Carboxylic Acids from Terminal Alkynes.

    PubMed

    Zeng, Mingshuo; Herzon, Seth B

    2015-09-04

    The half-sandwich ruthenium complexes 1-3 activate terminal alkynes toward anti-Markovnikov hydration and reductive hydration under mild conditions. These reactions are believed to proceed via addition of water to metal vinylidene intermediates (4). The functionalization of propargylic alcohols by metal vinylidene pathways is challenging owing to decomposition of the starting material and catalytic intermediates. Here we show that catalyst 2 can be employed to convert propargylic alcohols to 1,3-diols in high yield and with retention of stereochemistry at the propargylic position. The method is also amenable to propargylic amine derivatives, thereby establishing a route to enantioenriched 1,3-amino alcohol products. We also report the development of formal anti-Markovnikov reductive amination and oxidative hydration reactions to access linear amines and carboxylic acids, respectively, from terminal alkynes. This chemistry expands the scope of products that can be prepared from terminal alkynes by practical and high-yielding metal-catalyzed methods.

  19. Effect of phytic acid and microbial phytase on the flow and amino acid composition of endogenous protein at the terminal ileum of growing broiler chickens.

    PubMed

    Cowieson, A J; Ravindran, V

    2007-10-01

    The effects of phytic acid and microbial phytase on the flow and composition of endogenous protein at the terminal ileum of broiler chickens were investigated using the peptide alimentation method. Phytic acid (fed as the sodium salt) was included in a synthetic diet at 8.5, 11.5 and 14.5 g/kg (or 2.4, 3.2 and 4.0 g/kg phytate-phosphorus) and each diet was fed without or with an Escherichia coli-derived microbial phytase at 500 phytase units/kg diet. A control containing no phytate was fed as a comparison to estimate basal endogenous flows. Ingestion of phytic acid increased (P < 0.05) the flow of endogenous amino acids and N by an average of 47 % at the lowest phytic acid concentration and 87 % at the highest. The addition of microbial phytase reduced (P < 0.05) the inimical effects of phytic acid on endogenous amino acid flow at all dietary phytic acid levels. The composition of endogenous protein was also influenced (P < 0.10-0.001) by increasing phytic acid concentrations and phytase addition. The effects of phytic acid and phytase on endogenous flow and composition of endogenous protein, however, varied depending on the amino acid. It is concluded that the effects of phytase on amino acid digestibility may be mediated, in part, through a route of reduced endogenous loss.

  20. Shape-controlled synthesis of NIR absorbing branched gold nanoparticles and morphology stabilization with alkanethiols.

    PubMed

    Van de Broek, B; Frederix, F; Bonroy, K; Jans, H; Jans, K; Borghs, G; Maes, G

    2011-01-07

    Gold nanoparticles are ideal candidates for clinical applications if their plasmon absorption band is situated in the near infrared region (NIR) of the electromagnetic spectrum. Various parameters, including the nanoparticle shape, strongly influence the position of this absorption band. The aim of this study is to produce stabilized NIR absorbing branched gold nanoparticles with potential for biomedical applications. Hereto, the synthesis procedure for branched gold nanoparticles is optimized varying the different synthesis parameters. By subsequent electroless gold plating the plasmon absorption band is shifted to 747.2 nm. The intrinsic unstable nature of the nanoparticles' morphology can be clearly observed by a spectral shift and limits their use in real applications. However, in this article we show how the stabilization of the branched structure can be successfully achieved by exchanging the initial capping agent for different alkanethiols and disulfides. Furthermore, when using alkanethiols/disulfides with poly(ethylene oxide) units incorporated, an increased stability of the gold nanoparticles is achieved in high salt concentrations up to 1 M and in a cell culture medium. These achievements open a plethora of opportunities for these stabilized branched gold nanoparticles in nanomedicine.

  1. Modification of hydroxylated alumina and silica surfaces using sequential reactions with dimethylzinc and n-alkanethiols

    NASA Astrophysics Data System (ADS)

    Boiadjiev, Vassil Iordanov

    2000-10-01

    This work demonstrates that it is possible to grow thin organic films chemically bound to hydroxylated alumina and silica surfaces by sequential adsorption of trimethylaluminum (TMA) and alcohols, and dimethylzinc and n-alkanethiols, at room temperature. The presence of the resulting alkoxide and thiolate species is demonstrated using infrared spectroscopy and, in the case of thiolates on silica, by nuclear magnetic resonance spectroscopy. The similarity between the reaction on high-surface area alumina and silica, and on planar surfaces allows the surface species to be identified in vacuo prior to attempting self-assembly on planar surfaces. Almost identical results obtained from chemical vapor deposition in vacuo and from sequential reaction in benzene solutions allow chemical grafting of low-vapor pressure, long-chain n-alkanethiols to the dimethylzinc-modified hydroxylated surfaces from solution. This is first studied on high-surface area silica substrates and then expanded to self-assembly on planar hydroxylated silicon substrate. The major reaction pathway for formation and thermal decomposition of aluminum alkoxide and Zn-bound ethanethiolate surface species on alumina and silica substrates is proposed based on the experimental results. It is suggested that initial adsorption of methanol on TMA-modified alumina covered by Al(CH3)2(ads), rapidly replaces a methyl by methoxy species at room temperature. Further reaction of methanol at ˜400 K replaces the second methyl species leading to Al(OCH3)2(ads) . This thermally decomposes on heating to yield primarily dimethyl ether and surface formate species. It is also very reactive with water and rapidly forms adsorbed alumina and methanol. Dimethylzinc reacts with hydroxylated alumina and silica at room temperature to form adsorbed monomethylzinc surface species and evolve methane. Temperature dependent studies reveal that these species are stable at room temperature and gradually decompose in vacuo. Adsorbed

  2. Basic amino acid residues located in the N-terminal region of BEND3 are essential for its nuclear localization

    SciTech Connect

    Shiheido, Hirokazu Shimizu, Jun

    2015-02-20

    BEN domain-containing protein 3 (BEND3) has recently been reported to function as a heterochromatin-associated protein in transcriptional repression in the nucleus. BEND3 should have nuclear localization signals (NLSs) to localize to the nucleus in light of its molecular weight, which is higher than that allowed to pass through nuclear pore complexes. We here analyzed the subcellular localization of deletion/site-directed mutants of human BEND3 by an immunofluorescence assay in an attempt to identify the amino acids essential for its nuclear localization. We found that three basic amino acid residues located in the N-terminal region of BEND3 (BEND3{sub 56–58}, KRK) are essential, suggesting that these residues play a role as a functional NLS. These results provide valuable information for progressing research on BEND3. - Highlights: • BEND3 localizes to the nucleus. • The N-terminal 60 amino acids region of BEND3 contains NLS. • Amino acids located between 56 and 58 of BEND3 (KRK) are part of NLS. • KRK motif is highly conserved among BEND3 homologs.

  3. Removal of self-assembled monolayers of alkanethiolates on gold by plasma cleaning

    NASA Astrophysics Data System (ADS)

    Raiber, Kevin; Terfort, Andreas; Benndorf, Carsten; Krings, Norman; Strehblow, Hans-Henning

    2005-12-01

    Plasmas of hydrogen or oxygen were used to remove self-assembled monolayers (SAMs) of alkanethiolates from gold surfaces. X-ray photoelectron spectroscopy (XPS), scanning tunneling microscopy (STM), ellipsometry, and contact angle measurements were used to compare the efficiency of the different plasmas and to explore their respective influence on the surface topology. Both plasmas were able to remove the SAM from the gold surface within less than 60 s. While the hydrogen plasma produces a de facto sulfur-free surface, oxygen plasma cleaning leads to an Au 2O 3 surface contaminated with oxidized sulfur species (probably sulfonates and sulfate). Nevertheless, the plasmas alter the roughness of the gold surfaces only marginally, as demonstrated by STM.

  4. Method for measuring the self-assembly of alkanethiols on gold at femtomolar concentrations.

    PubMed

    Rijal, Kishan; Mutharasan, Raj

    2007-06-05

    We describe a cantilever-based method for measuring the self-assembly of alkanethiols on a gold surface in a flow system that permits easy step changes in concentration and acquire a continuous in situ measure of the resulting chemisorption through the change in resonance frequency. A gold-coated (2.2 mm2), piezoelectric-excited, millimeter-sized cantilever (PEMC) sensor was exposed to 1-hexadecanethiol (HDT) in ethanol at concentrations ranging from 1 fM to 1 mM, sequentially and separately. A high-order flexural mode at approximately 850 kHz was monitored during the self-assembly. The resonance frequency decreases as a result of increased mass as chemisorption occurs on the surface. We show for the first time that the chemisorption of HDT at 1 fM is readily measurable and gave a response of 220 +/- 13 Hz (n = 4). At higher concentrations (10 and 100 fM; 1, 10, and 100 pM; 1, 10, and 100 nM; 1 microM; and 1 mM), the responses were proportionately, but nonlinearly, higher. At high concentrations (1 mM), the responses to C4, C8, C11, C16, and C18 alkanethiols were linearly proportional and were complete in approximately 25 min. We report for the first time that, once the Au surface is equilibrated at 1 pM, further chemisorption at a lower HDT concentration does not take place, even though over 99% of surface adsorption sites are available. At 1 fM, the overall chemisorption rate did not increase with a 2-fold increase in the HDT flow rate, suggesting that chemisorption at 1 fM is not transport-limited. The measured overall chemisorption rate constant at 1 fM was more rapid than 0.1 min-1.

  5. MIES investigation of alkanethiol monolayers self-assembled on Au(111) and Ag(111) surfaces

    NASA Astrophysics Data System (ADS)

    Heinz, Bertram; Morgner, Harald

    1997-02-01

    Self-assembled monolayers of alkanethiols (SH(CH 2) mCH 3, m=7,8,9,11,15,17) have been prepared to study their electronic properties by means of metastable induced electron spectroscopy (MIES). The thermal metastable helium atoms used as projectiles in this technique interact exclusively with molecular orbitals exposed at the top of the film, which makes the method perfectly surface sensitive. Access of metastable helium atoms to the methyl group or to the CH 2-groups of the alkyl chain depends strongly on the orientation of the molecular axis. The MIE-spectrum of nonanethiol on Au(111) and the MIE-spectrum of hexadecane physisorbed on graphite served as references for upright aligned and flat lying alkyl chains. Both MIE-spectra can be related to the electronic bandstructure of polyethylene. Electron emission originating from the upright methyl groups and flat lying CH 2-groups is distinguished by characteristic intensities in the MIE-spectra. On this basis, a quantity R has been introduced as a measure for the molecular orientation of the alkyl chain at the top surface of the films. The evolution of R with respect to different molecular assemblies of the alkyl chains is consistent with XPS, LEED and UPS results. Within the series of dense and ordered alkanethiol films on gold and silver R decreases monotonously upon increasing the alkyl chain length. This behaviour indicates either the emergence of CH 2-groups at the cost of methyl groups at the top surface or a decreasing degree of orientational order of the methyl groups or both in the case of longer alkyl chains.

  6. Teichuronic acid reducing terminal N-acetylglucosamine residue linked by phosphodiester to peptidoglycan of Micrococcus luteus

    SciTech Connect

    Gassner, G.T.; Dickie, J.P.; Hamerski, D.A.; Magnuson, J.K.; Anderson, J.S. )

    1990-05-01

    Teichuronic acid-peptidoglycan complex isolated from Micrococcus luteus cells by lysozyme digestion in osmotically stabilized medium was treated with mild acid to cleave the linkage joining teichuronic acid to peptidoglycan. This labile linkage was shown to be the phosphodiester which joins N-acetylglucosamine, the residue located at the reducing end of the teichuronic acid, through its anomeric hydroxyl group to a 6-phosphomuramic acid, a residue of the glycan strand of peptidoglycan. {sup 31}P nuclear magnetic resonance spectroscopy of the lysozyme digest of cell walls demonstrated the presence of a phosphodiester which was converted to a phosphomonoester by the conditions which released teichuronic acid from cell walls. Reduction of acid-liberated reducing end groups by NaB{sup 3}H{sub 4} followed by complete acid hydrolysis yielded ({sup 3}H) glucosaminitol from the true reducing end residue of teichuronic acid and ({sup 3}H)glucitol from the sites of fragmentation of teichuronic acid. The amount of N-acetylglucosamine detected was approximately stoichiometric with the amount of phosphate in the complex. Partial fragmentation of teichuronic acid provides an explanation of the previous erroneous identification of the reducing end residue.

  7. Requirement of N-terminal amino acid residues of gp41 for human immunodeficiency virus type 1-mediated cell fusion.

    PubMed Central

    Schaal, H; Klein, M; Gehrmann, P; Adams, O; Scheid, A

    1995-01-01

    An expression vector was designed to test the structural requirements of the gp41 N terminus for human immunodeficiency virus type 1-induced membrane fusion. Mutations in the region coding for the N terminus of gp41 were found to disrupt glycoprotein expression because of deleterious effects on the Rev-responsive element (RRE). Insertion of an additional RRE in the 3'-noncoding sequence of env made possible efficient glycoprotein expression, irrespective of the mutations introduced into the RRE in the natural location. This permitted the insertion of the unique restriction site SpeI within the N-terminal sequences of gp41, allowing convenient and efficient mutation of the gp41 N terminus by using double-stranded synthetic oligonucleotides. Mutants with deletions of 1 to 7 amino acids of the N terminus were constructed. Expression and cleavage of all mutants were confirmed by Western immunoblot analysis with anti-gp41 antibodies. The capability of mutants to induce membrane fusion was monitored following transfection of HeLa-T4+ cell lines with wild-type and mutant expression vectors by electroporation and microinjection. The efficiency of cell-fusing activity decreased drastically with deletion of 3 and 4 amino acids and was completely lost with deletion of 5 amino acids. Cotransfection of the parent and mutant expression vectors resulted in reduced cell-fusing activity. The extent of this dominant interference by mutant glycoprotein paralleled the decrease in cell-fusing activity of the mutants alone. This suggests the existence of a specific N-terminal structure required for fusing activity. However, there does not appear to be a stringent requirement for the precise length of the N terminus. This finding is supported by the length variation of this region among natural human immunodeficiency virus type 1 isolates and is in contrast to the apparent stringency in the length of analogous N-terminal structures of influenza A virus and paramyxovirus fusion

  8. Peptide Mass Fingerprinting and N-Terminal Amino Acid Sequencing of Glycosylated Cysteine Protease of Euphorbia nivulia Buch.-Ham.

    PubMed Central

    Badgujar, Shamkant B.; Mahajan, Raghunath T.

    2013-01-01

    A new cysteine protease named Nivulian-II has been purified from the latex of Euphorbia nivulia Buch.-Ham. The apparent molecular mass of Nivulian-II is 43670.846 Da (MALDI TOF/MS). Peptide mass fingerprint analysis revealed peptide matches to Maturase K (Q52ZV1_9MAGN) of Banksia quercifolia. The N-terminal sequence (DFPPNTCCCICC) showed partial homology with those of other cysteine proteinases of biological origin. This is the first paper to characterize a Nivulian-II of E. nivulia latex with respect to amino acid sequencing. PMID:23476742

  9. Mechanical and charge transport properties of alkanethiol self-assembled monolayers on Au (111) surface: The Role of Molecular Tilt

    SciTech Connect

    Mulleregan, Alice; Qi, Yabing; Ratera, Imma; Park, Jeong Y.; Ashby, Paul D.; Quek, Su Ying; Neaton, J. B.; Salmeron, Miquel

    2007-11-12

    The relationship between charge transport and mechanical properties of alkanethiol self-assembled monolayers (SAM) on Au(111) films has been investigated using an atomic force microscope with a conductive tip. Molecular tilts induced by the pressure applied by the tip cause stepwise increases in film conductivity. A decay constant {beta} = 0.57 {+-} 0.03 {angstrom}{sup -1} was found for the current passing through the film as a function of tip-substrate separation due to this molecular tilt. This is significantly smaller than the value of {approx} 1 {angstrom}{sup -1} found when the separation is changed by changing the length of the alkanethiol molecules. Calculations indicate that for isolated dithiol molecules S-bonded to hollow sites, the junction conductance does not vary significantly as a function of molecular tilt. The impact of S-Au bonding on SAM conductance is discussed.

  10. Basic amino acid residues located in the N-terminal region of BEND3 are essential for its nuclear localization.

    PubMed

    Shiheido, Hirokazu; Shimizu, Jun

    2015-02-20

    BEN domain-containing protein 3 (BEND3) has recently been reported to function as a heterochromatin-associated protein in transcriptional repression in the nucleus. BEND3 should have nuclear localization signals (NLSs) to localize to the nucleus in light of its molecular weight, which is higher than that allowed to pass through nuclear pore complexes. We here analyzed the subcellular localization of deletion/site-directed mutants of human BEND3 by an immunofluorescence assay in an attempt to identify the amino acids essential for its nuclear localization. We found that three basic amino acid residues located in the N-terminal region of BEND3 (BEND356-58, KRK) are essential, suggesting that these residues play a role as a functional NLS. These results provide valuable information for progressing research on BEND3.

  11. Short-term clearance of cell-free nucleic acids after first-trimester termination of pregnancy.

    PubMed

    Jeong, Young-Ju; Borgatta, Lynn; Kapp, Nathalie; Peter, Inga; Bianchi, Diana W; Johnson, Kirby L

    2007-09-01

    To determine the kinetics of the short-term clearance of cell-free nucleic acids in maternal plasma, we conducted a prospective cohort study of 36 women who underwent first-trimester elective surgical termination. By using real-time polymerase chain reaction (PCR) amplification and measurement of the sex-determining region of the Y chromosome (SRY) gene (as a marker of fetal DNA), beta-hCG (a placental messenger RNA transcript), and glyceraldehyde phosphate dehydrogenase (GAPDH; as a marker of both total DNA and mitochondrial RNA), we found that cell-free nucleic acids in maternal plasma are not cleared within 90 minutes after the procedure, in contrast to the case of term delivery, in which levels decrease rapidly after birth.

  12. Mixed self-assembled monolayers of alkanethiolates on ultrasmooth gold do not exhibit contact-angle hysteresis.

    PubMed

    Gupta, Pooja; Ulman, Abraham; Fanfan, Stephanie; Korniakov, Alexander; Loos, Katja

    2005-01-12

    We present the first study of mixed alkanethiolate SAMs on ultrasmooth gold surfaces. By eliminating surface roughness, it became possible, for the first time, to investigate wetting properties as a function of surface chemical composition. In three different surface compositions, it was found that contact-angle hysteresis apparently vanished. This suggests that surface chemical heterogeneity does not contribute to contact-angle hysteresis in mixed SAMs on ultrasmooth gold surfaces.

  13. The N-terminal portion of domain E of retinoic acid receptors alpha and beta is essential for the recognition of retinoic acid and various analogs.

    PubMed

    Ostrowski, J; Hammer, L; Roalsvig, T; Pokornowski, K; Reczek, P R

    1995-03-14

    Utilizing a strategy involving domain exchange between retinoic acid receptors alpha and beta (RAR alpha and RAR beta) and monitoring the transcriptional activity of the resulting chimeric receptors with receptor-selective retinoids, we identified a 70-aa region within the N-terminal portion of the RAR alpha and -beta domain E which is important for an RAR alpha- or RAR beta-specific response. Two amino acid residues within this region, serine-232 (S232) and threonine-239 (T239) in RAR alpha and the corresponding alanine-225 (A225) and isoleucine-232 (I232) in RAR beta, were found to be essential for this effect. In addition, binding studies using the chimeric receptors expressed in Escherichia coli showed that the N-terminal portion of domain E was also important for the characteristic binding profile of t-RA and various retinoids with RAR alpha or RAR beta. Structural predictions of the primary amino acid sequence in this region indicate the presence of an amphipathic helix-turn-helix structure with five hydrophobic amino acids that resemble a leucine zipper motif. The amino acid residues identified by domain swapping, S232 and T239 in RAR alpha and A225 and I232 in RAR beta, were found within the hydrophobic face of an alpha-helix in close proximity to this zipper motif, suggesting that the ligand may interact with the receptor in the region adjacent to a surface involved in protein-protein interactions. This finding may link ligand binding to other processes important for transcriptional activation.

  14. The N-terminal portion of domain E of retinoic acid receptors alpha and beta is essential for the recognition of retinoic acid and various analogs.

    PubMed Central

    Ostrowski, J; Hammer, L; Roalsvig, T; Pokornowski, K; Reczek, P R

    1995-01-01

    Utilizing a strategy involving domain exchange between retinoic acid receptors alpha and beta (RAR alpha and RAR beta) and monitoring the transcriptional activity of the resulting chimeric receptors with receptor-selective retinoids, we identified a 70-aa region within the N-terminal portion of the RAR alpha and -beta domain E which is important for an RAR alpha- or RAR beta-specific response. Two amino acid residues within this region, serine-232 (S232) and threonine-239 (T239) in RAR alpha and the corresponding alanine-225 (A225) and isoleucine-232 (I232) in RAR beta, were found to be essential for this effect. In addition, binding studies using the chimeric receptors expressed in Escherichia coli showed that the N-terminal portion of domain E was also important for the characteristic binding profile of t-RA and various retinoids with RAR alpha or RAR beta. Structural predictions of the primary amino acid sequence in this region indicate the presence of an amphipathic helix-turn-helix structure with five hydrophobic amino acids that resemble a leucine zipper motif. The amino acid residues identified by domain swapping, S232 and T239 in RAR alpha and A225 and I232 in RAR beta, were found within the hydrophobic face of an alpha-helix in close proximity to this zipper motif, suggesting that the ligand may interact with the receptor in the region adjacent to a surface involved in protein-protein interactions. This finding may link ligand binding to other processes important for transcriptional activation. PMID:7892182

  15. [Proteolysis of semax analogues with different N-terminal amino acids by aminopeptidases].

    PubMed

    Shevchenko, K V; V'iunova, T V; Nagaev, I Iu; Andreeva, L A; Alfeeva, L Iu; Miasoedov, N F

    2011-01-01

    Proteolysis of semax (Met-Glu-His-Phe-Pro-Gly-Pro, Sem) and its analogues ([Ala1]Sem, [Gly1]Sem, [Thr1]Sem, [Trp1]Sem) that are differ from semax in substitution of N-terminal Met residue were studied. It is shown that such replacement changes the rate of peptides degradation by N-aminopeptidases (EC 3.4.11.2, Sigma, Type VI, 9.2 units. Akt. / mg). [Ala1]Sem, [Gly1]Sem and [Thr1]Sem semax analogues proved to be more stable to proteolysis than semax (Sem), and their initial product of proteolysis is His-Phe-Pro-Gly-Pro (Sem-5). For triptophan analogue both Glu-His-Phe-Pro-Gly-Pro (Sem-6) and Sem-5 product are formed in similar quantities. It is found that all investigated analogues can be used as inhibitors in Sem proteolysis.

  16. Differential roles of internal and terminal double bonds in docosahexaenoic acid: Comparative study of cytotoxicity of polyunsaturated fatty acids to HT-29 human colorectal tumor cell line.

    PubMed

    Sato, Satoshi B; Sato, Sho; Kawamoto, Jun; Kurihara, Tatsuo

    2011-01-01

    The role of the double bonds in docosahexaenoic acid (22:6(Δ4,7,10,13,16,19); DHA) in cytotoxic lipid peroxidation was studied in a superoxide dismutase-defective human colorectal tumor cell line, HT-29. In a conventional culture, DHA and other polyunsaturated fatty acids (PUFAs) were found to induce acute lipid peroxidation and subsequent cell death. PUFAs that lack one or both the terminal double bonds (Δ19 and Δ4) but share Δ7,10,13,16 such as 22:5(Δ7,10,13,16,19), 22:5(Δ4,7,10,13,16), and 22:4(Δ7,10,13,16) were more effective than DHA. Lipid peroxidation and cell death were completely inhibited, except by 22:4(Δ7,10,13,16) when radical-mediated reactions were suppressed by culturing cells in 2% O(2) in the presence of vitamin E. DHA and C22:5 PUFAs but not 22:4(Δ7,10,13,16) were efficiently incorporated in phosphatidylinositol, regardless of the culturing conditions. These and other results suggested that the internal unsaturations Δ7,10,13,16 were sensitive to lipid peroxidation, whereas the terminal ones Δ19 and Δ4 appeared to be involved in assimilation into phospholipids.

  17. Application of protein N-terminal amidase in enzymatic synthesis of dipeptides containing acidic amino acids specifically at the N-terminus.

    PubMed

    Arai, Toshinobu; Noguchi, Atsushi; Takano, Eriko; Kino, Kuniki

    2013-04-01

    Dipeptides exhibit unique physiological functions and physical properties, e.g., l-aspartyl-l-phenylalanine-methyl ester (Asp-Phe-OMe, aspartame) as an artificial sweetener, and functional studies of peptides have been carried out in various fields. Therefore, to establish a manufacturing process for the useful dipeptides, we investigated its enzymatic synthesis by utilizing an l-amino acid ligase (Lal), which catalyzes dipeptide synthesis in an ATP-dependent manner. Many Lals were obtained, but the Lals recognizing acidic amino acids as N-terminal substrates have not been identified. To increase the variety of dipeptides that are enzymatically synthesized, we proposed a two-step synthesis: Asn-Xaa and Gln-Xaa (Asn, l-asparagine; Gln, l-glutamine; and Xaa, arbitrary amino acids) synthesized by Lals were continuously deamidated by a novel amidase, yielding Asp-Xaa and Glu-Xaa (Asp, l-aspartic acid; and Glu, l-glutamic acid). We searched for amidases that specifically deamidate the N-terminus of Asn or Gln in dipeptides since none have been previously reported. We focused on the protein N-terminal amidase from Saccharomyces cerevisiae (NTA1), and assayed its activity toward dipeptides. Our findings showed that NTA1 deamidated l-asparaginyl-l-valine (Asn-Val) and l-glutaminyl-glycine (Gln-Gly), but did not deamidate l-valyl-l-asparagine and l-alanyl-l-glutamine, suggesting that this deamidation activity is N-terminus specific. The specific activity toward Asn-Val and Gln-Gly were 190 ± 30 nmol min(-1) mg(-1)·protein and 136 ± 6 nmol min(-1) mg(-1)·protein. Additionally, we examined some characteristics of NTA1. Acidic dipeptide synthesis was examined by a combination of Lals and NTA1, resulting in the synthesis of 12 kinds of Asp-Xaa, including Asp-Phe, a precursor of aspartame, and 11 kinds of Glu-Xaa.

  18. 2-Mercaptobenzothiazole doped chitosan/11-alkanethiolate acid composite coating: Dual function for copper protection

    NASA Astrophysics Data System (ADS)

    Bao, Qi; Zhang, Dun; Wan, Yi

    2011-10-01

    Chitosan (CS) hydrogel loaded with the well-known corrosion inhibitor 2-mercaptobenzothiazole (MBT) has been introduced into a composite coating to improve copper protection. This composite coating, which has both anticorrosion and antibacterial properties, was fabricated onto the surface of copper by combining a simple self-assembled monolayer technique with a sol-gel method. The anti-corrosion ability of the coating in 3.5 wt.% NaCl solution was investigated by electrochemical methods including potentiodynamic polarization and electrochemical impedance spectroscopy. The protection efficiency of the coating is 97.70%, calculated on the basis of the corrosion current density. The stability and integrity of the composite coating were evaluated by field emission scanning electron microscopy (FESEM) and energy dispersive spectrometry (EDS). The FESEM and EDS results suggest that the composite coating endows the copper substrate with antibacterial properties, as untreated bare copper underwent microbiologically influenced corrosion in the presence of sulphate reducing bacteria (SRB). This antibacterial feature was further confirmed by the SRB culture method. In a 3.5% NaCl solution and highly corrosive SRB culture media, the as-prepared CS based composite coating gave corrosion protection by exhibiting better barrier effects against the attack of aggressive environments.

  19. Intein-Promoted Cyclization of Aspartic Acid Flanking the Intein Leads to Atypical N-Terminal Cleavage.

    PubMed

    Minteer, Christopher J; Siegart, Nicolle M; Colelli, Kathryn M; Liu, Xinyue; Linhardt, Robert J; Wang, Chunyu; Gomez, Alvin V; Reitter, Julie N; Mills, Kenneth V

    2017-02-28

    Protein splicing is a post-translational reaction facilitated by an intein, or intervening protein, which involves the removal of the intein and the ligation of the flanking polypeptides, or exteins. A DNA polymerase II intein from Pyrococcus abyssi (Pab PolII intein) can promote protein splicing in vitro on incubation at high temperature. Mutation of active site residues Cys1, Gln185, and Cys+1 to Ala results in an inactive intein precursor, which cannot promote the steps of splicing, including cleavage of the peptide bond linking the N-extein and intein (N-terminal cleavage). Surprisingly, coupling the inactivating mutations to a change of the residue at the C-terminus of the N-extein (N-1 residue) from the native Asn to Asp reactivates N-terminal cleavage at pH 5. Similar "aspartic acid effects" have been observed in other proteins and peptides but usually only occur at lower pH values. In this case, however, the unusual N-terminal cleavage is abolished by mutations to catalytic active site residues and unfolding of the intein, indicating that this cleavage effect is mediated by the intein active site and the intein fold. We show via mass spectrometry that the reaction proceeds through cyclization of Asp resulting in anhydride formation coupled to peptide bond cleavage. Our results add to the richness of the understanding of the mechanism of protein splicing and provide insight into the stability of proteins at moderately low pH. The results also explain, and may help practitioners avoid, a side reaction that may complicate intein applications in biotechnology.

  20. Five glutamic acid residues in the C-terminal domain of the ChlD subunit play a major role in conferring Mg(2+) cooperativity upon magnesium chelatase.

    PubMed

    Brindley, Amanda A; Adams, Nathan B P; Hunter, C Neil; Reid, James D

    2015-11-10

    Magnesium chelatase catalyzes the first committed step in chlorophyll biosynthesis by inserting a Mg(2+) ion into protoporphyrin IX in an ATP-dependent manner. The cyanobacterial (Synechocystis) and higher-plant chelatases exhibit a complex cooperative response to free magnesium, while the chelatases from Thermosynechococcus elongatus and photosynthetic bacteria do not. To investigate the basis for this cooperativity, we constructed a series of chimeric ChlD proteins using N-terminal, central, and C-terminal domains from Synechocystis and Thermosynechococcus. We show that five glutamic acid residues in the C-terminal domain play a major role in this process.

  1. Acidic Residues Control the Dimerization of the N-terminal Domain of Black Widow Spiders’ Major Ampullate Spidroin 1

    NASA Astrophysics Data System (ADS)

    Bauer, Joschka; Schaal, Daniel; Eisoldt, Lukas; Schweimer, Kristian; Schwarzinger, Stephan; Scheibel, Thomas

    2016-09-01

    Dragline silk is the most prominent amongst spider silks and comprises two types of major ampullate spidroins (MaSp) differing in their proline content. In the natural spinning process, the conversion of soluble MaSp into a tough fiber is, amongst other factors, triggered by dimerization and conformational switching of their helical amino-terminal domains (NRN). Both processes are induced by protonation of acidic residues upon acidification along the spinning duct. Here, the structure and monomer-dimer-equilibrium of the domain NRN1 of Latrodectus hesperus MaSp1 and variants thereof have been investigated, and the key residues for both could be identified. Changes in ionic composition and strength within the spinning duct enable electrostatic interactions between the acidic and basic pole of two monomers which prearrange into an antiparallel dimer. Upon naturally occurring acidification this dimer is stabilized by protonation of residue E114. A conformational change is independently triggered by protonation of clustered acidic residues (D39, E76, E81). Such step-by-step mechanism allows a controlled spidroin assembly in a pH- and salt sensitive manner, preventing premature aggregation of spider silk proteins in the gland and at the same time ensuring fast and efficient dimer formation and stabilization on demand in the spinning duct.

  2. Novel Odd-Chain Fatty Acids with a Terminal Double Bond in Ovaries of the Limpet Cellana toreuma.

    PubMed

    Kawashima, Hideki; Ohnishi, Masao

    2017-04-01

    Our previous study characterized highly diverse dienoic fatty acids (FA), in particular an uncommon non-methylene-interrupted (NMI) FA, in the ovaries of the Japanese limpet Cellana toreuma belonging to the archaeogastropods, but many minor chemically unidentified FA remain. In this study, among previously unidentified FA (less than 0.1% of total FA), four novel NMI FA with a terminal double bond [7,18-nonadecadienoic (19:2Δ7,18), 11,18-nonadecadienoic (19:2Δ11,18), 7,20-heneicosadienoic (21:2Δ7,20), and 11,20-heneicosadienoic (21:2Δ11,20) acids] were found, along with known 14-pentadecenoic (15:1Δ14), 16-heptadecenoic (17:1Δ16), and 9,18-nonadecadienoic (19:2Δ9,18) acids, based on capillary GC-MS of their methyl esters, 3-pyridylcarbinol derivatives, and argentation thin-layer chromatography. From our findings, possible biosynthetic pathways for the novel FA are discussed.

  3. Acidic Residues Control the Dimerization of the N-terminal Domain of Black Widow Spiders’ Major Ampullate Spidroin 1

    PubMed Central

    Bauer, Joschka; Schaal, Daniel; Eisoldt, Lukas; Schweimer, Kristian; Schwarzinger, Stephan; Scheibel, Thomas

    2016-01-01

    Dragline silk is the most prominent amongst spider silks and comprises two types of major ampullate spidroins (MaSp) differing in their proline content. In the natural spinning process, the conversion of soluble MaSp into a tough fiber is, amongst other factors, triggered by dimerization and conformational switching of their helical amino-terminal domains (NRN). Both processes are induced by protonation of acidic residues upon acidification along the spinning duct. Here, the structure and monomer-dimer-equilibrium of the domain NRN1 of Latrodectus hesperus MaSp1 and variants thereof have been investigated, and the key residues for both could be identified. Changes in ionic composition and strength within the spinning duct enable electrostatic interactions between the acidic and basic pole of two monomers which prearrange into an antiparallel dimer. Upon naturally occurring acidification this dimer is stabilized by protonation of residue E114. A conformational change is independently triggered by protonation of clustered acidic residues (D39, E76, E81). Such step-by-step mechanism allows a controlled spidroin assembly in a pH- and salt sensitive manner, preventing premature aggregation of spider silk proteins in the gland and at the same time ensuring fast and efficient dimer formation and stabilization on demand in the spinning duct. PMID:27681031

  4. Mechanical Properties of Two-Dimensional Alkanethiol-Coated Gold Nanoparticle Membranes

    NASA Astrophysics Data System (ADS)

    Salerno, K. Michael; Bolintineanu, Dan S.; Lane, J. Matthew D.; Grest, Gary S.

    2014-03-01

    Membranes formed from nanoparticle monolayers have been shown to have mechanical properties that may make them suitable for use in micro-scale devices. Metallic-core nanoparticles with short, organic ligands can form membranes with dimensions up to several micrometers, with large elastic moduli. Experimental tests of membranes with different cores and ligands indicate that ligand length as well as core-ligand and ligand-ligand interactions can influence membrane mechanical response. We use explicit-atom molecular dynamics simulations to examine the properties of membranes formed from a two-dimensional hexagonal array of alkanethiol-coated Au nanoparticles. Results are presented for nanoparticle core diameters from 4-6nm, ligand lengths of 10-18 units and carboxyl and methyl end groups, all of which influence the mechanical properties of the membranes. Knowledge of how microstructure and composition influence membrane properties could lead to efficient membrane manufacture with improved mechanical properties. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  5. Understanding the Phase Diagram of Self-Assembled Monolayers of Alkanethiolates on Gold

    PubMed Central

    2016-01-01

    Alkanethiolate monolayers on gold are important both for applications in nanoscience as well as fundamental studies of adsorption and self-assembly at metal surfaces. While considerable experimental effort has been put into understanding the phase diagram of these systems, theoretical work based on density functional theory (DFT) has long been hampered by the inability of conventional exchange-correlation functionals to describe dispersive interactions. In this work, we combine dispersion-corrected DFT calculations using the new vdW-DF-CX functional with the ab initio thermodynamics method to study the stability of dense standing-up and low-coverage lying-down phases on Au(111). We demonstrate that the lying-down phase has a thermodynamic region of stability starting from thiolates with alkyl chains consisting of n ≈ 3 methylene units. This phase emerges as a consequence of a competition between dispersive chain–chain and chain–substrate interactions, where the strength of the latter varies more strongly with n. A phase diagram is derived under ultrahigh-vacuum conditions, detailing the phase transition temperatures of the system as a function of the chain length. The present work illustrates that accurate ab initio modeling of dispersive interactions is both feasible and essential for describing self-assembled monolayers. PMID:27313813

  6. Switching of the Fe Oxida-tion State in Ferro-cene-Capped Alkanethiols

    NASA Astrophysics Data System (ADS)

    Zheng, Fan; Luk, Yan-Yeung; Abbott, Nicholas L.; Himpsel, F. J.

    2005-03-01

    Molecular electronics has been a rapidly-growing area, due to the simplicity of building molecular devices by self-assembly and the promise of extremely low power consumption as a result of pushing the size down to a few molecules per device. A self-assembled monolayer (SAM) of ferrocene-capped alkanethiols is produced in two stable oxidation states of Fe (Fe^2+ and Fe^3+). The oxidation states of Fe are probed with sub-monolayer sensitivity by Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy at the iron L2, 3 edges ^[1]. NEXAFS provides a direct method to distinguish between the oxidation states of submonolayer by comparing with the bulk sample spectrum. The native Fe^2+ layer is converted chemically to Fe^3+, and the Fe^3+ layer can be switched back to Fe^2+ or possibly Fe^0 by irradiation with soft x-rays. The results have implications on switching mechanisms in molecular electronics. [1] Fan Zheng, V. P'erez-Dieste, J. L. McChesney, Yan-Yeung Luk, Nicholas L. Abbott, and F. J. Himpsel, Appl. Phys. Lett, to be submitted.

  7. Highly sensitive detection of influenza virus by boron-doped diamond electrode terminated with sialic acid-mimic peptide

    PubMed Central

    Matsubara, Teruhiko; Ujie, Michiko; Yamamoto, Takashi; Akahori, Miku; Einaga, Yasuaki; Sato, Toshinori

    2016-01-01

    The progression of influenza varies according to age and the presence of an underlying disease; appropriate treatment is therefore required to prevent severe disease. Anti-influenza therapy, such as with neuraminidase inhibitors, is effective, but diagnosis at an early phase of infection before viral propagation is critical. Here, we show that several dozen plaque-forming units (pfu) of influenza virus (IFV) can be detected using a boron-doped diamond (BDD) electrode terminated with a sialic acid-mimic peptide. The peptide was used instead of the sialyloligosaccharide receptor, which is the common receptor of influenza A and B viruses required during the early phase of infection, to capture IFV particles. The peptide, which was previously identified by phage-display technology, was immobilized by click chemistry on the BDD electrode, which has excellent electrochemical characteristics such as low background current and weak adsorption of biomolecules. Electrochemical impedance spectroscopy revealed that H1N1 and H3N2 IFVs were detectable in the range of 20–500 pfu by using the peptide-terminated BDD electrode. Our results demonstrate that the BDD device integrated with the receptor-mimic peptide has high sensitivity for detection of a low number of virus particles in the early phase of infection. PMID:27457924

  8. Electrocatalytic oxidation of dihydronicotineamide adenine dinucleotide on gold electrode modified with catechol-terminated alkanethiol self-assembly.

    PubMed

    Nakano, Koji; Ohkubo, Kimihiko; Taira, Hiroaki; Takagi, Makoto; Imato, Toshihiko

    2008-06-30

    Synthesis of a mercaptoundecaneamide derivative having a terminus of catechol is described. FT-IR spectroscopic characterization showed that the new molecular entry simply undergoes molecular self-assembly on Au substrate surfaces promoting intra- and intermolecular hydrogen bonds to form well-packed monolayers. Cyclic voltammetric (CV) measurements on the monolayer-modified Au electrode revealed that the surface adlayer possesses specific electrochemical activity due to the reversible catechol/o-quinone redox reaction having characteristics of a surface process and also pH-dependence in its formal potential (59 mV per pH). Detailed analysis of CVs gave fundamental electrochemical parameters including the electroactive surface coverage (0.20-0.24 nmol cm(-2)), the transfer coefficients (0.24 in oxidation and 0.81 in reduction), and also the electron transfer rate constant (1.10-2.76 s(-1)). These data were almost consistent to those seen in literature. We have also found that the catechol monolayer modified electrode exhibits an electrocatalytic function in NADH oxidation. That is, the faradaic current appeared reinforcingly at around the same potential where catechol function is oxidized in the monolayer and increased with an increase in the NADH concentration from 1 to 5 mM, and then reached to a plateau indicating a catalyzed reaction pathway. Detailed analyses revealed that the present system could be characterized by its weak stability of the intermediate compound formed and prompt reaction rate compared with the previously reported chemically modified electrode (CME) systems. We think this type of achievement should be important for the basics of biosensors that rely on dehydrogenase enzymes.

  9. Predicting subcellular localization of proteins based on their N-terminal amino acid sequence.

    PubMed

    Emanuelsson, O; Nielsen, H; Brunak, S; von Heijne, G

    2000-07-21

    A neural network-based tool, TargetP, for large-scale subcellular location prediction of newly identified proteins has been developed. Using N-terminal sequence information only, it discriminates between proteins destined for the mitochondrion, the chloroplast, the secretory pathway, and "other" localizations with a success rate of 85% (plant) or 90% (non-plant) on redundancy-reduced test sets. From a TargetP analysis of the recently sequenced Arabidopsis thaliana chromosomes 2 and 4 and the Ensembl Homo sapiens protein set, we estimate that 10% of all plant proteins are mitochondrial and 14% chloroplastic, and that the abundance of secretory proteins, in both Arabidopsis and Homo, is around 10%. TargetP also predicts cleavage sites with levels of correctly predicted sites ranging from approximately 40% to 50% (chloroplastic and mitochondrial presequences) to above 70% (secretory signal peptides). TargetP is available as a web-server at http://www.cbs.dtu.dk/services/TargetP/.

  10. Acid-base-induced association of amino-terminated polystyrenes. 1. Linear chains and ring formation

    SciTech Connect

    Merkle, G.; Burchard, W.

    1992-05-14

    The associating coupling process of teritiary-amino-terminated polystyrene (PS) chains with monofunctional and bifunctional dinitrophenol reagents has been studied by means of UV-vis spectroscopy and light-scattering measurements as a function of polymer concentration. The mechanism of coupling was first checked with monofunctional PS chains. The equilibrium constants of the two functional groups of the coupler were found to be slightly different from each other; but with the same average values as for the monofunctional phenol compound. The increase of molecular weight agreed well with predictions from Flory`s theory. Much smaller weight average molecular weights were found, however, for the coupling of telechelic PS chains, and the deviations are stronger for the short chains than for the longer ones. The effect is explained by ring formation and three approximations were applied. These are (a) a mean field approximation, (b) the Jacobson-Stockmayer (JS) approach, and (c) the JS approach including excluded volume effect and its influence on Gaussian statistics. Molecular weights were also calculated from the weight fraction of rings and fitted to those obtained by LS where the effect bond length b was chosen to be the adjustable parameter. In the original JS treatment the effective bond length increased with the chain length of the primary chain. In treatment c this could be eliminated by consideration of excluded volume, but absolute values of b are unrealistically low. 50 refs., 8 figs., 3 tabs.

  11. Bioavailabilty of beta-amino acid and C-terminally derived PK/PBAN analogs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ability of linear beta amino-acid-substituted peptides (PK-betaA-1: Ac-YFT[beta3-P]RLa; PK-betaA-2: Ac-Y[beta2-homoF]TPRLa; PK-betaA-3: Ac-Y[beta3-F]TPRLa and PK-betaA-4: Ac-[beta3-F]FT[beta3-P]RLa) and unsubstituted analogs (Ac-YFTPRLa and YFTPRLa) of the pyrokinin(PK)/pheromone biosynthesis-ac...

  12. A C-Terminal Acidic Domain Regulates Degradation of the Transcriptional Coactivator Bob1

    PubMed Central

    Wong, Christina S. F.; Möller, Andreas

    2013-01-01

    Bob1 (Obf-1 or OCA-B) is a 34-kDa transcriptional coactivator encoded by the Pou2af1 gene that is essential for normal B-cell development and immune responses in mice. During lymphocyte activation, Bob1 protein levels dramatically increase independently of mRNA levels, suggesting that the stability of Bob1 is regulated. We used a fluorescent protein-based reporter system to analyze protein stability in response to genetic and physiological perturbations and show that, while Bob1 degradation is proteasome mediated, it does not require ubiquitination of Bob1. Furthermore, degradation of Bob1 in B cells appears to be largely independent of the E3 ubiquitin ligase Siah. We propose a novel mechanism of Bob1 turnover in B cells, whereby an acidic region in the C terminus of Bob1 regulates the activity of degron signals elsewhere in the protein. Changes that make the C terminus more acidic, including tyrosine phosphorylation-mimetic mutations, stabilize the instable murine Bob1 protein, indicating that B cells may regulate Bob1 stability and activity via signaling pathways. Finally, we show that expressing a stable Bob1 mutant in B cells suppresses cell proliferation and induces changes in surface marker expression commonly seen during B-cell differentiation. PMID:24061476

  13. Lysophosphatidic acid directly activates TRPV1 through a C-terminal binding site.

    PubMed

    Nieto-Posadas, Andrés; Picazo-Juárez, Giovanni; Llorente, Itzel; Jara-Oseguera, Andrés; Morales-Lázaro, Sara; Escalante-Alcalde, Diana; Islas, León D; Rosenbaum, Tamara

    2011-11-20

    Since 1992, there has been growing evidence that the bioactive phospholipid lysophosphatidic acid (LPA), whose amounts are increased upon tissue injury, activates primary nociceptors resulting in neuropathic pain. The TRPV1 ion channel is expressed in primary afferent nociceptors and is activated by physical and chemical stimuli. Here we show that in control mice LPA produces acute pain-like behaviors, which are substantially reduced in Trpv1-null animals. Our data also demonstrate that LPA activates TRPV1 through a unique mechanism that is independent of G protein-coupled receptors, contrary to what has been widely shown for other ion channels, by directly interacting with the C terminus of the channel. We conclude that TRPV1 is a direct molecular target of the pain-producing molecule LPA and that this constitutes, to our knowledge, the first example of LPA binding directly to an ion channel to acutely regulate its function.

  14. Involvement of Conserved Amino Acids in the C-Terminal Region of LINE-1 ORF2p in Retrotransposition.

    PubMed

    Christian, Claiborne M; Sokolowski, Mark; deHaro, Dawn; Kines, Kristine J; Belancio, Victoria P

    2017-03-01

    Long interspersed element 1 (L1) is the only currently active autonomous retroelement in the human genome. Along with the parasitic SVA and short interspersed element Alu, L1 is the source of DNA damage induced by retrotransposition: a copy-and-paste process that has the potential to disrupt gene function and cause human disease. The retrotransposition process is dependent upon the ORF2 protein (ORF2p). However, it is unknown whether most of the protein is important for retrotransposition. In particular, other than the Cys motif, the C terminus of the protein has not been intensely examined in the context of retrotransposition. Using evolutionary analysis and the Alu retrotransposition assay, we sought to identify additional amino acids in the C terminus important for retrotransposition. Here, we demonstrate that Gal4-tagged and untagged C-terminally truncated ORF2p fragments possess residual potential to drive Alu retrotransposition. Using sight-directed mutagenesis we identify that while the Y1180 amino acid is important for ORF2p- and L1-driven Alu retrotransposition, a mutation at this position improves L1 retrotransposition. Even though the mechanism of the contribution of Y1180 to Alu and L1 mobilization remains unknown, experimental evidence rules out its direct involvement in the ability of the ORF2p reverse transcriptase to generate complementary DNA. Additionally, our data support that ORF2p amino acids 1180 and 1250-1262 may be involved in the reported ORF1p-mediated increase in ORF2p-driven Alu retrotransposition.

  15. Molecular photovoltaic system based on fullerenes and carotenoids co-assembled in lipid/alkanethiol hybrid bilayers.

    PubMed

    Liu, Lixia; Zhan, Wei

    2012-03-13

    A hybrid molecular photovoltaic system, based on fullerene C(60) and lutein (a natural photosynthetic carotenoid pigment) that are assembled in a phospholipid/alkanethiol bilayer matrix, is described here. The assembly and photoconversion behaviors of such a system were studied by UV-vis spectroscopy, cyclic voltammetry, impedance spectroscopy, photoelectrochemical action spectroscopy, and photocurrent generation. While lutein itself is inefficient in generating photocurrent, it can strongly modulate photocurrents produced by fullerenes when coassembled in the lipid bilayer matrix presumably via photoinduced electron transfer. Our results thus provide a successful example of combining both synthetic and natural photoactive components in building molecular photovoltaic systems.

  16. A grazing incidence surface X-ray absorption fine structure (GIXAFS) study of alkanethiols adsorbed on Au, Ag, and Cu

    NASA Astrophysics Data System (ADS)

    Floriano, Pierre N.; Schlieben, Olaf; Doomes, Edward E.; Klein, Ingo; Janssen, J.; Hormes, Josef; Poliakoff, E. D.; McCarley, Robin L.

    2000-04-01

    Self-assembled monolayers of n-alkanethiols, CH 3-(CH 2) x-SH, on Au, Ag, and Cu have been studied with GIXAFS at the sulfur K-edge. For both pentanethiol and decanethiol monolayers on Ag and Cu, the three-fold hollow site is found to be the most probable sulfur binding site. However, observations for octadecanethiol indicate that the three-fold hollow site is not the exclusive binding site. In addition, the possible existence of disulfide bonds on the metal surface (adsorbed dialkyldisulfides) is not supported by the data. Preliminary results from monolayers on Au are also reported.

  17. Etchant-free graphene transfer using facile intercalation of alkanethiol self-assembled molecules at graphene/metal interfaces

    NASA Astrophysics Data System (ADS)

    Ohtomo, Manabu; Sekine, Yoshiaki; Wang, Shengnan; Hibino, Hiroki; Yamamoto, Hideki

    2016-06-01

    We report a novel etchant-free transfer method of graphene using the intercalation of alkanethiol self-assembled monolayers (SAMs) at the graphene/Cu interfaces. The early stage of intercalation proceeds through graphene grain boundaries or defects within a few seconds at room temperature until stable SAMs are formed after a few hours. The formation of SAMs releases the compressive strain of graphene induced by Cu substrates and make graphene slightly n-doped due to the formation of interface dipoles of the SAMs on metal surfaces. After SAM formation, the graphene is easily delaminated off from the metal substrates and transferred onto insulating substrates. The etchant-free process enables us to decrease the density of charged impurities and the magnitude of potential fluctuation in the transferred graphene, which suppress scattering of carriers. We also demonstrate the removal of alkanethiol SAMs and reuse the substrate. This method will dramatically reduce the cost of graphene transfer, which will benefit industrial applications such as of graphene transparent electrodes.We report a novel etchant-free transfer method of graphene using the intercalation of alkanethiol self-assembled monolayers (SAMs) at the graphene/Cu interfaces. The early stage of intercalation proceeds through graphene grain boundaries or defects within a few seconds at room temperature until stable SAMs are formed after a few hours. The formation of SAMs releases the compressive strain of graphene induced by Cu substrates and make graphene slightly n-doped due to the formation of interface dipoles of the SAMs on metal surfaces. After SAM formation, the graphene is easily delaminated off from the metal substrates and transferred onto insulating substrates. The etchant-free process enables us to decrease the density of charged impurities and the magnitude of potential fluctuation in the transferred graphene, which suppress scattering of carriers. We also demonstrate the removal of alkanethiol

  18. Amino acids in the COOH-terminal region of the oxytocin receptor third intracellular domain are important for receptor function.

    PubMed

    Zhong, Miao; Parish, Bridgette; Murtazina, Dilyara A; Ku, Chun-Ying; Sanborn, Barbara M

    2007-04-01

    Previously, residue K6.30 in the COOH-terminal region of the third intracellular domain (3iC) of the oxytocin (OT) receptor (OTR) was identified as important for receptor function leading to phospholipase C activation in both OTR and the vasopressin V(2) receptor (V(2)R) chimera V(2)ROTR3iC. Substitution of either A6.28K or V6.30K in wild-type V(2)R did not recapitulate the increase in phosphatidylinositide (PI) turnover observed in V(2)ROTR3iC. Hence, the role of K6.30 may be context-specific. Deletion of two NH(2)-terminal OTR3iC segments in the V(2)ROTR3iC chimera did not diminish vasopressin-stimulated PI turnover, whereas deletion of RVSSVKL (residues 6.19-6.25) reduced receptor expression. Deletion of this sequence in wild-type OTR reduced expression by 50% without affecting affinity for [(3)H]OT. This OTR mutant was unable to activate PI turnover or extracellular signal-regulated kinase 1/2 phosphorylation. The effects of alanine substitution for individual residues in RVSSVKL indicated differential importance for OTR function. The R6.19A substitution lost high-affinity sites for [(3)H]OT and the ability to stimulate PI turnover. Affinity for [(3)H]OT and membrane expression was not affected by any other substitutions. OTR-V6.20A and OTR-K6.24A mutants functioned as well as wild-type OTR, whereas OTR S6.21A, S6.22A, and V6.23A mutants exhibited impaired abilities to activate PI turnover (20-40% of OTR), and the OTR-L6.25A mutant exhibited constitutive activity. In conclusion, specific amino acids in the RVSSVKL segment in the COOH-terminal region of the third intracellular domain of OTR influence the ability of OTR to activate G protein-mediated actions.

  19. Purification and N-terminal amino acid sequence comparisons of structural proteins from retrovirus-D/Washington and Mason-Pfizer monkey virus.

    PubMed Central

    Henderson, L E; Sowder, R; Smythers, G; Benveniste, R E; Oroszlan, S

    1985-01-01

    A new D-type retrovirus originally designated SAIDS-D/Washington and here referred to as retrovirus-D/Washington (R-D/W) was recently isolated at the University of Washington Primate Center, Seattle, Wash., from a rhesus monkey with an acquired immunodeficiency syndrome and retroperitoneal fibromatosis. To better establish the relationship of this new D-type virus to the prototype D-type virus, Mason-Pfizer monkey virus (MPMV), we have purified and compared six structural proteins from each virus. The proteins purified from each D-type retrovirus include p4, p10, p12, p14, p27, and a phosphoprotein designated pp18 for MPMV and pp20 for R-D/W. Amino acid analysis and N-terminal amino acid sequence analysis show that the p4, p12, p14, and p27 proteins of R-D/W are distinct from the homologous proteins of MPMV but that these proteins from the two different viruses share a high degree of amino acid sequence homology. The p10 proteins from the two viruses have similar amino acid compositions, and both are blocked to N-terminal Edman degradation. The phosphoproteins from the two viruses each contain phosphoserine but are different from each other in amino acid composition, molecular weight, and N-terminal amino acid sequence. The data thus show that each of the R-D/W proteins examined is distinguishable from its MPMV homolog and that a major difference between these two D-type retroviruses is found in the viral phosphoproteins. The N-terminal amino acid sequences of D-type retroviral proteins were used to search for sequence homologies between D-type and other retroviral amino acid sequences. An unexpected amino acid sequence homology was found between R-D/W pp20 (a gag protein) and a 28-residue segment of the env precursor polyprotein of Rous sarcoma virus. The N-terminal amino acid sequences of the D-type major gag protein (p27) and the nucleic acid-binding protein (p14) show only limited amino acid sequence homology to functionally homologous proteins of C

  20. The Aquaporin Splice Variant NbXIP1;1α Is Permeable to Boric Acid and Is Phosphorylated in the N-terminal Domain

    PubMed Central

    Ampah-Korsah, Henry; Anderberg, Hanna I.; Engfors, Angelica; Kirscht, Andreas; Norden, Kristina; Kjellstrom, Sven; Kjellbom, Per; Johanson, Urban

    2016-01-01

    Aquaporins (AQPs) are membrane channel proteins that transport water and uncharged solutes across different membranes in organisms in all kingdoms of life. In plants, the AQPs can be divided into seven different subfamilies and five of these are present in higher plants. The most recently characterized of these subfamilies is the XIP subfamily, which is found in most dicots but not in monocots. In this article, we present data on two different splice variants (α and β) of NbXIP1;1 from Nicotiana benthamiana. We describe the heterologous expression of NbXIP1;1α and β in the yeast Pichia pastoris, the subcellular localization of the protein in this system and the purification of the NbXIP1;1α protein. Furthermore, we investigated the functionality and the substrate specificity of the protein by stopped-flow spectrometry in P. pastoris spheroplasts and with the protein reconstituted in proteoliposomes. The phosphorylation status of the protein and localization of the phosphorylated amino acids were verified by mass spectrometry. Our results show that NbXIP1;1α is located in the plasma membrane when expressed in P. pastoris, that it is not permeable to water but to boric acid and that the protein is phosphorylated at several amino acids in the N-terminal cytoplasmic domain of the protein. A growth assay showed that the yeast cells expressing the N-terminally His-tagged NbXIP1;1α were more sensitive to boric acid as compared to the cells expressing the C-terminally His-tagged isoform. This might suggest that the N-terminal His-tag functionally mimics the phosphorylation of the N-terminal domain and that the N-terminal domain is involved in gating of the channel. PMID:27379142

  1. The Aquaporin Splice Variant NbXIP1;1α Is Permeable to Boric Acid and Is Phosphorylated in the N-terminal Domain.

    PubMed

    Ampah-Korsah, Henry; Anderberg, Hanna I; Engfors, Angelica; Kirscht, Andreas; Norden, Kristina; Kjellstrom, Sven; Kjellbom, Per; Johanson, Urban

    2016-01-01

    Aquaporins (AQPs) are membrane channel proteins that transport water and uncharged solutes across different membranes in organisms in all kingdoms of life. In plants, the AQPs can be divided into seven different subfamilies and five of these are present in higher plants. The most recently characterized of these subfamilies is the XIP subfamily, which is found in most dicots but not in monocots. In this article, we present data on two different splice variants (α and β) of NbXIP1;1 from Nicotiana benthamiana. We describe the heterologous expression of NbXIP1;1α and β in the yeast Pichia pastoris, the subcellular localization of the protein in this system and the purification of the NbXIP1;1α protein. Furthermore, we investigated the functionality and the substrate specificity of the protein by stopped-flow spectrometry in P. pastoris spheroplasts and with the protein reconstituted in proteoliposomes. The phosphorylation status of the protein and localization of the phosphorylated amino acids were verified by mass spectrometry. Our results show that NbXIP1;1α is located in the plasma membrane when expressed in P. pastoris, that it is not permeable to water but to boric acid and that the protein is phosphorylated at several amino acids in the N-terminal cytoplasmic domain of the protein. A growth assay showed that the yeast cells expressing the N-terminally His-tagged NbXIP1;1α were more sensitive to boric acid as compared to the cells expressing the C-terminally His-tagged isoform. This might suggest that the N-terminal His-tag functionally mimics the phosphorylation of the N-terminal domain and that the N-terminal domain is involved in gating of the channel.

  2. Mechanistic studies of the immunochemical termination of self-tolerance with unnatural amino acids.

    PubMed

    Grünewald, Jan; Hunt, Grady S; Dong, Liqun; Niessen, Frank; Wen, Ben G; Tsao, Meng-Lin; Perera, Roshan; Kang, Mingchao; Laffitte, Bryan A; Azarian, Sassan; Ruf, Wolfram; Nasoff, Marc; Lerner, Richard A; Schultz, Peter G; Smider, Vaughn V

    2009-03-17

    For more than 2 centuries active immunotherapy has been at the forefront of efforts to prevent infectious disease [Waldmann TA (2003) Nat Med 9:269-277]. However, the decreased ability of the immune system to mount a robust immune response to self-antigens has made it more difficult to generate therapeutic vaccines against cancer or chronic degenerative diseases. Recently, we showed that the site-specific incorporation of an immunogenic unnatural amino acid into an autologous protein offers a simple and effective approach to overcome self-tolerance. Here, we characterize the nature and durability of the polyclonal IgG antibody response and begin to establish the generality of p-nitrophenylalanine (pNO(2)Phe)-induced loss of self-tolerance. Mutation of several surface residues of murine tumor necrosis factor-alpha (mTNF-alpha) independently to pNO(2)Phe leads to a T cell-dependent polyclonal and sustainable anti-mTNF-alpha IgG autoantibody response that lasts for at least 40 weeks. The antibodies bind multiple epitopes on mTNF-alpha and protect mice from severe endotoxemia induced by lipopolysaccharide (LPS) challenge. Immunization of mice with a pNO(2)Phe(43) mutant of murine retinol-binding protein (RBP4) also elicited a high titer IgG antibody response, which was cross-reactive with wild-type mRBP4. These findings suggest that this may be a relatively general approach to generate effective immunotherapeutics against cancer-associated or other weakly immunogenic antigens.

  3. Biosynthesis, glycosylation, and partial N-terminal amino acid sequence of the T-cell-activating protein TAP.

    PubMed Central

    Reiser, H; Coligan, J; Benacerraf, B; Rock, K L

    1987-01-01

    We have characterized the TAP molecule, an Ly-6 linked T-cell-activating glycoprotein. The three TAP bands that are precipitated from metabolically labeled cells display a common migration pattern in isoelectric focusing/NaDodSO4/PAGE gels and have common N-terminal sequences. This sequence is rich in cysteine and is homologous to that previously reported for the Ly-6.1E antigen. We, therefore, compared TAP and Ly-6.1E biochemically and found them to be structurally distinct. Given the role of TAP in T-cell activation, we further studied whether the molecule was phosphorylated. We have not found evidence for phosphorylation of the TAP protein. The carbohydrates present on the TAP molecule are resistant to peptide N-glycosidase F in vitro and tunicamycin in vivo. The upper band of the TAP triplet is susceptible to treatment with trifluoromethanesulfonic acid and thus seems to be of the O-linked rather than of the N-linked variety. The biosynthetic processing of TAP was studied in pulse-chase experiments. The middle band of the TAP triplet appears to be the earliest detectable species. Its conversion to the O-linked high molecular weight species can be blocked by monensin. Images PMID:3033645

  4. Biosynthesis, glycosylation, and partial N-terminal amino acid sequence of the T-cell-activating protein TAP

    SciTech Connect

    Reiser, H.; Coligan, J.; Benacerraf, B.; Rock, K.L.

    1987-05-01

    The authors have characterized the TAP molecule, an Ly-6 linked T-cell-activating glycoprotein. The three TAP bands that are precipitated from metabolically labeled cells display a common migration pattern in isoelectric focusing/NaDodSO/sub 4//PAGE gels and have common N-terminal sequences. This sequence is rich in cysteine and is homologous to that previously reported for the Ly-6.1E antigen. They therefore, compared TAP and Ly-6.1E biochemically and found them to be structurally distinct. Given the role of TAP in T-cell activation, they further studied whether the molecule was phosphorylated. We have not found evidence for phosphorylation of the TAP protein. The carbohydrates present on the TAP molecule are resistant to peptide N-glycosidase F in vitro and tunicamycin in vivo. The upper band of the TAP triplet is susceptible to treatment with trifluoromethanesulfonic acid and thus seems to be of the O-linked rather than of the N-linked variety. The biosynthetic processing of TAP was studied in pulse-chase experiments. The middle band of the TAP triplet appears to be the earliest detectable species. Its conversion to the O-linked high molecular weight species can be blocked by monensin.

  5. Development of an improved rhodium catalyst for z-selective anti-markovnikov addition of carboxylic acids to terminal alkynes.

    PubMed

    Wei, Siping; Pedroni, Julia; Meißner, Antje; Lumbroso, Alexandre; Drexler, Hans-Joachim; Heller, Detlef; Breit, Bernhard

    2013-09-02

    To develop more active catalysts for the rhodium-catalyzed addition of carboxylic acids to terminal alkynes furnishing anti-Markovnikov Z enol esters, a thorough study of the rhodium complexes involved was performed. A number of rhodium complexes were characterized by NMR, ESI-MS, and X-ray analysis and applied as catalysts for the title reaction. The systematic investigations revealed that the presence of chloride ions decreased the catalyst activity. Conversely, generating and applying a mixture of two rhodium species, namely, [Rh(DPPMP)2][H(benzoate)2] (DPPMP=diphenylphosphinomethylpyridine) and [{Rh(COD)(μ2-benzoate)}2], provided a significantly more active catalyst. Furthermore, the addition of a catalytic amount of base (Cs2CO3) had an additional accelerating effect. This higher catalyst activity allowed the reaction time to be reduced from 16 to 1-4 h while maintaining high selectivity. Studies on the substrate scope revealed that the new catalysts have greater functional-group compatibility.

  6. Gold Nanoparticles Decorated with Sialic Acid Terminated Bi‐antennary N‐Glycans for the Detection of Influenza Virus at Nanomolar Concentrations†

    PubMed Central

    Poonthiyil, Vivek; Nagesh, Prashanth T.; Husain, Matloob

    2015-01-01

    Abstract Gold nanoparticles decorated with full‐length sialic acid terminated complex bi‐antennary N‐glycans, synthesized with glycans isolated from egg yolk, were used as a sensor for the detection of both recombinant hemagglutinin (HA) and whole influenza A virus particles of the H1N1 subtype. Nanoparticle aggregation was induced by interaction between the sialic acid termini of the glycans attached to gold and the multivalent sialic acid binding sites of HA. Both dynamic light scattering (DLS) and UV/Vis spectroscopy demonstrated the efficiency of the sensor, which could detect viral HA at nanomolar concentrations and revealed a linear relationship between the extent of nanoparticle aggregation and the concentration of HA. UV/Vis studies also showed that these nanoparticles can selectively detect an influenza A virus strain that preferentially binds sialic acid terminated glycans with α(2→6) linkages over a strain that prefers glycans with terminal α(2→3)‐linked sialic acids. PMID:27308196

  7. A Mechanistic Study of a-Amino Acid-N-Carboxy Anhydride Polymerization: Comparing Initiation and Termination Events in High Vacuum and Traditional Polymerization Techniques

    SciTech Connect

    Pickel, Deanna L; Politakos, Nikolaos; Avgeropoulos, Apostolos; Messman, Jamie M

    2009-01-01

    High-vacuum polymerization of -amino acid-N-carboxyanhydride (NCAs) affords polymers with controlled molecular weights and narrow polydispersities, however a comprehensive study of the end-group composition of the resulting poly(amino acid)s has not yet been performed. This reveals crucial information, as the end-groups are indicative of both the polymerization mechanism (i.e., initiation event) as well as the termination pathways. To this end, poly(O-benzyl-L-tyrosine) initiated by 1,6-diaminohexane was synthesized and subsequently characterized by MALDI-TOF MS, NALDI -TOF MS and 13C NMR spectroscopy to ascertain the end-group structure. Polymers were prepared by both high vacuum and glove box techniques in DMF/THF. Preparation of poly(O-benzyl-L-tyrosine) by high vacuum techniques yielded a polymer initiated exclusively by the normal amine mechanism, and termination by reaction with DMF was observed. In contrast, polymers prepared in the glove box were initiated by the normal amine and activated monomer mechanisms, and several termination products are evident. To our knowledge, this is the first rigorous and comparative analysis of the end-group structure, and it demonstrates the advantage of high vacuum techniques for polymerization of NCAs for the preparation of well-defined poly(amino acid)s with end-group fidelity.

  8. Self-Assembled Monolayers of Dithiophosphinic Acids on Gold

    NASA Astrophysics Data System (ADS)

    San Juan, Ronan Roca

    This dissertation reports the synthesis of derivatives of dithiophosphinic acids (R1R2DTPAs), and the formation and characterization of DTPA SAMs on gold to build a knowledge base on their nature of binding, organization of the alkyl chains and electrochemical barrier properties. The binding of DTPA molecules on gold depends on the morphology of the gold film: They bind in a mixed monodentate and bidentate modes on standard as-deposited (As-Dep) gold, while they fully chelate on smoother template-stripped (TS) gold. Chapter 2 focuses on van der Waals interactions of various alkyl chain lengths of symmetrical R2DTPA SAMs, which increase with increasing chain lengths similar to those of the analogous n-alkanethiol SAMs, but with alkyl chains that are generally less dense than those of n-alkanethiol SAMs. Chapter 3 addresses why the DTPA compounds do not chelate on the standard As-Dep gold by comparing (C16)2DTPA SAM to (C16 )2DDP SAM. Here, side chain crystallinity stabilizes DTPA SAM structure at the expense of chelation of the DTPA molecules, which leads to a mixture of bidentate and monodentate DTPA molecules, whereas the increased flexibility of the chains in DDP due to the oxygen atoms retains chelation of the DDP molecules. Chapter 4 focuses on the SAMs formed from RlongRshort DTPAs, which shows that the length of the short chain spacer affects SAM packing density and thickness. The SAMs of these molecules also show homogeneous mixing of Rlong and Rshort chains. Chapter 5 investigates PhRDTPA SAMs in preparation for molecular junction studies. The chelation of PhRDTPA molecules on TS gold allows the PhRDTPAs to act as molecular alligator clips. The length of the alkyl chains controls the density of the phenyl group and they fill in the voids between adsorbates to prevent electrical shorting. Finally, Chapter 6 incorporates OH tail group(s) to control the wettability of DTPA SAMs. The presence of OH groups in DTPAs forms hydrophilic SAMs. The symmetrical OH-terminated

  9. Effects of changes in the interparticle separation induced by alkanethiols on the surface plasmon band and other properties of nanocrystalline gold films.

    PubMed

    Agrawal, Ved Varun; Varghese, Neenu; Kulkarni, G U; Rao, C N R

    2008-03-18

    Effects of changing the interparticle separation on the surface plasmon bands of ultrathin films of gold nanoparticles have been investigated by examining the interaction of alkanethiols of varying chain length on nanocrystalline gold films generated at the organic-aqueous interface. Adsorption of alkanethiols causes blue-shifts of the surface plasmon adsorption band, the magnitude of the shift being proportional to the chain length. The disordered nanocrystals thus created (lambdamax, 530 m) are in equilibrium with the ordered nanocrystals in the film (lambdamax, 700 m) as indicated by an isosbestic point around 600 nm. Long chain thiols disintegrate or disorder the gold films more effectively, as demonstrated by the increased population of the thiol-capped gold nanocrystals in solution. The rate of interaction of the thiols with the film decreases with the decreasing chain length. The effect of an alkanethiol on the spectrum of the gold film is specific, in that the effects with long and short chains are reversible. The changes in the plasmon band of gold due to interparticle separation can be satisfactorily modeled on the basis of the Maxwell-Garnett formalism. Spectroscopic studies, augmented by calorimetric measurements, suggest that the interaction of alkanethiols involves two steps, the first step being the exothermic gold film-thiol interaction and the second step includes the endothermic disordering process followed by further thiol capping of isolated gold particles.

  10. The use of alkanethiol self-assembled monolayers on 316L stainless steel for coronary artery stent nanomedicine applications: an oxidative and in vitro stability study.

    PubMed

    Mahapatro, Anil; Johnson, Dave M; Patel, Devang N; Feldman, Marc D; Ayon, Arturo A; Agrawal, C Mauli

    2006-09-01

    The use of self-assembled monolayers (SAMs) on medical devices offers a methodology for the incorporation of nanotechnology into medicine. SAMs are highly ordered nanosized molecular coatings, adding 1 to 10 nm thickness to a surface. This work is part of an overall goal to deliver therapeutic drugs from the surface of metal coronary stents using SAMs. In this study the oxidative and in vitro stability of functional alkylthiol SAMs on 316L stainless steel (SS) has been demonstrated. SAMs of 11-mercaptoundecanoic acid (-COOH SAM) and 11-mercapto-1-undecanol (-OH SAM) were formed on 316L SS. X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and contact angle (CA) measurements collectively confirmed the formation of functional alkylthiol SAMs on 316L SS. Well-formed SAMs (CA: 82 deg +/- 9 deg) were achieved within 48 hours of immersion in ethanolic solutions, after which no significant improvement in CA was observed. The ratio of the thiolate peak (163.5 eV) to the oxidized sulfur (sulfonates) peak (166.5 eV) gives us an indication of the percentage SAMs that would bind to the metal and serve as a drug reservoir in vivo; which in turn represents the stability and viability of these SAMs, keeping in mind the cardiovascular application under consideration. Oxidative and in vitro stability studies showed that alkanethiol SAMs oxidized completely within 14 days. The SAMs tend to desorb and leave the metal surface after longer time periods (21 days) in phosphate-buffered saline (PBS) immersion, whereas for oxidative exposure the SAMs continue to remain on the metal surface in the form of sulfonates. Although the chemistry of bonding of alkylthiol with the 316L SS is not well understood, the nanosized alkylthiol SAMs demonstrate sufficient stability to justify further study on these systems for potential in vivo drug delivery in the chosen coronary artery stent applications.

  11. Implications of terminal oxidase function in regulation of salicylic acid on soybean seedling photosynthetic performance under water stress.

    PubMed

    Tang, Yanping; Sun, Xin; Wen, Tao; Liu, Mingjie; Yang, Mingyan; Chen, Xuefei

    2017-03-01

    The aim of this study is to investigate whether exogenous application of salicylic acid (SA) could modulate the photosynthetic capacity of soybean seedlings in water stress tolerance, and to clarify the potential functions of terminal oxidase (plastid terminal oxidase (PTOX) and alternative oxidase (AOX)) in SA' s regulation on photosynthesis. The effects of SA and water stress on gas exchange, pigment contents, chlorophyll fluorescence, enzymes (guaiacol peroxidase (POD; EC 1.11.1.7), superoxide dismutase (SOD; EC 1.15.1.1), catalase (CAT; EC 1.11.1.6), ascorbate peroxidase (APX; EC 1.11.1.11) and NADP-malate dehydrogenase (NADP-MDH; EC1.1.1.82)) activity and transcript levels of PTOX, AOX1, AOX2a, AOX2b were examined in a hydroponic cultivation system. Results indicate that water stress significantly decreased the photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (E), pigment contents (Chla + b, Chla/b, Car), maximum quantum yield of PSⅡphotochemistry (Fv/Fm), efficiency of excitation capture of open PSⅡcenter (Fv'/Fm'), quantum efficiency of PSⅡphotochemistry (ΦPSⅡ), photochemical quenching (qP), and increased malondialdehyde (MDA) content and the activity of all the enzymes. SA pretreatment led to significant decreases in Ci and MDA content, and increases in Pn, Gs, E, pigment contents, Fv/Fm, Fv'/Fm', ΦPSⅡ, qP, and the activity of all the enzymes. SA treatment and water stress alone significantly up-regulated the expression of PTOX, AOX1 and AOX2b. SA pretreatment further increased the transcript levels of PTOX and AOX2b of soybean seedling under water stress. These results indicate that SA application alleviates the water stress-induced decrease in photosynthesis may mainly through maintaining a lower reactive oxygen species (ROS) level, a greater PSⅡefficiency, and an enhanced alternative respiration and chlororespiration. PTOX and AOX may play important roles in SA-mediated resistance to water stress.

  12. The N-terminal region of acyl-CoA synthetase 3 is essential for both the localization on lipid droplets and the function in fatty acid uptake.

    PubMed

    Poppelreuther, Margarete; Rudolph, Berenice; Du, Chen; Großmann, Regina; Becker, Melanie; Thiele, Christoph; Ehehalt, Robert; Füllekrug, Joachim

    2012-05-01

    Cytosolic lipid droplets (LDs) are storage organelles for neutral lipids derived from endogenous metabolism. Acyl-CoA synthetase family proteins are essential enzymes in this biosynthetic pathway, contributing activated fatty acids. Fluorescence microscopy showed that ACSL3 is localized to the endoplasmic reticulum (ER) and LDs, with the distribution dependent on the cell type and the supply of fatty acids. The N-terminus of ACSL3 was necessary and sufficient for targeting reporter proteins correctly, as demonstrated by subcellular fractionation and confocal microscopy. The N-terminal region of ACSL3 was also found to be functionally required for the enzyme activity. Selective permeabilization and in silico analysis suggest that ACSL3 assumes a hairpin membrane topology, with the N-terminal hydrophobic amino acids forming an amphipathic helix restricted to the cytosolic leaflet of the ER membrane. ACSL3 was effectively translocated from the ER to nascent LDs when neutral lipid synthesis was stimulated by the external addition of fatty acids. Cellular fatty acid uptake was increased by overexpression and reduced by RNA interference of ACSL3. In conclusion, the structural organization of ACSL3 allows the fast and efficient movement from the ER to emerging LDs. ACSL3 not only esterifies fatty acids with CoA but is also involved in the cellular uptake of fatty acids, presumably indirectly by metabolic trapping. The unique localization of the acyl-CoA synthetase ACSL3 on LDs suggests a function in the local synthesis of lipids.

  13. Quantification of glycated N-terminal peptide of hemoglobin using derivatization for multiple functional groups of amino acids followed by liquid chromatography/tandem mass spectrometry.

    PubMed

    Sakaguchi, Yohei; Kinumi, Tomoya; Yamazaki, Taichi; Takatsu, Akiko

    2016-02-01

    A novel method of amino acid analysis using derivatization of multiple functional groups (amino, carboxyl, and phenolic hydroxyl groups) was applied to measure glycated amino acids in order to quantify glycated peptides and evaluate the degree of glycation of peptide. Amino and carboxyl groups of amino acids were derivatized with 1-bromobutane so that the hydrophobicities and basicities of the amino acids, including glycated amino acids, were improved. These derivatized amino acids could be detected with high sensitivity using LC-MS/MS. In this study, 1-deoxyfructosyl-VHLTPE and VHLTPE, which are N-terminal peptides of the β-chains of hemoglobin, were selected as target compounds. After reducing the peptide sample solution with sodium borohydride, the obtained peptides were hydrolyzed with hydrochloric acid. The released amino acids were then derivatized with 1-bromobutane and analyzed with LC-MS/MS. The derivatized amino acids, including glycated amino acids, could be separated using an octadecyl silylated silica column and good sharp peaks were detected. We show a confirmatory experiment that the proposed method can be applied to evaluate the degree of glycation of peptides, using mixtures of glycated and non-glycated peptide.

  14. N-terminal amino acid sequences of D-serine deaminases of wild-type and operator-constitutive strains of Escherichia coli K-12.

    PubMed Central

    Heincz, M C; McFall, E

    1975-01-01

    The N-terminal amino acid sequences of the D-serine deaminases from strains of Escherichia coli K-12 that harbor wild-type and high-level constitutive catabolite-insensitive operator-initiator regions are identical: Met-Ser-GluNH2-Ser-Gly-Arg-His-Cys. This result indicates that the operator-initiator region is probably distinct from the D-serine deaminase structural gene. Images PMID:1099073

  15. Exploring molecular complexity with ALMA (EMoCA): Alkanethiols and alkanols in Sagittarius B2(N2)

    NASA Astrophysics Data System (ADS)

    Müller, Holger S. P.; Belloche, Arnaud; Xu, Li-Hong; Lees, Ronald M.; Garrod, Robin T.; Walters, Adam; van Wijngaarden, Jennifer; Lewen, Frank; Schlemmer, Stephan; Menten, Karl M.

    2016-03-01

    Context. Over the past five decades, radio astronomy has shown that molecular complexity is a natural outcome of interstellar chemistry, in particular in star forming regions. However, the pathways that lead to the formation of complex molecules are not completely understood and the depth of chemical complexity has not been entirely revealed. In addition, the sulfur chemistry in the dense interstellar medium is not well understood. Aims: We want to know the relative abundances of alkanethiols and alkanols in the Galactic center source Sagittarius B2(N2), the northern hot molecular core in Sgr B2(N), whose relatively small line widths are favorable for studying the molecular complexity in space. Methods: We investigated spectroscopic parameter sets that were able to reproduce published laboratory rotational spectra of ethanethiol and studied effects that modify intensities in the predicted rotational spectrum of ethanol. We used the Atacama Large Millimeter Array (ALMA) in its Cycles 0 and 1 for a spectral line survey of Sagittarius B2(N) between 84 and 114.4 GHz. These data were analyzed by assuming local thermodynamic equilibrium (LTE) for each molecule. Our observations are supplemented by astrochemical modeling; a new network is used that includes reaction pathways for alkanethiols for the first time. Results: We detected methanol and ethanol in their parent 12C species and their isotopologs with one 12C atom substituted by 13C; the latter were detected for the first time unambiguously in the case of ethanol. The 12C/13C ratio is ~25 for both molecules. In addition, we identified CH318 OH with a 16O/18O ratio of ~180 and a 13CH3OH/CH318 OH ratio of ~7.3. Upper limits were derived for the next larger alkanols normal- and iso-propanol. We observed methanethiol, CH3SH, also known as methyl mercaptan, including torsionally excited transitions for the first time. We also identified transitions of ethanethiol (or ethyl mercaptan), though not enough to claim a secure

  16. Image Potential States of Electrons Interacting with Roughened Metal Surfaces Coated with Self-Assembled Alkanethiol Monolayers

    NASA Astrophysics Data System (ADS)

    Clark, B. K.; Standard, J. M.; Gregory, Brian W.

    2000-03-01

    Electrons in image potential states (IPS) [1] have been a topic of great interest at smooth dielectric/metal interfaces [2]. IPSs at roughened dielectric/metal interfaces have recently been reported [3]. The IPS model is extended to the case of a charge interacting with two intersecting metal planes. We discuss the role of the angle between intersecting metal planes (characteristic of roughened surfaces) on the IPS binding energies for electrons interacting with these structures. Our results are applied to roughened gold surfaces coated with self-assembled alkanethiol monolayers. [1] T. Fauster, Applied Phys. A 59, 479, 1994. [2] N.-H. Ge, C. M. Wong, R. L. Lingle, Jr., J. D. McNeill, K. J. Gaffney, and C. B. Harris, Science 279, 202, 1998, for example. [3] B. K. Clark, B. W. Gregory, A. Avila, T. M. Cotton, and J. M. Standard, J. Phys. Chem. B 103, 8201, 1999.

  17. Electro-optic investigation of the n-alkanethiol GaAs(001) interface: Surface phenomena and applications to photoluminescence-based biosensing

    NASA Astrophysics Data System (ADS)

    Marshall, Gregory M.

    Semiconductor surfaces coupled to molecular structures derived from organic chemistry form the basis of an emerging class of field-effect devices. In addition to molecular electronics research, these interfaces are developed for a variety of sensor applications in the electronic and optical domains. Of practical interest are self-assembled monolayers (SAMs) comprised of n-alkanethiols [HS(CH2)n], which couple to the GaAs(001) surface through S-GaAs covalent bond formation. These SAMs offer potential functionality in terms of the requisite sensor chemistry and the passivation effect such coupling is known to afford. In this thesis, the SAM-GaAs interface is investigated in the context of a photonic biosensor based on photoluminescence (PL) variation. The scope of the work is categorized into three parts: i) the structural and compositional analysis of the surface using X-ray photoelectron spectroscopy (XPS), ii) the investigation of electronic properties at the interface under equilibrium conditions using infrared (IR) spectroscopy, the Kelvin probe method, and XPS, and iii) the analysis of the electro-optic response under steady-state photonic excitation, specifically, the surface photovoltage (SPV) and PL intensity. Using a partial overlayer model of angle-resolved XPS spectra in which the component assignments are shown to be quantitatively valid, the coverage fraction of methyl-terminated SAMs is shown to exceed 90%. Notable among the findings are a low-oxide, Ga-rich surface with elemental As present in sub-monolayer quantities consistent with theoretical surface morphologies. Modal analysis of transmission IR spectra show that the SAM molecular order is sufficient to support a Beer-Lambert determination of the IR optical constants, which yields the observation of a SAM-specific absorbance enhancement. By correlation of the IR absorbance with the SAM dipole layer potential, the enhancement mechanism is attributed to the vibrational moments added by the

  18. Abscisic Acid Flux Alterations Result in Differential Abscisic Acid Signaling Responses and Impact Assimilation Efficiency in Barley under Terminal Drought Stress1[C][W][OPEN

    PubMed Central

    Seiler, Christiane; Harshavardhan, Vokkaliga T.; Reddy, Palakolanu S.; Hensel, Götz; Kumlehn, Jochen; Eschen-Lippold, Lennart; Rajesh, Kalladan; Korzun, Viktor; Wobus, Ulrich; Lee, Justin; Selvaraj, Gopalan; Sreenivasulu, Nese

    2014-01-01

    Abscisic acid (ABA) is a central player in plant responses to drought stress. How variable levels of ABA under short-term versus long-term drought stress impact assimilation and growth in crops is unclear. We addressed this through comparative analysis, using two elite breeding lines of barley (Hordeum vulgare) that show senescence or stay-green phenotype under terminal drought stress and by making use of transgenic barley lines that express Arabidopsis (Arabidopsis thaliana) 9-cis-epoxycarotenoid dioxygenase (AtNCED6) coding sequence or an RNA interference (RNAi) sequence of ABA 8′-hydroxylase under the control of a drought-inducible barley promoter. The high levels of ABA and its catabolites in the senescing breeding line under long-term stress were detrimental for assimilate productivity, whereas these levels were not perturbed in the stay-green type that performed better. In transgenic barley, drought-inducible AtNCED expression afforded temporal control in ABA levels such that the ABA levels rose sooner than in wild-type plants but also subsided, unlike as in the wild type , to near-basal levels upon prolonged stress treatment due to down-regulation of endogenous HvNCED genes. Suppressing of ABA catabolism with the RNA interference approach of ABA 8′-hydroxylase caused ABA flux during the entire period of stress. These transgenic plants performed better than the wild type under stress to maintain a favorable instantaneous water use efficiency and better assimilation. Gene expression analysis, protein structural modeling, and protein-protein interaction analyses of the members of the PYRABACTIN RESISTANCE1/PYRABACTIN RESISTANCE1-LIKE/REGULATORY COMPONENT OF ABA RECEPTORS, TYPE 2C PROTEIN PHOSPHATASE Sucrose non-fermenting1-related protein kinase2, and ABA-INSENSITIVE5/ABA-responsive element binding factor family identified specific members that could potentially impact ABA metabolism and stress adaptation in barley. PMID:24610749

  19. The ABRF Edman Sequencing Research Group 2008 Study: Investigation into Homopolymeric Amino Acid N-Terminal Sequence Tags and Their Effects on Automated Edman Degradation

    PubMed Central

    Thoma, R. S.; Smith, J. S.; Sandoval, W.; Leone, J. W.; Hunziker, P.; Hampton, B.; Linse, K. D.; Denslow, N. D.

    2009-01-01

    The Edman Sequence Research Group (ESRG) of the Association of Biomolecular Resource designs and executes interlaboratory studies investigating the use of automated Edman degradation for protein and peptide analysis. In 2008, the ESRG enlisted the help of core sequencing facilities to investigate the effects of a repeating amino acid tag at the N-terminus of a protein. Commonly, to facilitate protein purification, an affinity tag containing a polyhistidine sequence is conjugated to the N-terminus of the protein. After expression, polyhistidine-tagged protein is readily purified via chelation with an immobilized metal affinity resin. The addition of the polyhistidine tag presents unique challenges for the determination of protein identity using Edman degradation chemistry. Participating laboratories were asked to sequence one protein engineered in three configurations: with an N-terminal polyhistidine tag; with an N-terminal polyalanine tag; or with no tag. Study participants were asked to return a data file containing the uncorrected amino acid picomole yields for the first 17 cycles. Initial and repetitive yield (R.Y.) information and the amount of lag were evaluated. Information about instrumentation and sample treatment was also collected as part of the study. For this study, the majority of participating laboratories successfully called the amino acid sequence for 17 cycles for all three test proteins. In general, laboratories found it more difficult to call the sequence containing the polyhistidine tag. Lag was observed earlier and more consistently with the polyhistidine-tagged protein than the polyalanine-tagged protein. Histidine yields were significantly less than the alanine yields in the tag portion of each analysis. The polyhistidine and polyalanine protein-R.Y. calculations were found to be equivalent. These calculations showed that the nontagged portion from each protein was equivalent. The terminal histidines from the tagged portion of the protein

  20. Deletion of the C-terminal 33 amino acids of cucumber mosaic virus movement protein enables a chimeric brome mosaic virus to move from cell to cell.

    PubMed Central

    Nagano, H; Okuno, T; Mise, K; Furusawa, I

    1997-01-01

    The movement protein (MP) gene of brome mosaic virus (BMV) was precisely replaced with that of cucumber mosaic virus (CMV). Infectivity tests of the chimeric BMV on Chenopodium quinoa, a permissive host for cell-to-cell movement of both BMV and CMV, showed that the chimeric BMV failed to move from cell to cell even though it replicated in protoplasts. A spontaneous mutant of the chimeric BMV that displayed cell-to-cell movement was subsequently obtained from a local lesion during one of the experiments. A cloned cDNA representing the genomic RNA encoding the MP of the chimeric BMV mutant was analyzed and found to contain a mutation in the CMV MP gene resulting in deletion of the C-terminal 33 amino acids of the MP. Directed mutagenesis of the CMV MP gene showed that the C-terminal deletion was responsible for the movement capability of the mutant. When the mutation was introduced into CMV, the CMV mutant moved from cell to cell in C. quinoa, though the movement was less efficient than that of the wild-type CMV. These results indicate that the CMV MP, except the C-terminal 33 amino acids, potentiates cell-to-cell movement of both BMV and CMV in C. quinoa. In addition, since C. quinoa is a common host for both BMV and CMV, these results suggest that the CMV MP has specificity for the viral genomes during cell-to-cell movement of the virus and that the C-terminal 33 amino acids of the CMV MP are involved in that specificity. PMID:9032362

  1. Role of the C-terminal basic amino acids and the lipid anchor of the Gγ2 protein in membrane interactions and cell localization.

    PubMed

    Noguera-Salvà, Maria A; Guardiola-Serrano, Francisca; Martin, M Laura; Marcilla-Etxenike, Amaia; Bergo, Martin O; Busquets, Xavier; Escribá, Pablo V

    2017-02-21

    Heterotrimeric G proteins are peripheral membrane proteins that frequently localize to the plasma membrane where their presence in molar excess over G protein coupled receptors permits signal amplification. Their distribution is regulated by protein-lipid interactions, which has a clear influence on their activity. Gβγ dimer drives the interaction between G protein heterotrimers with cell membranes. We focused our study on the role of the C-terminal region of the Gγ2 protein in G protein interactions with cell membranes. The Gγ2 subunit is modified at cysteine (Cys) 68 by the addition of an isoprenyl lipid, which is followed by the proteolytic removal of the last three residues that leaves an isoprenylated and carboxyl methylated Cys-68 as the terminal amino acid. The role of Cys isoprenylation of the CAAX box has been defined for other proteins, yet the importance of proteolysis and carboxyl methylation of isoprenylated proteins is less clear. Here, we showed that not only geranylgeranylation but also proteolysis and carboxyl methylation are essential for the correct localization of Gγ2 in the plasma membrane. Moreover, we showed the importance of electrostatic interactions between the inner leaflet of the plasma membrane and the positively charged C-terminal domain of the Gγ2 subunit (amino acids Arg-62, Lys-64 and Lys-65) as a second signal to reach the plasma membrane. Indeed, single or multiple point mutations at Gγ2 C-terminal amino acids have a significant effect on Gγ2 protein-plasma membrane interactions and its localization to charged Ld (liquid disordered) membrane microdomains. This article is part of a Special Issue entitled: Membrane Lipid Therapy: Drugs Targeting Biomembranes edited by Pablo Escríba-Ruíz.

  2. Terminal sequence importance of de novo proteins from binary-patterned library: stable artificial proteins with 11- or 12-amino acid alphabet.

    PubMed

    Okura, Hiromichi; Takahashi, Tsuyoshi; Mihara, Hisakazu

    2012-06-01

    Successful approaches of de novo protein design suggest a great potential to create novel structural folds and to understand natural rules of protein folding. For these purposes, smaller and simpler de novo proteins have been developed. Here, we constructed smaller proteins by removing the terminal sequences from stable de novo vTAJ proteins and compared stabilities between mutant and original proteins. vTAJ proteins were screened from an α3β3 binary-patterned library which was designed with polar/ nonpolar periodicities of α-helix and β-sheet. vTAJ proteins have the additional terminal sequences due to the method of constructing the genetically repeated library sequences. By removing the parts of the sequences, we successfully obtained the stable smaller de novo protein mutants with fewer amino acid alphabets than the originals. However, these mutants showed the differences on ANS binding properties and stabilities against denaturant and pH change. The terminal sequences, which were designed just as flexible linkers not as secondary structure units, sufficiently affected these physicochemical details. This study showed implications for adjusting protein stabilities by designing N- and C-terminal sequences.

  3. Characterization of N-terminal amino group-heme ligation emerging upon guanidine hydrochloric acid induced unfolding of Hydrogenobacter thermophilus ferricytochrome c552.

    PubMed

    Tai, Hulin; Kawano, Shin; Yamamoto, Yasuhiko

    2008-01-01

    Nonnative heme coordination structures emerging upon guanidine hydrochloric acid (GdnHCl) induced unfolding of Hydrogenobacter thermophilus ferricytochrome c552 were characterized by means of paramagnetic NMR. The heme coordination structure possessing the N-terminal amino group of the peptide chain in place of axial Met (His-Nterm form) was determined in the presence of GdnHCl concentrations in excess of 1.5 M at neutral pH. The stability of the His-Nterm form at pH 7.0 was found to be comparable with that of the bis-His form which has been recognized as a major nonnative heme coordination structure in cytochrome c folding/unfolding. Consequently, in addition to the bis-His form, the His-Nterm form is a substantial intermediate which affects the pathway and kinetics of the folding/unfolding of cytochromes c, of which the N-terminal amino groups are not acetylated.

  4. Isolation and characterization of Exodus-2, a novel C-C chemokine with a unique 37-amino acid carboxyl-terminal extension.

    PubMed

    Hromas, R; Kim, C H; Klemsz, M; Krathwohl, M; Fife, K; Cooper, S; Schnizlein-Bick, C; Broxmeyer, H E

    1997-09-15

    Chemokines are a group of small, homologous proteins that regulate leukocyte migration, hemopoiesis, and HIV-1 absorption. We report here the cloning and characterization of a novel murine and human C-C chemokine termed Exodus-2 for its similarity to Exodus-1/MIP-3alpha/LARC, and its chemotactic ability. This novel chemokine has a unique 36 or 37 (murine and human, respectively) amino acid carboxyl-terminal extension not seen in any other chemokine family member. Purified recombinant Exodus-2 was found to have two activities classically associated with chemokines: inhibiting hemopoiesis and stimulating chemotaxis. However, Exodus-2 also had unusual characteristics for C-C chemokines. It selectively stimulated the chemotaxis of T-lymphocytes and was preferentially expressed in lymph node tissue. The combination of these characteristics may be a functional correlate for the unique carboxyl-terminal structure of Exodus-2.

  5. Effects of salt, polyethylene glycol, and locked nucleic acids on the thermodynamic stabilities of consecutive terminal adenosine mismatches in RNA duplexes.

    PubMed

    Gu, Xiaobo; Nguyen, Mai-Thao; Overacre, Abigail; Seaton, Samantha; Schroeder, Susan J

    2013-04-04

    Consecutive terminal mismatches add thermodynamic stability to RNA duplexes and occur frequently in microRNA-mRNA interactions. Accurate thermodynamic stabilities of consecutive terminal mismatches contribute to the development of specific, high-affinity siRNA therapeutics. Consecutive terminal adenosine mismatches (TAMS) are studied at different salt concentrations, with polyethylene glycol cosolutes, and with locked nucleic acid (LNA) substitutions. These measurements provide benchmarks for the application of thermodynamic predictions to different physiological or therapeutic conditions. The salt dependence for RNA duplex stability is similar for TAMS, internal loops, and Watson-Crick duplexes. A unified model for predicting the free energy of an RNA duplex with or without loops and mismatches at lower sodium concentrations is presented. The destabilizing effects of PEG 200 are larger for TAMS than internal loops or Watson-Crick duplexes, which may result from different base stacking conformations, dynamics, and water hydration. In contrast, LNA substitutions stabilize internal loops much more than TAMS. Surprisingly, the average per adenosine increase in stability for LNA substitutions in internal loops is -1.82 kcal/mol and only -0.20 kcal/mol for TAMS. The stabilities of TAMS and internal loops with LNA substitutions have similar favorable free energies. Thus, the unfavorable free energy of adenosine internal loops is largely an entropic effect. The favorable stabilities of TAMS result mainly from base stacking. The ability of RNA duplexes to form extended terminal mismatches in the absence of proteins such as argonaute and identifying the enthalpic contributions to terminal mismatch stabilities provide insight into the physical basis of microRNA-mRNA molecular recognition and specificity.

  6. Terminal sialic acid linkages determine different cell infectivities of human parainfluenza virus type 1 and type 3.

    PubMed

    Fukushima, Keijo; Takahashi, Tadanobu; Ito, Seigo; Takaguchi, Masahiro; Takano, Maiko; Kurebayashi, Yuuki; Oishi, Kenta; Minami, Akira; Kato, Tatsuya; Park, Enoch Y; Nishimura, Hidekazu; Takimoto, Toru; Suzuki, Takashi

    2014-09-01

    Human parainfluenza virus type 1 (hPIV1) and type 3 (hPIV3) initiate infection by sialic acid binding. Here, we investigated sialic acid linkage specificities for binding and infection of hPIV1 and hPIV3 by using sialic acid linkage-modified cells treated with sialidases or sialyltransferases. The hPIV1 is bound to only α2,3-linked sialic acid residues, whereas hPIV3 is bound to α2,6-linked sialic acid residues in addition to α2,3-linked sialic acid residues in human red blood cells. α2,3 linkage-specific sialidase treatment of LLC-MK2 cells and A549 cells decreased the infectivity of hPIV1 but not that of hPIV3. Treatment of A549 cells with α2,3 linkage-specific sialyltransferase increased infectivities of both hPIV1 and hPIV3, whereas α2,6 linkage-specific sialyltransferase treatment increased only hPIV3 infectivity. Clinical isolates also showed similar sialic acid linkage specificities. We concluded that hPIV1 utilizes only α2,3 sialic acid linkages and that hPIV3 makes use of α2,6 sialic acid linkages in addition to α2,3 sialic acid linkages as viral receptors.

  7. Termination Documentation

    ERIC Educational Resources Information Center

    Duncan, Mike; Hill, Jillian

    2014-01-01

    In this study, we examined 11 workplaces to determine how they handle termination documentation, an empirically unexplored area in technical communication and rhetoric. We found that the use of termination documentation is context dependent while following a basic pattern of infraction, investigation, intervention, and termination. Furthermore,…

  8. Excited state electron distribution and role of the terminal amine in acidic and basic tryptophan dipeptide fluorescence

    NASA Astrophysics Data System (ADS)

    Eisenberg, Azaria S.; Nathan, Moshe; Juszczak, Laura J.

    2016-08-01

    The results of quantum yield (QY) study of tryptophanyl glutamate (Trp-Glu), tryptophanyl lysine (Trp-Lys) and lysinyl tryptophan (Lys-Trp) dipeptides over the pH range, 1.5-13, show that the charge state of the N-terminal amine, and not the nominal molecular charge determines the QY. When the terminal amine is protonated, QY is low (10-2) for all three dipeptides. As the terminal amine cation is found proximal to the indole ring in Trp-Glu and Trp-Lys conformers but not in those for Lys-Trp, its effect may lie only in the partitioning of energy between nonradiative processes, not on QY reduction. QY is also low when both the N-terminal amine and indole amine are deprotonated. These two low QY states can be distinguished by fluorescence lifetime measurement. Molecular dynamics simulation shows that the Chi 1 conformers persist for tens of nanoseconds such that 100-101 ns lifetimes may be associated with individual Chi 1 conformers. The ground state electron density or isosurface of high QY (0.30) 3-methyindole has a uniform electron density over the indole ring as do the higher QY Trp dipeptide conformers. This validates the association of ground state isosurfaces with QY. Excited state orbitals from calculated high intensity, low energy absorption transitions are typically centered over the indole ring for higher QY dipeptide species and off the ring in lower QY species. Thus excited state orbitals substantiate the earlier finding that the ground state isosurface charge density pattern on the indole ring can be predictive of QY.

  9. Targeting of proConA to the plant vacuole depends on its nine amino-acid C-terminal propeptide.

    PubMed

    Saint-Jore-Dupas, Claude; Claude, Saint-Jore-Dupas; Gilbert, Marie-Agnès; Marie-Agnès, Gilbert; Ramis, Catalina; Catalina, Ramis; Paris, Nadine; Nadine, Paris; Kiefer-Meyer, Marie-Christine; Marie-Christine, Kiefer-Meyer; Neuhaus, Jean-Marc; Jean-Marc, Neuhaus; Faye, Loïc; Loïc, Faye; Gomord, Véronique; Véronique, Gomord

    2005-10-01

    Concanavalin A (ConA) is a well characterized and extensively used lectin accumulated in the protein bodies of jack bean cotyledons. ConA is synthesized as an inactive precursor proConA. The maturation of inactive proConA into biologically active ConA is a complex process including the removal of an internal glycopeptide and a C-terminal propeptide (CTPP), followed by a head-to-tail ligation of the two largest polypeptides. The cDNA encoding proConA was cloned and expressed in tobacco BY-2 cells. ProConA was slowly transported to the vacuole where its maturation into ConA was similar to that in jack bean cotyledons, apart from an incomplete final ligation. To investigate the role of the nine amino acid CTPP, a truncated form lacking the propeptide (proConADelta9) was expressed in BY-2 cells. In contrast to proConA, proConADelta9 was rapidly chased out of the endoplasmic reticulum (ER) and secreted into the culture medium. The CTPP was then fused to the C-terminal end of a secreted form of green fluorescent protein (secGFP). When expressed in tobacco BY-2 cells and leaf protoplasts, the chimaeric protein was located in the vacuole whereas secGFP was located in the culture medium and in the vacuole. Altogether, our results show we have isolated a new C-terminal vacuolar sorting determinant.

  10. The characterization of Mycoplasma synoviae EF-Tu protein and proteins involved in hemadherence and their N-terminal amino acid sequences.

    PubMed

    Bencina, D; Narat, M; Dovc, P; Drobnic-Valic, M; Habe, F; Kleven, S H

    1999-04-01

    An abundant cytoplasmic 43-kDa protein from Mycoplasma synoviae, a major pathogen from poultry, was identified as elongation factor Tu. The N-terminal amino acid sequence (AKLDFDRSKEHVNVGTIGHV) has 90% identity with the sequence of the Mycoplasma hominis elongation factor Tu protein. Monoclonal antibodies reacting with the M. synoviae elongation factor Tu protein also reacted with 43-kDa proteins from the avian Mycoplasma species Mycoplasma gallinarum, Mycoplasma gallinaceum, Mycoplasma pullorum, Mycoplasma cloacale, Mycoplasma iners and Mycoplasma meleagridis, but not with the proteins from Mycoplasma gallisepticum, Mycoplasma imitans or Mycoplasma iowae. In addition, two groups of phase variable integral membrane proteins, pMSA and pMSB, associated with hemadherence and pathogenicity of M. synoviae strains AAY-4 and ULB925 were identified. The cleavage of a larger hemagglutinating protein encoded by a gene homologous to the vlhA gene of M. synoviae generates pMSB1 and pMSA1 proteins defined by mAb 125 and by hemagglutination inhibiting mAb 3E10, respectively. The N-terminal amino acid sequences of pMSA proteins (SENKLI ... and SENETQ ...) probably indicate the cleavage site of the M. synoviae strain ULB 925 hemagglutinin.

  11. Identification of amino acids inserted during suppression of UAA and UGA termination codons at the gag-pol junction of Moloney murine leukemia virus.

    PubMed Central

    Feng, Y X; Copeland, T D; Oroszlan, S; Rein, A; Levin, J G

    1990-01-01

    Expression of the murine leukemia virus pol gene occurs by translational readthrough of an in-frame UAG codon between the gag and pol coding regions. In a previous study, we mutated the UAG codon to UAA or UGA and demonstrated that both of these termination codons could be suppressed in reticulocyte lysates and in infected cells with the same efficiency as UAG. We now report the identity of the amino acids inserted in vitro in response to UAA and UGA in fusion products containing the gag-pol junction region. The results show that UAA, like UAG, directs the incorporation of glutamine, whereas UGA directs the incorporation of three amino acids, arginine, cysteine, and tryptophan. To our knowledge, this is the first report indicating misreading of UAA as glutamine and UGA as arginine and cysteine in higher eukaryotes. Interestingly, although our protein synthesis system presumably contains other known UAG and UGA suppressors, these tRNAs did not suppress the termination codons in our experiments. Thus, it seems possible that the sequence surrounding the gag-pol junction not only promotes suppression but also helps determine which tRNAs function in suppression. Images PMID:2247457

  12. Phenylethynyl terminated imide oligomers

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M. (Inventor); Bryant, Robert G. (Inventor); Jensen, Brian J. (Inventor); Havens, Stephen J. (Inventor)

    1995-01-01

    Four phenylethynyl amine compounds - 3 and 4-aminophenoxy-4'-phenylethynylbenzophenone, and 3 and 4-amino-4'-phenylethynylbenzophenone - were readily prepared and were used to endcap imide oligomers. Phenylethynyl-terminated amide acid oligomers and phenylethynyl-terminated imide oligomers with various molecular weights and compositions were prepared and characterized. These oligomers were cured at 300 to 400 C to provide crosslinked polyimides with excellent solvent resistance, high strength and modulus, and good high temperature properties. Adhesive panels, composites, films, and moldings from these phenylethynyl terminated imide oligomers gave excellent mechanical performance.

  13. Niflumic acid-induced increase in potassium currents in frog motor nerve terminals: effects on transmitter release.

    PubMed

    Miralles, F; Marsal, J; Peres, J; Solsona, C

    1996-04-01

    The actions of the nonsteroidal antiinflammatory drug niflumic acid were studied on frog neuromuscular preparations by conventional electrophysiological techniques. Niflumic acid reduced the amplitude and increased the latency of endplate potentials in a concentration-dependent manner. Neuromuscular junctions pretreated with niflumic acid (0.05-0.5 mM) showed much less depression than control when they were stimulated with trains of impulses. Inhibition of acetylcholine release was reverted by raising the extracellular Ca(2+) concentration but not by simply washing out the preparations with niflumic acid-free solutions. Pretreatment with indomethacin (0.1 mM), another nonsteroidal antiinflammatory drug, did not affect the niflumic acid-induced inhibition of evoked responses. Niflumic acid (0.1 mM) did not change the amplitude of miniature endplate potentials and had a dual action on the frequency of miniatures: it decreased their frequency at 0.1 mM whereas it produced an enormous increase in the rate of spontaneous discharge at 0.5 mM. Niflumic acid (0.1 - 1 mM) reversibly increased the amplitude and affected the kinetics of presynaptic voltage-activated K+ current and Ca(2+)-activated K(+) current in a concentration-dependent manner. Niflumic acid (0.1 - 1 mM) irreversibly decreased the amplitude and reversibly affected the kinetics of the nodal Na(+) current. Indomethacin (0.1 mM) had no effect on presynaptic currents. In conclusion, niflumic acid reduces acetylcholine release by increasing presynaptic K+ currents. This may shorten the depolarizing phase of the presynaptic action potential and may reduce the entry of Ca(2+) with each impulse.

  14. Fluorinated and Charged Hydrogenated Alkanethiolates Grafted on Gold: Expanding the Diversity of Mixed-Monolayer Nanoparticles for Biological Applications.

    PubMed

    Bidoggia, Silvia; Milocco, Francesca; Polizzi, Stefano; Canton, Patrizia; Saccani, Alessandra; Sanavio, Barbara; Krol, Silke; Stellacci, Francesco; Pengo, Paolo; Pasquato, Lucia

    2017-01-18

    Low intrinsic toxicity, high solubility, and stability are important and necessary features of gold nanoparticles to be used in the biomedical field. In this context, charged nanoparticles proved to be very versatile, and among them charged mixed-monolayer gold nanoparticles, displaying monolayers with well-defined morphologies, represent a paradigm. By using mixtures of hydrogenated and fluorinated thiols, the formation of monolayer domains may be brought to an extreme because of the immiscibility of fluorinated and hydrogenated chains. Following this rationale, mixed monolayer gold nanoparticles featuring ammonium, sulfonate, or carboxylic groups on their surface were prepared by using amphiphilic hydrogenated thiols and 1H,1H,2H,2H-perfluoro-alkanethiols. The toxicity of these systems was assessed in HeLa cells and was found to be, in general, low even for the cationic nanoparticles which usually show a high cytotoxicity and is comparable to that of homoligand gold nanoparticles displaying amphiphilic-charge neutral-hydrogenated or fluorinated thiolates in their monolayer. These properties make the mixed ligand monolayer gold nanoparticles an interesting new candidate for medical application.

  15. A pH-Sensitive Supramolecular Switch Based on Mixed Carboxylic Acid Terminated Self-Assembled Monolayers on Au(111).

    PubMed

    Jacquelín, Daniela K; Pérez, Manuel A; Euti, Esteban M; Arisnabarreta, Nicolás; Cometto, Fernando P; Paredes-Olivera, Patricia; Patrito, E Martín

    2016-02-02

    We show that homogeneously mixed self-assembled monolayers (SAMs) of mercaptoalkanoic acids of different chain lengths can be used to build up a pH-sensitive supramolecular switch. The acids with short and long alkyl chains interact via the strong hydrogen bond between carboxylic acid groups. The pH acts as a trigger by breaking or restoring the hydrogen bond interaction in basic or acidic solutions, respectively. The corresponding changes in the monolayer structure were determined by ellipsometry, surface-enhanced Raman spectroscopy, and contact angle measurements. Density functional theory (DFT) calculations were performed to elucidate the structures of interacting molecules compatible with the surface coverage obtained from electrochemical reductive desorption experiments. The simplicity of the preparation procedure assures a high reproducibility whereas the stability of the homogeneous mixed SAM guarantees the reversibility of the switching process.

  16. Synthesis of Met-enkephalin by solution-phase peptide synthesis methodology utilizing para-toluene sulfonic acid as N-terminal masking of l-methionine amino acid.

    PubMed

    Khan, Riaz A

    2016-12-01

    The Met-enkephalin, Tyr-Gly-Gly-Phe-Met, was synthesized by the solution-phase synthesis (SPS) methodology employing -OBzl group as carboxyls' protection, while the t-Boc groups were employed for the N-terminal α-amines' protection for the majority of the amino acids of the pentapeptide sequence. The l-methionine (l-Met) amino acid was used as PTSA.Met-OBzl obtained from the simultaneous protection of the α-amino, and carboxyl group with para-toluene sulfonic acid (PTSA) and as-OBzl ester, respectively in a C-terminal start of the 2 + 2 + 1 fragments condensation convergent synthetic approach. The protection strategy provided a short, single-step, simultaneous, orthogonal, nearly quantitative, robust, and stable process to carry through the protected l-methionine and l-phenylalanine coupling without any structural deformities during coupling and workups. The structurally confirmed final pentapeptide product was feasibly obtained in good yields through the current approach.

  17. Hypergravity exposure decreases gamma-aminobutyric acid immunoreactivity in axon terminals contacting pyramidal cells in the rat somatosensory cortex: a quantitative immunocytochemical image analysis

    NASA Technical Reports Server (NTRS)

    D'Amelio, F.; Wu, L. C.; Fox, R. A.; Daunton, N. G.; Corcoran, M. L.; Polyakov, I.

    1998-01-01

    Quantitative evaluation of gamma-aminobutyric acid immunoreactivity (GABA-IR) in the hindlimb representation of the rat somatosensory cortex after 14 days of exposure to hypergravity (hyper-G) was conducted by using computer-assisted image processing. The area of GABA-IR axosomatic terminals apposed to pyramidal cells of cortical layer V was reduced in rats exposed to hyper-G compared with control rats, which were exposed either to rotation alone or to vivarium conditions. Based on previous immunocytochemical and behavioral studies, we suggest that this reduction is due to changes in sensory feedback information from muscle receptors. Consequently, priorities for muscle recruitment are altered at the cortical level, and a new pattern of muscle activity is thus generated. It is proposed that the reduction observed in GABA-IR of the terminal area around pyramidal neurons is the immunocytochemical expression of changes in the activity of GABAergic cells that participate in reprogramming motor outputs to achieve effective movement control in response to alterations in the afferent information.

  18. Ischemia-Modified Albumin as a Marker of Acute Coronary Syndrome: The Case for Revising the Concept of "N-Terminal Modification" to "Fatty Acid Occupation" of Albumin.

    PubMed

    Oran, Ismail; Oran, Bulent

    2017-01-01

    Ischemia-modified albumin (IMA) is assumed "N-terminal modified" albumin which is generated immediately following myocardial ischemia. The diagnosis of IMA is based on reduced cobalt binding affinity to albumin which is attributed mainly to incapability of cobalt to bind at albumin's modified N-terminus. Although the albumin cobalt binding test was accepted as a potentially powerful marker for discriminating acute coronary syndrome from nonischemic chest pain, its usefulness has been brought into question in recent years. Patients with acutely ischemic myocardium exhibit a rapid increase in serum levels of fatty acids (FAs). Almost all released FAs are strongly bound to albumin which create conformational changes in the protein with resultant reduced cobalt binding affinity. There is a clear metabolic and temporal relationship between IMA measured via albumin cobalt binding testing and serum levels of FAs. In line with what has been suggested recently in the literature, we conclude that a shift from the concept of "N-terminal modified" to "FA-occupied" albumin is required, as this better describes IMA in patients with acute coronary syndrome. We also offer "oxidation modified albumin, OMA," which is conceptually different from the "FA-occupied" IMA, to describe modification of albumin in chronic disease associated with increased oxidative stress.

  19. Synthesis of vinyl-terminated Au nanoprisms and nanooctahedra mediated by 3-butenoic acid: direct Au@pNIPAM fabrication with improved SERS capabilities

    NASA Astrophysics Data System (ADS)

    Casado-Rodriguez, M. A.; Sanchez-Molina, M.; Lucena-Serrano, A.; Lucena-Serrano, C.; Rodriguez-Gonzalez, B.; Algarra, M.; Diaz, A.; Valpuesta, M.; Lopez-Romero, J. M.; Perez-Juste, J.; Contreras-Caceres, R.

    2016-02-01

    Here we describe the first seedless synthesis of vinyl-terminated Au nanotriangular prisms (AuNTPs) and nanooctahedra (AuNOC) in aqueous media. This synthesis is performed by chemical reduction of chloroauric acid (HAuCl4) with 3-butenoic acid (3BA) in the presence of benzyldimethylammonium chloride (BDAC). The principal novelties of the presented method are the use of a mixture of 3BA and BDAC, the synthesis of gold prisms and octahedra with controllable size, and the presence of terminal double bonds on the metal surface. Initially this method produces a mixture of triangular gold nanoprisms and octahedra; however, both morphologies are successfully separated by surfactant micelle induced depletion interaction, reaching percentages up to ~90%. Moreover, the alkene moieties present on the gold surface are exploited for the fabrication of hybrid core@shell particles. Gold octahedra and triangular prisms are easily encapsulated by free radical polymerization of N-isopropylacrylamide (NIPAM). Finally, in order to obtain a gold core with the most number of tips, AuNTP@pNIPAM microgels were subjected to gold core overgrowth, thus resulting in star-shaped nanoparticles (AuSTs@pNIPAM). We use 4-amino-benzenethiol as the model analyte for SERS investigations. As expected, gold cores with tips and high curvature sites produced the highest plasmonic responses.Here we describe the first seedless synthesis of vinyl-terminated Au nanotriangular prisms (AuNTPs) and nanooctahedra (AuNOC) in aqueous media. This synthesis is performed by chemical reduction of chloroauric acid (HAuCl4) with 3-butenoic acid (3BA) in the presence of benzyldimethylammonium chloride (BDAC). The principal novelties of the presented method are the use of a mixture of 3BA and BDAC, the synthesis of gold prisms and octahedra with controllable size, and the presence of terminal double bonds on the metal surface. Initially this method produces a mixture of triangular gold nanoprisms and octahedra; however

  20. Structure and homogeneity of pseudo-physiological phospholipid bilayers and their deposition characteristics on carboxylic acid terminated self-assembled monolayers.

    PubMed

    Mechler, Adam; Praporski, Slavica; Piantavigna, Stefania; Heaton, Steven M; Hall, Kristopher N; Aguilar, Marie-Isabel; Martin, Lisandra L

    2009-02-01

    Supported phospholipid bilayers are frequently used to establish a pseudo-physiological environment required for the study of protein function or the design of enzyme-based biosensors and biocatalytic reactors. These membranes are deposited from bilayer vesicles (liposomes) that rupture and fuse into a planar membrane upon adhesion to a surface. However, the morphology and homogeneity of the resulting layer is affected by the characteristics of the precursor liposome suspension and the substrate. Here we show that two distinct liposome populations contribute to membrane formation--equilibrium liposomes and small unilamellar vesicles. Liposome deposition onto carboxylic acid terminated self-assembled monolayers resulted in planar mono- and multilayer, vesicular and composite membranes, as a function of liposome size and composition. Quartz crystal microbalance data provided estimates for layer thicknesses and sheer moduli and were used for classification of the final structure. Finally, atomic force microscopy data illustrated the inherently inhomogeneous and dynamic nature of these membranes.

  1. Truncation of the MSH2 C-terminal 60 amino acids disrupts effective DNA mismatch repair and is causative for Lynch syndrome.

    PubMed

    Wielders, Eva; Delzenne-Goette, Elly; Dekker, Rob; van der Valk, Martin; Te Riele, Hein

    2017-04-01

    Missense variants of DNA mismatch repair (MMR) genes pose a problem in clinical genetics as long as they cannot unambiguously be assigned as the cause of Lynch syndrome (LS). To study such variants of uncertain clinical significance, we have developed a functional assay based on direct measurement of MMR activity in mouse embryonic stem cells expressing mutant protein from the endogenous alleles. We have applied this protocol to a specific truncation mutant of MSH2 that removes 60 C-terminal amino acids and has been found in suspected LS families. We show that the stability of the MSH2/MSH6 heterodimer is severely perturbed, causing attenuated MMR in in vitro assays and cancer predisposition in mice. This mutation can therefore unambiguously be considered as deleterious and causative for LS.

  2. c-Jun N-terminal Kinase (JNK) induces phosphorylation of amyloid precursor protein (APP) at Thr668, in okadaic acid-induced neurodegeneration

    PubMed Central

    Ahn, Ji-Hwan; So, Sang-Pil; Kim, Na-Young; Kim, Hyun-Ju; Yoon, Seung-Yong; Kim, Dong-Hou

    2016-01-01

    Several lines of evidence have revealed that phosphorylation of amyloid precursor protein (APP) at Thr668 is involved in the pathogenesis of Alzheimer’s disease (AD). Okadaic acid (OA), a protein phosphatase-2A inhibitor, has been used in AD research models to increase tau phosphorylation and induce neuronal death. We previously showed that OA increased levels of APP and induced accumulation of APP in axonal swellings. In this study, we found that in OA-treated neurons, phosphorylation of APP at Thr668 increased and accumulated in axonal swellings by c-jun N-terminal kinase (JNK), and not by Cdk5 or ERK/MAPK. These results suggest that JNK may be one of therapeutic targets for the treatment of AD. [BMB Reports 2016; 49(7): 376-381] PMID:26839154

  3. Regulation of Nucleosome Stacking and Chromatin Compaction by the Histone H4 N-Terminal Tail-H2A Acidic Patch Interaction.

    PubMed

    Chen, Qinming; Yang, Renliang; Korolev, Nikolay; Liu, Chuan Fa; Nordenskiöld, Lars

    2017-03-16

    Chromatin folding and dynamics are critically dependent on nucleosome-nucleosome interactions with important contributions from internucleosome binding of the histone H4 N-terminal tail K16-R23 domain to the surface of the H2A/H2B dimer. The H4 Lys16 plays a pivotal role in this regard. Using in vitro reconstituted 12-mer nucleosome arrays, we have investigated the mechanism of the H4 N-terminal tail in maintaining nucleosome-nucleosome stacking and mediating intra- and inter-array chromatin compaction, with emphasis on the role of K16 and the positive charge region, R17-R23. Analytical ultracentrifugation sedimentation velocity experiments and precipitation assays were employed to analyze effects on chromatin folding and self-association, respectively. Effects on chromatin folding caused by various mutations and modifications at position K16 in the H4 histone were studied. Additionally, using charge-quenching mutations, we characterized the importance of the interaction of the residues within the H4 positive charge region R17-R23 with the H2A acidic patch of the adjacent nucleosome. Furthermore, crosslinking experiments were conducted to establish the proximity of the basic tail region to the acidic patch. Our data indicate that the positive charge and length of the side chain of H4 K16 are important for its access to the adjacent nucleosome in the process of nucleosome-nucleosome stacking and array folding. The location and orientation of the H4 R17-R23 domain on the H2A/H2B dimer surface of the neighboring nucleosome core particle (NCP) in the compacted chromatin fiber were established. The dominance of electrostatic interactions in maintaining intra-array interaction was demonstrated.

  4. Characterization of amino acid residues within the N-terminal region of Ubc9 that play a role in Ubc9 nuclear localization

    SciTech Connect

    Sekhri, Palak; Tao, Tao; Kaplan, Feige; Zhang, Xiang-Dong

    2015-02-27

    As the sole E2 enzyme for SUMOylation, Ubc9 is predominantly nuclear. However, the underlying mechanisms of Ubc9 nuclear localization are still not well understood. Here we show that RNAi-depletion of Imp13, an importin known to mediate Ubc9 nuclear import, reduces both Ubc9 nuclear accumulation and global SUMOylation. Furthermore, Ubc9-R13A or Ubc9-H20D mutation previously shown to interrupt the interaction of Ubc9 with nucleus-enriched SUMOs reduces the nuclear enrichment of Ubc9, suggesting that the interaction of Ubc9 with the nuclear SUMOs may enhance Ubc9 nuclear retention. Moreover, Ubc9-R17E mutation, which is known to disrupt the interaction of Ubc9 with both SUMOs and Imp13, causes a greater decrease in Ubc9 nuclear accumulation than Ubc9-R13A or Ubc9-H20D mutation. Lastly, Ubc9-K74A/S89D mutations that perturb the interaction of Ubc9 with nucleus-enriched SUMOylation-consensus motifs has no effect on Ubc9 nuclear localization. Altogether, our results have elucidated that the amino acid residues within the N-terminal region of Ubc9 play a pivotal role in regulation of Ubc9 nuclear localization. - Highlights: • Imp13-mediated nuclear import of Ubc9 is critical for global SUMOylation. • Ubc9 mutations disrupting Ubc9-SUMO interaction decrease Ubc9 nuclear accumulation. • N-terminal amino acid residues of Ubc9 are critical for Ubc9 nuclear enrichment.

  5. Direct influence of C-terminally substituted amino acids in the Dmt-Tic pharmacophore on delta-opioid receptor selectivity and antagonism.

    PubMed

    Balboni, Gianfranco; Salvadori, Severo; Guerrini, Remo; Negri, Lucia; Giannini, Elisa; Bryant, Sharon D; Jinsmaa, Yunden; Lazarus, Lawrence H

    2004-07-29

    A series of 17 analogues were developed on the basis of the general formula H-Dmt-Tic-NH-CH(R)-R' (denotes chirality; R = charged, neutral, or aromatic functional group; R' = -OH or -NH(2)). These compounds were designed to test the following hypothesis: the physicochemical properties of third-residue substitutions C-terminal to Tic in the Dmt-Tic pharmacophore modify delta-opioid receptor selectivity and delta-opioid receptor antagonism through enhanced interactions with the mu-opioid receptor. The data substantiate the following conclusions: (i) all compounds had high receptor affinity [K(i)(delta) = 0.034-1.1 nM], while that for the mu-opioid receptor fluctuated by orders of magnitude [K(i)(mu) = 15.1-3966 nM]; (ii) delta-opioid receptor selectivity [K(i)(mu)/K(i)(delta)] declined 1000-fold from 22,600 to 21; (iii) a C-terminal carboxyl group enhanced selectivity but only as a consequence of the specific residue; (iv) amidated, positive charged residues [Lys-NH(2) (6), Arg-NH(2) (7)], and a negatively charged aromatic residue [Trp-OH (11)] enhanced mu-opioid affinity [K(i)(mu) = 17.0, 15.1, and 15.7 nM, respectively], while Gly-NH(2) (8), Ser-NH(2) (10), and His-OH (12) were nearly one-tenth as active; and (v) D-isomers exhibited mixed effects on mu-opioid receptor affinity (2' < 3' < 4' < 1' < 5') and decreased delta-selectivity in D-Asp-NH(2) (1') and D-Lys(Ac)-OH (5'). The analogues exhibited delta-opioid receptor antagonism (pA(2) = 6.9-10.07) and weak mu-opioid receptor agonism (IC(50) > 1 microM) except H-Dmt-Tic-Glu-NH(2) (3), which was a partial delta-opioid receptor agonist (IC(50) = 2.5 nM). Thus, these C-terminally extended analogues indicated that an amino acid residue containing a single charge, amino or guanidino functionality, or aromatic group substantially altered the delta-opioid receptor activity profile (selectivity and antagonism) of the Dmt-Tic pharmacophore, which suggests that the C-terminal constituent plays a major role in determining

  6. Inflammatory responses and cell adhesion to self-assembled monolayers of alkanethiolates on gold.

    PubMed

    Barbosa, Judite N; Barbosa, Mário A; Aguas, Artur P

    2004-06-01

    The acute inflammatory response and the adhesion of cells to self-assembled monolayers (SAMs) of well-defined surface chemistry was studied in vivo using a rodent air-pouch model of inflammation. SAMs with three different terminal functional groups (OH, COOH and CH3) were implanted in subcutaneous air pouches induced in BALB/c mice. After 24 h, inflammatory cells were recovered from the air pouches and the implants were removed and prepared for observation by scanning electron microscopy (SEM). The implants coated with OH and CH3, were found to cause the highest recruitment of inflammatory cells into the subcutaneous pouches. Polymorphonuclear neutrophils (PMNs) leukocytes predominated over mononuclear cells in inflammatory exudates of SAMs-coated implants, the opposite being found in uncoated implants (controls). CH3-coated implants induced the highest number of inflammatory cells and also the largest percentage of PMNs seen in the subcutaneous pouches. Control and OH-covered implants presented the higher densities of attached inflammatory cells detected by SEM. In contrast, the CH3-coated implants showed a very low density of cells adherent to the implant surface. We conclude that the chemical nature and the degree of hydrophobicity of the surface of implants modulate both the local acute inflammatory reaction and the adhesion of leukocytes.

  7. Functional Role of N- and C-Terminal Amino Acids in the Structural Subunits of Colonization Factor CS6 Expressed by Enterotoxigenic Escherichia coli

    PubMed Central

    Debnath, Anusuya; Sabui, Subrata; Wajima, Takeaki; Hamabata, Takashi; Banerjee, Rajat

    2016-01-01

    ABSTRACT CS6 is a common colonization factor expressed by enterotoxigenic Escherichia coli. It is a two-subunit protein consisting of CssA and CssB in an equal stoichiometry, assembled via the chaperone-usher pathway into an afimbrial, oligomeric assembly on the bacterial cell surface. A recent structural study has predicted the involvement of the N- and C-terminal regions of the CS6 subunits in its assembly. Here, we identified the functionally important residues in the N- and C-terminal regions of the CssA and CssB subunits during CS6 assembly by alanine scanning mutagenesis. Bacteria expressing mutant proteins were tested for binding with Caco-2 cells, and the results were analyzed with respect to the surface expression of mutant CS6. In this assay, many mutant proteins were not expressed on the surface while some showed reduced expression. It appeared that some, but not all, of the residues in both the N and C termini of CssA and CssB played an important role in the intermolecular interactions between these two structural subunits, as well as chaperone protein CssC. Our results demonstrated that T20, K25, F27, S36, Y143, and V147 were important for the stability of CssA, probably through interaction of CssC. We also found that I22, V29, and I33 of CssA and G154, Y156, L160, V162, F164, and Y165 of CssB were responsible for CssA-CssB intermolecular interactions. In addition, some of the hydrophobic residues in the C terminus of CssA and the N terminus of CssB were involved in the stabilization of higher-order complex formation. Overall, the results presented here might help in understanding the pathway used to assemble CS6 and predict its structure. IMPORTANCE Unlike most other colonization factors, CS6 is nonfimbrial, and in a sense, its subunit composition and assembly are also unique. Here we report that both the N- and C-terminal amino acid residues of CssA and CssB play a critical role in the intermolecular interactions between them and assembly proteins

  8. A dielectric barrier discharge terminally inactivates RNase A by oxidizing sulfur-containing amino acids and breaking structural disulfide bonds

    NASA Astrophysics Data System (ADS)

    Lackmann, J.-W.; Baldus, S.; Steinborn, E.; Edengeiser, E.; Kogelheide, F.; Langklotz, S.; Schneider, S.; Leichert, L. I. O.; Benedikt, J.; Awakowicz, P.; Bandow, J. E.

    2015-12-01

    RNases are among the most stable proteins in nature. They even refold spontaneously after heat inactivation, regaining full activity. Due to their stability and universal presence, they often pose a problem when experimenting with RNA. We investigated the capabilities of nonthermal atmospheric-pressure plasmas to inactivate RNase A and studied the inactivation mechanism on a molecular level. While prolonged heating above 90 °C is required for heat inactivating RNase A, direct plasma treatment with a dielectric barrier discharge (DBD) source caused permanent inactivation within minutes. Circular dichroism spectroscopy showed that DBD-treated RNase A unfolds rapidly. Raman spectroscopy indicated methionine modifications and formation of sulfonic acid. A mass spectrometry-based analysis of the protein modifications that occur during plasma treatment over time revealed that methionine sulfoxide formation coincides with protein inactivation. Chemical reduction of methionine sulfoxides partially restored RNase A activity confirming that sulfoxidation is causal and sufficient for RNase A inactivation. Continued plasma exposure led to over-oxidation of structural disulfide bonds. Using antibodies, disulfide bond over-oxidation was shown to be a general protein inactivation mechanism of the DBD. The antibody’s heavy and light chains linked by disulfide bonds dissociated after plasma exposure. Based on their ability to inactivate proteins by oxidation of sulfur-containing amino acids and over-oxidation of disulfide bonds, DBD devices present a viable option for inactivating undesired or hazardous proteins on heat or solvent-sensitive surfaces.

  9. The cytoskeletal protein alpha-actinin regulates acid-sensing ion channel 1a through a C-terminal interaction.

    PubMed

    Schnizler, Mikael K; Schnizler, Katrin; Zha, Xiang-Ming; Hall, Duane D; Wemmie, John A; Hell, Johannes W; Welsh, Michael J

    2009-01-30

    The acid-sensing ion channel 1a (ASIC1a) is widely expressed in central and peripheral neurons where it generates transient cation currents when extracellular pH falls. ASIC1a confers pH-dependent modulation on postsynaptic dendritic spines and has critical effects in neurological diseases associated with a reduced pH. However, knowledge of the proteins that interact with ASIC1a and influence its function is limited. Here, we show that alpha-actinin, which links membrane proteins to the actin cytoskeleton, associates with ASIC1a in brain and in cultured cells. The interaction depended on an alpha-actinin-binding site in the ASIC1a C terminus that was specific for ASIC1a versus other ASICs and for alpha-actinin-1 and -4. Co-expressing alpha-actinin-4 altered ASIC1a current density, pH sensitivity, desensitization rate, and recovery from desensitization. Moreover, reducing alpha-actinin expression altered acid-activated currents in hippocampal neurons. These findings suggest that alpha-actinins may link ASIC1a to a macromolecular complex in the postsynaptic membrane where it regulates ASIC1a activity.

  10. Specific accumulation of GFP in a non-acidic vacuolar compartment via a C-terminal propeptide-mediated sorting pathway.

    PubMed

    Di Sansebastiano, G P; Paris, N; Marc-Martin, S; Neuhaus, J M

    1998-08-01

    The green fluorescent protein (GFP) from Aequorea victoria can be detected in living plant cells after transient transformation of protoplasts. Expression of the GFP can be used to monitor protein trafficking in a mixed cell population and also to study the different function and importance of organelles in different cell types. We developed a vacuolar form of GFP that was obtained by replacing the C-terminal endoplasmic reticulum (ER)-retention motif of mGFP5-ER by the vacuolar targeting peptide of tobacco chitinase A. The vacuolar GFP was transported and accumulated in the vacuole as expected. However, we found two patterns of GFP accumulation after prolonged incubation (18-24 h) depending on the cell type. Most chloroplast-rich protoplasts had a fluorescent large central vacuole. In contrast, most chloroplast-poor protoplasts accumulated the GFP in one smaller vacuole but not in the large central vacuole, which was visible under a light microscope in the same cell. This differential accumulation reflected the existence of two different vacuolar compartments as described recently by immunolocalization of several vacuolar markers. We were able to characterize the vacuolar compartment to which GFP is specifically targeted as non-acidic, since it did not accumulate neutral red while acidic vacuoles did not accumulate GFP.

  11. Independent repression of bile acid synthesis and activation of c-Jun N-terminal kinase (JNK) by activated hepatocyte fibroblast growth factor receptor 4 (FGFR4) and bile acids.

    PubMed

    Yu, Chundong; Wang, Fen; Jin, Chengliu; Huang, Xinqiang; McKeehan, Wallace L

    2005-05-06

    The fibroblast growth factor (FGF) receptor complex is a regulator of adult organ homeostasis in addition to its central role in embryonic development and wound healing. FGF receptor 4 (FGFR4) is the sole FGFR receptor kinase that is significantly expressed in mature hepatocytes. Previously, we showed that mice lacking mouse FGFR4 (mR4(-/-)) exhibited elevated fecal bile acids, bile acid pool size, and expression of liver cholesterol 7alpha-hydroxylase (CYP7A1), the rate-limiting enzyme for canonical neutral bile acid synthesis. To prove that hepatocyte FGFR4 was a negative regulator of cholesterol metabolism and bile acid synthesis independent of background, we generated transgenic mice overexpressing a constitutively active human FGFR4 (CahR4) in hepatocytes and crossed them with the FGFR4-deficient mice to generate CahR4/mR4(-/-) mice. In mice expressing active FGFR4 in liver, fecal bile acid excretion was 64%, bile acid pool size was 47%, and Cyp7a1 expression was 10-30% of wild-type mice. The repressed level of Cyp7a1 expression was resistant to induction by a high cholesterol diet relative to wild-type mice. Expression of CahR4 in mR4(-/-) mouse livers depressed bile acid synthesis below wild-type levels from the elevated levels observed in mR4(-/-). Levels of phosphorylated c-Jun N-terminal kinase (JNK), which is part of a pathway implicated in bile acid-mediated repression of synthesis, was 30% of wild-type levels in mR4(-/-) livers, whereas CahR4 livers exhibited an average 2-fold increase. However, cholate still strongly induced phospho-JNK in mR4(-/-) livers. These results confirm that hepatocyte FGFR4 regulates bile acid synthesis by repression of Cyp7a1 expression. Hepatocyte FGFR4 may contribute to the repression of bile acid synthesis through JNK signaling but is not required for activation of JNK signaling by bile acids.

  12. Accelerating the clinical development of protein-based vaccines for malaria by efficient purification using a four amino acid C-terminal 'C-tag'.

    PubMed

    Jin, Jing; Hjerrild, Kathryn A; Silk, Sarah E; Brown, Rebecca E; Labbé, Geneviève M; Marshall, Jennifer M; Wright, Katherine E; Bezemer, Sandra; Clemmensen, Stine B; Biswas, Sumi; Li, Yuanyuan; El-Turabi, Aadil; Douglas, Alexander D; Hermans, Pim; Detmers, Frank J; de Jongh, Willem A; Higgins, Matthew K; Ashfield, Rebecca; Draper, Simon J

    2017-01-30

    Development of bespoke biomanufacturing processes remains a critical bottleneck for translational studies, in particular when modest quantities of a novel product are required for proof-of-concept Phase I/II clinical trials. In these instances the ability to develop a biomanufacturing process quickly and relatively cheaply, without risk to product quality or safety, provides a great advantage by allowing new antigens or concepts in immunogen design to more rapidly enter human testing. These challenges with production and purification are particularly apparent when developing recombinant protein-based vaccines for difficult parasitic diseases, with Plasmodium falciparum malaria being a prime example. To that end, we have previously reported the expression of a novel protein vaccine for malaria using the ExpreS(2)Drosophila melanogaster Schneider 2 stable cell line system, however, a very low overall process yield (typically <5% recovery of hexa-histidine-tagged protein) meant the initial purification strategy was not suitable for scale-up and clinical biomanufacture of such a vaccine. Here we describe a newly available affinity purification method that was ideally suited to purification of the same protein which encodes the P. falciparum reticulocyte-binding protein homolog 5 - currently the leading antigen for assessment in next generation vaccines aiming to prevent red blood cell invasion by the blood-stage parasite. This purification system makes use of a C-terminal tag known as 'C-tag', composed of the four amino acids, glutamic acid - proline - glutamic acid - alanine (E-P-E-A), which is selectively purified on a CaptureSelect™ affinity resin coupled to a camelid single chain antibody, called NbSyn2. The C-terminal fusion of this short C-tag to P. falciparum reticulocyte-binding protein homolog 5 achieved >85% recovery and >70% purity in a single step purification directly from clarified, concentrated Schneider 2 cell supernatant under mild conditions

  13. The Prebiotic C-Terminal Elongation of Peptides can be Initiated by N-Carbamoyl Amino Acids.

    PubMed

    Abou Mrad, Ninette; Ajram, Ghinwa; Rossi, Jean-Christophe; Boiteau, Laurent; Duvernay, Fabrice; Pascal, Robert; Danger, Gregoire

    2017-04-05

    The formation of peptides upon EDC promoted activation of N-carbamoylamino acids (CAA), was considered in the scope of our recent works on carbodiimide promoted C-terminus elongation of peptides in a prebiotic context. Thus EDC promoted activation of CAA derivatives of Tyr(Me) or Ala in dilute aqueous medium pH 5.5-6.5 in the presence of excess of AA, resulted in peptide formation via C-terminus activation / elongation. Kinetic results similar to those of EDC-mediated activation of N-acyl-AA lead us to postulate the formation of a 2-amino-5(4H)-oxazolone intermediate by cyclization of the activated CAA, in spite of the absence of epimerization occurred at CAA residues. Thus, in a prebiotic context, CAA may have played a similar role as N-acyl-AA in the initiation of C-terminus peptide elongation.

  14. Investigating the Physical Basis of Amorphous Precursor Transformation to Calcite Using Patterned Alkanethiol Surfaces

    NASA Astrophysics Data System (ADS)

    Wang, D.; Wallace, A.; Han, T. Y.; Lee, J. R.; Hailey, P. D.; de Yoreo, J. J.; Dove, P. M.

    2007-12-01

    Increasing evidence from X-ray Absorption Spectroscopy and Environmental Scanning Electron Microscopy (ESEM) studies of biominerals extracted from calcifying organisms show that amorphous calcium carbonate (ACC) plays a key role in the initial formation of carbonate minerals and in shaping them into complex morphologies. Echinoderms and possibly a wide variety of other organisms, use ACC as a precursor phase. The ACC is first formed within spatial and temporally controlled environments such as vesicles, followed by a subsequent onset of mineralization that transforms the precursor into a fully crystalline material. Recent studies on sea urchin embryos have shown that during this transformation, ACC develops short-range order that resembles calcite before fully crystallizing. While this "non-traditional" process is recognized, the mechanisms and factors that govern this transformation remain poorly understood. Of particular interest are the roles of water, and the functional group chemistry of surfaces and macromolecules within mineralization environments. To investigate these questions, we have developed an experimental approach using ESEM that allows us to control impurity concentration, surface functionality and water content through the degree of water condensation. Patterned self-assembled monolayers (SAM) of hydrophilic moieties with domains of approximately 25 microns in diameter are used to form an array of micro-reactors. ACC particles with known composition are then deposited on the patterns. Condensing water in the ESEM initializes the transformation of ACC to calcite. Our results show that in saturated water vapor, ACC swells, but no obvious faceting of the material occurs. It is only in bulk water, via dissolution/crystallization, where the calcite grown on carboxyl-terminated surfaces is found with the often-observed \\{013\\} nucleation face. We use this insight to understand the role of the different chemical moieties on ACC to calcite transformation

  15. Precursor Ion–Ion Aggregation in the Brust–Schiffrin Synthesis of Alkanethiol Nanoparticles

    SciTech Connect

    Graham, Trent R.; Renslow, Ryan; Govind, Niranjan; Saunders, Steven R.

    2016-09-08

    Tetraoctylammonium bromide is used in the Brust-Schiffrin nanoparticle synthesis to phase-transfer chloroaurate ions from the aqueous phase to the organic phase. While it is established that the quaternary ammonium complex self-associates in the organic phase, the actual self-assembled structure is debated. We have confirmed the presence of ion-ion aggregates through quantitative 1H Nuclear Magnetic Resonance spectroscopy (NMR), pulsed field gradient, diffusion-ordered NMR (DOSY-NMR) and density functional theory (DFT) based NMR shift calculations. Tetraoctylammonium complexes (TOA-X, where X = Br, Cl, AuCl4-xBrx, AuBr4/Br and AuCl4-xBrx/Br) were investigated to measure the extraction of water into the organic phase. 1H NMR and DFT based NMR shielding calculations indicated that deshielding of water is due to hydration of the anion and not the formation of the aqueous core of a reverse micelle. DOSYNMR results were consistent with the formation of small aggregates at typical Brust-Schiffrin synthesis concentrations. The extent of aggregation correlated with the size and electronegativity of the anion and was analyzed with a modified, isodesmic, indefinite aggregation model. The substitution of bromoauric acid for chlororoauric acid at conditions emulating the Brust-Schiffrin synthesis increased the aggregation of the quaternary ammonium complex. The increase in aggregation corresponded with an increase in the size of the produced nanoparticles from 4.3 to 4.6 nm. Understanding the selfassembly and supramolecular structure of precursors in the Brust-Schiffrin synthesis will enable further refinement of models that predict the growth of noble metal nanoparticles.

  16. Bank Terminals

    NASA Technical Reports Server (NTRS)

    1978-01-01

    In the photo, employees of the UAB Bank, Knoxville, Tennessee, are using Teller Transaction Terminals manufactured by SCI Systems, Inc., Huntsville, Alabama, an electronics firm which has worked on a number of space projects under contract with NASA. The terminals are part of an advanced, computerized financial transaction system that offers high efficiency in bank operations. The key to the system's efficiency is a "multiplexing" technique developed for NASA's Space Shuttle. Multiplexing is simultaneous transmission of large amounts of data over a single transmission link at very high rates of speed. In the banking application, a small multiplex "data bus" interconnects all the terminals and a central computer which stores information on clients' accounts. The data bus replaces the maze-of wiring that would be needed to connect each terminal separately and it affords greater speed in recording transactions. The SCI system offers banks real-time data management through constant updating of the central computer. For example, a check is immediately cancelled at the teller's terminal and the computer is simultaneously advised of the transaction; under other methods, the check would be cancelled and the transaction recorded at the close of business. Teller checkout at the end of the day, conventionally a time-consuming matter of processing paper, can be accomplished in minutes by calling up a summary of the day's transactions. SCI manufactures other types of terminals for use in the system, such as an administrative terminal that provides an immediate printout of a client's account, and another for printing and recording savings account deposits and withdrawals. SCI systems have been installed in several banks in Tennessee, Arizona, and Oregon and additional installations are scheduled this year.

  17. Homology of the NH2-terminal amino acid sequences of the heavy and light chains of human monoclonal lupus autoantibodies containing the dominant 16/6 idiotype.

    PubMed Central

    Atkinson, P M; Lampman, G W; Furie, B C; Naparstek, Y; Schwartz, R S; Stollar, B D; Furie, B

    1985-01-01

    The NH2-terminal amino acid sequences have been determined by automated Edman degradation for the heavy and light chains of five monoclonal IgM anti-DNA autoantibodies that were produced by human-human hybridomas derived from lymphocytes of two patients with systemic lupus erythematosus. Four of the antibodies were closely related to the idiotype system 16/6, whereas the fifth antibody was unrelated idiotypically. The light chains of the 16/6 idiotype-positive autoantibodies (HF2-1/13b, HF2-1/17, HF2-18/2, and HF3-16/6) had identical amino acid sequences from residues 1 to 40. Their framework structures were characteristic of VKI light chains. The light chain of the 16/6 idiotype-negative autoantibody HF6-21/28 was characteristic of the VKII subgroup. The heavy chains of the 16/6 idiotype-positive autoantibodies had nearly identical amino acid sequences from residues 1 to 40. The framework structures were characteristic of the VHIII subgroup. In contrast, the GM4672 fusion partner of the hybridoma produced small quantities of an IgG with a VHI heavy chain and a VKI light chain. The heavy chains of the lupus autoantibodies and the light chains of those autoantibodies that were idiotypically related to the 16/6 system had marked sequence homology with WEA, a Waldenstrom IgM that binds to Klebsiella polysaccharides and expresses the 16/6 idiotype. These results indicate a striking homology in the amino termini of the heavy and light chains of the lupus autoantibodies studied and suggest that the V regions of the heavy and light chains of the 16/6 idiotype-positive DNA-binding lupus auto-antibodies are each encoded by a single germ line gene. PMID:3921567

  18. Passive immunization targeting the N-terminal region of phosphorylated tau (residues 68-71) improves spatial memory in okadaic acid induced tauopathy model rats.

    PubMed

    Subramanian, Sarada; Savanur, Ganesh; Madhavadas, Sowmya

    2017-01-29

    Alzheimer's disease (AD) is the leading cause of dementia, characterized by progressive loss of memory and other cognitive functions. The cognitive impairment in patients with AD is closely associated with loss of synapses and the formation of neurofibrillary tangles (NFT) containing hyperphosphorylated tau in the hippocampus. Effective treatment for AD is still not available. In this study, the sequence comprising of residues 50-71 in the N-terminal region of tau, containing theoretically predicted B- and T-cell epitopes in close proximity to pathologically relevant phospho-serine (residue 68) and phospho-threonine (residues 69, 71) was selected as a potential immunotherapeutic peptide. This 22-residue long phospho-peptide ((50)TPTEDGSEEPGSETSDAKpSpTPpT(71)) was custom synthesized and its therapeutic potential was tested in experimental rats. For this purpose, adult Sprague-Dawley rats were intranasally treated with okadaic acid (OA), a selective inhibitor of protein phosphatase PP2A. Within a day of OA administration, these rats showed marked impairment in cognitive functions with a significant increase in p-tau/t-tau ratio in the hippocampal homogenates. Passive immunization studies conducted in these OA treated rats with polyclonal anti-phospho-peptide antibodies resulted in a significant improvement in learning and memory functions in Barne's maze task. Further, p-tau levels in the hippocampal homogenates were reduced. In addition, these antibodies effectively prevented the aggregation of recombinant tau in vitro. These results demonstrate that targeting N-terminal region of tau harbouring the phospho-residue cluster 68-71 would be beneficial and may present an effective therapeutic opportunity for AD and other tauopathies.

  19. A core of three amino acids at the carboxyl-terminal region of glutamine synthetase defines its regulation in cyanobacteria.

    PubMed

    Saelices, Lorena; Robles-Rengel, Rocío; Florencio, Francisco J; Muro-Pastor, M Isabel

    2015-05-01

    Glutamine synthetase (GS) type I is a key enzyme in nitrogen metabolism, and its activity is finely controlled by cellular carbon/nitrogen balance. In cyanobacteria, a reversible process that involves protein-protein interaction with two proteins, the inactivating factors IF7 and IF17, regulates GS. Previously, we showed that three arginine residues of IFs are critical for binding and inhibition of GS. In this work, taking advantage of the specificity of GS/IFs interaction in the model cyanobacteria Synechocystis sp. PCC 6803 and Anabaena sp. PCC 7120, we have constructed a different chimeric GSs from these two cyanobacteria. Analysis of these proteins, together with a site-directed mutagenesis approach, indicates that a core of three residues (E419, N456 and R459) is essential for the inactivation process. The three residues belong to the last 56 amino acids of the C-terminus of Synechocystis GS. A protein-protein docking modeling of Synechocystis GS in complex with IF7 supports the role of the identified core for GS/IF interaction.

  20. Antimicrobial activity of pleurocidin is retained in Plc-2, a C-terminal 12-amino acid fragment.

    PubMed

    Souza, Andre L A; Díaz-Dellavalle, Paola; Cabrera, Andrea; Larrañaga, Patricia; Dalla-Rizza, Marco; De-Simone, Salvatore G

    2013-07-01

    An analysis of a series of five peptides composed of various portions of the pleurocidin (Plc) sequence identified a l2-amino acid fragment from the C-terminus of Plc, designated Plc-2, as the smallest fragment that retained a antimicrobial activity comparable to that of the parent compound. MIC tests in vitro with low-ionic-strength medium showed that Plc-2 has potent activity against Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus but not against Enterococcus faecalis. The antifungal activity of the synthetic peptides against phytopathogenic fungi, such as Fusarium oxysporum, Colletotrichum sp., Aspergillus niger and Alternaria sp., also identified Plc-2 as a biologically active peptide. Microscopy studies of fluorescently stained fungi treated with Plc-2 demonstrated that cytoplasmic and nuclear membranes were compromised in all strains of phytopathogenic fungi tested. Together, these results identify Plc-2 as a potential antimicrobial agent with similar properties to its parent compound, pleurocidin. In addition, it demonstrated that the KHVGKAALTHYL residues are critical for the antimicrobial activity described for pleurocidin.

  1. Mechanism of fusidic acid inhibition of RRF- and EF-G-dependent splitting of the bacterial post-termination ribosome

    PubMed Central

    Borg, Anneli; Pavlov, Michael; Ehrenberg, Måns

    2016-01-01

    The antibiotic drug fusidic acid (FA) is commonly used in the clinic against gram-positive bacterial infections. FA targets ribosome-bound elongation factor G (EF-G), a translational GTPase that accelerates both messenger RNA (mRNA) translocation and ribosome recycling. How FA inhibits translocation was recently clarified, but FA inhibition of ribosome recycling by EF-G and ribosome recycling factor (RRF) has remained obscure. Here we use fast kinetics techniques to estimate mean times of ribosome splitting and the stoichiometry of GTP hydrolysis by EF-G at varying concentrations of FA, EF-G and RRF. These mean times together with previous data on uninhibited ribosome recycling were used to clarify the mechanism of FA inhibition of ribosome splitting. The biochemical data on FA inhibition of translocation and recycling were used to model the growth inhibitory effect of FA on bacterial populations. We conclude that FA inhibition of translocation provides the dominant cause of bacterial growth reduction, but that FA inhibition of ribosome recycling may contribute significantly to FA-induced expression of short regulatory open reading frames, like those involved in FA resistance. PMID:27001509

  2. Mechanism of fusidic acid inhibition of RRF- and EF-G-dependent splitting of the bacterial post-termination ribosome.

    PubMed

    Borg, Anneli; Pavlov, Michael; Ehrenberg, Måns

    2016-04-20

    The antibiotic drug fusidic acid (FA) is commonly used in the clinic against gram-positive bacterial infections. FA targets ribosome-bound elongation factor G (EF-G), a translational GTPase that accelerates both messenger RNA (mRNA) translocation and ribosome recycling. How FA inhibits translocation was recently clarified, but FA inhibition of ribosome recycling by EF-G and ribosome recycling factor (RRF) has remained obscure. Here we use fast kinetics techniques to estimate mean times of ribosome splitting and the stoichiometry of GTP hydrolysis by EF-G at varying concentrations of FA, EF-G and RRF. These mean times together with previous data on uninhibited ribosome recycling were used to clarify the mechanism of FA inhibition of ribosome splitting. The biochemical data on FA inhibition of translocation and recycling were used to model the growth inhibitory effect of FA on bacterial populations. We conclude that FA inhibition of translocation provides the dominant cause of bacterial growth reduction, but that FA inhibition of ribosome recycling may contribute significantly to FA-induced expression of short regulatory open reading frames, like those involved in FA resistance.

  3. Deletion of N-terminal amino acids from human lecithin:cholesterol acyltransferase differentially affects enzyme activity toward alpha- and beta-substrate lipoproteins.

    PubMed

    Vickaryous, Nicola K; Teh, Evelyn M; Stewart, Bruce; Dolphin, Peter J; Too, Catherine K L; McLeod, Roger S

    2003-03-21

    Lecithin:cholesterol acyltransferase (LCAT) is the enzyme responsible for generation of the majority of the cholesteryl esters (CE) in human plasma. Although most plasma cholesterol esterification occurs on high-density lipoprotein (HDL), via alpha-LCAT activity, esterification also occurs on low-density lipoprotein (LDL) via the beta-activity of the enzyme. Computer threading techniques have provided a three-dimensional model for use in the structure-function analysis of the core and catalytic site of the LCAT protein, but the model does not extend to the N-terminal region of the enzyme, which may mediate LCAT interaction with lipoprotein substrates. In the present study, we have examined the functional consequences of deletion of the highly conserved hydrophobic N-terminal amino acids (residues 1-5) of human LCAT. Western blot analysis showed that the mutant proteins (Delta 1-Delta 5) were synthesized and secreted from transfected COS-7 cells at levels approximately equivalent to those of wild-type hLCAT. The secreted proteins had apparent molecular weights of 67 kDa, indicating that they were correctly processed and glycosylated during cellular transit. However, deletion of the first residue of the mature LCAT protein (Delta 1 mutant) resulted in a dramatic loss of alpha-LCAT activity (5% of wild type using reconstituted HDL substrate, rHDL), although this mutant retained full beta-LCAT activity (108% of wild-type using human LDL substrate). Removal of residues 1 and 2 (Delta 2 mutant) abolished alpha-LCAT activity and reduced beta-LCAT activity to 12% of wild type. Nevertheless, LCAT Delta 1 and Delta 2 mutants retained their ability to bind to rHDL and LDL lipoprotein substrates. The dramatic loss of enzyme activity suggests that the N-terminal residues of LCAT may be involved in maintaining the conformation of the lid domain and influence activation by the alpha-LCAT cofactor apoA-I (in Delta 1) and/or loss of enzyme activity (in Delta 1-Delta 5). Since the

  4. Effects of two novel amino acid substitutions on the penicillin binding properties of the PBP5 C‑terminal from Enterococcus faecium.

    PubMed

    Zhou, Chengjiang; Niu, Haiying; Yu, Hui; Zhou, Lishe; Wang, Zhanli

    2015-10-01

    The low‑affinity penicillin‑binding protein (PBP)5 is responsible for resistance to β‑lactam antibiotics in Enterococcus faecium. (E. faecium). In order to evaluate more fully the potential of this species for the development of resistance to β-lactam antibiotics, the present study aimed to examine the extent of penicillin-binding protein (PBP) variations in a collection of clinical E. faecium isolates. In the present study, the C‑terminal domain of PBP5 (PBP5‑CD) of 13 penicillin‑resistant clinical isolates of E. faecium were sequenced and the correlation between penicillin resistance and particular amino acid changes were analyzed. The present study identified for the first time, to the best of our knowledge, two novel substitutions (Tyr460Phe and Ala462Thr or Val462Thr) of E. faecium PBP5‑CD. The covalent interaction between penicillin and PBP5‑CD was also investigated using homology modeling and molecular docking methods. The theoretical calculation revealed that Phe460 and Thr462 were involved in penicillin binding, suggesting that substitutions at these positions exert effects on the affinity for penicillin, and this increased affinity translates into lower resistance in vitro.

  5. CDDP supramolecular micelles fabricated from adamantine terminated mPEG and β-cyclodextrin based seven-armed poly (L-glutamic acid)/CDDP complexes.

    PubMed

    Yong, Dawei; Luo, Yu; Du, Fang; Huang, Jin; Lu, Wei; Dai, Zhaoyun; Yu, Jiahui; Liu, Shiyuan

    2013-05-01

    This research is aimed to develop a nano-sized supramolecular micelle delivery system of cis-dichlorodiammine platinum (II) (CDDP) in order to achieve the passive tumor targeting. Firstly, star-shaped poly (γ-benzyl-L-glutamate) was synthesized by the ring-opening polymerization of γ-benzyl-L-glutamate-N-carboxyanhydride initiated with per-6-amino-β-cyclodextrin. After removal of benzyl groups, β-cyclodextrin based seven-armed poly (L-glutamic acid) (β-CD-7PLGA) was obtained. β-CD-7PLGA/CDDP complexes were prepared by the complex reaction between the carboxylic groups of β-CD-7PLGA and CDDP. Further inclusion of β-CD-7PLGA/CDDP complexes with adamantine terminated mPEG (mPEG-Ad) gave CDDP supramolecular micelles (mPEG-Ad@β-CD-7PLGA/CDDP). The formation of mPEG-Ad@β-CD-7PLGA/CDDP supramolecular micelles was confirmed by fluorescence spectrophotoscopy and particle size measurements. All the micelles showed spherical shape, and their sizes increased from 100 to 135 nm with the increase of PLGA arm molecular weight. mPEG-Ad@CD-7PLGA/CDDP micelles showed sustained drug release profiles over 50h in PBS. Compared with CDDP, mPEG-Ad@β-CD-7PLGA/CDDP supramolecular micelles showed essential decreased cytotoxicity to KB cells, suggesting their great potential as the delivery carriers of CDDP.

  6. c-Jun Amino-Terminal Kinase is Involved in Valproic Acid-Mediated Neuronal Differentiation of Mouse Embryonic NSCs and Neurite Outgrowth of NSC-Derived Neurons.

    PubMed

    Lu, Lu; Zhou, Hengxing; Pan, Bin; Li, Xueying; Fu, Zheng; Liu, Jun; Shi, Zhongju; Chu, Tianci; Wei, Zhijian; Ning, Guangzhi; Feng, Shiqing

    2017-04-01

    Valproic acid (VPA), an anticonvulsant and mood-stabilizing drug, can induce neuronal differentiation, promote neurite extension and exert a neuroprotective effect in central nervous system (CNS) injuries; however, comparatively little is known regarding its action on mouse embryonic neural stem cells (NSCs) and the underlying molecular mechanism. Recent studies suggested that c-Jun N-terminal kinase (JNK) is required for neurite outgrowth and neuronal differentiation during neuronal development. In the present study, we cultured mouse embryonic NSCs and treated the cells with 1 mM VPA for up to 7 days. The results indicate that VPA promotes the neuronal differentiation of mouse embryonic NSCs and neurite outgrowth of NSC-derived neurons; moreover, VPA induces the phosphorylation of c-Jun by JNK. In contrast, the specific JNK inhibitor SP600125 decreased the VPA-stimulated increase in neuronal differentiation of mouse embryonic NSCs and neurite outgrowth of NSC-derived neurons. Taken together, these results suggest that VPA promotes neuronal differentiation of mouse embryonic NSCs and neurite outgrowth of NSC-derived neurons. Moreover, JNK activation is involved in the effects of VPA stimulation.

  7. Serum Concentrations of Ubiquitin C-Terminal Hydrolase-L1 and Glial Fibrillary Acidic Protein after Pediatric Traumatic Brain Injury

    PubMed Central

    Mondello, Stefania; Kobeissy, Firas; Vestri, Annarita; Hayes, Ronald L.; Kochanek, Patrick M.; Berger, Rachel P.

    2016-01-01

    Objective reliable markers to assess traumatic brain injury (TBI) and predict outcome soon after injury are a highly needed tool for optimizing management of pediatric TBI. We assessed serum concentrations of Glial Fibrillary Acidic Protein (GFAP) and Ubiquitin C-Terminal Hydrolase-L1 (UCH-L1) in a cohort of 45 children with clinical diagnosis of TBI (Glasgow Coma Scale [GCS] 3–15) and 40 healthy subjects, evaluated their associations with clinical characteristics and outcomes, and compared their performance to previously published data on two well-studied blood biomarkers, S100B and MBP. We observed higher serum levels of GFAP and UCH-L1 in brain-injured children compared with controls and also demonstrated a step-wise increase of biomarker concentrations over the continuum of severity from mild to severe TBI. Furthermore, while we found that only the neuronal biomarker UCH-L1 holds potential to detect acute intracranial lesions as assessed by computed tomography (CT), both markers were substantially increased in TBI patients even with a normal CT suggesting the presence of undetected microstructural injuries. Serum UCH-L1 and GFAP concentrations also strongly predicted poor outcome and performed better than S100B and MBP. Our results point to a role of GFAP and UCH-L1 as candidate biomarkers for pediatric TBI. Further studies are warranted. PMID:27319802

  8. Influenza A virus virulence depends on two amino acids in the N-terminal domain of its NS1 protein facilitating inhibition of PKR.

    PubMed

    Schierhorn, Kristina L; Jolmes, Fabian; Bespalowa, Julia; Saenger, Sandra; Peteranderl, Christin; Dzieciolowski, Julia; Budt, Matthias; Pleschka, Stephan; Herrmann, Andreas; Herold, Susanne; Wolff, Thorsten

    2017-03-01

    main activity of the amino acids 35 and 46 as the strong attenuation of corresponding mutant viruses in human cells was rescued to a large extent by lowering PKR expression levels. Significantly, this corresponded with restoration of viral virulence for NS1 R35A and R46A mutant viruses in PKR(-/-) mice. Therefore, our data establish a model in which the NS1 N-terminal domain engages in a binding interaction to inhibit activation of PKR and ensure efficient viral propagation and virulence.

  9. Terminal structure

    DOEpatents

    Schmidt, Frank; Allais, Arnaud; Mirebeau, Pierre; Ganhungu, Francois; Lallouet, Nicolas

    2009-10-20

    A terminal structure (2) for a superconducting cable (1) is described. It consists of a conductor (2a) and an insulator (2b) that surrounds the conductor (2a), wherein the superconducting cable (1) has a core with a superconducting conductor (5) and a layer of insulation that surrounds the conductor (5), and wherein the core is arranged in such a way that it can move longitudinally in a cryostat. The conductor (2a) of the terminal structure (2) is electrically connected with the superconducting conductor (5) or with a normal conductor (6) that is connected with the superconducting conductor (5) by means of a tubular part (7) made of an electrically conductive material, wherein the superconducting conductor (5) or the normal conductor (6) can slide in the part (7) in the direction of the superconductor.

  10. Terminal Ballistics

    DTIC Science & Technology

    1976-02-01

    ballistics doe, little to c~plaini the workings of explosike pro jectiles. The termni,iaf phase (of di esplodling tbalfftic weapon is comiposed of esents...citterior, and terminal baillistic phases, and the study of this n’!w systemn hius useful parallel% it) the proiecoile ballistic sysStem. The...charge liner collapse Vi Jet velocity V, Slug velocity W Work Wp Weight of projecti!e Z A length variable a, bi Empirical constants. (In Chap. 5, Eq

  11. Investigation of the mechanism of electroless deposition of copper on functionalized alkanethiolate self-assembled monolayers adsorbed on gold.

    PubMed

    Lu, Peng; Walker, Amy V

    2007-12-04

    We have investigated the reaction pathways involved in the unseeded electroless deposition of copper on self-assembled monolayers (SAMs) adsorbed on Au, using time-of-flight secondary ion mass spectrometry, optical microscopy, and scanning electron microscopy. At 22 degrees C copper deposits on both -CH3 and -COOH terminated SAMs. No copper deposition is observed on -OH terminated SAMs because the hydroxyl terminal groups react with formaldehyde in the plating solution, forming an acetal which prevents Cu deposition. At higher deposition temperatures (45 degrees C), no Cu is observed to deposit on -CH3 terminated SAMs because Cu2+ ions are not stabilized on the SAM surface. Copper complexes are still able to form with the -COOH terminal group at 45 degrees C, and so copper continues to be deposited on -COOH terminated SAMs. Copper also penetrates through -CH3 and -COOH terminated SAMs to the Au/S interface, suggesting that soft deposition techniques do not prevent the penetration of low-to-moderate reactivity metals through organic films.

  12. Termination unit

    DOEpatents

    Traeholt, Chresten; Willen, Dag; Roden, Mark; Tolbert, Jerry C.; Lindsay, David; Fisher, Paul W.; Nielsen, Carsten Thidemann

    2016-05-03

    Cable end section comprises end-parts of N electrical phases/neutral, and a thermally-insulation envelope comprising cooling fluid. The end-parts each comprises a conductor and are arranged with phase 1 innermost, N outermost surrounded by the neutral, electrical insulation being between phases and N and neutral. The end-parts comprise contacting surfaces located sequentially along the longitudinal extension of the end-section. A termination unit has an insulating envelope connected to a cryostat, special parts at both ends comprising an adapter piece at the cable interface and a closing end-piece terminating the envelope in the end-section. The special parts houses an inlet and/or outlet for cooling fluid. The space between an inner wall of the envelope and a central opening of the cable is filled with cooling fluid. The special part at the end connecting to the cryostat houses an inlet or outlet, splitting cooling flow into cable annular flow and termination annular flow.

  13. Protection efficacy of the Brucella abortus ghost vaccine candidate lysed by the N-terminal 24-amino acid fragment (GI24) of the 36-amino acid peptide PMAP-36 (porcine myeloid antimicrobial peptide 36) in murine models

    PubMed Central

    KWON, Ae Jeong; MOON, Ja Young; KIM, Won Kyong; KIM, Suk; HUR, Jin

    2016-01-01

    Brucella abortus cells were lysed by the N-terminal 24-amino acid fragment (GI24) of the 36-amino acid peptide PMAP-36 (porcine myeloid antimicrobial peptide 36). Next, the protection efficacy of the lysed fragment as a vaccine candidate was evaluated. Group A mice were immunized with sterile PBS, group B mice were intraperitoneally (ip) immunized with 3 × 108 colony-forming units (CFUs) of B. abortus strain RB51, group C mice were immunized ip with 3 × 108 cells of the B. abortus vaccine candidate, and group D mice were orally immunized with 3 × 109 cells of the B. abortus vaccine candidate. Brucella lipopolysaccharide (LPS)-specific serum IgG titers were considerably higher in groups C and D than in group A. The levels of interleukin (IL)-4, IL-10, tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ) were significantly higher in groups B–D than in group A. After an ip challenge with B. abortus 544, only group C mice showed a significant level of protection as compared to group A. Overall, these results show that ip immunization with a vaccine candidate lysed by GI24 can effectively protect mice from systemic infection with virulent B. abortus. PMID:27349900

  14. Hydrogen-Rich Saline Attenuates Lipopolysaccharide-Induced Heart Dysfunction by Restoring Fatty Acid Oxidation in Rats by Mitigating C-Jun N-Terminal Kinase Activation.

    PubMed

    Tao, Bingdong; Liu, Lidan; Wang, Ni; Tong, Dongyi; Wang, Wei; Zhang, Jin

    2015-12-01

    Sepsis is common in intensive care units (ICU) and is associated with high mortality. Cardiac dysfunction complicating sepsis is one of the most important causes of this mortality. This dysfunction is due to myocardial inflammation and reduced production of energy by the heart. A number of studies have shown that hydrogen-rich saline (HRS) has a beneficial effect on sepsis. Therefore, we tested whether HRS prevents cardiac dysfunction by increasing cardiac energy. Four groups of rats received intraperitoneal injections of one of the following solutions: normal saline (NS), HRS, lipopolysaccharide (LPS), and LPS plus HRS. Cardiac function was measured by echocardiography 8 h after the injections. Gene and protein expression related to fatty acid oxidation (FAO) were measured by quantitative polymerase chain reaction (PCR) and Western blot analysis. The injection of LPS compromised heart function through decreased fractional shortening (FS) and increased left ventricular diameter (LVD). The addition of HRS increased FS, palmitate triphosphate, and the ratio of phosphocreatinine (PCr) to adenosine triphosphate (ATP) as well as decreasing LVD. The LPS challenge reduced the expression of genes related to FAO, including perioxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), perioxisome proliferator-activated receptor alpha (PPARα), Estrogen-related receptor alpha (ERRα), and their downstream targets, in mRNA and protein level, which were attenuated by HRS. However, HRS had little effect on glucose metabolism. Furthermore, HRS inhibited c-Jun N-terminal kinase (JNK) activation in the rat heart. Inhibition of JNK by HRS showed beneficial effects on LPS-challenged rats, at least in part, by restoring cardiac FAO.

  15. Glial Fibrillary Acidic Protein and Ubiquitin C-Terminal Hydrolase-L1 Are Not Specific Biomarkers for Mild CT-Negative Traumatic Brain Injury.

    PubMed

    Posti, Jussi P; Hossain, Iftakher; Takala, Riikka S K; Liedes, Hilkka; Newcombe, Virginia; Outtrim, Joanne; Katila, Ari J; Frantzén, Janek; Ala-Seppälä, Henna; Coles, Jonathan P; Kyllönen, Anna; Maanpää, Henna-Riikka; Tallus, Jussi; Hutchinson, Peter J; van Gils, Mark; Menon, David K; Tenovuo, Olli

    2017-01-27

    Glial fibrillary acidic protein (GFAP) and ubiquitin C-terminal hydrolase-L1 (UCH-L1) have been studied as potential biomarkers of mild traumatic brain injury (mTBI). We report the levels of GFAP and UCH-L1 in patients with acute orthopedic injuries without central nervous system involvement, and relate them to the type of extracranial injury, head magnetic resonance imaging (MRI) findings, and levels of GFAP and UCH-L1 in patients with CT-negative mTBI. Serum UCH-L1 and GFAP were longitudinally measured from 73 patients with acute orthopedic injury on arrival and on days 1, 2, 3, 7 after admission, and on the follow-up visit 3-10 months after the injury. The injury types were recorded, and 71% patients underwent also head MRI. The results were compared with those found in patients with CT-negative mTBI (n = 93). The levels of GFAP were higher in patients with acute orthopedic trauma than in patients with CT-negative mTBI (p = 0.026) on arrival; however, no differences were found on the following days. The levels of UCH-L1 were not significantly different between these two groups at any measured point of time. Levels of GFAP and UCH-L1 were not able to distinguish patients with CT-negative mTBI from patients with orthopedic trauma. Patients with orthopedic trauma and high levels of UCH-L1 or GFAP values may be falsely diagnosed as having a concomitant mTBI, predisposing them to unwarranted diagnostics and unnecessary brain imaging. This casts a significant doubt on the diagnostic value of GFAP and UCH-L1 in cases with mTBI.

  16. Microsecond Deprotonation of Aspartic Acid and Response of the α/β Subdomain Precede C-Terminal Signaling in the Blue Light Sensor Plant Cryptochrome.

    PubMed

    Thöing, Christian; Oldemeyer, Sabine; Kottke, Tilman

    2015-05-13

    Plant cryptochromes are photosensory receptors that regulate various central aspects of plant growth and development. These receptors consist of a photolyase homology region (PHR) carrying the oxidized flavin adenine dinucleotide (FAD) cofactor, and a cryptochrome C-terminal extension (CCT), which is essential for signaling. Absorption of blue/UVA light leads to formation of the FAD neutral radical as the likely signaling state, and ultimately activates the CCT. Little is known about the signal transfer from the flavin to the CCT. Here, we investigated the photoreaction of the PHR by time-resolved step-scan FT-IR spectroscopy complemented by UV-vis spectroscopy. The first spectrum at 500 ns shows major contributions from the FAD anion radical, which is demonstrated to then be protonated by aspartic acid 396 to the neutral radical within 3.5 μs. The analysis revealed the existence of three intermediates characterized by changes in secondary structure. A marked loss of β-sheet structure is observed in the second intermediate evolving with a time constant of 500 μs. This change is accompanied by a conversion of a tyrosine residue, which is identified as the formation of a tyrosine radical in the UV-vis. The only β-sheet in the PHR is located within the α/β subdomain, ∼25 Å away from the flavin. This subdomain has been previously attributed a role as a putative antenna binding site, but is now suggested to have evolved to a component in the signaling of plant cryptochromes by mediating the interaction with the CCT.

  17. Modeling the Kinetics of Serum Glial Fibrillary Acidic Protein, Ubiquitin Carboxyl-Terminal Hydrolase-L1, and S100B Concentrations in Patients with Traumatic Brain Injury.

    PubMed

    Welch, Robert D; Ellis, Morgan; Lewis, Lawrence M; Ayaz, Syed I; Mika, Valerie H; Millis, Scott; Papa, Linda

    2017-02-27

    Glial fibrillary acidic protein (GFAP), ubiquitin carboxyl-terminal hydrolase-L1 (UCH-L1), and S100B have been shown to be predictive of patients with brain injury. Kinetics of these biomarkers in injured humans have not been extensively examined. This prospective multi-center study included patients with mild-to-moderate traumatic brain injury. Blood samples obtained at enrollment and every 6 h up to 24 h post-injury were assayed for GFAP, UCH-L1, and S100B. Random effects models examined changes in the biomarkers' level over time. A total of 167 patients were enrolled; mean age was 46.0 ± 17.8, 61.1% were male, 143 (85.6%) had a Glasgow Coma Scale score of 15, and 33 (19.8%) had a positive head computed tomography (CT) scan. Baseline median biomarker concentrations for all three were higher among CT-positive patients (p < 0.0001) but GFAP was the only biomarker that significantly increased over time among CT-positive patients relative to CT-negative patients (log transformed values 0.037; 95% confidence interval 0.02, 0.05; p < 0.001), indicating a 3.7% per hour rise in GFAP concentration. There was no significant increase in either UCH-L1 or S100B in CT-positive patients (p = 0.15 and p = 0.47, respectively). GFAP concentrations increased 3.7% per hour among CT-positive patients whereas neither UCH-L1 nor S100B increased, compared with CT-negative patients. The kinetics and temporal profile of GFAP suggest it may be a more robust biomarker to detect patients with positive CT findings, particularly at later post-injury times. Further study is needed to determine if GFAP is a useful test to follow throughout a patient's clinical course.

  18. Acid-labile formylation of amino terminal proline of human immunodeficiency virus type 1 p24(gag) was found by proteomics using two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry.

    PubMed

    Fuchigami, Takashi; Misumi, Shogo; Takamune, Nobutoki; Takahashi, Ichiro; Takama, Michiho; Shoji, Shozo

    2002-05-10

    HIV-1(LAV-1) particles were collected by ultracentrifugation, treated with subtilisin, and then purified by Sepharose CL-4B column chromatography to remove microvesicles. The lysate of the purified human immunodeficiency virus type 1 (HIV-1) particles was subjected to two-dimensional (2D) gel electrophoresis and stained, and the stained spots were excised and digested with trypsin. The resulting peptide fragments were characterized by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Twenty-five proteins were identified as the proteins inside the virion and the acid-labile formyl group of an amino terminal proline residue of HIV-1(LAV-1) p24(gag) was determined by MALDI-TOF MS before and after weak-acid treatments (0.6 N hydrochloric acid) and confirmed by post-source decay (PSD) of the N-formylated N-terminal tryptic peptide (N-formylated Pro(1)-Arg(18)). The role of formylation has been unclear so far, but it is surmised that the acid-labile formylation of HIV-1(LAV-1) p24(gag) may play a critical role in the formation of the HIV-1 core for conferring HIV-1 infectivity.

  19. Expression of a borage desaturase cDNA containing an N-terminal cytochrome b5 domain results in the accumulation of high levels of delta6-desaturated fatty acids in transgenic tobacco.

    PubMed

    Sayanova, O; Smith, M A; Lapinskas, P; Stobart, A K; Dobson, G; Christie, W W; Shewry, P R; Napier, J A

    1997-04-15

    gamma-Linolenic acid (GLA; C18:3 delta(6,9,12)) is a component of the seed oils of evening primrose (Oenothera spp.), borage (Borago officinalis L.), and some other plants. It is widely used as a dietary supplement and for treatment of various medical conditions. GLA is synthesized by a delta6-fatty acid desaturase using linoleic acid (C18:2 delta(9,12)) as a substrate. To enable the production of GLA in conventional oilseeds, we have isolated a cDNA encoding the delta6-fatty acid desaturase from developing seeds of borage and confirmed its function by expression in transgenic tobacco plants. Analysis of leaf lipids from a transformed plant demonstrated the accumulation of GLA and octadecatetraenoic acid (C18:4 delta(6,9,12,15)) to levels of 13.2% and 9.6% of the total fatty acids, respectively. The borage delta6-fatty acid desaturase differs from other desaturase enzymes, characterized from higher plants previously, by the presence of an N-terminal domain related to cytochrome b5.

  20. The role of alkyl chain length of monothiol-terminated alkyl carboxylic acid in the synthesis, characterization, and application of gelatin-g-poly(N-isopropylacrylamide) carriers for antiglaucoma drug delivery.

    PubMed

    Luo, Li-Jyuan; Lai, Jui-Yang

    2017-02-01

    To improve ocular bioavailability and extend pharmacological response, this study aims to investigate the role of alkyl chain length of monothiol-terminated alkyl carboxylic acids in the synthesis, characterization, and application of gelatin-g-poly(N-isopropylacrylamide) (GN) biodegradable in situ gelling carriers for antiglaucoma drug delivery. In the presence of mercaptoacetic acid (MAA), mercaptopropionic acid (MPA), mercaptobutyric acid (MBA), or mercaptohexanoic acid (MHA) as a chain transfer agent, the carboxylic end-capped poly(N-isopropylacrylamide) samples were prepared by free radical polymerization technique. Our results showed that with increasing alkyl chain length, the hydrophobicity of thermo-responsive polymer segments significantly increased, mainly due to an increase in CH stretching frequencies. In addition, the greater hydrophobic association favored the decrease in both phase transition temperature and weight loss of GN copolymers, thereby accelerating their temperature-triggered gelation process and retarding the degradation progress under physiological conditions. The benefits from these features allowed the pilocarpine carriers to increase drug payload and extend drug release. Irrespective of carbon number of monothiol-terminated alkyl carboxylic acid, the synthesized GN materials exhibited high tolerance to corneal endothelial cells without any evidence of inhibited proliferation, viability loss, inflammatory stimulation, and functional abnormality, indicating good biocompatibility. Results of clinical observations and histological examinations demonstrated that the therapeutic efficacies in treating glaucomatous damage are in response to in vivo drug release profiles from various intracamerally injected GN carriers. The research findings suggest the influence of alkyl chain length of chain transfer agent-mediated polymer hydrophobicity and degradability on pharmacological bioavailability and action of pilocarpine in a glaucomatous rabbit

  1. Inhibition of NADPH oxidase activation by synthetic peptides mapping within the carboxyl-terminal domain of small GTP-binding proteins. Lack of amino acid sequence specificity and importance of polybasic motif.

    PubMed

    Joseph, G; Gorzalczany, Y; Koshkin, V; Pick, E

    1994-11-18

    The small GTP-binding protein (G protein) Rac1 is an obligatory participant in the assembly of the superoxide (O2-.)-generating NADPH oxidase complex of macrophages. We investigated the effect of synthetic peptides, mapping within the near carboxyl-terminal domains of Rac1 and of related G proteins, on the activity of NADPH oxidase in a cell-free system consisting of solubilized guinea pig macrophage membrane, a cytosolic fraction enriched in p47phox and p67phox (or total cytosol), highly purified Rac1-GDP dissociation inhibitor for Rho (Rho GDI) complex, and the activating amphiphile, lithium dodecyl sulfate. Peptides Rac1-(178-188) and Rac1-(178-191), but not Rac2-(178-188), inhibited NADPH oxidase activity in a Rac1-dependent system when added prior to or simultaneously with the initiation of activation. However, undecapeptides corresponding to the near carboxyl-terminal domains of RhoA and RhoC and, most notably, a peptide containing the same amino acids as Rac1-(178-188), but in reversed orientation, were also inhibitory. Surprisingly, O2-. production in a Rac2-dependent cell-free system was inhibited by Rac1-(178-188) but not by Rac2-(178-188). Finally, basic polyamino acids containing lysine, histidine, or arginine, also inhibited NADPH oxidase activation. We conclude that inhibition of NADPH oxidase activation by synthetic peptides mapping within the carboxyl-terminal domain of certain small G proteins is not amino acid sequence-specific but related to the presence of a polybasic motif. It has been proposed that such a motif serves as a plasma membrane targeting signal for a number of small G proteins (Hancock, J.F., Paterson, H., and Marshall, C.J. (1990) Cell 63, 133-139).

  2. Aging, Terminal Decline, and Terminal Drop

    ERIC Educational Resources Information Center

    Palmore, Erdman; Cleveland, William

    1976-01-01

    Data from a 20-year longitudinal study of persons over 60 were analyzed by step-wise multiple regression to test for declines in function with age, for terminal decline (linear relationship to time before death), and for terminal drop (curvilinear relationship to time before death). There were no substantial terminal drop effects. (Author)

  3. Electrochemical growth of CoNi and Pt-CoNi soft magnetic composites on an alkanethiol monolayer-modified ITO substrate.

    PubMed

    Escalera-López, D; Gómez, E; Vallés, E

    2015-07-07

    CoNi and Pt-CoNi magnetic layers on indium-tin oxide (ITO) substrates modified by an alkanethiol self-assembled monolayer (SAM) have been electrochemically obtained as an initial stage to prepare semiconducting layer-SAM-magnetic layer hybrid structures. The best conditions to obtain the maximum compactness of adsorbed layers of dodecanethiol (C12-SH) on ITO substrate have been studied using contact angle, AFM, XPS and electrochemical tests. The electrochemical characterization (electrochemical probe or voltammetric response in blank solutions) is fundamental to ensure the maximum blocking of the substrate. Although the electrodeposition process on the SAM-modified ITO substrate is very slow if the blocking of the surface is significant, non-cracked metallic layers of CoNi, with or without a previously electrodeposited seed-layer of platinum, have been obtained by optimizing the deposition potentials. Initial nucleation is expected to take place at the pinhole defects of the C12-SH SAM, followed by a mushroom-like growth regime through the SAM interface that allows the formation of a continuous metallic layer electrically connected to the ITO surface. Due to the potential of the methodology, the preparation of patterned metallic deposits on ITO substrate using SAMs with different coverage as templates is feasible.

  4. Ubiquitous 8 and 29 kDa gold:alkanethiolate cluster compounds: mass-spectrometric determination of molecular formulas and structural implications.

    PubMed

    Chaki, Nirmalya K; Negishi, Yuichi; Tsunoyama, Hironori; Shichibu, Yukatsu; Tsukuda, Tatsuya

    2008-07-09

    The molecular formulas and charge state distributions of thus-far known ubiquitous alkanethiolate-protected gold clusters with core-masses of 8 and 29 kDa were assessed using electrospray ionization mass spectrometry. The 8 and 29 kDa clusters were determined to be composed of single species, [Au38(SCn)24]z and [Au144(SCn)59]z, respectively, with charge states of z >/= 0. Possible geometric structures for Au38(SCn)24 and Au144(SCn)59 are discussed, based on the structures of relevant systems that have been recently determined experimentally and theoretically: [Au25(SR)18]- and Au102(SR)44, in which the Au cores are protected by monomers [-SR-Au-SR-] and/or dimers [-SR-Au-SR-Au-SR-]. Their preferential formation and chemical robustness are proposed as being associated with high stability due to geometric factors, while the Au-thiolate interface takes on common motifs regardless of the underlying Au core.

  5. Facile one-pot synthesis of 4,5-disubstituted 1,2,3-(NH)-triazoles through Sonogashira coupling/1,3-dipolar cycloaddition of acid chlorides, terminal acetylenes, and sodium azide.

    PubMed

    Li, Jihui; Wang, Dong; Zhang, Yuanqing; Li, Jiting; Chen, Baohua

    2009-07-16

    A novel and efficient way of synthesizing 4,5-disubstituted-1,2,3-(NH)-triazoles through palladium-catalyzed and ultrasonic promoted Sonogashira coupling/1,3-dipolar cycloaddition of acid chlorides, terminal acetylenes, and sodium azide in one pot is developed. The reaction scope is quite general, and the methodology can produce excellent yields. The regioselective 1,4,5-trisubstituted-1,2,3-(NH)-triazoles can be made easily from 4,5-disubstituted-1,2,3-(NH)-triazoles.

  6. Amyloidogenic properties of a D/N mutated 12 amino acid fragment of the C-terminal domain of the Cholesteryl-Ester Transfer Protein (CETP).

    PubMed

    García-González, Victor; Mas-Oliva, Jaime

    2011-01-01

    The cholesteryl-ester transfer protein (CETP) facilitates the transfer of cholesterol esters and triglycerides between lipoproteins in plasma where the critical site for its function is situated in the C-terminal domain. Our group has previously shown that this domain presents conformational changes in a non-lipid environment when the mutation D(470)N is introduced. Using a series of peptides derived from this C-terminal domain, the present study shows that these changes favor the induction of a secondary β-structure as characterized by spectroscopic analysis and fluorescence techniques. From this type of secondary structure, the formation of peptide aggregates and fibrillar structures with amyloid characteristics induced cytotoxicity in microglial cells in culture. These supramolecular structures promote cell cytotoxicity through the formation of reactive oxygen species (ROS) and change the balance of a series of proteins that control the process of endocytosis, similar to that observed when β-amyloid fibrils are employed. Therefore, a fine balance between the highly dynamic secondary structure of the C-terminal domain of CETP, the net charge, and the physicochemical characteristics of the surrounding microenvironment define the type of secondary structure acquired. Changes in this balance might favor misfolding in this region, which would alter the lipid transfer capacity conducted by CETP, favoring its propensity to substitute its physiological function.

  7. Spatial structure of oligopeptide PAP(248-261), the N-terminal fragment of the HIV enhancer prostatic acid phosphatase peptide PAP(248-286), in aqueous and SDS micelle solutions

    NASA Astrophysics Data System (ADS)

    Blokhin, Dmitriy S.; Filippov, Andrei V.; Antzutkin, Oleg N.; Karataeva, Farida Kh.; Klochkov, Vladimir V.

    2014-07-01

    Prostatic acid phosphatase (PAP) is an enzyme that facilitates infection of cells by HIV. Its peptide fragment PAP(248-286) forms amyloid fibrils known as SEVI, which enhance attachment of the virus by viral adhesion to the host cell prior to receptor-specific binding via reducing the electrostatic repulsion between the membranes of the virus and the target cell. The secondary structure of PAP(248-286) in aqueous and SDS solutions can be divided into an N-terminal disordered region, an α-helical central part and an α/310-helical C-terminal region (Nanga et al., 2009). In this work, we used NMR spectroscopy to study the spatial structure of the isolated N-terminal fragment of PAP(248-286), PAP(248-261) (GIHKQKEKSRLQGG), in aqueous and SDS micelle solutions. Formation of a PAP(248-261)-SDS complex was confirmed by chemical shift alterations in the 1H NMR spectra of the peptide, as well as by the signs and values of Nuclear Overhauser Effect (NOE). In addition, the PAP(248-261) peptide does not form any specified secondary structure in either aqueous or SDS solutions.

  8. High-level expression and in vitro mutagenesis of a fibrillogenic 109-amino-acid C-terminal fragment of Alzheimer's-disease amyloid precursor protein.

    PubMed Central

    Gardella, J E; Gorgone, G A; Candela, L; Ghiso, J; Castaño, E M; Frangione, B; Gorevic, P D

    1993-01-01

    We amplified DNA encoding the 3' 109 codons of Alzheimer's-disease amyloid precursor protein (APP) inclusive of the beta protein (A beta) and cytoplasmic domains from cDNA using oligonucleotide primers designed to facilitate cloning into the T7 expression vector pT7Ad23K13. We also modified this construct to generate recombinant molecules incorporating two recently described APP mutants by site-directed mutagenesis. Both native C109 (deletion construct inclusive of the C-terminal 109 residues of APP) and constructs with a single mutation at codon 642 (T-->G, resulting in a substitution of glycine for valine) or a double mutation at codons 595 (G-->T, substituting asparagine for lysine) and 596 (A-->C, substituting leucine for methionine) were expressed in Escherichia coli to levels of 5-20% of total bacterial protein after induction. The major constituent of expressed C109 protein had an apparent molecular mass of 16-18 kDa by SDS/PAGE and appeared to be the full-length construct by size and N-terminal microsequencing. Also present was a 4-5 kDa species that co-purified with C109, constituting only approximately 1% of expressed protein, which was revealed by Western-blot analysis with antibodies specific for A beta epitopes and after biotinylation of purified recombinant C109. This fragment shared N-terminal sequence with, and appeared to arise by proteolysis of, full-length C109 in biosynthetic labelling experiments. C109 spontaneously precipitated after dialysis against NaCl or water, and with prolonged (> 20 weeks) standing was found by electron microscopy to contain a minor (< 5%) fibrillar component that was reactive with antibodies to a C-terminal epitope of APP. Recombinant C109 appears to duplicate some of the biochemical and physicochemical properties of C-terminal A beta-inclusive fragments of APP that have been found in transfected cells, brain cortex and cerebral microvessels. Images Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 PMID

  9. Identification, characterization, and developmental expression of a novel alpha 2-->8-KDN-transferase which terminates elongation of alpha 2-->8-linked oligo-polysialic acid chain synthesis in trout egg polysialoglycoproteins.

    PubMed

    Angata, T; Kitazume, S; Terada, T; Kitajima, K; Inoue, S; Troy, F A; Inoue, Y

    1994-10-01

    A novel glycosyltransferase which catalyses transfer of deaminated neuraminic acid, KDN (2-keto-3-deoxy-D-glycero-D-galacto-nononic acid) from CMP-KDN to the non-reducing termini of oligo-polysialyl chains of polysialoglycoprotein (PSGP), was discovered in the ovary of rainbow trout (Oncorhynchus mykiss). The KDN-transferase activity was optimal at neutral pH, and stimulated 2 to 2.5-fold by 2-5 mM Mg2+ or Mn2+. Expression of KDN-transferase was developmentally regulated in parallel with expression of the alpha 2-->8-polysialyltransferase, which catalyses synthesis of the oligo-polysialyl chains in PSGP. Incorporation of the KDN residues into the oligo-polysialyl chains prevented their further elongation, resulting in 'capping' of the oligo-polysialyl chains. This is the first example of a glycosyltransferase that catalyses termination of alpha 2-->8-polysialylation in glycoproteins.

  10. [Expression levels of ubiquitin C-terminal hydrolase-L1 and serum glial fibrillary acidic protein and its clinical significance in patients with acute cerebral infarction].

    PubMed

    Hu, Chongling; Yang, Xinling; Mao, Deqiang; Lou, Silong; Dai, Qinbi; Chen, Jie; Cheng, Xing; Wang, Shiqiang

    2017-03-28

    目的:观察急性脑梗死患者血清泛素羧基末端水解酶-1(ubiquitin C-terminal hydrolase-L1,UCH-L1)和血清胶质纤维酸性蛋白(serum glial fibrillary acidic protein,GFAP)的临床表达水平,并探讨二者对脑梗死患者的临床意义。
方法:选取重庆市肿瘤医院在2014年1月至2016年2月期间收治的80例急性脑梗死患者作为观察组,另选取同时段来院做体格检查的80例健康者作为对照组。分别检测两组研究对象的血清UCH-L1和GFAP的表达水平。结果:UCH-L1诊断脑梗死的敏感度为75.0%,特异度为87.5%;GFAP诊断脑梗死的敏感度为81.3%,特异度为 90.0%。UCH-L1和GFAP的受试者工作特征(receiver operating characteristic,ROC)曲线下面积分别为0.670及0.757。两组研究对象在年龄、性别、饮酒、吸烟、糖尿病、高脂血症等一般情况中比较,差异无统计学意义(P>0.05);观察组患者患高血压的比例明显高于对照组(P<0.05);经Spearson/Pearson分析显示血清UCH-L1与GFAP水平与高血压呈正比,与性别、年龄、糖尿病、高血脂、饮酒、吸烟等因素无相关性;观察组患者不同发病时间一般资料的比较,差异无统计学意义(P>0.05),血清UCH-L1和GFAP表达水平明显高于对照组(P<0.05);在不同发病时间两组患者血清UCH-L1和GFAP表达水平差异无统计学意义(P>0.05);轻、中、重型3组患者的血清UCH-L1和GFAP表达水平高于对照组(P<0.05);中、重型患者血清UCH-L1和GFAP表达水平高于轻型(P<0.05);观察组患者在不同发病时间里血清UCH-L1和GFAP表达水平与梗死灶大小差异有统计学意义(P<0.05);Pearson相关性分析结果示血清UCH-L1和GFAP表达水平呈正相关(r=0.634,P=0.001)。结论:在急性脑梗死患者中早期血清UCH-L1和GFAP的表达水平明显升高,与脑梗死的病情严重程度有一定的相关性,可为临床上早期诊断及治疗提供依据。.

  11. Identification of Surface Debye Temperature of an Alkanethiol Self Assembled Monolayer on Au(111) by Low Energy Helium Diffraction

    NASA Astrophysics Data System (ADS)

    West, Joshua; Camillone, Nicholas, III; Schwartz, Peter

    2005-03-01

    Using Low Energy Atomic Diffraction (LEAD), a nonperturbative and totally unpenetrating surface characterization technique, we have conducted measurements on the surface of self assembling monolayers (SAMs) of decanethiol on a Au(111) surface. Debye-Waller attenuation measurements were taken for substrate temperatures from 14.5 K to 110 K. For the lowest substrate temperatures, thermal Debye-Waller attenuation decreased consistent with a surface Debye temperature of about 100 K. The excellent order demonstrated by these particular data provided high resolution to six orders of the hexagonal peak (corresponding to the rt3 x rt3 thiol mesh). These data from higher order diffraction peaks allows us to more precisely measure the lateral thermal vibration of the terminal methyl groups, which is considerably less than previously reported

  12. A Plasma Display Terminal.

    ERIC Educational Resources Information Center

    Stifle, Jack

    A graphics terminal designed for use as a remote computer input/output terminal is described. Although the terminal is intended for use in teaching applications, it has several features which make it useful in many other computer terminal applications. These features include: a 10-inch square plasma display panel, permanent storage of information…

  13. Acetylene terminated aspartimides and resins therefrom

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M. (Inventor); Connell, John W. (Inventor); Havens, Stephen J. (Inventor)

    1989-01-01

    Acetylene terminated aspartimides are prepared using two methods. In the first, an amino-substituted aromatic acetylene is reacted with an aromatic bismaleimide in a solvent of glacial acetic acid and/or m-cresol. In the second method, an aromatic diamine is reacted with an ethynyl containing maleimide, such an N-(3-ethynyl phenyl) maleimide, in a solvent of glacial acetic acid and/or m-cresol. In addition, acetylene terminated aspartimides are blended with various acetylene terminated oligomers and polymers to yield composite materials exhibiting improved mechanical properties.

  14. A single amino acid change of translation termination factor eRF1 switches between bipotent and omnipotent stop-codon specificity.

    PubMed

    Eliseev, Boris; Kryuchkova, Polina; Alkalaeva, Elena; Frolova, Ludmila

    2011-01-01

    In eukaryotes a single class-1 translation termination factor eRF1 decodes the three stop codons: UAA, UAG and UGA. Some ciliates, like Euplotes, have a variant code, and here eRF1s exhibit UAR-only specificity, whereas UGA is reassigned as a sense codon. Since eukaryote eRF1 stop-codon recognition is associated with its N-terminal domain, structural features should exist in the N domain of ciliate eRF1s that restrict their stop-codon specificity. Using an in vitro reconstituted eukaryotic translation system we demonstrate here that a chimeric eRF1 composed of the N domain of Euplotes aediculatus eRF1 fused to the MC domains of human eRF1 exhibits UAR-only specificity. Functional analysis of eRF1 chimeras constructed by swapping Euplotes N domain sequences with the cognate regions from human eRF1 as well as site-directed mutagenesis of human eRF1 highlighted the crucial role of the alanine residue in position 70 of E. aediculatus eRF1 in restricting UGA decoding. Switching the UAR-only specificity of E. aediculatus eRF1 to omnipotent mode is due to a single point mutation. Furthermore, we examined the influence of eRF3 on the ability of chimeric and mutant eRF1s to induce peptide release in response to different stop codons.

  15. Retinoic acids acting through retinoid receptors protect hippocampal neurons from oxygen-glucose deprivation-mediated cell death by inhibition of c-jun-N-terminal kinase and p38 mitogen-activated protein kinase.

    PubMed

    Shinozaki, Y; Sato, Y; Koizumi, S; Ohno, Y; Nagao, T; Inoue, K

    2007-06-15

    Retinoic acids (RAs), including all-trans retinoic acid (ATRA) and 9-cis retinoic acid (9-cis RA), play fundamental roles in a variety of physiological events in vertebrates, through their specific nuclear receptors: retinoic acid receptor (RAR) and retinoid X receptor (RXR). Despite the physiological importance of RA, their functional significance under pathological conditions is not well understood. We examined the effect of ATRA on oxygen/glucose-deprivation/reperfusion (OGD/Rep)-induced neuronal damage in cultured rat hippocampal slices, and found that ATRA significantly reduced neuronal death. The cytoprotective effect of ATRA was observed not only in cornu ammonis (CA) 1 but also in CA2 and dentate gyrus (DG), and was attenuated by selective antagonists for RAR or RXR. By contrast, in the CA3 region, no protective effects of ATRA were observed. The OGD/Rep also increased phosphorylated forms of c-jun-N-terminal kinase (P-JNK) and p38 (P-p38) in hippocampus, and specific inhibitors for these kinases protected neurons. ATRA prevented the increases in P-JNK and P-p38 after OGD/Rep, as well as the decrease in NeuN and its shrinkage, all of which were inhibited by antagonists for RAR or RXR. These findings suggest that the ATRA signaling via retinoid receptors results in the inhibition of JNK and p38 activation, leading to the protection of neurons against OGD/Rep-induced damage in the rat hippocampus.

  16. Acidic pH triggers conformational changes at the NH2-terminal propeptide of the precursor of pulmonary surfactant protein B to form a coiled coil structure.

    PubMed

    Bañares-Hidalgo, A; Pérez-Gil, J; Estrada, P

    2014-07-01

    Pulmonary surfactant protein SP-B is synthesized as a larger precursor, proSP-B. We report that a recombinant form of human SP-BN forms a coiled coil structure at acidic pH. The protonation of a residue with pK=4.8±0.06 is the responsible of conformational changes detected by circular dichroism and intrinsic fluorescence emission. Sedimentation velocity analysis showed protein oligomerisation at any pH condition, with an enrichment of the species compatible with a tetramer at acidic pH. Low 2,2,2,-trifluoroethanol concentration promoted β-sheet structures in SP-BN, which bind Thioflavin T, at acidic pH, whereas it promoted coiled coil structures at neutral pH. The amino acid stretch predicted to form β-sheet parallel association in SP-BN overlaps with the sequence predicted by several programs to form coiled coil structure. A synthetic peptide ((60)W-E(85)) designed from the sequence of the amino acid stretch of SP-BN predicted to form coiled coil structure showed random coil conformation at neutral pH but concentration-dependent helical structure at acidic pH. Sedimentation velocity analysis of the peptide indicated monomeric state at neutral pH (s20, w=0.55S; Mr~3kDa) and peptide association (s20, w=1.735S; Mr=~14kDa) at acidic pH, with sedimentation equilibrium fitting to a Monomer-Nmer-Mmer model with N=6 and M=4 (Mr=14692Da). We propose that protein oligomerisation through coiled-coil motifs could then be a general feature in the assembly of functional units in saposin-like proteins in general and in the organization of SP-B in a functional surfactant, in particular.

  17. Effect of maternal aging on transgene heritability in transgenic founder mice derived from zygotes microinjected with retroviral long terminal repeat-containing recombinant deoxyribonucleic acid.

    PubMed

    Wang, T H; Yang, W K; Hoyt, P R; Ch'ang, L Y; Savin, T J

    1993-05-01

    To determine the stability of artificially introduced recombinant DNA in the mouse germline throughout the reproductive life, founder mice derived from fertilized eggs injected with retroviral long-terminal-repeat-containing recombinant DNAs were mated with congenic FVB/N mice. Tail DNA of all progeny were screened and restriction fragment patterns of the transgenes were examined. Litter size and percentage of transgene transmission at various reproductive age periods were analyzed. Microinjection of 1737 eggs with four different recombinant DNAs resulted in 12 female and 11 male transgenic mice; 2 males were sterile and the remaining 21 mice served as founders to produce 1087 F1 progeny. With increasing parental age, litter size decreased generally. The percentage of progeny inheriting the transgenes declined markedly with increasing aging of 4 female founders; this aging effect was not observed in male founders (p < 0.005). No apparent change in transgenes was detected in progeny from late reproductive stages.

  18. N-Terminal Fatty Acid Substitution Increases the Leishmanicidal Activity of CA(1-7)M(2-9), a Cecropin-Melittin Hybrid Peptide

    PubMed Central

    Chicharro, Cristina; Granata, Cesare; Lozano, Rosario; Andreu, David; Rivas, Luis

    2001-01-01

    In order to improve the leishmanicidal activity of the synthetic cecropin A-melittin hybrid peptide CA(1-7)M(2-9) (KWKLFKKIGAVLKVL-NH2), a systematic study of its acylation with saturated linear fatty acids was carried out. Acylation of the Nɛ-7 lysine residue led to a drastic decrease in leishmanicidal activity, whereas acylation at lysine 1, in either the α or the ɛ NH2 group, increased up to 3 times the activity of the peptide against promastigotes and increased up to 15 times the activity of the peptide against amastigotes. Leishmanicidal activity increased with the length of the fatty acid chain, reaching a maximum for the lauroyl analogue (12 carbons). According to the fast kinetics, dissipation of membrane potential, and parasite membrane permeability to the nucleic acid binding probe SYTOX green, the lethal mechanism was directly related to plasma membrane permeabilization. PMID:11502512

  19. 55 Amino acid linker between helicase and carboxyl terminal domains of RIG-I functions as a critical repression domain and determines inter-domain conformation.

    PubMed

    Kageyama, Maiko; Takahasi, Kiyohiro; Narita, Ryo; Hirai, Reiko; Yoneyama, Mitsutoshi; Kato, Hiroki; Fujita, Takashi

    2011-11-11

    In virus-infected cells, viral RNA with non-self structural pattern is recognized by DExD/Hbox RNA helicase, RIG-I. Once RIG-I senses viral RNA, it triggers a signaling cascade, resulting in the activation of genes including type I interferon, which activates antiviral responses. Overexpression of N-terminal caspase activation and recruitment domain (CARD) is sufficient to activate signaling; however basal activity of full-length RIG-I is undetectable. The repressor domain (RD), initially identified as a.a. 735-925, is responsible for diminished basal activity; therefore, it is suggested that RIG-I is under auto-repression in uninfected cells and the repression is reversed upon its encounter with viral RNA. In this report, we further delimited RD to a.a. 747-801, which corresponds to a linker connecting the helicase and the C-terminal domain (CTD). Alanine substitutions of the conserved residues in the linker conferred constitutive activity to full-length RIG-I. We found that the constitutive active mutants do not exhibit ATPase activity, suggesting that ATPase is required for de-repression but not signaling itself. Furthermore, trypsin digestion of recombinant RIG-I revealed that the wild-type, but not linker mutant conforms to the trypsin-resistant structure, containing CARD and helicase domain. The result strongly suggests that the linker is responsible for maintaining RIG-I in a "closed" structure to minimize unwanted production of interferon in uninfected cells. These findings shed light on the structural regulation of RIG-I function.

  20. Expression of Ceramide Synthase 6 Transcriptionally Activates Acid Ceramidase in a c-Jun N-terminal Kinase (JNK)-dependent Manner*

    PubMed Central

    Tirodkar, Tejas S.; Lu, Ping; Bai, Aiping; Scheffel, Matthew J.; Gencer, Salih; Garrett-Mayer, Elizabeth; Bielawska, Alicja; Ogretmen, Besim; Voelkel-Johnson, Christina

    2015-01-01

    A family of six ceramide synthases with distinct but overlapping substrate specificities is responsible for generation of ceramides with acyl chains ranging from ∼14–26 carbons. Ceramide synthase 6 (CerS6) preferentially generates C14- and C16-ceramides, and we have previously shown that down-regulation of this enzyme decreases apoptotic susceptibility. In this study, we further evaluated how increased CerS6 expression impacts sphingolipid composition and metabolism. Overexpression of CerS6 in HT29 colon cancer cells resulted in increased apoptotic susceptibility and preferential generation of C16-ceramide, which occurred at the expense of very long chain, saturated ceramides. These changes were also reflected in sphingomyelin composition. HT-CerS6 cells had increased intracellular levels of sphingosine, which is generated by ceramidases upon hydrolysis of ceramide. qRT-PCR analysis revealed that only expression of acid ceramidase (ASAH1) was increased. The increase in acid ceramidase was confirmed by expression and activity analyses. Pharmacological inhibition of JNK (SP600125) or curcumin reduced transcriptional up-regulation of acid ceramidase. Using an acid ceramidase promoter driven luciferase reporter plasmid, we demonstrated that CerS1 has no effect on transcriptional activation of acid ceramidase and that CerS2 slightly but significantly decreased the luciferase signal. Similar to CerS6, overexpression of CerS3–5 resulted in an ∼2-fold increase in luciferase reporter gene activity. Exogenous ceramide failed to induce reporter activity, while a CerS inhibitor and a catalytically inactive mutant of CerS6 failed to reduce it. Taken together, these results suggest that increased expression of CerS6 can mediate transcriptional activation of acid ceramidase in a JNK-dependent manner that is independent of CerS6 activity. PMID:25839235

  1. Expression of Ceramide Synthase 6 Transcriptionally Activates Acid Ceramidase in a c-Jun N-terminal Kinase (JNK)-dependent Manner.

    PubMed

    Tirodkar, Tejas S; Lu, Ping; Bai, Aiping; Scheffel, Matthew J; Gencer, Salih; Garrett-Mayer, Elizabeth; Bielawska, Alicja; Ogretmen, Besim; Voelkel-Johnson, Christina

    2015-05-22

    A family of six ceramide synthases with distinct but overlapping substrate specificities is responsible for generation of ceramides with acyl chains ranging from ∼14-26 carbons. Ceramide synthase 6 (CerS6) preferentially generates C14- and C16-ceramides, and we have previously shown that down-regulation of this enzyme decreases apoptotic susceptibility. In this study, we further evaluated how increased CerS6 expression impacts sphingolipid composition and metabolism. Overexpression of CerS6 in HT29 colon cancer cells resulted in increased apoptotic susceptibility and preferential generation of C16-ceramide, which occurred at the expense of very long chain, saturated ceramides. These changes were also reflected in sphingomyelin composition. HT-CerS6 cells had increased intracellular levels of sphingosine, which is generated by ceramidases upon hydrolysis of ceramide. qRT-PCR analysis revealed that only expression of acid ceramidase (ASAH1) was increased. The increase in acid ceramidase was confirmed by expression and activity analyses. Pharmacological inhibition of JNK (SP600125) or curcumin reduced transcriptional up-regulation of acid ceramidase. Using an acid ceramidase promoter driven luciferase reporter plasmid, we demonstrated that CerS1 has no effect on transcriptional activation of acid ceramidase and that CerS2 slightly but significantly decreased the luciferase signal. Similar to CerS6, overexpression of CerS3-5 resulted in an ∼2-fold increase in luciferase reporter gene activity. Exogenous ceramide failed to induce reporter activity, while a CerS inhibitor and a catalytically inactive mutant of CerS6 failed to reduce it. Taken together, these results suggest that increased expression of CerS6 can mediate transcriptional activation of acid ceramidase in a JNK-dependent manner that is independent of CerS6 activity.

  2. Effet de l'acide ascorbique sur la détermination du plomb dans des matrices végétales par ETA-AAS

    NASA Astrophysics Data System (ADS)

    Hoenig, Michel; Van Hoeyweghen, Paul

    Sulphuric acid used in wet oxidation of plant material and the matrix elements are responsible for a strong suppression of lead absorption signals and for the poor reproducibility of the measurements with ETA-AAS. Addition of ascorbic acid to samples (2% m/V) provides an enhancement in sensitivity by more than 200% and leads to acceptable values of the relative error. The results obtained with the 283.3 nm line are better than those obtained with the 217.0 nm line.

  3. Addition of an N-terminal epitope tag significantly increases the activity of plant fatty acid desaturases expressed in yeast cells

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Saccharomyces cerevisiae shows great potential for development of bioreactor systems geared towards the production of high-value lipids such as polyunsaturated omega-3 fatty acids, the yields of which are largely dependent on the activity of ectopically-expressed enzymes. Here we show that the addit...

  4. Enhancement of Ganoderic Acid Accumulation by Overexpression of an N-Terminally Truncated 3-Hydroxy-3-Methylglutaryl Coenzyme A Reductase Gene in the Basidiomycete Ganoderma lucidum

    PubMed Central

    Xu, Jun-Wei; Xu, Yi-Ning

    2012-01-01

    Ganoderic acids produced by Ganoderma lucidum, a well-known traditional Chinese medicinal mushroom, exhibit antitumor and antimetastasis activities. Genetic modification of G. lucidum is difficult but critical for the enhancement of cellular accumulation of ganoderic acids. In this study, a homologous genetic transformation system for G. lucidum was developed for the first time using mutated sdhB, encoding the iron-sulfur protein subunit of succinate dehydrogenase, as a selection marker. The truncated G. lucidum gene encoding the catalytic domain of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) was overexpressed by using the Agrobacterium tumefaciens-mediated transformation system. The results showed that the mutated sdhB successfully conferred carboxin resistance upon transformation. Most of the integrated transfer DNA (T-DNA) appeared as a single copy in the genome. Moreover, deregulated constitutive overexpression of the HMGR gene led to a 2-fold increase in ganoderic acid content. It also increased the accumulation of intermediates (squalene and lanosterol) and the upregulation of downstream genes such as those of farnesyl pyrophosphate synthase, squalene synthase, and lanosterol synthase. This study demonstrates that transgenic basidiomycete G. lucidum is a promising system to achieve metabolic engineering of the ganoderic acid pathway. PMID:22941092

  5. Acquisition of a novel eleven amino acid insertion directly N-terminal to a tetrabasic cleavage site confers intracellular cleavage of an H7N7 influenza virus hemagglutinin

    SciTech Connect

    Hamilton, Brian S.; Sun, Xiangjie; Chung, Changik; Whittaker, Gary R.

    2012-12-05

    A critical feature of highly pathogenic avian influenza viruses (H5N1 and H7N7) is the efficient intracellular cleavage of the hemagglutinin (HA) protein. H7N7 viruses also exist in equine species, and a unique feature of the equine H7N7 HA is the presence of an eleven amino acid insertion directly N-terminal to a tetrabasic cleavage site. Here, we show that three histidine residues within the unique insertion of the equine H7N7 HA are essential for intracellular cleavage. An asparagine residue within the insertion-derived glycosylation site was also found to be essential for intracellular cleavage. The presence of the histidine residues also appear to be involved in triggering fusion, since mutation of the histidine residues resulted in a destabilizing effect. Importantly, the addition of a tetrabasic site and the eleven amino acid insertion conferred efficient intracellular cleavage to the HA of an H7N3 low pathogenicity avian influenza virus. Our studies show that acquisition of the eleven amino acid insertion offers an alternative mechanism for intracellular cleavage of influenza HA.

  6. Ischemia-Modified Albumin as a Marker of Acute Coronary Syndrome: The Case for Revising the Concept of “N-Terminal Modification” to “Fatty Acid Occupation” of Albumin

    PubMed Central

    Oran, Bulent

    2017-01-01

    Ischemia-modified albumin (IMA) is assumed “N-terminal modified” albumin which is generated immediately following myocardial ischemia. The diagnosis of IMA is based on reduced cobalt binding affinity to albumin which is attributed mainly to incapability of cobalt to bind at albumin's modified N-terminus. Although the albumin cobalt binding test was accepted as a potentially powerful marker for discriminating acute coronary syndrome from nonischemic chest pain, its usefulness has been brought into question in recent years. Patients with acutely ischemic myocardium exhibit a rapid increase in serum levels of fatty acids (FAs). Almost all released FAs are strongly bound to albumin which create conformational changes in the protein with resultant reduced cobalt binding affinity. There is a clear metabolic and temporal relationship between IMA measured via albumin cobalt binding testing and serum levels of FAs. In line with what has been suggested recently in the literature, we conclude that a shift from the concept of “N-terminal modified” to “FA-occupied” albumin is required, as this better describes IMA in patients with acute coronary syndrome. We also offer “oxidation modified albumin, OMA,” which is conceptually different from the “FA-occupied” IMA, to describe modification of albumin in chronic disease associated with increased oxidative stress. PMID:28356609

  7. Signal enhancement for gene detection based on a redox reaction of [Fe(CN)(6)](4-) mediated by ferrocene at the terminal of a peptide nucleic acid as a probe with hybridization-amenable conformational flexibility.

    PubMed

    Aoki, Hiroshi; Tao, Hiroaki

    2008-07-01

    Electrochemically enhanced DNA detection was demonstrated by utilizing the couple of a synthesized ferrocene-terminated peptide nucleic acid (PNA) with a cysteine anchor and a sacrificial electron donor [Fe(CN)(6)](4-). DNA detection sensors were prepared by modifying a gold electrode surface with a mixed monolayer of the probe PNA and 11-hydroxy-1-undecanethiol (11-HUT), protecting [Fe(CN)(6)](4-) from any unexpected redox reaction. Before hybridization, the terminal ferrocene moiety of the probe was subject to a redox reaction due to the flexible probe structure and, in the presence of [Fe(CN)(6)](4-), the observed current was amplified based on regeneration of the ferrocene moiety. Hybridization decreased the redox current of the ferrocene. This occurred because hybridization rigidified the probe structure: the ferrocene moiety was then removed from the electrode surface, and the redox reaction of [Fe(CN)(6)](4-) was again prevented. The change in the anodic current before and after hybridization was enhanced 1.75-fold by using the electron donor [Fe(CN)(6)](4-). Sequence-specific detection of the complementary target DNA was also demonstrated.

  8. Unsaturated fatty acids as high-affinity ligands of the C-terminal Per-ARNT-Sim domain from the Hypoxia-inducible factor 3α

    PubMed Central

    Fala, Angela M.; Oliveira, Juliana F.; Adamoski, Douglas; Aricetti, Juliana A.; Dias, Marilia M.; Dias, Marcio V. B.; Sforça, Maurício L.; Lopes-de-Oliveira, Paulo S.; Rocco, Silvana A.; Caldana, Camila; Dias, Sandra M. G.; Ambrosio, Andre L. B.

    2015-01-01

    Hypoxia-inducible transcription factors (HIF) form heterodimeric complexes that mediate cell responses to hypoxia. The oxygen-dependent stability and activity of the HIF-α subunits is traditionally associated to post-translational modifications such as hydroxylation, acetylation, ubiquitination, and phosphorylation. Here we report novel evidence showing that unsaturated fatty acids are naturally occurring, non-covalent structural ligands of HIF-3α, thus providing the initial framework for exploring its exceptional role as a lipid sensor under hypoxia. PMID:26237540

  9. Unsaturated fatty acids as high-affinity ligands of the C-terminal Per-ARNT-Sim domain from the Hypoxia-inducible factor 3α.

    PubMed

    Fala, Angela M; Oliveira, Juliana F; Adamoski, Douglas; Aricetti, Juliana A; Dias, Marilia M; Dias, Marcio V B; Sforça, Maurício L; Lopes-de-Oliveira, Paulo S; Rocco, Silvana A; Caldana, Camila; Dias, Sandra M G; Ambrosio, Andre L B

    2015-08-03

    Hypoxia-inducible transcription factors (HIF) form heterodimeric complexes that mediate cell responses to hypoxia. The oxygen-dependent stability and activity of the HIF-α subunits is traditionally associated to post-translational modifications such as hydroxylation, acetylation, ubiquitination, and phosphorylation. Here we report novel evidence showing that unsaturated fatty acids are naturally occurring, non-covalent structural ligands of HIF-3α, thus providing the initial framework for exploring its exceptional role as a lipid sensor under hypoxia.

  10. A functional role of the C-terminal 42 amino acids of SUR2A and SUR2B in the physiology and pharmacology of cardiovascular ATP-sensitive K(+) channels.

    PubMed

    Yamada, Mitsuhiko; Kurachi, Yoshihisa

    2005-07-01

    The ATP-sensitive K(+) (K(ATP)) channel is composed of four pore-forming Kir6.2 subunits and four sulfonylurea receptors (SUR). Intracellular ATP inhibits K(ATP) channels through Kir6.2. SUR is an ABC protein bearing transmembrane domains and two nucleotide-binding domains (NBD1 and NBD2). SUR increases the open probability of K(ATP) channels by interacting with ATP and ADP through NBDs and with K(+) channel openers such as nicorandil through its transmembrane domain. Because NBDs and the drug receptor allosterically interact with each other, nucleotides and drugs probably activate K(ATP) channels by causing the same conformational change of SUR. SUR2A and SUR2B have the identical drug receptor and NBDs and differ only in the C-terminal 42 amino acids (C42). Nonetheless, nicorandil ~100 times more potently activates SUR2B/Kir6.2 than SUR2A/Kir6.2 channels. Based on our allosteric model, we have analyzed the interaction between NBDs and the drug receptor in SUR2A and SUR2B and found that both nucleotide-bound NBD1 and NBD2 more strongly induce the conformational change in SUR2B than SUR2A. Therefore, C42 modulates the function of not only NBD2 which is close to C42 in a primary structure but NBD1 which is more than 630 amino acid N-terminal to C42. This raises the possibility that in the presence of nucleotides, NBD1 and NBD2 dimerize to induce the conformational change and that the dimerization enables C42 to gain access to both NBDs. Modulation of the nucleotide-NBD1 and -NBD2 interactions by C42 would determine the stability of the nucleotide-dependent dimer and thus, the physiological and pharmacological properties of K(ATP) channels.

  11. Deletion of the carboxyl-terminal region of 1-aminocyclopropane-1-carboxylic acid synthase, a key protein in the biosynthesis of ethylene, results in catalytically hyperactive, monomeric enzyme.

    PubMed

    Li, N; Mattoo, A K

    1994-03-04

    1-Aminocyclopropane-1-carboxylic acid (ACC) synthase is a key enzyme regulating biosynthesis of the plant hormone ethylene. The expression of an enzymatically active, wound-inducible tomato (Lycopersicon esculentum L. cv Pik-Red) ACC synthase (485 amino acids long) in a heterologous Escherichia coli system allowed us to study the importance of hypervariable COOH terminus in enzymatic activity and protein conformation. We constructed several deletion mutants of the gene, expressed these in E. coli, purified the protein products to apparent homogeneity, and analyzed both conformation and enzyme kinetic parameters of the wild-type and truncated ACC syntheses. Deletion of the COOH terminus through Arg429 results in complete inactivation of the enzyme. Deletion of 46-52 amino acids from the COOH terminus results in an enzyme that has nine times higher affinity for the substrate S-adenosylmethionine than the wild-type enzyme. The highly efficient, truncated ACC synthase was found to be a monomer of 52 +/- 1.8 kDa as determined by gel filtration, whereas the wild-type ACC synthase, analyzed under similar conditions, is a dimer. These results demonstrate that the non-conserved COOH terminus of ACC synthase affects its enzymatic function as well as dimerization.

  12. ACTS Mobile Terminals

    NASA Technical Reports Server (NTRS)

    Abbe, Brian S.; Agan, Martin J.; Jedrey, Thomas C.

    1997-01-01

    The development of the Advanced Communications Technology Satellite (ACTS) Mobile Terminal (AMT) and its follow-on, the Broadband Aeronautical Terminal (BAT), have provided an excellent testbed for the evaluation of K- and Ka-band mobile satellite communications systems. An overview of both of these terminals is presented in this paper.

  13. pH-sensitive Self-associations of the N-terminal Domain of NBCe1-A Suggest a Compact Conformation under Acidic Intracellular Conditions

    PubMed Central

    Gill, Harindarpal S

    2012-01-01

    NBCe1-A is an integral membrane protein that cotransports Na+ and HCO3- ions across the basolateral membrane of the proximal tubule. It is essential for maintaining a homeostatic balance of cellular and blood pH. In X-ray diffraction studies, we reported that the cytoplasmic, N-terminal domain of NBCe1-A (NtNBCe1-A) is a dimer. Here, biophysical measurements show that the dimer is in a concentration-dependent dynamic equilibrium among three additional states in solution that are characterized by its hydrodynamic properties, molar masses, emission spectra, binding properties, and stabilities as a function of pH. Under physiological conditions, dimers are in equilibrium with monomers that are pronounced at low concentration and clusters of molecular masses up to 3-5 times that of a dimer that are pronounced at high concentration. The equilibrium can be influenced so that individual dimers predominate in a taut conformation by lowering the pH. Conversely, dimers begin to relax and disassociate into an increasing population of monomers by elevating the pH. A mechanistic diagram for the inter-conversion of these states is given. The self-associations are further supported by surface plasmon resonance (SPR-Biacore) techniques that illustrate NtNBCe1-A molecules transiently bind with one another. Bicarbonate and bicarbonate-analog bisulfite appear to enhance dimerization and induce a small amount of tetramers. A model is proposed, where the Nt responds to pH or bicarbonate fluctuations inside the cell and plays a role in self-association of entire NBCe1-A molecules in the membrane. PMID:22316307

  14. c-Jun N-terminal kinase 1/c-Jun activation of the p53/microRNA 34a/sirtuin 1 pathway contributes to apoptosis induced by deoxycholic acid in rat liver.

    PubMed

    Ferreira, Duarte M S; Afonso, Marta B; Rodrigues, Pedro M; Simão, André L; Pereira, Diane M; Borralho, Pedro M; Rodrigues, Cecília M P; Castro, Rui E

    2014-03-01

    MicroRNAs (miRs) are increasingly associated with metabolic liver diseases. We have shown that ursodeoxycholic acid, a hydrophilic bile acid, counteracts the miR-34a/sirtuin 1 (SIRT1)/p53 pathway, activated in the liver of nonalcoholic steatohepatitis (NASH) patients. In contrast, hydrophobic bile acids, particularly deoxycholic acid (DCA), activate apoptosis and are increased in NASH. We evaluated whether DCA-induced apoptosis of rat hepatocytes occurs via miR-34a-dependent pathways and whether they connect with c-Jun N-terminal kinase (JNK) induction. DCA enhanced miR-34a/SIRT1/p53 proapoptotic signaling in a dose- and time-dependent manner. In turn, miR-34a inhibition and SIRT1 overexpression significantly rescued targeting of the miR-34a pathway and apoptosis by DCA. In addition, p53 overexpression activated the miR-34a/SIRT1/p53 pathway, further induced by DCA. DCA increased p53 expression as well as p53 transcriptional activation of PUMA and miR-34a itself, providing a functional mechanism for miR-34a activation. JNK1 and c-Jun were shown to be major targets of DCA, upstream of p53, in engaging the miR-34a pathway and apoptosis. Finally, activation of this JNK1/miR-34a proapoptotic circuit was also shown to occur in vivo in the rat liver. These results suggest that the JNK1/p53/miR-34a/SIRT1 pathway may represent an attractive pharmacological target for the development of new drugs to arrest metabolism- and apoptosis-related liver pathologies.

  15. Thermally Reactive Phenylethynyl-Terminated Bis (benzylester) and Bis (amide) Monomers Based on Semi-Enzymatically Produced 6-Phenylethynyl Picolinic Acid

    DTIC Science & Technology

    2005-12-01

    electron-withdrawing properties of the pyridine moiety would increase the reactivity of PEPCA in a Diels – Alder reaction if PEPCA were to serve as a...valid OMB control number. 1. REPORT DATE DEC 2005 2. REPORT TYPE 3. DATES COVERED 00-00-2005 to 00-00-2005 4. TITLE AND SUBTITLE Thermally...addition funnel, a condenser and nitrogen inlet and outlet were added 6-bromopicolinic acid (Aldrich; 2.02 g, 10 mmol) and methanol (50 mL). Thionyl

  16. SPT5, an essential gene important for normal transcription in Saccharomyces cerevisiae, encodes an acidic nuclear protein with a carboxy-terminal repeat.

    PubMed Central

    Swanson, M S; Malone, E A; Winston, F

    1991-01-01

    Mutations in the SPT5 gene of Saccharomyces cerevisiae were isolated previously as suppressors of delta insertion mutations at HIS4 and LYS2. In this study we have shown that spt5 mutations suppress the his4-912 delta and lys2-128 delta alleles by altering transcription. We cloned the SPT5 gene and found that either an increase or a decrease in the copy number of the wild-type SPT5 gene caused an Spt- phenotype. Construction and analysis of an spt5 null mutation demonstrated that SPT5 is essential for growth, suggesting that SPT5 may be required for normal transcription of a large number of genes. The SPT5 DNA sequence was determined; it predicted a 116-kDa protein with an extremely acidic amino terminus and a novel six-amino-acid repeat at the carboxy terminus (consensus = S-T/A-W-G-G-A/Q). By indirect immunofluorescence microscopy we showed that a bifunctional SPT5-beta-galactosidase protein was located in the yeast nucleus. This molecular analysis of the SPT5 gene revealed a number of interesting similarities to the previously characterized SPT6 gene of S. cerevisiae. These results suggest that SPT5 and SPT6 act in a related fashion to influence essential transcriptional processes in S. cerevisiae. Images PMID:1840633

  17. The C-terminal 18 Amino Acid Region of Dengue Virus NS5 Regulates its Subcellular Localization and Contains a Conserved Arginine Residue Essential for Infectious Virus Production

    PubMed Central

    Ng, Ivan H. W.; Chan, Kitti W. K.; Zhao, Yongqian; Ooi, Eng Eong; Lescar, Julien; Jans, David A.; Forwood, Jade K.

    2016-01-01

    Dengue virus NS5 is the most highly conserved amongst the viral non-structural proteins and is responsible for capping, methylation and replication of the flavivirus RNA genome. Interactions of NS5 with host proteins also modulate host immune responses. Although replication occurs in the cytoplasm, an unusual characteristic of DENV2 NS5 is that it localizes to the nucleus during infection with no clear role in replication or pathogenesis. We examined NS5 of DENV1 and 2, which exhibit the most prominent difference in nuclear localization, employing a combination of functional and structural analyses. Extensive gene swapping between DENV1 and 2 NS5 identified that the C-terminal 18 residues (Cter18) alone was sufficient to direct the protein to the cytoplasm or nucleus, respectively. The low micromolar binding affinity between NS5 Cter18 and the nuclear import receptor importin-alpha (Impα), allowed their molecular complex to be purified, crystallised and visualized at 2.2 Å resolution using x-ray crystallography. Structure-guided mutational analysis of this region in GFP-NS5 clones of DENV1 or 2 and in a DENV2 infectious clone reveal residues important for NS5 subcellular localization. Notably, the trans conformation adopted by Pro-884 allows proper presentation for binding Impα and mutating this proline to Thr, as present in DENV1 NS5, results in mislocalizaion of NS5 to the cytoplasm without compromising virus fitness. In contrast, a single mutation to alanine at NS5 position R888, a residue conserved in all flaviviruses, resulted in a completely non-viable virus, and the R888K mutation led to a severely attenuated phentoype, even though NS5 was located in the nucleus. R888 forms a hydrogen bond with Y838 that is also conserved in all flaviviruses. Our data suggests an evolutionarily conserved function for NS5 Cter18, possibly in RNA interactions that are critical for replication, that is independent of its role in subcellular localization. PMID:27622521

  18. Dormancy termination of western white pine (Pinus monticola Dougl. Ex D. Don) seeds is associated with changes in abscisic acid metabolism.

    PubMed

    Feurtado, J Allan; Ambrose, Stephen J; Cutler, Adrian J; Ross, Andrew R S; Abrams, Suzanne R; Kermode, Allison R

    2004-02-01

    Western white pine (Pinus monticola) seeds exhibit deep dormancy at maturity and seed populations require several months of moist chilling to reach their uppermost germination capacities. Abscisic acid (ABA) and its metabolites, phaseic acid (PA), dihydrophaseic acid (DPA), 7'-hydroxy ABA (7'OH ABA) and ABA-glucose ester (ABA-GE), were quantified in western white pine seeds during dormancy breakage (moist chilling) and germination using an HPLC-tandem mass spectrometry method with multiple reaction monitoring and internal standards incorporating deuterium-labeled analogs. In the seed coat, ABA and metabolite levels were high in dry seeds, but declined precipitously during the pre-moist-chilling water soak to relatively low levels thereafter. In the embryo and megagametophyte, ABA levels decreased significantly during moist chilling, coincident with an increase in the germination capacity of seeds. ABA catabolism occurred via several routes, depending on the stage and the seed tissue. Moist chilling of seeds led to increases in PA and DPA levels in both the embryo and megagametophyte. Within the embryo, 7'OH ABA and ABA-GE also accumulated during moist chilling; however, 7'OH ABA peaked early in germination. Changes in ABA flux, i.e. shifts in the ratio between biosynthesis and catabolism, occurred at three distinct stages during the transition from dormant seed to seedling. During moist chilling, the relative rate of ABA catabolism exceeded ABA biosynthesis. This trend became even more pronounced during germination, and germination was also accompanied by a decrease in the ABA catabolites DPA and PA, presumably as a result of their further metabolism and/or leaching/transport. The transition from germination to post-germinative growth was accompanied by a shift toward ABA biosynthesis. Dormant imbibed seeds, kept in warm moist conditions for 30 days (after an initial 13 days of soaking), maintained high ABA levels, while the amounts of PA, 7'OH ABA, and DPA

  19. Synthesis and characterization of carboxyl terminated poly(methacrylic acid) grafted chitosan/bentonite composite and its application for the recovery of uranium(VI) from aqueous media.

    PubMed

    Anirudhan, T S; Rijith, S

    2012-04-01

    A novel adsorbent poly(methacrylic acid)-grafted chitosan/bentonite (CTS-g-PMAA/Bent) composite was prepared through graft copolymerization reaction of methacrylic acid and chitosan in the presence of bentonite (Bent) and N,N'- methylenebisacrylamide as a crosslinker. The composite was well characterized using FTIR, XRD, XPS, SEM-EDS, surface area and zeta potential analyzers. The adsorption behavior of the composite toward uranium(VI) from aqueous media was studied under varying operating conditions of pH, concentration of U(VI), contact time, adsorbent dose and temperature. The optimum pH range for U(VI) adsorption was 5.5 at 30 °C. Concentration and temperature dependent rate constants were evaluated using pseudo-second-order kinetic model. The equilibrium data were correlated with the Langmuir isotherm model with an endothermic behavior. The equilibrium U(VI) sorption capacity was estimated to be 117.2 mg g(-1) at 30 °C. For the quantitative recovery of 100 mg L(-1) U(VI) from 1.0 L simulated nuclear industry wastewater, a minimum adsorbent dosage of 2.0 g CTS-g-PMAA/Bent was required. The calculated energy of activation (E(a) = 47.83 kJ/mol) was positively correlated with chemical adsorption process. The values of enthalpy, entropy and free energy of activation were calculated to explain the nature of adsorption process. Adsorption-desorption experiments over four cycles illustrate the feasibility of the repeated uses of this composite for the extraction of U(VI) from aqueous solutions.

  20. Inhibition of protein kinase C α/βII and activation of c-Jun NH2-terminal kinase mediate glycyrrhetinic acid induced apoptosis in non-small cell lung cancer NCI-H460 cells.

    PubMed

    Song, Junho; Ko, Hyun-suk; Sohn, Eun Jung; Kim, Bonglee; Kim, Jung Hyo; Kim, Hee Jeong; Kim, Chulwoo; Kim, Jai-eun; Kim, Sung-Hoon

    2014-02-15

    Though glycyrrhetinic acid (GA) from Glycyrrhiza glabra was known to exert antioxidant, antifilarial, hepatoprotective, anti-inflammatory and anti-tumor effects, the antitumor mechanism of GA was not clearly elucidated in non-small cell lung cancer cells (NSCLCCs). Thus, in the present study, the underlying apoptotic mechanism of GA was examined in NCI-H460 NSCLCCs. GA significantly suppressed the viability of NCI-H460 and A549 non-small lung cancer cells. Also, GA significantly increased the sub G1 population by cell cycle analysis and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) positive cells in a concentration dependent manner in NCI-H460 non-small lung cancer cells. Consistently, GA cleaved poly (ADP-ribosyl) polymerase (PARP), caspase 9/3, attenuated the expression of Bcl-XL, Bcl-2, Cyclin D1 and Cyclin E in NCI-H460 cells. Interestingly, GA attenuated the phosphorylation of protein kinase C (PKC) α/βII and extracellular activated protein kinase (ERK) as well as activated the phosphorylation of PKC δ and c-Jun NH2-terminal kinase in NCI-H460 cells. Conversely, PKC promoter phorbol 12-myristate 13-acetate (PMA) and JNK inhibitor SP600125 reversed the cleavages of caspase 3 and PARP induced by GA in NCI-H460 cells. Overall, our findings suggest that GA induces apoptosis via inhibition of PKC α/βII and activation of JNK in NCI-H460 non-small lung cancer cells as a potent anticancer candidate for lung cancer treatment.

  1. The C-Terminal Amino Acid of the MHC-I Heavy Chain Is Critical for Binding to Derlin-1 in Human Cytomegalovirus US11-Induced MHC-I Degradation

    PubMed Central

    Cho, Sunglim; Kim, Bo Young; Ahn, Kwangseog; Jun, Youngsoo

    2013-01-01

    Derlin-1 plays a critical role in endoplasmic reticulum-associated protein degradation (ERAD) of a particular subset of proteins. Although it is generally accepted that Derlin-1 mediates the export of ERAD substrates from the ER to the cytosol, little is known about how Derlin-1 interacts with these substrates. Human cytomegalovirus (HCMV) US11 exploits Derlin-1-dependent ERAD to degrade major histocompatibility complex class I (MHC-I) molecules and evade immune surveillance. US11 requires the cytosolic tail of the MHC-I heavy chain to divert MHC-I molecules into the ERAD pathway for degradation; however, the underlying mechanisms remain unknown. Here, we show that the cytosolic tail of the MHC-I heavy chain, although not required for interaction with US11, is required for tight binding to Derlin-1 and thus for US11-induced dislocation of the MHC-I heavy chain to the cytosol for proteasomal degradation. Surprisingly, deletion of a single C-terminal amino acid from the cytosolic tail disrupted the interaction between MHC-I molecules and Derlin-1, rendering mutant MHC-I molecules resistant to US11-induced degradation. Consistently, deleting the C-terminal cytosolic region of Derlin-1 prevented it from binding to MHC-I molecules. Taken together, these results suggest that the cytosolic region of Derlin-1 is involved in ERAD substrate binding and that this interaction is critical for the Derlin-1-mediated dislocation of the MHC-I heavy chain to the cytosol during US11-induced MHC-I degradation. PMID:23951315

  2. Abrogation of TLR3 inhibition by discrete amino acid changes in the C-terminal half of the West Nile virus NS1 protein.

    PubMed

    Morrison, Clayton R; Scholle, Frank

    2014-05-01

    West Nile virus (WNV) is a mosquito-transmitted pathogen, which causes significant disease in humans. The innate immune system is a first-line defense against invading microorganism and many flaviviruses, including WNV, have evolved multifunctional proteins, which actively suppress its activation and antiviral actions. The WNV non-structural protein 1 (NS1) inhibits signal transduction originating from Toll-like receptor 3 (TLR3) and also critically contributes to virus genome replication. In this study we developed a novel FACS-based screen to attempt to separate these two functions. The individual amino acid changes P320S and M333V in NS1 restored TLR3 signaling in virus-infected HeLa cells. However, virus replication was also attenuated, suggesting that the two functions are not easily separated and may be contained within overlapping domains. The residues we identified are completely conserved among several mosquito- and tick-borne flaviviruses, indicating that they are of biological importance to the virus.

  3. Terminal automation system maintenance

    SciTech Connect

    Coffelt, D.; Hewitt, J.

    1997-01-01

    Nothing has improved petroleum product loading in recent years more than terminal automation systems. The presence of terminal automation systems (TAS) at loading racks has increased operational efficiency and safety and enhanced their accounting and management capabilities. However, like all finite systems, they occasionally malfunction or fail. Proper servicing and maintenance can minimize this. And in the unlikely event a TAS breakdown does occur, prompt and effective troubleshooting can reduce its impact on terminal productivity. To accommodate around-the-clock loading at racks, increasingly unattended by terminal personnel, TAS maintenance, servicing and troubleshooting has become increasingly demanding. It has also become increasingly important. After 15 years of trial and error at petroleum and petrochemical storage and transfer terminals, a number of successful troubleshooting programs have been developed. These include 24-hour {open_quotes}help hotlines,{close_quotes} internal (terminal company) and external (supplier) support staff, and {open_quotes}layered{close_quotes} support. These programs are described.

  4. Dynamic in-plane potential gradients for actively controlling electrochemical reactions: Part I. Characterization of 1- and 2-component alkanethiol monolayer gradients on thin gold films. Part II. Applications of in-plane potential gradients

    NASA Astrophysics Data System (ADS)

    Balss, Karin Maria

    The research contained in this thesis is focused on the formation and characterization of surface composition gradients on thin gold films that are formed by applications of in-plane potential gradients. Injecting milliamp currents into thin Au films yields significant in-plane voltage drops so that, rather than assuming a single value of potential, an in-plane potential gradient is imposed on the film which depends on the resistivity of the film, the cross sectional area and the magnitude of the potential drop. Furthermore, the in-plane electric potential gradient means that, relative to a solution reference couple, electrochemical reactions occurs at defined spatial positions corresponding to the local potential, V(x) ˜ E0. The spatial gradient in electrochemical potential can then produce spatially dependent electrochemistry. Surface-chemical potential gradients can be prepared by arranging the spread of potentials to span an electrochemical wave mediating redox-associated adsorption or desorption. Examples of reactions that can be spatially patterned include the electrosorption of alkanethiols and over-potential metal deposition. The unique advantage of this method for patterning spatial compositions is the control of surface coverage in both space and time. The thesis is organized into two parts. In Part I, formation and characterization of 1- and 2-component alkanethiol monolayer gradients is investigated. Numerous surface science tools are employed to examine the distribution in coverage obtained by application of in-plane potential gradients. Macroscopic characterization was obtained by sessile water drop contact angle measurements and surface plasmon resonance imaging. Gradients were also imaged on micron length scales with pulsed-force mode atomic force microscopy. Direct chemical evidence of surface compositions in aromatic thiol surface coverage was obtained by surface-enhanced Raman spectroscopy. In Part II, the applications of in-plane potential

  5. Extended Gate Field-Effect Transistor Biosensors for Point-Of-Care Testing of Uric Acid.

    PubMed

    Guan, Weihua; Reed, Mark A

    2017-01-01

    An enzyme-free redox potential sensor using off-chip extended-gate field effect transistor (EGFET) with a ferrocenyl-alkanethiol modified gold electrode has been used to quantify uric acid concentration in human serum and urine. Hexacyanoferrate (II) and (III) ions are used as redox reagent. The potentiometric sensor measures the interface potential on the ferrocene immobilized gold electrode, which is modulated by the redox reaction between uric acid and hexacyanoferrate ions. The device shows a near Nernstian response to uric acid and is highly specific to uric acid in human serum and urine. The interference that comes from glucose, bilirubin, ascorbic acid, and hemoglobin is negligible in the normal concentration range of these interferents. The sensor also exhibits excellent long term reliability and is regenerative. This extended gate field effect transistor based sensor is promising for point-of-care detection of uric acid due to the small size, low cost, and low sample volume consumption.

  6. C-Terminal Amino Acids 471-507 of Avian Hepatitis E Virus Capsid Protein Are Crucial for Binding to Avian and Human Cells.

    PubMed

    Zhang, Xinquan; Bilic, Ivana; Marek, Ana; Glösmann, Martin; Hess, Michael

    2016-01-01

    The infection of chickens with avian Hepatitis E virus (avian HEV) can be asymptomatic or induces clinical signs characterized by increased mortality and decreased egg production in adult birds. Due to the lack of an efficient cell culture system for avian HEV, the interaction between virus and host cells is still barely understood. In this study, four truncated avian HEV capsid proteins (ORF2-1 - ORF2-4) with an identical 338aa deletion at the N-terminus and gradual deletions from 0, 42, 99 and 136aa at the C-terminus, respectively, were expressed and used to map the possible binding site within avian HEV capsid protein. Results from the binding assay showed that three truncated capsid proteins attached to avian LMH cells, but did not penetrate into cells. However, the shortest construct, ORF2-4, lost the capability of binding to cells suggesting that the presence of amino acids 471 to 507 of the capsid protein is crucial for the attachment. The construct ORF2-3 (aa339-507) was used to study the potential binding of avian HEV capsid protein to human and other avian species. It could be demonstrated that ORF2-3 was capable of binding to QT-35 cells from Japanese quail and human HepG2 cells but failed to bind to P815 cells. Additionally, chicken serum raised against ORF2-3 successfully blocked the binding to LMH cells. Treatment with heparin sodium salt or sodium chlorate significantly reduced binding of ORF2-3 to LMH cells. However, heparinase II treatment of LMH cells had no effect on binding of the ORF2-3 construct, suggesting a possible distinct attachment mechanism of avian as compared to human HEV. For the first time, interactions between avian HEV capsid protein and host cells were investigated demonstrating that aa471 to 507 of the capsid protein are needed to facilitate interaction with different kind of cells from different species.

  7. C-Terminal Amino Acids 471-507 of Avian Hepatitis E Virus Capsid Protein Are Crucial for Binding to Avian and Human Cells

    PubMed Central

    Zhang, Xinquan; Bilic, Ivana; Marek, Ana; Glösmann, Martin; Hess, Michael

    2016-01-01

    The infection of chickens with avian Hepatitis E virus (avian HEV) can be asymptomatic or induces clinical signs characterized by increased mortality and decreased egg production in adult birds. Due to the lack of an efficient cell culture system for avian HEV, the interaction between virus and host cells is still barely understood. In this study, four truncated avian HEV capsid proteins (ORF2-1 – ORF2-4) with an identical 338aa deletion at the N-terminus and gradual deletions from 0, 42, 99 and 136aa at the C-terminus, respectively, were expressed and used to map the possible binding site within avian HEV capsid protein. Results from the binding assay showed that three truncated capsid proteins attached to avian LMH cells, but did not penetrate into cells. However, the shortest construct, ORF2-4, lost the capability of binding to cells suggesting that the presence of amino acids 471 to 507 of the capsid protein is crucial for the attachment. The construct ORF2-3 (aa339-507) was used to study the potential binding of avian HEV capsid protein to human and other avian species. It could be demonstrated that ORF2-3 was capable of binding to QT-35 cells from Japanese quail and human HepG2 cells but failed to bind to P815 cells. Additionally, chicken serum raised against ORF2-3 successfully blocked the binding to LMH cells. Treatment with heparin sodium salt or sodium chlorate significantly reduced binding of ORF2-3 to LMH cells. However, heparinase II treatment of LMH cells had no effect on binding of the ORF2-3 construct, suggesting a possible distinct attachment mechanism of avian as compared to human HEV. For the first time, interactions between avian HEV capsid protein and host cells were investigated demonstrating that aa471 to 507 of the capsid protein are needed to facilitate interaction with different kind of cells from different species. PMID:27073893

  8. The C-terminal 50 Amino Acid Residues of Dengue NS3 Protein Are Important for NS3-NS5 Interaction and Viral Replication*

    PubMed Central

    Tay, Moon Y. F.; Saw, Wuan Geok; Zhao, Yongqian; Chan, Kitti W. K.; Singh, Daljit; Chong, Yuwen; Forwood, Jade K.; Ooi, Eng Eong; Grüber, Gerhard; Lescar, Julien; Luo, Dahai; Vasudevan, Subhash G.

    2015-01-01

    Dengue virus multifunctional proteins NS3 protease/helicase and NS5 methyltransferase/RNA-dependent RNA polymerase form part of the viral replication complex and are involved in viral RNA genome synthesis, methylation of the 5′-cap of viral genome, and polyprotein processing among other activities. Previous studies have shown that NS5 residue Lys-330 is required for interaction between NS3 and NS5. Here, we show by competitive NS3-NS5 interaction ELISA that the NS3 peptide spanning residues 566–585 disrupts NS3-NS5 interaction but not the null-peptide bearing the N570A mutation. Small angle x-ray scattering study on NS3(172–618) helicase and covalently linked NS3(172–618)-NS5(320–341) reveals a rigid and compact formation of the latter, indicating that peptide NS5(320–341) engages in specific and discrete interaction with NS3. Significantly, NS3:Asn-570 to alanine mutation introduced into an infectious DENV2 cDNA clone did not yield detectable virus by plaque assay even though intracellular double-stranded RNA was detected by immunofluorescence. Detection of increased negative-strand RNA synthesis by real time RT-PCR for the NS3:N570A mutant suggests that NS3-NS5 interaction plays an important role in the balanced synthesis of positive- and negative-strand RNA for robust viral replication. Dengue virus infection has become a global concern, and the lack of safe vaccines or antiviral treatments urgently needs to be addressed. NS3 and NS5 are highly conserved among the four serotypes, and the protein sequence around the pinpointed amino acids from the NS3 and NS5 regions are also conserved. The identification of the functionally essential interaction between the two proteins by biochemical and reverse genetics methods paves the way for rational drug design efforts to inhibit viral RNA synthesis. PMID:25488659

  9. Superconducting Cable Termination

    DOEpatents

    Sinha, Uday K.; Tolbert, Jerry

    2005-08-30

    Disclosed is a termination that connects high temperature superconducting (HTS) cable immersed in pressurized liquid nitrogen to high voltage and neutral (shield) external bushings at ambient temperature and pressure. The termination consists of a splice between the HTS power (inner) and shield (outer) conductors and concentric copper pipes which are the conductors in the termination. There is also a transition from the dielectric tape insulator used in the HTS cable to the insulators used between and around the copper pipe conductors in the termination. At the warm end of the termination the copper pipes are connected via copper braided straps to the conventional warm external bushings which have low thermal stresses. This termination allows for a natural temperature gradient in the copper pipe conductors inside the termination which enables the controlled flashing of the pressurized liquid coolant (nitrogen) to the gaseous state. Thus the entire termination is near the coolant supply pressure and the high voltage and shield cold bushings, a highly stressed component used in most HTS cables, are eliminated. A sliding seal allows for cable contraction as it is cooled from room temperature to ˜72-82 K. Seals, static vacuum, and multi-layer superinsulation minimize radial heat leak to the environment.

  10. β-Amyloid Oligomers Induce Phosphorylation of Tau and Inactivation of Insulin Receptor Substrate via c-Jun N-Terminal Kinase Signaling: Suppression by Omega-3 Fatty Acids and Curcumin

    PubMed Central

    Ma, Qiu-Lan; Yang, Fusheng; Rosario, Emily R.; Ubeda, Oliver J.; Beech, Walter; Gant, Dana J.; Chen, Ping Ping; Hudspeth, Beverly; Chen, Cory; Zhao, Yongle; Vinters, Harry V.; Frautschy, Sally A.

    2009-01-01

    Both insulin resistance (type II diabetes) and β-amyloid (Aβ) oligomers are implicated in Alzheimer's disease (AD). Here, we investigate the role of Aβ oligomer-induced c-Jun N-terminal kinase (JNK) activation leading to phosphorylation and degradation of the adaptor protein insulin receptor substrate-1 (IRS-1). IRS-1 couples insulin and other trophic factor receptors to downstream kinases and neuroprotective signaling. Increased phospho-IRS-1 is found in AD brain and insulin-resistant tissues from diabetics. Here, we report Aβ oligomers significantly increased active JNK and phosphorylation of IRS-1 (Ser616) and tau (Ser422) in cultured hippocampal neurons, whereas JNK inhibition blocked these responses. The omega-3 fatty acid docosahexaenoic acid (DHA) similarly inhibited JNK and the phosphorylation of IRS-1 and tau in cultured hippocampal neurons. Feeding 3xTg-AD transgenic mice a diet high in saturated and omega-6 fat increased active JNK and phosphorylated IRS-1 and tau. Treatment of the 3xTg-AD mice on high-fat diet with fish oil or curcumin or a combination of both for 4 months reduced phosphorylated JNK, IRS-1, and tau and prevented the degradation of total IRS-1. This was accompanied by improvement in Y-maze performance. Mice fed with fish oil and curcumin for 1 month had more significant effects on Y-maze, and the combination showed more significant inhibition of JNK, IRS-1, and tau phosphorylation. These data indicate JNK mediates Aβ oligomer inactivation of IRS-1 and phospho-tau pathology and that dietary treatment with fish oil/DHA, curcumin, or a combination of both has the potential to improve insulin/trophic signaling and cognitive deficits in AD. PMID:19605645

  11. Characterization of the wild type and truncated form of a neutral GH10 xylanase from Coprinus cinereus: Roles of C-terminal basic amino acid-rich extension in its SDS resistance, thermostability and activity.

    PubMed

    Hu, Hang; Chen, Kaixiang; Li, Lulu; Long, Liangkun; Ding, Shaojun

    2017-02-07

    A neutral xylanase (Ccxyn) was identified from Coprinus cinereus. It has a single GH10 catalytic domain with a basic amino acid-rich extension (PVRRK) at C-terminus. In this study, the wild-type (Ccxyn) and C-terminus truncated xylanase (CcXynΔ5C) were heterologously expressed in Pichia pastoris and their characteristics were comparatively analyzed with aims to examine the effect of this extension on the enzyme function. The circular dichorism (CD) analysis indicated that both enzymes in general had a similar structure, but CcXynΔ5C contained less α-helices (42.9%) and more random coil contents (35.5%) than CcXyn (47.0% and 32.8%, respectively). Both enzymes had same pH (7.0) and temperature (45°C) optima, and similar substrate specificity on different xylans. They all hydrolyzed beechwood xylan primarily to xylobiose and xylotriose. The amounts of xylobiose and xylotriose account for 91.5% and 92.2 % (w/w) of total xylooligosaccharides (XOS) generated from beechwood by Ccxyn and CcxynΔ5C, respectively. However, truncation of C-terminal 5-amino acids extension significantly improves its thermostability, SDS resistance and pH stability at pH 6.0-9.0. Furthermore, CcxynΔ5C exhibited much lower Km value than Ccxyn (0.27 mg ml⁻¹ vs 0.83 mg ml⁻¹), therefore, the catalytic efficiency of CcXynΔ5C was 2.4 times higher than that of CcXyn. These properties make CcxynΔ5C a good model for the structure-function study of (α/β)₈-barrel folded enzyme and a promising candidate for various applications, especially in the detergent industry and XOS production.

  12. The reaction of iodine and thiol-blocking reagents with human complement components C2 and factor B. Purification and N-terminal amino acid sequence of a peptide from C2a containing a free thiol group.

    PubMed Central

    Parkes, C; Gagnon, J; Kerr, M A

    1983-01-01

    Human complement components C2 and Factor B each contain one free thiol group/molecule. Reaction with p-chloromercuribenzoate destroyed the haemolytic activity of C2 but had no effect on Factor B. Reaction of C2 with I2 gave a 16-fold enhancement of its haemolytic activity. The pH optimum for the reaction was 7.0. The I2 reacted at the thiol group in C2 with a stoicheiometry of 1 mol of I2/mol of C2. The product of the reaction was unaffected by millimolar concentrations of dithiothreitol; however, azide and cyanide were inhibitory. Reaction with azide did not result in re-expression of the thiol group. Mild oxidation of the thiol group with m-chloroperbenzoic acid did not enhance the haemolytic activity. The results suggest that reaction with I2 causes intramolecular covalent, but not disulphide, bond formation. I2 reacted with Factor B at the free thiol group without affecting the haemolytic activity. A CNBr-cleavage peptide from C2a (obtained by cleavage of C2 by subcomponent C1s) containing the free thiol group was isolated. Automated Edman degradation of the peptide showed that it was the N-terminal peptide of C2a. The free thiol group was identified at position 18. PMID:6555044

  13. Molecular cloning of human terminal deoxynucleotidyltransferase.

    PubMed Central

    Peterson, R C; Cheung, L C; Mattaliano, R J; Chang, L M; Bollum, F J

    1984-01-01

    A cDNA of the human terminal deoxynucleotidyltransferase (TdT; "terminal transferase," EC 2.7.7.31) was isolated from a human lymphoblastoid cell cDNA library in lambda gt 11 by using immunological procedures. Four inserts containing 723 to 939 base pairs were recloned in pBR322 for hybridization and preliminary sequence studies. mRNA selected by hybridization to recombinant DNA was translated to a 58-kDa peptide that specifically immunoprecipitated with rabbit antibodies to calf terminal transferase and mouse monoclonal antibody to human terminal transferase. Blot hybridization of total poly(A)+ RNA from KM3 (TdT+) cells with nick-translated pBR322 recombinant DNA detected a message of about 2000 nucleotides, sufficient to code for the 580 amino acids in the protein. mRNA from terminal transferase- cells gave no signal in hybrid selection or RNA blot hybridization. The complete sequence of the 939-base-pair insert sequence was obtained from deletions cloned in pUC8. The DNA sequence contains an open reading frame coding for 238 amino acids, about 40% of the protein. Three peptides isolated by HPLC from tryptic digests of succinylated 58-kDa calf thymus terminal transferase were sequenced, providing 20, 18, and 22 residues of peptide sequence. A search of the translated sequence of the 939-base-pair insert shows three regions beginning after arginine that have greater than 90% homology with the sequence determined from the calf thymus terminal transferase peptides. These results provide unambiguous evidence that the human terminal transferase sequence has been cloned. Images PMID:6087320

  14. Flight Termination Criteria

    NASA Astrophysics Data System (ADS)

    Haber, Jerold M.; Larson, Erik

    2013-09-01

    The first line of defense in protecting the public against the threat of injury from a failing space booster is the flight termination system. Consequently, these systems must be highly reliable and the criteria for flight termination must be carefully formulated. Criteria must be developed based on observable data that allows adequate time for the data to be assessed and a flight termination action to be triggered. Criteria should be set so that 1) the chance a good vehicle will be terminated is small, 2) the chance of failing to terminate an errant vehicle before it can hazard population centers or valuable assets is minimal, and 3) there is assurance that the combination of the planned trajectory and mission rules do not induce excessive risks to land based populations, air lanes, and shipping lanes should the vehicle need to be terminated [1].This paper provides an overview of the approaches to developing and implement flight termination criteria and a tool for understanding risk implications of proposed criteria.

  15. Nonleaking battery terminals

    NASA Technical Reports Server (NTRS)

    Snider, W. E.; Nagle, W. J.

    1972-01-01

    Three different terminals were designed for usage in a 40 ampere/hour silver zinc battery which has a 45 percent KOH by weight electrolyte in a plastic battery case. Life tests, including thermal cycling, electrical charge and discharge for up to three years duration, were conducted on these three different terminal designs. Tests for creep rate and tensile strength were conducted on the polyphenylene oxide (PPO) plastic battery cases. Some cases were unused and others containing KOH electrolyte were placed on life tests. The design and testing of nonleaking battery terminals for use with a potassium hydroxide (KOH) electrolyte in a plastic case are discussed.

  16. Nonleaking battery terminals.

    NASA Technical Reports Server (NTRS)

    Snider, W. E.; Nagle, W. J.

    1972-01-01

    Three different terminals were designed for usage in a 40 ampere/hour silver zinc battery which has a 45% KOH by weight electrolyte in a plastic battery case. Life tests, including thermal cycling, electrical charge and discharge for up to three years duration, were conducted on these three different terminal designs. Tests for creep rate and tensile strength were conducted on the polyphenylene oxide plastic battery cases. Some cases were unused and others containing KOH electrolyte were placed on life tests. The design and testing of nonleaking battery terminals for use with a KOH electrolyte in a plastic case are considered.

  17. Intimacy and terminal care

    PubMed Central

    Gilley, Judy

    1988-01-01

    Four cases are summarized in which the general practitioner is involved in the terminal care of one partner of a stable marital relationship. The need to conceptualize the expectations of the patient, the family and the doctor in terminal care is stressed. An attempt is made to illustrate how the quality of the pre-existing sexual relationship, the dying person's own sexuality, and ultimately the capacity for physical expression of intimacy in the marriage profoundly influence choices in terminal care and the quality of dying. PMID:3204583

  18. Experimental and theoretical study of CO collisions with CH3- and CF3-terminated self-assembled monolayers

    NASA Astrophysics Data System (ADS)

    Alexander, William A.; Morris, John R.; Troya, Diego

    2009-02-01

    We present an experimental and theoretical study of the dynamics of collisions of the CO molecule with organic surfaces. Experimentally, we scatter CO at 60 kJ mol-1 and 30° incident angle from regular (CH3-terminated) and ω-fluorinated (CF3-terminated) alkanethiol self-assembled monolayers (SAMs) and measure the time-of-flight distributions at the specular angle after collision. At a theoretical level, we carry out classical-trajectory simulations of the same scattering process using CO/SAM potential-energy surfaces derived from ab initio calculations. Agreement between measured and calculated final translational energy distributions justifies use of the calculations to examine dynamical behavior of the gas/surface system not available directly from the experiment. Calculated state-to-state energy-transfer properties indicate that the collisions are notably vibrationally adiabatic. Similarly, translational energy transfer from and to CO rotation is relatively weak. These trends are examined as a function of collision energy and incident angle to provide a deeper understanding of the factors governing state-to-state energy transfer in gas/organic-surface collisions.

  19. Nontraumatic terminal ileal perforation

    PubMed Central

    Wani, Rauf A; Parray, Fazl Q; Bhat, Nadeem A; Wani, Mehmood A; Bhat, Tasaduq H; Farzana, Fowzia

    2006-01-01

    Background There is still confusion and controversy over the diagnosis and optimal surgical treatment of non traumatic terminal ileal perforation-a cause of obscure peritonitis. Methods This study was a prospective study aimed at evaluating the clinical profile, etiology and optimal surgical management of patients with nontraumatic terminal ileal perforation. Results There were 79 cases of nontraumatic terminal ileal perforation; the causes for perforation were enteric fever(62%), nonspecific inflammation(26%), obstruction(6%), tuberculosis(4%) and radiation enteritis (1%). Simple closure of the perforation (49%) and end to side ileotransverse anastomosis(42%) were the mainstay of the surgical management. Conclusion Terminal ileal perforation should be suspected in all cases of peritonitis especially in developing countries and surgical treatment should be optimized taking various accounts like etiology, delay in surgery and operative findings into consideration to reduce the incidence of deadly complications like fecal fistula. PMID:16759405

  20. Ability of Serum Glial Fibrillary Acidic Protein, Ubiquitin C-Terminal Hydrolase-L1, and S100B To Differentiate Normal and Abnormal Head Computed Tomography Findings in Patients with Suspected Mild or Moderate Traumatic Brain Injury.

    PubMed

    Welch, Robert D; Ayaz, Syed I; Lewis, Lawrence M; Unden, Johan; Chen, James Y; Mika, Valerie H; Saville, Ben; Tyndall, Joseph A; Nash, Marshall; Buki, Andras; Barzo, Pal; Hack, Dallas; Tortella, Frank C; Schmid, Kara; Hayes, Ronald L; Vossough, Arastoo; Sweriduk, Stephen T; Bazarian, Jeffrey J

    2016-01-15

    Head computed tomography (CT) imaging is still a commonly obtained diagnostic test for patients with minor head injury despite availability of clinical decision rules to guide imaging use and recommendations to reduce radiation exposure resulting from unnecessary imaging. This prospective multicenter observational study of 251 patients with suspected mild to moderate traumatic brain injury (TBI) evaluated three serum biomarkers' (glial fibrillary acidic protein [GFAP], ubiquitin C-terminal hydrolase-L1 [UCH-L1] and S100B measured within 6 h of injury) ability to differentiate CT negative and CT positive findings. Of the 251 patients, 60.2% were male and 225 (89.6%) had a presenting Glasgow Coma Scale score of 15. A positive head CT (intracranial injury) was found in 36 (14.3%). UCH-L1 was 100% sensitive and 39% specific at a cutoff value >40 pg/mL. To retain 100% sensitivity, GFAP was 0% specific (cutoff value 0 pg/mL) and S100B had a specificity of only 2% (cutoff value 30 pg/mL). All three biomarkers had similar values for areas under the receiver operator characteristic curve: 0.79 (95% confidence interval; 0.70-0.88) for GFAP, 0.80 (0.71-0.89) for UCH-L1, and 0.75 (0.65-0.85) for S100B. Neither GFAP nor UCH-L1 curve values differed significantly from S100B (p = 0.21 and p = 0.77, respectively). In our patient cohort, UCH-L1 outperformed GFAP and S100B when the goal was to reduce CT use without sacrificing sensitivity. UCH-L1 values <40 pg/mL could potentially have aided in eliminating 83 of the 215 negative CT scans. These results require replication in other studies before the test is used in actual clinical practice.

  1. 29 CFR 4043.24 - Termination or partial termination.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Secretary of the Treasury determines that there has been a termination or partial termination of a plan... 29 Labor 9 2010-07-01 2010-07-01 false Termination or partial termination. 4043.24 Section 4043.24 Labor Regulations Relating to Labor (Continued) PENSION BENEFIT GUARANTY CORPORATION PLAN...

  2. The last glacial termination.

    PubMed

    Denton, G H; Anderson, R F; Toggweiler, J R; Edwards, R L; Schaefer, J M; Putnam, A E

    2010-06-25

    A major puzzle of paleoclimatology is why, after a long interval of cooling climate, each late Quaternary ice age ended with a relatively short warming leg called a termination. We here offer a comprehensive hypothesis of how Earth emerged from the last global ice age. A prerequisite was the growth of very large Northern Hemisphere ice sheets, whose subsequent collapse created stadial conditions that disrupted global patterns of ocean and atmospheric circulation. The Southern Hemisphere westerlies shifted poleward during each northern stadial, producing pulses of ocean upwelling and warming that together accounted for much of the termination in the Southern Ocean and Antarctica. Rising atmospheric CO2 during southern upwelling pulses augmented warming during the last termination in both polar hemispheres.

  3. Phenylethynyl terminated reactive oligomer

    NASA Technical Reports Server (NTRS)

    Bryant, Robert G. (Inventor); Jensen, Brian J. (Inventor); Hergenrother, Paul M. (Inventor)

    1995-01-01

    A composition of matter having the general structure: ##STR1## (wherein X is F, Cl, or NO.sub.2, and Y is CO, SO.sub.2 or C(CF.sub.3).sub.2) is employed to terminate a nucleophilic reagent, resulting in the exclusive production of phenylethynyl terminated reactive oligomers which display unique thermal characteristics. A reactive diluent having the general structure: ##STR2## (wherein R is any aliphatic or aromatic moiety) is employed to decrease the melt viscosity of a phenylethynyl terminated reactive oligomer and to subsequently react therewith to provide a thermosetting material of enhanced density. These materials have features which make them attractive candidates for use as composite matrices and adhesives.

  4. Comparison of chemoreceptions of terminal buds and pit organs of the carp, Cyprinus carpio L.

    PubMed

    Marui, T; Funakoshi, M

    1980-07-14

    Neural responses to several chemicals of the pit organs and terminal buds on the facial skin of the carp were compared electrophysiologically. Nerve inpulses from the pit organs were larger than those from the terminal buds. The pit organs were more sensitive to salts and especially acids than the terminal buds. The former did not respond to sucrose, silk worm pupa extract, betaine and amino acids except acidic ones. The latter, however, responded well to them.

  5. ALSEP termination report

    NASA Technical Reports Server (NTRS)

    Bates, J. R.; Lauderdale, W. W.; Kernaghan, H.

    1979-01-01

    The Apollo Lunar Surface Experiments Package (ALSEP) final report was prepared when support operations were terminated September 30, 1977, and NASA discontinued the receiving and processing of scientific data transmitted from equipment deployed on the lunar surface. The ALSEP experiments (Apollo 11 to Apollo 17) are described and pertinent operational history is given for each experiment. The ALSEP data processing and distribution are described together with an extensive discussion on archiving. Engineering closeout tests and results are given, and the status and configuration of the experiments at termination are documented. Significant science findings are summarized by selected investigators. Significant operational data and recommendations are also included.

  6. Electrical termination techniques

    NASA Technical Reports Server (NTRS)

    Oakey, W. E.; Schleicher, R. R.

    1976-01-01

    A technical review of high reliability electrical terminations for electronic equipment was made. Seven techniques were selected from this review for further investigation, experimental work, and preliminary testing. From the preliminary test results, four techniques were selected for final testing and evaluation. These four were: (1) induction soldering, (2) wire wrap, (3) percussive arc welding, and (4) resistance welding. Of these four, induction soldering was selected as the best technique in terms of minimizing operator errors, controlling temperature and time, minimizing joint contamination, and ultimately producing a reliable, uniform, and reusable electrical termination.

  7. Automated carboxy-terminal sequence analysis of peptides.

    PubMed Central

    Bailey, J. M.; Shenoy, N. R.; Ronk, M.; Shively, J. E.

    1992-01-01

    Proteins and peptides can be sequenced from the carboxy-terminus with isothiocyanate reagents to produce amino acid thiohydantoin derivatives. Previous studies in our laboratory have focused on solution phase conditions for formation of the peptidylthiohydantoins with trimethylsilylisothiocyanate (TMS-ITC) and for hydrolysis of these peptidylthiohydantoins into an amino acid thiohydantoin derivative and a new shortened peptide capable of continued degradation (Bailey, J. M. & Shively, J. E., 1990, Biochemistry 29, 3145-3156). The current study is a continuation of this work and describes the construction of an instrument for automated C-terminal sequencing, the application of the thiocyanate chemistry to peptides covalently coupled to a novel polyethylene solid support (Shenoy, N. R., Bailey, J. M., & Shively, J. E., 1992, Protein Sci. I, 58-67), the use of sodium trimethylsilanolate as a novel reagent for the specific cleavage of the derivatized C-terminal amino acid, and the development of methodology to sequence through the difficult amino acid, aspartate. Automated programs are described for the C-terminal sequencing of peptides covalently attached to carboxylic acid-modified polyethylene. The chemistry involves activation with acetic anhydride, derivatization with TMS-ITC, and cleavage of the derivatized C-terminal amino acid with sodium trimethylsilanolate. The thiohydantoin amino acid is identified by on-line high performance liquid chromatography using a Phenomenex Ultracarb 5 ODS(30) column and a triethylamine/phosphoric acid buffer system containing pentanesulfonic acid. The generality of our automated C-terminal sequencing methodology was examined by sequencing model peptides containing all 20 of the common amino acids. All of the amino acids were found to sequence in high yield (90% or greater) except for asparagine and aspartate, which could be only partially removed, and proline, which was found not be capable of derivatization. In spite of these

  8. Prematurely terminated slug tests

    SciTech Connect

    Karasaki, K. )

    1990-07-01

    A solution of the well response to a prematurely terminated slug test (PTST) is presented. The advantages of a PTST over conventional slug tests are discussed. A systematized procedure of a PTST is proposed, where a slug test is terminated in the midpoint of the flow point, and the subsequent shut-in data is recorded and analyzed. This method requires a downhole shut-in device and a pressure transducer, which is no more than the conventional deep-well slug testing. As opposed to slug tests, which are ineffective when a skin is present, more accurate estimate of formation permeability can be made using a PTST. Premature termination also shortens the test duration considerably. Because in most cases no more information is gained by completing a slug test to the end, the author recommends that conventional slug tests be replaced by the premature termination technique. This study is part of an investigation of the feasibility of geologic isolation of nuclear wastes being carried out by the US Department of Energy and the National Cooperative for the Storage of Radioactive Waste of Switzerland.

  9. Navy Multiband Terminal (NMT)

    DTIC Science & Technology

    2015-12-01

    Selected Acquisition Report (SAR) RCS: DD-A&T(Q&A)823-290 Navy Multiband Terminal (NMT) As of FY 2017 President’s Budget Defense Acquisition...Research, Development, Test, and Evaluation SAR - Selected Acquisition Report SCP - Service Cost Position TBD - To Be Determined TY - Then Year UCR

  10. Trauma and termination.

    PubMed

    Ferraro, F

    1995-02-01

    The author suggests a particular reading of the thesis put forward by Freud in 'Analysis terminable and interminable' that an effective and more definitive conclusion may be expected in analyses of cases with traumatic aetiology. This reading shifts the emphasis from the patient's history to the possibility of its crystallising in focal nuclei emerging within the analytic relationship under the pressure of the termination. The revival of separation anxieties which cannot be worked through, and their crystallisation in precipitating traumatic events, may give rise to decisive psychic work allowing the analysis to be brought to a conclusion. Two case histories are presented to show how the end of the analysis assumes the form of a new trauma, which reactivates in the present, traumatic anxieties from the patient's own infantile history. In the first case a premature birth and in the second a miscarriage, originally experienced as isolated automatic events without time or history, are relived in the terminal phase as vicissitudes of the transference, so that new meaning can be assigned to them and they can be withdrawn from the somatic cycle of repetition. The powerful tendency to act out and the intense countertransference pressure on the analyst are discussed in the light of the specificities of this phase, which is crucial to the success of the analysis. This leads to a re-examination, in the concluding notes, of some theoretical questions inherent in the problem of the termination and, in particular, to a discussion of the ambiguous concept of a natural ending.

  11. Modeling Terminal Velocity

    ERIC Educational Resources Information Center

    Brand, Neal; Quintanilla, John A.

    2013-01-01

    Using a simultaneously falling softball as a stopwatch, the terminal velocity of a whiffle ball can be obtained to surprisingly high accuracy with only common household equipment. This classroom activity engages students in an apparently daunting task that nevertheless is tractable, using a simple model and mathematical techniques at their…

  12. Settings for Terminal Care.

    ERIC Educational Resources Information Center

    Corless, Inge B.

    1988-01-01

    Examines topics related to delivery of terminal care services: ability of various hospice programs to survive financially, contributions of various models of hospice care, impact of Medicare legislation on hospice movement, demonstration of unique hospice intervention, integration of spiritual care into hospice, and role of hospice in care of…

  13. Shipboard regasification terminal

    SciTech Connect

    Campbell, G.; Zednik, J.

    1999-07-01

    Mobil Technology Company and Mobil Shipping and Transportation Company have jointly developed a new combination of existing proven equipment to regasify LNG. Advantages of this Shipboard Regasification Terminal (SRT) include accelerated initial gas delivery schedule, low capital cost, delivery of smaller quantities of LNG at a competitive price and shorter term of LNG purchase and improved financing options. These advantages benefit both the supplier of LNG and the purchaser. SRT can be used as an interim supply to developing markets allowing the demand to grow while developing downstream infrastructure. This concept does not involve offshore transfer of cryogenic fluids while delivering near-ambient temperature pipeline quality gas at typical pipeline pressures. During times when gas is not required, the SRT ship can easily be returned to the trade of transporting and delivering LNG to conventional land based terminals. This paper will discuss the merits of Shipboard Regasification Terminals in general, cover the development of this concept and review the factors guiding the use of SRT vs. an onshore terminal.

  14. Ability of Serum Glial Fibrillary Acidic Protein, Ubiquitin C-Terminal Hydrolase-L1, and S100B To Differentiate Normal and Abnormal Head Computed Tomography Findings in Patients with Suspected Mild or Moderate Traumatic Brain Injury

    PubMed Central

    Ayaz, Syed I.; Lewis, Lawrence M.; Unden, Johan; Chen, James Y.; Mika, Valerie H.; Saville, Ben; Tyndall, Joseph A.; Nash, Marshall; Buki, Andras; Barzo, Pal; Hack, Dallas; Tortella, Frank C.; Schmid, Kara; Hayes, Ronald L.; Vossough, Arastoo; Sweriduk, Stephen T.; Bazarian, Jeffrey J.

    2016-01-01

    Abstract Head computed tomography (CT) imaging is still a commonly obtained diagnostic test for patients with minor head injury despite availability of clinical decision rules to guide imaging use and recommendations to reduce radiation exposure resulting from unnecessary imaging. This prospective multicenter observational study of 251 patients with suspected mild to moderate traumatic brain injury (TBI) evaluated three serum biomarkers' (glial fibrillary acidic protein [GFAP], ubiquitin C-terminal hydrolase-L1 [UCH-L1] and S100B measured within 6 h of injury) ability to differentiate CT negative and CT positive findings. Of the 251 patients, 60.2% were male and 225 (89.6%) had a presenting Glasgow Coma Scale score of 15. A positive head CT (intracranial injury) was found in 36 (14.3%). UCH-L1 was 100% sensitive and 39% specific at a cutoff value >40 pg/mL. To retain 100% sensitivity, GFAP was 0% specific (cutoff value 0 pg/mL) and S100B had a specificity of only 2% (cutoff value 30 pg/mL). All three biomarkers had similar values for areas under the receiver operator characteristic curve: 0.79 (95% confidence interval; 0.70–0.88) for GFAP, 0.80 (0.71–0.89) for UCH-L1, and 0.75 (0.65–0.85) for S100B. Neither GFAP nor UCH-L1 curve values differed significantly from S100B (p = 0.21 and p = 0.77, respectively). In our patient cohort, UCH-L1 outperformed GFAP and S100B when the goal was to reduce CT use without sacrificing sensitivity. UCH-L1 values <40 pg/mL could potentially have aided in eliminating 83 of the 215 negative CT scans. These results require replication in other studies before the test is used in actual clinical practice. PMID:26467555

  15. Dusty Termination Shocks

    SciTech Connect

    Ip, W.H.

    2004-09-15

    In astrophysical settings, termination shocks where strong stellar wind outflows interact with the surrounding environments tend to take place in dusty regions. Just to name a few, star formation regions, planetary nebulae, supernova remnants and active galactic nuclei are all good examples. Dynamics and evolution of the associated dust clouds could have important influences on the acceleration and composition of energetic particles resulting from the diffusive shock acceleration at the termination shocks. In this note we provide a brief review of previous work predating the recent detection of ACR Mg, Na, Si and S ions which might have originated from the Kuiper belt dust. Their compositional abundance might be diagnostic of the collisional history of the Kupier belt objects.

  16. Mobile Phone Terminal

    NASA Technical Reports Server (NTRS)

    1978-01-01

    In the photo, an employee of a real estate firm is contacting his office by means of HICOM, an advanced central terminal for mobile telephones. Developed by the Orlando Division of Martin Marietta Aerospace, Orlando, Florida, and manufactured by Harris Corporation's RF Division, Rochester, N.Y., HICOM upgrades service to users, provides better system management to telephone companies, and makes more efficient use of available mobile telephone channels through a computerized central control terminal. The real estate man, for example, was able to dial his office and he could also have direct-dialed a long distance number. Mobile phones in most areas not yet served by HICOM require an operator's assistance for both local and long distance calls. HICOM improves system management by automatically recording information on all calls for accurate billing, running continual performance checks on its own operation, and reporting any malfunctions to a central office.

  17. Shipboard fisheries management terminals

    NASA Technical Reports Server (NTRS)

    Nagler, R. G.; Sager, E. V.

    1980-01-01

    The needs of the National Marine Fisheries Service (NMGS), National Weather Service, and the U.S. Coast Guard for locational, biological, and environmental data were assessed. The fisheries conservation zones and the yellowfin tuna jurisdiction of the NMFS operates observer programs on foreign and domestic fishing vessels. Data input terminal and data transfer and processing technology are reviewed to establish available capability. A matrix of implementation options is generated to identify the benefits of each option, and preliminary cost estimates are made. Recommendations are made for incremental application of available off the shelf hardware to obtain improved performance and benefits within a well bounded cost. Terminal recommendations are made for three interdependent shipboard units emphasizing: (1) the determination of location and fishing activity; (2) hand held data inputting and formatting in the fishing work areas; and (3) data manipulation, merging, and editing.

  18. Ice age terminations.

    PubMed

    Cheng, Hai; Edwards, R Lawrence; Broecker, Wallace S; Denton, George H; Kong, Xinggong; Wang, Yongjin; Zhang, Rong; Wang, Xianfeng

    2009-10-09

    230Th-dated oxygen isotope records of stalagmites from Sanbao Cave, China, characterize Asian Monsoon (AM) precipitation through the ends of the third- and fourthmost recent ice ages. As a result, AM records for the past four glacial terminations can now be precisely correlated with those from ice cores and marine sediments, establishing the timing and sequence of major events. In all four cases, observations are consistent with a classic Northern Hemisphere summer insolation intensity trigger for an initial retreat of northern ice sheets. Meltwater and icebergs entering the North Atlantic alter oceanic and atmospheric circulation and associated fluxes of heat and carbon, causing increases in atmospheric CO2 and Antarctic temperatures that drive the termination in the Southern Hemisphere. Increasing CO2 and summer insolation drive recession of northern ice sheets, with probable positive feedbacks between sea level and CO2.

  19. Navy Multiband Terminal (NMT)

    DTIC Science & Technology

    2013-12-01

    Acquisition Management Information Retrieval Dev Est - Development Estimate DoD - Department of Defense DSN - Defense Switched Network Econ - Economic Eng...Memo Note for Shore (for MTBF and MTBCF): Represents IOT &E and Verification of Correction of Deficiencies testing results; mission impact deemed...insignificant due to multiple terminals at Shore site. Note for Sub (for MTBF, MTBCF and MTTR): Represents IOT &E hours; test duration limit for

  20. Amine terminated bisaspartimide polymer

    NASA Technical Reports Server (NTRS)

    Kumar, D. (Inventor); Fohlen, G. M. (Inventor); Parker, J. A. (Inventor)

    1986-01-01

    Novel amine terminated bisaspartimides are prepared by a Michael-type reaction of an aromatic bismalteimide and an aromatic diamine in an aprotic solvent. These bisaspartimides are thermally polymerized to yield tough, resinous polymers cross-lined through -NH- groups. Such polymers are useful in applications requiring materials with resistance to change at elevated temperatures, e.g., as lightweight laminates with graphite cloth, molding material prepregs, adhesives and insulating material.

  1. Remote terminal system evaluation

    NASA Technical Reports Server (NTRS)

    Phillips, T. L.; Grams, H. L.; Lindenlaub, J. C.; Schwingendorf, S. K.; Swain, P. H.; Simmons, W. R.

    1975-01-01

    An Earth Resources Data Processing System was developed to evaluate the system for training, technology transfer, and data processing. In addition to the five sites included in this project two other sites were connected to the system under separate agreements. The experience of these two sites is discussed. The results of the remote terminal project are documented in seven reports: one from each of the five project sites, Purdue University, and an overview report summarizing the other six reports.

  2. The Ethics of Terminal Care

    ERIC Educational Resources Information Center

    Agich, George J.

    1978-01-01

    Need for a critical and analytical approach to ethics of terminal care is suggested by considering a series of unexamined questions regarding justification of terminal care. If terminal care is a moral and ethical enterprise, such considerations must be given a more prominent place in discussions of the hospice movement. (Author)

  3. Iron-binding fragments from the carboxyl-terminal region of hen ovotransferrin.

    PubMed Central

    Williams, J

    1975-01-01

    1. When iron-saturated hen ovotransferrin was treated with subtilisin the N-terminal half was digested at a faster rate than the C-terminal half, allowing the latter to be isolated as a single-chain fragment of mol.wt 35000. 2. In mildly acid conditions iron-ovotransferrin loses iron preferentially from its N-terminal binding site. Trypsin digestion of the resulting monoferric ovotransferrin also gave rise to a C-terminal fragment. 3. Comparison of the N-terminal fragment with the C-terminal fragments shows differences in composition, peptide 'maps', CNBr-cleavage patterns and antigenic structures. The C-terminal fragments carry the carbohydrate group of ovotransferrin. 4. Both N-terminal and C-terminal fragments donate their bound iron to rabbit reticulocytes. Images PLATE 1 PLATE 2 PMID:811217

  4. Terminal weather information management

    NASA Technical Reports Server (NTRS)

    Lee, Alfred T.

    1990-01-01

    Since the mid-1960's, microburst/windshear events have caused at least 30 aircraft accidents and incidents and have killed more than 600 people in the United States alone. This study evaluated alternative means of alerting an airline crew to the presence of microburst/windshear events in the terminal area. Of particular interest was the relative effectiveness of conventional and data link ground-to-air transmissions of ground-based radar and low-level windshear sensing information on microburst/windshear avoidance. The Advanced Concepts Flight Simulator located at Ames Research Center was employed in a line oriented simulation of a scheduled round-trip airline flight from Salt Lake City to Denver Stapleton Airport. Actual weather en route and in the terminal area was simulated using recorded data. The microburst/windshear incident of July 11, 1988 was re-created for the Denver area operations. Six experienced airline crews currently flying scheduled routes were employed as test subjects for each of three groups: (1) A baseline group which received alerts via conventional air traffic control (ATC) tower transmissions; (2) An experimental group which received alerts/events displayed visually and aurally in the cockpit six miles (approx. 2 min.) from the microburst event; and (3) An additional experimental group received displayed alerts/events 23 linear miles (approx. 7 min.) from the microburst event. Analyses of crew communications and decision times showed a marked improvement in both situation awareness and decision-making with visually displayed ground-based radar information. Substantial reductions in the variability of decision times among crews in the visual display groups were also found. These findings suggest that crew performance will be enhanced and individual differences among crews due to differences in training and prior experience are significantly reduced by providing real-time, graphic display of terminal weather hazards.

  5. Terminal Analysis Study

    DTIC Science & Technology

    1976-06-01

    processor cannot provide data at a rate which is fast enough to fill the link, fill bits are inserted until the next line is ready. Each line has the...JWICROPRCXESSOR r^Zl*" MODERATELV MODERATE 7 l I FAST I HIGH Figure 3.19. General Data Proofing Trode-Of* ^peed than the...standard, .p.cify the p.oper manner > which terminals may Interface this store- and- forword message switching network. A2.3 AUTOSEVOCOM The current

  6. Acetylene terminated matrix resins

    NASA Technical Reports Server (NTRS)

    Goldfarb, I. J.; Lee, Y. C.; Arnold, F. E.; Helminiak, T. E.

    1985-01-01

    The synthesis of resins with terminal acetylene groups has provided a promising technology to yield high performance structural materials. Because these resins cure through an addition reaction, no volatile by-products are produced during the processing. The cured products have high thermal stability and good properties retention after exposure to humidity. Resins with a wide variety of different chemical structures between the terminal acetylene groups are synthesized and their mechanical properties studied. The ability of the acetylene cured polymers to give good mechanical properties is demonstrated by the resins with quinoxaline structures. Processibility of these resins can be manipulated by varying the chain length between the acetylene groups or by blending in different amounts of reactive deluents. Processing conditions similar to the state-of-the-art epoxy can be attained by using backbone structures like ether-sulfone or bis-phenol-A. The wide range of mechanical properties and processing conditions attainable by this class of resins should allow them to be used in a wide variety of applications.

  7. Termination: A Case Study.

    PubMed

    Friedberg, Ahron L

    2015-12-01

    In this article I posit and examine certain criteria and qualities for ending an analysis. The case study describes the end phase of a four-year psychoanalysis in which the patient's decision to move to another area forced the end of his analysis. We continued to explore and work through his core neurotic conflicts that included issues of competitive rivalry, dominance and submission, control, and anxiety about birth and death. A shift in the transference from me as a negative father to me as a supportive but competitive older brother was also examined in the context of ending treatment as well as other aspects of the transference. In addition, we analyzed the meaning of his ending treatment based on an extra-analytic circumstance. In discussing this phase of treatment, the definition and history of the term "termination" and its connotations are reviewed. Various criteria for completing an analysis are examined, and technical observations about this phase of treatment are investigated. It was found that while a significant shift in the transference occurred in this phase of the patient's analysis, conflicts related to the transference were not "resolved" in the classical sense. Terminating treatment was considered as a practical matter in which the patient's autonomy and sense of choice were respected and analyzed.

  8. Ligand Replacement Approach to Raman-Responded Molecularly Imprinted Monolayer for Rapid Determination of Penicilloic Acid in Penicillin.

    PubMed

    Zhang, Liying; Jin, Yang; Huang, Xiaoyan; Zhou, Yujie; Du, Shuhu; Zhang, Zhongping

    2015-12-01

    Penicilloic acid (PA) is a degraded byproduct of penicillin and often causes fatal allergies to humans, but its rapid detection in penicillin drugs remains a challenge due to its similarity to the mother structure of penicillin. Here, we reported a ligand-replaced molecularly imprinted monolayer strategy on a surface-enhanced Raman scattering (SERS) substrate for the specific recognition and rapid detection of Raman-inactive PA in penicillin. The bis(phenylenediamine)-Cu(2+)-PA complex was first synthesized and stabilized onto the surface of silver nanoparticle film that was fabricated by a bromide ion-added silver mirror reaction. A molecularly imprinted monolayer was formed by the further modification of alkanethiol around the stabilized complex on the Ag film substrate, and the imprinted recognition site was then created by the replacement of the complex template with Raman-active probe molecule p-aminothiophenol. When PA rebound into the imprinted site in the alkanethiol monolayer, the SERS signal of p-aminothiophenol exhibited remarkable enhancement with a detection limit of 0.10 nM. The imprinted monolayer can efficiently exclude the interference of penicillin and thus provides a selective determination of 0.10‰ (w/w) PA in penicillin, which is about 1 order of magnitude lower than the prescribed residual amount of 1.0‰. The strategy reported here is simple, rapid and inexpensive compared to the traditional chromatography-based methods.

  9. Channel and terminal description of the ACTS mobile terminal

    NASA Technical Reports Server (NTRS)

    Abbe, B. S.; Agan, M. J.; Girardey, C. C.; Jedrey, T. C.

    1994-01-01

    The Advanced Communications Technology Satellite (ACTS) Mobile Terminal (AMT) is a proof-of-concept K/Ka-band mobile satellite communications terminal under development by NASA at JPL. Currently the AMT is undergoing systems integration and testing in preparation for a July 1993 ACTS launch and the subsequent commencement of mobile experiments in the fall of 1993. The AMT objectives are presented, followed by a discussion of the AMT communications channel and the mobile terminal's design and performance.

  10. Channel and terminal description of the ACTS mobile terminal

    NASA Technical Reports Server (NTRS)

    Abbe, B. S.; Agan, M. J.; Girardey, C. C.; Jedrey, T. C.

    1993-01-01

    The Advanced Communications Technology Satellite (ACTS) Mobile Terminal (AMT) is a proof-of-concept K/Ka-band mobile satellite communications terminal under development by NASA at JPL. Currently the AMT is undergoing system integration and test in preparation for a July 1993 ACTS launch and the subsequent commencement of mobile experiments in the fall of 1993. The AMT objectives are presented followed by a discussion of the AMT communications channel and mobile terminal design and performance.

  11. The Effects of Termination on the Menominee

    ERIC Educational Resources Information Center

    Deer, Ada E.

    1973-01-01

    Topics discussed in this article are: (1) a brief pre-termination history of the Menominee Indians; (2) the enactment of termination; (3) the effects of termination on the Menominee; and (4) the need to repudiate termination. (NQ)

  12. Effects of alkali or acid treatment on the isomerization of amino acids.

    PubMed

    Ohmori, Taketo; Mutaguchi, Yuta; Doi, Katsumi; Ohshima, Toshihisa

    2012-10-01

    The effect of alkali treatment on the isomerization of amino acids was investigated. The 100×D/(D+L) values of amino acids from peptide increased with increase in the number of constituent amino acid residues. Furthermore, the N-terminal amino acid of a dipeptide was isomerized to a greater extent than the C-terminal residue.

  13. Homochiral preference in peptide synthesis in ribosome: role of amino terminal, peptidyl terminal, and U2620.

    PubMed

    Thirumoorthy, Krishnan; Nandi, Nilashis

    2007-08-23

    Experimental studies have shown that peptide synthesis in ribosome exhibits a homochiral preference. We present, for the first time, an analysis of the origin of the phenomenon using hybrid quantum chemical studies based on a model of peptidyl transferase center from the crystal structure of the ribosomal part of Haloarcula marismortui. The study quantitatively shows that the observed homochiral preference is due to the difference in the nonbonded interaction between amino acids at the A- and P-terminals as well as due to the difference in interaction with the U2620 residue. A major part of the discrimination comes from the variation of nonbonded interaction of rotating A-terminal during the approach of the former toward the P-terminal. The difference indicates that, during the rotatory motion between A- and P-terminals for the proximal positioning of the reactant for reaction to occur, the interaction for a L-L pair is far less repulsive compared to the same process for a D-L pair. The activation barriers for L-L and D-L pairs of the neutral state of phenylalanine leading to corresponding dipeptides are also compared. The corresponding difference in rate constants is 40-fold. The study provides an understanding of how preferred addition of L-L pairs of amino acids rather than D-L pairs leads to retention of homochirality in peptides.

  14. Highly specific and sensitive non-enzymatic determination of uric acid in serum and urine by extended gate field effect transistor sensors.

    PubMed

    Guan, Weihua; Duan, Xuexin; Reed, Mark A

    2014-01-15

    A potentiometric non-enzymatic sensor using off-chip extended-gate field effect transistor (EGFET) with a ferrocenyl-alkanethiol modified gold electrode is demonstrated for determining the uric acid concentration in human serum and urine. Hexacyanoferrate (II) and (III) ions are used as redox reagent. This potentiometric sensor measures the interface potential on the ferrocene immobilized gold electrode, which is modulated by the redox reaction between uric acid and hexacyanoferrate ions. The device shows a near Nernstian response to uric acid and is highly specific. The interference that comes from glucose, bilirubin, ascorbic acid and hemoglobin is negligible in normal concentration range of these interferents. The sensor also exhibits excellent long term reliability. This extended gate field effect transistor based sensors can be used as a point of care UA testing tool, due to the small size, low cost, and low sample volume consumption.

  15. [Terminal ballistics. 3].

    PubMed

    Marini, F; Mangiante, G; Dagradi, V; Radin, S; Carolo, F; Giarolli, M; Della Giacoma, G; Tosi, D; Merico, G; Tenci, A

    1993-01-01

    This brief chapter, focusing essentially on a single topic, has been written in homage to Emile Theodor Kocker, a masterful exponent of the art of surgery and founder of the culture of terminal ballistics. For most of the literature we are indebted to Fackler and Dougherty, who, with the particular grasp, and fair of historians, act as guides on a trial which is only apparently retrograde, but which actually bears eloquent witness to the fact that even in the most physically tangible of arts, namely the art of surgery, inspired curiosity may help us to go well beyond the limits of our day and age. This chapter is also dedicated to the memory of another great surgeon, Vittorio Pettinari, who for one of the authors was an incomparable mentor and past-master of such curiosity.

  16. 75 FR 13644 - TORP Terminal LP, Bienville Offshore Energy Terminal Liquefied Natural Gas Deepwater Port License...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-22

    ... Maritime Administration TORP Terminal LP, Bienville Offshore Energy Terminal Liquefied Natural Gas...) for the TORP Terminal LP, Bienville Offshore Energy Terminal (BOET) Liquefied Natural Gas (LNG..., both are identified in FOR FURTHER INFORMATION CONTACT. Summary of the Application TORP Terminal...

  17. Sequence requirements for Lon-dependent degradation of the Escherichia coli transcription activator SoxS: identification of the SoxS residues critical to proteolysis and specific inhibition of in vitro degradation by a peptide comprised of the N-terminal 21 amino acid residues.

    PubMed

    Shah, Ishita M; Wolf, Richard E

    2006-03-31

    When Escherichia coli encounter redox-cycling compounds that endogenously generate superoxide, the cell's defense response is initiated by the de novo synthesis of SoxS, which then activates transcription of the genes of the SoxRS regulon. Recently, we showed that after the oxidative stress is relieved, the SoxRS system resets by an active process wherein SoxS synthesis ceases and the intrinsically unstable SoxS protein is rapidly degraded, primarily by Lon protease. Here, we use deletion mutants and a library of alanine-stretch mutants of the entire protein to identify the SoxS features responsible for Lon-dependent proteolysis in vivo. We found that the 17 amino acid residues at the SoxS N terminus play the primary role in protease recognition and that the addition of the N-terminal 21 residues of SoxS to the otherwise stable green fluorescent protein is sufficient to signal the chimera for Lon-dependent degradation. With a minimal in vitro degradation system, we confirm the intrinsic instability of SoxS and the sequence requirements for Lon-dependent degradation. Lastly, we demonstrate that the addition of a peptide comprised of the 21 N-terminal amino acid residues of SoxS is able to inhibit specifically the in vitro proteolysis of SoxS.

  18. Is Lake Tahoe Terminal?

    NASA Astrophysics Data System (ADS)

    Coats, R. N.; Reuter, J.; Heyvaert, A.; Lewis, J.; Sahoo, G. B.; Schladow, G.; Thorne, J. H.

    2014-12-01

    ) the climatic water deficit will increase, especially at high elevations that will be most affected by the loss of snow, with likely consequences for existing vegetation and fire frequency. Hydrologically, Lake Tahoe is intermittently terminal; in a medical sense it is not yet terminal, but its condition—especially its valued clarity and deep blue color--is serious.

  19. SCATHA mission termination report

    NASA Technical Reports Server (NTRS)

    Stakkestad, Kjell; Fennessey, Richard

    1993-01-01

    nearly complete lack of available telemetry data, large undamped motion of the long booms, inadequacies in attitude determination software, and an error in the fuel level calculation software. This paper discusses the various proposed termination plans and execution of the selected one. Attitude determination methodologies, nutation from maneuvers, and effects of the flexible booms on the termination mission are presented and analyzed from a satellite analyst point of view.

  20. SCATHA mission termination report

    NASA Astrophysics Data System (ADS)

    Stakkestad, Kjell; Fennessey, Richard

    1993-02-01

    nearly complete lack of available telemetry data, large undamped motion of the long booms, inadequacies in attitude determination software, and an error in the fuel level calculation software. This paper discusses the various proposed termination plans and execution of the selected one. Attitude determination methodologies, nutation from maneuvers, and effects of the flexible booms on the termination mission are presented and analyzed from a satellite analyst point of view.

  1. [Terminal ballistics. 1].

    PubMed

    Mangiante, G; Dagradi, V; Radin, S; Carolo, F; Giarolli, M; Tenci, A; Merico, G; Tosi, D; Acerbi, A; Della Giacoma, G

    1993-01-01

    We have chosen to conceive of terminal ballistics as a violent and extremely rapid confrontation between two forms of resistance before the final state of rest is reached. This definition, which cannot help but don the admittedly loud and outlandish garb of physics, is the most promising for the purposes of biological interpretation. The main characters on this stage are two, but only one of these really plays the lead, namely the human target, which acts out the basic roles inherent in its physical make-up; the other, the bullet, remains a background figure, frozen in its walk-on part, and ready for the next performance. This modus operandi, which is no simplification, but rather an academic necessity, enables us to focus on images which stand out more clearly as a result of an intensive macroscopic spotlight which brings out the features of the individual phenomena, broken down into a succession of close-ups, and subtracts them from the cold physical nature of this or that form of inert matter, which here is merely an occasional, disagreeable witness, or even more, a standing from time to time for but one of the infinite facets of the biological composite being. Here, then, faced with a kind of exploded macrophotograph of a complex kaleidoscope, we see the animal universe, of which we capture so far the plasticity, the subdivisibility, the anisotropy and the cavitation.

  2. Terminal Descent Sensor Simulation

    NASA Technical Reports Server (NTRS)

    Chen, Curtis W.

    2009-01-01

    Sulcata software simulates the operation of the Mars Science Laboratory (MSL) radar terminal descent sensor (TDS). The program models TDS radar antennas, RF hardware, and digital processing, as well as the physics of scattering from a coherent ground surface. This application is specific to this sensor and is flexible enough to handle end-to-end design validation. Sulcata is a high-fidelity simulation and is used for performance evaluation, anomaly resolution, and design validation. Within the trajectory frame, almost all internal vectors are represented in whatever coordinate system is used to represent platform position. The trajectory frame must be planet-fixed. The platform body frame is specified relative to arbitrary reference points relative to the platform (spacecraft or test vehicle). Its rotation is a function of time from the trajectory coordinate system specified via dynamics input (file for open loop, callback for closed loop). Orientation of the frame relative to the body is arbitrary, but constant over time. The TDS frame must have a constant rotation and translation from the platform body frame specified at run time. The DEM frame has an arbitrary, but time-constant, rotation and translation with respect to the simulation frame specified at run time. It has the same orientation as sigma0 frame, but is possibly translated. Surface sigma0 has the same arbitrary rotation and translation as DEM frame.

  3. Anchored terminal conductor

    SciTech Connect

    Milewski, M.A.; Delmolino, W.P.

    1986-08-19

    An electrochemical cell is described comprising a cell container which is closed by a resilient insulative cell top and an electrode conductor inserted through the cell top and into an electrode of the cell, with the electrode conductor being physically and electrically accessible to the exterior of the cell whereby it functions as a terminal for the electrode, and wherein a portion of the electrode conductor is enclosed within the cell top, characterized in that the cell further comprises means for substantially restraining movement of the electrode conductor relative to the cell top. The electrode conductor has a nail configuration comprising a head and a shank with the head of the nail providing the external physical and electrical accessibility, wherein the restraining means is integrated with the shank of the nail. The restraining means is positioned on the shank, interior to the cell container and below the interior surface of the cell top and in close juxtaposition to the interior surface. The restraining means comprises a circumferential barb longitudinally disposed on the shank and having an upper portion which engages the interior surface to provide the substantial restraining of movement.

  4. War Termination: A Selected Bibliography

    DTIC Science & Technology

    2010-10-01

    Peace Research 33, no. 4 (November 1996): 491-496. JSTOR Phinney, Catherine. "Enhancing Conflict Termination through Problem Solving...96." Journal of Peace Research 34, no. 3 (August 1997): 339-358. JSTOR Bibliographies Bibliography Branch, comp. Conflict Termination

  5. 49 CFR 1242.27 - Coal marine terminals, ore marine terminals, TOFC/COFC terminals, other marine terminals, motor...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    .../COFC terminals, other marine terminals, motor vehicle loading and distribution facilities, and facilities for other specialized service operations (accounts XX-13-29 to XX-13-35, inclusive). 1242.27..., motor vehicle loading and distribution facilities, and facilities for other specialized...

  6. Biochemistry of terminal deoxynucleotidyltransferase. Identification and unity of ribo- and deoxyribonucleoside triphosphate binding site in terminal deoxynucleotidyltransferase

    SciTech Connect

    Pandey, V.N.; Modak, M.J.

    1989-01-15

    Terminal deoxynucleotidyltransferase is the only DNA polymerase that is strongly inhibited in the presence of ATP. We have labeled calf terminal deoxynucleotidyltransferase with (/sup 32/P)ATP in order to identify its binding site in terminal deoxynucleotidyltransferase. The specificity of ATP cross-linking to terminal deoxynucleotidyltransferase is shown by the competitive inhibition of the overall cross-linking reaction by deoxynucleoside triphosphates, as well as the ATP analogs Ap4A and Ap5A. Tryptic peptide mapping of (/sup 32/P)ATP-labeled enzyme revealed a peptide fraction that contained the majority of cross-linked ATP. The properties, chromatographic characteristics, amino acid composition, and sequence analysis of this peptide fraction were identical with those found associated with dTTP cross-linked terminal deoxynucleotidyl-transferase peptide. The involvement of the same 2 cysteine residues in the crosslinking of both nucleotides further confirmed the unity of the ATP and dTTP binding domain that contains residues 224-237 in the primary amino acid sequence of calf terminal deoxynucleotidyltransferase.

  7. Sargaquinoic acid isolated from Sargassum siliquastrum inhibits lipopolysaccharide-induced nitric oxide production in macrophages via modulation of nuclear factor-κB and c-Jun N-terminal kinase pathways.

    PubMed

    Kang, Gyeoung-Jin; Han, Sang-Chul; Yoon, Weon-Jong; Koh, Young-Sang; Hyun, Jin-Won; Kang, Hee-Kyoung; Youl Cho, Jae; Yoo, Eun-Sook

    2013-02-01

    Nitric oxide (NO) is a crucial molecule in inflammatory diseases and is synthesized from L-arginine by a specific enzyme, NO synthase (NOS). The expression of inducible NOS (iNOS) is activated in macrophages by various stimuli, such as lipopolysaccharide (LPS), a wall component of gram-negative bacteria. LPS binds to toll-like receptor 4 (TLR4) on the macrophage surface and activates several downstream signaling pathways, including mitogen-activated protein kinase (MAPK) and nuclear factor (NF)-κB pathways. This study investigated whether sargaquinoic acid isolated from Sargassum siliquastrum might have anti-inflammatory activity and interfere with NO production in macrophages by disrupting LPS-induced signaling. This study was conducted in vitro using RAW264.7 murine macrophages. LPS-stimulated cells were treated with sargaquinoic acid, and the effects on NO production, iNOS expression, and involvement of the NF-κB signaling pathway were investigated by Griess assay, western blotting, and confocal microscopy. The results demonstrated that sargaquinoic acid inhibited the production of NO and the expression of the iNOS protein in LPS-stimulated RAW264.7 macrophages. Moreover, sargaquinoic acid inhibited the degradation of inhibitory-κB protein (IκB)-α and the nuclear translocation of NF-κB, a key transcription factor for the regulation of iNOS expression. Also, sargaquinoic acid influenced the phosphorylation of JNK1/2 MAPK, except ERK1/2 and p38 MAPKs, stimulated by LPS. These results suggest that sargaquinoic acid specifically prevents NO production in macrophages via the blockade of NF-κB activation and may thus have therapeutic applications in various inflammatory diseases.

  8. The use of mobile satellite communication terminals

    NASA Astrophysics Data System (ADS)

    Law, P. A.

    The role of small portable terminals in military satellite systems is examined; the discussion embraces terminals with an antenna reflector diameter of seven meters or less. Emphasis is placed on the specification of MARMOSET (Marconi Mobile Satellite Earth Terminal). Also considered are ship-borne satellite terminals, the improved SCOT terminal, interoperability, reduced downlink power, and reliability and availability.

  9. 32 CFR 34.51 - Termination.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., in which case the two parties shall agree upon the termination conditions, including the effective date and, in the case of partial termination, the portion to be terminated. (3) By the recipient upon... effective date, and, in the case of partial termination, the portion to be terminated. The recipient...

  10. 32 CFR 32.61 - Termination.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... consent of the recipient, in which case the two parties shall agree upon the termination conditions, including the effective date and, in the case of partial termination, the portion to be terminated; or (3... for such termination, the effective date, and, in the case of partial termination, the portion to...

  11. Low Earth Orbiter: Terminal

    NASA Technical Reports Server (NTRS)

    Kremer, Steven E.; Bundick, Steven N.

    1999-01-01

    In response to the current government budgetary environment that requires the National Aeronautics and Space Administration (NASA) to do more with less, NASA/Goddard Space Flight Center's Wallops Flight Facility has developed and implemented a class of ground stations known as a Low Earth Orbiter-Terminal (LEO-T). This development thus provides a low-cost autonomous ground tracking service for NASA's customers. More importantly, this accomplishment provides a commercial source to spacecraft customers around the world to purchase directly from the company awarded the NASA contract to build these systems. A few years ago, NASA was driven to provide more ground station capacity for spacecraft telemetry, tracking, and command (TT&C) services with a decreasing budget. NASA also made a decision to develop many smaller, cheaper satellites rather than a few large spacecraft as done in the past. In addition, university class missions were being driven to provide their own TT&C services due to the increasing load on the NASA ground-tracking network. NASA's solution for this ever increasing load was to use the existing large aperture systems to support those missions requiring that level of performance and to support the remainder of the missions with the autonomous LEO-T systems. The LEO-T antenna system is a smaller, cheaper, and fully autonomous unstaffed system that can operate without the existing NASA support infrastructure. The LEO-T provides a low-cost, reliable space communications service to the expanding number of low-earth orbiting missions around the world. The system is also fostering developments that improve cost-effectiveness of autonomous-class capabilities for NASA and commercial space use. NASA has installed three LEO-T systems. One station is at the University of Puerto Rico, the second system is installed at the Poker Flat Research Range near Fairbanks, Alaska, and the third system is installed at NASA's Wallops Flight Facility in Virginia. This paper

  12. Smart sensor for terminal homing

    NASA Astrophysics Data System (ADS)

    Panda, D.; Aggarwal, R.; Hummel, R.

    1980-01-01

    The practical scene matching problem is considered to present certain complications which must extend classical image processing capabilities. Certain aspects of the scene matching problem which must be addressed by a smart sensor for terminal homing are discussed. First a philosophy for treating the matching problem for the terminal homing scenario is outlined. Then certain aspects of the feature extraction process and symbolic pattern matching are considered. It is thought that in the future general ideas from artificial intelligence will be more useful for terminal homing requirements of fast scene recognition and pattern matching.

  13. 77 FR 38128 - Withdrawal of TORP Terminal LP, Bienville Offshore Energy Terminal Liquefied Natural Gas (LNG...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-26

    ... Maritime Administration Withdrawal of TORP Terminal LP, Bienville Offshore Energy Terminal Liquefied... Terminal LP's (TORP) withdrawal of the deepwater port license application for the proposed Bienville Offshore Energy Terminal (BOET). All actions related to the processing and agency coordination...

  14. Balanced Branching in Transcription Termination

    NASA Technical Reports Server (NTRS)

    Harrington, K. J.; Laughlin, R. B.; Liang, S.

    2001-01-01

    The theory of stochastic transcription termination based on free-energy competition requires two or more reaction rates to be delicately balanced over a wide range of physical conditions. A large body of work on glasses and large molecules suggests that this should be impossible in such a large system in the absence of a new organizing principle of matter. We review the experimental literature of termination and find no evidence for such a principle but many troubling inconsistencies, most notably anomalous memory effects. These suggest that termination has a deterministic component and may conceivably be not stochastic at all. We find that a key experiment by Wilson and von Hippel allegedly refuting deterministic termination was an incorrectly analyzed regulatory effect of Mg(2+) binding.

  15. Terminal attractors in neural networks

    NASA Technical Reports Server (NTRS)

    Zak, Michail

    1989-01-01

    A new type of attractor (terminal attractors) for content-addressable memory, associative memory, and pattern recognition in artificial neural networks operating in continuous time is introduced. The idea of a terminal attractor is based upon a violation of the Lipschitz condition at a fixed point. As a result, the fixed point becomes a singular solution which envelopes the family of regular solutions, while each regular solution approaches such an attractor in finite time. It will be shown that terminal attractors can be incorporated into neural networks such that any desired set of these attractors with prescribed basins is provided by an appropriate selection of the synaptic weights. The applications of terminal attractors for content-addressable and associative memories, pattern recognition, self-organization, and for dynamical training are illustrated.

  16. Discovery Performs Terminal Initiation Burn

    NASA Video Gallery

    The terminal initiation burn, a left Orbital Maneuvering System engine firing that gave Discovery one last big push toward the space station, took place Feb. 26, 2011 at 10:33 a.m. The burn lasted ...

  17. Propagation Terminal Design and Measurements

    NASA Technical Reports Server (NTRS)

    Nessel, James

    2015-01-01

    The NASA propagation terminal has been designed and developed by the Glenn Research Center and is presently deployed at over 5 NASA and partner ground stations worldwide collecting information on the effects of the atmosphere on Ka-band and millimeter wave communications links. This lecture provides an overview of the fundamentals and requirements of the measurement of atmospheric propagation effects and, specifically, the types of hardware and digital signal processing techniques employed by current state-of-the-art propagation terminal systems.

  18. 15 CFR 286.12 - Terminations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... STANDARDS AND TECHNOLOGY, DEPARTMENT OF COMMERCE ACCREDITATION AND ASSESSMENT PROGRAMS NATIONAL VOLUNTARY CONFORMITY ASSESSMENT SYSTEM EVALUATION (NVCASE) PROGRAM § 286.12 Terminations. (a) Voluntary termination. Any participant may voluntarily terminate participation at any time by written notification to...

  19. Amino acid substitutions V63I or A37S/I61T/V63I/V100A in the PA N-terminal domain increase the virulence of H7N7 influenza A virus

    PubMed Central

    Hu, Meng; Chu, Hin; Zhang, Ke; Singh, Kailash; Li, Cun; Yuan, Shuofeng; Chow, Billy K. C.; Song, Wenjun; Zhou, Jie; Zheng, Bo-Jian

    2016-01-01

    The PA N-terminal domain (PA-Nter) is essential for viral transcription and replication. Here we identified PA-Nter substitutions A37S, I61T, V63I and V100A in recently emerged avian influenza A viruses (IAVs) with potential effect on virus pathogenicity and/or host adaptation. We introduced the identified PA-Nter substitutions into avian H7N7 IAV by reverse genetics. Our results showed that single substitution V63I and combined substitutions, I61T/V63I and A37S/I61T/V63I/V100A (Mfour), significantly increased virus growth capacity in mammalian cells. Meanwhile, these substitutions conferred higher virus transcription/replication capacity by producing more mRNA, cRNA and vRNA. Consistently, the polymerase activity and the endonuclease activity were enhanced by these PA-Nter substitutions. Notably, substitutions V63I and Mfour strongly increased virus replication and virulence in mice. Collectively, our findings demonstrated that the PA-Nter substitutions V63I and Mfour enhanced IAV pathogenicity through modification of the polymerase activity and the endonuclease activity, which added to the evolving knowledge of IAV virulence determinants. PMID:27886255

  20. New roles for old modifications: emerging roles of N-terminal post-translational modifications in development and disease.

    PubMed

    Tooley, John G; Schaner Tooley, Christine E

    2014-12-01

    The importance of internal post-translational modification (PTM) in protein signaling and function has long been known and appreciated. However, the significance of the same PTMs on the alpha amino group of N-terminal amino acids has been comparatively understudied. Historically considered static regulators of protein stability, additional functional roles for N-terminal PTMs are now beginning to be elucidated. New findings show that N-terminal methylation, along with N-terminal acetylation, is an important regulatory modification with significant roles in development and disease progression. There are also emerging studies on the enzymology and functional roles of N-terminal ubiquitylation and N-terminal propionylation. Here, will discuss the recent advances in the functional studies of N-terminal PTMs, recount the new N-terminal PTMs being identified, and briefly examine the possibility of dynamic N-terminal PTM exchange.

  1. New roles for old modifications: Emerging roles of N-terminal post-translational modifications in development and disease

    PubMed Central

    Tooley, John G; Schaner Tooley, Christine E

    2014-01-01

    The importance of internal post-translational modification (PTM) in protein signaling and function has long been known and appreciated. However, the significance of the same PTMs on the alpha amino group of N-terminal amino acids has been comparatively understudied. Historically considered static regulators of protein stability, additional functional roles for N-terminal PTMs are now beginning to be elucidated. New findings show that N-terminal methylation, along with N-terminal acetylation, is an important regulatory modification with significant roles in development and disease progression. There are also emerging studies on the enzymology and functional roles of N-terminal ubiquitylation and N-terminal propionylation. Here, will discuss the recent advances in the functional studies of N-terminal PTMs, recount the new N-terminal PTMs being identified, and briefly examine the possibility of dynamic N-terminal PTM exchange. PMID:25209108

  2. Termination of DNA replication is required for cell division in Escherichia coli.

    PubMed Central

    Grossman, N; Rosner, E; Ron, E Z

    1989-01-01

    The correlation between termination of DNA replication and cell division in Escherichia coli was studied under conditions in which DNA replication was slowed down without inducing SOS functions. The experimental system used involved amino acid starvation of synchronized cells in the presence of methionine. The results further support the essential correlation between termination of DNA replication and initiation of division processes. PMID:2644214

  3. 7 CFR 1206.22 - Terminate.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE MANGO PROMOTION, RESEARCH, AND INFORMATION Mango Promotion, Research, and Information Order Definitions § 1206.22 Terminate. Terminate...

  4. 7 CFR 1206.22 - Terminate.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE MANGO PROMOTION, RESEARCH, AND INFORMATION Mango Promotion, Research, and Information Order Definitions § 1206.22 Terminate. Terminate...

  5. 7 CFR 1206.22 - Terminate.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE MANGO PROMOTION, RESEARCH, AND INFORMATION Mango Promotion, Research, and Information Order Definitions § 1206.22 Terminate. Terminate...

  6. 7 CFR 1206.22 - Terminate.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE MANGO PROMOTION, RESEARCH, AND INFORMATION Mango Promotion, Research, and Information Order Definitions § 1206.22 Terminate. Terminate...

  7. 7 CFR 1206.22 - Terminate.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE MANGO PROMOTION, RESEARCH, AND INFORMATION Mango Promotion, Research, and Information Order Definitions § 1206.22 Terminate. Terminate...

  8. Report on Investigations of Aviation Wires and Cables, Their Fastenings and Terminal Connections

    NASA Technical Reports Server (NTRS)

    Sunderlang, C C; Horn, H J; Green, D

    1917-01-01

    Report presents results that show that it is possible to furnish efficient terminal connections that would allow for repairs for aviation wires and cables and eliminate the use of acid solder and blow torch.

  9. Conformal mapping for multiple terminals

    NASA Astrophysics Data System (ADS)

    Wang, Weimin; Ma, Wenying; Wang, Qiang; Ren, Hao

    2016-11-01

    Conformal mapping is an important mathematical tool that can be used to solve various physical and engineering problems in many fields, including electrostatics, fluid mechanics, classical mechanics, and transformation optics. It is an accurate and convenient way to solve problems involving two terminals. However, when faced with problems involving three or more terminals, which are more common in practical applications, existing conformal mapping methods apply assumptions or approximations. A general exact method does not exist for a structure with an arbitrary number of terminals. This study presents a conformal mapping method for multiple terminals. Through an accurate analysis of boundary conditions, additional terminals or boundaries are folded into the inner part of a mapped region. The method is applied to several typical situations, and the calculation process is described for two examples of an electrostatic actuator with three electrodes and of a light beam splitter with three ports. Compared with previously reported results, the solutions for the two examples based on our method are more precise and general. The proposed method is helpful in promoting the application of conformal mapping in analysis of practical problems.

  10. Conformal mapping for multiple terminals.

    PubMed

    Wang, Weimin; Ma, Wenying; Wang, Qiang; Ren, Hao

    2016-11-10

    Conformal mapping is an important mathematical tool that can be used to solve various physical and engineering problems in many fields, including electrostatics, fluid mechanics, classical mechanics, and transformation optics. It is an accurate and convenient way to solve problems involving two terminals. However, when faced with problems involving three or more terminals, which are more common in practical applications, existing conformal mapping methods apply assumptions or approximations. A general exact method does not exist for a structure with an arbitrary number of terminals. This study presents a conformal mapping method for multiple terminals. Through an accurate analysis of boundary conditions, additional terminals or boundaries are folded into the inner part of a mapped region. The method is applied to several typical situations, and the calculation process is described for two examples of an electrostatic actuator with three electrodes and of a light beam splitter with three ports. Compared with previously reported results, the solutions for the two examples based on our method are more precise and general. The proposed method is helpful in promoting the application of conformal mapping in analysis of practical problems.

  11. Conformal mapping for multiple terminals

    PubMed Central

    Wang, Weimin; Ma, Wenying; Wang, Qiang; Ren, Hao

    2016-01-01

    Conformal mapping is an important mathematical tool that can be used to solve various physical and engineering problems in many fields, including electrostatics, fluid mechanics, classical mechanics, and transformation optics. It is an accurate and convenient way to solve problems involving two terminals. However, when faced with problems involving three or more terminals, which are more common in practical applications, existing conformal mapping methods apply assumptions or approximations. A general exact method does not exist for a structure with an arbitrary number of terminals. This study presents a conformal mapping method for multiple terminals. Through an accurate analysis of boundary conditions, additional terminals or boundaries are folded into the inner part of a mapped region. The method is applied to several typical situations, and the calculation process is described for two examples of an electrostatic actuator with three electrodes and of a light beam splitter with three ports. Compared with previously reported results, the solutions for the two examples based on our method are more precise and general. The proposed method is helpful in promoting the application of conformal mapping in analysis of practical problems. PMID:27830746

  12. Relationships between Poly(ethylene glycol) Modifications on RNA-Spherical Nucleic Acid Conjugates and Cellular Uptake and Circulation Time.

    PubMed

    Chinen, Alyssa B; Ferrer, Jennifer R; Merkel, Timothy J; Mirkin, Chad A

    2016-11-16

    Two synthetic approaches that allow one to control PEG content within spherical nucleic acids (SNAs) have been developed. One approach begins with RNA-modified gold nanoparticles followed by a backfill of PEG 2K alkanethiols, and the other involves co-adsorption of the two entities on a gold nanoparticle template. These two methods have been used to explore the role of PEG density on the chemical and biological properties of RNA-SNAs. Such studies show that while increasing the extent of PEGylation within RNA-SNAs extends their blood circulation half-life in mice, it also results in decreased cellular uptake. Modified ELISA assays show that constructs, depending upon RNA and PEG content, have markedly different affinities for class A scavenger receptors, the entities responsible, in part, for cellular internalization of SNAs. In designing SNAs for therapeutic purposes, these competing factors must be considered and appropriately adjusted depending upon the desired use.

  13. Balanced Branching in Transcription Termination

    NASA Technical Reports Server (NTRS)

    Harrington, K. J.; Laughlin, R. B.; Liang, S.

    2000-01-01

    The theory of stochastic transcription termination based on free-energy competition requires two or more reaction rates to be delicately balanced over a wide range of physical conditions. A large body of work on glasses and large molecules suggests that this should be impossible in such a large system in the absence of a new organizing principle of matter. We review the experimental literature of termination and find no evidence for such a principle but many troubling inconsistencies, most notably anomalous memory effects. These suggest that term ination has a deterministic component and may conceivably be not stochastic at all. We find that a key experiment by Wilson and von Hippel allegedly refuting deterministic termination was an incorrectly analyzed regulatory effect of Mg(2+) binding.

  14. Digital autonomous terminal access communications

    NASA Technical Reports Server (NTRS)

    Novacki, S.

    1987-01-01

    A significant problem for the Bus Monitor Unit is to identify the source of a given transmission. This problem arises from the fact that the label which identifies the source of the transmission as it is put into the bus is intercepted by the Digital Autonomous Terminal Access Communications (DATAC) terminal and removed from the transmission. Thus, a given subsystem will see only data associated with a label and never the identifying label itself. The Bus Monitor must identify the source of the transmission so as to be able to provide some type of error identification/location in the event that some problem with the data transmission occurs. Steps taken to alleviate this problem by modifications to the DATAC terminal are discussed.

  15. Chromatin condensation during terminal erythropoiesis.

    PubMed

    Zhao, Baobing; Yang, Jing; Ji, Peng

    2016-09-02

    Mammalian terminal erythropoiesis involves gradual but dramatic chromatin condensation steps that are essential for cell differentiation. Chromatin and nuclear condensation is followed by a unique enucleation process, which is believed to liberate more spaces for hemoglobin enrichment and enable the generation of a physically flexible mature red blood cell. Although these processes have been known for decades, the mechanisms are still unclear. Our recent study reveals an unexpected nuclear opening formation during mouse terminal erythropoiesis that requires caspase-3 activity. Major histones, except H2AZ, are partially released from the opening, which is important for chromatin condensation. Block of the nuclear opening through caspase inhibitor or knockdown of caspase-3 inhibits chromatin condensation and enucleation. We also demonstrate that nuclear opening and histone release are cell cycle regulated. These studies reveal a novel mechanism for chromatin condensation in mammalia terminal erythropoiesis.

  16. Differential Contributions of Tacaribe Arenavirus Nucleoprotein N-Terminal and C-Terminal Residues to Nucleocapsid Functional Activity

    PubMed Central

    D'Antuono, Alejandra; Loureiro, Maria Eugenia; Foscaldi, Sabrina; Marino-Buslje, Cristina

    2014-01-01

    ABSTRACT The arenavirus nucleoprotein (NP) is the main protein component of viral nucleocapsids and is strictly required for viral genome replication mediated by the L polymerase. Homo-oligomerization of NP is presumed to play an important role in nucleocapsid assembly, albeit the underlying mechanism and the relevance of NP-NP interaction in nucleocapsid activity are still poorly understood. Here, we evaluate the contribution of the New World Tacaribe virus (TCRV) NP self-interaction to nucleocapsid functional activity. We show that alanine substitution of N-terminal residues predicted to be available for NP-NP interaction strongly affected NP self-association, as determined by coimmunoprecipitation assays, produced a drastic inhibition of transcription and replication of a TCRV minigenome RNA, and impaired NP binding to RNA. Mutagenesis and functional analysis also revealed that, while dispensable for NP self-interaction, key amino acids at the C-terminal domain were essential for RNA synthesis. Furthermore, mutations at these C-terminal residues rendered NP unable to bind RNA both in vivo and in vitro but had no effect on the interaction with the L polymerase. In addition, while all oligomerization-defective variants tested exhibited unaltered capacities to sustain NP-L interaction, NP deletion mutants were fully incompetent to bind L, suggesting that, whereas NP self-association is dispensable, the integrity of both the N-terminal and C-terminal domains is required for binding the L polymerase. Overall, our results suggest that NP self-interaction mediated by the N-terminal domain may play a critical role in TCRV nucleocapsid assembly and activity and that the C-terminal domain of NP is implicated in RNA binding. IMPORTANCE The mechanism of arenavirus functional nucleocapsid assembly is still poorly understood. No detailed information is available on the nucleocapsid structure, and the regions of full-length NP involved in binding to viral RNA remain to be

  17. Chemically Functional Alkanethiol Derivitized Magnetic Nanoparticles

    DTIC Science & Technology

    2003-01-01

    agents in medical imaging technologies7, and ’spintronics’ 8 (i.e., spin-based data transfer and storage). For example, Co and FePt nanoparticles have been...with a personal computer. Pt microelectrodes (25pin diameter) were created by flame-sealing Pt microwire (Alfa Aesar) in glass capillaries. The sealed

  18. Airborne Satcom Terminal Research at NASA Glenn

    NASA Technical Reports Server (NTRS)

    Hoder, Doug; Zakrajsek, Robert

    2002-01-01

    NASA Glenn has constructed an airborne Ku-band satellite terminal, which provides wideband full-duplex ground-aircraft communications. The terminal makes use of novel electronically-steered phased array antennas and provides IP connectivity to and from the ground. The satcom terminal communications equipment may be easily changed whenever a new configuration is required, enhancing the terminal's versatility.

  19. 40 CFR 30.61 - Termination.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    .... (2) By EPA with the consent of the recipient, in which case the two parties shall agree upon the termination conditions, including the effective date and, in the case of partial termination, the portion to... reasons for such termination, the effective date, and, in the case of partial termination, the portion...

  20. 15 CFR 14.61 - Termination.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... with the consent of the recipient, in which case the two parties shall agree upon the termination conditions, including the effective date and, in the case of partial termination, the portion to be... reasons for such termination, the effective date, and, in the case of partial termination, the portion...

  1. 38 CFR 49.61 - Termination.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... conditions of an award. (2) By the Federal awarding agency with the consent of the recipient, in which case... case of partial termination, the portion to be terminated. (3) By the recipient upon sending to the... date, and, in the case of partial termination, the portion to be terminated. However, if the...

  2. Combinatorial metabolic engineering of Saccharomyces cerevisiae for terminal alkene production.

    PubMed

    Chen, Binbin; Lee, Dong-Yup; Chang, Matthew Wook

    2015-09-01

    Biological production of terminal alkenes has garnered a significant interest due to their industrial applications such as lubricants, detergents and fuels. Here, we engineered the yeast Saccharomyces cerevisiae to produce terminal alkenes via a one-step fatty acid decarboxylation pathway and improved the alkene production using combinatorial engineering strategies. In brief, we first characterized eight fatty acid decarboxylases to enable and enhance alkene production. We then increased the production titer 7-fold by improving the availability of the precursor fatty acids. We additionally increased the titer about 5-fold through genetic cofactor engineering and gene expression tuning in rich medium. Lastly, we further improved the titer 1.8-fold to 3.7 mg/L by optimizing the culturing conditions in bioreactors. This study represents the first report of terminal alkene biosynthesis in S. cerevisiae, and the abovementioned combinatorial engineering approaches collectively increased the titer 67.4-fold. We envision that these approaches could provide insights into devising engineering strategies to improve the production of fatty acid-derived biochemicals in S. cerevisiae.

  3. Novel terminal strips for transformers

    NASA Technical Reports Server (NTRS)

    Wiler, E. M.

    1969-01-01

    Spacing tinned terminal leads between two tapes of woven glass fiber that are sandwich-bonded with pliable epoxy adhesive alleviates problems of taped leads pulling away from the transformer and shorting due to crossover of wires. Individual leads may or may not be enclosed in glass-fiber sleeves.

  4. Balanced Branching in Transcription Termination

    NASA Technical Reports Server (NTRS)

    Harrington, K. J.; Laughlin, R. B.; Liang, S.

    2000-01-01

    The theory of stochastic transcription termination based on free-energy competition [von Hippel, P. H. & Yager, T. D. (1992) Science 255,809-812 and van Hippel, P. H. & Yager, T. D. (1991) Proc. Natl. Acad. Sci. USA 88, 2307-2311] requires two or more reaction rates to be delicately balanced over a wide range of physical conditions. A large body of work on glasses and large molecules suggests that this balancing should be impossible in such a large system in the absence of a new organizing principle of matter. We review the experimental literature of termination and find no evidence for such a principle, but do find many troubling Inconsistencies, most notably, anomalous memory effects. These effects suggest that termination has a deterministic component and may conceivably not be stochastic at all. We find that a key experiment by Wilson and von Hippel [Wilson, K. S. & von Hippel, P. H. (1994) J. Mol. Biol. 244,36-51] thought to demonstrate stochastic termination was an incorrectly analyzed regulatory effect of Mg(2+) binding.

  5. Do Twelfths Terminate or Repeat?

    ERIC Educational Resources Information Center

    Ambrose, Rebecca; Burnison, Erica

    2015-01-01

    When finding the decimal equivalent of a fraction with 12 in the denominator, will it terminate or repeat? This question came from a seventh grader in author Erica Burnison's class as the student was pondering a poster generated by one of her classmates. Not only was the question intriguing, but it also affirmed the belief in the power of…

  6. Teaching the Terminally Ill Child.

    ERIC Educational Resources Information Center

    Ainsa, Trisha

    1981-01-01

    Classroom teachers of terminally ill children face potentially difficult, challenging, rewarding and professionally expanding experiences which require an understanding of the basic needs of the dying. Strategies for teaching such children include literature, writing, role playing, magic circle discussions, play therapy, art therapy, counseling,…

  7. Video Display Terminals: Radiation Issues.

    ERIC Educational Resources Information Center

    Murray, William E.

    1985-01-01

    Discusses information gathered in past few years related to health effects of video display terminals (VDTs) with particular emphasis given to issues raised by VDT users. Topics covered include radiation emissions, health concerns, radiation surveys, occupational radiation exposure standards, and long-term risks. (17 references) (EJS)

  8. Progrès récents dans l'utilisation de la Chromatographie Gazeuse Inverse pour la détermination des propriétés acide-base des surfaces solides

    NASA Astrophysics Data System (ADS)

    Papirer, E.; Brendlé, E.

    1998-01-01

    Inverse Gas Chromatography (IGC) is a method well suited for the study of divided solids, but also of fibres. In this paper, the principles of IGC, its advantages such as ease and rapidity of measurement, but also limitations due essentially to the energetic heterogeneity of the solid surfaces are discussed. Finally, a new procedure allowing to estimate the acidity and basicity of the surface involving topology concepts of the molecules used to probe the surface is presented. Experimental results of the Laboratory, but also results extracted from the literature concerning silica, titanium dioxide, poly(methyl methacrylate) and poly(ethylene) fibers, are taken to verify the proposed method. La chromatographie Gazeuse Inverse (CGI) s'avère comme une méthode de choix pour l'étude des solides divisés, mais aussi de fibres. Après avoir rappelé quelques principes de base de la CGI, les avantages de la méthode comme la facilité de mise en oeuvre, sa rapidité..., nous soulignerons ses limites qui sont essentiellement à attribuer à l'hétérogénéité énergétique des surfaces solides. Finalement, nous décrirons une nouvelle approche de l'acidité et de la basicité de surface grâce à l'utilisation des concepts de topologie des molécules employées pour sonder la surface. Des résultats expérimentaux obtenus au Laboratoire, mais aussi tirés de la littérature et concernant la silice, l'oxyde de titane, la poly(méthacrylate de méthyle) et les fibres de poly(éthylène), permettent d'illustrer la pertinence de la méthode proposée.

  9. Clothes Dryer Automatic Termination Evaluation

    SciTech Connect

    TeGrotenhuis, Ward E.

    2014-10-01

    Volume 2: Improved Sensor and Control Designs Many residential clothes dryers on the market today provide automatic cycles that are intended to stop when the clothes are dry, as determined by the final remaining moisture content (RMC). However, testing of automatic termination cycles has shown that many dryers are susceptible to over-drying of loads, leading to excess energy consumption. In particular, tests performed using the DOE Test Procedure in Appendix D2 of 10 CFR 430 subpart B have shown that as much as 62% of the energy used in a cycle may be from over-drying. Volume 1 of this report shows an average of 20% excess energy from over-drying when running automatic cycles with various load compositions and dryer settings. Consequently, improving automatic termination sensors and algorithms has the potential for substantial energy savings in the U.S.

  10. VSATs - Very small aperture terminals

    NASA Astrophysics Data System (ADS)

    Everett, John L.

    The present volume on very small aperture terminals (VSATs) discusses antennas, semiconductor devices, and traveling wave tubes and amplifiers for VSAT systems, VSAT low noise downconverters, and modems and codecs for VSAT systems. Attention is given to multiaccess protocols for VSAT networks, protocol software in Ku-band VSAT network systems, system design of VSAT data networks, and the policing of VSAT networks. Topics addressed include the PANDATA and PolyCom systems, APOLLO - a satellite-based information distribution system, data broadcasting within a satellite television channel, and the NEC NEXTAR VSAT system. Also discussed are small aperture military ground terminals, link budgets for VSAT systems, capabilities and experience of a VSAT service provider, and developments in VSAT regulation.

  11. MEANS FOR TERMINATING NUCLEAR REACTIONS

    DOEpatents

    Cooper, C.M.

    1959-02-17

    An apparatus is presented for use in a reactor of the heterogeneous, fluid cooled type for the purpose of quickly terminating the reaction, the coolant being circulated through coolant tubes extending through the reactor core. Several of the tubes in the critical region are connected through valves to a tank containing a poisoning fluid having a high neutron capture crosssection and to a reservoir. When it is desired to quickly terminate the reaction, the valves are operated to permit the flow of the poisoning fluid through these particular tubes and into the reservoir while normal coolant is being circulated through the remaining tubes. The apparatus is designed to prevent contamination of the primary coolant by the poisoning fluid.

  12. Design of superlattice termination layers

    NASA Technical Reports Server (NTRS)

    Coon, D. D.; Sorar, E.

    1990-01-01

    Problems associated with quantum mechanical reflection of miniband carriers at the ends of superlattices are examined. Moebius transformations which map miniband Bloch wave reflectivity into plane wave reflectivity and vice versa are derived. These transformations facilitate the design of blocking and antiblocking layers which are analogous to reflective and antireflective coatings on optical elements. An example of termination layer design which is easy to implement is given. Applications include superlattice infrared detector design.

  13. Military Governance and War Termination

    DTIC Science & Technology

    2011-05-19

    existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments...amount of census data was collected, which served civil administration purposes and provided intelligence for military operations.123 Additionally, in...York: Henry Holt and Company, 2005. Bade , Bruce C. War Termination: Why Don’t We Plan It? Fort McNair: National War College, 1994. Barthlomees, J

  14. Enhanced Thermal Stability of Polylactide by Terminal Conjugation Groups

    NASA Astrophysics Data System (ADS)

    Tran, Hang Thi; Matsusaki, Michiya; Akashi, Mitsuru; Vu, Ngo Dinh

    2016-05-01

    Various acids such as aliphatic or carbocyclic fatty or aromatic acids were successfully conjugated into the ending hydroxyl group of poly( l-lactide) (PLLA). The chemical structures of various acid-PLLAs were confirmed by Fourier transform infrared and proton nuclear magnetic resonance analysis. The crystallinity and solubility of the original PLLA were maintained after the terminal conjugation of various acids. The thermal properties were significantly improved, especially the 10% weight-loss temperature that showed an increase of over 80°C for conjugation of aliphatic or aromatic acids as compared to that of the corresponding original PLLA. In addition, more than 60 wt.% of the aliphatic acid-PLLAs was pyrolyzed, and aromatic acid-PLLAs degraded only about 10 wt.% for 150 min, although the original PLLA was pyrolyzed completely at 250°C for 7 min. The thermal stability of PLLA was controlled by the conjugation of aliphatic or aromatic acids into a chain end. These acid-PLLAs may be useful as materials with high thermal stability for various application fields.

  15. High Octane Fuel: Terminal Backgrounder

    SciTech Connect

    Moriarty, Kristi

    2016-02-11

    The Bioenergy Technologies Office of the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy sponsored a scoping study to assess the potential of ethanol-based high octane fuel (HOF) to reduce energy consumption and greenhouse gas emissions. When the HOF blend is made with 25%-40% ethanol by volume, this energy efficiency improvement is potentially sufficient to offset the reduced vehicle range often associated with the decreased volumetric energy density of ethanol. The purpose of this study is to assess the ability of the fuel supply chain to accommodate more ethanol at fuel terminals. Fuel terminals are midstream in the transportation fuel supply chain and serve to store and distribute fuels to end users. While there are no technical issues to storing more ethanol at fuel terminals, there are several factors that could impact the ability to deploy more ethanol. The most significant of these issues include the availability of land to add more infrastructure and accommodate more truck traffic for ethanol deliveries as well as a lengthy permitting process to erect more tanks.

  16. Hydrogen at the Lunar Terminator

    NASA Astrophysics Data System (ADS)

    Livengood, T. A.; Chin, G.; Sagdeev, R. Z.; Mitrofanov, I. G.; Boynton, W. V.; Evans, L. G.; Litvak, M. L.; McClanahan, T. P.; Sanin, A. B.; Starr, R. D.; Su, J. J.

    2015-10-01

    Suppression of the Moon's naturally occurring epithermal neutron leakage flux near the equatorial dawn terminator is consistent with the presence of diurnally varying quantities of hydrogen in the regolith with maximum concentration on the day side of the dawn terminator. This flux suppression has been observed using the Lunar Exploration Neutron Detector (LEND) on the polar-orbiting Lunar Reconnaissance Orbiter (LRO). The chemical form of hydrogen is not determined, but other remote sensing methods and elemental availability suggest water. The observed variability is interpreted as frost collecting in or on the cold nightside surface, thermally desorbing in sunlight during the lunar morning,and migrating away from the warm subsolar region across the nearby terminator to return to the lunar surface. The maximum concentration, averaged over the upper ~1m of regolith to which neutron detection is sensitive,is estimated to be 0.0125±0.0022 weight-percent water-equivalent hydrogen (wt% WEH), yielding an accumulation of 190±30 ml recoverable water per square meter of regolith at each dawn. The source of hydrogen (water) must be in equilibrium with losses due to solar photolysis and escape. A chemical recycling process or self-shielding from solar UV must be assumed in order to bring the loss rate down to compatibility with possible sources, including solar wind or micrometeoroid delivery of hydrogen, which require near-complete retention of hydrogen,or outgassing of primordial volatiles, for which a plausible supply rate requires significantly less retention efficiency.

  17. The GRO remote terminal system

    NASA Technical Reports Server (NTRS)

    Zillig, David J.; Valvano, Joe

    1994-01-01

    In March 1992, NASA HQ challenged GSFC/Code 531 to propose a fast, low-cost approach to close the Tracking Data Relay Satellite System (TDRSS) Zone-of-Exclusion (ZOE) over the Indian Ocean in order to provide global communications coverage for the Compton Gamma Ray Observatory (GRO) spacecraft. GRO had lost its tape recording capability which limited its valuable science data return to real-time contacts with the TDRS-E and TDRS-W synchronous data relay satellites, yielding only approximately 62 percent of the possible data obtainable. To achieve global coverage, a TDRS spacecraft would have to be moved over the Indian Ocean out of line-of-sight control of White Sands Ground Terminal (WSGT). To minimize operations life cycle costs, Headquarters also set a goal for remote control, from the WSGT, of the overseas ground station which was required for direct communications with TDRS-1. On August 27, 1992, Code 531 was given the go ahead to implement the proposed GRO Relay Terminal System (GRTS). This paper describes the Remote Ground Relay Terminal (RGRT) which went operational at the Canberra Deep Space Communications Complex (CDSCC) in Canberra, Australia in December 1993 and is currently augmenting the TDRSS constellation in returning between 80-100 percent of GRO science data under the control of a single operator at WSGT.

  18. 42 CFR 460.54 - Termination procedures.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... (CONTINUED) PROGRAMS OF ALL-INCLUSIVE CARE FOR THE ELDERLY (PACE) PROGRAMS OF ALL-INCLUSIVE CARE FOR THE ELDERLY (PACE) Sanctions, Enforcement Actions, and Termination § 460.54 Termination procedures. (a)...

  19. 42 CFR 460.54 - Termination procedures.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... (CONTINUED) PROGRAMS OF ALL-INCLUSIVE CARE FOR THE ELDERLY (PACE) PROGRAMS OF ALL-INCLUSIVE CARE FOR THE ELDERLY (PACE) Sanctions, Enforcement Actions, and Termination § 460.54 Termination procedures. (a)...

  20. 42 CFR 460.54 - Termination procedures.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... (CONTINUED) PROGRAMS OF ALL-INCLUSIVE CARE FOR THE ELDERLY (PACE) PROGRAMS OF ALL-INCLUSIVE CARE FOR THE ELDERLY (PACE) Sanctions, Enforcement Actions, and Termination § 460.54 Termination procedures. (a)...

  1. 42 CFR 460.54 - Termination procedures.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... (CONTINUED) PROGRAMS OF ALL-INCLUSIVE CARE FOR THE ELDERLY (PACE) PROGRAMS OF ALL-INCLUSIVE CARE FOR THE ELDERLY (PACE) Sanctions, Enforcement Actions, and Termination § 460.54 Termination procedures. (a)...

  2. 42 CFR 460.54 - Termination procedures.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... (CONTINUED) PROGRAMS OF ALL-INCLUSIVE CARE FOR THE ELDERLY (PACE) PROGRAMS OF ALL-INCLUSIVE CARE FOR THE ELDERLY (PACE) Sanctions, Enforcement Actions, and Termination § 460.54 Termination procedures. (a)...

  3. 48 CFR 12.403 - Termination.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... entitled “Termination for the Government's Convenience” and “Termination for Cause” contain concepts which... required to comply with the cost accounting standards or the contract cost principles in part 31....

  4. Ethynyl terminated imidothioethers and resins therefrom

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M. (Inventor); Connell, John W. (Inventor); Bass, R. Gerald (Inventor)

    1989-01-01

    Ethynyl terminated imidothioethers (ETIs) are prepared by the reaction of a dimercaptan, such as 4,4'-dimercaptodiphenyl ether, and an ethynyl containing maleimide, such as N-(3-ethynylphenyl)maleimide. Blends of thse ETIs and ethynyl terminated polymeric materials, such as ethynyl terminated sulfones and ethynyl terminated arylene ethers, are also prepared. These resin blends exhibit excellent processability, and the cured blends show excellent fracture toughness and solvent resistance, as well as excellent adhesive and composite properties.

  5. Ethynyl terminated imidothioethers and resins therefrom

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M. (Inventor); Connell, John W. (Inventor); Bass, R. Gerald (Inventor)

    1991-01-01

    Ethynyl terminated imidothioethers (ETIs) are prepared by the reaction of a dimercaptan, such as 4,4'-dimercaptodiphenyl ether, and an ethynyl containing maleimide, such as N-(3-ethynylphenyl)maleimide. Blends of these ETIs and ethynyl terminated polymeric materials, such as ethynyl terminated sulfones and ethynyl terminated arylene ethers, are also prepared. These resin blends exhibit excellent processability, and the cured blends show excellent fracture toughness and solvent resistance, as well as excellent adhesive and composite properties.

  6. 49 CFR 374.309 - Terminal facilities.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false Terminal facilities. 374.309 Section 374.309... REGULATIONS Adequacy of Intercity Motor Common Carrier Passenger Service § 374.309 Terminal facilities. (a... attendants and be regularly patrolled. (b) Outside facilities. At terminals and stations that are closed...

  7. 30 CFR 745.15 - Termination.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... PROGRAM STATE-FEDERAL COOPERATIVE AGREEMENTS § 745.15 Termination. (a) A cooperative agreement may be terminated by the State upon written notice to the Secretary, specifying the date upon which the cooperative... notice. (b) A cooperative agreement may be terminated by the Secretary after giving notice to the...

  8. 33 CFR 159.79 - Terminals.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Terminals. 159.79 Section 159.79 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.79 Terminals. Terminals must be solderless...

  9. 33 CFR 159.79 - Terminals.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Terminals. 159.79 Section 159.79 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.79 Terminals. Terminals must be solderless...

  10. 33 CFR 159.79 - Terminals.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Terminals. 159.79 Section 159.79 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.79 Terminals. Terminals must be solderless...

  11. 12 CFR 1102.7 - Waiver termination.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 9 2012-01-01 2012-01-01 false Waiver termination. 1102.7 Section 1102.7 Banks and Banking FEDERAL FINANCIAL INSTITUTIONS EXAMINATION COUNCIL APPRAISER REGULATION Temporary Waiver Requests § 1102.7 Waiver termination. The ASC at any time may terminate a waiver order on the finding...

  12. 45 CFR 74.61 - Termination.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... conditions of an award. (2) By the HHS awarding agency with the consent of the recipient, in which case the two parties shall agree upon the termination conditions, including the effective date and, in the case..., and, in the case of partial termination, the portion to be terminated. However, if the HHS...

  13. 77 FR 21981 - Maher Terminal, LLC

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-12

    ... Maher Terminal, LLC v. The Port Authority of New York and New Jersey; Notice of Filing of Complaint and...'' by Maher Terminal, LLC, hereinafter ``Complainant'' against the Port Authority of New York and New..., New York; owns marine terminal facilities in the New York New Jersey area, including in Elizabeth,...

  14. 10 CFR 436.38 - Terminating contracts.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 3 2014-01-01 2014-01-01 false Terminating contracts. 436.38 Section 436.38 Energy... Procedures for Energy Savings Performance Contracting § 436.38 Terminating contracts. (a) Except as otherwise provided by this subpart, termination of energy savings performance contracts shall be subject to...

  15. 50 CFR 14.110 - Terminal facilities.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 1 2010-10-01 2010-10-01 false Terminal facilities. 14.110 Section 14.110..., POSSESSION, TRANSPORTATION, SALE, PURCHASE, BARTER, EXPORTATION, AND IMPORTATION OF WILDLIFE AND PLANTS... Wild Mammals and Birds to the United States § 14.110 Terminal facilities. (a) Any terminal...

  16. 45 CFR 1206.1-5 - Termination.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 4 2011-10-01 2011-10-01 false Termination. 1206.1-5 Section 1206.1-5 Public Welfare Regulations Relating to Public Welfare (Continued) CORPORATION FOR NATIONAL AND COMMUNITY SERVICE GRANTS AND CONTRACTS-SUSPENSION AND TERMINATION AND DENIAL OF APPLICATION FOR REFUNDING Suspension and Termination of Assistance §...

  17. 46 CFR 525.2 - Terminal schedules.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... MARITIME COMMISSION REGULATIONS AFFECTING OCEAN SHIPPING IN FOREIGN COMMERCE MARINE TERMINAL OPERATOR... their own negligence, or that impose upon others the obligation to indemnify or hold-harmless the terminals from liability for their own negligence. (2) Enforcement of terminal schedules. Any schedule...

  18. 46 CFR 525.2 - Terminal schedules.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... MARITIME COMMISSION REGULATIONS AFFECTING OCEAN SHIPPING IN FOREIGN COMMERCE MARINE TERMINAL OPERATOR... their own negligence, or that impose upon others the obligation to indemnify or hold-harmless the terminals from liability for their own negligence. (2) Enforcement of terminal schedules. Any schedule...

  19. 46 CFR 525.2 - Terminal schedules.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... MARITIME COMMISSION REGULATIONS AFFECTING OCEAN SHIPPING IN FOREIGN COMMERCE MARINE TERMINAL OPERATOR... their own negligence, or that impose upon others the obligation to indemnify or hold-harmless the terminals from liability for their own negligence. (2) Enforcement of terminal schedules. Any schedule...

  20. 46 CFR 525.2 - Terminal schedules.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... MARITIME COMMISSION REGULATIONS AFFECTING OCEAN SHIPPING IN FOREIGN COMMERCE MARINE TERMINAL OPERATOR... their own negligence, or that impose upon others the obligation to indemnify or hold-harmless the terminals from liability for their own negligence. (2) Enforcement of terminal schedules. Any schedule...

  1. 33 CFR 159.79 - Terminals.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Terminals. 159.79 Section 159.79 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.79 Terminals. Terminals must be solderless...

  2. 33 CFR 159.79 - Terminals.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Terminals. 159.79 Section 159.79 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.79 Terminals. Terminals must be solderless...

  3. 42 CFR 66.109 - Termination.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Termination. 66.109 Section 66.109 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES FELLOWSHIPS, INTERNSHIPS, TRAINING NATIONAL RESEARCH SERVICE AWARDS Direct Awards § 66.109 Termination. (a) The Secretary may terminate...

  4. 42 CFR 66.109 - Termination.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Termination. 66.109 Section 66.109 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES FELLOWSHIPS, INTERNSHIPS, TRAINING NATIONAL RESEARCH SERVICE AWARDS Direct Awards § 66.109 Termination. (a) The Secretary may terminate...

  5. 42 CFR 66.109 - Termination.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Termination. 66.109 Section 66.109 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES FELLOWSHIPS, INTERNSHIPS, TRAINING NATIONAL RESEARCH SERVICE AWARDS Direct Awards § 66.109 Termination. (a) The Secretary may terminate...

  6. 42 CFR 66.109 - Termination.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Termination. 66.109 Section 66.109 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES FELLOWSHIPS, INTERNSHIPS, TRAINING NATIONAL RESEARCH SERVICE AWARDS Direct Awards § 66.109 Termination. (a) The Secretary may terminate...

  7. 42 CFR 66.109 - Termination.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Termination. 66.109 Section 66.109 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES FELLOWSHIPS, INTERNSHIPS, TRAINING NATIONAL RESEARCH SERVICE AWARDS Direct Awards § 66.109 Termination. (a) The Secretary may terminate...

  8. Protein splicing of inteins with atypical glutamine and aspartate C-terminal residues.

    PubMed

    Amitai, Gil; Dassa, Bareket; Pietrokovski, Shmuel

    2004-01-30

    Inteins are protein-splicing domains present in many proteins. They self-catalyze their excision from the host protein, ligating their former flanks by a peptide bond. The C-terminal residue of inteins is typically an asparagine (Asn). Cyclization of this residue to succinimide causes the final detachment of inteins from their hosts. We studied protein-splicing activity of two inteins with atypical C-terminal residues. One having a C-terminal glutamine (Gln), isolated from Chilo iridescent virus (CIV), and another unique intein, first reported here, with a C-terminal aspartate, isolated from Carboxydothermus hydrogenoformans (Chy). Protein-splicing activity was examined in the wild-type inteins and in several mutants with N- and C-terminal amino acid substitutions. We demonstrate that both wild-type inteins can protein splice, probably by new variations of the typical protein-splicing mechanism. Substituting the atypical C-terminal residue to the typical Asn retained protein-splicing only in the CIV intein. All diverse C-terminal substitutions in the Chy intein (Asp(345) to Asn, Gln, Glu, and Ala) abolished protein-splicing and generated N- and C-terminal cleavage. The observed C-terminal cleavage in the Chy intein ending with Ala cannot be explained by cyclization of this residue. We present and discuss several new models for reactions in the protein-splicing pathway.

  9. A palladium-catalyzed three-component-coupling strategy for the differential vicinal diarylation of terminal 1,3-dienes.

    PubMed

    Stokes, Benjamin J; Liao, Longyan; de Andrade, Aline Mendes; Wang, Qiaofeng; Sigman, Matthew S

    2014-09-05

    A palladium-catalyzed intermolecular vicinal diarylation of terminal 1,3-dienes using aryldiazonium tetrafluoroborates and arylboronic acids is reported. Using this technology, two different arenes are regioselectively introduced in a vicinal fashion across the terminal alkene of a variety of terminal 1,3-dienes at ambient temperature. Through the action of a chiral bicyclo[2.2.2]octadienyl ligand at -20 °C, good enantioselectivity has also been achieved.

  10. Automated carboxy-terminal sequence analysis of peptides and proteins using diphenyl phosphoroisothiocyanatidate.

    PubMed Central

    Bailey, J. M.; Nikfarjam, F.; Shenoy, N. R.; Shively, J. E.

    1992-01-01

    Proteins and peptides can be sequenced from the carboxy-terminus with isothiocyanate reagents to produce amino acid thiohydantoin derivatives. Previous studies in our laboratory have focused on the automation of the thiocyanate chemistry using acetic anhydride and trimethylsilylisothiocyanate (TMS-ITC) to derivatize the C-terminal amino acid to a thiohydantoin and sodium trimethylsilanolate for specific hydrolysis of the derivatized C-terminal amino acid (Bailey, J.M., Shenoy, N.R., Ronk, M., & Shively, J.E., 1992, Protein Sci. 1, 68-80). A major limitation of this approach was the need to activate the C-terminus with acetic anhydride. We now describe the use of a new reagent, diphenyl phosphoroisothiocyanatidate (DPP-ITC) and pyridine, which combines the activation and derivatization steps to produce peptidylthiohydantoins. Previous work by Kenner et al. (Kenner, G.W., Khorana, H.G., & Stedman, R.J., 1953, Chem. Soc. J., 673-678) with this reagent demonstrated slow kinetics. Several days were required for complete reaction. We show here that the inclusion of pyridine was found to promote the formation of C-terminal thiohydantoins by DPP-ITC resulting in complete conversion of the C-terminal amino acid to a thiohydantoin in less than 1 h. Reagents such as imidazole, triazine, and tetrazole were also found to promote the reaction with DPP-ITC as effectively as pyridine. General base catalysts, such as triethylamine, do not promote the reaction, but are required to convert the C-terminal carboxylic acid to a salt prior to the reaction with DPP-ITC and pyridine. By introducing the DPP-ITC reagent and pyridine in separate steps in an automated sequencer, we observed improved sequencing yields for amino acids normally found difficult to derivatize with acetic anhydride/TMS-ITC. This was particularly true for aspartic acid, which now can be sequenced in yields comparable to most of the other amino acids. Automated programs are described for the C-terminal sequencing of

  11. 26 CFR 1.411(d)-2 - Termination or partial termination; discontinuance of contributions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Bonus Plans, Etc. § 1.411(d)-2 Termination or partial termination; discontinuance of contributions. (a... such plan is not a qualified trust) unless the plan provides that— (i) Upon the termination or partial... partial termination of the plan (or, in the case of a plan to which section 412 does not apply, upon...

  12. 12 CFR 327.6 - Terminating transfers; other terminations of insurance

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... at the terminating institution's rate. (b) Assessment for quarter in which the terminating transfer... remaining after the terminating transfer and calculated at the acquiring institution's rate and using the... assessment rate, and the terminating institution shall not be assessed separately for that quarter. (c)...

  13. N-Terminal Methionine Processing.

    PubMed

    Wingfield, Paul T

    2017-04-03

    Protein synthesis is initiated by methionine in eukaryotes and by formylmethionine in prokaryotes. N-terminal methionine can be co-translationally cleaved by the enzyme methionine aminopeptidase (MAP). When recombinant proteins are expressed in bacterial and mammalian expression systems, there is a simple universal rule that predicts whether the initiating methionine will be processed by MAP based on the size of the residue adjacent (penultimate) to the N-methionine. In general, if the side chains of the penultimate residues have a radius of gyration of 1.29 Å or less, methionine is cleaved. © 2017 by John Wiley & Sons, Inc.

  14. MSAT aeronautical mobile satellite communications terminal development

    NASA Technical Reports Server (NTRS)

    Sutherland, C. A.; Sydor, J. T.

    1995-01-01

    CAL has undertaken the development of a new aeronautical mobile terminal for the North American MSAT market. The terminal is to meet the MSAT standard and is aimed in particular at the 300,000 general aviation and business aircraft in North America. The terminals are therefore relatively low cost and small in size when compared to those currently being produced for larger airline aircraft. The terminal incorporates a top mounted mechanical steered antenna and a unique antenna steering subsystem. An overview of the terminal design is presented.

  15. Network load of X terminals at CDF

    SciTech Connect

    Abar, F.; O`Reilly, C.; Wicklund, E.

    1992-03-01

    As an aid to planning future usage of X terminals, the authors measured the network bandwidth used by X terminals on a single Ethernet in a typical application environment at Fermilab. The objectives were twofold. The first objective was to identify the impact of adding one more X terminal onto the CDF Ethernet . The second objective was to determine the maximum number of X terminals allowable on the CDF network. The findings reveal that an X terminal in this environment used, on average, 431 + /{minus}45 bytes/second. This is quite small compared to the utilizable bandwidth of the thinwire Ethernet network (375 Kilobytes/second, equivalent to 30% of total bandwidth). This amounts to an averaged load of .034% on the network per X terminal. This paper addresses the network load solely. It does not address the loads imposed by X terminals on the memory and CPU of the host systems.

  16. N-terminal modification of proteins with o-aminophenols.

    PubMed

    Obermeyer, Allie C; Jarman, John B; Francis, Matthew B

    2014-07-09

    The synthetic modification of proteins plays an important role in chemical biology and biomaterials science. These fields provide a constant need for chemical tools that can introduce new functionality in specific locations on protein surfaces. In this work, an oxidative strategy is demonstrated for the efficient modification of N-terminal residues on peptides and N-terminal proline residues on proteins. The strategy uses o-aminophenols or o-catechols that are oxidized to active coupling species in situ using potassium ferricyanide. Peptide screening results have revealed that many N-terminal amino acids can participate in this reaction, and that proline residues are particularly reactive. When applied to protein substrates, the reaction shows a stronger requirement for the proline group. Key advantages of the reaction include its fast second-order kinetics and ability to achieve site-selective modification in a single step using low concentrations of reagent. Although free cysteines are also modified by the coupling reaction, they can be protected through disulfide formation and then liberated after N-terminal coupling is complete. This allows access to doubly functionalized bioconjugates that can be difficult to access using other methods.

  17. Transcription termination maintains chromosome integrity.

    PubMed

    Washburn, Robert S; Gottesman, Max E

    2011-01-11

    DNA replication fork movement is impeded by collisions with transcription elongation complexes (TEC). We propose that a critical function of transcription termination factors is to prevent TEC from blocking DNA replication and inducing replication fork arrest, one consequence of which is DNA double-strand breaks. We show that inhibition of Rho-dependent transcription termination by bicyclomycin in Escherichia coli induced double-strand breaks. Cells deleted for Rho-cofactors nusA and nusG were hypersensitive to bicyclomycin, and had extensive chromosome fragmentation even in the absence of the drug. An RNA polymerase mutation that destabilizes TEC (rpoB*35) increased bicyclomycin resistance >40-fold. Double-strand break formation depended on DNA replication, and can be explained by replication fork collapse. Deleting recombination genes required for replication fork repair (recB and ruvC) increased sensitivity to bicyclomycin, as did loss of the replication fork reloading helicases rep and priA. We propose that Rho responds to a translocating replisome by releasing obstructing TEC.

  18. Nickel-Catalyzed Stereoselective Alkenylation of C(sp(3))-H Bonds with Terminal Alkynes.

    PubMed

    Lin, Cong; Chen, Zhengkai; Liu, Zhanxiang; Zhang, Yuhong

    2017-02-17

    A nickel-catalyzed stereoselective alkenylation of an unactivated β-C(sp(3))-H bond in aliphatic amide with terminal alkynes using 8-aminoquinoline auxiliary is reported for the first time. This reaction displays excellent functional group tolerance with respect to both aliphatic amides and terminal alkynes and features a cheap nickel catalytic system. The 8-aminoquinolyl directing group could be smoothly removed, and the resultant β-styrylcarboxylic acid derivatives could serve as versatile building blocks for further transformation.

  19. N-terminal sequence analysis of proteins and peptides.

    PubMed

    Reim, D F; Speicher, D W

    2001-05-01

    Amino-terminal (N-terminal) sequence analysis is used to identify the order of amino acids of proteins or peptides, starting at their N-terminal end. This unit describes the sequence analysis of protein or peptide samples in solution or bound to PVDF membranes using a Perkin-Elmer Procise Sequencer. Sequence analysis of protein or peptide samples in solution or bound to PVDF membranes using a Hewlett-Packard Model G1005A sequencer is also described. Methods are provided for optimizing separation of PTH amino acid derivatives on Perkin-Elmer instruments and for increasing the proportion of sample injected onto the PTH analyzer on older Perkin-Elmer instruments by installing a modified sample loop. The amount of data obtained from a single sequencer run is substantial, and careful interpretation of this data by an experienced scientist familiar with the current operation performance of the instrument used for this analysis is critically important. A discussion of data interpretation is therefore provided. Finally, discussion of optimization of sequencer performance as well as possible solutions to frequently encountered problems is included.

  20. Effects of sterilization on optical and mechanical reliability of specialty optical fibers and terminations

    NASA Astrophysics Data System (ADS)

    Stolov, Andrei A.; Warych, Edward T.; Smith, William P.; Fournier, Paula L.; Hokansson, Adam S.; Li, Jie; Allen, R. Steve

    2014-02-01

    Optical fibers and terminations were subjected to different sterilization techniques, including multiple autoclaving and treatments with peracetic acid, E-beam and UV radiation. Effects of different sterilization techniques on key optical and mechanical properties of the fibers and the terminations were revealed. The primary attention was given to behavior of the coatings on the fibers and adhesives used in the terminations in harsh sterilization environments. The optical fibers with following four coating/buffer types were investigated: (i) dual acrylate, (ii) polyimide, (iii) silicone/PEEK and (iv) fluoroacrylate hard cladding/ETFE.

  1. Design of petroleum products terminal wastewater systems

    SciTech Connect

    Klock, B.

    1995-12-31

    Petroleum products terminals, used in conjunction with transportation operations to accomplish the flow of products from their source in refineries down to the consumers, are relatively simple facilities comprising product storage, the means for connecting storage to transportation operations, and other operations to support those functions. Although wastewater generation at terminals is relatively minor, increasingly strict regulation of wastewater from even minor sources is making it more critical that terminal wastewater handling, treatment, and disposal be understood and optimized to ensure that effective wastewater treatment is accomplished at reasonable cost. Anticipating the increased demands on terminal wastewater handling, the API Marketing Terminal Effluent Task Force has sponsored a number of studies to characterize wastewater at terminals and to develop practical means for treating the water. In addition, the Task Force sponsored Texaco`s writing of the report on which this paper is based, API 4602, Minimization, Handling, Treatment, and Disposal of Petroleum Products Terminal Wastewaters. This paper highlights some of the key recommendations in the report, which are: (1) begin characterizing the terminal`s tank bottoms water flow and quality as soon as possible; (2) determine the optimum wastewater disposal option; (3) for most situations, segregate stormwater from contaminated water; (4) if wastewater is treated, use a collection tank to equalize the flow and concentration of tank bottoms water; (5) if wastewater is hauled off to a disposal company, consider removing benzene first; and (6) minimize the use of detergents in the terminal.

  2. Does oral experience terminate ingestion?

    PubMed

    Swithers, S E; Hall, W G

    1994-10-01

    Using data from studies of ingestive behavior in developing rat pups we demonstrate how oral experience can contribute to the termination of ingestion. In rat pups, repeated oral stimulation with sweet solutions causes a decline in oral responsiveness. The diminished responsiveness is specific to the flavor of the stimulus experienced orally and can persist for several hours. We suggest that this experience-based decrement in responsiveness is best considered "oral habituation" and that oral habituation largely accounts for the onset of satiety. Post-ingestive feedback signals may have their influence through the oral habituation process or act in the context of oral habituation. Oral habituation is also shown to depend on the pattern of stimulus presentation, a phenomenon that adds considerable complexity to assessing the contributions of oral experience to satiety. The concept of oral habituation may be useful in understanding the immediate control of ingestion and the moment-to-moment expression of ingestive behavior in adult animals.

  3. Two terminal micropower radar sensor

    DOEpatents

    McEwan, Thomas E.

    1995-01-01

    A simple, low power ultra-wideband radar motion sensor/switch configuration connects a power source and load to ground. The switch is connected to and controlled by the signal output of a radar motion sensor. The power input of the motion sensor is connected to the load through a diode which conducts power to the motion sensor when the switch is open. A storage capacitor or rechargeable battery is connected to the power input of the motion sensor. The storage capacitor or battery is charged when the switch is open and powers the motion sensor when the switch is closed. The motion sensor and switch are connected between the same two terminals between the source/load and ground.

  4. Two terminal micropower radar sensor

    DOEpatents

    McEwan, T.E.

    1995-11-07

    A simple, low power ultra-wideband radar motion sensor/switch configuration connects a power source and load to ground. The switch is connected to and controlled by the signal output of a radar motion sensor. The power input of the motion sensor is connected to the load through a diode which conducts power to the motion sensor when the switch is open. A storage capacitor or rechargeable battery is connected to the power input of the motion sensor. The storage capacitor or battery is charged when the switch is open and powers the motion sensor when the switch is closed. The motion sensor and switch are connected between the same two terminals between the source/load and ground. 3 figs.

  5. Transcription termination by nuclear RNA polymerases

    PubMed Central

    Richard, Patricia; Manley, James L.

    2009-01-01

    Gene transcription in the cell nucleus is a complex and highly regulated process. Transcription in eukaryotes requires three distinct RNA polymerases, each of which employs its own mechanisms for initiation, elongation, and termination. Termination mechanisms vary considerably, ranging from relatively simple to exceptionally complex. In this review, we describe the present state of knowledge on how each of the three RNA polymerases terminates and how mechanisms are conserved, or vary, from yeast to human. PMID:19487567

  6. 7 CFR 1216.29 - Terminate.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE PEANUT PROMOTION, RESEARCH, AND INFORMATION ORDER Peanut Promotion, Research, and Information Order Definitions § 1216.29 Terminate....

  7. 7 CFR 1216.29 - Terminate.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE PEANUT PROMOTION, RESEARCH, AND INFORMATION ORDER Peanut Promotion, Research, and Information Order Definitions § 1216.29 Terminate....

  8. 7 CFR 1216.29 - Terminate.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE PEANUT PROMOTION, RESEARCH, AND INFORMATION ORDER Peanut Promotion, Research, and Information Order Definitions § 1216.29 Terminate....

  9. 7 CFR 1216.29 - Terminate.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE PEANUT PROMOTION, RESEARCH, AND INFORMATION ORDER Peanut Promotion, Research, and Information Order Definitions § 1216.29 Terminate....

  10. 7 CFR 1216.29 - Terminate.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE PEANUT PROMOTION, RESEARCH, AND INFORMATION ORDER Peanut Promotion, Research, and Information Order Definitions § 1216.29 Terminate....

  11. 7 CFR 1280.125 - Terminate.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE LAMB PROMOTION, RESEARCH, AND INFORMATION ORDER Lamb Promotion, Research, and Information Order Definitions § 1280.125 Terminate....

  12. St. James marine terminal facility description

    SciTech Connect

    Not Available

    1993-10-01

    The US Department of Energy (DOE) currently owns and operates a marine terminal on the west bank of the Mississippi River at St. James, Louisiana. The St. James facility was constructed by the Department to provide marine services associated with the fill and drawdown of the Strategic Petroleum Reserve (SPR) crude oil storage facilities located at Bayou Choctaw and Weeks Island, Louisiana. Although strategic to the mission of the SPR in the event of a national emergency, the St. James terminal is situated such that it has a high potential to also serve the commercial industry`s needs for crude oil terminalling and storage. The St. James terminal is located approximately 45 miles west of New Orleans and 30 miles southeast of Baton Rouge, and approximately 160 miles upstream from the mouth of the Mississippi River. Construction of the St. James terminal was initiated in 1978 and was completed in 1980. Since then, the terminal has received and transferred over 125 million barrels of crude oil to the SPR sites for storage. For crude oil distribution, the St. James terminal was connected to the neighboring LOCAP terminal by a 0.1 mile 36-inch pipeline in 1981 and to the Capline terminal by a 0.5 mile 30-inch pipeline in 1988. The terminal also has a 30-inch pipeline connection to the Koch oil terminal which was used for initial fill purposes; however, this pipeline has been disconnected and is currently inactive. A complete description of the St. James terminal facilities, operational capabilities, operational certifications, and future Government requirements are presented in Sections 2, 3, 4, and 5 respectively.

  13. Differential isotope dansylation labeling combined with liquid chromatography mass spectrometry for quantification of intact and N-terminal truncated proteins.

    PubMed

    Tang, Yanan; Li, Liang

    2013-08-20

    The N-terminal amino acids of proteins are important structure units for maintaining the biological function, localization, and interaction networks of proteins. Under different biological conditions, one or several N-terminal amino acids could be cleaved from an intact protein due to processes, such as proteolysis, resulting in the change of protein properties. Thus, the ability to quantify the N-terminal truncated forms of proteins is of great importance, particularly in the area of development and production of protein-based drugs where the relative quantity of the intact protein and its truncated form needs to be monitored. In this work, we describe a rapid method for absolute quantification of protein mixtures containing intact and N-terminal truncated proteins. This method is based on dansylation labeling of the N-terminal amino acids of proteins, followed by microwave-assisted acid hydrolysis of the proteins into amino acids. It is shown that dansyl labeled amino acids are stable in acidic conditions and can be quantified by liquid chromatography mass spectrometry (LC-MS) with the use of isotope analog standards.

  14. Reactions to Termination of Individual Treatment.

    ERIC Educational Resources Information Center

    Fortune, Anne E.; And Others

    1992-01-01

    Queried 69 social workers about termination reactions in most recently terminated individual cases. Clients' strongest reactions were positive affect, evaluation of success, evaluation of therapeutic experience, and positive flight. Least strong client reactions were nihilistic flight, regression, denial, recapitulation, and expression of need for…

  15. The OCLC Terminal: An Instruction Manual.

    ERIC Educational Resources Information Center

    Arnold, Jane; And Others

    Prepared for users of OCLC terminals at the Michigan State University library, this manual provides a brief description of the contents of the OCLC database, instructions for constructing search requests in OCLC, guidelines for interpreting OCLC search results, a key to "reading" the OCLC screen, an overview of typical terminal responses…

  16. 42 CFR 2a.8 - Termination.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Termination. 2a.8 Section 2a.8 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL PROVISIONS PROTECTION OF IDENTITY-RESEARCH SUBJECTS § 2a.8 Termination. (a) A Confidentiality Certificate is in effect from the date of...

  17. 42 CFR 2a.8 - Termination.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Termination. 2a.8 Section 2a.8 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL PROVISIONS PROTECTION OF IDENTITY-RESEARCH SUBJECTS § 2a.8 Termination. (a) A Confidentiality Certificate is in effect from the date of...

  18. 42 CFR 2a.8 - Termination.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Termination. 2a.8 Section 2a.8 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL PROVISIONS PROTECTION OF IDENTITY-RESEARCH SUBJECTS § 2a.8 Termination. (a) A Confidentiality Certificate is in effect from the date of...

  19. 42 CFR 2a.8 - Termination.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Termination. 2a.8 Section 2a.8 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL PROVISIONS PROTECTION OF IDENTITY-RESEARCH SUBJECTS § 2a.8 Termination. (a) A Confidentiality Certificate is in effect from the date of...

  20. 42 CFR 2a.8 - Termination.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Termination. 2a.8 Section 2a.8 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL PROVISIONS PROTECTION OF IDENTITY-RESEARCH SUBJECTS § 2a.8 Termination. (a) A Confidentiality Certificate is in effect from the date of...

  1. 34 CFR 74.61 - Termination.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 34 Education 1 2012-07-01 2012-07-01 false Termination. 74.61 Section 74.61 Education Office of the Secretary, Department of Education ADMINISTRATION OF GRANTS AND AGREEMENTS WITH INSTITUTIONS OF HIGHER EDUCATION, HOSPITALS, AND OTHER NON-PROFIT ORGANIZATIONS Post-Award Requirements Termination...

  2. 21 CFR 312.44 - Termination.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Termination. 312.44 Section 312.44 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS FOR HUMAN USE INVESTIGATIONAL NEW DRUG APPLICATION Administrative Actions § 312.44 Termination. (a) General. This...

  3. 10 CFR 436.38 - Terminating contracts.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Terminating contracts. 436.38 Section 436.38 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION FEDERAL ENERGY MANAGEMENT AND PLANNING PROGRAMS Methods and Procedures for Energy Savings Performance Contracting § 436.38 Terminating contracts. (a) Except as...

  4. Optoelectronic Terminal-Attractor-Based Associative Memory

    NASA Technical Reports Server (NTRS)

    Liu, Hua-Kuang; Barhen, Jacob; Farhat, Nabil H.

    1994-01-01

    Report presents theoretical and experimental study of optically and electronically addressable optical implementation of artificial neural network that performs associative recall. Shows by computer simulation that terminal-attractor-based associative memory can have perfect convergence in associative retrieval and increased storage capacity. Spurious states reduced by exploiting terminal attractors.

  5. Device for reflowing electrodeposited solder on terminals

    NASA Technical Reports Server (NTRS)

    Johnson, W. C.

    1969-01-01

    Terminals are reflowed in a hot strata and solidified in a cooler strata, without physical contact with each other, any fixturing, or the container. Terminals are passed through the upper portion of a reflow flask containing hot peanut oil, and then through the lower portion containing oil at ambient temperatures.

  6. 22 CFR 145.61 - Termination.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... conditions of an award. (2) By the Department, with the consent of the recipient, in which case the two parties shall agree upon the termination conditions, including the effective date and, in the case of... written notification setting forth the reasons for such termination, the effective date, and, in the...

  7. Personal-Computer Video-Terminal Emulator

    NASA Technical Reports Server (NTRS)

    Buckley, R. H.; Koromilas, A.; Smith, R. M.; Lee, G. E.; Giering, E. W.

    1985-01-01

    OWL-1200 video terminal emulator has been written for IBM Personal Computer. The OWL-1200 is a simple user terminal with some intelligent capabilities. These capabilities include screen formatting and block transmission of data. Emulator is written in PASCAL and Assembler for the IBM Personal Computer operating under DOS 1.1.

  8. 25 CFR 11.1114 - Termination.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... functions; (iii) The parent(s) has subjected the minor to willful and repeated acts of sexual abuse; (iv... Minor-in-Need-of-Care Procedure § 11.1114 Termination. (a) Parental rights to a child may be terminated by the children's court according to the procedures in this section. (b) Proceedings to...

  9. 25 CFR 11.1114 - Termination.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... functions; (iii) The parent(s) has subjected the minor to willful and repeated acts of sexual abuse; (iv... Minor-in-Need-of-Care Procedure § 11.1114 Termination. (a) Parental rights to a child may be terminated by the children's court according to the procedures in this section. (b) Proceedings to...

  10. 25 CFR 11.1114 - Termination.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... functions; (iii) The parent(s) has subjected the minor to willful and repeated acts of sexual abuse; (iv... Minor-in-Need-of-Care Procedure § 11.1114 Termination. (a) Parental rights to a child may be terminated by the children's court according to the procedures in this section. (b) Proceedings to...

  11. 25 CFR 11.1114 - Termination.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... functions; (iii) The parent(s) has subjected the minor to willful and repeated acts of sexual abuse; (iv... Minor-in-Need-of-Care Procedure § 11.1114 Termination. (a) Parental rights to a child may be terminated by the children's court according to the procedures in this section. (b) Proceedings to...

  12. 25 CFR 11.1114 - Termination.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... functions; (iii) The parent(s) has subjected the minor to willful and repeated acts of sexual abuse; (iv... Minor-in-Need-of-Care Procedure § 11.1114 Termination. (a) Parental rights to a child may be terminated by the children's court according to the procedures in this section. (b) Proceedings to...

  13. 75 FR 49510 - Credit Watch Termination Initiative

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-13

    ... Housing--Federal Housing Commissioner, HUD. ACTION: Notice. SUMMARY: This notice advises of the cause and effect of termination of Origination Approval Agreements taken by HUD's Federal Housing Administration... Board under HUD's regulations at 24 CFR part 25. Cause: HUD's regulations permit HUD to terminate...

  14. 75 FR 17944 - Credit Watch Termination Initiative

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-08

    ... Housing--Federal Housing Commissioner, HUD. ACTION: Notice. SUMMARY: This notice advises of the cause and effect of termination of Origination Approval Agreements taken by HUD's Federal Housing Administration... ] Board under HUD's regulations at 24 CFR part 25. Cause: HUD's regulations permit HUD to terminate...

  15. 10 CFR 436.38 - Terminating contracts.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 3 2011-01-01 2011-01-01 false Terminating contracts. 436.38 Section 436.38 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION FEDERAL ENERGY MANAGEMENT AND PLANNING PROGRAMS Methods and... termination procedures of the Federal Acquisition Regulation in 48 CFR part 49. (b) In the event an...

  16. Terminals in Libraries: Help or Hazard?

    ERIC Educational Resources Information Center

    Byerly, Greg; Lindell, Signe

    1982-01-01

    This essay and 48-item annotated bibliography provide information on potential problems of computer terminal use--cathode ray tube, video display unit, video display terminal--in libraries. Information on ergonomics (matching people to machines in humane way), eyes and vision, and radiation is included. (EJS)

  17. 76 FR 32316 - Gap in Termination Provisions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-06

    ... Copyright Office 37 CFR Part 201 Gap in Termination Provisions AGENCY: Copyright Office, Library of Congress... termination provisions apply in circumstances where an author agreed to make a grant prior to January 1, 1978... provisions. It also considered transfer of copyrights and renewal rights under common law, prior to...

  18. 75 FR 72771 - Gap in Termination Provisions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-26

    ... Copyright Office 37 CFR Part 201 Gap in Termination Provisions AGENCY: Copyright Office, Library of Congress... after January 1, 1978 (the effective date of the 1976 Copyright Act). However, the provisions do not...), the Office sought comments as to whether or how the termination provisions apply in...

  19. 50 CFR 14.110 - Terminal facilities.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Wild Mammals and Birds to the United States § 14.110 Terminal facilities. (a) Any terminal facility used for wild mammal or bird transport in the country of export, stopover countries, or the United States shall contain an animal holding area or areas. No carrier or shipper shall co-mingle live...

  20. 50 CFR 14.110 - Terminal facilities.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Wild Mammals and Birds to the United States § 14.110 Terminal facilities. (a) Any terminal facility used for wild mammal or bird transport in the country of export, stopover countries, or the United States shall contain an animal holding area or areas. No carrier or shipper shall co-mingle live...

  1. 50 CFR 14.110 - Terminal facilities.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Wild Mammals and Birds to the United States § 14.110 Terminal facilities. (a) Any terminal facility used for wild mammal or bird transport in the country of export, stopover countries, or the United States shall contain an animal holding area or areas. No carrier or shipper shall co-mingle live...

  2. 10 CFR 10.36 - Terminations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Terminations. 10.36 Section 10.36 Energy NUCLEAR REGULATORY COMMISSION CRITERIA AND PROCEDURES FOR DETERMINING ELIGIBILITY FOR ACCESS TO RESTRICTED DATA OR NATIONAL SECURITY INFORMATION OR AN EMPLOYMENT CLEARANCE Miscellaneous § 10.36 Terminations. In the...

  3. 10 CFR 10.36 - Terminations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Terminations. 10.36 Section 10.36 Energy NUCLEAR REGULATORY COMMISSION CRITERIA AND PROCEDURES FOR DETERMINING ELIGIBILITY FOR ACCESS TO RESTRICTED DATA OR NATIONAL SECURITY INFORMATION OR AN EMPLOYMENT CLEARANCE Miscellaneous § 10.36 Terminations. In the...

  4. 10 CFR 10.36 - Terminations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Terminations. 10.36 Section 10.36 Energy NUCLEAR REGULATORY COMMISSION CRITERIA AND PROCEDURES FOR DETERMINING ELIGIBILITY FOR ACCESS TO RESTRICTED DATA OR NATIONAL SECURITY INFORMATION OR AN EMPLOYMENT CLEARANCE Miscellaneous § 10.36 Terminations. In the...

  5. 10 CFR 10.36 - Terminations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Terminations. 10.36 Section 10.36 Energy NUCLEAR REGULATORY COMMISSION CRITERIA AND PROCEDURES FOR DETERMINING ELIGIBILITY FOR ACCESS TO RESTRICTED DATA OR NATIONAL SECURITY INFORMATION OR AN EMPLOYMENT CLEARANCE Miscellaneous § 10.36 Terminations. In the...

  6. 10 CFR 10.36 - Terminations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Terminations. 10.36 Section 10.36 Energy NUCLEAR REGULATORY COMMISSION CRITERIA AND PROCEDURES FOR DETERMINING ELIGIBILITY FOR ACCESS TO RESTRICTED DATA OR NATIONAL SECURITY INFORMATION OR AN EMPLOYMENT CLEARANCE Miscellaneous § 10.36 Terminations. In the...

  7. 22 CFR 62.78 - Termination.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Termination. 62.78 Section 62.78 Foreign Relations DEPARTMENT OF STATE PUBLIC DIPLOMACY AND EXCHANGES EXCHANGE VISITOR PROGRAM Student and Exchange Visitor Information System (SEVIS) § 62.78 Termination. An exchange visitor who willfully or...

  8. 22 CFR 62.78 - Termination.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 22 Foreign Relations 1 2014-04-01 2014-04-01 false Termination. 62.78 Section 62.78 Foreign Relations DEPARTMENT OF STATE PUBLIC DIPLOMACY AND EXCHANGES EXCHANGE VISITOR PROGRAM Student and Exchange Visitor Information System (SEVIS) § 62.78 Termination. An exchange visitor who willfully or...

  9. 22 CFR 62.78 - Termination.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Termination. 62.78 Section 62.78 Foreign Relations DEPARTMENT OF STATE PUBLIC DIPLOMACY AND EXCHANGES EXCHANGE VISITOR PROGRAM Student and Exchange Visitor Information System (SEVIS) § 62.78 Termination. An exchange visitor who willfully or...

  10. 22 CFR 62.78 - Termination.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 22 Foreign Relations 1 2012-04-01 2012-04-01 false Termination. 62.78 Section 62.78 Foreign Relations DEPARTMENT OF STATE PUBLIC DIPLOMACY AND EXCHANGES EXCHANGE VISITOR PROGRAM Student and Exchange Visitor Information System (SEVIS) § 62.78 Termination. An exchange visitor who willfully or...

  11. 22 CFR 62.78 - Termination.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 22 Foreign Relations 1 2013-04-01 2013-04-01 false Termination. 62.78 Section 62.78 Foreign Relations DEPARTMENT OF STATE PUBLIC DIPLOMACY AND EXCHANGES EXCHANGE VISITOR PROGRAM Student and Exchange Visitor Information System (SEVIS) § 62.78 Termination. An exchange visitor who willfully or...

  12. 9 CFR 3.40 - Terminal facilities.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Pigs and Hamsters Transportation Standards § 3.40 Terminal facilities. No person subject to the Animal Welfare regulations shall commingle shipments of live guinea pigs or hamsters with inanimate cargo. All animal holding areas of a terminal facility where shipments of live guinea pigs or hamsters...

  13. 9 CFR 3.117 - Terminal facilities.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Marine Mammals Transportation Standards § 3.117 Terminal facilities. Carriers and intermediate handlers must not commingle marine mammal shipments with inanimate cargo. All animal holding areas of a terminal facility of any carrier or intermediate handler where marine mammal shipments are maintained must...

  14. Terminal operators blending efficiency with tight regulations

    SciTech Connect

    Gonzalez, R.G.

    1997-06-01

    The cost of terminal operations can be a manageable industry issue with the changeover from the EPA Simple Model to the Complex Model Phase II. In 1992 refiners and terminal operators were concerned that keeping conventional gasoline separate from RFG would be a daunting task, and the term {open_quotes}commingling{close_quotes} became part of the industry lingo, as conventional fuels can be commingled in the pipeline while batches of RFG must be kept separate from conventional and other reformulated fuels. In 1995 the concern focused on keeping RFG batches separate, produced from each individual refinery, because each refinery had its own unique baseline. From a business perspective, terminal facilities are too expensive to be a core segment of an oil company`s assets. Terminal facilities also pose a great liability. Vertically integrated oil companies may do better by outsourcing terminal facility operations. It also could be a win-win situation when refiners consolidate terminal facilities. The added EPA driven regulatory cost layers concentrated within the terminal facility make it difficult to achieve a positive return on investment from the terminal.

  15. 24 CFR 203.295 - Voluntary termination.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... insurance contract on any mortgage under this part covering a 1-to-4 family residence. The mortgagee shall... the Commissioner on or after May 1, 1972. Termination of Insurance Contract ... SINGLE FAMILY MORTGAGE INSURANCE Contract Rights and Obligations Voluntary Termination §...

  16. 7 CFR 906.55 - Termination.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Termination. 906.55 Section 906.55 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... of this subpart shall, in any event, terminate whenever the provisions of the act authorizing...

  17. 32 CFR 241.7 - Termination.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 2 2014-07-01 2014-07-01 false Termination. 241.7 Section 241.7 National Defense Department of Defense (Continued) OFFICE OF THE SECRETARY OF DEFENSE (CONTINUED) MISCELLANEOUS PILOT PROGRAM FOR TEMPORARY EXCHANGE OF INFORMATION TECHNOLOGY PERSONNEL § 241.7 Termination....

  18. Photovoltaic module electrical termination design requirement study

    NASA Technical Reports Server (NTRS)

    Mosna, F. J., Jr.; Donlinger, J.

    1980-01-01

    Pertinent electrical termination attributes were identified and used in the development of selection criteria which included function, environmental durability, utility, manufacturing, code, and cost. Significant aspects of each criteria are discussed, and eight different types of terminations are ranked according to their performance in remote, residential, intermediate, and industrial applications.

  19. 78 FR 5717 - Safety Zone; Military Ocean Terminal Concord Safety Zone, Suisun Bay, Military Ocean Terminal...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-28

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Military Ocean Terminal Concord Safety Zone, Suisun Bay, Military Ocean Terminal Concord, CA AGENCY: Coast Guard, DHS. ACTION: Interim rule and... Suisun Bay near Military Ocean Terminal Concord, CA in support of military onload and offload...

  20. 76 FR 4364 - Credit Watch Termination Initiative; Termination of Direct Endorsement (DE) Approval

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-25

    .... SUMMARY: This notice advises of the cause and effect of termination of Direct Endorsement (DE) Approval... Board under HUD's regulations at 24 CFR part 25. Cause: HUD's regulations permit HUD to terminate the DE... exceeds both the national rate and 250 percent of the field office rate. Effect: Termination of the...

  1. 76 FR 53148 - Credit Watch Termination Initiative; Termination of Direct Endorsement (DE) Approval

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-25

    .... SUMMARY: This notice advises of the cause and effect of termination of Direct Endorsement (DE) Approval... Board under HUD's regulations at 24 CFR part 25. Cause: HUD's regulations permit HUD to terminate the DE... exceeds both the national rate and 200 percent of the field office rate. Effect: Termination of the...

  2. 77 FR 38817 - Credit Watch Termination Initiative; Termination of Direct Endorsement (DE) Approval

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-29

    .... SUMMARY: This notice advises of the cause and effect of termination of Direct Endorsement (DE) Approval... Board under HUD's regulations at 24 CFR part 25. ] Cause: HUD's regulations permit HUD to terminate the... rate exceeds both the national rate and 200 percent of the field office rate. Effect: Termination...

  3. 76 FR 22120 - Credit Watch Termination Initiative; Termination of Origination Approval Agreements

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-20

    .... SUMMARY: This notice advises of the cause and effect of termination of Origination Approval Agreements.... Cause: HUD's regulations permit HUD to terminate the Agreement with any mortgagee having a default and... field office rate. Effect: Termination of the Agreement precludes branch(es) of the mortgagee...

  4. 75 FR 67388 - Credit Watch Termination Initiative; Termination of Direct Endorsement (DE) Approval

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-02

    .... SUMMARY: This notice advises of the cause and effect of termination of Direct Endorsement (DE) Approval... Board under HUD's regulations at 24 CFR part 25. Cause: HUD's regulations permit HUD to terminate the DE... both the national rate and 300 percent of the field office rate. Effect: Termination of the DE...

  5. 75 FR 61165 - Credit Watch Termination Initiative Termination of Direct Endorsement (DE) Approval

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-04

    .... SUMMARY: This notice advises of the cause and effect of termination of Direct Endorsement (DE) Approval... Board under HUD's regulations at 24 CFR part 25. Cause: HUD's regulations permit HUD to terminate the DE... both the national rate and 300 percent of the field office rate. Effect: Termination of the DE...

  6. 76 FR 38406 - Credit Watch Termination Initiative; Termination of Origination Approval Agreements

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-30

    .... SUMMARY: This notice advises of the cause and effect of termination of Origination Approval Agreements.... Cause: HUD's regulations permit HUD to terminate the Agreement with any mortgagee having a default and... field office rate. Effect: Termination of the Agreement precludes branch(es) of the mortgagee...

  7. Leptospira Immunoglobulin-Like Protein B (LigB) Binds to Both the C-Terminal 23 Amino Acids of Fibrinogen αC Domain and Factor XIII: Insight into the Mechanism of LigB-Mediated Blockage of Fibrinogen α Chain Cross-Linking

    PubMed Central

    Hsieh, Ching-Lin; Chang, Eric; Tseng, Andrew; Ptak, Christopher; Wu, Li-Chen; Su, Chun-Li; McDonough, Sean P.; Lin, Yi-Pin; Chang, Yung-Fu

    2016-01-01

    The coagulation system provides a primitive but effective defense against hemorrhage. Soluble fibrinogen (Fg) monomers, composed of α, β and γ chains, are recruited to provide structural support for the formation of a hemostatic plug. Fg binds to platelets and is processed into a cross-linked fibrin polymer by the enzymatic clotting factors, thrombin and Factor XIII (FXIII). The newly formed fibrin-platelet clot can act as barrier to protect against pathogens from entering the bloodstream. Further, injuries caused by bacterial infections can be confined to the initial wound site. Many pathogenic bacteria have Fg-binding adhesins that can circumvent the coagulation pathway and allow the bacteria to sidestep containment. Fg expression is upregulated during lung infection providing an attachment surface for bacteria with the ability to produce Fg-binding adhesins. Fg binding by leptospira might play a crucial factor in Leptospira-associated pulmonary hemorrhage, the main factor contributing to lethality in severe cases of leptospirosis. The 12th domain of Leptospira immunoglobulin-like protein B (LigB12), a leptospiral adhesin, interacts with the C-terminus of FgαC (FgαCC). In this study, the binding site for LigB12 was mapped to the final 23 amino acids at the C-terminal end of FgαCC (FgαCC8). The association of FgαCC8 with LigB12 (ELISA, KD = 0.76 μM; SPR, KD = 0.96 μM) was reduced by mutations of both charged residues (R608, R611 and H614 from FgαCC8; D1061 from LigB12) and hydrophobic residues (I613 from FgαCC8; F1054 and A1065 from LigB12). Additionally, LigB12 bound strongly to FXIII and also inhibited fibrin formation, suggesting that LigB can disrupt coagulation by suppressing FXIII activity. Here, the detailed binding mechanism of a leptospiral adhesin to a host hemostatic factor is characterized for the first time and should provide better insight into the pathogenesis of leptospirosis. PMID:27622634

  8. Multiple roles of genome-attached bacteriophage terminal proteins

    SciTech Connect

    Redrejo-Rodríguez, Modesto; Salas, Margarita

    2014-11-15

    Protein-primed replication constitutes a generalized mechanism to initiate DNA or RNA synthesis in linear genomes, including viruses, gram-positive bacteria, linear plasmids and mobile elements. By this mechanism a specific amino acid primes replication and becomes covalently linked to the genome ends. Despite the fact that TPs lack sequence homology, they share a similar structural arrangement, with the priming residue in the C-terminal half of the protein and an accumulation of positively charged residues at the N-terminal end. In addition, various bacteriophage TPs have been shown to have DNA-binding capacity that targets TPs and their attached genomes to the host nucleoid. Furthermore, a number of bacteriophage TPs from different viral families and with diverse hosts also contain putative nuclear localization signals and localize in the eukaryotic nucleus, which could lead to the transport of the attached DNA. This suggests a possible role of bacteriophage TPs in prokaryote-to-eukaryote horizontal gene transfer. - Highlights: • Protein-primed genome replication constitutes a strategy to initiate DNA or RNA synthesis in linear genomes. • Bacteriophage terminal proteins (TPs) are covalently attached to viral genomes by their primary function priming DNA replication. • TPs are also DNA-binding proteins and target phage genomes to the host nucleoid. • TPs can also localize in the eukaryotic nucleus and may have a role in phage-mediated interkingdom gene transfer.

  9. High Temperature VARTM of Phenylethynyl Terminated Imides

    NASA Technical Reports Server (NTRS)

    Cano, Roberto J.; Britton, Sean M.; Jensen, Brian J.; Connell, John W.; Herring, Helen M.; Linberry, Quentin J.; Ghose, Sayata; Watson, Kent A.

    2009-01-01

    Fabrication of composite structures using vacuum assisted resin transfer molding (VARTM) is generally more affordable than conventional autoclave techniques. Recent efforts have focused on adapting VARTM for the fabrication of high temperature composites. Due to their low melt viscosity and long melt stability, certain phenylethynyl terminated imides (PETI) can be processed into composites using high temperature VARTM (HT-VARTM). However, one of the disadvantages of the current HT-VARTM resin systems has been the high porosity of the resultant composites. For aerospace applications, the desired void fraction of less than 2% has not yet been achieved. In the current study, two PETI resins, LaRC PETI-330 and LaRC PETI-8 have been used to make test specimens using HT-VARTM. The resins were infused into ten layers of IM7-6K carbon fiber 5-harness satin fabric at 260 C or 280 C and cured at 371 C. Initial runs yielded composites with high void content, typically greater than 7% by weight. A thermogravimetric-mass spectroscopic study was conducted to determine the source of volatiles leading to high porosity. It was determined that under the thermal cycle used for laminate fabrication, the phenylethynyl endcap was undergoing degradation leading to volatile evolution. By modifying the thermal cycle used in laminate fabrication, the void content was reduced significantly (typically approximately 3%). Densities of the composites were determined using a density gradient column and the glass transition temperatures of the cured composites were measured by dynamic mechanical analysis. Photomicrographs of the panels were taken and void contents were determined by acid digestion. The results of this work are presented herein.

  10. Substrate specificity of mammalian N-terminal α-amino methyltransferase

    PubMed Central

    Petkowski, Janusz J.; Schaner Tooley, Christine E.; Anderson, Lissa C.; Shumilin, Igor A.; Balsbaugh, Jeremy L.; Shabanowitz, Jeffrey; Hunt, Donald F.; Minor, Wladek; Macara, Ian G.

    2012-01-01

    N-terminal methylation of free α-amino-groups is a post-translational modification of proteins that has been known for 30 years but has been very little studied. In this modification, the initiating M residue is cleaved and the exposed α-amino group is mono- di- or trimethylated by NRMT, a recently identified N-terminal methyltransferase. Currently, all known eukaryotic α-aminomethylated proteins have a unique N-terminal motif, M-X-P-K, where X is A, P, or S. NRMT can also methylate artificial substrates in vitro in which X is G, F, Y, C, M, K, R, N, Q or H. Methylation efficiencies of N-terminal amino acids are variable with respect to the identity of X. Here we use in vitro peptide methylation assays and substrate immunoprecipitations to show that the canonical M-X-P-K methylation motif is not the only one recognized by NRMT. We predict that N-terminal methylation is a widespread post-translational modification, and that there is interplay between N-terminal acetylation and N-terminal methylation. We also use isothermal calorimetry experiments to demonstrate that NRMT can efficiently recognize and bind to its fully methylated products. PMID:22769851

  11. Fault terminations, Seminoe Mountains, Wyoming

    SciTech Connect

    Dominic, J.B.; McConnell, D.A. . Dept. of Geology)

    1992-01-01

    Two basement-involved faults terminate in folds in the Seminoe Mountains. Mesoscopic and macroscopic structures in sedimentary rocks provide clues to the interrelationship of faults and folds in this region, and on the linkage between faulting and folding in general. The Hurt Creek fault trends 320[degree] and has maximum separation of 1.5 km measured at the basement/cover contact. Separation on the fault decreases upsection to zero within the Jurassic Sundance Formation. Unfaulted rock units form an anticline around the fault tip. The complementary syncline is angular with planar limbs and a narrow hinge zone. The syncline axial trace intersects the fault in the footwall at the basement/cover cut-off. Map patterns are interpreted to show thickening of Mesozoic units adjacent to the syncline hinge. In contrast, extensional structures are common in the faulted anticline within the Permian Goose Egg and Triassic Chugwater Formations. A hanging wall splay fault loses separation into the Goose Egg formation which is thinned by 50% at the fault tip. Mesoscopic normal faults are oriented 320--340[degree] and have an average inclination of 75[degree] SW. Megaboudins of Chugwater are present in the footwall of the Hurt Creek fault, immediately adjacent to the fault trace. The Black Canyon fault transported Precambrian-Pennsylvanian rocks over Pennsylvanian Tensleep sandstone. This fault is layer-parallel at the top of the Tensleep and loses separation along strike into an unfaulted syncline in the Goose Egg Formation. Shortening in the pre-Permian units is accommodated by slip on the basement-involved Black Canyon fault. Equivalent shortening in Permian-Cretaceous units occurs on a system of thin-skinned'' thrust faults.

  12. The Sm-like RNA chaperone Hfq mediates transcription antitermination at Rho-dependent terminators

    PubMed Central

    Rabhi, Makhlouf; Espéli, Olivier; Schwartz, Annie; Cayrol, Bastien; Rahmouni, A Rachid; Arluison, Véronique; Boudvillain, Marc

    2011-01-01

    In Escherichia coli, the essential motor protein Rho promotes transcription termination in a tightly controlled manner that is not fully understood. Here, we show that the general post-transcriptional regulatory protein Hfq associates with Rho to regulate Rho function. The Hfq:Rho complex can be further stabilized by RNA bridging both factors in a configuration that inhibits the ATP hydrolysis and duplex unwinding activities of Rho and that mediates transcription antitermination at Rho-dependent terminators in vitro and in vivo. Antitermination at a prototypical terminator (λtR1) requires Hfq binding to an A/U-rich transcript region directly upstream from the terminator. Antitermination is modulated by trans-acting factors (NusG or nucleic acid competitors) that affect Hfq association with Rho or RNA. These data unveil a new Hfq function and a novel transcription regulatory mechanism with potentially important implications for bacterial RNA metabolism, gene silencing, and pathogenicity. PMID:21673658

  13. NMR assignments of the N-terminal domain of Nephila clavipes spidroin 1.

    PubMed

    Parnham, Stuart; Gaines, William A; Duggan, Brendan M; Marcotte, William R; Hennig, Mirko

    2011-10-01

    The building blocks of spider dragline silk are two fibrous proteins secreted from the major ampullate gland named spidroins 1 and 2 (MaSp1, MaSp2). These proteins consist of a large central domain composed of approximately 100 tandem copies of a 35-40 amino acid repeat sequence. Non-repetitive N and C-terminal domains, of which the C-terminal domain has been implicated to transition from soluble and insoluble states during spinning, flank the repetitive core. The N-terminal domain until recently has been largely unknown due to difficulties in cloning and expression. Here, we report nearly complete assignment for all (1)H, (13)C, and (15)N resonances in the 14 kDa N-terminal domain of major ampullate spidroin 1 (MaSp1-N) of the golden orb-web spider Nephila clavipes.

  14. Stability of the heme Fe-N-terminal amino group coordination bond in denatured cytochrome c.

    PubMed

    Tai, Hulin; Munegumi, Toratane; Yamamoto, Yasuhiko

    2009-01-05

    In the denatured states of Hydrogenobacter thermophilus cytochrome c(552) (HT) and Pseudomonas aeruginosa cytochrome c(551) (PA), and their mutants, the N-terminal amino group of the polypeptide chain is coordinated to heme Fe in place of the axial Met, the His-N(term) form being formed. The coordination of the N-terminal amino group to heme Fe leads to loop formation by the N-terminal stretch preceding the first Cys residue bound to the heme, and the N-terminal stretches of HT and PA are different from each other in terms of both the sequence and the number of constituent amino acid residues. The His-N(term) form was shown to be rather stable, and hence it can influence the stability of the denatured state. We have investigated the heme Fe coordination structures and stabilities of the His-N(term) forms emerging upon guanidine hydrochloric acid-induced unfolding of the oxidized forms of the proteins. The Fe-N(term) coordination bond in the His-N(term) form with a 9-residue N-terminal stretch of HT proteins was found to be tilted to some extent away from the heme normal, as reflected by the great heme methyl proton shift spread. On the other hand, the small heme methyl proton shift spread of the His-N(term) form with an 11-residue stretch of PA proteins indicated that its Fe-N(term) bond is nearly parallel with the heme normal. The stability of the His-N(term) form was found to be affected by the structural properties of the N-terminal stretch, such as its length and the N-terminal residue. With a given N-terminal residue, the stability of the His-N(term) form is higher for a 9-residue N-terminal stretch than an 11-residue one. In addition, with a given length of the N-terminal stretch, the His-N(term) form with an N-terminal Glu is stabilized by a few kJ mol(-1) relative to that with an N-terminal Asn. These results provide a novel insight into the stabilizing interactions in the denatured cyts c that will facilitate elucidation of the folding/unfolding mechanisms

  15. Silylene Defect at the Dihydrogen Terminated (100) Si Surface

    NASA Astrophysics Data System (ADS)

    Belanzoni, P.; Giorgi, G.; Sgamellotti, A.; Cerofolini, G. F.

    2009-09-01

    Density functional calculations for both periodic slabs and different size cluster models of the hydrogen-terminated (100) surface of silicon are used to study a new configuration, formed by a silylene center interacting with vicinal silicon dihydrides through nonconventional hydrogen bonds. A comparison between slab-model and cluster-model approaches to modeling surface silylene defect formation processes is presented. The cluster models are used to analyze the structure and bonding of the silylene with a Lewis acid and base, showing the Zwitterionic nature of the defect. The silylene is also demonstrated to behave as a strong Brønsted acid. The stabilization of the silylene defect via interaction with species unavoidably present in the HFaq-etching solution is investigated. Finally, the negative chemical shift observed by X-ray photoelectron spectroscopy in the HFaq-etched (100) Si surface is attributed to the occurrence of silylene defect.

  16. The N-terminal half of membrane CD14 is a functional cellular lipopolysaccharide receptor.

    PubMed

    Viriyakosol, S; Kirkland, T N

    1996-02-01

    CD14, a glycosylphosphatidylinositol-anchored protein on the surface of monocytes, macrophages, and polymorphonuclear leukocytes, is a receptor for lipopolysaccharide (LPS). It was recently reported that an N-terminal 152-amino-acid fragment of soluble CD14 was an active soluble lipopolysaccharide receptor (T. S. -C. Juan, M. J. Kelley, D. A. Johnson, L. A. Busse, E. Hailman, S. D. Wright, and H. S. Lichenstein, J. Biol. Chem. 270:1382-1387, 1995). To determine whether the N-terminal half of the membrane CD14 was a functional LPS receptor on the cell membrane, we engineered a chimeric gene coding for amino acids 1 to 151 of CD14 fused to the C-terminal region of decay-accelerating factor and expressed it in Chinese hamster ovary cells and 70Z/3 cells. We found that the chimeric, truncated CD14 is a fully functional LPS receptor in both cell lines.

  17. Imide Oligomers Containing Pendent and Terminal Phenylethynyl Groups-2

    NASA Technical Reports Server (NTRS)

    Connell, J. W.; Smith, J. G., Jr.; Hergenrother, P. M.

    1998-01-01

    As part of a program to develop high-performance/high-temperature structural resins for aeronautical applications, imide oligomers containing pendent and terminal phenylethynyl groups were prepared, characterized and the cured resins evaluated as composite matrices. The oligomers were prepared at a calculated number-average molecular weight of 5000 g/mol and contained 15-20 mol% pendent phenylethynyl groups. In previous work, an oligomer containing pendent and terminal phenylethynyl groups exhibited a high glass transition temperature (approximately 313 C), and laminates therefrom exhibited high compressive properties, but processability, fracture toughness, microcrack resistance and damage tolerance were less than desired. In an attempt to improve these deficiencies, modifications in the oligomeric backbone involving the incorporation of 1,3-bis(3-aminophenoxy)benzene were investigated as a means of improving processability and toughness without detracting from the high glass transition temperature and high compressive properties. The amide acid oligomeric solutions were prepared in N-methyl-2-pyrrolidinone and were subsequently processed into imide powder, thin films, adhesive tape and carbon fiber prepreg. Neat resin plaques were fabricated from imide powder by compression moulding. The maximum processing pressure was 1.4 MPa and the cure temperature ranged from 350 to 371 C for 1 h for the mouldings, adhesives, films and composites. The properties of the 1,3-bis(3-aniinophenoxy)benzene modified cured imide oligomers containing pendent and terminal phenylethynyl groups are compared with those of previously prepared oligomers containing pendent and terminal phenylethynyl groups of similar composition and molecular weight.

  18. Proving Program Termination With Matrix Weighted Digraphs

    NASA Technical Reports Server (NTRS)

    Dutle, Aaron

    2015-01-01

    Program termination analysis is an important task in logic and computer science. While determining if a program terminates is known to be undecidable in general, there has been a significant amount of attention given to finding sufficient and computationally practical conditions to prove termination. One such method takes a program and builds from it a matrix weighted digraph. These are directed graphs whose edges are labeled by square matrices with entries in {-1,0,1}, equipped with a nonstandard matrix multiplication. Certain properties of this digraph are known to imply the termination of the related program. In particular, termination of the program can be determined from the weights of the circuits in the digraph. In this talk, the motivation for addressing termination and how matrix weighted digraphs arise will be briefly discussed. The remainder of the talk will describe an efficient method for bounding the weights of a finite set of the circuits in a matrix weighted digraph, which allows termination of the related program to be deduced.

  19. Compact Termination for Structural Soft-goods

    NASA Technical Reports Server (NTRS)

    Wilkes, Robert, Jr.

    2013-01-01

    Glass fiber is unique in its ability to withstand atomic oxygen and ultraviolet radiation in-space environments. However, glass fiber is also difficult to terminate by traditional methods without decreasing its strength significantly. Glass fiber products are especially sensitive to bend radius, and do not work very well with traditional 'sewn loop on pin' type connections. As with most composites, getting applied loads from a metallic structure into the webbing without stress concentrations is the key to a successful design. A potted end termination has been shown in some preliminary work to out-perform traditional termination methods. It was proposed to conduct a series of tensile tests on structural webbing or cord to determine the optimum potting geometry, and to then be able to estimate a weight and volume savings over traditional sewn-overa- pin connections. During the course of the investigation into potted end terminations for glass fiber webbing, a new and innovative connection was developed that has lower weight, reduced fabrication time, and superior thermal tolerance over the metallic end terminations that were to be optimized in the original proposal. This end termination essentially transitions the flexible glass fiber webbing into a rigid fiberglass termination, which can be bolted/fastened with traditional methods

  20. Osteogenic cell differentiation on H-terminated and O-terminated nanocrystalline diamond films.

    PubMed

    Liskova, Jana; Babchenko, Oleg; Varga, Marian; Kromka, Alexander; Hadraba, Daniel; Svindrych, Zdenek; Burdikova, Zuzana; Bacakova, Lucie

    2015-01-01

    Nanocrystalline diamond (NCD) films are promising materials for bone implant coatings because of their biocompatibility, chemical resistance, and mechanical hardness. Moreover, NCD wettability can be tailored by grafting specific atoms. The NCD films used in this study were grown on silicon substrates by microwave plasma-enhanced chemical vapor deposition and grafted by hydrogen atoms (H-termination) or oxygen atoms (O-termination). Human osteoblast-like Saos-2 cells were used for biological studies on H-terminated and O-terminated NCD films. The adhesion, growth, and subsequent differentiation of the osteoblasts on NCD films were examined, and the extracellular matrix production and composition were quantified. The osteoblasts that had been cultivated on the O-terminated NCD films exhibited a higher growth rate than those grown on the H-terminated NCD films. The mature collagen fibers were detected in Saos-2 cells on both the H-terminated and O-terminated NCD films; however, the quantity of total collagen in the extracellular matrix was higher on the O-terminated NCD films, as were the amounts of calcium deposition and alkaline phosphatase activity. Nevertheless, the expression of genes for osteogenic markers - type I collagen, alkaline phosphatase, and osteocalcin - was either comparable on the H-terminated and O-terminated films or even lower on the O-terminated films. In conclusion, the higher wettability of the O-terminated NCD films is promising for adhesion and growth of osteoblasts. In addition, the O-terminated surface also seems to support the deposition of extracellular matrix proteins and extracellular matrix mineralization, and this is promising for better osteoconductivity of potential bone implant coatings.

  1. Production of high molecular weight polylactic acid

    DOEpatents

    Bonsignore, Patrick V.

    1995-01-01

    A degradable high molecular weight poly(lactic acid). A poly(lactic acid) has a terminal end group of one of carboxyl or hydroxyl groups with low molecular weight poly(lactic acid) units coupled with linking agents of di-isocyanates, bis-epoxides, bis-oxazolines and bis-ortho esters. The resulting high molecular weight poly(lactic acid) can be used for applications taking advantage of the improved physical properties.

  2. Production of high molecular weight polylactic acid

    DOEpatents

    Bonsignore, P.V.

    1995-11-28

    A degradable high molecular weight poly(lactic acid) is described. The poly(lactic acid) has a terminal end group of one of carboxyl or hydroxyl groups with low molecular weight poly(lactic acid) units coupled with linking agents of di-isocyanates, bis-epoxides, bis-oxazolines and bis-ortho esters. The resulting high molecular weight poly(lactic acid) can be used for applications taking advantage of the improved physical properties.

  3. 29 CFR 4041.41 - Requirements for a distress termination.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... continue in business outside the reorganization process and approves the plan termination. (3) Inability to... TERMINATIONS TERMINATION OF SINGLE-EMPLOYER PLANS Distress Termination Process § 4041.41 Requirements for a... plan must initiate the termination process again, starting with the issuance of a new notice of...

  4. 42 CFR 489.53 - Termination by CMS.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 5 2014-10-01 2014-10-01 false Termination by CMS. 489.53 Section 489.53 Public... Reinstatement After Termination § 489.53 Termination by CMS. (a) Basis for termination of agreement with any provider. CMS may terminate the agreement with any provider if CMS finds that any of the following...

  5. 42 CFR 489.53 - Termination by CMS.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 5 2012-10-01 2012-10-01 false Termination by CMS. 489.53 Section 489.53 Public... Reinstatement After Termination § 489.53 Termination by CMS. (a) Basis for termination of agreement with any provider. CMS may terminate the agreement with any provider if CMS finds that any of the following...

  6. 42 CFR 489.53 - Termination by CMS.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 5 2013-10-01 2013-10-01 false Termination by CMS. 489.53 Section 489.53 Public... Reinstatement After Termination § 489.53 Termination by CMS. (a) Basis for termination of agreement with any provider. CMS may terminate the agreement with any provider if CMS finds that any of the following...

  7. 42 CFR 489.53 - Termination by CMS.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 5 2010-10-01 2010-10-01 false Termination by CMS. 489.53 Section 489.53 Public... Reinstatement After Termination § 489.53 Termination by CMS. (a) Basis for termination of agreement with any provider. CMS may terminate the agreement with any provider if CMS finds that any of the following...

  8. 42 CFR 489.53 - Termination by CMS.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 5 2011-10-01 2011-10-01 false Termination by CMS. 489.53 Section 489.53 Public... Reinstatement After Termination § 489.53 Termination by CMS. (a) Basis for termination of agreement with any provider. CMS may terminate the agreement with any provider if CMS finds that any of the following...

  9. Graded junction termination extensions for electronic devices

    NASA Technical Reports Server (NTRS)

    Merrett, J. Neil (Inventor); Isaacs-Smith, Tamara (Inventor); Sheridan, David C. (Inventor); Williams, John R. (Inventor)

    2006-01-01

    A graded junction termination extension in a silicon carbide (SiC) semiconductor device and method of its fabrication using ion implementation techniques is provided for high power devices. The properties of silicon carbide (SiC) make this wide band gap semiconductor a promising material for high power devices. This potential is demonstrated in various devices such as p-n diodes, Schottky diodes, bipolar junction transistors, thyristors, etc. These devices require adequate and affordable termination techniques to reduce leakage current and increase breakdown voltage in order to maximize power handling capabilities. The graded junction termination extension disclosed is effective, self-aligned, and simplifies the implementation process.

  10. Graded junction termination extensions for electronic devices

    NASA Technical Reports Server (NTRS)

    Merrett, J. Neil (Inventor); Isaacs-Smith, Tamara (Inventor); Sheridan, David C. (Inventor); Williams, John R. (Inventor)

    2007-01-01

    A graded junction termination extension in a silicon carbide (SiC) semiconductor device and method of its fabrication using ion implementation techniques is provided for high power devices. The properties of silicon carbide (SiC) make this wide band gap semiconductor a promising material for high power devices. This potential is demonstrated in various devices such as p-n diodes, Schottky diodes, bipolar junction transistors, thyristors, etc. These devices require adequate and affordable termination techniques to reduce leakage current and increase breakdown voltage in order to maximize power handling capabilities. The graded junction termination extension disclosed is effective, self-aligned, and simplifies the implementation process.

  11. Operational benefits from the terminal configured vehicle

    NASA Technical Reports Server (NTRS)

    Reeder, J. P.; Schmitz, R. A.; Clark, L. V.

    1979-01-01

    The NASA Terminal Configured Vehicle is a flying laboratory used to conduct research and development on improved airborne systems (including avionics) and operational flight procedures, with particular emphasis on utilization in the terminal area environment. The objectives of this technology development activity, focused on conventional transport aircraft, are to develop and demonstrate improvements which can lead to increased airport and runway capacity, increased air traffic controller productivity, energy efficient terminal area operations, reduced weather minima with safety, and reduced community noise by use of appropriate procedures. This paper discusses some early results of this activity in addition to defining present efforts and future research plans.

  12. Engineered recombinant enteropeptidase catalytic subunit: effect of N-terminal modification.

    PubMed

    Song, Hye-Won; Choi, Sung-Il; Seong, Baik L

    2002-04-01

    Enteropeptidase (enterokinase) is a serine protease highly specific for recognition and cleavage of the target sequence of Asp-Asp-Asp-Asp-Lys (D4K). The three-dimensional structure of the enteropeptidase shows that the N-terminal amino acid is buried inside the protein providing molecular interactions necessary to maintain the conformation of the active site. To determine the influence of the N-terminal amino acid of enteropeptidase light chain (EK(L)) on the enzymatic activity, we constructed various mutants including 17 different single amino acid substitutions and three different extensions at the N-terminal end. The mutants of recombinant enteropeptidase (rEK(L)) were expressed in Saccharomyces cerevisiae and secreted into culture medium. Among 20 different mutants tested, the only mutant with the Ile --> Val substitution exhibited significant activity. The kinetic properties of the mutant protein were very similar to those of the wild-type rEK(L). Based on the three-dimensional structure where the N-terminal Ile is oriented into hydrophobic pocket, the results suggest that Val could substitute Ile without affecting the active conformation of the enzyme. The results also explain why all trypsin-like serine proteases carry either Ile or Val at the N-termini and none other amino acid residues are found. Moreover, this finding provides a mental framework for expressing the N-terminally engineered enteropeptidase in Escherichia coli, utilizing the known property of the methionine aminopeptidase that exhibits poor activity toward the N-terminal Met-Ile bond, but offers efficient cleavage of the Met-Val bond.

  13. C-terminal functionalization of nylon-3 polymers: effects of C-terminal groups on antibacterial and hemolytic activities.

    PubMed

    Zhang, Jihua; Markiewicz, Matthew J; Mowery, Brendan P; Weisblum, Bernard; Stahl, Shannon S; Gellman, Samuel H

    2012-02-13

    Nylon-3 polymers contain β-amino-acid-derived subunits and can be viewed as higher homologues of poly(α-amino acids). This structural relationship raises the possibility that nylon-3 polymers offer a platform for development of new materials with a variety of biological activities, a prospect that has recently begun to receive experimental support. Nylon-3 homo- and copolymers can be prepared via anionic ring-opening polymerization of β-lactams, and use of an N-acyl-β-lactam as coinitiator in the polymerization reaction allows placement of a specific functional group, borne by the N-acyl-β-lactam, at the N-terminus of each polymer chain. Controlling the unit at the C-termini of nylon-3 polymer chains, however, has been problematic. Here we describe a strategy for specifying C-terminal functionality that is based on the polymerization mechanism. After the anionic ring-opening polymerization is complete, we introduce a new β-lactam, approximately 1 equiv relative to the expected number of polymer chains. Because the polymer chains bear a reactive imide group at their C-termini, this new β-lactam should become attached at this position. If the terminating β-lactam bears a distinctive functional group, that functionality should be affixed to most or all C-termini in the reaction mixture. We use the new technique to compare the impact of N- and C-terminal placement of a critical hydrophobic fragment on the biological activity profile of nylon-3 copolymers. The synthetic advance described here should prove to be generally useful for tailoring the properties of nylon-3 materials.

  14. Terminal Area Conflict Detection and Resolution Tool

    NASA Technical Reports Server (NTRS)

    Verma, Savita Arora

    2011-01-01

    This poster will describe analysis of a conflict detection and resolution tool for the terminal area called T-TSAFE. With altitude clearance information, the tool can reduce false alerts to as low as 2 per hour.

  15. 46 CFR Sec. 3 - Terminal operating contract.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... supervision and direction of all operations at any terminal where the operator may perform services hereunder... indirect compensation and selection for training, except where such provisions are governed by State...

  16. 48 CFR 801.690-7 - Termination.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Responsibilities 801.690-7 Termination. (a) The DSPE (for all warrant levels) or HCA (for Micro-purchase Level and... changes in the status (e.g., departure, name, position, or grade change) of a micro-purchase cardholder...

  17. Near-terminator photography, part R

    NASA Technical Reports Server (NTRS)

    Head, J. W.; Lloyd, D. D.

    1972-01-01

    The advantages resulting from the use of near-terminator photography in lunar surface investigations are discussed. It is pointed out that, under near-terminator conditions, small changes in slope produce greater contrast changes than at high sun elevation angles. This desirable phenomenon is confirmed by an examination of the near-terminator photography taken during the Apollo 15 mission. Many of the photographs obtained show lunar surface areas within a few degrees of the terminator and are therefore of significant geologic interest. In addition, many geologic features stand out in a distinct manner not normal in conventional lunar photography, thus providing additional data on the surface morphology and the configuration of a large number of lunar surface structures.

  18. Oligomers Terminated By Maleimide And Acetylene

    NASA Technical Reports Server (NTRS)

    St. Clair, Terry L.; Pater, Ruth H.; Gerber, Margaret K.

    1994-01-01

    Oligomeric molecules terminated with maleimide and acetylene groups synthesized and thermally treated to form cross-linked polymers exhibiting high or undetectable glass-transition temperatures and high thermo-oxidative stabilities. Compounds used to make thermally stable, glassy polymers.

  19. 7 CFR 915.64 - Termination.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE AVOCADOS GROWN IN SOUTH FLORIDA Order... effectuate the declared policy of the act. (c) The Secretary shall terminate the provisions of this...

  20. 7 CFR 915.64 - Termination.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE AVOCADOS GROWN IN SOUTH FLORIDA Order... effectuate the declared policy of the act. (c) The Secretary shall terminate the provisions of this...

  1. 7 CFR 966.84 - Termination.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE TOMATOES GROWN IN FLORIDA Order... effectuate the declared policy of the act. (c) The Secretary shall terminate the provisions of this...

  2. 7 CFR 966.84 - Termination.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE TOMATOES GROWN IN FLORIDA Order... effectuate the declared policy of the act. (c) The Secretary shall terminate the provisions of this...

  3. 7 CFR 915.64 - Termination.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE AVOCADOS GROWN IN SOUTH FLORIDA Order... effectuate the declared policy of the act. (c) The Secretary shall terminate the provisions of this...

  4. 7 CFR 915.64 - Termination.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE AVOCADOS GROWN IN SOUTH FLORIDA Order... effectuate the declared policy of the act. (c) The Secretary shall terminate the provisions of this...

  5. 7 CFR 966.84 - Termination.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE TOMATOES GROWN IN FLORIDA Order... effectuate the declared policy of the act. (c) The Secretary shall terminate the provisions of this...

  6. 7 CFR 915.64 - Termination.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE AVOCADOS GROWN IN SOUTH FLORIDA Order... effectuate the declared policy of the act. (c) The Secretary shall terminate the provisions of this...

  7. 7 CFR 966.84 - Termination.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE TOMATOES GROWN IN FLORIDA Order... effectuate the declared policy of the act. (c) The Secretary shall terminate the provisions of this...

  8. Termination of Faculty due to Financial Exigency.

    ERIC Educational Resources Information Center

    Holloway, John P.

    1980-01-01

    Recent court cases involving termination of faculty due to financial exigency are summarized. Sections include an introduction, definition, a survey of recent cases, recommendations, conclusions and questions, and a bibliography. (Author/LC)

  9. 48 CFR 801.690-7 - Termination.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Responsibilities 801.690-7 Termination. (a) The DSPE (for all warrant levels) or HCA (for Micro-purchase Level and... changes in the status (e.g., departure, name, position, or grade change) of a micro-purchase cardholder...

  10. 48 CFR 801.690-7 - Termination.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Responsibilities 801.690-7 Termination. (a) The DSPE (for all warrant levels) or HCA (for Micro-purchase Level and... changes in the status (e.g., departure, name, position, or grade change) of a micro-purchase cardholder...

  11. Procedure for potting electrical cable assembly terminations

    NASA Technical Reports Server (NTRS)

    Williams, H. F.

    1972-01-01

    Procedures for the safe cleaning and potting of cable assembly terminations are given. Data cover primer application and injection of the potting compound. Required safety precautions for the process are listed.

  12. Teleglobe's international Mobile Earth Terminal service

    NASA Astrophysics Data System (ADS)

    Duchoeny, Joel

    In 1990, Teleglobe Canada initiated a developmental Mobile Earth Terminal (MET) service. By the use of the INMARSAT satellite, the service can provide voice and data communication capabilities between lightweight, self-contained terminals and the international public telephone network. Initially, the developmental program provides service to a test group of up to 18 terminals. Plans are under way to introduce a global digital service to the public by 1991-92. Such a service will have the potential to solve communication problems for such users as news media, diplomatic corps, disaster relief teams, construction teams in remote areas, and expeditions. The terminals are briefcase size and include L-band transmitter, receiver, and antenna, a power supply, and batteries. Equipment setup can be easily done in 1-2 minutes. Calls are made by aiming the antenna at the MARECS B2 satellite (covering the Atlantic Ocean region) and dialing the appropriate number.

  13. Four Terminal Gallium Nitride MOSFETs

    NASA Astrophysics Data System (ADS)

    Veety, Matthew Thomas

    All reported gallium nitride (GaN) transistors to date have been three-terminal devices with source, drain, and gate electrodes. In the case of GaN MOSFETs, this leaves the bulk of the device at a floating potential which can impact device threshold voltage. In more traditional silicon-based MOSFET fabrication a bulk contact can be made on the back side of the silicon wafer. For GaN grown on sapphire substrates, however, this is not possible and an alternate, front-side bulk contact must be investigated. GaN is a III-V, wide band gap semiconductor that as promising material parameters for use in high frequency and high power applications. Possible applications are in the 1 to 10 GHz frequency band and power inverters for next generation grid solid state transformers and inverters. GaN has seen significant academic and commercial research for use in Heterojunction Field Effect Transistors (HFETs). These devices however are depletion-mode, meaning the device is considered "on" at zero gate bias. A MOSFET structure allows for enhancement mode operation, which is normally off. This mode is preferrable in high power applications as the device has lower off-state power consumption and is easier to implement in circuits. Proper surface passivation of seminconductor surface interface states is an important processing step for any device. Preliminary research on surface treatments using GaN wet etches and depletion-mode GaN devices utilizing this process are discussed. Devices pretreated with potassium pursulfate prior to gate dielectric deposition show significant device improvements. This process can be applied to any current GaN FET. Enhancement-mode GaN MOSFETs were fabricated on magnesium doped p-type Wurtzite gallium nitride grown by Metal Organic Chemical Vapor Deposition (MOCVD) on c-plane sapphire substrates. Devices utilized ion implant source and drain which was activated under NH3 overpressure in MOCVD. Also, devices were fabricated with a SiO2 gate dielectric

  14. Ethynyl-Terminated Ester Oligomers and Polymers

    NASA Technical Reports Server (NTRS)

    Hergenrother, P. M.; Havens, S. J.

    1985-01-01

    Polyesters of various molecular weights terminated with ethynyl groups. As ethynyl-terminated polyesters are exposed to elevated temperatures, thermally induced reaction of ethynyl groups occurs to provide cross-linking and chain extension. Reaction raises use temperature of polymer and greatly improves resistance to solvents. New materials produced by this process potentially useful as adhesives, composite matrices, solvent-resistant coatings, membranes, and films.

  15. An efficient parallel termination detection algorithm

    SciTech Connect

    Baker, A. H.; Crivelli, S.; Jessup, E. R.

    2004-05-27

    Information local to any one processor is insufficient to monitor the overall progress of most distributed computations. Typically, a second distributed computation for detecting termination of the main computation is necessary. In order to be a useful computational tool, the termination detection routine must operate concurrently with the main computation, adding minimal overhead, and it must promptly and correctly detect termination when it occurs. In this paper, we present a new algorithm for detecting the termination of a parallel computation on distributed-memory MIMD computers that satisfies all of those criteria. A variety of termination detection algorithms have been devised. Of these, the algorithm presented by Sinha, Kale, and Ramkumar (henceforth, the SKR algorithm) is unique in its ability to adapt to the load conditions of the system on which it runs, thereby minimizing the impact of termination detection on performance. Because their algorithm also detects termination quickly, we consider it to be the most efficient practical algorithm presently available. The termination detection algorithm presented here was developed for use in the PMESC programming library for distributed-memory MIMD computers. Like the SKR algorithm, our algorithm adapts to system loads and imposes little overhead. Also like the SKR algorithm, ours is tree-based, and it does not depend on any assumptions about the physical interconnection topology of the processors or the specifics of the distributed computation. In addition, our algorithm is easier to implement and requires only half as many tree traverses as does the SKR algorithm. This paper is organized as follows. In section 2, we define our computational model. In section 3, we review the SKR algorithm. We introduce our new algorithm in section 4, and prove its correctness in section 5. We discuss its efficiency and present experimental results in section 6.

  16. Initial Climate Response to a Termination Shock

    NASA Astrophysics Data System (ADS)

    Irvine, Peter

    2015-04-01

    The risk of the termination of a deployment of solar radiation management (SRM) geoengineering has been raised as one of the key concerns about these ideas. Early studies demonstrated that a rapid warming of the climate would follow such a termination with global mean temperatures rapidly rising towards the levels that would have been expected in the absence of SRM geoengineering. Further work has noted the contrasting timescale of the adjustment of global mean temperature and sea-level rise, with sea-levels responding much slower and not reaching the same levels as would have been the case in the absence of SRM geoengineering. Whilst these previous studies have shown the basics of the response to a termination of SRM, a detailed analysis of the climate response in the first months or years of a termination has not been investigated. To conduct such an analysis tens of simulations with a termination of SRM are conducted, starting from the end of a G1 simulation with the HadCM3 model. The termination is initiated in Spring, Summer, Autumn and Winter to investigate whether the response depends on the season. Analyzing these results I find some novel dynamic responses in the initial months and years following a termination of SRM which have not been seen in previous studies which employed decadal-scale averages. These include: A reduction in the global-scale hydrological cycle's intensity in the first weeks following termination, counter to the longer-term increase; An almost instantaneous adjustment of land-mean precipitation to the equilibrium value; And substantial shifts in the pattern of precipitation in the initial years that are distinct from those seen in the equilibrium response and which are characterized by large increases in terrestrial precipitation and runoff in many regions.

  17. Terminal chaos for information processing in neurodynamics.

    PubMed

    Zak, M

    1991-01-01

    New nonlinear phenomenon-terminal chaos caused by failure of the Lipschitz condition at equilibrium points of dynamical systems is introduced. It is shown that terminal chaos has a well organized probabilistic structure which can be predicted and controlled. This gives an opportunity to exploit this phenomenon for information processing. It appears that chaotic states of neurons activity are associated with higher level of cognitive processes such as generalization and abstraction.

  18. 47 CFR 32.6362 - Other terminal equipment expense.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Other terminal equipment expense. 32.6362... Other terminal equipment expense. This account shall include expenses associated with other terminal equipment....

  19. 47 CFR 32.6351 - Public telephone terminal equipment expense.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Public telephone terminal equipment expense. 32....6351 Public telephone terminal equipment expense. This account shall include expenses associated with public telephone terminal equipment....

  20. Modular approach for satellite communication ground terminals

    NASA Technical Reports Server (NTRS)

    Gould, G. R.

    1984-01-01

    The trend in satellite communications is toward completely digital, time division multiple access (TDMA) systems with uplink and downlink data rates dictated by the type of service offered. Trunking terminals will operate in the 550 MBPS (megabit per second) region uplink and downlink, whereas customer premise service (CPS) terminals will operate in the 25 to 10 MBPS region uplink and in the 200 MBPS region downlink. Additional criteria for the ground terminals will be to maintain clock sychronization with the system and burst time integrity to within a matter of nanoseconds, to process required order-fire information, to provide adaptive data scrambing, and to compensate for variations in the user input output data rates, and for changes in range in the satellite communications links resulting from satellite perturbations in orbit. To achieve the required adaptability of a ground terminal to the above mentioned variables, programmable building blocks can be developed that will meet all of these requirements. To maintain system synchronization, i.e., all bursted data arriving at the satellite within assigned TDMA windows, ground terminal transmit data rates and burst timing must be maintained within tight tolerances. With a programmable synchronizer as the heart of the terminal timing generation, variable data rates and burst timing tolerances are achievable. In essence, the unit inputs microprocessor generated timing words and outputs discrete timing pulses.